Use process_singleton_linux on Mac.

base/process/process_handle_mac.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/process/process_handle.h"
 
+#include <errno.h>

[tapted, 2014/04/08 17:56:44]

nit: I don't think you need all these - maybe just libproc.h?

[jackhou1, 2014/04/14 04:12:10]

Done.

+#include <libproc.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <sys/sysctl.h>
 #include <sys/types.h>
 
 #include "base/logging.h"
 
 namespace base {
 
 ProcessId GetParentProcessId(ProcessHandle process) {
   struct kinfo_proc info;
   size_t length = sizeof(struct kinfo_proc);
   int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process };
   if (sysctl(mib, 4, &info, &length, NULL, 0) < 0) {
     DPLOG(ERROR) << "sysctl";
     return -1;
   }
   if (length == 0)
     return -1;
   return info.kp_eproc.e_ppid;
 }
 
+
+FilePath GetProcessExecutablePath(ProcessHandle process) {
+  char pathbuf[PROC_PIDPATHINFO_MAXSIZE];
+  if (proc_pidpath(process, pathbuf, sizeof(pathbuf)))

[tapted, 2014/04/08 17:56:44]

http://www.opensource.apple.com/source/Libc/Libc-583/darwin/libproc.c seems to
return 0 on error, so this condition doesn't look right.. I can't really find
good documentation for this function though o_O

Is there a test that covers this path?

[jackhou1, 2014/04/14 04:12:10]

You're right. I've inverted the logic and manually confirmed that this method
returns the correct path.

This path is important during the race condition when, while chrome process 0 is
starting up, it writes the SingletonLock symlink, but has not yet connected to
SingletonSocket. Chrome process 1 starts up, fails to connect to the socket, and
reads the symlink for process 0's pid. If that pid's path is not a chrome
binary, process 1 will assume the singleton lock is orphaned and remove it.

There's no test for this case at the moment.

+    return FilePath();
+
+  return FilePath(pathbuf);
+}
+
 }  // namespace base