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record: Find the execution binary in PATH #741

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May 13, 2019
Merged

record: Find the execution binary in PATH #741

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65 changes: 51 additions & 14 deletions cmds/record.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1467,10 +1467,7 @@ static void print_child_usage(struct rusage *ru)
ru->ru_utime.tv_sec, ru->ru_utime.tv_usec);
}

#define UFTRACE_MSG "Cannot trace '%s': No such executable file\n" \
"\tNote that uftrace doesn't search $PATH for you.\n" \
"\tIf you really want to trace executables in the $PATH,\n" \
"\tplease give it the absolute pathname (like /usr/bin/%s).\n"
#define UFTRACE_MSG "Cannot trace '%s': No such executable file.\n"

#define MCOUNT_MSG "Can't find '%s' symbol in the '%s'.\n" \
"\tIt seems not to be compiled with -pg or -finstrument-functions flag\n" \
Expand All @@ -1497,6 +1494,49 @@ static void print_child_usage(struct rusage *ru)
# define EM_AARCH64 183
#endif

static bool is_regular_executable(const char *pathname)
{
struct stat sb;

if (!stat(pathname, &sb)) {
if (S_ISREG(sb.st_mode) && (sb.st_mode & S_IXUSR))
return true;
}
return false;
}

static void find_in_path(char **exename)
{
/* try to find the binary in PATH */
struct strv strv = STRV_INIT;
char *env = getenv("PATH");
char *pathname = NULL;
char *path;
bool found = false;
int i;

if (!env || *exename[0] == '/')
pr_err_ns(UFTRACE_MSG, *exename);

/* search opts->exename in PATH one by one */
strv_split(&strv, env, ":");

strv_for_each(&strv, path, i) {
xasprintf(&pathname, "%s/%s", path, *exename);
if (is_regular_executable(pathname)) {
found = true;
break;
}
free(pathname);
}

if (!found)
pr_err_ns(UFTRACE_MSG, *exename);

*exename = pathname;
strv_free(&strv);
}

static void check_binary(struct opts *opts)
{
int fd;
Expand All @@ -1510,14 +1550,11 @@ static void check_binary(struct opts *opts)
};

again:
pr_dbg3("checking binary %s\n", opts->exename);
/* if it cannot be found in PATH, then fails inside */
if (!is_regular_executable(opts->exename))
find_in_path(&opts->exename);

if (access(opts->exename, X_OK) < 0) {
if (errno == ENOENT && opts->exename[0] != '/') {
pr_err_ns(UFTRACE_MSG, opts->exename, opts->exename);
}
pr_err("Cannot trace '%s'", opts->exename);
}
pr_dbg("checking binary %s\n", opts->exename);

fd = open(opts->exename, O_RDONLY);
if (fd < 0)
Expand All @@ -1533,7 +1570,7 @@ static void check_binary(struct opts *opts)
if (script == NULL)
pr_err_ns(UFTRACE_ELF_MSG, opts->exename);

if (!opts->force)
if (!opts->force && !opts->patch)
pr_err_ns(SCRIPT_MSG, opts->exename);

/* ignore options */
Expand Down Expand Up @@ -2052,8 +2089,8 @@ int do_child_exec(int ready, struct opts *opts,
pr_err("waiting for parent failed");

/*
* I don't think the traced binary is in PATH.
* So use plain 'execv' rather than 'execvp'.
* The traced binary is already resolved into absolute pathname.
* So plain 'execv' is enough and no need to use 'execvp'.
*/
execv(opts->exename, argv);
abort();
Expand Down