[SVN-2580] svn+ssh SIGKILLs ssh processes (causing problems for OpenSSH connection multiplexing)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: trunk
• Fix Version/s: 1.6.9
• Component/s: libsvn_ra_svn
• Assignee: Unassigned
• Reporter: Subversion Importer
• Created: 10/Jul/06 08:05
• Updated: 27/Oct/18 16:28
• Resolved: 02/Feb/11 20:26

Description

As discussed [1]:
svn+ssh breaks with ControlSocket Quest (2005-11-04 21:52:58 CET)
and here [2]:
kill(pid_of_ssh, SIGKILL) is rude Alan Barrett (2006-03-21 16:34:40 CET)

the subversion killing of the ssh process has the following deficiencies:
- ssh fails to cleanup sockets [3]
- further ssh commands will fail [4]

The code in subversion/libsvn_ra_svn/client.c indicates:
   *   - Closing the pipes and waiting for the process to die
   *     was prone to mysterious hangs which are difficult to
   *     diagnose (e.g. svnserve dumps core due to unrelated bug;
   *     sshd goes into zombie state; ssh connection is never
   *     closed; ssh never terminates).
   *   - Killing the tunnel agent with SIGTERM leads to unsightly
   *     stderr output from ssh.

The attach patch as suggested by Darren Tucker ([3] comment 10) and 
impliemented bug Damien Miller ([3] comment 13) keeps the SIGTERM and adds 
the -q option to ssh to keep the "unsightly stderr" from interfering with svn.

I have tested this patch against the subversion-1.3.1 in Gentoo and it 
functions correctly (as illistrated by attached straces).

[1] Mentioned here http://svn.haxx.se/users/archive-2005-11/0186.shtml
[2] Mentioned here http://svn.haxx.se/dev/archive-2006-03/0984.shtml
[3] Incorrectly attributed ssh bug 
https://bugzilla.mindrot.org/show_bug.cgi?id=1208
[4] Debian Bug http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=335528

Original issue reported by danielblack