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bug#61095: [PATCH 2/3] Remove racy optimized file descriptor closing loo
From: |
Ludovic Courtès |
Subject: |
bug#61095: [PATCH 2/3] Remove racy optimized file descriptor closing loop in 'spawn'. |
Date: |
Thu, 30 Mar 2023 00:30:56 +0200 |
This reverts 9332b632407894c2e1951cce1bc678f19e1fa8e4, thereby
reinstating the performance issue in <https://bugs.gnu.org/59321>.
This optimization was subject to race conditions in multi-threaded code:
new file descriptors could pop up at any time and thus leak in the
child.
* libguile/posix.c (close_inherited_fds): Remove.
(close_inherited_fds_slow): Rename to...
(close_inherited_fds): ... this.
---
libguile/posix.c | 30 +-----------------------------
1 file changed, 1 insertion(+), 29 deletions(-)
diff --git a/libguile/posix.c b/libguile/posix.c
index 68e9bfade..b5830c43b 100644
--- a/libguile/posix.c
+++ b/libguile/posix.c
@@ -1323,7 +1323,7 @@ SCM_DEFINE (scm_fork, "primitive-fork", 0, 0, 0,
#endif /* HAVE_FORK */
static void
-close_inherited_fds_slow (posix_spawn_file_actions_t *actions, int max_fd)
+close_inherited_fds (posix_spawn_file_actions_t *actions, int max_fd)
{
while (--max_fd > 2)
{
@@ -1346,34 +1346,6 @@ close_inherited_fds_slow (posix_spawn_file_actions_t
*actions, int max_fd)
}
}
-static void
-close_inherited_fds (posix_spawn_file_actions_t *actions, int max_fd)
-{
- DIR *dirp;
- struct dirent *d;
- int fd;
-
- /* Try to use the platform-specific list of open file descriptors, so
- we don't need to use the brute force approach. */
- dirp = opendir ("/proc/self/fd");
-
- if (dirp == NULL)
- return close_inherited_fds_slow (actions, max_fd);
-
- while ((d = readdir (dirp)) != NULL)
- {
- fd = atoi (d->d_name);
-
- /* Skip "." and "..", garbage entries, stdin/stdout/stderr. */
- if (fd <= 2)
- continue;
-
- posix_spawn_file_actions_addclose (actions, fd);
- }
-
- closedir (dirp);
-}
-
static pid_t
do_spawn (char *exec_file, char **exec_argv, char **exec_env,
int in, int out, int err, int spawnp)
--
2.39.2