X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/80e2389990082500d76eb566d4946be3e786c3ef..d8f41ccd20de16f8ebe2ccc84d47bf1cb2b26bbb:/securityd/src/child.cpp

diff --git a/securityd/src/child.cpp b/securityd/src/child.cpp
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+/*
+ * Copyright (c) 2004,2007 Apple Inc. All Rights Reserved.
+ * 
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+
+//
+// child - track a single child process and its belongings
+//
+#include "child.h"
+#include "dtrace.h"
+#include <security_utilities/debugging.h>
+
+
+//
+// We use a static Mutex to coordinate checkin
+//
+Mutex ServerChild::mCheckinLock;
+
+
+//
+// Make and break ServerChildren
+//
+ServerChild::ServerChild()
+	: mCheckinCond(mCheckinLock)
+{
+}
+
+
+//
+// If the ServerChild is destroyed, kill its process, nice or hard.
+//
+// In case you wonder about the tango below, it's making sure we
+// get to "It's dead, Jim" with the minimum number of checkChildren()
+// calls while still working correctly if this is the only thread alive.
+//
+//@@@ We *could* define a "soft shutdown" MIG message to send to all
+//@@@ ServerChildren in this situation.
+//
+ServerChild::~ServerChild()
+{
+	mServicePort.destroy();
+	
+	if (state() == alive) {
+		this->kill(SIGTERM);		// shoot it once
+		checkChildren();			// check for quick death
+		if (state() == alive) {
+			usleep(300000);			// give it some grace
+			if (state() == alive) {	// could have been reaped by another thread
+				checkChildren();	// check again
+				if (state() == alive) {	// it... just... won't... die...
+					this->kill(SIGKILL); // take THAT!
+					checkChildren();
+					if (state() == alive) // stuck zombie
+						abandon();	// leave the body behind
+				}
+			}
+		}
+	}
+}
+
+
+//
+// Parent action during fork: wait until ready or dead, then return
+//
+void ServerChild::parentAction()
+{
+	// wait for either checkin or (premature) death
+	secdebug("serverchild", "%p (pid %d) waiting for checkin", this, pid());
+	StLock<Mutex> _(mCheckinLock);
+	while (!ready() && state() == alive)
+		mCheckinCond.wait();
+
+	// so what happened?
+	if (state() == dead) {
+		// our child died
+		secdebug("serverchild", "%p (pid %d) died before checking in", this, pid());
+		SECURITYD_CHILD_STILLBORN(this->pid());
+	} else if (ready()) {
+		// child has checked in and is ready for service
+		secdebug("serverchild", "%p (pid %d) ready for service on port %d",
+			this, pid(), mServicePort.port());
+		SECURITYD_CHILD_READY(this->pid());
+	} else
+		assert(false);		// how did we ever get here?!
+}
+
+
+//
+// Death action during fork: release the waiting creator thread, if any
+//
+void ServerChild::dying()
+{
+	SECURITYD_CHILD_DYING(this->pid());
+	secdebug("serverchild", "%p is dead; resuming parent thread (if any)", this);
+	mCheckinCond.signal();
+}
+
+
+void ServerChild::checkIn(Port servicePort, pid_t pid)
+{
+	if (ServerChild *child = Child::find<ServerChild>(pid)) {
+		// Child was alive when last seen. Store service port and signal parent thread
+		{
+			StLock<Mutex> _(mCheckinLock);
+			child->mServicePort = servicePort;
+			servicePort.modRefs(MACH_PORT_RIGHT_SEND, +1);	// retain send right
+			secdebug("serverchild", "%p (pid %d) checking in; resuming parent thread",
+				child, pid);
+		}
+		SECURITYD_CHILD_CHECKIN(pid, servicePort);
+		child->mCheckinCond.signal();
+	} else {
+		// Child has died; is wrong kind; or spurious checkin.
+		// If it was a proper child, death notifications will wake up the parent thread
+		secdebug("serverchild", "pid %d not in child set; checkin ignored", pid);
+		SECURITYD_CHILD_CHECKIN(pid, 0);
+	}
+}