child_process: Add gid/uid flags to spawn config

This is mostly working, but not completely ideal for two reasons.

1. Rather than emitting an error on the ChildProcess object when the
setgid/setuid fails, it is simply printing the error to stderr and
exiting.  The same happens with the cwd, so that's not completely
terrible.

2. I don't have a good test for this.  It fails with an EPERM if you try
to change the uid or gid as a non-root user.

1 files changed, 11 insertions, 3 deletions

diff --git a/lib/child_process.js b/lib/child_process.js
index e20e80ef0cd..520961fd1a9 100644
--- a/lib/child_process.js
+++ b/lib/child_process.js
@@ -185,21 +185,27 @@ ChildProcess.prototype.kill = function(sig) {
 ChildProcess.prototype.spawn = function(path, args, options, customFds) {
   args = args || [];
 
-  var cwd, env, setsid;
+  var cwd, env, setsid, uid, gid;
   if (!options || options.cwd === undefined &&
       options.env === undefined &&
-      options.customFds === undefined) {
+      options.customFds === undefined &&
+      options.gid === undefined &&
+      options.uid === undefined) {
     // Deprecated API: (path, args, options, env, customFds)
     cwd = '';
     env = options || process.env;
     customFds = customFds || [-1, -1, -1];
     setsid = false;
+    uid = -1;
+    gid = -1;
   } else {
     // Recommended API: (path, args, options)
     cwd = options.cwd || '';
     env = options.env || process.env;
     customFds = options.customFds || [-1, -1, -1];
     setsid = options.setsid ? true : false;
+    uid = options.hasOwnProperty("uid") ? options.uid : -1;
+    gid = options.hasOwnProperty("gid") ? options.gid : -1;
   }
 
   var envPairs = [];
@@ -214,7 +220,9 @@ ChildProcess.prototype.spawn = function(path, args, options, customFds) {
                                  cwd,
                                  envPairs,
                                  customFds,
-                                 setsid);
+                                 setsid,
+                                 uid,
+                                 gid);
   this.fds = fds;
 
   if (customFds[0] === -1 || customFds[0] === undefined) {