Add pthread_atfork(3)

From FreeBSD

'looks ok' fgsch@ miod@
man page reviewed by jmc@

5 files changed, 96 insertions, 5 deletions

diff --git a/lib/libpthread/uthread/Makefile.inc b/lib/libpthread/uthread/Makefile.inc
index 02c07c5481b..6ef4e88c344 100644
--- a/lib/libpthread/uthread/Makefile.inc
+++ b/lib/libpthread/uthread/Makefile.inc
@@ -1,4 +1,4 @@
-# $OpenBSD: Makefile.inc,v 1.18 2004/02/22 23:59:26 brad Exp $
+# $OpenBSD: Makefile.inc,v 1.19 2005/10/30 03:37:34 brad Exp $
 # $FreeBSD: Makefile.inc,v 1.19 1999/08/28 00:03:19 peter Exp $
 
 # uthread sources
@@ -8,6 +8,7 @@ CFLAGS += -I${SRCDIR}/arch/${MACHINE_ARCH}
 
 SRCS+= \
 	uthread_accept.c \
+	uthread_atfork.c \
 	uthread_attr_destroy.c \
 	uthread_attr_init.c \
 	uthread_attr_getdetachstate.c \
diff --git a/lib/libpthread/uthread/pthread_private.h b/lib/libpthread/uthread/pthread_private.h
index aef55382c95..bfb038aa671 100644
--- a/lib/libpthread/uthread/pthread_private.h
+++ b/lib/libpthread/uthread/pthread_private.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pthread_private.h,v 1.53 2004/06/07 21:11:23 marc Exp $	*/
+/*	$OpenBSD: pthread_private.h,v 1.54 2005/10/30 03:37:34 brad Exp $	*/
 /*
  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>.
  * All rights reserved.
@@ -345,6 +345,13 @@ 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;
@@ -901,6 +908,9 @@ 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/libpthread/uthread/uthread_atfork.c b/lib/libpthread/uthread/uthread_atfork.c
new file mode 100644
index 00000000000..10e6f6be25b
--- /dev/null
+++ b/lib/libpthread/uthread/uthread_atfork.c
@@ -0,0 +1,58 @@
+/*	$OpenBSD: uthread_atfork.c,v 1.3 2005/10/30 03:37:34 brad Exp $	*/
+
+/*
+ * 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: /repoman/r/ncvs/src/lib/libc_r/uthread/uthread_atfork.c,v 1.1 2004/12/10 03:36:45 grog Exp $
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#ifdef _THREAD_SAFE
+#include <pthread.h>
+#include <sys/queue.h>
+#include "pthread_private.h"
+
+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);
+}
+#endif
diff --git a/lib/libpthread/uthread/uthread_fork.c b/lib/libpthread/uthread/uthread_fork.c
index 02f7656859b..09a3279392a 100644
--- a/lib/libpthread/uthread/uthread_fork.c
+++ b/lib/libpthread/uthread/uthread_fork.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uthread_fork.c,v 1.11 2003/08/06 21:08:05 millert Exp $	*/
+/*	$OpenBSD: uthread_fork.c,v 1.12 2005/10/30 03:37:34 brad Exp $	*/
 /*
  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
  * All rights reserved.
@@ -45,6 +45,7 @@ pid_t
 fork(void)
 {
 	struct pthread	*curthread = _get_curthread();
+	struct pthread_atfork *af;
 	int             i, flags;
 	pid_t           ret;
 	pthread_t	pthread;
@@ -55,9 +56,22 @@ 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 = _thread_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: */
 		_thread_sys_close(_thread_kern_pipe[0]);
@@ -178,6 +192,12 @@ fork(void)
 				}
 			}
 		}
+		/* Run down atfork child handlers. */
+		TAILQ_FOREACH(af, &_atfork_list, qe) {
+			if (af->child != NULL)
+				af->child();
+		}
+		_mutex_reinit(&_atfork_mutex);
 	}
 
 	/*
diff --git a/lib/libpthread/uthread/uthread_init.c b/lib/libpthread/uthread/uthread_init.c
index 531753880e6..69a70e5a22a 100644
--- a/lib/libpthread/uthread/uthread_init.c
+++ b/lib/libpthread/uthread/uthread_init.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uthread_init.c,v 1.32 2004/06/07 21:11:23 marc Exp $	*/
+/*	$OpenBSD: uthread_init.c,v 1.33 2005/10/30 03:37:34 brad Exp $	*/
 /*
  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
  * All rights reserved.
@@ -289,6 +289,8 @@ _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);