pthread_atfork()

2 files changed, 100 insertions, 1 deletions

diff --git a/lib/libpthread/uthread/uthread_atfork.c b/lib/libpthread/uthread/uthread_atfork.c
new file mode 100644
index 00000000000..a3ea65e8288
--- /dev/null
+++ b/lib/libpthread/uthread/uthread_atfork.c
@@ -0,0 +1,93 @@
+/*
+ * David Leonard <d@openbsd.org>, 1999. Public domain.
+ * $OpenBSD: uthread_atfork.c,v 1.1 1999/01/17 23:46:26 d Exp $
+ */
+
+#include <stdlib.h>
+#include <sys/queue.h>
+#ifdef _THREAD_SAFE
+#include <pthread.h>
+#include "pthread_private.h"
+
+struct atfork_entry {
+	void (*handler)(void);
+	TAILQ_ENTRY(atfork_entry) entries;
+};
+
+static TAILQ_HEAD(atfork_list, atfork_entry) atfork_head[3] =
+	{ TAILQ_HEAD_INITIALIZER(atfork_head[PTHREAD_ATFORK_PREPARE]),
+	  TAILQ_HEAD_INITIALIZER(atfork_head[PTHREAD_ATFORK_PARENT]),
+	  TAILQ_HEAD_INITIALIZER(atfork_head[PTHREAD_ATFORK_CHILD]) };
+
+void
+_thread_atfork(which)
+{
+	struct atfork_list *head;
+	struct atfork_entry *ae;
+
+	head = &atfork_head[which];
+
+	/* Call the fork handlers in order: */
+	for (ae = head->tqh_first; ae != NULL; ae = ae->entries.tqe_next)
+		(*ae->handler)();
+}
+
+int
+pthread_atfork(prepare, parent, child)
+	void (*prepare)(void);
+	void (*parent)(void);
+	void (*child)(void);
+{
+	int ret = 0;
+	struct atfork_entry *prepare_entry = NULL;
+	struct atfork_entry *parent_entry = NULL;
+	struct atfork_entry *child_entry = NULL;
+
+	if (ret == 0 && prepare != NULL) {
+		/* Allocate space for the prepare handler: */
+	        if ((prepare_entry = malloc(sizeof *prepare_entry)) != NULL)
+			prepare_entry->handler = prepare;
+	        else
+			ret = -1;
+	}
+
+	if (ret == 0 && parent != NULL) {
+		/* Allocate space for the parent handler: */
+	        if ((parent_entry = malloc(sizeof *parent_entry)) != NULL)
+			parent_entry->handler = parent;
+	        else
+			ret = -1;
+	}
+
+	if (ret == 0 && child != NULL) {
+		/* Allocate space for the child handler: */
+	        if ((child_entry = malloc(sizeof *child_entry)) != NULL)
+			child_entry->handler = child;
+	        else
+			ret = -1;
+	}
+
+	if (ret == 0) {
+		/* Insert the handlers into the handler lists: */
+		if (prepare_entry != NULL)
+			TAILQ_INSERT_HEAD(&atfork_head[PTHREAD_ATFORK_PREPARE],
+			    prepare_entry, entries);
+		if (parent_entry != NULL)
+			TAILQ_INSERT_TAIL(&atfork_head[PTHREAD_ATFORK_PARENT],
+			    parent_entry, entries);
+		if (child_entry != NULL)
+			TAILQ_INSERT_TAIL(&atfork_head[PTHREAD_ATFORK_CHILD],
+			    child_entry, entries);
+	} else {
+		/* Release unused resources: */
+		if (prepare_entry)
+			free(prepare_entry);
+		if (child_entry)
+			free(child_entry);
+		if (parent_entry)
+			free(parent_entry);
+	}
+
+	return (ret);
+}
+#endif
diff --git a/lib/libpthread/uthread/uthread_fork.c b/lib/libpthread/uthread/uthread_fork.c
index 7f532f38adb..913e79e0bdd 100644
--- a/lib/libpthread/uthread/uthread_fork.c
+++ b/lib/libpthread/uthread/uthread_fork.c
@@ -29,7 +29,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $OpenBSD: uthread_fork.c,v 1.3 1999/01/06 05:29:23 d Exp $
+ * $OpenBSD: uthread_fork.c,v 1.4 1999/01/17 23:46:26 d Exp $
  */
 #include <errno.h>
 #include <string.h>
@@ -48,12 +48,17 @@ fork(void)
 	pthread_t	pthread;
 	pthread_t	pthread_next;
 
+	/* Call atfork handlers: */
+	_thread_atfork(PTHREAD_ATFORK_PREPARE);
+
 	/* Lock the thread list: */
 	_lock_thread_list();
 
 	/* Fork a new process: */
 	if ((ret = _thread_sys_fork()) != 0) {
 		/* Parent process or error. Nothing to do here. */
+		if (ret > 0)
+			_thread_atfork(PTHREAD_ATFORK_PARENT);
 	} else {
 		/* Close the pthread kernel pipe: */
 		_thread_sys_close(_thread_kern_pipe[0]);
@@ -121,6 +126,7 @@ fork(void)
 				/* Point to the next thread: */
 				pthread = pthread_next;
 			}
+			_thread_atfork(PTHREAD_ATFORK_CHILD);
 		}
 	}