[glib/mcatanzaro/posix-spawn2: 5/12] gspawn: fix hangs when duping child_err_report_fd
- From: Michael Catanzaro <mcatanzaro src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [glib/mcatanzaro/posix-spawn2: 5/12] gspawn: fix hangs when duping child_err_report_fd
- Date: Thu, 28 Oct 2021 00:40:41 +0000 (UTC)
commit 22fa6798fd1858b2cb67af8d05e4f637e556ce56
Author: Michael Catanzaro <mcatanzaro redhat com>
Date: Tue Oct 12 15:33:59 2021 -0500
gspawn: fix hangs when duping child_err_report_fd
In case child_err_report_fd conflicts with one of the target_fds, the
code here is careful to dup child_err_report_fd in order to avoid
conflating the two. It was a good idea, but evidently was not tested,
because the newly-created fd is not created with CLOEXEC set. This means
it stays open in the child process, causing the parent to hang forever
waiting to read from the other end of the pipe. Oops!
The fix is simple: just set CLOEXEC. This removes our only usage of the
safe_dup() function, so it can be dropped.
Fixes #2506
glib/gspawn.c | 16 +---------------
1 file changed, 1 insertion(+), 15 deletions(-)
---
diff --git a/glib/gspawn.c b/glib/gspawn.c
index 9c65d9d92..0deeda8cc 100644
--- a/glib/gspawn.c
+++ b/glib/gspawn.c
@@ -1588,20 +1588,6 @@ safe_closefrom (int lowfd)
#endif
}
-/* This function is called between fork() and exec() and hence must be
- * async-signal-safe (see signal-safety(7)). */
-static gint
-safe_dup (gint fd)
-{
- gint ret;
-
- do
- ret = dup (fd);
- while (ret < 0 && (errno == EINTR || errno == EBUSY));
-
- return ret;
-}
-
/* This function is called between fork() and exec() and hence must be
* async-signal-safe (see signal-safety(7)). */
static gint
@@ -1795,7 +1781,7 @@ do_exec (gint child_err_report_fd,
else
{
if (target_fds[i] == child_err_report_fd)
- child_err_report_fd = safe_dup (child_err_report_fd);
+ child_err_report_fd = dupfd_cloexec (child_err_report_fd);
safe_dup2 (source_fds[i], target_fds[i]);
close_and_invalidate (&source_fds[i]);
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