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Fix leak reported by Valgrind when setting environment variables

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The call to setenv replaces the string in the environ array, which causes
the original string to be reported as a memory leak.

This commit allocates another copy of environ called alloc_environ that
contains the strings allocated by ruby_init_setproctitle. Then in
ruby_free_proctitle it frees all the strings in alloc_environ.

For example:

    ENV.each { |k, v| ENV[k] = v.dup }

Valgrind reports:

    3,321 bytes in 39 blocks are definitely lost in loss record 3 of 3
      at 0x484884F: malloc (vg_replace_malloc.c:393)
      by 0x25CB5B: objspace_xmalloc0 (gc.c:11972)
      by 0x40344E: ruby_strdup (util.c:540)
      by 0x59C854: ruby_init_setproctitle (setproctitle.c:143)
      by 0x38CC44: ruby_process_options (ruby.c:3101)
      by 0x234DB1: ruby_options (eval.c:117)
      by 0x15B92E: rb_main (main.c:40)
      by 0x15B92E: main (main.c:59)
This commit is contained in:
Peter Zhu 2024-04-30 17:22:04 -04:00
parent 57eca0a80d
commit d1f14bafb0
1 changed files with 13 additions and 12 deletions
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25
missing/setproctitle.c
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@ -88,6 +88,7 @@ static char **argv1_addr = NULL;
#if ALLOCATE_ENVIRON
static char **orig_environ = NULL;
static char **alloc_environ = NULL;
#endif
void
@ -112,7 +113,10 @@ compat_init_setproctitle(int argc, char *argv[])
/* Fail if we can't allocate room for the new environment */
for (i = 0; envp[i] != NULL; i++);
orig_environ = environ = xcalloc(i + 1, sizeof(*environ));
orig_environ = environ;
alloc_environ = xcalloc(i + 1, sizeof(*environ));
environ = xcalloc(i + 1, sizeof(*environ));
if (environ == NULL) {
environ = envp; /* put it back */
return;
@ -140,8 +144,8 @@ compat_init_setproctitle(int argc, char *argv[])
argv_env_len = lastenvp - argv[0];
for (i = 0; envp[i] != NULL; i++)
environ[i] = ruby_strdup(envp[i]);
environ[i] = NULL;
alloc_environ[i] = environ[i] = ruby_strdup(envp[i]);
alloc_environ[i] = environ[i] = NULL;
#endif /* SPT_REUSEARGV */
}
@ -153,16 +157,13 @@ ruby_free_proctitle(void)
if (!orig_environ) return; /* environ is allocated by OS */
/* ruby_setenv could allocate a new environ, so we need to free orig_environ
* in that case. */
if (environ != orig_environ) {
for (int i = 0; orig_environ[i] != NULL; i++) {
xfree(orig_environ[i]);
}
xfree(orig_environ);
orig_environ = NULL;
for (int i = 0; alloc_environ[i] != NULL; i++) {
xfree(alloc_environ[i]);
}
xfree(alloc_environ);
xfree(environ);
environ = orig_environ;
#endif
}