From f82005655962a206f06230d55bfffdd913228c0a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20Ma=C5=82ecki?= <maciej.malecki@notimplemented.org>
Date: Mon, 10 Oct 2011 21:22:38 +0200
Subject: [PATCH] [fix] Use `process.kill` to check if process is alive

Old solution spawned `ps <pid> | grep -v PID` to perform this check.
---
 lib/forever.js | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/lib/forever.js b/lib/forever.js
index de71f82d..73ba778d 100644
--- a/lib/forever.js
+++ b/lib/forever.js
@@ -853,13 +853,18 @@ forever.checkProcess = function (pid, callback) {
     return callback(false);
   }
 
-  exec('ps ' + pid + ' | grep -v PID', function (err, stdout, stderr) {
-    if (err) {
-      return callback(false);
-    }
-
-    callback(stdout.indexOf(pid) !== -1);
-  });
+  try {
+    //
+    // Trying to kill non-existent process here raises a ESRCH - no such
+    // process exception. Also, signal 0 doesn't do no harm to a process - it
+    // only checks if sending a singal to a given process is possible.
+    //
+    process.kill(pid, 0);
+    callback(true);
+  }
+  catch (err) {
+    callback(false);
+  }
 };
 
 //
@@ -910,4 +915,4 @@ forever.columns = {
       return timespan.fromDates(new Date(proc.ctime), new Date()).toString().yellow;
     }
   }
-};
\ No newline at end of file
+};