Add pthread_atfork().

PR:  		bin/68841
Submitted by:	Dan Nelson <dnelson@allantgroup.com>

5 files changed, 92 insertions, 1 deletions

diff --git a/lib/libc_r/uthread/Makefile.inc b/lib/libc_r/uthread/Makefile.inc
index 06c5a70..6d457c1 100644
--- a/lib/libc_r/uthread/Makefile.inc
+++ b/lib/libc_r/uthread/Makefile.inc
@@ -10,6 +10,7 @@ SRCS+= \
 	uthread_acl_set_fd.c \
 	uthread_acl_aclcheck_fd.c \
 	uthread_aio_suspend.c \
+	uthread_atfork.c \
 	uthread_attr_destroy.c \
 	uthread_attr_init.c \
 	uthread_attr_getdetachstate.c \
diff --git a/lib/libc_r/uthread/pthread_private.h b/lib/libc_r/uthread/pthread_private.h
index ecd330c..0d49da1 100644
--- a/lib/libc_r/uthread/pthread_private.h
+++ b/lib/libc_r/uthread/pthread_private.h
@@ -451,6 +451,13 @@ struct pthread_cleanup {
 	void			*routine_arg;
 };
 
+struct pthread_atfork {
+	TAILQ_ENTRY(pthread_atfork) qe;
+	void (*prepare)(void);
+	void (*parent)(void);
+	void (*child)(void);
+};
+
 struct pthread_attr {
 	int	sched_policy;
 	int	sched_inherit;
@@ -1025,6 +1032,9 @@ SCLASS struct pthread *_thread_initial
 ;
 #endif
 
+SCLASS TAILQ_HEAD(atfork_head, pthread_atfork)	_atfork_list;
+SCLASS pthread_mutex_t		_atfork_mutex;
+
 /* Default thread attributes: */
 SCLASS struct pthread_attr _pthread_attr_default
 #ifdef GLOBAL_PTHREAD_PRIVATE
diff --git a/lib/libc_r/uthread/uthread_atfork.c b/lib/libc_r/uthread/uthread_atfork.c
new file mode 100644
index 0000000..8a09468
--- /dev/null
+++ b/lib/libc_r/uthread/uthread_atfork.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+#include <errno.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <sys/queue.h>
+#include "pthread_private.h"
+
+__weak_reference(_pthread_atfork, pthread_atfork);
+
+int
+_pthread_atfork(void (*prepare)(void), void (*parent)(void),
+    void (*child)(void))
+{
+	struct pthread_atfork *af;
+
+	if (_thread_initial == NULL)
+		_thread_init();
+
+	if ((af = malloc(sizeof(struct pthread_atfork))) == NULL)
+		return (ENOMEM);
+
+	af->prepare = prepare;
+	af->parent = parent;
+	af->child = child;
+	_pthread_mutex_lock(&_atfork_mutex);
+	TAILQ_INSERT_TAIL(&_atfork_list, af, qe);
+	_pthread_mutex_unlock(&_atfork_mutex);
+	return (0);
+}
+
diff --git a/lib/libc_r/uthread/uthread_fork.c b/lib/libc_r/uthread/uthread_fork.c
index dd6d3ff..0166a57 100644
--- a/lib/libc_r/uthread/uthread_fork.c
+++ b/lib/libc_r/uthread/uthread_fork.c
@@ -48,6 +48,7 @@ pid_t
 _fork(void)
 {
 	struct pthread	*curthread = _get_curthread();
+	struct pthread_atfork *af;
 	int             i, flags, use_deadlist = 0;
 	pid_t           ret;
 	pthread_t	pthread;
@@ -59,9 +60,23 @@ _fork(void)
 	 */
 	_thread_kern_sig_defer();
 
+	_pthread_mutex_lock(&_atfork_mutex);
+
+	/* Run down atfork prepare handlers. */
+	TAILQ_FOREACH_REVERSE(af, &_atfork_list, atfork_head, qe) {
+		if (af->prepare != NULL)
+			af->prepare();
+	}
+
 	/* Fork a new process: */
 	if ((ret = __sys_fork()) != 0) {
-		/* Parent process or error. Nothing to do here. */
+		/* Run down atfork parent handlers. */
+		TAILQ_FOREACH(af, &_atfork_list, qe) {
+			if (af->parent != NULL)
+			af->parent();
+		}
+		_pthread_mutex_unlock(&_atfork_mutex);
+
 	} else {
 		/* Close the pthread kernel pipe: */
 		__sys_close(_thread_kern_pipe[0]);
@@ -207,8 +222,15 @@ _fork(void)
 				}
 			}
 		}
+		/* Run down atfork child handlers. */
+		TAILQ_FOREACH(af, &_atfork_list, qe) {
+			if (af->child != NULL)
+				af->child();
+		}
+		_mutex_reinit(&_atfork_mutex);
 	}
 
+
 	/*
 	 * Undefer and handle pending signals, yielding if necessary:
 	 */
diff --git a/lib/libc_r/uthread/uthread_init.c b/lib/libc_r/uthread/uthread_init.c
index fadc277..1cd39b1 100644
--- a/lib/libc_r/uthread/uthread_init.c
+++ b/lib/libc_r/uthread/uthread_init.c
@@ -437,6 +437,8 @@ _thread_init(void)
 		TAILQ_INIT(&_thread_list);
 		TAILQ_INSERT_HEAD(&_thread_list, _thread_initial, tle);
 		_set_curthread(_thread_initial);
+		TAILQ_INIT(&_atfork_list);
+		_pthread_mutex_init(&_atfork_mutex, NULL);
 
 		/* Initialise the global signal action structure: */
 		sigfillset(&act.sa_mask);