Attachment 14445 Details for Bug 13578 – git-am fix for 4.9.next, 4.8.next, 4.7.next

[patch] git-am fix for 4.9.next, 4.8.next, 4.7.next

0001-s3-util-Do-not-take-over-stderr-when-there-is-no-log.patch (text/plain), 2.59 KB, created by Jeremy Allison on 2018-08-23 22:35:00 UTC

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Creator: Jeremy Allison

Created: 2018-08-23 22:35:00 UTC

Size: 2.59 KB

patch

obsolete

>From a62adedbbd7f3584d5e51d969e49b241706108a1 Mon Sep 17 00:00:00 2001
>From: Paulo Alcantara <paulo@paulo.ac>
>Date: Fri, 17 Aug 2018 11:30:16 -0300
>Subject: [PATCH] s3: util: Do not take over stderr when there is no log file
>
>In case we don't have either a /var/log/samba directory, or pass a
>non-existent log directory through '-l' option, all commands that are
>daemonized with '-D' option hang when executed within a subshell.
>
>An example on how to trigger that:
>
>  # rm -r /var/log/samba
>  # s=$(nmbd -D -s /etc/samba/smb.conf -l /foo123)
>  (never returns)
>
>So, when the above command is executed within a subshell the following
>happens:
>
>  (a) Parent shell creates a pipe, sets write side of it to fd 1
>    (stdout), call read() on read-side fd, forks off a new child process
>    and then executes nmbd in it.
>  (b) nmbd sets up initial logging to go through fd 1 (stdout) by
>    calling setup_logging(..., DEBUG_DEFAULT_STDOUT). 'state.fd' is now
>    set to 1.
>  (c) reopen_logs() is called by the first time which then calls
>    reopen_logs_internal()
>  (d) in reopen_logs_internal(), it attempts to create log.nmbd file in
>    /foo123 directory and fails because directory doesn't exist.
>  (e) Regardless whether the log file was created or not, it calls
>    dup2(state.fd, 2) which dups fd 1 into fd 2.
>  (f) At some point, fd 0 and 1 are closed and set to /dev/null
>
>The problem with that is because parent shell in (a) is still blocked in
>read() call and the new write side of the pipe is now fd 2 -- after
>dup2() in (e) -- and remains unclosed.
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=13578
>
>Signed-off-by: Paulo Alcantara <palcantara@suse.de>
>Reviewed-by: Jim McDonough <jmcd@samba.org>
>Reviewed-by: Jeremy Allison <jra@samba.org>
>
>Autobuild-User(master): Jeremy Allison <jra@samba.org>
>Autobuild-Date(master): Sat Aug 18 01:32:25 CEST 2018 on sn-devel-144
>
>(cherry picked from commit 41aa55f49233ea7682cf14e5a7062617274434ce)
>---
> lib/util/debug.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
>diff --git a/lib/util/debug.c b/lib/util/debug.c
>index 141f3a595ca..d41e0f99c77 100644
>--- a/lib/util/debug.c
>+++ b/lib/util/debug.c
>@@ -1077,8 +1077,11 @@ bool reopen_logs_internal(void)
> 	force_check_log_size();
> 	(void)umask(oldumask);
> 
>-	/* Take over stderr to catch output into logs */
>-	if (state.fd > 0) {
>+	/*
>+	 * If log file was opened or created successfully, take over stderr to
>+	 * catch output into logs.
>+	 */
>+	if (new_fd != -1) {
> 		if (dup2(state.fd, 2) == -1) {
> 			/* Close stderr too, if dup2 can't point it -
> 			   at the logfile.  There really isn't much
>-- 
>2.18.0.1017.ga543ac7ca45-goog
>

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jmcd: review+

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Attachments on bug 13578: 14430 | 14445