GNU bug report logs - #62334
Guile's "sleep pipe" can leak into processes created by 'spawn'

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From: Josselin Poiret <dev <at> jpoiret.xyz>
To: Ludovic Courtès <ludo <at> gnu.org>, Josselin Poiret <dev <at> jpoiret.xyz>
Cc: 63024 <at> debbugs.gnu.org, 62334 <at> debbugs.gnu.org, Greg Hogan <code <at> greghogan.com>, Simon Tournier <zimon.toutoune <at> gmail.com>
Subject: bug#62334: [PATCH 1/3] Add error handling for spawn's posix_spawn_file_actions_adddup2
Date: Fri,  5 May 2023 15:39:22 +0200

From: Josselin Poiret <dev <at> jpoiret.xyz>

* libguile/posix.c (do_spawn): Add error handling if
posix_spawn_file_actions_adddup2 fails.
---
Hi Ludo,

Sorry for not noticing this thread sooner!  Here's my take on it, a minor
variation but that's what I'd prefer tbh.

LMKWYT,
Josselin

 libguile/posix.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/libguile/posix.c b/libguile/posix.c
index 3adc743c4..2969f1f24 100644
--- a/libguile/posix.c
+++ b/libguile/posix.c
@@ -1390,12 +1390,15 @@ do_spawn (char *exec_file, char **exec_argv, char **exec_env,
   /* Move the fds out of the way, so that duplicate fds or fds equal
      to 0, 1, 2 don't trample each other */
 
-  posix_spawn_file_actions_adddup2 (&actions, in, fd_slot[0]);
-  posix_spawn_file_actions_adddup2 (&actions, out, fd_slot[1]);
-  posix_spawn_file_actions_adddup2 (&actions, err, fd_slot[2]);
-  posix_spawn_file_actions_adddup2 (&actions, fd_slot[0], 0);
-  posix_spawn_file_actions_adddup2 (&actions, fd_slot[1], 1);
-  posix_spawn_file_actions_adddup2 (&actions, fd_slot[2], 2);
+  int dup2_action_from[] = {in, out, err,
+                            fd_slot[0], fd_slot[1], fd_slot[2]};
+  int dup2_action_to  [] = {fd_slot[0], fd_slot[1], fd_slot[2],
+                            0, 1, 2};
+
+  errno = 0;
+  for (int i = 0;i < sizeof (dup2_action_from) / sizeof (int);i++)
+    if ((errno = posix_spawn_file_actions_adddup2 (&actions, dup2_action_from[i], dup2_action_to[i])))
+        return -1;
 
 #ifdef HAVE_ADDCLOSEFROM
   /* This function appears in glibc 2.34.  It's both free from race

base-commit: fe6cc6d04ab094ea802907bdc4f728416c0e97ba
-- 
2.39.2

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