# HG changeset patch
# User Siddharth Agarwal <sid0@fb.com>
# Date 2013-10-02 22:20:49
# Node ID 0532c8f8e911d374a08b71ae1426ec0ef664dab3
# Parent  edce20ebe1f3434367796747f802fe74e23ede9b

cmdutil.service: move pidfile writing to the parent in daemon mode

There is a potential race here, which I suspect I've spotted in the wild, where
something reads the pid file after the parent exits but before the child has
had a chance to write to it. Moving writing the file to the parent causes this
to no longer be an issue.

diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -497,6 +497,7 @@ def service(opts, parentfn=None, initfn=
             pid = util.rundetached(runargs, condfn)
             if pid < 0:
                 raise util.Abort(_('child process failed to start'))
+            writepid(pid)
         finally:
             try:
                 os.unlink(lockpath)
@@ -511,7 +512,8 @@ def service(opts, parentfn=None, initfn=
     if initfn:
         initfn()
 
-    writepid(os.getpid())
+    if not opts['daemon']:
+        writepid(os.getpid())
 
     if opts['daemon_pipefds']:
         lockpath = opts['daemon_pipefds']