From 383385700a13acc2bc4ad2ac7e78a445d9053d21 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Wed, 14 Aug 2019 22:42:24 -0700
Subject: [PATCH 01/26] A wasi_unstable description based on module types.

This sketches out a description of the current wasi_unstable API, using a syntax which anticipates the "module types" syntax [recently proposed to the CG](https://github.com/WebAssembly/meetings/blob/master/2019/CG-08-06.md#discuss-new-proposal-that-introduces-types-for-modules-and-instances-and-text-format-thereof-as-initially-discussed-in-design1289), though it does use a few extensions which can be easily lowered, and which mostly anticipate the [Interface Types](https://github.com/WebAssembly/webidl-bindings/issues/47#issuecomment-519717553) proposal.

This is derived from [the WatIDL proposal](https://github.com/WebAssembly/WASI/pull/64), though it differs in a few ways:
 - It doesn't yet do anything special for capabilities, for now. File descriptors are just integers, for now. But the idea is that we could add OCAP concepts later.

 - It uses a new `(flags ...)` construct in place of structs of Bool fields, to describe flags values. This allows us to explicitly declare the underlying wasm type for flags values.

 - Types used by the API are declared outside of the moduletype, because we're using wat syntax as much as possible, and there, `(type ...)` inside a module declares an entry in the type section, which isn't what's intended here.

The extensions to module types are:
 - It uses `string`, `array`, and `{s,u}{8,16,32,64}` types, which are expected to be provided in some form by the Interface Types proposal.  For now though, they can all be lowered in straightforward ways, by assuming that `string` is always just UTF-8.

 - It adds `typename` declarations, which can name any wasm type, and of the extra types mentioned in the previous item, or `struct`, `enum`, or `flags`.

 - It declares functions with multiple return values, which for now will need to be lowered to output (pointer) parameters.
---
 design/wasi_unstable/wasi_unstable.wati | 1206 +++++++++++++++++++++++
 1 file changed, 1206 insertions(+)
 create mode 100644 design/wasi_unstable/wasi_unstable.wati

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/wasi_unstable.wati
new file mode 100644
index 00000000..1dd06791
--- /dev/null
+++ b/design/wasi_unstable/wasi_unstable.wati
@@ -0,0 +1,1206 @@
+;; The wasi_unstable module type.
+;;
+;; Some content here is derived from [CloudABI](https://github.com/NuxiNL/cloudabi).
+
+(typename $size_t u32)
+(typename $string_array (array string))
+
+;; Non-negative file size or length of a region within a file.
+(typename $filesize_t u64)
+
+;; Timestamp in nanoseconds.
+(typename $timestamp_t u64)
+
+;; Identifiers for clocks.
+(typename $clockid_t
+  (enum u32
+    ;; The store-wide monotonic clock, which is defined as a clock measuring
+    ;; real time, whose value cannot be adjusted and which cannot have negative
+    ;; clock jumps. The epoch of this clock is undefined. The absolute time
+    ;; value of this clock therefore has no meaning.
+    $CLOCK_MONOTONIC
+    ;; The CPU-time clock associated with the current process.
+    $CLOCK_PROCESS_CPUTIME_ID
+    ;; The clock measuring real time. Time value zero corresponds with
+    ;; 1970-01-01T00:00:00Z.
+    $CLOCK_REALTIME
+    ;; The CPU-time clock associated with the current thread.
+    $CLOCK_THREAD_CPUTIME_ID
+  )
+)
+
+;; Error codes returned by functions.
+;; Not all of these error codes are returned by the functions provided by this
+;; API; some are used in higher-level library layers, and others are provided
+;; merely for alignment with POSIX.
+(typename $errno_t
+  (enum u16
+    ;; No error occurred. System call completed successfully.
+    $ESUCCESS
+    ;; Argument list too long.
+    $E2BIG
+    ;; Permission denied.
+    $EACCES
+    ;; Address in use.
+    $EADDRINUSE
+    ;; Address not available.
+    $EADDRNOTAVAIL
+    ;; Address family not supported.
+    $EAFNOSUPPORT
+    ;; Resource unavailable, or operation would block.
+    $EAGAIN
+    ;; Connection already in progress.
+    $EALREADY
+    ;; Bad file descriptor.
+    $EBADF
+    ;; Bad message.
+    $EBADMSG
+    ;; Device or resource busy.
+    $EBUSY
+    ;; Operation canceled.
+    $ECANCELED
+    ;; No child processes.
+    $ECHILD
+    ;; Connection aborted.
+    $ECONNABORTED
+    ;; Connection refused.
+    $ECONNREFUSED
+    ;; Connection reset.
+    $ECONNRESET
+    ;; Resource deadlock would occur.
+    $EDEADLK
+    ;; Destination address required.
+    $EDESTADDRREQ
+    ;; Mathematics argument out of domain of function.
+    $EDOM
+    ;; Reserved.
+    $EDQUOT
+    ;; File exists.
+    $EEXIST
+    ;; Bad address.
+    $EFAULT
+    ;; File too large.
+    $EFBIG
+    ;; Host is unreachable.
+    $EHOSTUNREACH
+    ;; Identifier removed.
+    $EIDRM
+    ;; Illegal byte sequence.
+    $EILSEQ
+    ;; Operation in progress.
+    $EINPROGRESS
+    ;; Interrupted function.
+    $EINTR
+    ;; Invalid argument.
+    $EINVAL
+    ;; I/O error.
+    $EIO
+    ;; Socket is connected.
+    $EISCONN
+    ;; Is a directory.
+    $EISDIR
+    ;; Too many levels of symbolic links.
+    $ELOOP
+    ;; File descriptor value too large.
+    $EMFILE
+    ;; Too many links.
+    $EMLINK
+    ;; Message too large.
+    $EMSGSIZE
+    ;; Reserved.
+    $EMULTIHOP
+    ;; Filename too long.
+    $ENAMETOOLONG
+    ;; Network is down.
+    $ENETDOWN
+    ;; Connection aborted by network.
+    $ENETRESET
+    ;; Network unreachable.
+    $ENETUNREACH
+    ;; Too many files open in system.
+    $ENFILE
+    ;; No buffer space available.
+    $ENOBUFS
+    ;; No such device.
+    $ENODEV
+    ;; No such file or directory.
+    $ENOENT
+    ;; Executable file format error.
+    $ENOEXEC
+    ;; No locks available.
+    $ENOLCK
+    ;; Reserved.
+    $ENOLINK
+    ;; Not enough space.
+    $ENOMEM
+    ;; No message of the desired type.
+    $ENOMSG
+    ;; Protocol not available.
+    $ENOPROTOOPT
+    ;; No space left on device.
+    $ENOSPC
+    ;; Function not supported.
+    $ENOSYS
+    ;; The socket is not connected.
+    $ENOTCONN
+    ;; Not a directory or a symbolic link to a directory.
+    $ENOTDIR
+    ;; Directory not empty.
+    $ENOTEMPTY
+    ;; State not recoverable.
+    $ENOTRECOVERABLE
+    ;; Not a socket.
+    $ENOTSOCK
+    ;; Not supported, or operation not supported on socket.
+    $ENOTSUP
+    ;; Inappropriate I/O control operation.
+    $ENOTTY
+    ;; No such device or address.
+    $ENXIO
+    ;; Value too large to be stored in data type.
+    $EOVERFLOW
+    ;; Previous owner died.
+    $EOWNERDEAD
+    ;; Operation not permitted.
+    $EPERM
+    ;; Broken pipe.
+    $EPIPE
+    ;; Protocol error.
+    $EPROTO
+    ;; Protocol not supported.
+    $EPROTONOSUPPORT
+    ;; Protocol wrong type for socket.
+    $EPROTOTYPE
+    ;; Result too large.
+    $ERANGE
+    ;; Read-only file system.
+    $EROFS
+    ;; Invalid seek.
+    $ESPIPE
+    ;; No such process.
+    $ESRCH
+    ;; Reserved.
+    $ESTALE
+    ;; Connection timed out.
+    $ETIMEDOUT
+    ;; Text file busy.
+    $ETXTBSY
+    ;; Cross-device link.
+    $EXDEV
+    ;; Extension: Capabilities insufficient.
+    $ENOTCAPABLE
+  )
+)
+
+;; File descriptor rights, determining which actions may be performed.
+(typename $rights_t
+  (flags u64
+    ;; The right to invoke __wasi_fd_datasync().
+    ;;
+    ;; If __WASI_RIGHT_PATH_OPEN is set, includes the right to invoke
+    ;` __wasi_path_open() with __WASI_FDFLAG_DSYNC.
+    (flag $RIGHT_FD_DATASYNC)
+    ;; The right to invoke __wasi_fd_read() and __wasi_sock_recv().
+    ;;
+    ;; If __WASI_RIGHT_FD_SEEK is set, includes the right to invoke
+    ;; __wasi_fd_pread().
+    (flag $RIGHT_FD_READ)
+    ;; The right to invoke __wasi_fd_seek(). This flag implies __WASI_RIGHT_FD_TELL.
+    (flag $RIGHT_FD_SEEK)
+    ;; The right to invoke __wasi_fd_fdstat_set_flags().
+    (flag $RIGHT_FD_FDSTAT_SET_FLAGS)
+    ;; The right to invoke __wasi_fd_sync().
+    ;;
+    ;; If __WASI_RIGHT_PATH_OPEN is set, includes the right to invoke
+    ;; __wasi_path_open() with __WASI_FDFLAG_RSYNC and __WASI_FDFLAG_DSYNC.
+    (flag $RIGHT_FD_SYNC)
+    ;; The right to invoke __wasi_fd_seek() in such a way that the file offset
+    ;; remains unaltered (i.e., __WASI_WHENCE_CUR with offset zero), or to
+    ;; invoke __wasi_fd_tell().
+    (flag $RIGHT_FD_TELL)
+    ;; The right to invoke __wasi_fd_write() and __wasi_sock_send().
+    ;; If __WASI_RIGHT_FD_SEEK is set, includes the right to invoke __wasi_fd_pwrite().
+    (flag $RIGHT_FD_WRITE)
+    ;; The right to invoke __wasi_fd_advise().
+    (flag $RIGHT_FD_ADVISE)
+    ;; The right to invoke __wasi_fd_allocate().
+    (flag $RIGHT_FD_ALLOCATE)
+    ;; The right to invoke __wasi_path_create_directory().
+    (flag $RIGHT_PATH_CREATE_DIRECTORY)
+    ;; If __WASI_RIGHT_PATH_OPEN is set, the right to invoke __wasi_path_open() with __WASI_O_CREAT.
+    (flag $RIGHT_PATH_CREATE_FILE)
+    ;; The right to invoke __wasi_path_link() with the file descriptor as the source directory.
+    (flag $RIGHT_PATH_LINK_SOURCE)
+    ;; The right to invoke __wasi_path_link() with the file descriptor as the target directory.
+    (flag $RIGHT_PATH_LINK_TARGET)
+    ;; The right to invoke __wasi_path_open().
+    (flag $RIGHT_PATH_OPEN)
+    ;; The right to invoke __wasi_fd_readdir().
+    (flag $RIGHT_FD_READDIR)
+    ;; The right to invoke __wasi_path_readlink().
+    (flag $RIGHT_PATH_READLINK)
+    ;; The right to invoke __wasi_path_rename() with the file descriptor as the source directory.
+    (flag $RIGHT_PATH_RENAME_SOURCE)
+    ;; The right to invoke __wasi_path_rename() with the file descriptor as the target directory.
+    (flag $RIGHT_PATH_RENAME_TARGET)
+    ;; The right to invoke __wasi_path_filestat_get().
+    (flag $RIGHT_PATH_FILESTAT_GET)
+    ;; The right to change a file's size (there is no __wasi_path_filestat_set_size()).
+    ;; If __WASI_RIGHT_PATH_OPEN is set, includes the right to invoke __wasi_path_open() with __WASI_O_TRUNC.
+    (flag $RIGHT_PATH_FILESTAT_SET_SIZE)
+    ;; The right to invoke __wasi_path_filestat_set_times().
+    (flag $RIGHT_PATH_FILESTAT_SET_TIMES)
+    ;; The right to invoke __wasi_fd_filestat_get().
+    (flag $RIGHT_FD_FILESTAT_GET)
+    ;; The right to invoke __wasi_fd_filestat_set_size().
+    (flag $RIGHT_FD_FILESTAT_SET_SIZE)
+    ;; The right to invoke __wasi_fd_filestat_set_times().
+    (flag $RIGHT_FD_FILESTAT_SET_TIMES)
+    ;; The right to invoke __wasi_path_symlink().
+    (flag $RIGHT_PATH_SYMLINK)
+    ;; The right to invoke __wasi_path_unlink_file().
+    (flag $RIGHT_PATH_UNLINK_FILE)
+    ;; The right to invoke __wasi_path_remove_directory().
+    (flag $RIGHT_PATH_REMOVE_DIRECTORY)
+    ;; If __WASI_RIGHT_FD_READ is set, includes the right to invoke __wasi_poll_oneoff() to subscribe to __WASI_EVENTTYPE_FD_READ.
+    ;; If __WASI_RIGHT_FD_WRITE is set, includes the right to invoke __wasi_poll_oneoff() to subscribe to __WASI_EVENTTYPE_FD_WRITE.
+    (flag $RIGHT_POLL_FD_READWRITE)
+    ;; The right to invoke __wasi_sock_shutdown().
+    (flag $RIGHT_SOCK_SHUTDOWN)
+  )
+)
+
+;; a file descriptor index
+(typename $fd_t u32)
+
+(typename $iovec_t_array (array $iovec_t))
+(typename $ciovec_t_array (array $ciovec_t))
+
+;; A region of memory for scatter/gather reads.
+(typename $iovec_t
+  (struct
+    ;; The address and length of the buffer to be filled.
+    (field $buf data)
+    (field $buf_len data)
+  )
+)
+
+;; A region of memory for scatter/gather writes.
+(typename $ciovec_t
+  (struct
+    ;; The address and length of the buffer to be written.
+    (field $buf data)
+    (field $buf_len data)
+  )
+)
+
+;; Relative offset within a file.
+(typename $filedelta_t s64)
+
+;; The position relative to which to set the offset of the file descriptor.
+(typename $whence_t
+  (enum u8
+    ;; Seek relative to current position.
+    $WHENCE_CUR
+    ;; Seek relative to end-of-file.
+    $WHENCE_END
+    ;; Seek relative to start-of-file.
+    $WHENCE_SET
+  )
+)
+
+;; A reference to the offset of a directory entry.
+(typename $dircookie_t u64)
+
+;; The type for the $d_namelen field of $dirent_t.
+(typename $dirnamlen_t u32)
+
+;; A directory entry.
+(typename $dirent_t
+  (struct
+    ;; The offset of the next directory entry stored in this directory.
+    (field $d_next $dircookie_t)
+    ;; The serial number of the file referred to by this directory entry.
+    (field $d_ino $inode_t)
+    ;; The length of the name of the directory entry.
+    (field $d_namlen $dirnamelen_t)
+    ;; The type of the file referred to by this directory entry.
+    (field $d_type $filetype_t)
+  )
+)
+
+;; File or memory access pattern advisory information.
+(typename $advice_t
+  (enum u8
+    ;; The application expects that it will not access the specified data in the near future.
+    $ADVICE_DONTNEED
+    ;; The application expects to access the specified data once and then not reuse it thereafter.
+    $ADVICE_NOREUSE
+    ;; The application has no advice to give on its behavior with respect to the specified data.
+    $ADVICE_NORMAL
+    ;; The application expects to access the specified data in a random order.
+    $ADVICE_RANDOM
+    ;; The application expects to access the specified data sequentially from lower offsets to higher offsets.
+    $ADVICE_SEQUENTIAL
+    ;; The application expects to access the specified data in the near future.
+    $ADVICE_WILLNEED
+  )
+)
+
+;; File descriptor flags.
+(typename $fdflags_t
+  (flags u16
+    ;; Append mode: Data written to the file is always appended to the file's end.
+    (flag $FDFLAG_APPEND)
+    ;; Write according to synchronized I/O data integrity completion. Only the data stored in the file is synchronized.
+    (flag $FDFLAG_DSYNC)
+    ;; Non-blocking mode.
+    (flag $FDFLAG_NONBLOCK)
+    ;; Synchronized read I/O operations.
+    (flag $FDFLAG_RSYNC)
+    ;; Write according to synchronized I/O file integrity completion. In
+    ;; addition to synchronizing the data stored in the file, the implementation
+    ;; may also synchronously update the file's metadata.
+    (flag $FDFLAG_SYNC)
+  )
+)
+
+;; File descriptor attributes.
+(typename $fdstat_t
+  (struct
+    ;; File type.
+    (field $fs_filetype $filetype_t)
+    ;; File descriptor flags.
+    (field $fs_flags $fdflags_t)
+    ;; Rights that apply to this file descriptor.
+    (field $fs_rights_base $rights_t)
+    ;; Maximum set of rights that may be installed on new file descriptors that
+    ;; are created through this file descriptor, e.g., through
+    ;; __wasi_path_open().
+    (field $fs_rights_inheriting $rights_t)
+  )
+)
+
+;; Identifier for a device containing a file system. Can be used in combination
+;; with __wasi_inode_t to uniquely identify a file or directory in the
+;; filesystem.
+(typename $device_t u64)
+
+;; The type of a file descriptor or file.
+(typename $filetype_t
+  (enum u8
+    ;; The type of the file descriptor or file is unknown or is different from any of the other types specified.
+    $FILETYPE_UNKNOWN
+    ;; The file descriptor or file refers to a block device inode.
+    $FILETYPE_BLOCK_DEVICE
+    ;; The file descriptor or file refers to a character device inode.
+    $FILETYPE_CHARACTER_DEVICE
+    ;; The file descriptor or file refers to a directory inode.
+    $FILETYPE_DIRECTORY
+    ;; The file descriptor or file refers to a regular file inode.
+    $FILETYPE_REGULAR_FILE
+    ;; The file descriptor or file refers to a datagram socket.
+    $FILETYPE_SOCKET_DGRAM
+    ;; The file descriptor or file refers to a byte-stream socket.
+    $FILETYPE_SOCKET_STREAM
+    ;; The file refers to a symbolic link inode.
+    $FILETYPE_SYMBOLIC_LINK
+  )
+)
+
+;; Which file time attributes to adjust.
+(typename $fstflags_t
+  (flags u16
+    ;; Adjust the last data access timestamp to the value stored in __wasi_filestat_t::st_atim.
+    (flag $FILESTAT_SET_ATIM)
+    ;; Adjust the last data access timestamp to the time of clock __WASI_CLOCK_REALTIME.
+    (flag $FILESTAT_SET_ATIM_NOW)
+    ;; Adjust the last data modification timestamp to the value stored in __wasi_filestat_t::st_mtim.
+    (flag $FILESTAT_SET_MTIM)
+    ;; Adjust the last data modification timestamp to the time of clock __WASI_CLOCK_REALTIME.
+    (flag $FILESTAT_SET_MTIM_NOW)
+  )
+)
+
+;; File serial number that is unique within its file system.
+(typename $inode_t u64)
+
+;; Flags determining the method of how paths are resolved.
+(typename $lookupflags_t
+  (flags u32
+    ;; As long as the resolved path corresponds to a symbolic link, it is expanded.
+    (flag $LOOKUP_SYMLINK_FOLLOW)
+  )
+)
+
+;; Open flags used by __wasi_path_open().
+(typename $oflags_t
+  (flags u16
+    ;; Create file if it does not exist.
+    (flag $O_CREAT)
+    ;; Fail if not a directory.
+    (flag $O_DIRECTORY)
+    ;; Fail if file already exists.
+    (flag $O_EXCL)
+    ;; Truncate file to size 0.
+    (flag $O_TRUNC)
+  )
+)
+
+;; Number of hard links to an inode.
+(typename $linkcount_t u32)
+
+;; File attributes.
+(typename $filestat_t
+  (struct
+    ;; Device ID of device containing the file.
+    (field $st_dev $device_t)
+    ;; File serial number.
+    (field $st_ino $inode_t)
+    ;; File type.
+    (field $st_filetype $filetype_t)
+    ;; Number of hard links to the file.
+    (field $st_nlink $linkcount_t)
+    ;; For regular files, the file size in bytes. For symbolic links, the length in bytes of the pathname contained in the symbolic link.
+    (field $st_size $filesize_t)
+    ;; Last data access timestamp.
+    (field $st_atim $timestamp_t)
+    ;; Last data modification timestamp.
+    (field $st_mtim $timestamp_t)
+    ;; Last file status change timestamp.
+    (field $st_ctim $timestamp_t)
+  )
+)
+
+;; User-provided value that may be attached to objects that is retained when extracted from the implementation.
+(typename $userdata_t u64)
+
+;; An event that occurred.
+(typename $event_t
+  (struct
+    ;; User-provided value that got attached to __wasi_subscription_t::userdata.
+    (field $userdata $userdata_t)
+    ;; If non-zero, an error that occurred while processing the subscription request.
+    (field $error $errno_t)
+    ;; The type of the event that occurred.
+    (field $type $eventtype_t)
+    (field $u
+      (typename union
+        ;; When type is __WASI_EVENTTYPE_FD_READ or __WASI_EVENTTYPE_FD_WRITE:
+        (field $fd_readwrite
+          (typename stuct
+            ;; The number of bytes available for reading or writing.
+            (field $nbytes $filesize_t)
+            ;; The state of the file descriptor.
+            (field $flags $eventrwflags_t)
+          )
+        )
+        (field $else Null)
+      )
+    )
+  )
+)
+
+;; The state of the file descriptor subscribed to with __WASI_EVENTTYPE_FD_READ or __WASI_EVENTTYPE_FD_WRITE.
+(typename $eventrwflags_t
+  (flags u16
+    ;; The peer of this socket has closed or disconnected.
+    (flag $EVENT_FD_READWRITE_HANGUP)
+  )
+)
+
+;; Type of a subscription to an event or its occurrence.
+(typename $eventtype_t
+  (flags u8
+    ;; The time value of clock __wasi_subscription_t::u.clock.clock_id has reached timestamp __wasi_subscription_t::u.clock.timeout.
+    (flag $EVENTTYPE_CLOCK)
+    ;; File descriptor __wasi_subscription_t::u.fd_readwrite.fd has data available for reading. This event always triggers for regular files.
+    (flag $EVENTTYPE_FD_READ)
+    ;; File descriptor __wasi_subscription_t::u.fd_readwrite.fd has capacity available for writing. This event always triggers for regular files.
+    (flag $EVENTTYPE_FD_WRITE)
+  )
+)
+
+;; Flags determining how to interpret the timestamp provided in __wasi_subscription_t::u.clock.timeout.
+(typename $subclockflags_t
+  (flags u16
+    ;; If set, treat the timestamp provided in
+    ;; __wasi_subscription_t::u.clock.timeout as an absolute timestamp of clock
+    ;; __wasi_subscription_t::u.clock.clock_id. If clear, treat the timestamp
+    ;; provided in __wasi_subscription_t::u.clock.timeout relative to the
+    ;; current time value of clock __wasi_subscription_t::u.clock.clock_id.
+    (flag $SUBSCRIPTION_CLOCK_ABSTIME)
+  )
+)
+
+;; Subscription to an event.
+(typename $subscription_t
+  (struct
+    ;; User-provided value that is attached to the subscription in the implementation and returned through __wasi_event_t::userdata.
+    (field $userdata $userdata_t)
+    ;; The type of the event to which to subscribe.
+    (field $type $eventtype_t)
+    (field
+      (type
+        (union
+          ;; When type is __WASI_EVENTTYPE_CLOCK
+          (field $clock
+            (typename
+              (struct
+                ;; The user-defined unique identifier of the clock.
+                (field $identifier $userdata_t)
+                ;; The clock against which to compare the timestamp.
+                (field $clock_id $clockid_t)
+                ;; The absolute or relative timestamp.
+                (field $timeout $timestamp_t)
+                ;; The amount of time that the implementation may wait additionally to coalesce with other events.
+                ;; Flags specifying whether the timeout is absolute or relative
+                (field $precision $timestamp_t)
+              )
+            )
+          )
+          ;; When type is __WASI_EVENTTYPE_FD_READ or __WASI_EVENTTYPE_FD_WRITE:
+          (field $fd_readwrite
+            (type
+              (struct
+                ;; The file descriptor on which to wait for it to become ready for reading or writing.
+                (field $file_descriptor $fd_t)
+              )
+            )
+          )
+        )
+      )
+    )
+  )
+)
+
+;; Exit code generated by a process when exiting.
+(typename $exitcode_t u32)
+
+;; Signal condition.
+(typename $signal_t
+  (enum u8
+    ;; Process abort signal.
+    ;; Action: Terminates the process.
+    $SIGABRT
+    ;; Alarm clock.
+    ;; Action: Terminates the process.
+    $SIGALRM
+    ;; Access to an undefined portion of a memory object.
+    ;; Action: Terminates the process.
+    $SIGBUS
+    ;; Child process terminated, stopped, or continued.
+    ;; Action: Ignored.
+    $SIGCHLD
+    ;; Continue executing, if stopped.
+    ;; Action: Continues executing, if stopped.
+    $SIGCONT
+    ;; Erroneous arithmetic operation.
+    ;; Action: Terminates the process.
+    $SIGFPE
+    ;; Hangup.
+    ;; Action: Terminates the process.
+    $SIGHUP
+    ;; Illegal instruction.
+    ;; Action: Terminates the process.
+    $SIGILL
+    ;; Terminate interrupt signal.
+    ;; Action: Terminates the process.
+    $SIGINT
+    ;; Kill.
+    ;; Action: Terminates the process.
+    $SIGKILL
+    ;; Write on a pipe with no one to read it.
+    ;; Action: Ignored.
+    $SIGPIPE
+    ;; Terminal quit signal.
+    ;; Action: Terminates the process.
+    $SIGQUIT
+    ;; Invalid memory reference.
+    ;; Action: Terminates the process.
+    $SIGSEGV
+    ;; Stop executing.
+    ;; Action: Stops executing.
+    $SIGSTOP
+    ;; Bad system call.
+    ;; Action: Terminates the process.
+    $SIGSYS
+    ;; Termination signal.
+    ;; Action: Terminates the process.
+    $SIGTERM
+    ;; Trace/breakpoint trap.
+    ;; Action: Terminates the process.
+    $SIGTRAP
+    ;; Terminal stop signal.
+    ;; Action: Stops executing.
+    $SIGTSTP
+    ;; Background process attempting read.
+    ;; Action: Stops executing.
+    $SIGTTIN
+    ;; Background process attempting write.
+    ;; Action: Stops executing.
+    $SIGTTOU
+    ;; High bandwidth data is available at a socket.
+    ;; Action: Ignored.
+    $SIGURG
+    ;; User-defined signal 1.
+    ;; Action: Terminates the process.
+    $SIGUSR1
+    ;; User-defined signal 2.
+    ;; Action: Terminates the process.
+    $SIGUSR2
+    ;; Virtual timer expired.
+    ;; Action: Terminates the process.
+    $SIGVTALRM
+    ;; CPU time limit exceeded.
+    ;; Action: Terminates the process.
+    $SIGXCPU
+    ;; File size limit exceeded.
+    ;; Action: Terminates the process.
+    $SIGXFSZ
+  )
+)
+
+;; Flags provided to __wasi_sock_recv().
+(typename $riflags_t
+  (flags u16
+    ;; Returns the message without removing it from the socket's receive queue.
+    (flag $SOCK_RECV_PEEK)
+    ;; On byte-stream sockets, block until the full amount of data can be returned.
+    (flag $SOCK_RECV_WAITALL)
+  )
+)
+
+;; Flags returned by __wasi_sock_recv().
+(typename $roflags_t
+  (flags u16
+    ;; Returned by __wasi_sock_recv(): Message data has been truncated.
+    (flag $SOCK_RECV_DATA_TRUNCATED)
+  )
+)
+
+;; Flags provided to __wasi_sock_send(). As there are currently no flags defined, it must be set to zero.
+(typename $siflags_t u16)
+
+;; Which channels on a socket to shut down.
+(typename $sdflags_t
+  (flags u8
+    ;; Disables further receive operations.
+    (flag $SHUT_RD)
+    ;; Disables further send operations.
+    (flag $SHUT_WR)
+  )
+)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;
+;; The wasi_unstable moduletype.
+;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(moduletype $wasi_unstable
+  ;; Linear memory used by the program.
+  (import "memory" (memory))
+
+  ;; The program entry point.
+  (import "_start" (func))
+
+  ;; Read command-line argument data.
+  ;; The size of the array should match that returned by `wasi_args_sizes_get()`
+  (func (export "args_get")
+    (result $error $errno_t)
+    (result $argv $string_array)
+  )
+  ;; Return command-line argument data sizes.
+  (func (export "args_sizes_get")
+    (result $error $errno_t)
+    ;; The number of arguments.
+    (result $argc $size_t)
+    ;; The size of the argument string data.
+    (result $argv_buf_size $size_t)
+  )
+
+  ;; Read environment variable data.
+  ;; The sizes of the buffers should match that returned by `environ.sizes_get()`.
+  (func (export "environ_get")
+    (result $error $errno_t)
+    (result $argv $string_array)
+  )
+  ;; Return command-line argument data sizes.
+  (func (export "environ_sizes_get")
+    ;; The number of arguments.
+    (result $argc $size_t)
+    ;; The size of the argument string data.
+    (result $argv_buf_size $size_t)
+  )
+
+  ;; Return the resolution of a clock.
+  ;; Implementations are required to provide a non-zero value for supported clocks. For unsupported clocks, return `WASI_EINVAL`
+  ;; Note: This is similar to `clock_getres` in POSIX.
+  (func (export "clock_res_get")
+    (result $error $errno_t)
+    ;; The clock for which to return the resolution.
+    (param $clock_id $clockid_t)
+    ;; The resolution of the clock.
+    (result $resolution $timestamp_t)
+  )
+  ;; Return the time value of a clock.
+  ;; Note: This is similar to `clock_gettime` in POSIX.
+  (func (export "clock_time_get")
+    ;; The clock for which to return the time.
+    (param $clock_id $clockid_t)
+    ;; The maximum lag (exclusive) that the returned time value may have, compared to its actual value.
+    (param $precision $timestamp_t)
+    (result $error $errno_t)
+    ;; The time value of the clock.
+    (result $time $timestamp_t)
+  )
+
+  ;; Provide file advisory information on a file descriptor.
+  ;; Note: This is similar to `posix_fadvise` in POSIX.
+  (func (export "fd_advise")
+    (param $self $fd_t)
+    (param $offset $filesize_t) ;; The offset within the file to which the advisory applies.
+    (param $len $filesize_t) ;; The length of the region to which the advisory applies.
+    (param $advice $advice_t) ;; The advice.
+    (result $error $errno_t)
+  )
+
+  ;; Force the allocation of space in a file.
+  ;; Note: This is similar to `posix_fallocate` in POSIX.
+  (func (export "fd_allocate")
+    (param $self $fd_t)
+    ;; The offset at which to start the allocation.
+    (param $offset $filesize_t)
+    ;; The length of the area that is allocated.
+    (param $len $filesize_t)
+    (result $error $errno_t)
+  )
+
+  ;; Close a file descriptor.
+  ;; Note: This is similar to `close` in POSIX.
+  (func (export "fd_close")
+    (param $self $fd_t)
+    (result $error $errno_t)
+  )
+
+  ;; Synchronize the data of a file to disk.
+  ;; Note: This is similar to `fdatasync` in POSIX.
+  (func (export "fd_datasync")
+    (param $self $fd_t)
+    (result $error $errno_t)
+  )
+
+  ;; Get the attributes of a file descriptor.
+  ;; Note: This returns similar flags to `fsync(fd, F_GETFL)` in POSIX, as well as additional fields.
+  (func (export "fd_fdstat_get")
+    (param $self $fd_t)
+    (result $error $errno_t)
+    ;; The buffer where the file descriptor's attributes are stored.
+    (result $fdstat_t)
+  )
+
+  ;; Adjust the flags associated with a file descriptor.
+  ;; Note: This is similar to `fcntl(fd, F_SETFL, flags)` in POSIX.
+  (func (export "fd_fdstat_set_flags")
+    (param $self $fd_t)
+    ;; The desired values of the file descriptor flags.
+    (param $flags $fdflags)
+    (result $error $errno_t)
+  )
+
+  ;;  Adjust the rights associated with a file descriptor.
+  ;; This can only be used to remove rights, and returns `ENOTCAPABLE` if called in a way that would attempt to add rights
+  (func (export "fd_fdstat_set_rights")
+    (param $self $fd_t)
+    ;; The desired rights of the file descriptor.
+    (param $fs_rights_base $rights_t)
+    (param $fs_rights_inheriting $rights_t)
+    (result $error $errno_t)
+  )
+
+  ;; Return the attributes of an open file.
+  (func (export "fd_filestat_get")
+    (param $self $fd_t)
+    (result $error $errno_t)
+    ;; The buffer where the file's attributes are stored.
+    (result $fs_rights_base $rights_t)
+  )
+
+  ;; Adjust the size of an open file. If this increases the file's size, the extra bytes are filled with zeros.
+  ;; Note: This is similar to `ftruncate` in POSIX.
+  (func (export "fd_filestat_set_size")
+    (param $self $fd_t)
+    ;; The desired file size.
+    (param $st_size $filesize_t)
+    (result $error $errno_t)
+  )
+
+  ;; Adjust the timestamps of an open file or directory.
+  ;; Note: This is similar to `futimens` in POSIX.
+  (func (export "fd_filestat_set_times")
+    (param $self $fd_t)
+    ;; The desired values of the data access timestamp.
+    (param $st_atim $timestamp_t)
+    ;; The desired values of the data modification timestamp.
+    (param $st_mtim $timestamp_t)
+    ;; A bitmask indicating which timestamps to adjust.
+    (param $fst_flags $fstflags_t)
+    (result $error $errno_t)
+  )
+
+  ;; Read from a file descriptor, without using and updating the file descriptor's offset.
+  ;; Note: This is similar to `preadv` in POSIX.
+  (func (export "fd_pread")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors in which to store data.
+    (param $iovs $iovec_t_array)
+    ;; The offset within the file at which to read.
+    (param $offset $filesize_t)
+    (result $error $errno_t)
+    ;; The number of bytes read.
+    (result $nread $size_t)
+  )
+
+  ;; Return a description of the given preopened file descriptor.
+  (func (export "fd_prestat_get")
+    (param $self $fd_t)
+    (result $error $errno_t)
+    ;; The buffer where the description is stored.
+    (result $buf $prestat_t)
+  )
+
+  ;; Return a description of the given preopened file descriptor.
+  (func (export "fd_prestat_dir_name")
+    (param $self $fd_t)
+    ;; A buffer into which to write the preopened directory name.
+    (param $path string)
+    (result $error $errno_t)
+  )
+
+  ;; Write to a file descriptor, without using and updating the file descriptor's offset.
+  ;; Note: This is similar to `pwritev` in POSIX.
+  (func (export "fd_pwrite")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors from which to retrieve data.
+    (param $iovs $iovec_t_array)
+    ;; The offset within the file at which to write.
+    (param $offset $filesize_t)
+    (result $error $errno_t)
+    ;; The number of bytes written.
+    (result $nwritten $size_t)
+  )
+
+  ;; Read from a file descriptor.
+  ;; Note: This is similar to `readv` in POSIX.
+  (func (export "fd_read")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors to which to store data.
+    (param $iovs $iovec_t_array)
+    (result $error $errno_t)
+    ;; The number of bytes read.
+    (result $nread $size_t)
+  )
+
+  ;; Read directory entries from a directory.
+  ;; When successful, the contents of the output buffer consist of a sequence of
+  ;; directory entries. Each directory entry consists of a dirent_t object,
+  ;; followed by dirent_t::d_namlen bytes holding the name of the directory
+  ;; entry.
+  ;;
+  ;; This function fills the output buffer as much as possible, potentially
+  ;; truncating the last directory entry. This allows the caller to grow its
+  ;; read buffer size in case it's too small to fit a single large directory
+  ;; entry, or skip the oversized directory entry.
+  (func (export "fd_readdir")
+    (param $self $fd_t)
+    ;; The buffer where directory entries are stored
+    (param $buf data)
+    ;; The location within the directory to start reading
+    (param $cookie $dircookie_t)
+    (result $error $errno_t)
+    ;; The number of bytes stored in the read buffer. If less than the size of the read buffer, the end of the directory has been reached.
+    (result $bufused $size_t)
+  )
+
+  ;; Atomically replace a file descriptor by renumbering another file descriptor.
+  ;; Due to the strong focus on thread safety, this environment does not provide a mechanism to duplicate or renumber a file descriptor to an arbitrary number, like dup2(). This would be prone to race conditions, as an actual file descriptor with the same number could be allocated by a different thread at the same time.
+  ;; This function provides a way to atomically renumber file descriptors, which would disappear if dup2() were to be removed entirely.
+  (func (export "fd_renumber")
+    (param $self $fd_t)
+    ;; The file descriptor to overwrite.
+    (param $to $fd_t)
+    (result $error $errno_t)
+  )
+
+  ;; Move the offset of a file descriptor.
+  ;; Note: This is similar to `lseek` in POSIX.
+  (func (export "fd_seek")
+    (param $self $fd_t)
+    ;; The number of bytes to move.
+    (param $offset $filedelta_t)
+    ;; The base from which the offset is relative.
+    (param $whence $whence_t)
+    (result $error $errno_t)
+    ;; The new offset of the file descriptor, relative to the start of the file.
+    (result $newoffset $filesize_t)
+  )
+
+  ;; Synchronize the data and metadata of a file to disk.
+  ;; Note: This is similar to `fsync` in POSIX.
+  (func (export "fd_sync")
+    (param $self $fd_t)
+    (result $error $errno_t)
+  )
+
+  ;; Return the current offset of a file descriptor.
+  ;; Note: This is similar to `lseek(fd, 0, SEEK_CUR)` in POSIX.
+  (func (export "fd_tell")
+    (param $self $fd_t)
+    (result $error $errno_t)
+    ;; The current offset of the file descriptor, relative to the start of the file.
+    (result $offset $filesize_t)
+  )
+
+  ;; Write to a file descriptor.
+  ;; Note: This is similar to `writev` in POSIX.
+  (func (export "fd_write")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors from which to retrieve data.
+    (param $iovs $iovec_t_array)
+    (result $error $errno_t)
+    ;; The number of bytes written.
+    (result $nwritten $size_t)
+  )
+
+  ;; Create a directory.
+  ;; Note: This is similar to `mkdirat` in POSIX.
+  (func (export "path_create_directory")
+    (param $self $fd_t)
+    ;; The path at which to create the directory.
+    (param $path string)
+    (result $error $errno_t)
+  )
+
+  ;; Return the attributes of a file or directory.
+  ;; Note: This is similar to `stat` in POSIX.
+  (func (export "path_filestat_get")
+    (param $self $fd_t)
+    ;; Flags determining the method of how the path is resolved.
+    (param $flags $lookupflags_t)
+    ;; The path of the file or directory to inspect.
+    (param $path string)
+    (result $error $errno_t)
+    ;; The buffer where the file's attributes are stored.
+    (result $buf $filestat_t)
+  )
+
+  ;; Adjust the timestamps of a file or directory.
+  ;; Note: This is similar to `utimensat` in POSIX.
+  (func (export "path_filestat_set_times")
+    (param $self $fd_t)
+    ;; Flags determining the method of how the path is resolved.
+    (param $flags $lookupflags_t)
+    ;; The path of the file or directory to operate on.
+    (param $path string)
+    ;; The desired values of the data access timestamp.
+    (param $st_atim $timestamp_t)
+    ;; The desired values of the data modification timestamp.
+    (param $st_mtim $timestamp_t)
+    ;; A bitmask indicating which timestamps to adjust.
+    (param $fst_flags $fstflags_t)
+    (result $error $errno_t)
+  )
+
+  ;; Create a hard link.
+  ;; Note: This is similar to `linkat` in POSIX.
+  (func (export "path_link")
+    (param $self $fd_t)
+    ;; Flags determining the method of how the path is resolved.
+    (param $old_flags $lookupflags_t)
+    ;; The source path from which to link.
+    (param $old_path string)
+    ;; The working directory at which the resolution of the new path starts.
+    (param $new_fd $path)
+    ;; The destination path at which to create the hard link.
+    (param $new_path string)
+    (result $error $errno_t)
+  )
+
+  ;; Open a file or directory.
+  ;;
+  ;; The returned file descriptor is not guaranteed to be the lowest-numbered
+  ;; file descriptor not currently open; it is randomized to prevent
+  ;; applications from depending on making assumptions about indexes, since this
+  ;; is error-prone in multi-threaded contexts. The returned file descriptor is
+  ;; guaranteed to be less than 231.
+  ;;
+  ;; Note: This is similar to `openat` in POSIX.
+  (func (export "path_open")
+    (param $self $fd_t)
+    ;; Flags determining the method of how the path is resolved.
+    (param $dirflags $lookupflags_t)
+    ;; The relative path of the file or directory to open, relative to the
+    ;; `dirfd` directory.
+    (param $path string)
+    ;; The method by which to open the file.
+    (param $o_flags $oflags_t)
+    ;; The initial rights of the newly created file descriptor. The
+    ;; implementation is allowed to return a file descriptor with fewer rights
+    ;; than specified, if and only if those rights do not apply to the type of
+    ;; file being opened.
+    ;;
+    ;; The base rights are rights that will apply to operations using the file
+    ;; descriptor itself, while the inheriting rights are rights that apply to
+    ;; file descriptors derived from it.
+    (param $fs_rights_base $rights_t)
+    (param $fs_rights_inherting $rights_t)
+    (result $error $errno_t)
+    ;; The file descriptor of the file that has been opened.
+    (result $opened_fd $fd_t)
+  )
+
+  ;; Read the contents of a symbolic link.
+  ;; Note: This is similar to `readlinkat` in POSIX.
+  (func (export "path_readlink")
+    (param $self $fd_t)
+    ;; The path of the symbolic link from which to read.
+    (param $path)
+    ;; The buffer to which to write the contents of the symbolic link.
+    (param $buf string)
+    (result $error $errno_t)
+    ;; The number of bytes placed in the buffer.
+    (result $bufused $size_t)
+  )
+
+  ;; Remove a directory.
+  ;; Return `__WASI_ENOTEMPTY` if the directory is not empty.
+  ;; Note: This is similar to `unlinkat(fd, path, AT_REMOVEDIR)` in POSIX.
+  (func (export "path_remove_directory")
+    (param $self $fd_t)
+    ;; The path to a directory to remove.
+    (param $path string)
+    (result $error $errno_t)
+  )
+
+  ;; Rename a file or directory.
+  ;; Note: This is similar to `renameat` in POSIX.
+  (func (export "path_rename")
+    (param $self $fd_t)
+    ;; The source path of the file or directory to rename.
+    (param $old_path string)
+    ;; The working directory at which the resolution of the new path starts.
+    (param $new_fd $fd)
+    ;; The destination path to which to rename the file or directory.
+    (param $new_path string)
+    (result $error $errno_t)
+  )
+
+  ;; Create a symbolic link.
+  ;; Note: This is similar to `symlinkat` in POSIX.
+  (func (export "path_symlink")
+    (param $self $fd_t)
+    ;; The contents of the symbolic link.
+    (param $old_path string)
+    ;; The destination path at which to create the symbolic link.
+    (param $new_path string)
+    (result $error $errno_t)
+  )
+
+
+  ;; Unlink a file.
+  ;; Return __WASI_EISDIR if the path refers to a directory.
+  ;; Note: This is similar to `unlinkat(fd, path, 0)` in POSIX.
+  (func (export "path_unlink_file")
+    (param $self $fd_t)
+    ;; The path to a file to unlink.
+    (param $path string)
+    (result $error $errno_t)
+  )
+
+  ;; Concurrently poll for the occurrence of a set of events.
+  (func (export "poll_oneoff")
+    ;; The events to which to subscribe.
+    (param $in $subscription_t)
+    ;; The events that have occurred.
+    (param $out $event_t)
+    ;; Both the number of subscriptions and events.
+    (param $nsubscriptions $size_t)
+    (result $error $errno_t)
+    ;; The number of events stored.
+    (result $nevents $size_t)
+  )
+
+  ;; Terminate the process normally. An exit code of 0 indicates successful
+  ;; termination of the program. The meanings of other values is dependent on
+  ;; the environment.
+  (func (export "proc_exit")
+    ;; The exit code returned by the process.
+    (param $rval $exitcode_t)
+  )
+
+  ;; Send a signal to the process of the calling thread.
+  ;; Note: This is similar to `raise` in POSIX.
+  (func (export "proc_raise")
+    ;; The signal condition to trigger.
+    (param $sig $signal_t)
+    (result $error $errno_t)
+  )
+
+  ;; Temporarily yield execution of the calling thread.
+  ;; Note: This is similar to `sched_yield` in POSIX.
+  (func (export "proc_sched_yield")
+    (result $error $errno_t)
+  )
+
+  ;; Write high-quality random data into a buffer.
+  ;; This function blocks when the implementation is unable to immediately
+  ;; provide sufficient high-quality random data.
+  ;; This function may execute slowly, so when large mounts of random data are
+  ;; required, it's advisable to use this function to seed a pseudo-random
+  ;; number generator, rather than to provide the random data directly.
+  (func (export "random_get")
+    ;; The buffer to fill with random data.
+    (param $buf data)
+    (result $error $errno_t)
+  )
+
+  ;; Receive a message from a socket.
+  ;; Note: This is similar to `recv` in POSIX, though it also supports reading
+  ;; the data into multiple buffers in the manner of `readv`.
+  (func (export "sock_recv")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors to which to store data.
+    (param $ri_data $iovec_t_array)
+    ;; Message flags.
+    (param $ri_flags $riflags_t)
+    (result $error $errno_t)
+    ;; Number of bytes stored in ri_data.
+    (result $ro_datalen $size_t)
+    ;; Message flags.
+    (result $ro_flags $roflags_t)
+  )
+
+  ;; Send a message on a socket.
+  ;; Note: This is similar to `send` in POSIX, though it also supports writing
+  ;; the data from multiple buffers in the manner of `writev`.
+  (func (export "sock_send")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors to which to retrieve data
+    (param $si_data $ciovec_t_array)
+    ;; Message flags.
+    (param $si_flags $siflags_t)
+    (result $error $errno_t)
+    ;; Number of bytes transmitted.
+    (result $so_datalen $size_t)
+  )
+
+  ;; Shut down socket send and receive channels.
+  ;; Note: This is similar to `shutdown` in POSIX.
+  (func (export "sock_shutdown")
+    (param $self $fd_t)
+    ;; Which channels on the socket to shut down.
+    (param $how $sdflags_t)
+    (result $error $errno_t)
+  )
+)

From 33cd953adfed49d4c40d43ac78644bae90045eb3 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Wed, 4 Sep 2019 15:13:53 -0700
Subject: [PATCH 02/26] Update design/wasi_unstable/wasi_unstable.wati

Co-Authored-By: Stefan Junker <steveeJ@users.noreply.github.com>
---
 design/wasi_unstable/wasi_unstable.wati | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/wasi_unstable.wati
index 1dd06791..42c6ba88 100644
--- a/design/wasi_unstable/wasi_unstable.wati
+++ b/design/wasi_unstable/wasi_unstable.wati
@@ -198,7 +198,7 @@
     ;; The right to invoke __wasi_fd_datasync().
     ;;
     ;; If __WASI_RIGHT_PATH_OPEN is set, includes the right to invoke
-    ;` __wasi_path_open() with __WASI_FDFLAG_DSYNC.
+    ;; __wasi_path_open() with __WASI_FDFLAG_DSYNC.
     (flag $RIGHT_FD_DATASYNC)
     ;; The right to invoke __wasi_fd_read() and __wasi_sock_recv().
     ;;

From 402979b26c1c1693028f2bc24043cba525f9285d Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 15 Aug 2019 10:40:46 -0700
Subject: [PATCH 03/26] Give types to iovec_t/ciovec_t's fields.

This replaces the "data" type. It'll be desirable to use higher-level
types to describe what iovec/ciovec do, however to avoid getting into
IDL design questions, for now just use explicit pointer and length
values to keep things simple.
---
 design/wasi_unstable/wasi_unstable.wati | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/wasi_unstable.wati
index 42c6ba88..448c1505 100644
--- a/design/wasi_unstable/wasi_unstable.wati
+++ b/design/wasi_unstable/wasi_unstable.wati
@@ -3,6 +3,7 @@
 ;; Some content here is derived from [CloudABI](https://github.com/NuxiNL/cloudabi).
 
 (typename $size_t u32)
+(typename $uintptr_t u32)
 (typename $string_array (array string))
 
 ;; Non-negative file size or length of a region within a file.
@@ -280,8 +281,8 @@
 (typename $iovec_t
   (struct
     ;; The address and length of the buffer to be filled.
-    (field $buf data)
-    (field $buf_len data)
+    (field $buf $uintptr_t)
+    (field $buf_len $size_t)
   )
 )
 
@@ -289,8 +290,8 @@
 (typename $ciovec_t
   (struct
     ;; The address and length of the buffer to be written.
-    (field $buf data)
-    (field $buf_len data)
+    (field $buf $uintptr_t)
+    (field $buf_len $size_t)
   )
 )
 

From e427e18290fd5380a3e4f9e25c81b738ddcf6ff7 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 15 Aug 2019 10:55:24 -0700
Subject: [PATCH 04/26] Code-quote more things.

---
 design/wasi_unstable/wasi_unstable.wati | 112 ++++++++++++------------
 1 file changed, 56 insertions(+), 56 deletions(-)

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/wasi_unstable.wati
index 448c1505..d0ee446f 100644
--- a/design/wasi_unstable/wasi_unstable.wati
+++ b/design/wasi_unstable/wasi_unstable.wati
@@ -196,82 +196,82 @@
 ;; File descriptor rights, determining which actions may be performed.
 (typename $rights_t
   (flags u64
-    ;; The right to invoke __wasi_fd_datasync().
+    ;; The right to invoke `__wasi_fd_datasync()`.
     ;;
-    ;; If __WASI_RIGHT_PATH_OPEN is set, includes the right to invoke
-    ;; __wasi_path_open() with __WASI_FDFLAG_DSYNC.
+    ;; If `__WASI_RIGHT_PATH_OPEN` is set, includes the right to invoke
+    ;; `__wasi_path_open()` with `__WASI_FDFLAG_DSYNC`.
     (flag $RIGHT_FD_DATASYNC)
-    ;; The right to invoke __wasi_fd_read() and __wasi_sock_recv().
+    ;; The right to invoke `__wasi_fd_read()` and `__wasi_sock_recv()`.
     ;;
-    ;; If __WASI_RIGHT_FD_SEEK is set, includes the right to invoke
-    ;; __wasi_fd_pread().
+    ;; If `__WASI_RIGHT_FD_SEEK` is set, includes the right to invoke
+    ;; `__wasi_fd_pread()`.
     (flag $RIGHT_FD_READ)
-    ;; The right to invoke __wasi_fd_seek(). This flag implies __WASI_RIGHT_FD_TELL.
+    ;; The right to invoke `__wasi_fd_seek()`. This flag implies `__WASI_RIGHT_FD_TELL`.
     (flag $RIGHT_FD_SEEK)
-    ;; The right to invoke __wasi_fd_fdstat_set_flags().
+    ;; The right to invoke `__wasi_fd_fdstat_set_flags()`.
     (flag $RIGHT_FD_FDSTAT_SET_FLAGS)
-    ;; The right to invoke __wasi_fd_sync().
+    ;; The right to invoke `__wasi_fd_sync()`.
     ;;
-    ;; If __WASI_RIGHT_PATH_OPEN is set, includes the right to invoke
-    ;; __wasi_path_open() with __WASI_FDFLAG_RSYNC and __WASI_FDFLAG_DSYNC.
+    ;; If `__WASI_RIGHT_PATH_OPEN` is set, includes the right to invoke
+    ;; `__wasi_path_open()` with `__WASI_FDFLAG_RSYNC` and `__WASI_FDFLAG_DSYNC`.
     (flag $RIGHT_FD_SYNC)
-    ;; The right to invoke __wasi_fd_seek() in such a way that the file offset
-    ;; remains unaltered (i.e., __WASI_WHENCE_CUR with offset zero), or to
-    ;; invoke __wasi_fd_tell().
+    ;; The right to invoke `__wasi_fd_seek()` in such a way that the file offset
+    ;; remains unaltered (i.e., `__WASI_WHENCE_CUR` with offset zero), or to
+    ;; invoke `__wasi_fd_tell()`.
     (flag $RIGHT_FD_TELL)
-    ;; The right to invoke __wasi_fd_write() and __wasi_sock_send().
-    ;; If __WASI_RIGHT_FD_SEEK is set, includes the right to invoke __wasi_fd_pwrite().
+    ;; The right to invoke `__wasi_fd_write()` and `__wasi_sock_send()`.
+    ;; If `__WASI_RIGHT_FD_SEEK` is set, includes the right to invoke `__wasi_fd_pwrite()`.
     (flag $RIGHT_FD_WRITE)
-    ;; The right to invoke __wasi_fd_advise().
+    ;; The right to invoke `__wasi_fd_advise()`.
     (flag $RIGHT_FD_ADVISE)
-    ;; The right to invoke __wasi_fd_allocate().
+    ;; The right to invoke `__wasi_fd_allocate()`.
     (flag $RIGHT_FD_ALLOCATE)
-    ;; The right to invoke __wasi_path_create_directory().
+    ;; The right to invoke `__wasi_path_create_directory()`.
     (flag $RIGHT_PATH_CREATE_DIRECTORY)
-    ;; If __WASI_RIGHT_PATH_OPEN is set, the right to invoke __wasi_path_open() with __WASI_O_CREAT.
+    ;; If `__WASI_RIGHT_PATH_OPEN` is set, the right to invoke `__wasi_path_open()` with `__WASI_O_CREAT`.
     (flag $RIGHT_PATH_CREATE_FILE)
-    ;; The right to invoke __wasi_path_link() with the file descriptor as the source directory.
+    ;; The right to invoke `__wasi_path_link()` with the file descriptor as the source directory.
     (flag $RIGHT_PATH_LINK_SOURCE)
-    ;; The right to invoke __wasi_path_link() with the file descriptor as the target directory.
+    ;; The right to invoke `__wasi_path_link()` with the file descriptor as the target directory.
     (flag $RIGHT_PATH_LINK_TARGET)
-    ;; The right to invoke __wasi_path_open().
+    ;; The right to invoke `__wasi_path_open()`.
     (flag $RIGHT_PATH_OPEN)
-    ;; The right to invoke __wasi_fd_readdir().
+    ;; The right to invoke `__wasi_fd_readdir()`.
     (flag $RIGHT_FD_READDIR)
-    ;; The right to invoke __wasi_path_readlink().
+    ;; The right to invoke `__wasi_path_readlink()`.
     (flag $RIGHT_PATH_READLINK)
-    ;; The right to invoke __wasi_path_rename() with the file descriptor as the source directory.
+    ;; The right to invoke `__wasi_path_rename()` with the file descriptor as the source directory.
     (flag $RIGHT_PATH_RENAME_SOURCE)
-    ;; The right to invoke __wasi_path_rename() with the file descriptor as the target directory.
+    ;; The right to invoke `__wasi_path_rename()` with the file descriptor as the target directory.
     (flag $RIGHT_PATH_RENAME_TARGET)
-    ;; The right to invoke __wasi_path_filestat_get().
+    ;; The right to invoke `__wasi_path_filestat_get()`.
     (flag $RIGHT_PATH_FILESTAT_GET)
-    ;; The right to change a file's size (there is no __wasi_path_filestat_set_size()).
-    ;; If __WASI_RIGHT_PATH_OPEN is set, includes the right to invoke __wasi_path_open() with __WASI_O_TRUNC.
+    ;; The right to change a file's size (there is no `__wasi_path_filestat_set_size()`).
+    ;; If `__WASI_RIGHT_PATH_OPEN` is set, includes the right to invoke `__wasi_path_open()` with `__WASI_O_TRUNC`.
     (flag $RIGHT_PATH_FILESTAT_SET_SIZE)
-    ;; The right to invoke __wasi_path_filestat_set_times().
+    ;; The right to invoke `__wasi_path_filestat_set_times()`.
     (flag $RIGHT_PATH_FILESTAT_SET_TIMES)
-    ;; The right to invoke __wasi_fd_filestat_get().
+    ;; The right to invoke `__wasi_fd_filestat_get()`.
     (flag $RIGHT_FD_FILESTAT_GET)
-    ;; The right to invoke __wasi_fd_filestat_set_size().
+    ;; The right to invoke `__wasi_fd_filestat_set_size()`.
     (flag $RIGHT_FD_FILESTAT_SET_SIZE)
-    ;; The right to invoke __wasi_fd_filestat_set_times().
+    ;; The right to invoke `__wasi_fd_filestat_set_times()`.
     (flag $RIGHT_FD_FILESTAT_SET_TIMES)
-    ;; The right to invoke __wasi_path_symlink().
+    ;; The right to invoke `__wasi_path_symlink()`.
     (flag $RIGHT_PATH_SYMLINK)
-    ;; The right to invoke __wasi_path_unlink_file().
+    ;; The right to invoke `__wasi_path_unlink_file()`.
     (flag $RIGHT_PATH_UNLINK_FILE)
-    ;; The right to invoke __wasi_path_remove_directory().
+    ;; The right to invoke `__wasi_path_remove_directory()`.
     (flag $RIGHT_PATH_REMOVE_DIRECTORY)
-    ;; If __WASI_RIGHT_FD_READ is set, includes the right to invoke __wasi_poll_oneoff() to subscribe to __WASI_EVENTTYPE_FD_READ.
-    ;; If __WASI_RIGHT_FD_WRITE is set, includes the right to invoke __wasi_poll_oneoff() to subscribe to __WASI_EVENTTYPE_FD_WRITE.
+    ;; If `__WASI_RIGHT_FD_READ` is set, includes the right to invoke `__wasi_poll_oneoff()` to subscribe to `__WASI_EVENTTYPE_FD_READ`.
+    ;; If `__WASI_RIGHT_FD_WRITE` is set, includes the right to invoke `__wasi_poll_oneoff()` to subscribe to `__WASI_EVENTTYPE_FD_WRITE`.
     (flag $RIGHT_POLL_FD_READWRITE)
-    ;; The right to invoke __wasi_sock_shutdown().
+    ;; The right to invoke `__wasi_sock_shutdown()`.
     (flag $RIGHT_SOCK_SHUTDOWN)
   )
 )
 
-;; a file descriptor index
+;; A file descriptor index.
 (typename $fd_t u32)
 
 (typename $iovec_t_array (array $iovec_t))
@@ -377,7 +377,7 @@
     (field $fs_rights_base $rights_t)
     ;; Maximum set of rights that may be installed on new file descriptors that
     ;; are created through this file descriptor, e.g., through
-    ;; __wasi_path_open().
+    ;; `__wasi_path_open()`.
     (field $fs_rights_inheriting $rights_t)
   )
 )
@@ -414,11 +414,11 @@
   (flags u16
     ;; Adjust the last data access timestamp to the value stored in __wasi_filestat_t::st_atim.
     (flag $FILESTAT_SET_ATIM)
-    ;; Adjust the last data access timestamp to the time of clock __WASI_CLOCK_REALTIME.
+    ;; Adjust the last data access timestamp to the time of clock `__WASI_CLOCK_REALTIME`.
     (flag $FILESTAT_SET_ATIM_NOW)
     ;; Adjust the last data modification timestamp to the value stored in __wasi_filestat_t::st_mtim.
     (flag $FILESTAT_SET_MTIM)
-    ;; Adjust the last data modification timestamp to the time of clock __WASI_CLOCK_REALTIME.
+    ;; Adjust the last data modification timestamp to the time of clock `__WASI_CLOCK_REALTIME`.
     (flag $FILESTAT_SET_MTIM_NOW)
   )
 )
@@ -434,7 +434,7 @@
   )
 )
 
-;; Open flags used by __wasi_path_open().
+;; Open flags used by `__wasi_path_open()`.
 (typename $oflags_t
   (flags u16
     ;; Create file if it does not exist.
@@ -487,7 +487,7 @@
     (field $type $eventtype_t)
     (field $u
       (typename union
-        ;; When type is __WASI_EVENTTYPE_FD_READ or __WASI_EVENTTYPE_FD_WRITE:
+        ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
         (field $fd_readwrite
           (typename stuct
             ;; The number of bytes available for reading or writing.
@@ -502,7 +502,7 @@
   )
 )
 
-;; The state of the file descriptor subscribed to with __WASI_EVENTTYPE_FD_READ or __WASI_EVENTTYPE_FD_WRITE.
+;; The state of the file descriptor subscribed to with `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`.
 (typename $eventrwflags_t
   (flags u16
     ;; The peer of this socket has closed or disconnected.
@@ -544,7 +544,7 @@
     (field
       (type
         (union
-          ;; When type is __WASI_EVENTTYPE_CLOCK
+          ;; When type is `__WASI_EVENTTYPE_CLOCK`:
           (field $clock
             (typename
               (struct
@@ -560,7 +560,7 @@
               )
             )
           )
-          ;; When type is __WASI_EVENTTYPE_FD_READ or __WASI_EVENTTYPE_FD_WRITE:
+          ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
           (field $fd_readwrite
             (type
               (struct
@@ -662,7 +662,7 @@
   )
 )
 
-;; Flags provided to __wasi_sock_recv().
+;; Flags provided to `__wasi_sock_recv()`.
 (typename $riflags_t
   (flags u16
     ;; Returns the message without removing it from the socket's receive queue.
@@ -672,15 +672,15 @@
   )
 )
 
-;; Flags returned by __wasi_sock_recv().
+;; Flags returned by `__wasi_sock_recv()`.
 (typename $roflags_t
   (flags u16
-    ;; Returned by __wasi_sock_recv(): Message data has been truncated.
+    ;; Returned by `__wasi_sock_recv()`: Message data has been truncated.
     (flag $SOCK_RECV_DATA_TRUNCATED)
   )
 )
 
-;; Flags provided to __wasi_sock_send(). As there are currently no flags defined, it must be set to zero.
+;; Flags provided to `__wasi_sock_send()`. As there are currently no flags defined, it must be set to zero.
 (typename $siflags_t u16)
 
 ;; Which channels on a socket to shut down.
@@ -925,8 +925,8 @@
   )
 
   ;; Atomically replace a file descriptor by renumbering another file descriptor.
-  ;; Due to the strong focus on thread safety, this environment does not provide a mechanism to duplicate or renumber a file descriptor to an arbitrary number, like dup2(). This would be prone to race conditions, as an actual file descriptor with the same number could be allocated by a different thread at the same time.
-  ;; This function provides a way to atomically renumber file descriptors, which would disappear if dup2() were to be removed entirely.
+  ;; Due to the strong focus on thread safety, this environment does not provide a mechanism to duplicate or renumber a file descriptor to an arbitrary number, like `dup2()`. This would be prone to race conditions, as an actual file descriptor with the same number could be allocated by a different thread at the same time.
+  ;; This function provides a way to atomically renumber file descriptors, which would disappear if `dup2()` were to be removed entirely.
   (func (export "fd_renumber")
     (param $self $fd_t)
     ;; The file descriptor to overwrite.
@@ -1110,7 +1110,7 @@
 
 
   ;; Unlink a file.
-  ;; Return __WASI_EISDIR if the path refers to a directory.
+  ;; Return `__WASI_EISDIR` if the path refers to a directory.
   ;; Note: This is similar to `unlinkat(fd, path, 0)` in POSIX.
   (func (export "path_unlink_file")
     (param $self $fd_t)

From cb498da2de26a4ca5d39d8fac29eb1ad1fbf3b0c Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 15 Aug 2019 10:57:25 -0700
Subject: [PATCH 05/26] Remove the $else field of a union.

---
 design/wasi_unstable/wasi_unstable.wati | 1 -
 1 file changed, 1 deletion(-)

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/wasi_unstable.wati
index d0ee446f..0570345c 100644
--- a/design/wasi_unstable/wasi_unstable.wati
+++ b/design/wasi_unstable/wasi_unstable.wati
@@ -496,7 +496,6 @@
             (field $flags $eventrwflags_t)
           )
         )
-        (field $else Null)
       )
     )
   )

From 80a41155ae9ef3c629ce6a567696cea1176fb1ef Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 15 Aug 2019 10:59:09 -0700
Subject: [PATCH 06/26] Clean up a few more `(type ...)` and `(typename ...)`
 constructs.

Only use `(typename ...)` to declare named types; don't use it for
inline types.
---
 design/wasi_unstable/wasi_unstable.wati | 48 +++++++++++--------------
 1 file changed, 21 insertions(+), 27 deletions(-)

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/wasi_unstable.wati
index 0570345c..43805482 100644
--- a/design/wasi_unstable/wasi_unstable.wati
+++ b/design/wasi_unstable/wasi_unstable.wati
@@ -486,10 +486,10 @@
     ;; The type of the event that occurred.
     (field $type $eventtype_t)
     (field $u
-      (typename union
+      (union
         ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
         (field $fd_readwrite
-          (typename stuct
+          (struct
             ;; The number of bytes available for reading or writing.
             (field $nbytes $filesize_t)
             ;; The state of the file descriptor.
@@ -541,32 +541,26 @@
     ;; The type of the event to which to subscribe.
     (field $type $eventtype_t)
     (field
-      (type
-        (union
-          ;; When type is `__WASI_EVENTTYPE_CLOCK`:
-          (field $clock
-            (typename
-              (struct
-                ;; The user-defined unique identifier of the clock.
-                (field $identifier $userdata_t)
-                ;; The clock against which to compare the timestamp.
-                (field $clock_id $clockid_t)
-                ;; The absolute or relative timestamp.
-                (field $timeout $timestamp_t)
-                ;; The amount of time that the implementation may wait additionally to coalesce with other events.
-                ;; Flags specifying whether the timeout is absolute or relative
-                (field $precision $timestamp_t)
-              )
-            )
+      (union
+        ;; When type is `__WASI_EVENTTYPE_CLOCK`:
+        (field $clock
+          (struct
+            ;; The user-defined unique identifier of the clock.
+            (field $identifier $userdata_t)
+            ;; The clock against which to compare the timestamp.
+            (field $clock_id $clockid_t)
+            ;; The absolute or relative timestamp.
+            (field $timeout $timestamp_t)
+            ;; The amount of time that the implementation may wait additionally to coalesce with other events.
+            ;; Flags specifying whether the timeout is absolute or relative
+            (field $precision $timestamp_t)
           )
-          ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
-          (field $fd_readwrite
-            (type
-              (struct
-                ;; The file descriptor on which to wait for it to become ready for reading or writing.
-                (field $file_descriptor $fd_t)
-              )
-            )
+        )
+        ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
+        (field $fd_readwrite
+          (struct
+            ;; The file descriptor on which to wait for it to become ready for reading or writing.
+            (field $file_descriptor $fd_t)
           )
         )
       )

From 2ddd38a86389bf995c4370f7397ac723e749073f Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 15 Aug 2019 11:01:21 -0700
Subject: [PATCH 07/26] Wrap some long lines.

---
 design/wasi_unstable/wasi_unstable.wati | 45 ++++++++++++++++++-------
 1 file changed, 32 insertions(+), 13 deletions(-)

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/wasi_unstable.wati
index 43805482..a2ba1e3e 100644
--- a/design/wasi_unstable/wasi_unstable.wati
+++ b/design/wasi_unstable/wasi_unstable.wati
@@ -230,9 +230,11 @@
     (flag $RIGHT_PATH_CREATE_DIRECTORY)
     ;; If `__WASI_RIGHT_PATH_OPEN` is set, the right to invoke `__wasi_path_open()` with `__WASI_O_CREAT`.
     (flag $RIGHT_PATH_CREATE_FILE)
-    ;; The right to invoke `__wasi_path_link()` with the file descriptor as the source directory.
+    ;; The right to invoke `__wasi_path_link()` with the file descriptor as the
+    ;; source directory.
     (flag $RIGHT_PATH_LINK_SOURCE)
-    ;; The right to invoke `__wasi_path_link()` with the file descriptor as the target directory.
+    ;; The right to invoke `__wasi_path_link()` with the file descriptor as the
+    ;; target directory.
     (flag $RIGHT_PATH_LINK_TARGET)
     ;; The right to invoke `__wasi_path_open()`.
     (flag $RIGHT_PATH_OPEN)
@@ -473,7 +475,8 @@
   )
 )
 
-;; User-provided value that may be attached to objects that is retained when extracted from the implementation.
+;; User-provided value that may be attached to objects that is retained when
+;; extracted from the implementation.
 (typename $userdata_t u64)
 
 ;; An event that occurred.
@@ -501,7 +504,8 @@
   )
 )
 
-;; The state of the file descriptor subscribed to with `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`.
+;; The state of the file descriptor subscribed to with
+;; `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`.
 (typename $eventrwflags_t
   (flags u16
     ;; The peer of this socket has closed or disconnected.
@@ -512,16 +516,20 @@
 ;; Type of a subscription to an event or its occurrence.
 (typename $eventtype_t
   (flags u8
-    ;; The time value of clock __wasi_subscription_t::u.clock.clock_id has reached timestamp __wasi_subscription_t::u.clock.timeout.
+    ;; The time value of clock __wasi_subscription_t::u.clock.clock_id has
+    ;; reached timestamp __wasi_subscription_t::u.clock.timeout.
     (flag $EVENTTYPE_CLOCK)
-    ;; File descriptor __wasi_subscription_t::u.fd_readwrite.fd has data available for reading. This event always triggers for regular files.
+    ;; File descriptor __wasi_subscription_t::u.fd_readwrite.fd has data
+    ;; available for reading. This event always triggers for regular files.
     (flag $EVENTTYPE_FD_READ)
-    ;; File descriptor __wasi_subscription_t::u.fd_readwrite.fd has capacity available for writing. This event always triggers for regular files.
+    ;; File descriptor __wasi_subscription_t::u.fd_readwrite.fd has capacity
+    ;; available for writing. This event always triggers for regular files.
     (flag $EVENTTYPE_FD_WRITE)
   )
 )
 
-;; Flags determining how to interpret the timestamp provided in __wasi_subscription_t::u.clock.timeout.
+;; Flags determining how to interpret the timestamp provided in
+;; __wasi_subscription_t::u.clock.timeout.
 (typename $subclockflags_t
   (flags u16
     ;; If set, treat the timestamp provided in
@@ -536,7 +544,8 @@
 ;; Subscription to an event.
 (typename $subscription_t
   (struct
-    ;; User-provided value that is attached to the subscription in the implementation and returned through __wasi_event_t::userdata.
+    ;; User-provided value that is attached to the subscription in the
+    ;; implementation and returned through __wasi_event_t::userdata.
     (field $userdata $userdata_t)
     ;; The type of the event to which to subscribe.
     (field $type $eventtype_t)
@@ -551,7 +560,9 @@
             (field $clock_id $clockid_t)
             ;; The absolute or relative timestamp.
             (field $timeout $timestamp_t)
-            ;; The amount of time that the implementation may wait additionally to coalesce with other events.
+            ;; The amount of time that the implementation may wait additionally
+            ;; to coalesce with other events.
+            ;;
             ;; Flags specifying whether the timeout is absolute or relative
             (field $precision $timestamp_t)
           )
@@ -673,7 +684,8 @@
   )
 )
 
-;; Flags provided to `__wasi_sock_send()`. As there are currently no flags defined, it must be set to zero.
+;; Flags provided to `__wasi_sock_send()`. As there are currently no flags
+;; defined, it must be set to zero.
 (typename $siflags_t u16)
 
 ;; Which channels on a socket to shut down.
@@ -918,8 +930,15 @@
   )
 
   ;; Atomically replace a file descriptor by renumbering another file descriptor.
-  ;; Due to the strong focus on thread safety, this environment does not provide a mechanism to duplicate or renumber a file descriptor to an arbitrary number, like `dup2()`. This would be prone to race conditions, as an actual file descriptor with the same number could be allocated by a different thread at the same time.
-  ;; This function provides a way to atomically renumber file descriptors, which would disappear if `dup2()` were to be removed entirely.
+  ;;
+  ;; Due to the strong focus on thread safety, this environment does not provide
+  ;; a mechanism to duplicate or renumber a file descriptor to an arbitrary
+  ;; number, like `dup2()`. This would be prone to race conditions, as an actual
+  ;; file descriptor with the same number could be allocated by a different
+  ;; thread at the same time.
+  ;;
+  ;; This function provides a way to atomically renumber file descriptors, which
+  ;; would disappear if `dup2()` were to be removed entirely.
   (func (export "fd_renumber")
     (param $self $fd_t)
     ;; The file descriptor to overwrite.

From c5d74fd01f868735e4ea522060b575d892873786 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 15 Aug 2019 11:05:15 -0700
Subject: [PATCH 08/26] Fix field syntax.

---
 design/wasi_unstable/wasi_unstable.wati | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/wasi_unstable.wati
index a2ba1e3e..63897449 100644
--- a/design/wasi_unstable/wasi_unstable.wati
+++ b/design/wasi_unstable/wasi_unstable.wati
@@ -549,7 +549,7 @@
     (field $userdata $userdata_t)
     ;; The type of the event to which to subscribe.
     (field $type $eventtype_t)
-    (field
+    (field $u
       (union
         ;; When type is `__WASI_EVENTTYPE_CLOCK`:
         (field $clock

From 234233d6a6ea491bb7af7d1a7cddc3c38603d896 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 15 Aug 2019 11:05:23 -0700
Subject: [PATCH 09/26] Fix exponentiation syntax in a comment.

---
 design/wasi_unstable/wasi_unstable.wati | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/wasi_unstable.wati
index 63897449..5a816ada 100644
--- a/design/wasi_unstable/wasi_unstable.wati
+++ b/design/wasi_unstable/wasi_unstable.wati
@@ -1046,7 +1046,7 @@
   ;; file descriptor not currently open; it is randomized to prevent
   ;; applications from depending on making assumptions about indexes, since this
   ;; is error-prone in multi-threaded contexts. The returned file descriptor is
-  ;; guaranteed to be less than 231.
+  ;; guaranteed to be less than 2**31.
   ;;
   ;; Note: This is similar to `openat` in POSIX.
   (func (export "path_open")

From e0d5f4005b22eeb3eddc3759781e40f65696af0a Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 22 Aug 2019 10:48:08 -0700
Subject: [PATCH 10/26] Rename .wati to .widl, use more interface-types syntax,
 and move types to a separate file.

---
 .../{wasi_unstable.wati => typenames.widl}    | 522 +-----------------
 design/wasi_unstable/wasi_unstable.widl       | 519 +++++++++++++++++
 2 files changed, 520 insertions(+), 521 deletions(-)
 rename design/wasi_unstable/{wasi_unstable.wati => typenames.widl} (54%)
 create mode 100644 design/wasi_unstable/wasi_unstable.widl

diff --git a/design/wasi_unstable/wasi_unstable.wati b/design/wasi_unstable/typenames.widl
similarity index 54%
rename from design/wasi_unstable/wasi_unstable.wati
rename to design/wasi_unstable/typenames.widl
index 5a816ada..df97290e 100644
--- a/design/wasi_unstable/wasi_unstable.wati
+++ b/design/wasi_unstable/typenames.widl
@@ -1,4 +1,4 @@
-;; The wasi_unstable module type.
+;; Type names used by the wasi_unstable module type.
 ;;
 ;; Some content here is derived from [CloudABI](https://github.com/NuxiNL/cloudabi).
 
@@ -697,523 +697,3 @@
     (flag $SHUT_WR)
   )
 )
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;
-;; The wasi_unstable moduletype.
-;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-(moduletype $wasi_unstable
-  ;; Linear memory used by the program.
-  (import "memory" (memory))
-
-  ;; The program entry point.
-  (import "_start" (func))
-
-  ;; Read command-line argument data.
-  ;; The size of the array should match that returned by `wasi_args_sizes_get()`
-  (func (export "args_get")
-    (result $error $errno_t)
-    (result $argv $string_array)
-  )
-  ;; Return command-line argument data sizes.
-  (func (export "args_sizes_get")
-    (result $error $errno_t)
-    ;; The number of arguments.
-    (result $argc $size_t)
-    ;; The size of the argument string data.
-    (result $argv_buf_size $size_t)
-  )
-
-  ;; Read environment variable data.
-  ;; The sizes of the buffers should match that returned by `environ.sizes_get()`.
-  (func (export "environ_get")
-    (result $error $errno_t)
-    (result $argv $string_array)
-  )
-  ;; Return command-line argument data sizes.
-  (func (export "environ_sizes_get")
-    ;; The number of arguments.
-    (result $argc $size_t)
-    ;; The size of the argument string data.
-    (result $argv_buf_size $size_t)
-  )
-
-  ;; Return the resolution of a clock.
-  ;; Implementations are required to provide a non-zero value for supported clocks. For unsupported clocks, return `WASI_EINVAL`
-  ;; Note: This is similar to `clock_getres` in POSIX.
-  (func (export "clock_res_get")
-    (result $error $errno_t)
-    ;; The clock for which to return the resolution.
-    (param $clock_id $clockid_t)
-    ;; The resolution of the clock.
-    (result $resolution $timestamp_t)
-  )
-  ;; Return the time value of a clock.
-  ;; Note: This is similar to `clock_gettime` in POSIX.
-  (func (export "clock_time_get")
-    ;; The clock for which to return the time.
-    (param $clock_id $clockid_t)
-    ;; The maximum lag (exclusive) that the returned time value may have, compared to its actual value.
-    (param $precision $timestamp_t)
-    (result $error $errno_t)
-    ;; The time value of the clock.
-    (result $time $timestamp_t)
-  )
-
-  ;; Provide file advisory information on a file descriptor.
-  ;; Note: This is similar to `posix_fadvise` in POSIX.
-  (func (export "fd_advise")
-    (param $self $fd_t)
-    (param $offset $filesize_t) ;; The offset within the file to which the advisory applies.
-    (param $len $filesize_t) ;; The length of the region to which the advisory applies.
-    (param $advice $advice_t) ;; The advice.
-    (result $error $errno_t)
-  )
-
-  ;; Force the allocation of space in a file.
-  ;; Note: This is similar to `posix_fallocate` in POSIX.
-  (func (export "fd_allocate")
-    (param $self $fd_t)
-    ;; The offset at which to start the allocation.
-    (param $offset $filesize_t)
-    ;; The length of the area that is allocated.
-    (param $len $filesize_t)
-    (result $error $errno_t)
-  )
-
-  ;; Close a file descriptor.
-  ;; Note: This is similar to `close` in POSIX.
-  (func (export "fd_close")
-    (param $self $fd_t)
-    (result $error $errno_t)
-  )
-
-  ;; Synchronize the data of a file to disk.
-  ;; Note: This is similar to `fdatasync` in POSIX.
-  (func (export "fd_datasync")
-    (param $self $fd_t)
-    (result $error $errno_t)
-  )
-
-  ;; Get the attributes of a file descriptor.
-  ;; Note: This returns similar flags to `fsync(fd, F_GETFL)` in POSIX, as well as additional fields.
-  (func (export "fd_fdstat_get")
-    (param $self $fd_t)
-    (result $error $errno_t)
-    ;; The buffer where the file descriptor's attributes are stored.
-    (result $fdstat_t)
-  )
-
-  ;; Adjust the flags associated with a file descriptor.
-  ;; Note: This is similar to `fcntl(fd, F_SETFL, flags)` in POSIX.
-  (func (export "fd_fdstat_set_flags")
-    (param $self $fd_t)
-    ;; The desired values of the file descriptor flags.
-    (param $flags $fdflags)
-    (result $error $errno_t)
-  )
-
-  ;;  Adjust the rights associated with a file descriptor.
-  ;; This can only be used to remove rights, and returns `ENOTCAPABLE` if called in a way that would attempt to add rights
-  (func (export "fd_fdstat_set_rights")
-    (param $self $fd_t)
-    ;; The desired rights of the file descriptor.
-    (param $fs_rights_base $rights_t)
-    (param $fs_rights_inheriting $rights_t)
-    (result $error $errno_t)
-  )
-
-  ;; Return the attributes of an open file.
-  (func (export "fd_filestat_get")
-    (param $self $fd_t)
-    (result $error $errno_t)
-    ;; The buffer where the file's attributes are stored.
-    (result $fs_rights_base $rights_t)
-  )
-
-  ;; Adjust the size of an open file. If this increases the file's size, the extra bytes are filled with zeros.
-  ;; Note: This is similar to `ftruncate` in POSIX.
-  (func (export "fd_filestat_set_size")
-    (param $self $fd_t)
-    ;; The desired file size.
-    (param $st_size $filesize_t)
-    (result $error $errno_t)
-  )
-
-  ;; Adjust the timestamps of an open file or directory.
-  ;; Note: This is similar to `futimens` in POSIX.
-  (func (export "fd_filestat_set_times")
-    (param $self $fd_t)
-    ;; The desired values of the data access timestamp.
-    (param $st_atim $timestamp_t)
-    ;; The desired values of the data modification timestamp.
-    (param $st_mtim $timestamp_t)
-    ;; A bitmask indicating which timestamps to adjust.
-    (param $fst_flags $fstflags_t)
-    (result $error $errno_t)
-  )
-
-  ;; Read from a file descriptor, without using and updating the file descriptor's offset.
-  ;; Note: This is similar to `preadv` in POSIX.
-  (func (export "fd_pread")
-    (param $self $fd_t)
-    ;; List of scatter/gather vectors in which to store data.
-    (param $iovs $iovec_t_array)
-    ;; The offset within the file at which to read.
-    (param $offset $filesize_t)
-    (result $error $errno_t)
-    ;; The number of bytes read.
-    (result $nread $size_t)
-  )
-
-  ;; Return a description of the given preopened file descriptor.
-  (func (export "fd_prestat_get")
-    (param $self $fd_t)
-    (result $error $errno_t)
-    ;; The buffer where the description is stored.
-    (result $buf $prestat_t)
-  )
-
-  ;; Return a description of the given preopened file descriptor.
-  (func (export "fd_prestat_dir_name")
-    (param $self $fd_t)
-    ;; A buffer into which to write the preopened directory name.
-    (param $path string)
-    (result $error $errno_t)
-  )
-
-  ;; Write to a file descriptor, without using and updating the file descriptor's offset.
-  ;; Note: This is similar to `pwritev` in POSIX.
-  (func (export "fd_pwrite")
-    (param $self $fd_t)
-    ;; List of scatter/gather vectors from which to retrieve data.
-    (param $iovs $iovec_t_array)
-    ;; The offset within the file at which to write.
-    (param $offset $filesize_t)
-    (result $error $errno_t)
-    ;; The number of bytes written.
-    (result $nwritten $size_t)
-  )
-
-  ;; Read from a file descriptor.
-  ;; Note: This is similar to `readv` in POSIX.
-  (func (export "fd_read")
-    (param $self $fd_t)
-    ;; List of scatter/gather vectors to which to store data.
-    (param $iovs $iovec_t_array)
-    (result $error $errno_t)
-    ;; The number of bytes read.
-    (result $nread $size_t)
-  )
-
-  ;; Read directory entries from a directory.
-  ;; When successful, the contents of the output buffer consist of a sequence of
-  ;; directory entries. Each directory entry consists of a dirent_t object,
-  ;; followed by dirent_t::d_namlen bytes holding the name of the directory
-  ;; entry.
-  ;;
-  ;; This function fills the output buffer as much as possible, potentially
-  ;; truncating the last directory entry. This allows the caller to grow its
-  ;; read buffer size in case it's too small to fit a single large directory
-  ;; entry, or skip the oversized directory entry.
-  (func (export "fd_readdir")
-    (param $self $fd_t)
-    ;; The buffer where directory entries are stored
-    (param $buf data)
-    ;; The location within the directory to start reading
-    (param $cookie $dircookie_t)
-    (result $error $errno_t)
-    ;; The number of bytes stored in the read buffer. If less than the size of the read buffer, the end of the directory has been reached.
-    (result $bufused $size_t)
-  )
-
-  ;; Atomically replace a file descriptor by renumbering another file descriptor.
-  ;;
-  ;; Due to the strong focus on thread safety, this environment does not provide
-  ;; a mechanism to duplicate or renumber a file descriptor to an arbitrary
-  ;; number, like `dup2()`. This would be prone to race conditions, as an actual
-  ;; file descriptor with the same number could be allocated by a different
-  ;; thread at the same time.
-  ;;
-  ;; This function provides a way to atomically renumber file descriptors, which
-  ;; would disappear if `dup2()` were to be removed entirely.
-  (func (export "fd_renumber")
-    (param $self $fd_t)
-    ;; The file descriptor to overwrite.
-    (param $to $fd_t)
-    (result $error $errno_t)
-  )
-
-  ;; Move the offset of a file descriptor.
-  ;; Note: This is similar to `lseek` in POSIX.
-  (func (export "fd_seek")
-    (param $self $fd_t)
-    ;; The number of bytes to move.
-    (param $offset $filedelta_t)
-    ;; The base from which the offset is relative.
-    (param $whence $whence_t)
-    (result $error $errno_t)
-    ;; The new offset of the file descriptor, relative to the start of the file.
-    (result $newoffset $filesize_t)
-  )
-
-  ;; Synchronize the data and metadata of a file to disk.
-  ;; Note: This is similar to `fsync` in POSIX.
-  (func (export "fd_sync")
-    (param $self $fd_t)
-    (result $error $errno_t)
-  )
-
-  ;; Return the current offset of a file descriptor.
-  ;; Note: This is similar to `lseek(fd, 0, SEEK_CUR)` in POSIX.
-  (func (export "fd_tell")
-    (param $self $fd_t)
-    (result $error $errno_t)
-    ;; The current offset of the file descriptor, relative to the start of the file.
-    (result $offset $filesize_t)
-  )
-
-  ;; Write to a file descriptor.
-  ;; Note: This is similar to `writev` in POSIX.
-  (func (export "fd_write")
-    (param $self $fd_t)
-    ;; List of scatter/gather vectors from which to retrieve data.
-    (param $iovs $iovec_t_array)
-    (result $error $errno_t)
-    ;; The number of bytes written.
-    (result $nwritten $size_t)
-  )
-
-  ;; Create a directory.
-  ;; Note: This is similar to `mkdirat` in POSIX.
-  (func (export "path_create_directory")
-    (param $self $fd_t)
-    ;; The path at which to create the directory.
-    (param $path string)
-    (result $error $errno_t)
-  )
-
-  ;; Return the attributes of a file or directory.
-  ;; Note: This is similar to `stat` in POSIX.
-  (func (export "path_filestat_get")
-    (param $self $fd_t)
-    ;; Flags determining the method of how the path is resolved.
-    (param $flags $lookupflags_t)
-    ;; The path of the file or directory to inspect.
-    (param $path string)
-    (result $error $errno_t)
-    ;; The buffer where the file's attributes are stored.
-    (result $buf $filestat_t)
-  )
-
-  ;; Adjust the timestamps of a file or directory.
-  ;; Note: This is similar to `utimensat` in POSIX.
-  (func (export "path_filestat_set_times")
-    (param $self $fd_t)
-    ;; Flags determining the method of how the path is resolved.
-    (param $flags $lookupflags_t)
-    ;; The path of the file or directory to operate on.
-    (param $path string)
-    ;; The desired values of the data access timestamp.
-    (param $st_atim $timestamp_t)
-    ;; The desired values of the data modification timestamp.
-    (param $st_mtim $timestamp_t)
-    ;; A bitmask indicating which timestamps to adjust.
-    (param $fst_flags $fstflags_t)
-    (result $error $errno_t)
-  )
-
-  ;; Create a hard link.
-  ;; Note: This is similar to `linkat` in POSIX.
-  (func (export "path_link")
-    (param $self $fd_t)
-    ;; Flags determining the method of how the path is resolved.
-    (param $old_flags $lookupflags_t)
-    ;; The source path from which to link.
-    (param $old_path string)
-    ;; The working directory at which the resolution of the new path starts.
-    (param $new_fd $path)
-    ;; The destination path at which to create the hard link.
-    (param $new_path string)
-    (result $error $errno_t)
-  )
-
-  ;; Open a file or directory.
-  ;;
-  ;; The returned file descriptor is not guaranteed to be the lowest-numbered
-  ;; file descriptor not currently open; it is randomized to prevent
-  ;; applications from depending on making assumptions about indexes, since this
-  ;; is error-prone in multi-threaded contexts. The returned file descriptor is
-  ;; guaranteed to be less than 2**31.
-  ;;
-  ;; Note: This is similar to `openat` in POSIX.
-  (func (export "path_open")
-    (param $self $fd_t)
-    ;; Flags determining the method of how the path is resolved.
-    (param $dirflags $lookupflags_t)
-    ;; The relative path of the file or directory to open, relative to the
-    ;; `dirfd` directory.
-    (param $path string)
-    ;; The method by which to open the file.
-    (param $o_flags $oflags_t)
-    ;; The initial rights of the newly created file descriptor. The
-    ;; implementation is allowed to return a file descriptor with fewer rights
-    ;; than specified, if and only if those rights do not apply to the type of
-    ;; file being opened.
-    ;;
-    ;; The base rights are rights that will apply to operations using the file
-    ;; descriptor itself, while the inheriting rights are rights that apply to
-    ;; file descriptors derived from it.
-    (param $fs_rights_base $rights_t)
-    (param $fs_rights_inherting $rights_t)
-    (result $error $errno_t)
-    ;; The file descriptor of the file that has been opened.
-    (result $opened_fd $fd_t)
-  )
-
-  ;; Read the contents of a symbolic link.
-  ;; Note: This is similar to `readlinkat` in POSIX.
-  (func (export "path_readlink")
-    (param $self $fd_t)
-    ;; The path of the symbolic link from which to read.
-    (param $path)
-    ;; The buffer to which to write the contents of the symbolic link.
-    (param $buf string)
-    (result $error $errno_t)
-    ;; The number of bytes placed in the buffer.
-    (result $bufused $size_t)
-  )
-
-  ;; Remove a directory.
-  ;; Return `__WASI_ENOTEMPTY` if the directory is not empty.
-  ;; Note: This is similar to `unlinkat(fd, path, AT_REMOVEDIR)` in POSIX.
-  (func (export "path_remove_directory")
-    (param $self $fd_t)
-    ;; The path to a directory to remove.
-    (param $path string)
-    (result $error $errno_t)
-  )
-
-  ;; Rename a file or directory.
-  ;; Note: This is similar to `renameat` in POSIX.
-  (func (export "path_rename")
-    (param $self $fd_t)
-    ;; The source path of the file or directory to rename.
-    (param $old_path string)
-    ;; The working directory at which the resolution of the new path starts.
-    (param $new_fd $fd)
-    ;; The destination path to which to rename the file or directory.
-    (param $new_path string)
-    (result $error $errno_t)
-  )
-
-  ;; Create a symbolic link.
-  ;; Note: This is similar to `symlinkat` in POSIX.
-  (func (export "path_symlink")
-    (param $self $fd_t)
-    ;; The contents of the symbolic link.
-    (param $old_path string)
-    ;; The destination path at which to create the symbolic link.
-    (param $new_path string)
-    (result $error $errno_t)
-  )
-
-
-  ;; Unlink a file.
-  ;; Return `__WASI_EISDIR` if the path refers to a directory.
-  ;; Note: This is similar to `unlinkat(fd, path, 0)` in POSIX.
-  (func (export "path_unlink_file")
-    (param $self $fd_t)
-    ;; The path to a file to unlink.
-    (param $path string)
-    (result $error $errno_t)
-  )
-
-  ;; Concurrently poll for the occurrence of a set of events.
-  (func (export "poll_oneoff")
-    ;; The events to which to subscribe.
-    (param $in $subscription_t)
-    ;; The events that have occurred.
-    (param $out $event_t)
-    ;; Both the number of subscriptions and events.
-    (param $nsubscriptions $size_t)
-    (result $error $errno_t)
-    ;; The number of events stored.
-    (result $nevents $size_t)
-  )
-
-  ;; Terminate the process normally. An exit code of 0 indicates successful
-  ;; termination of the program. The meanings of other values is dependent on
-  ;; the environment.
-  (func (export "proc_exit")
-    ;; The exit code returned by the process.
-    (param $rval $exitcode_t)
-  )
-
-  ;; Send a signal to the process of the calling thread.
-  ;; Note: This is similar to `raise` in POSIX.
-  (func (export "proc_raise")
-    ;; The signal condition to trigger.
-    (param $sig $signal_t)
-    (result $error $errno_t)
-  )
-
-  ;; Temporarily yield execution of the calling thread.
-  ;; Note: This is similar to `sched_yield` in POSIX.
-  (func (export "proc_sched_yield")
-    (result $error $errno_t)
-  )
-
-  ;; Write high-quality random data into a buffer.
-  ;; This function blocks when the implementation is unable to immediately
-  ;; provide sufficient high-quality random data.
-  ;; This function may execute slowly, so when large mounts of random data are
-  ;; required, it's advisable to use this function to seed a pseudo-random
-  ;; number generator, rather than to provide the random data directly.
-  (func (export "random_get")
-    ;; The buffer to fill with random data.
-    (param $buf data)
-    (result $error $errno_t)
-  )
-
-  ;; Receive a message from a socket.
-  ;; Note: This is similar to `recv` in POSIX, though it also supports reading
-  ;; the data into multiple buffers in the manner of `readv`.
-  (func (export "sock_recv")
-    (param $self $fd_t)
-    ;; List of scatter/gather vectors to which to store data.
-    (param $ri_data $iovec_t_array)
-    ;; Message flags.
-    (param $ri_flags $riflags_t)
-    (result $error $errno_t)
-    ;; Number of bytes stored in ri_data.
-    (result $ro_datalen $size_t)
-    ;; Message flags.
-    (result $ro_flags $roflags_t)
-  )
-
-  ;; Send a message on a socket.
-  ;; Note: This is similar to `send` in POSIX, though it also supports writing
-  ;; the data from multiple buffers in the manner of `writev`.
-  (func (export "sock_send")
-    (param $self $fd_t)
-    ;; List of scatter/gather vectors to which to retrieve data
-    (param $si_data $ciovec_t_array)
-    ;; Message flags.
-    (param $si_flags $siflags_t)
-    (result $error $errno_t)
-    ;; Number of bytes transmitted.
-    (result $so_datalen $size_t)
-  )
-
-  ;; Shut down socket send and receive channels.
-  ;; Note: This is similar to `shutdown` in POSIX.
-  (func (export "sock_shutdown")
-    (param $self $fd_t)
-    ;; Which channels on the socket to shut down.
-    (param $how $sdflags_t)
-    (result $error $errno_t)
-  )
-)
diff --git a/design/wasi_unstable/wasi_unstable.widl b/design/wasi_unstable/wasi_unstable.widl
new file mode 100644
index 00000000..30633d71
--- /dev/null
+++ b/design/wasi_unstable/wasi_unstable.widl
@@ -0,0 +1,519 @@
+;; The wasi_unstable module type.
+;;
+;; Some content here is derived from [CloudABI](https://github.com/NuxiNL/cloudabi).
+
+(import "typenames.wid")
+
+(module $wasi_unstable
+  ;; Linear memory used by the program.
+  (import "memory" (memory))
+
+  ;; The program entry point.
+  (import "_start" (func))
+
+  ;; Read command-line argument data.
+  ;; The size of the array should match that returned by `wasi_args_sizes_get()`
+  (@interface func (export "args_get")
+    (result $error $errno_t)
+    (result $argv $string_array)
+  )
+  ;; Return command-line argument data sizes.
+  (@interface func (export "args_sizes_get")
+    (result $error $errno_t)
+    ;; The number of arguments.
+    (result $argc $size_t)
+    ;; The size of the argument string data.
+    (result $argv_buf_size $size_t)
+  )
+
+  ;; Read environment variable data.
+  ;; The sizes of the buffers should match that returned by `environ.sizes_get()`.
+  (@interface func (export "environ_get")
+    (result $error $errno_t)
+    (result $argv $string_array)
+  )
+  ;; Return command-line argument data sizes.
+  (@interface func (export "environ_sizes_get")
+    ;; The number of arguments.
+    (result $argc $size_t)
+    ;; The size of the argument string data.
+    (result $argv_buf_size $size_t)
+  )
+
+  ;; Return the resolution of a clock.
+  ;; Implementations are required to provide a non-zero value for supported clocks. For unsupported clocks, return `WASI_EINVAL`
+  ;; Note: This is similar to `clock_getres` in POSIX.
+  (@interface func (export "clock_res_get")
+    (result $error $errno_t)
+    ;; The clock for which to return the resolution.
+    (param $clock_id $clockid_t)
+    ;; The resolution of the clock.
+    (result $resolution $timestamp_t)
+  )
+  ;; Return the time value of a clock.
+  ;; Note: This is similar to `clock_gettime` in POSIX.
+  (@interface func (export "clock_time_get")
+    ;; The clock for which to return the time.
+    (param $clock_id $clockid_t)
+    ;; The maximum lag (exclusive) that the returned time value may have, compared to its actual value.
+    (param $precision $timestamp_t)
+    (result $error $errno_t)
+    ;; The time value of the clock.
+    (result $time $timestamp_t)
+  )
+
+  ;; Provide file advisory information on a file descriptor.
+  ;; Note: This is similar to `posix_fadvise` in POSIX.
+  (@interface func (export "fd_advise")
+    (param $self $fd_t)
+    (param $offset $filesize_t) ;; The offset within the file to which the advisory applies.
+    (param $len $filesize_t) ;; The length of the region to which the advisory applies.
+    (param $advice $advice_t) ;; The advice.
+    (result $error $errno_t)
+  )
+
+  ;; Force the allocation of space in a file.
+  ;; Note: This is similar to `posix_fallocate` in POSIX.
+  (@interface func (export "fd_allocate")
+    (param $self $fd_t)
+    ;; The offset at which to start the allocation.
+    (param $offset $filesize_t)
+    ;; The length of the area that is allocated.
+    (param $len $filesize_t)
+    (result $error $errno_t)
+  )
+
+  ;; Close a file descriptor.
+  ;; Note: This is similar to `close` in POSIX.
+  (@interface func (export "fd_close")
+    (param $self $fd_t)
+    (result $error $errno_t)
+  )
+
+  ;; Synchronize the data of a file to disk.
+  ;; Note: This is similar to `fdatasync` in POSIX.
+  (@interface func (export "fd_datasync")
+    (param $self $fd_t)
+    (result $error $errno_t)
+  )
+
+  ;; Get the attributes of a file descriptor.
+  ;; Note: This returns similar flags to `fsync(fd, F_GETFL)` in POSIX, as well as additional fields.
+  (@interface func (export "fd_fdstat_get")
+    (param $self $fd_t)
+    (result $error $errno_t)
+    ;; The buffer where the file descriptor's attributes are stored.
+    (result $fdstat_t)
+  )
+
+  ;; Adjust the flags associated with a file descriptor.
+  ;; Note: This is similar to `fcntl(fd, F_SETFL, flags)` in POSIX.
+  (@interface func (export "fd_fdstat_set_flags")
+    (param $self $fd_t)
+    ;; The desired values of the file descriptor flags.
+    (param $flags $fdflags)
+    (result $error $errno_t)
+  )
+
+  ;;  Adjust the rights associated with a file descriptor.
+  ;; This can only be used to remove rights, and returns `ENOTCAPABLE` if called in a way that would attempt to add rights
+  (@interface func (export "fd_fdstat_set_rights")
+    (param $self $fd_t)
+    ;; The desired rights of the file descriptor.
+    (param $fs_rights_base $rights_t)
+    (param $fs_rights_inheriting $rights_t)
+    (result $error $errno_t)
+  )
+
+  ;; Return the attributes of an open file.
+  (@interface func (export "fd_filestat_get")
+    (param $self $fd_t)
+    (result $error $errno_t)
+    ;; The buffer where the file's attributes are stored.
+    (result $fs_rights_base $rights_t)
+  )
+
+  ;; Adjust the size of an open file. If this increases the file's size, the extra bytes are filled with zeros.
+  ;; Note: This is similar to `ftruncate` in POSIX.
+  (@interface func (export "fd_filestat_set_size")
+    (param $self $fd_t)
+    ;; The desired file size.
+    (param $st_size $filesize_t)
+    (result $error $errno_t)
+  )
+
+  ;; Adjust the timestamps of an open file or directory.
+  ;; Note: This is similar to `futimens` in POSIX.
+  (@interface func (export "fd_filestat_set_times")
+    (param $self $fd_t)
+    ;; The desired values of the data access timestamp.
+    (param $st_atim $timestamp_t)
+    ;; The desired values of the data modification timestamp.
+    (param $st_mtim $timestamp_t)
+    ;; A bitmask indicating which timestamps to adjust.
+    (param $fst_flags $fstflags_t)
+    (result $error $errno_t)
+  )
+
+  ;; Read from a file descriptor, without using and updating the file descriptor's offset.
+  ;; Note: This is similar to `preadv` in POSIX.
+  (@interface func (export "fd_pread")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors in which to store data.
+    (param $iovs $iovec_t_array)
+    ;; The offset within the file at which to read.
+    (param $offset $filesize_t)
+    (result $error $errno_t)
+    ;; The number of bytes read.
+    (result $nread $size_t)
+  )
+
+  ;; Return a description of the given preopened file descriptor.
+  (@interface func (export "fd_prestat_get")
+    (param $self $fd_t)
+    (result $error $errno_t)
+    ;; The buffer where the description is stored.
+    (result $buf $prestat_t)
+  )
+
+  ;; Return a description of the given preopened file descriptor.
+  (@interface func (export "fd_prestat_dir_name")
+    (param $self $fd_t)
+    ;; A buffer into which to write the preopened directory name.
+    (param $path string)
+    (result $error $errno_t)
+  )
+
+  ;; Write to a file descriptor, without using and updating the file descriptor's offset.
+  ;; Note: This is similar to `pwritev` in POSIX.
+  (@interface func (export "fd_pwrite")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors from which to retrieve data.
+    (param $iovs $iovec_t_array)
+    ;; The offset within the file at which to write.
+    (param $offset $filesize_t)
+    (result $error $errno_t)
+    ;; The number of bytes written.
+    (result $nwritten $size_t)
+  )
+
+  ;; Read from a file descriptor.
+  ;; Note: This is similar to `readv` in POSIX.
+  (@interface func (export "fd_read")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors to which to store data.
+    (param $iovs $iovec_t_array)
+    (result $error $errno_t)
+    ;; The number of bytes read.
+    (result $nread $size_t)
+  )
+
+  ;; Read directory entries from a directory.
+  ;; When successful, the contents of the output buffer consist of a sequence of
+  ;; directory entries. Each directory entry consists of a dirent_t object,
+  ;; followed by dirent_t::d_namlen bytes holding the name of the directory
+  ;; entry.
+  ;;
+  ;; This function fills the output buffer as much as possible, potentially
+  ;; truncating the last directory entry. This allows the caller to grow its
+  ;; read buffer size in case it's too small to fit a single large directory
+  ;; entry, or skip the oversized directory entry.
+  (@interface func (export "fd_readdir")
+    (param $self $fd_t)
+    ;; The buffer where directory entries are stored
+    (param $buf data)
+    ;; The location within the directory to start reading
+    (param $cookie $dircookie_t)
+    (result $error $errno_t)
+    ;; The number of bytes stored in the read buffer. If less than the size of the read buffer, the end of the directory has been reached.
+    (result $bufused $size_t)
+  )
+
+  ;; Atomically replace a file descriptor by renumbering another file descriptor.
+  ;;
+  ;; Due to the strong focus on thread safety, this environment does not provide
+  ;; a mechanism to duplicate or renumber a file descriptor to an arbitrary
+  ;; number, like `dup2()`. This would be prone to race conditions, as an actual
+  ;; file descriptor with the same number could be allocated by a different
+  ;; thread at the same time.
+  ;;
+  ;; This function provides a way to atomically renumber file descriptors, which
+  ;; would disappear if `dup2()` were to be removed entirely.
+  (@interface func (export "fd_renumber")
+    (param $self $fd_t)
+    ;; The file descriptor to overwrite.
+    (param $to $fd_t)
+    (result $error $errno_t)
+  )
+
+  ;; Move the offset of a file descriptor.
+  ;; Note: This is similar to `lseek` in POSIX.
+  (@interface func (export "fd_seek")
+    (param $self $fd_t)
+    ;; The number of bytes to move.
+    (param $offset $filedelta_t)
+    ;; The base from which the offset is relative.
+    (param $whence $whence_t)
+    (result $error $errno_t)
+    ;; The new offset of the file descriptor, relative to the start of the file.
+    (result $newoffset $filesize_t)
+  )
+
+  ;; Synchronize the data and metadata of a file to disk.
+  ;; Note: This is similar to `fsync` in POSIX.
+  (@interface func (export "fd_sync")
+    (param $self $fd_t)
+    (result $error $errno_t)
+  )
+
+  ;; Return the current offset of a file descriptor.
+  ;; Note: This is similar to `lseek(fd, 0, SEEK_CUR)` in POSIX.
+  (@interface func (export "fd_tell")
+    (param $self $fd_t)
+    (result $error $errno_t)
+    ;; The current offset of the file descriptor, relative to the start of the file.
+    (result $offset $filesize_t)
+  )
+
+  ;; Write to a file descriptor.
+  ;; Note: This is similar to `writev` in POSIX.
+  (@interface func (export "fd_write")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors from which to retrieve data.
+    (param $iovs $iovec_t_array)
+    (result $error $errno_t)
+    ;; The number of bytes written.
+    (result $nwritten $size_t)
+  )
+
+  ;; Create a directory.
+  ;; Note: This is similar to `mkdirat` in POSIX.
+  (@interface func (export "path_create_directory")
+    (param $self $fd_t)
+    ;; The path at which to create the directory.
+    (param $path string)
+    (result $error $errno_t)
+  )
+
+  ;; Return the attributes of a file or directory.
+  ;; Note: This is similar to `stat` in POSIX.
+  (@interface func (export "path_filestat_get")
+    (param $self $fd_t)
+    ;; Flags determining the method of how the path is resolved.
+    (param $flags $lookupflags_t)
+    ;; The path of the file or directory to inspect.
+    (param $path string)
+    (result $error $errno_t)
+    ;; The buffer where the file's attributes are stored.
+    (result $buf $filestat_t)
+  )
+
+  ;; Adjust the timestamps of a file or directory.
+  ;; Note: This is similar to `utimensat` in POSIX.
+  (@interface func (export "path_filestat_set_times")
+    (param $self $fd_t)
+    ;; Flags determining the method of how the path is resolved.
+    (param $flags $lookupflags_t)
+    ;; The path of the file or directory to operate on.
+    (param $path string)
+    ;; The desired values of the data access timestamp.
+    (param $st_atim $timestamp_t)
+    ;; The desired values of the data modification timestamp.
+    (param $st_mtim $timestamp_t)
+    ;; A bitmask indicating which timestamps to adjust.
+    (param $fst_flags $fstflags_t)
+    (result $error $errno_t)
+  )
+
+  ;; Create a hard link.
+  ;; Note: This is similar to `linkat` in POSIX.
+  (@interface func (export "path_link")
+    (param $self $fd_t)
+    ;; Flags determining the method of how the path is resolved.
+    (param $old_flags $lookupflags_t)
+    ;; The source path from which to link.
+    (param $old_path string)
+    ;; The working directory at which the resolution of the new path starts.
+    (param $new_fd $path)
+    ;; The destination path at which to create the hard link.
+    (param $new_path string)
+    (result $error $errno_t)
+  )
+
+  ;; Open a file or directory.
+  ;;
+  ;; The returned file descriptor is not guaranteed to be the lowest-numbered
+  ;; file descriptor not currently open; it is randomized to prevent
+  ;; applications from depending on making assumptions about indexes, since this
+  ;; is error-prone in multi-threaded contexts. The returned file descriptor is
+  ;; guaranteed to be less than 2**31.
+  ;;
+  ;; Note: This is similar to `openat` in POSIX.
+  (@interface func (export "path_open")
+    (param $self $fd_t)
+    ;; Flags determining the method of how the path is resolved.
+    (param $dirflags $lookupflags_t)
+    ;; The relative path of the file or directory to open, relative to the
+    ;; `dirfd` directory.
+    (param $path string)
+    ;; The method by which to open the file.
+    (param $o_flags $oflags_t)
+    ;; The initial rights of the newly created file descriptor. The
+    ;; implementation is allowed to return a file descriptor with fewer rights
+    ;; than specified, if and only if those rights do not apply to the type of
+    ;; file being opened.
+    ;;
+    ;; The base rights are rights that will apply to operations using the file
+    ;; descriptor itself, while the inheriting rights are rights that apply to
+    ;; file descriptors derived from it.
+    (param $fs_rights_base $rights_t)
+    (param $fs_rights_inherting $rights_t)
+    (result $error $errno_t)
+    ;; The file descriptor of the file that has been opened.
+    (result $opened_fd $fd_t)
+  )
+
+  ;; Read the contents of a symbolic link.
+  ;; Note: This is similar to `readlinkat` in POSIX.
+  (@interface func (export "path_readlink")
+    (param $self $fd_t)
+    ;; The path of the symbolic link from which to read.
+    (param $path)
+    ;; The buffer to which to write the contents of the symbolic link.
+    (param $buf string)
+    (result $error $errno_t)
+    ;; The number of bytes placed in the buffer.
+    (result $bufused $size_t)
+  )
+
+  ;; Remove a directory.
+  ;; Return `__WASI_ENOTEMPTY` if the directory is not empty.
+  ;; Note: This is similar to `unlinkat(fd, path, AT_REMOVEDIR)` in POSIX.
+  (@interface func (export "path_remove_directory")
+    (param $self $fd_t)
+    ;; The path to a directory to remove.
+    (param $path string)
+    (result $error $errno_t)
+  )
+
+  ;; Rename a file or directory.
+  ;; Note: This is similar to `renameat` in POSIX.
+  (@interface func (export "path_rename")
+    (param $self $fd_t)
+    ;; The source path of the file or directory to rename.
+    (param $old_path string)
+    ;; The working directory at which the resolution of the new path starts.
+    (param $new_fd $fd)
+    ;; The destination path to which to rename the file or directory.
+    (param $new_path string)
+    (result $error $errno_t)
+  )
+
+  ;; Create a symbolic link.
+  ;; Note: This is similar to `symlinkat` in POSIX.
+  (@interface func (export "path_symlink")
+    (param $self $fd_t)
+    ;; The contents of the symbolic link.
+    (param $old_path string)
+    ;; The destination path at which to create the symbolic link.
+    (param $new_path string)
+    (result $error $errno_t)
+  )
+
+
+  ;; Unlink a file.
+  ;; Return `__WASI_EISDIR` if the path refers to a directory.
+  ;; Note: This is similar to `unlinkat(fd, path, 0)` in POSIX.
+  (@interface func (export "path_unlink_file")
+    (param $self $fd_t)
+    ;; The path to a file to unlink.
+    (param $path string)
+    (result $error $errno_t)
+  )
+
+  ;; Concurrently poll for the occurrence of a set of events.
+  (@interface func (export "poll_oneoff")
+    ;; The events to which to subscribe.
+    (param $in $subscription_t)
+    ;; The events that have occurred.
+    (param $out $event_t)
+    ;; Both the number of subscriptions and events.
+    (param $nsubscriptions $size_t)
+    (result $error $errno_t)
+    ;; The number of events stored.
+    (result $nevents $size_t)
+  )
+
+  ;; Terminate the process normally. An exit code of 0 indicates successful
+  ;; termination of the program. The meanings of other values is dependent on
+  ;; the environment.
+  (@interface func (export "proc_exit")
+    ;; The exit code returned by the process.
+    (param $rval $exitcode_t)
+  )
+
+  ;; Send a signal to the process of the calling thread.
+  ;; Note: This is similar to `raise` in POSIX.
+  (@interface func (export "proc_raise")
+    ;; The signal condition to trigger.
+    (param $sig $signal_t)
+    (result $error $errno_t)
+  )
+
+  ;; Temporarily yield execution of the calling thread.
+  ;; Note: This is similar to `sched_yield` in POSIX.
+  (@interface func (export "proc_sched_yield")
+    (result $error $errno_t)
+  )
+
+  ;; Write high-quality random data into a buffer.
+  ;; This function blocks when the implementation is unable to immediately
+  ;; provide sufficient high-quality random data.
+  ;; This function may execute slowly, so when large mounts of random data are
+  ;; required, it's advisable to use this function to seed a pseudo-random
+  ;; number generator, rather than to provide the random data directly.
+  (@interface func (export "random_get")
+    ;; The buffer to fill with random data.
+    (param $buf data)
+    (result $error $errno_t)
+  )
+
+  ;; Receive a message from a socket.
+  ;; Note: This is similar to `recv` in POSIX, though it also supports reading
+  ;; the data into multiple buffers in the manner of `readv`.
+  (@interface func (export "sock_recv")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors to which to store data.
+    (param $ri_data $iovec_t_array)
+    ;; Message flags.
+    (param $ri_flags $riflags_t)
+    (result $error $errno_t)
+    ;; Number of bytes stored in ri_data.
+    (result $ro_datalen $size_t)
+    ;; Message flags.
+    (result $ro_flags $roflags_t)
+  )
+
+  ;; Send a message on a socket.
+  ;; Note: This is similar to `send` in POSIX, though it also supports writing
+  ;; the data from multiple buffers in the manner of `writev`.
+  (@interface func (export "sock_send")
+    (param $self $fd_t)
+    ;; List of scatter/gather vectors to which to retrieve data
+    (param $si_data $ciovec_t_array)
+    ;; Message flags.
+    (param $si_flags $siflags_t)
+    (result $error $errno_t)
+    ;; Number of bytes transmitted.
+    (result $so_datalen $size_t)
+  )
+
+  ;; Shut down socket send and receive channels.
+  ;; Note: This is similar to `shutdown` in POSIX.
+  (@interface func (export "sock_shutdown")
+    (param $self $fd_t)
+    ;; Which channels on the socket to shut down.
+    (param $how $sdflags_t)
+    (result $error $errno_t)
+  )
+)

From 1565100e92636ea86157ade786648716766d456e Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 29 Aug 2019 21:55:06 -0700
Subject: [PATCH 11/26] Rename `import` to `use`, since "import" already means
 something in wasm.

---
 design/wasi_unstable/wasi_unstable.widl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/design/wasi_unstable/wasi_unstable.widl b/design/wasi_unstable/wasi_unstable.widl
index 30633d71..730f1c84 100644
--- a/design/wasi_unstable/wasi_unstable.widl
+++ b/design/wasi_unstable/wasi_unstable.widl
@@ -2,7 +2,7 @@
 ;;
 ;; Some content here is derived from [CloudABI](https://github.com/NuxiNL/cloudabi).
 
-(import "typenames.wid")
+(use "typenames.wid")
 
 (module $wasi_unstable
   ;; Linear memory used by the program.

From 7013711860d0fcb9eeef0c0e1bdc7214cc982509 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Wed, 4 Sep 2019 11:12:04 -0700
Subject: [PATCH 12/26] Remove the `_start` import.

It isn't logically part of the `wasi_unstable` module. It's part of the
platform-level ABI.
---
 design/wasi_unstable/wasi_unstable.widl | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/design/wasi_unstable/wasi_unstable.widl b/design/wasi_unstable/wasi_unstable.widl
index 730f1c84..6ec0e7d6 100644
--- a/design/wasi_unstable/wasi_unstable.widl
+++ b/design/wasi_unstable/wasi_unstable.widl
@@ -5,12 +5,9 @@
 (use "typenames.wid")
 
 (module $wasi_unstable
-  ;; Linear memory used by the program.
+  ;; Linear memory to be accessed by WASI functions that need it.
   (import "memory" (memory))
 
-  ;; The program entry point.
-  (import "_start" (func))
-
   ;; Read command-line argument data.
   ;; The size of the array should match that returned by `wasi_args_sizes_get()`
   (@interface func (export "args_get")

From 2e6ec0e2a1eeede32645943deb670f02fbfca7ec Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Wed, 4 Sep 2019 11:13:56 -0700
Subject: [PATCH 13/26] Rename "$self" paramaters to "$fd" to be more
 descriptive.

We're not currently using a method-oriented API, so instead of saying
"self", say "fd", which is what these parameters are.
---
 design/wasi_unstable/wasi_unstable.widl | 68 ++++++++++++-------------
 1 file changed, 34 insertions(+), 34 deletions(-)

diff --git a/design/wasi_unstable/wasi_unstable.widl b/design/wasi_unstable/wasi_unstable.widl
index 6ec0e7d6..2cb9cfff 100644
--- a/design/wasi_unstable/wasi_unstable.widl
+++ b/design/wasi_unstable/wasi_unstable.widl
@@ -62,7 +62,7 @@
   ;; Provide file advisory information on a file descriptor.
   ;; Note: This is similar to `posix_fadvise` in POSIX.
   (@interface func (export "fd_advise")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     (param $offset $filesize_t) ;; The offset within the file to which the advisory applies.
     (param $len $filesize_t) ;; The length of the region to which the advisory applies.
     (param $advice $advice_t) ;; The advice.
@@ -72,7 +72,7 @@
   ;; Force the allocation of space in a file.
   ;; Note: This is similar to `posix_fallocate` in POSIX.
   (@interface func (export "fd_allocate")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The offset at which to start the allocation.
     (param $offset $filesize_t)
     ;; The length of the area that is allocated.
@@ -83,21 +83,21 @@
   ;; Close a file descriptor.
   ;; Note: This is similar to `close` in POSIX.
   (@interface func (export "fd_close")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     (result $error $errno_t)
   )
 
   ;; Synchronize the data of a file to disk.
   ;; Note: This is similar to `fdatasync` in POSIX.
   (@interface func (export "fd_datasync")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     (result $error $errno_t)
   )
 
   ;; Get the attributes of a file descriptor.
   ;; Note: This returns similar flags to `fsync(fd, F_GETFL)` in POSIX, as well as additional fields.
   (@interface func (export "fd_fdstat_get")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     (result $error $errno_t)
     ;; The buffer where the file descriptor's attributes are stored.
     (result $fdstat_t)
@@ -106,7 +106,7 @@
   ;; Adjust the flags associated with a file descriptor.
   ;; Note: This is similar to `fcntl(fd, F_SETFL, flags)` in POSIX.
   (@interface func (export "fd_fdstat_set_flags")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The desired values of the file descriptor flags.
     (param $flags $fdflags)
     (result $error $errno_t)
@@ -115,7 +115,7 @@
   ;;  Adjust the rights associated with a file descriptor.
   ;; This can only be used to remove rights, and returns `ENOTCAPABLE` if called in a way that would attempt to add rights
   (@interface func (export "fd_fdstat_set_rights")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The desired rights of the file descriptor.
     (param $fs_rights_base $rights_t)
     (param $fs_rights_inheriting $rights_t)
@@ -124,7 +124,7 @@
 
   ;; Return the attributes of an open file.
   (@interface func (export "fd_filestat_get")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     (result $error $errno_t)
     ;; The buffer where the file's attributes are stored.
     (result $fs_rights_base $rights_t)
@@ -133,7 +133,7 @@
   ;; Adjust the size of an open file. If this increases the file's size, the extra bytes are filled with zeros.
   ;; Note: This is similar to `ftruncate` in POSIX.
   (@interface func (export "fd_filestat_set_size")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The desired file size.
     (param $st_size $filesize_t)
     (result $error $errno_t)
@@ -142,7 +142,7 @@
   ;; Adjust the timestamps of an open file or directory.
   ;; Note: This is similar to `futimens` in POSIX.
   (@interface func (export "fd_filestat_set_times")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The desired values of the data access timestamp.
     (param $st_atim $timestamp_t)
     ;; The desired values of the data modification timestamp.
@@ -155,7 +155,7 @@
   ;; Read from a file descriptor, without using and updating the file descriptor's offset.
   ;; Note: This is similar to `preadv` in POSIX.
   (@interface func (export "fd_pread")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; List of scatter/gather vectors in which to store data.
     (param $iovs $iovec_t_array)
     ;; The offset within the file at which to read.
@@ -167,7 +167,7 @@
 
   ;; Return a description of the given preopened file descriptor.
   (@interface func (export "fd_prestat_get")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     (result $error $errno_t)
     ;; The buffer where the description is stored.
     (result $buf $prestat_t)
@@ -175,7 +175,7 @@
 
   ;; Return a description of the given preopened file descriptor.
   (@interface func (export "fd_prestat_dir_name")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; A buffer into which to write the preopened directory name.
     (param $path string)
     (result $error $errno_t)
@@ -184,7 +184,7 @@
   ;; Write to a file descriptor, without using and updating the file descriptor's offset.
   ;; Note: This is similar to `pwritev` in POSIX.
   (@interface func (export "fd_pwrite")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; List of scatter/gather vectors from which to retrieve data.
     (param $iovs $iovec_t_array)
     ;; The offset within the file at which to write.
@@ -197,7 +197,7 @@
   ;; Read from a file descriptor.
   ;; Note: This is similar to `readv` in POSIX.
   (@interface func (export "fd_read")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; List of scatter/gather vectors to which to store data.
     (param $iovs $iovec_t_array)
     (result $error $errno_t)
@@ -216,7 +216,7 @@
   ;; read buffer size in case it's too small to fit a single large directory
   ;; entry, or skip the oversized directory entry.
   (@interface func (export "fd_readdir")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The buffer where directory entries are stored
     (param $buf data)
     ;; The location within the directory to start reading
@@ -237,7 +237,7 @@
   ;; This function provides a way to atomically renumber file descriptors, which
   ;; would disappear if `dup2()` were to be removed entirely.
   (@interface func (export "fd_renumber")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The file descriptor to overwrite.
     (param $to $fd_t)
     (result $error $errno_t)
@@ -246,7 +246,7 @@
   ;; Move the offset of a file descriptor.
   ;; Note: This is similar to `lseek` in POSIX.
   (@interface func (export "fd_seek")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The number of bytes to move.
     (param $offset $filedelta_t)
     ;; The base from which the offset is relative.
@@ -259,14 +259,14 @@
   ;; Synchronize the data and metadata of a file to disk.
   ;; Note: This is similar to `fsync` in POSIX.
   (@interface func (export "fd_sync")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     (result $error $errno_t)
   )
 
   ;; Return the current offset of a file descriptor.
   ;; Note: This is similar to `lseek(fd, 0, SEEK_CUR)` in POSIX.
   (@interface func (export "fd_tell")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     (result $error $errno_t)
     ;; The current offset of the file descriptor, relative to the start of the file.
     (result $offset $filesize_t)
@@ -275,7 +275,7 @@
   ;; Write to a file descriptor.
   ;; Note: This is similar to `writev` in POSIX.
   (@interface func (export "fd_write")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; List of scatter/gather vectors from which to retrieve data.
     (param $iovs $iovec_t_array)
     (result $error $errno_t)
@@ -286,7 +286,7 @@
   ;; Create a directory.
   ;; Note: This is similar to `mkdirat` in POSIX.
   (@interface func (export "path_create_directory")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The path at which to create the directory.
     (param $path string)
     (result $error $errno_t)
@@ -295,7 +295,7 @@
   ;; Return the attributes of a file or directory.
   ;; Note: This is similar to `stat` in POSIX.
   (@interface func (export "path_filestat_get")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; Flags determining the method of how the path is resolved.
     (param $flags $lookupflags_t)
     ;; The path of the file or directory to inspect.
@@ -308,7 +308,7 @@
   ;; Adjust the timestamps of a file or directory.
   ;; Note: This is similar to `utimensat` in POSIX.
   (@interface func (export "path_filestat_set_times")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; Flags determining the method of how the path is resolved.
     (param $flags $lookupflags_t)
     ;; The path of the file or directory to operate on.
@@ -325,7 +325,7 @@
   ;; Create a hard link.
   ;; Note: This is similar to `linkat` in POSIX.
   (@interface func (export "path_link")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; Flags determining the method of how the path is resolved.
     (param $old_flags $lookupflags_t)
     ;; The source path from which to link.
@@ -347,7 +347,7 @@
   ;;
   ;; Note: This is similar to `openat` in POSIX.
   (@interface func (export "path_open")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; Flags determining the method of how the path is resolved.
     (param $dirflags $lookupflags_t)
     ;; The relative path of the file or directory to open, relative to the
@@ -373,7 +373,7 @@
   ;; Read the contents of a symbolic link.
   ;; Note: This is similar to `readlinkat` in POSIX.
   (@interface func (export "path_readlink")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The path of the symbolic link from which to read.
     (param $path)
     ;; The buffer to which to write the contents of the symbolic link.
@@ -387,7 +387,7 @@
   ;; Return `__WASI_ENOTEMPTY` if the directory is not empty.
   ;; Note: This is similar to `unlinkat(fd, path, AT_REMOVEDIR)` in POSIX.
   (@interface func (export "path_remove_directory")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The path to a directory to remove.
     (param $path string)
     (result $error $errno_t)
@@ -396,7 +396,7 @@
   ;; Rename a file or directory.
   ;; Note: This is similar to `renameat` in POSIX.
   (@interface func (export "path_rename")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The source path of the file or directory to rename.
     (param $old_path string)
     ;; The working directory at which the resolution of the new path starts.
@@ -409,7 +409,7 @@
   ;; Create a symbolic link.
   ;; Note: This is similar to `symlinkat` in POSIX.
   (@interface func (export "path_symlink")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The contents of the symbolic link.
     (param $old_path string)
     ;; The destination path at which to create the symbolic link.
@@ -422,7 +422,7 @@
   ;; Return `__WASI_EISDIR` if the path refers to a directory.
   ;; Note: This is similar to `unlinkat(fd, path, 0)` in POSIX.
   (@interface func (export "path_unlink_file")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; The path to a file to unlink.
     (param $path string)
     (result $error $errno_t)
@@ -479,7 +479,7 @@
   ;; Note: This is similar to `recv` in POSIX, though it also supports reading
   ;; the data into multiple buffers in the manner of `readv`.
   (@interface func (export "sock_recv")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; List of scatter/gather vectors to which to store data.
     (param $ri_data $iovec_t_array)
     ;; Message flags.
@@ -495,7 +495,7 @@
   ;; Note: This is similar to `send` in POSIX, though it also supports writing
   ;; the data from multiple buffers in the manner of `writev`.
   (@interface func (export "sock_send")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; List of scatter/gather vectors to which to retrieve data
     (param $si_data $ciovec_t_array)
     ;; Message flags.
@@ -508,7 +508,7 @@
   ;; Shut down socket send and receive channels.
   ;; Note: This is similar to `shutdown` in POSIX.
   (@interface func (export "sock_shutdown")
-    (param $self $fd_t)
+    (param $fd $fd_t)
     ;; Which channels on the socket to shut down.
     (param $how $sdflags_t)
     (result $error $errno_t)

From a75b0517e36de249dd2933baaba2f671cdce2b9d Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Wed, 4 Sep 2019 15:23:56 -0700
Subject: [PATCH 14/26] Give names to union types.

---
 design/wasi_unstable/typenames.widl | 80 ++++++++++++++++-------------
 1 file changed, 44 insertions(+), 36 deletions(-)

diff --git a/design/wasi_unstable/typenames.widl b/design/wasi_unstable/typenames.widl
index df97290e..53b01bde 100644
--- a/design/wasi_unstable/typenames.widl
+++ b/design/wasi_unstable/typenames.widl
@@ -488,17 +488,21 @@
     (field $error $errno_t)
     ;; The type of the event that occurred.
     (field $type $eventtype_t)
-    (field $u
-      (union
-        ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
-        (field $fd_readwrite
-          (struct
-            ;; The number of bytes available for reading or writing.
-            (field $nbytes $filesize_t)
-            ;; The state of the file descriptor.
-            (field $flags $eventrwflags_t)
-          )
-        )
+    ;; The contents of the event.
+    (field $u $event_u))
+  )
+)
+
+;; The contents of an $event_t.
+(typename $event_u
+  (union
+    ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
+    (field $fd_readwrite
+      (struct
+        ;; The number of bytes available for reading or writing.
+        (field $nbytes $filesize_t)
+        ;; The state of the file descriptor.
+        (field $flags $eventrwflags_t)
       )
     )
   )
@@ -549,31 +553,35 @@
     (field $userdata $userdata_t)
     ;; The type of the event to which to subscribe.
     (field $type $eventtype_t)
-    (field $u
-      (union
-        ;; When type is `__WASI_EVENTTYPE_CLOCK`:
-        (field $clock
-          (struct
-            ;; The user-defined unique identifier of the clock.
-            (field $identifier $userdata_t)
-            ;; The clock against which to compare the timestamp.
-            (field $clock_id $clockid_t)
-            ;; The absolute or relative timestamp.
-            (field $timeout $timestamp_t)
-            ;; The amount of time that the implementation may wait additionally
-            ;; to coalesce with other events.
-            ;;
-            ;; Flags specifying whether the timeout is absolute or relative
-            (field $precision $timestamp_t)
-          )
-        )
-        ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
-        (field $fd_readwrite
-          (struct
-            ;; The file descriptor on which to wait for it to become ready for reading or writing.
-            (field $file_descriptor $fd_t)
-          )
-        )
+    ;; The contents of the subscription.
+    (field $u $subscription_u)
+  )
+)
+
+;; The contents of a $subscription_t.
+(typename $subscription_u
+  (union
+    ;; When type is `__WASI_EVENTTYPE_CLOCK`:
+    (field $clock
+      (struct
+        ;; The user-defined unique identifier of the clock.
+        (field $identifier $userdata_t)
+        ;; The clock against which to compare the timestamp.
+        (field $clock_id $clockid_t)
+        ;; The absolute or relative timestamp.
+        (field $timeout $timestamp_t)
+        ;; The amount of time that the implementation may wait additionally
+        ;; to coalesce with other events.
+        ;;
+        ;; Flags specifying whether the timeout is absolute or relative
+        (field $precision $timestamp_t)
+      )
+    )
+    ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
+    (field $fd_readwrite
+      (struct
+        ;; The file descriptor on which to wait for it to become ready for reading or writing.
+        (field $file_descriptor $fd_t)
       )
     )
   )

From 7b07f0f1307a44958eb2c8057405f736ee7ec19c Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Wed, 4 Sep 2019 15:33:18 -0700
Subject: [PATCH 15/26] Give names to struct types.

---
 design/wasi_unstable/typenames.widl | 69 +++++++++++++++++------------
 1 file changed, 40 insertions(+), 29 deletions(-)

diff --git a/design/wasi_unstable/typenames.widl b/design/wasi_unstable/typenames.widl
index 53b01bde..90aac966 100644
--- a/design/wasi_unstable/typenames.widl
+++ b/design/wasi_unstable/typenames.widl
@@ -497,14 +497,18 @@
 (typename $event_u
   (union
     ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
-    (field $fd_readwrite
-      (struct
-        ;; The number of bytes available for reading or writing.
-        (field $nbytes $filesize_t)
-        ;; The state of the file descriptor.
-        (field $flags $eventrwflags_t)
-      )
-    )
+    (field $fd_readwrite $event_fd_readwrite_t)
+  )
+)
+
+;; The contents of an $event_t when type is `__WASI_EVENTTYPE_FD_READ` or
+;; `__WASI_EVENTTYPE_FD_WRITE`.
+(typename $event_fd_readwrite_t
+  (struct
+    ;; The number of bytes available for reading or writing.
+    (field $nbytes $filesize_t)
+    ;; The state of the file descriptor.
+    (field $flags $eventrwflags_t)
   )
 )
 
@@ -562,28 +566,35 @@
 (typename $subscription_u
   (union
     ;; When type is `__WASI_EVENTTYPE_CLOCK`:
-    (field $clock
-      (struct
-        ;; The user-defined unique identifier of the clock.
-        (field $identifier $userdata_t)
-        ;; The clock against which to compare the timestamp.
-        (field $clock_id $clockid_t)
-        ;; The absolute or relative timestamp.
-        (field $timeout $timestamp_t)
-        ;; The amount of time that the implementation may wait additionally
-        ;; to coalesce with other events.
-        ;;
-        ;; Flags specifying whether the timeout is absolute or relative
-        (field $precision $timestamp_t)
-      )
-    )
+    (field $clock $subscription_clock_t)
     ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
-    (field $fd_readwrite
-      (struct
-        ;; The file descriptor on which to wait for it to become ready for reading or writing.
-        (field $file_descriptor $fd_t)
-      )
-    )
+    (field $fd_readwrite $subscription_fd_readwrite_t)
+  )
+)
+
+;; The contents of a $subscription_t when type is `__WASI_EVENTTYPE_CLOCK`.
+(typename $subscription_clock_t
+  (struct
+    ;; The user-defined unique identifier of the clock.
+    (field $identifier $userdata_t)
+    ;; The clock against which to compare the timestamp.
+    (field $clock_id $clockid_t)
+    ;; The absolute or relative timestamp.
+    (field $timeout $timestamp_t)
+    ;; The amount of time that the implementation may wait additionally
+    ;; to coalesce with other events.
+    ;;
+    ;; Flags specifying whether the timeout is absolute or relative
+    (field $precision $timestamp_t)
+  )
+)
+
+;; The contents of a $subscription_t when type is type is
+;; `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`.
+(typename $subscription_fd_readwrite_t
+  (struct
+    ;; The file descriptor on which to wait for it to become ready for reading or writing.
+    (field $file_descriptor $fd_t)
   )
 )
 

From a9702286b4895199a23edb5efc4cd6b09daaf3a5 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Wed, 4 Sep 2019 16:55:50 -0700
Subject: [PATCH 16/26] Rename .widl to .witx.

---
 design/wasi_unstable/{typenames.widl => typenames.witx}         | 0
 design/wasi_unstable/{wasi_unstable.widl => wasi_unstable.witx} | 0
 2 files changed, 0 insertions(+), 0 deletions(-)
 rename design/wasi_unstable/{typenames.widl => typenames.witx} (100%)
 rename design/wasi_unstable/{wasi_unstable.widl => wasi_unstable.witx} (100%)

diff --git a/design/wasi_unstable/typenames.widl b/design/wasi_unstable/typenames.witx
similarity index 100%
rename from design/wasi_unstable/typenames.widl
rename to design/wasi_unstable/typenames.witx
diff --git a/design/wasi_unstable/wasi_unstable.widl b/design/wasi_unstable/wasi_unstable.witx
similarity index 100%
rename from design/wasi_unstable/wasi_unstable.widl
rename to design/wasi_unstable/wasi_unstable.witx

From dfd5883ec63581dd5fd2e232a131fc86cef45b43 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Wed, 4 Sep 2019 17:10:34 -0700
Subject: [PATCH 17/26] Fix extra close paren.

---
 design/wasi_unstable/typenames.witx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/design/wasi_unstable/typenames.witx b/design/wasi_unstable/typenames.witx
index 90aac966..06df2177 100644
--- a/design/wasi_unstable/typenames.witx
+++ b/design/wasi_unstable/typenames.witx
@@ -489,7 +489,7 @@
     ;; The type of the event that occurred.
     (field $type $eventtype_t)
     ;; The contents of the event.
-    (field $u $event_u))
+    (field $u $event_u)
   )
 )
 

From a2931a0cb3c78940ab561406b375033fa708d342 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 5 Sep 2019 08:57:45 -0700
Subject: [PATCH 18/26] Use ciovec_t for fd_write and fd_pwrite.

---
 design/wasi_unstable/wasi_unstable.witx | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/design/wasi_unstable/wasi_unstable.witx b/design/wasi_unstable/wasi_unstable.witx
index 2cb9cfff..54ea0765 100644
--- a/design/wasi_unstable/wasi_unstable.witx
+++ b/design/wasi_unstable/wasi_unstable.witx
@@ -186,7 +186,7 @@
   (@interface func (export "fd_pwrite")
     (param $fd $fd_t)
     ;; List of scatter/gather vectors from which to retrieve data.
-    (param $iovs $iovec_t_array)
+    (param $iovs $ciovec_t_array)
     ;; The offset within the file at which to write.
     (param $offset $filesize_t)
     (result $error $errno_t)
@@ -277,7 +277,7 @@
   (@interface func (export "fd_write")
     (param $fd $fd_t)
     ;; List of scatter/gather vectors from which to retrieve data.
-    (param $iovs $iovec_t_array)
+    (param $iovs $ciovec_t_array)
     (result $error $errno_t)
     ;; The number of bytes written.
     (result $nwritten $size_t)

From bb6d142990a52d94decadf4a4d9a8a5056baa3b4 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 5 Sep 2019 09:00:32 -0700
Subject: [PATCH 19/26] Don't use interface types to pass mutable buffers.

This adds new constructs, (@witx pointer T), and (@witx const_pointer T),
and uses them to describe raw pointers to linear memory buffers. For
now, these can be treated essentially the same as $uintptr_t, though in
the future we may do something more sophisticated.
---
 design/wasi_unstable/typenames.witx     |  6 ++----
 design/wasi_unstable/wasi_unstable.witx | 22 ++++++++++++++--------
 2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/design/wasi_unstable/typenames.witx b/design/wasi_unstable/typenames.witx
index 06df2177..87ee29d6 100644
--- a/design/wasi_unstable/typenames.witx
+++ b/design/wasi_unstable/typenames.witx
@@ -3,8 +3,6 @@
 ;; Some content here is derived from [CloudABI](https://github.com/NuxiNL/cloudabi).
 
 (typename $size_t u32)
-(typename $uintptr_t u32)
-(typename $string_array (array string))
 
 ;; Non-negative file size or length of a region within a file.
 (typename $filesize_t u64)
@@ -283,7 +281,7 @@
 (typename $iovec_t
   (struct
     ;; The address and length of the buffer to be filled.
-    (field $buf $uintptr_t)
+    (field $buf (@witx pointer u8))
     (field $buf_len $size_t)
   )
 )
@@ -292,7 +290,7 @@
 (typename $ciovec_t
   (struct
     ;; The address and length of the buffer to be written.
-    (field $buf $uintptr_t)
+    (field $buf (@witx const_pointer u8))
     (field $buf_len $size_t)
   )
 )
diff --git a/design/wasi_unstable/wasi_unstable.witx b/design/wasi_unstable/wasi_unstable.witx
index 54ea0765..23f8931e 100644
--- a/design/wasi_unstable/wasi_unstable.witx
+++ b/design/wasi_unstable/wasi_unstable.witx
@@ -11,8 +11,9 @@
   ;; Read command-line argument data.
   ;; The size of the array should match that returned by `wasi_args_sizes_get()`
   (@interface func (export "args_get")
+    (param $argv (@witx pointer (@witx pointer u8)))
+    (param $argv_buf (@witx pointer u8))
     (result $error $errno_t)
-    (result $argv $string_array)
   )
   ;; Return command-line argument data sizes.
   (@interface func (export "args_sizes_get")
@@ -26,8 +27,9 @@
   ;; Read environment variable data.
   ;; The sizes of the buffers should match that returned by `environ.sizes_get()`.
   (@interface func (export "environ_get")
+    (param $environ (@witx pointer (@witx pointer u8)))
+    (param $environ_buf (@witx pointer u8))
     (result $error $errno_t)
-    (result $argv $string_array)
   )
   ;; Return command-line argument data sizes.
   (@interface func (export "environ_sizes_get")
@@ -177,7 +179,8 @@
   (@interface func (export "fd_prestat_dir_name")
     (param $fd $fd_t)
     ;; A buffer into which to write the preopened directory name.
-    (param $path string)
+    (param $path (@witx pointer u8))
+    (param $path_len $size_t)
     (result $error $errno_t)
   )
 
@@ -218,7 +221,8 @@
   (@interface func (export "fd_readdir")
     (param $fd $fd_t)
     ;; The buffer where directory entries are stored
-    (param $buf data)
+    (param $buf (@witx pointer u8))
+    (param $buf_len $size_t)
     ;; The location within the directory to start reading
     (param $cookie $dircookie_t)
     (result $error $errno_t)
@@ -377,7 +381,8 @@
     ;; The path of the symbolic link from which to read.
     (param $path)
     ;; The buffer to which to write the contents of the symbolic link.
-    (param $buf string)
+    (param $buf (@witx pointer u8))
+    (param $buf_len $size_t)
     (result $error $errno_t)
     ;; The number of bytes placed in the buffer.
     (result $bufused $size_t)
@@ -431,9 +436,9 @@
   ;; Concurrently poll for the occurrence of a set of events.
   (@interface func (export "poll_oneoff")
     ;; The events to which to subscribe.
-    (param $in $subscription_t)
+    (param $in (const_pointer $subscription_t))
     ;; The events that have occurred.
-    (param $out $event_t)
+    (param $out (@witx pointer $event_t))
     ;; Both the number of subscriptions and events.
     (param $nsubscriptions $size_t)
     (result $error $errno_t)
@@ -471,7 +476,8 @@
   ;; number generator, rather than to provide the random data directly.
   (@interface func (export "random_get")
     ;; The buffer to fill with random data.
-    (param $buf data)
+    (param $buf (@witx pointer u8))
+    (param $buf_len $size_t)
     (result $error $errno_t)
   )
 

From fc69216acfc8a6dfae202d8e10c34befd448c788 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 5 Sep 2019 09:21:13 -0700
Subject: [PATCH 20/26] Fix a missing @witx.

---
 design/wasi_unstable/wasi_unstable.witx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/design/wasi_unstable/wasi_unstable.witx b/design/wasi_unstable/wasi_unstable.witx
index 23f8931e..82b75ef2 100644
--- a/design/wasi_unstable/wasi_unstable.witx
+++ b/design/wasi_unstable/wasi_unstable.witx
@@ -436,7 +436,7 @@
   ;; Concurrently poll for the occurrence of a set of events.
   (@interface func (export "poll_oneoff")
     ;; The events to which to subscribe.
-    (param $in (const_pointer $subscription_t))
+    (param $in (@witx const_pointer $subscription_t))
     ;; The events that have occurred.
     (param $out (@witx pointer $event_t))
     ;; Both the number of subscriptions and events.

From 2ec3a17030edb7b7418c74586aa96556f81391ae Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 5 Sep 2019 09:46:18 -0700
Subject: [PATCH 21/26] Give each field its own comment, instead of commenting
 them as a group.

---
 design/wasi_unstable/typenames.witx | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/design/wasi_unstable/typenames.witx b/design/wasi_unstable/typenames.witx
index 87ee29d6..021c750a 100644
--- a/design/wasi_unstable/typenames.witx
+++ b/design/wasi_unstable/typenames.witx
@@ -280,8 +280,9 @@
 ;; A region of memory for scatter/gather reads.
 (typename $iovec_t
   (struct
-    ;; The address and length of the buffer to be filled.
+    ;; The address of the buffer to be filled.
     (field $buf (@witx pointer u8))
+    ;; The length of the buffer to be filled.
     (field $buf_len $size_t)
   )
 )
@@ -289,8 +290,9 @@
 ;; A region of memory for scatter/gather writes.
 (typename $ciovec_t
   (struct
-    ;; The address and length of the buffer to be written.
+    ;; The address of the buffer to be written.
     (field $buf (@witx const_pointer u8))
+    ;; The length of the buffer to be written.
     (field $buf_len $size_t)
   )
 )

From fe65a69ade7e2cb581257b930891eb306b2861e2 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Thu, 5 Sep 2019 12:25:59 -0700
Subject: [PATCH 22/26] Add a document on `witx`.

---
 design/wasi_unstable/typenames.witx     |  3 +++
 design/wasi_unstable/wasi_unstable.witx |  3 +++
 docs/witx.md                            | 30 +++++++++++++++++++++++++
 3 files changed, 36 insertions(+)
 create mode 100644 docs/witx.md

diff --git a/design/wasi_unstable/typenames.witx b/design/wasi_unstable/typenames.witx
index 021c750a..14fd81e4 100644
--- a/design/wasi_unstable/typenames.witx
+++ b/design/wasi_unstable/typenames.witx
@@ -1,6 +1,9 @@
 ;; Type names used by the wasi_unstable module type.
 ;;
 ;; Some content here is derived from [CloudABI](https://github.com/NuxiNL/cloudabi).
+;;
+;; This is a `witx` file. See [here](https://github.com/WebAssembly/WASI/tree/master/docs/witx.md)
+;; for an explanation of what that means.
 
 (typename $size_t u32)
 
diff --git a/design/wasi_unstable/wasi_unstable.witx b/design/wasi_unstable/wasi_unstable.witx
index 82b75ef2..c47541b9 100644
--- a/design/wasi_unstable/wasi_unstable.witx
+++ b/design/wasi_unstable/wasi_unstable.witx
@@ -1,6 +1,9 @@
 ;; The wasi_unstable module type.
 ;;
 ;; Some content here is derived from [CloudABI](https://github.com/NuxiNL/cloudabi).
+;;
+;; This is a `witx` file. See [here](https://github.com/WebAssembly/WASI/tree/master/docs/witx.md)
+;; for an explanation of what that means.
 
 (use "typenames.wid")
 
diff --git a/docs/witx.md b/docs/witx.md
new file mode 100644
index 00000000..db267992
--- /dev/null
+++ b/docs/witx.md
@@ -0,0 +1,30 @@
+# Know your `witx`
+
+The `witx` file format is an experimental format which is based on the
+[module types] text format (`wit`), (which is in turn based on the
+[wat format], which is based on [S-expressions]). It adds some features
+using the same syntax as [interface types], some features with syntax
+similar to [gc types], as well as a few special features of its own.
+
+`witx` is actively evolving. Expect backwards-incompatible changes,
+particularly in the areas where `witx` differs from `wit`.
+
+The initial goal for `witx` is just to have a language suitable for
+expressing [WASI] APIs in, to serve as the vocabulary for proposing changes
+to existing APIs and proposing new APIs. Initially, while it uses some of
+the syntax and concepts from interface types, it doesn't currently imply the
+full interface types specification, or the use of the interface types custom
+sections.
+
+We expect that eventually we will transition to using the full interface
+types specification. Until then, the goals here are to remain aligned with
+interface types and other relevant WebAssembly standards and proposals
+wherever practical, and to be an input into the design process of interface
+types.
+
+[module types]: https://github.com/WebAssembly/module-types/blob/master/proposals/module-types/Overview.md
+[interface types]: https://github.com/WebAssembly/interface-types/blob/master/proposals/interface-types/Explainer.md
+[gc types]: https://github.com/WebAssembly/gc
+[wat format]: https://webassembly.github.io/spec/core/bikeshed/index.html#text-format%E2%91%A0
+[S-expressions]: https://en.wikipedia.org/wiki/S-expression
+[WASI]: https://github.com/WebAssembly/WASI

From df8e670290e6aa84565ad581f11485f90d64498b Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Mon, 9 Sep 2019 10:22:56 -0700
Subject: [PATCH 23/26] Add $prestat_t and friends.

---
 design/wasi_unstable/typenames.witx | 34 +++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/design/wasi_unstable/typenames.witx b/design/wasi_unstable/typenames.witx
index 14fd81e4..226ec4e7 100644
--- a/design/wasi_unstable/typenames.witx
+++ b/design/wasi_unstable/typenames.witx
@@ -719,3 +719,37 @@
     (flag $SHUT_WR)
   )
 )
+
+;; Information about a pre-opened capability.
+(typename $prestat_t
+  (struct
+    ;; The type of the pre-opened capability.
+    (field $pr_type $preopentype_t)
+    ;; The contents of the information.
+    (field $u $prestat_u)
+  )
+)
+
+;; Identifiers for preopened capabilities.
+(typename preopentype_t
+  (enum u8
+    ;; A pre-opened directory.
+    $PREOPENTYPE_DIR
+  )
+)
+
+;; The contents of an $prestat_t.
+(typename $prestat_u
+  (union
+    ;; When type is `PREOPENTYPE_DIR`:
+    (field $dir $prestat_dir)
+  )
+)
+
+;; The contents of a $prestat_t when type is `PREOPENTYPE_DIR`.
+(typename $prestat_dir
+  (struct
+    ;; The length of the directory name for use with `fd_prestat_dir_name`.
+    (field $pr_name_len $size_t)
+  )
+)

From 6497e90b45c8967944b72dbffd6ae07034d22b59 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Mon, 9 Sep 2019 10:28:25 -0700
Subject: [PATCH 24/26] Remove `__wasi_` and `__WASI_` prefixes from names in
 comments.

---
 design/wasi_unstable/typenames.witx     | 141 ++++++++++++------------
 design/wasi_unstable/wasi_unstable.witx |   4 +-
 2 files changed, 71 insertions(+), 74 deletions(-)

diff --git a/design/wasi_unstable/typenames.witx b/design/wasi_unstable/typenames.witx
index 226ec4e7..4bab3073 100644
--- a/design/wasi_unstable/typenames.witx
+++ b/design/wasi_unstable/typenames.witx
@@ -197,79 +197,78 @@
 ;; File descriptor rights, determining which actions may be performed.
 (typename $rights_t
   (flags u64
-    ;; The right to invoke `__wasi_fd_datasync()`.
+    ;; The right to invoke `fd_datasync`.
     ;;
-    ;; If `__WASI_RIGHT_PATH_OPEN` is set, includes the right to invoke
-    ;; `__wasi_path_open()` with `__WASI_FDFLAG_DSYNC`.
+    ;; If `RIGHT_PATH_OPEN` is set, includes the right to invoke
+    ;; `path_open` with `FDFLAG_DSYNC`.
     (flag $RIGHT_FD_DATASYNC)
-    ;; The right to invoke `__wasi_fd_read()` and `__wasi_sock_recv()`.
+    ;; The right to invoke `fd_read` and `sock_recv`.
     ;;
-    ;; If `__WASI_RIGHT_FD_SEEK` is set, includes the right to invoke
-    ;; `__wasi_fd_pread()`.
+    ;; If `RIGHT_FD_SEEK` is set, includes the right to invoke `fd_pread`.
     (flag $RIGHT_FD_READ)
-    ;; The right to invoke `__wasi_fd_seek()`. This flag implies `__WASI_RIGHT_FD_TELL`.
+    ;; The right to invoke `fd_seek`. This flag implies `RIGHT_FD_TELL`.
     (flag $RIGHT_FD_SEEK)
-    ;; The right to invoke `__wasi_fd_fdstat_set_flags()`.
+    ;; The right to invoke `fd_fdstat_set_flags`.
     (flag $RIGHT_FD_FDSTAT_SET_FLAGS)
-    ;; The right to invoke `__wasi_fd_sync()`.
+    ;; The right to invoke `fd_sync`.
     ;;
-    ;; If `__WASI_RIGHT_PATH_OPEN` is set, includes the right to invoke
-    ;; `__wasi_path_open()` with `__WASI_FDFLAG_RSYNC` and `__WASI_FDFLAG_DSYNC`.
+    ;; If `RIGHT_PATH_OPEN` is set, includes the right to invoke
+    ;; `path_open` with `FDFLAG_RSYNC` and `FDFLAG_DSYNC`.
     (flag $RIGHT_FD_SYNC)
-    ;; The right to invoke `__wasi_fd_seek()` in such a way that the file offset
-    ;; remains unaltered (i.e., `__WASI_WHENCE_CUR` with offset zero), or to
-    ;; invoke `__wasi_fd_tell()`.
+    ;; The right to invoke `fd_seek` in such a way that the file offset
+    ;; remains unaltered (i.e., `WHENCE_CUR` with offset zero), or to
+    ;; invoke `fd_tell`.
     (flag $RIGHT_FD_TELL)
-    ;; The right to invoke `__wasi_fd_write()` and `__wasi_sock_send()`.
-    ;; If `__WASI_RIGHT_FD_SEEK` is set, includes the right to invoke `__wasi_fd_pwrite()`.
+    ;; The right to invoke `fd_write` and `sock_send`.
+    ;; If `RIGHT_FD_SEEK` is set, includes the right to invoke `fd_pwrite`.
     (flag $RIGHT_FD_WRITE)
-    ;; The right to invoke `__wasi_fd_advise()`.
+    ;; The right to invoke `fd_advise`.
     (flag $RIGHT_FD_ADVISE)
-    ;; The right to invoke `__wasi_fd_allocate()`.
+    ;; The right to invoke `fd_allocate`.
     (flag $RIGHT_FD_ALLOCATE)
-    ;; The right to invoke `__wasi_path_create_directory()`.
+    ;; The right to invoke `path_create_directory`.
     (flag $RIGHT_PATH_CREATE_DIRECTORY)
-    ;; If `__WASI_RIGHT_PATH_OPEN` is set, the right to invoke `__wasi_path_open()` with `__WASI_O_CREAT`.
+    ;; If `RIGHT_PATH_OPEN` is set, the right to invoke `path_open` with `O_CREAT`.
     (flag $RIGHT_PATH_CREATE_FILE)
-    ;; The right to invoke `__wasi_path_link()` with the file descriptor as the
+    ;; The right to invoke `path_link` with the file descriptor as the
     ;; source directory.
     (flag $RIGHT_PATH_LINK_SOURCE)
-    ;; The right to invoke `__wasi_path_link()` with the file descriptor as the
+    ;; The right to invoke `path_link` with the file descriptor as the
     ;; target directory.
     (flag $RIGHT_PATH_LINK_TARGET)
-    ;; The right to invoke `__wasi_path_open()`.
+    ;; The right to invoke `path_open`.
     (flag $RIGHT_PATH_OPEN)
-    ;; The right to invoke `__wasi_fd_readdir()`.
+    ;; The right to invoke `fd_readdir`.
     (flag $RIGHT_FD_READDIR)
-    ;; The right to invoke `__wasi_path_readlink()`.
+    ;; The right to invoke `path_readlink`.
     (flag $RIGHT_PATH_READLINK)
-    ;; The right to invoke `__wasi_path_rename()` with the file descriptor as the source directory.
+    ;; The right to invoke `path_rename` with the file descriptor as the source directory.
     (flag $RIGHT_PATH_RENAME_SOURCE)
-    ;; The right to invoke `__wasi_path_rename()` with the file descriptor as the target directory.
+    ;; The right to invoke `path_rename` with the file descriptor as the target directory.
     (flag $RIGHT_PATH_RENAME_TARGET)
-    ;; The right to invoke `__wasi_path_filestat_get()`.
+    ;; The right to invoke `path_filestat_get`.
     (flag $RIGHT_PATH_FILESTAT_GET)
-    ;; The right to change a file's size (there is no `__wasi_path_filestat_set_size()`).
-    ;; If `__WASI_RIGHT_PATH_OPEN` is set, includes the right to invoke `__wasi_path_open()` with `__WASI_O_TRUNC`.
+    ;; The right to change a file's size (there is no `path_filestat_set_size`).
+    ;; If `RIGHT_PATH_OPEN` is set, includes the right to invoke `path_open` with `O_TRUNC`.
     (flag $RIGHT_PATH_FILESTAT_SET_SIZE)
-    ;; The right to invoke `__wasi_path_filestat_set_times()`.
+    ;; The right to invoke `path_filestat_set_times`.
     (flag $RIGHT_PATH_FILESTAT_SET_TIMES)
-    ;; The right to invoke `__wasi_fd_filestat_get()`.
+    ;; The right to invoke `fd_filestat_get`.
     (flag $RIGHT_FD_FILESTAT_GET)
-    ;; The right to invoke `__wasi_fd_filestat_set_size()`.
+    ;; The right to invoke `fd_filestat_set_size`.
     (flag $RIGHT_FD_FILESTAT_SET_SIZE)
-    ;; The right to invoke `__wasi_fd_filestat_set_times()`.
+    ;; The right to invoke `fd_filestat_set_times`.
     (flag $RIGHT_FD_FILESTAT_SET_TIMES)
-    ;; The right to invoke `__wasi_path_symlink()`.
+    ;; The right to invoke `path_symlink`.
     (flag $RIGHT_PATH_SYMLINK)
-    ;; The right to invoke `__wasi_path_unlink_file()`.
+    ;; The right to invoke `path_unlink_file`.
     (flag $RIGHT_PATH_UNLINK_FILE)
-    ;; The right to invoke `__wasi_path_remove_directory()`.
+    ;; The right to invoke `path_remove_directory`.
     (flag $RIGHT_PATH_REMOVE_DIRECTORY)
-    ;; If `__WASI_RIGHT_FD_READ` is set, includes the right to invoke `__wasi_poll_oneoff()` to subscribe to `__WASI_EVENTTYPE_FD_READ`.
-    ;; If `__WASI_RIGHT_FD_WRITE` is set, includes the right to invoke `__wasi_poll_oneoff()` to subscribe to `__WASI_EVENTTYPE_FD_WRITE`.
+    ;; If `RIGHT_FD_READ` is set, includes the right to invoke `poll_oneoff` to subscribe to `EVENTTYPE_FD_READ`.
+    ;; If `RIGHT_FD_WRITE` is set, includes the right to invoke `poll_oneoff` to subscribe to `EVENTTYPE_FD_WRITE`.
     (flag $RIGHT_POLL_FD_READWRITE)
-    ;; The right to invoke `__wasi_sock_shutdown()`.
+    ;; The right to invoke `sock_shutdown`.
     (flag $RIGHT_SOCK_SHUTDOWN)
   )
 )
@@ -381,15 +380,13 @@
     ;; Rights that apply to this file descriptor.
     (field $fs_rights_base $rights_t)
     ;; Maximum set of rights that may be installed on new file descriptors that
-    ;; are created through this file descriptor, e.g., through
-    ;; `__wasi_path_open()`.
+    ;; are created through this file descriptor, e.g., through `path_open`.
     (field $fs_rights_inheriting $rights_t)
   )
 )
 
 ;; Identifier for a device containing a file system. Can be used in combination
-;; with __wasi_inode_t to uniquely identify a file or directory in the
-;; filesystem.
+;; with `inode_t` to uniquely identify a file or directory in the filesystem.
 (typename $device_t u64)
 
 ;; The type of a file descriptor or file.
@@ -417,13 +414,13 @@
 ;; Which file time attributes to adjust.
 (typename $fstflags_t
   (flags u16
-    ;; Adjust the last data access timestamp to the value stored in __wasi_filestat_t::st_atim.
+    ;; Adjust the last data access timestamp to the value stored in `filestat_t::st_atim`.
     (flag $FILESTAT_SET_ATIM)
-    ;; Adjust the last data access timestamp to the time of clock `__WASI_CLOCK_REALTIME`.
+    ;; Adjust the last data access timestamp to the time of clock `CLOCK_REALTIME`.
     (flag $FILESTAT_SET_ATIM_NOW)
-    ;; Adjust the last data modification timestamp to the value stored in __wasi_filestat_t::st_mtim.
+    ;; Adjust the last data modification timestamp to the value stored in `filestat_t::st_mtim`.
     (flag $FILESTAT_SET_MTIM)
-    ;; Adjust the last data modification timestamp to the time of clock `__WASI_CLOCK_REALTIME`.
+    ;; Adjust the last data modification timestamp to the time of clock `CLOCK_REALTIME`.
     (flag $FILESTAT_SET_MTIM_NOW)
   )
 )
@@ -439,7 +436,7 @@
   )
 )
 
-;; Open flags used by `__wasi_path_open()`.
+;; Open flags used by `path_open`.
 (typename $oflags_t
   (flags u16
     ;; Create file if it does not exist.
@@ -485,7 +482,7 @@
 ;; An event that occurred.
 (typename $event_t
   (struct
-    ;; User-provided value that got attached to __wasi_subscription_t::userdata.
+    ;; User-provided value that got attached to `subscription_t::userdata`.
     (field $userdata $userdata_t)
     ;; If non-zero, an error that occurred while processing the subscription request.
     (field $error $errno_t)
@@ -499,13 +496,13 @@
 ;; The contents of an $event_t.
 (typename $event_u
   (union
-    ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
+    ;; When type is `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`:
     (field $fd_readwrite $event_fd_readwrite_t)
   )
 )
 
-;; The contents of an $event_t when type is `__WASI_EVENTTYPE_FD_READ` or
-;; `__WASI_EVENTTYPE_FD_WRITE`.
+;; The contents of an $event_t when type is `EVENTTYPE_FD_READ` or
+;; `EVENTTYPE_FD_WRITE`.
 (typename $event_fd_readwrite_t
   (struct
     ;; The number of bytes available for reading or writing.
@@ -516,7 +513,7 @@
 )
 
 ;; The state of the file descriptor subscribed to with
-;; `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`.
+;; `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`.
 (typename $eventrwflags_t
   (flags u16
     ;; The peer of this socket has closed or disconnected.
@@ -527,27 +524,27 @@
 ;; Type of a subscription to an event or its occurrence.
 (typename $eventtype_t
   (flags u8
-    ;; The time value of clock __wasi_subscription_t::u.clock.clock_id has
-    ;; reached timestamp __wasi_subscription_t::u.clock.timeout.
+    ;; The time value of clock `subscription_t::u.clock.clock_id` has
+    ;; reached timestamp `subscription_t::u.clock.timeout`.
     (flag $EVENTTYPE_CLOCK)
-    ;; File descriptor __wasi_subscription_t::u.fd_readwrite.fd has data
+    ;; File descriptor `subscription_t::u.fd_readwrite.fd` has data
     ;; available for reading. This event always triggers for regular files.
     (flag $EVENTTYPE_FD_READ)
-    ;; File descriptor __wasi_subscription_t::u.fd_readwrite.fd has capacity
+    ;; File descriptor `subscription_t::u.fd_readwrite.fd` has capacity
     ;; available for writing. This event always triggers for regular files.
     (flag $EVENTTYPE_FD_WRITE)
   )
 )
 
 ;; Flags determining how to interpret the timestamp provided in
-;; __wasi_subscription_t::u.clock.timeout.
+;; `subscription_t::u.clock.timeout.`
 (typename $subclockflags_t
   (flags u16
     ;; If set, treat the timestamp provided in
-    ;; __wasi_subscription_t::u.clock.timeout as an absolute timestamp of clock
-    ;; __wasi_subscription_t::u.clock.clock_id. If clear, treat the timestamp
-    ;; provided in __wasi_subscription_t::u.clock.timeout relative to the
-    ;; current time value of clock __wasi_subscription_t::u.clock.clock_id.
+    ;; `subscription_t::u.clock.timeout` as an absolute timestamp of clock
+    ;; `subscription_t::u.clock.clock_id.` If clear, treat the timestamp
+    ;; provided in `subscription_t::u.clock.timeout` relative to the
+    ;; current time value of clock `subscription_t::u.clock.clock_id.`
     (flag $SUBSCRIPTION_CLOCK_ABSTIME)
   )
 )
@@ -556,7 +553,7 @@
 (typename $subscription_t
   (struct
     ;; User-provided value that is attached to the subscription in the
-    ;; implementation and returned through __wasi_event_t::userdata.
+    ;; implementation and returned through `event_t::userdata`.
     (field $userdata $userdata_t)
     ;; The type of the event to which to subscribe.
     (field $type $eventtype_t)
@@ -568,14 +565,14 @@
 ;; The contents of a $subscription_t.
 (typename $subscription_u
   (union
-    ;; When type is `__WASI_EVENTTYPE_CLOCK`:
+    ;; When type is `EVENTTYPE_CLOCK`:
     (field $clock $subscription_clock_t)
-    ;; When type is `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`:
+    ;; When type is `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`:
     (field $fd_readwrite $subscription_fd_readwrite_t)
   )
 )
 
-;; The contents of a $subscription_t when type is `__WASI_EVENTTYPE_CLOCK`.
+;; The contents of a $subscription_t when type is `EVENTTYPE_CLOCK`.
 (typename $subscription_clock_t
   (struct
     ;; The user-defined unique identifier of the clock.
@@ -593,7 +590,7 @@
 )
 
 ;; The contents of a $subscription_t when type is type is
-;; `__WASI_EVENTTYPE_FD_READ` or `__WASI_EVENTTYPE_FD_WRITE`.
+;; `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`.
 (typename $subscription_fd_readwrite_t
   (struct
     ;; The file descriptor on which to wait for it to become ready for reading or writing.
@@ -688,7 +685,7 @@
   )
 )
 
-;; Flags provided to `__wasi_sock_recv()`.
+;; Flags provided to `sock_recv`.
 (typename $riflags_t
   (flags u16
     ;; Returns the message without removing it from the socket's receive queue.
@@ -698,15 +695,15 @@
   )
 )
 
-;; Flags returned by `__wasi_sock_recv()`.
+;; Flags returned by `sock_recv`.
 (typename $roflags_t
   (flags u16
-    ;; Returned by `__wasi_sock_recv()`: Message data has been truncated.
+    ;; Returned by `sock_recv`: Message data has been truncated.
     (flag $SOCK_RECV_DATA_TRUNCATED)
   )
 )
 
-;; Flags provided to `__wasi_sock_send()`. As there are currently no flags
+;; Flags provided to `sock_send`. As there are currently no flags
 ;; defined, it must be set to zero.
 (typename $siflags_t u16)
 
diff --git a/design/wasi_unstable/wasi_unstable.witx b/design/wasi_unstable/wasi_unstable.witx
index c47541b9..4a48cc38 100644
--- a/design/wasi_unstable/wasi_unstable.witx
+++ b/design/wasi_unstable/wasi_unstable.witx
@@ -392,7 +392,7 @@
   )
 
   ;; Remove a directory.
-  ;; Return `__WASI_ENOTEMPTY` if the directory is not empty.
+  ;; Return `ENOTEMPTY` if the directory is not empty.
   ;; Note: This is similar to `unlinkat(fd, path, AT_REMOVEDIR)` in POSIX.
   (@interface func (export "path_remove_directory")
     (param $fd $fd_t)
@@ -427,7 +427,7 @@
 
 
   ;; Unlink a file.
-  ;; Return `__WASI_EISDIR` if the path refers to a directory.
+  ;; Return `EISDIR` if the path refers to a directory.
   ;; Note: This is similar to `unlinkat(fd, path, 0)` in POSIX.
   (@interface func (export "path_unlink_file")
     (param $fd $fd_t)

From 1ce9ef4ef24d5bfb6b7ff308c97733e9c0d1ac0d Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Tue, 10 Sep 2019 15:12:48 -0700
Subject: [PATCH 25/26] Pick up some validation fixes from lucet-idl.

See https://github.com/fastly/lucet/pull/275/files#diff-1ac8557cf1c286d69d13ccaa4b21d291
---
 design/wasi_unstable/wasi_unstable.witx | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/design/wasi_unstable/wasi_unstable.witx b/design/wasi_unstable/wasi_unstable.witx
index 4a48cc38..6d4bea54 100644
--- a/design/wasi_unstable/wasi_unstable.witx
+++ b/design/wasi_unstable/wasi_unstable.witx
@@ -5,7 +5,7 @@
 ;; This is a `witx` file. See [here](https://github.com/WebAssembly/WASI/tree/master/docs/witx.md)
 ;; for an explanation of what that means.
 
-(use "typenames.wid")
+(use "typenames.witx")
 
 (module $wasi_unstable
   ;; Linear memory to be accessed by WASI functions that need it.
@@ -105,7 +105,7 @@
     (param $fd $fd_t)
     (result $error $errno_t)
     ;; The buffer where the file descriptor's attributes are stored.
-    (result $fdstat_t)
+    (result $stat $fdstat_t)
   )
 
   ;; Adjust the flags associated with a file descriptor.
@@ -113,7 +113,7 @@
   (@interface func (export "fd_fdstat_set_flags")
     (param $fd $fd_t)
     ;; The desired values of the file descriptor flags.
-    (param $flags $fdflags)
+    (param $flags $fdflags_t)
     (result $error $errno_t)
   )
 
@@ -332,13 +332,13 @@
   ;; Create a hard link.
   ;; Note: This is similar to `linkat` in POSIX.
   (@interface func (export "path_link")
-    (param $fd $fd_t)
+    (param $old_fd $fd_t)
     ;; Flags determining the method of how the path is resolved.
     (param $old_flags $lookupflags_t)
     ;; The source path from which to link.
     (param $old_path string)
     ;; The working directory at which the resolution of the new path starts.
-    (param $new_fd $path)
+    (param $new_fd $fd_t)
     ;; The destination path at which to create the hard link.
     (param $new_path string)
     (result $error $errno_t)
@@ -382,7 +382,7 @@
   (@interface func (export "path_readlink")
     (param $fd $fd_t)
     ;; The path of the symbolic link from which to read.
-    (param $path)
+    (param $path string)
     ;; The buffer to which to write the contents of the symbolic link.
     (param $buf (@witx pointer u8))
     (param $buf_len $size_t)
@@ -408,7 +408,7 @@
     ;; The source path of the file or directory to rename.
     (param $old_path string)
     ;; The working directory at which the resolution of the new path starts.
-    (param $new_fd $fd)
+    (param $new_fd $fd_t)
     ;; The destination path to which to rename the file or directory.
     (param $new_path string)
     (result $error $errno_t)

From 2cf06aa10130b1fd54804730f29c9c59c378d372 Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Tue, 10 Sep 2019 15:24:32 -0700
Subject: [PATCH 26/26] Reorder typenames so that definitions precede uses.

The wat format allows forward references to '$' identifiers, so we'll
probably have to support this eventually too, but for now, reorder
things to make it easy to process.
---
 design/wasi_unstable/typenames.witx | 202 ++++++++++++++--------------
 1 file changed, 101 insertions(+), 101 deletions(-)

diff --git a/design/wasi_unstable/typenames.witx b/design/wasi_unstable/typenames.witx
index 4bab3073..1d33a35f 100644
--- a/design/wasi_unstable/typenames.witx
+++ b/design/wasi_unstable/typenames.witx
@@ -276,9 +276,6 @@
 ;; A file descriptor index.
 (typename $fd_t u32)
 
-(typename $iovec_t_array (array $iovec_t))
-(typename $ciovec_t_array (array $ciovec_t))
-
 ;; A region of memory for scatter/gather reads.
 (typename $iovec_t
   (struct
@@ -299,6 +296,9 @@
   )
 )
 
+(typename $iovec_t_array (array $iovec_t))
+(typename $ciovec_t_array (array $ciovec_t))
+
 ;; Relative offset within a file.
 (typename $filedelta_t s64)
 
@@ -317,9 +317,34 @@
 ;; A reference to the offset of a directory entry.
 (typename $dircookie_t u64)
 
-;; The type for the $d_namelen field of $dirent_t.
+;; The type for the $d_namlen field of $dirent_t.
 (typename $dirnamlen_t u32)
 
+;; File serial number that is unique within its file system.
+(typename $inode_t u64)
+
+;; The type of a file descriptor or file.
+(typename $filetype_t
+  (enum u8
+    ;; The type of the file descriptor or file is unknown or is different from any of the other types specified.
+    $FILETYPE_UNKNOWN
+    ;; The file descriptor or file refers to a block device inode.
+    $FILETYPE_BLOCK_DEVICE
+    ;; The file descriptor or file refers to a character device inode.
+    $FILETYPE_CHARACTER_DEVICE
+    ;; The file descriptor or file refers to a directory inode.
+    $FILETYPE_DIRECTORY
+    ;; The file descriptor or file refers to a regular file inode.
+    $FILETYPE_REGULAR_FILE
+    ;; The file descriptor or file refers to a datagram socket.
+    $FILETYPE_SOCKET_DGRAM
+    ;; The file descriptor or file refers to a byte-stream socket.
+    $FILETYPE_SOCKET_STREAM
+    ;; The file refers to a symbolic link inode.
+    $FILETYPE_SYMBOLIC_LINK
+  )
+)
+
 ;; A directory entry.
 (typename $dirent_t
   (struct
@@ -328,7 +353,7 @@
     ;; The serial number of the file referred to by this directory entry.
     (field $d_ino $inode_t)
     ;; The length of the name of the directory entry.
-    (field $d_namlen $dirnamelen_t)
+    (field $d_namlen $dirnamlen_t)
     ;; The type of the file referred to by this directory entry.
     (field $d_type $filetype_t)
   )
@@ -389,28 +414,6 @@
 ;; with `inode_t` to uniquely identify a file or directory in the filesystem.
 (typename $device_t u64)
 
-;; The type of a file descriptor or file.
-(typename $filetype_t
-  (enum u8
-    ;; The type of the file descriptor or file is unknown or is different from any of the other types specified.
-    $FILETYPE_UNKNOWN
-    ;; The file descriptor or file refers to a block device inode.
-    $FILETYPE_BLOCK_DEVICE
-    ;; The file descriptor or file refers to a character device inode.
-    $FILETYPE_CHARACTER_DEVICE
-    ;; The file descriptor or file refers to a directory inode.
-    $FILETYPE_DIRECTORY
-    ;; The file descriptor or file refers to a regular file inode.
-    $FILETYPE_REGULAR_FILE
-    ;; The file descriptor or file refers to a datagram socket.
-    $FILETYPE_SOCKET_DGRAM
-    ;; The file descriptor or file refers to a byte-stream socket.
-    $FILETYPE_SOCKET_STREAM
-    ;; The file refers to a symbolic link inode.
-    $FILETYPE_SYMBOLIC_LINK
-  )
-)
-
 ;; Which file time attributes to adjust.
 (typename $fstflags_t
   (flags u16
@@ -425,9 +428,6 @@
   )
 )
 
-;; File serial number that is unique within its file system.
-(typename $inode_t u64)
-
 ;; Flags determining the method of how paths are resolved.
 (typename $lookupflags_t
   (flags u32
@@ -479,25 +479,27 @@
 ;; extracted from the implementation.
 (typename $userdata_t u64)
 
-;; An event that occurred.
-(typename $event_t
-  (struct
-    ;; User-provided value that got attached to `subscription_t::userdata`.
-    (field $userdata $userdata_t)
-    ;; If non-zero, an error that occurred while processing the subscription request.
-    (field $error $errno_t)
-    ;; The type of the event that occurred.
-    (field $type $eventtype_t)
-    ;; The contents of the event.
-    (field $u $event_u)
+;; Type of a subscription to an event or its occurrence.
+(typename $eventtype_t
+  (flags u8
+    ;; The time value of clock `subscription_t::u.clock.clock_id` has
+    ;; reached timestamp `subscription_t::u.clock.timeout`.
+    (flag $EVENTTYPE_CLOCK)
+    ;; File descriptor `subscription_t::u.fd_readwrite.fd` has data
+    ;; available for reading. This event always triggers for regular files.
+    (flag $EVENTTYPE_FD_READ)
+    ;; File descriptor `subscription_t::u.fd_readwrite.fd` has capacity
+    ;; available for writing. This event always triggers for regular files.
+    (flag $EVENTTYPE_FD_WRITE)
   )
 )
 
-;; The contents of an $event_t.
-(typename $event_u
-  (union
-    ;; When type is `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`:
-    (field $fd_readwrite $event_fd_readwrite_t)
+;; The state of the file descriptor subscribed to with
+;; `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`.
+(typename $eventrwflags_t
+  (flags u16
+    ;; The peer of this socket has closed or disconnected.
+    (flag $EVENT_FD_READWRITE_HANGUP)
   )
 )
 
@@ -512,27 +514,25 @@
   )
 )
 
-;; The state of the file descriptor subscribed to with
-;; `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`.
-(typename $eventrwflags_t
-  (flags u16
-    ;; The peer of this socket has closed or disconnected.
-    (flag $EVENT_FD_READWRITE_HANGUP)
+;; The contents of an $event_t.
+(typename $event_u
+  (union
+    ;; When type is `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`:
+    (field $fd_readwrite $event_fd_readwrite_t)
   )
 )
 
-;; Type of a subscription to an event or its occurrence.
-(typename $eventtype_t
-  (flags u8
-    ;; The time value of clock `subscription_t::u.clock.clock_id` has
-    ;; reached timestamp `subscription_t::u.clock.timeout`.
-    (flag $EVENTTYPE_CLOCK)
-    ;; File descriptor `subscription_t::u.fd_readwrite.fd` has data
-    ;; available for reading. This event always triggers for regular files.
-    (flag $EVENTTYPE_FD_READ)
-    ;; File descriptor `subscription_t::u.fd_readwrite.fd` has capacity
-    ;; available for writing. This event always triggers for regular files.
-    (flag $EVENTTYPE_FD_WRITE)
+;; An event that occurred.
+(typename $event_t
+  (struct
+    ;; User-provided value that got attached to `subscription_t::userdata`.
+    (field $userdata $userdata_t)
+    ;; If non-zero, an error that occurred while processing the subscription request.
+    (field $error $errno_t)
+    ;; The type of the event that occurred.
+    (field $type $eventtype_t)
+    ;; The contents of the event.
+    (field $u $event_u)
   )
 )
 
@@ -549,29 +549,6 @@
   )
 )
 
-;; Subscription to an event.
-(typename $subscription_t
-  (struct
-    ;; User-provided value that is attached to the subscription in the
-    ;; implementation and returned through `event_t::userdata`.
-    (field $userdata $userdata_t)
-    ;; The type of the event to which to subscribe.
-    (field $type $eventtype_t)
-    ;; The contents of the subscription.
-    (field $u $subscription_u)
-  )
-)
-
-;; The contents of a $subscription_t.
-(typename $subscription_u
-  (union
-    ;; When type is `EVENTTYPE_CLOCK`:
-    (field $clock $subscription_clock_t)
-    ;; When type is `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`:
-    (field $fd_readwrite $subscription_fd_readwrite_t)
-  )
-)
-
 ;; The contents of a $subscription_t when type is `EVENTTYPE_CLOCK`.
 (typename $subscription_clock_t
   (struct
@@ -598,6 +575,29 @@
   )
 )
 
+;; The contents of a $subscription_t.
+(typename $subscription_u
+  (union
+    ;; When type is `EVENTTYPE_CLOCK`:
+    (field $clock $subscription_clock_t)
+    ;; When type is `EVENTTYPE_FD_READ` or `EVENTTYPE_FD_WRITE`:
+    (field $fd_readwrite $subscription_fd_readwrite_t)
+  )
+)
+
+;; Subscription to an event.
+(typename $subscription_t
+  (struct
+    ;; User-provided value that is attached to the subscription in the
+    ;; implementation and returned through `event_t::userdata`.
+    (field $userdata $userdata_t)
+    ;; The type of the event to which to subscribe.
+    (field $type $eventtype_t)
+    ;; The contents of the subscription.
+    (field $u $subscription_u)
+  )
+)
+
 ;; Exit code generated by a process when exiting.
 (typename $exitcode_t u32)
 
@@ -717,16 +717,6 @@
   )
 )
 
-;; Information about a pre-opened capability.
-(typename $prestat_t
-  (struct
-    ;; The type of the pre-opened capability.
-    (field $pr_type $preopentype_t)
-    ;; The contents of the information.
-    (field $u $prestat_u)
-  )
-)
-
 ;; Identifiers for preopened capabilities.
 (typename preopentype_t
   (enum u8
@@ -735,6 +725,14 @@
   )
 )
 
+;; The contents of a $prestat_t when type is `PREOPENTYPE_DIR`.
+(typename $prestat_dir
+  (struct
+    ;; The length of the directory name for use with `fd_prestat_dir_name`.
+    (field $pr_name_len $size_t)
+  )
+)
+
 ;; The contents of an $prestat_t.
 (typename $prestat_u
   (union
@@ -743,10 +741,12 @@
   )
 )
 
-;; The contents of a $prestat_t when type is `PREOPENTYPE_DIR`.
-(typename $prestat_dir
+;; Information about a pre-opened capability.
+(typename $prestat_t
   (struct
-    ;; The length of the directory name for use with `fd_prestat_dir_name`.
-    (field $pr_name_len $size_t)
+    ;; The type of the pre-opened capability.
+    (field $pr_type $preopentype_t)
+    ;; The contents of the information.
+    (field $u $prestat_u)
   )
 )