Use 'ps <pid>' to test for process existence if posix is not available

Summary: posix may not be loaded on the web/cgi SAPI but we call posix functions
on this pathway, which we hit on /daemon/. Fall back to exec if we don't have
posix.

Test Plan: Added "&& false" and verified the page executed a bunch of "ps"
tests.

Reviewers: Koolvin, btrahan

Reviewed By: btrahan

CC: aran, epriestley

Maniphest Tasks: T821

Differential Revision: https://secure.phabricator.com/D1540

src/infrastructure/daemon/control/reference/PhabricatorDaemonReference.php

@@ -1,7 +1,7 @@
 <?php
 
 /*
- * Copyright 2011 Facebook, Inc.
+ * Copyright 2012 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -63,15 +63,21 @@ final class PhabricatorDaemonReference {
       return false;
     }
 
-    // This may fail if we can't signal the process because we are running as
-    // a different user (for example, we are 'apache' and the process is some
-    // other user's, or we are a normal user and the process is root's), but
-    // we can check the error code to figure out if the process exists.
-    $is_running = posix_kill($pid, 0);
-    if (posix_get_last_error() == 1) {
-      // "Operation Not Permitted", indicates that the PID exists. If it
-      // doesn't, we'll get an error 3 ("No such process") instead.
-      $is_running = true;
+    if (function_exists('posix_kill')) {
+      // This may fail if we can't signal the process because we are running as
+      // a different user (for example, we are 'apache' and the process is some
+      // other user's, or we are a normal user and the process is root's), but
+      // we can check the error code to figure out if the process exists.
+      $is_running = posix_kill($pid, 0);
+      if (posix_get_last_error() == 1) {
+        // "Operation Not Permitted", indicates that the PID exists. If it
+        // doesn't, we'll get an error 3 ("No such process") instead.
+        $is_running = true;
+      }
+    } else {
+      // If we don't have the posix extension, just exec.
+      list($err) = exec_manual('ps %s', $pid);
+      $is_running = ($err == 0);
     }
 
     return $is_running;

src/infrastructure/daemon/control/reference/__init__.php

@@ -6,6 +6,7 @@
 
 
 
+phutil_require_module('phutil', 'future/exec');
 phutil_require_module('phutil', 'utils');