convert to getopt_long for option parsing

[namhyung]

Currently it uses argp_parse() to parse command line options. But it's glibc-specific so has some portability problems. While there's a supporting library for this, it'd be nice to avoid using it. I think it's rather straight-forward to convert the option parser to use getopt_long() instead.

[honggyukim]

This is one of the most valuable work items as a first step to support Android.

[binkoni]

I want to contribute this issue!

[honggyukim]

I want to contribute this issue!

Great! Please go ahead.

[namhyung]

@binkoni can I take this over?

[binkoni]

@namhyung Sure you can :) 2020년 3월 29일 (일) 오후 4:37, Namhyung Kim <[email protected]>님이 작성:

…

@binkoni <https://github.com/binkoni> can I take this over? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#871 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQNFIHOTNZU53INMPTNULDRJ33ERANCNFSM4IW2O5OQ> .

[namhyung]

Pushed review/getopt-v1.

[honggyukim]

Thanks a lot for the update. It mostly works fine, but it doesn't properly pass target options.

$ uftrace record -P. ./chrome --no-sandbox --headless https://www.google.com
uftrace: unrecognized option '--no-sandbox'
uftrace: /home/honggyu/work/uftrace/cmds/record.c:1542:find_in_path
 ERROR: Cannot trace '--headless': No such executable file.

It requires explicit -- mark as follows.

$ uftrace record -P. -- ./chrome --no-sandbox --headless https://www.google.com

[honggyukim]

The simpler example is as follows.

$ gcc -pg -o t-abc tests/s-abc.c

$ ./t-abc
$ uftrace ./t-abc
# DURATION     TID     FUNCTION
   1.459 us [ 19883] | __monstartup();
   1.019 us [ 19883] | __cxa_atexit();
            [ 19883] | main() {
            [ 19883] |   a() {
            [ 19883] |     b() {
            [ 19883] |       c() {
   0.815 us [ 19883] |         getpid();
   2.005 us [ 19883] |       } /* c */
   2.578 us [ 19883] |     } /* b */
   3.002 us [ 19883] |   } /* a */
   3.473 us [ 19883] | } /* main */

The following --target-option is expected to be used as an option for t-abc itself instead of uftrace option, but it doesn't work.

$ ./t-abc --target-option
$ uftrace ./t-abc --target-option
uftrace: unrecognized option '--target-option'
uftrace -- function (graph) tracer for userspace

Usage: uftrace [COMMAND] [OPTION...] [<program>]

 COMMAND: record|replay|live|report|graph|info|dump|recv|script|tui

[namhyung]

Thanks for testing. I don't know how I can control that..

[namhyung]

Oh, I found that we can control non-option behavior using the short option string prefix ("+"). Please check review/getopt-v2.

from the man page of getopt_long(3):

By default, getopt() permutes the contents of argv as it scans, so that eventually all the nonoptions are at the end. Two other modes are also implemented. If the first character of optstring is '+' or the environment variable POSIXLY_CORRECT is set, then option processing stops as soon as a nonoption argument is encountered. If the first character of optstring is '-', then each nonoption argv-element is handled as if it were the argument of an option with character code 1. (This is used by programs that were written to expect options and other argv-elements in any order and that care about the ordering of the two.) The special argument "--" forces an end of option-scanning regardless of the scanning mode.

[honggyukim]

I tested and confirmed that it works fine now. Thanks a lot for your work!

[namhyung]

Thanks for the testing!