diff --git a/src/daemon/PhutilDaemonOverseer.php b/src/daemon/PhutilDaemonOverseer.php
index a4f37aa..b7f6d99 100644
--- a/src/daemon/PhutilDaemonOverseer.php
+++ b/src/daemon/PhutilDaemonOverseer.php
@@ -1,361 +1,409 @@
 <?php
 
 /**
  * Oversees a daemon and restarts it if it fails.
  *
  * @group daemon
  */
 final class PhutilDaemonOverseer {
 
   const HEARTBEAT_WAIT = 120;
 
   private $captureBufferSize = 65536;
 
   private $deadline;
   private $deadlineTimeout  = 86400;
   private $restartDelay     = 60;
   private $killDelay        = 3;
   private $heartbeat;
 
   private $daemon;
   private $argv;
   private $childPID;
   private $signaled;
   private static $instance;
 
   private $traceMode;
   private $traceMemory;
   private $daemonize;
   private $phddir;
   private $conduit;
   private $conduitURI;
   private $verbose;
 
   public function __construct(array $argv) {
     PhutilServiceProfiler::getInstance()->enableDiscardMode();
 
     $original_argv = $argv;
     $args = new PhutilArgumentParser($argv);
     $args->setTagline('daemon overseer');
     $args->setSynopsis(<<<EOHELP
 **launch_daemon.php** [__options__] __daemon__
     Launch and oversee an instance of __daemon__.
 EOHELP
       );
     $args->parsePartial(
       array(
         array(
           'name' => 'trace',
           'help' => 'Enable debug tracing.',
         ),
         array(
           'name' => 'trace-memory',
           'help' => 'Enable debug memory tracing.',
         ),
         array(
           'name'  => 'log',
           'param' => 'file',
           'help'  => 'Send output to __file__.',
         ),
         array(
           'name'  => 'daemonize',
           'help'  => 'Run in the background.',
         ),
         array(
           'name'  => 'phd',
           'param' => 'dir',
           'help'  => 'Write PID information to __dir__.',
         ),
         array(
           'name'  => 'conduit-uri',
           'param' => 'uri',
           'help'  => 'Send logs to Conduit on __uri__.'
         ),
         array(
           'name'  => 'verbose',
           'help'  => 'Enable verbose activity logging.',
         ),
       ));
     $argv = $args->getUnconsumedArgumentVector();
 
     $this->daemon = array_shift($argv);
     if (!$this->daemon) {
       $args->printHelpAndExit();
     }
 
     if ($args->getArg('trace')) {
       $this->traceMode = true;
       array_unshift($argv, '--trace');
     }
 
     if ($args->getArg('trace-memory')) {
       $this->traceMode = true;
       $this->traceMemory = true;
       array_unshift($argv, '--trace-memory');
     }
 
     $log = $args->getArg('log');
     if ($log) {
       ini_set('error_log', $log);
       array_unshift($argv, '--log='.$log);
     }
 
     $verbose = $args->getArg('verbose');
     if ($verbose) {
       $this->verbose = true;
       array_unshift($argv, '--verbose');
     }
 
     $this->daemonize  = $args->getArg('daemonize');
     $this->phddir     = $args->getArg('phd');
     $this->conduitURI = $args->getArg('conduit-uri');
     $this->argv       = $argv;
 
     error_log("Bringing daemon '{$this->daemon}' online...");
 
     if (self::$instance) {
       throw new Exception(
         "You may not instantiate more than one Overseer per process.");
     }
 
     self::$instance = $this;
 
     if ($this->daemonize) {
 
       // We need to get rid of these or the daemon will hang when we TERM it
       // waiting for something to read the buffers. TODO: Learn how unix works.
       fclose(STDOUT);
       fclose(STDERR);
       ob_start();
 
       $pid = pcntl_fork();
       if ($pid === -1) {
         throw new Exception("Unable to fork!");
       } else if ($pid) {
         exit(0);
       }
     }
 
     if ($this->phddir) {
       $desc = array(
         'name'            => $this->daemon,
         'pid'             => getmypid(),
         'start'           => time(),
       );
       Filesystem::writeFile(
         $this->phddir.'/daemon.'.getmypid(),
         json_encode($desc));
     }
 
     if ($this->conduitURI) {
       $this->conduit = new ConduitClient($this->conduitURI);
       $this->daemonLogID = $this->conduit->callMethodSynchronous(
         'daemon.launched',
         array(
           'daemon'  => $this->daemon,
           'host'    => php_uname('n'),
           'pid'     => getmypid(),
           'argv'    => json_encode(array_slice($original_argv, 1)),
         ));
     }
 
     declare(ticks = 1);
     pcntl_signal(SIGUSR1, array($this, 'didReceiveKeepaliveSignal'));
 
     pcntl_signal(SIGINT,  array($this, 'didReceiveTerminalSignal'));
     pcntl_signal(SIGTERM, array($this, 'didReceiveTerminalSignal'));
   }
 
   public function run() {
     if ($this->shouldRunSilently()) {
       echo "Running daemon '{$this->daemon}' silently. Use '--trace' or ".
            "'--verbose' to produce debugging output.\n";
     }
 
     $root = phutil_get_library_root('phutil');
     $root = dirname($root);
 
     $exec_dir = $root.'/scripts/daemon/exec/';
 
     // NOTE: PHP implements proc_open() by running 'sh -c'. On most systems this
     // is bash, but on Ubuntu it's dash. When you proc_open() using bash, you
     // get one new process (the command you ran). When you proc_open() using
     // dash, you get two new processes: the command you ran and a parent
     // "dash -c" (or "sh -c") process. This means that the child process's PID
     // is actually the 'dash' PID, not the command's PID. To avoid this, use
     // 'exec' to replace the shell process with the real process; without this,
     // the child will call posix_getppid(), be given the pid of the 'sh -c'
     // process, and send it SIGUSR1 to keepalive which will terminate it
     // immediately. We also won't be able to do process group management because
     // the shell process won't properly posix_setsid() so the pgid of the child
     // won't be meaningful.
 
     $exec_daemon = './exec_daemon.php';
     $argv = $this->argv;
     array_unshift($argv, 'exec', $exec_daemon, $this->daemon);
     foreach ($argv as $k => $arg) {
       $argv[$k] = escapeshellarg($arg);
     }
 
     $command = implode(' ', $argv);
 
     while (true) {
       $this->logMessage('INIT', 'Starting process.');
 
       $future = new ExecFuture('%C', $command);
       $future->setCWD($exec_dir);
       $future->setStdoutSizeLimit($this->captureBufferSize);
       $future->setStderrSizeLimit($this->captureBufferSize);
 
       $this->deadline = time() + $this->deadlineTimeout;
       $this->heartbeat = time() + self::HEARTBEAT_WAIT;
 
       $future->isReady();
       $this->childPID = $future->getPID();
 
       do {
         do {
           if ($this->traceMemory) {
             $memuse = number_format(memory_get_usage() / 1024, 1);
             $this->logMessage('RAMS', 'Overseer Memory Usage: '.$memuse.' KB');
           }
 
           // We need a shortish timeout here so we can run the tick handler
           // frequently in order to process signals.
           $result = $future->resolve(1);
 
           list($stdout, $stderr) = $future->read();
           $stdout = trim($stdout);
           $stderr = trim($stderr);
           if (strlen($stdout)) {
             $this->logMessage('STDO', $stdout, $stdout);
           }
           if (strlen($stderr)) {
             $this->logMessage('STDE', $stderr, $stderr);
           }
           $future->discardBuffers();
 
           if ($result !== null) {
             list($err) = $result;
             if ($err) {
               $this->logMessage(
                 'FAIL',
                 'Process exited with error '.$err.'.',
                 $err);
             } else {
               $this->logMessage('DONE', 'Process exited successfully.');
             }
             break 2;
           }
           if ($this->heartbeat < time()) {
             $this->heartbeat = time() + self::HEARTBEAT_WAIT;
             if ($this->conduitURI) {
               try {
                 $this->conduit = new ConduitClient($this->conduitURI);
                 $this->conduit->callMethodSynchronous(
                   'daemon.setstatus',
                   array(
                     'daemonLogID'  => $this->daemonLogID,
                     'status'       => 'run',
                   ));
               } catch (Exception $ex) {
               }
             }
           }
         } while (time() < $this->deadline);
 
         $this->logMessage('HANG', 'Hang detected. Restarting process.');
         $this->annihilateProcessGroup();
       } while (false);
 
       $this->logMessage('WAIT', 'Waiting to restart process.');
       sleep($this->restartDelay);
     }
   }
 
   public function didReceiveKeepaliveSignal($signo) {
     $this->deadline = time() + $this->deadlineTimeout;
   }
 
   public function didReceiveTerminalSignal($signo) {
     if ($this->signaled) {
       exit(128 + $signo);
     }
 
     echo "\n>>> Shutting down...\n";
     fflush(STDOUT);
     fflush(STDERR);
     fclose(STDOUT);
     fclose(STDERR);
     $this->signaled = true;
     $this->annihilateProcessGroup();
 
     if ($this->conduitURI) {
       try {
         $this->conduit = new ConduitClient($this->conduitURI);
         $this->conduit->callMethodSynchronous(
           'daemon.setstatus',
           array(
             'daemonLogID'  => $this->daemonLogID,
             'status'       => 'exit',
           ));
       } catch (Exception $ex) {
       }
     }
     exit(128 + $signo);
   }
 
   private function logMessage($type, $message, $remote = null) {
     if (!$this->shouldRunSilently()) {
       echo date('Y-m-d g:i:s A').' ['.$type.'] '.$message."\n";
     }
     if ($this->conduit) {
       // TODO: This is kind of sketchy to do without any timeouts since a
       // conduit server hang could throw a wrench into things.
       try {
         $this->conduit->callMethodSynchronous(
           'daemon.log',
           array(
             'daemonLogID'  => $this->daemonLogID,
             'type'         => $type,
             'message'      => $remote,
           ));
       } catch (Exception $ex) {
         // TOOD: Send this somewhere useful instead of eating it.
       }
     }
   }
 
   private function shouldRunSilently() {
     if ($this->traceMode || $this->verbose) {
       return false;
     } else {
       return true;
     }
   }
 
   private function annihilateProcessGroup() {
     $pid = $this->childPID;
     $pgid = posix_getpgid($pid);
     if ($pid && $pgid) {
 
       // NOTE: On Ubuntu, 'kill' does not recognize the use of "--" to
       // explicitly delineate PID/PGIDs from signals. We don't actually need it,
       // so use the implicit "kill -TERM -pgid" form instead of the explicit
       // "kill -TERM -- -pgid" form.
       exec("kill -TERM -{$pgid}");
       sleep($this->killDelay);
 
       // On OSX, we'll get a permission error on stderr if the SIGTERM was
       // successful in ending the life of the process group, presumably because
       // all that's left is the daemon itself as a zombie waiting for us to
       // reap it. However, we still need to issue this command for process
       // groups that resist SIGTERM. Rather than trying to figure out if the
       // process group is still around or not, just SIGKILL unconditionally and
       // ignore any error which may be raised.
       exec("kill -KILL -{$pgid} 2>/dev/null");
       $this->childPID = null;
     }
   }
 
+
+  /**
+   * Identify running daemons by examining the process table. This isn't
+   * completely reliable, but can be used as a fallback if the pid files fail
+   * or we end up with stray daemons by other means.
+   *
+   * Example output (array keys are process IDs):
+   *
+   *   array(
+   *     12345 => array(
+   *       'type' => 'overseer',
+   *       'command' => 'php launch_daemon.php --daemonize ...',
+   *     ),
+   *     12346 => array(
+   *       'type' => 'daemon',
+   *       'command' => 'php exec_daemon.php ...',
+   *     ),
+   *  );
+   *
+   * @return dict   Map of PIDs to process information, identifying running
+   *                daemon processes.
+   */
+  public static function findRunningDaemons() {
+    $results = array();
+
+    list($err, $processes) = exec_manual('ps -o pid,command -a -x -w -w -w');
+    if ($err) {
+      return $results;
+    }
+
+    $processes = array_filter(explode("\n", trim($processes)));
+    foreach ($processes as $process) {
+      list($pid, $command) = explode(' ', $process, 2);
+
+      $matches = null;
+      if (!preg_match('/(launch|exec)_daemon.php/', $command, $matches)) {
+        continue;
+      }
+
+      $results[(int)$pid] = array(
+        'type'    => ($matches[1] == 'launch') ? 'overseer' : 'daemon',
+        'command' => $command,
+      );
+    }
+
+    return $results;
+  }
+
 }