From: "Ludovic Courtès" <ludo@gnu.org>
To: 61095@debbugs.gnu.org
Cc: "Ludovic Courtès" <ludo@gnu.org>,
"Josselin Poiret" <dev@jpoiret.xyz>,
"Omar Polo" <op@omarpolo.com>,
"Andrew Whatson" <whatson@tailcall.au>
Subject: bug#61095: [PATCH 1/3] 'spawn' closes only open file descriptors on non-GNU/Linux systems.
Date: Thu, 30 Mar 2023 00:30:55 +0200 [thread overview]
Message-ID: <20230329223057.28100-1-ludo@gnu.org> (raw)
In-Reply-To: <87zg7vjimr.fsf@inria.fr>
Fixes <https://bugs.gnu.org/61095>.
Reported by Omar Polo <op@omarpolo.com>.
* libguile/posix.c (close_inherited_fds_slow): On systems other than
GNU/Linux, call 'addclose' only when 'fcntl' succeeds on MAX_FD.
---
libguile/posix.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/libguile/posix.c b/libguile/posix.c
index 3a8be94e4..68e9bfade 100644
--- a/libguile/posix.c
+++ b/libguile/posix.c
@@ -1326,7 +1326,24 @@ static void
close_inherited_fds_slow (posix_spawn_file_actions_t *actions, int max_fd)
{
while (--max_fd > 2)
- posix_spawn_file_actions_addclose (actions, max_fd);
+ {
+ /* Adding a 'close' action for a file descriptor that is not open
+ causes 'posix_spawn' to fail on GNU/Hurd and on OpenBSD, but
+ not on GNU/Linux: <https://bugs.gnu.org/61095>. Hence this
+ strategy:
+
+ - On GNU/Linux, close every FD, since that's the only
+ race-free way to make sure the child doesn't inherit one.
+ - On other systems, only close FDs currently open in the
+ parent; it works, but it's racy (XXX).
+
+ The only reliable option is 'addclosefrom'. */
+#if ! (defined __GLIBC__ && defined __linux__)
+ int flags = fcntl (max_fd, F_GETFD, NULL);
+ if (flags >= 0)
+#endif
+ posix_spawn_file_actions_addclose (actions, max_fd);
+ }
}
static void
base-commit: e334e59589c3cbfc68d3f7d0d739000e0876b36d
--
2.39.2
next prev parent reply other threads:[~2023-03-29 22:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-27 11:51 bug#61095: possible misuse of posix_spawn API on non-linux OSes Omar Polo
2023-01-27 12:25 ` Omar Polo
2023-03-28 9:34 ` Ludovic Courtès
2023-03-28 16:10 ` Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2023-03-29 22:30 ` Ludovic Courtès
2023-03-29 22:30 ` Ludovic Courtès [this message]
2023-03-29 22:30 ` bug#61095: [PATCH 2/3] Remove racy optimized file descriptor closing loop in 'spawn' Ludovic Courtès
2023-03-29 22:30 ` bug#61095: [PATCH 3/3] Use 'posix_spawn_file_actions_addclosefrom_np' where available Ludovic Courtès
2023-03-30 20:21 ` bug#61095: possible misuse of posix_spawn API on non-linux OSes Josselin Poiret via Bug reports for GUILE, GNU's Ubiquitous Extension Language
2023-03-31 17:45 ` Omar Polo
2023-04-02 13:44 ` Ludovic Courtès
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