Implemented pthread_atfork()android-sdk-tools_r7android-adt-0.9.8

Change-Id: Ie6c0bf593315d3507b3c4a6c8903a74a1fa053db

1 files changed, 123 insertions, 0 deletions

diff --git a/libc/bionic/pthread-atfork.c b/libc/bionic/pthread-atfork.c
new file mode 100644
index 000000000..3a5189d8c
--- /dev/null
+++ b/libc/bionic/pthread-atfork.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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.
+ */
+#include <stdlib.h>
+#include <errno.h>
+#include <pthread.h>
+#include <sys/queue.h>
+
+static pthread_mutex_t handler_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER;
+
+struct atfork_t
+{
+    CIRCLEQ_ENTRY(atfork_t) entries;
+
+    void (*prepare)(void);
+    void (*child)(void);
+    void (*parent)(void);
+};
+static CIRCLEQ_HEAD(atfork_head_t, atfork_t) atfork_head = \
+    CIRCLEQ_HEAD_INITIALIZER(atfork_head);
+
+void __bionic_atfork_run_prepare()
+{
+    struct atfork_t *cursor;
+
+    /* We will lock this here, and unlock it in the parent and child functions.
+     * This ensures that nobody can modify the handler array between the calls
+     * to the prepare and parent/child handlers.
+     *
+     * TODO: If a handler mucks with the list, it could cause problems.  Right
+     *       now it's ok because all they can do is add new items to the end
+     *       of the list, but if/when we implement cleanup in dlclose() things
+     *       will get more interesting...
+     */
+    pthread_mutex_lock(&handler_mutex);
+
+    /* Call pthread_atfork() prepare handlers.  Posix states that the prepare
+     * handlers should be called in the reverse order of the parent/child
+     * handlers, so we iterate backwards.
+     */
+    for (cursor = atfork_head.cqh_last;
+         cursor != (void*)&atfork_head;
+         cursor = cursor->entries.cqe_prev) {
+        if (cursor->prepare != NULL) {
+            cursor->prepare();
+        }
+    }
+}
+
+void __bionic_atfork_run_child()
+{
+    struct atfork_t *cursor;
+
+    /* Call pthread_atfork() child handlers */
+    for (cursor = atfork_head.cqh_first;
+         cursor != (void*)&atfork_head;
+         cursor = cursor->entries.cqe_next) {
+        if (cursor->child != NULL) {
+            cursor->child();
+        }
+    }
+
+    pthread_mutex_unlock(&handler_mutex);
+}
+
+void __bionic_atfork_run_parent()
+{
+    struct atfork_t *cursor;
+
+    /* Call pthread_atfork() parent handlers */
+    for (cursor = atfork_head.cqh_first;
+         cursor != (void*)&atfork_head;
+         cursor = cursor->entries.cqe_next) {
+        if (cursor->parent != NULL) {
+            cursor->parent();
+        }
+    }
+
+    pthread_mutex_unlock(&handler_mutex);
+}
+
+int pthread_atfork(void (*prepare)(void), void (*parent)(void), void(*child)(void))
+{
+    struct atfork_t *entry = malloc(sizeof(struct atfork_t));
+
+    if (entry == NULL) {
+        return ENOMEM;
+    }
+
+    entry->prepare = prepare;
+    entry->parent = parent;
+    entry->child = child;
+
+    pthread_mutex_lock(&handler_mutex);
+    CIRCLEQ_INSERT_TAIL(&atfork_head, entry, entries);
+    pthread_mutex_unlock(&handler_mutex);
+
+    return 0;
+}