Add silent option to child_process.fork

Fixes #2354.

doc/api/child_processes.markdown

@@ -229,8 +229,9 @@ And then the child script, `'sub.js'` might look like this:
 In the child the `process` object will have a `send()` method, and `process`
 will emit objects each time it receives a message on its channel.
 
-By default the spawned Node process will have the stdin, stdout, stderr
+By default the spawned Node process will have the stdout, stderr associated
-associated with the parent's.
+with the parent's. To change this behavior set the `silent` property in the
+`options` object to `true`.
 
 These child Nodes are still whole new instances of V8. Assume at least 30ms
 startup and 10mb memory for each new Node. That is, you cannot create many

lib/child_process.js

@@ -158,8 +158,8 @@ exports.fork = function(modulePath, args, options) {
   }
 
   // Leave stdin open for the IPC channel. stdout and stderr should be the
-  // same as the parent's.
+  // same as the parent's if silent isn't set.
-  options.customFds = [-1, 1, 2];
+  options.customFds = (options.silent ? [-1, -1, -1] : [-1, 1, 2]);
 
   // Just need to set this - child process won't actually use the fd.
   // For backwards compat - this can be changed to 'NODE_CHANNEL' before v0.6.

test/simple/test-child-process-silent.js

@@ -0,0 +1,77 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+var assert = require('assert');
+var fork = require('child_process').fork;
+
+var isChild = process.argv[2] === 'child';
+
+if (isChild) {
+  console.log('LOG: a stdout message');
+  console.error('LOG: a stderr message');
+
+  process.send('message from child');
+  process.once('message', function () {
+    process.send('got message from master');
+  });
+
+} else {
+
+  var checks = {
+    stdoutNotPiped: false,
+    stderrNotPiped: false,
+    childSending: false,
+    childReciveing: false
+  };
+
+  var child = fork(process.argv[1], ['child'], { silent: true });
+  child.on('message', function (message) {
+    if (checks.childSending === false) {
+      checks.childSending = (message === 'message from child');
+    }
+
+    if (checks.childReciveing === false) {
+      checks.childReciveing = (message === 'got message from master');
+    }
+
+    if (checks.childReciveing === true) {
+      child.kill();
+    }
+  });
+
+  checks.stdoutNotPiped = (child.stdout && child.stdout.readable === true);
+  checks.stderrNotPiped = (child.stderr && child.stderr.readable === true);
+
+  child.send('message to child');
+
+  //Check all values
+  process.once('exit', function() {
+
+    //Check message system
+    assert.ok(checks.childSending, 'The child was able to send a message');
+    assert.ok(checks.childReciveing, 'The child was able to receive a message');
+
+    //Check std(out|err) pipes
+    assert.ok(checks.stdoutNotPiped, 'The stdout socket was piped to parent');
+    assert.ok(checks.stdoutNotPiped, 'The stderr socket was piped to parent');
+  });
+}