<pthread.h> fixes and pthread cleanup.
<pthread.h> was missing nonnull attributes, noreturn on pthread_exit,
and had incorrect cv qualifiers for several standard functions.
I've also marked the non-standard stuff (where I count glibc rather
than POSIX as "standard") so we can revisit this cruft for LP64 and
try to ensure we're compatible with glibc.
I've also broken out the pthread_cond* functions into a new file.
I've made the remaining pthread files (plus ptrace) part of the bionic code
and fixed all the warnings.
I've added a few more smoke tests for chunks of untested pthread functionality.
We no longer need the libc_static_common_src_files hack for any of the
pthread implementation because we long since stripped out the rest of
the armv5 support, and this hack was just to ensure that __get_tls in libc.a
went via the kernel if necessary.
This patch also finishes the job of breaking up the pthread.c monolith, and
adds a handful of new tests.
Change-Id: Idc0ae7f5d8aa65989598acd4c01a874fe21582c7
diff --git a/libc/bionic/pthread_once.cpp b/libc/bionic/pthread_once.cpp
new file mode 100644
index 0000000..6d9d7d1
--- /dev/null
+++ b/libc/bionic/pthread_once.cpp
@@ -0,0 +1,100 @@
+/*
+ * 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 <pthread.h>
+
+#include "private/bionic_atomic_inline.h"
+#include "private/bionic_futex.h"
+
+#define ONCE_INITIALIZING (1 << 0)
+#define ONCE_COMPLETED (1 << 1)
+
+/* NOTE: this implementation doesn't support a init function that throws a C++ exception
+ * or calls fork()
+ */
+int pthread_once(pthread_once_t* once_control, void (*init_routine)(void)) {
+ volatile pthread_once_t* once_control_ptr = once_control;
+
+ // PTHREAD_ONCE_INIT is 0, we use the following bit flags
+ // bit 0 set -> initialization is under way
+ // bit 1 set -> initialization is complete
+
+ // First check if the once is already initialized. This will be the common
+ // case and we want to make this as fast as possible. Note that this still
+ // requires a load_acquire operation here to ensure that all the
+ // stores performed by the initialization function are observable on
+ // this CPU after we exit.
+ if (__predict_true((*once_control_ptr & ONCE_COMPLETED) != 0)) {
+ ANDROID_MEMBAR_FULL();
+ return 0;
+ }
+
+ while (true) {
+ // Try to atomically set the INITIALIZING flag.
+ // This requires a cmpxchg loop, and we may need
+ // to exit prematurely if we detect that
+ // COMPLETED is now set.
+ int32_t old_value, new_value;
+
+ do {
+ old_value = *once_control_ptr;
+ if ((old_value & ONCE_COMPLETED) != 0) {
+ break;
+ }
+
+ new_value = old_value | ONCE_INITIALIZING;
+ } while (__bionic_cmpxchg(old_value, new_value, once_control_ptr) != 0);
+
+ if ((old_value & ONCE_COMPLETED) != 0) {
+ // We detected that COMPLETED was set while in our loop.
+ ANDROID_MEMBAR_FULL();
+ return 0;
+ }
+
+ if ((old_value & ONCE_INITIALIZING) == 0) {
+ // We got there first, we can jump out of the loop to handle the initialization.
+ break;
+ }
+
+ // Another thread is running the initialization and hasn't completed
+ // yet, so wait for it, then try again.
+ __futex_wait_ex(once_control_ptr, 0, old_value, NULL);
+ }
+
+ // Call the initialization function.
+ (*init_routine)();
+
+ // Do a store_release indicating that initialization is complete.
+ ANDROID_MEMBAR_FULL();
+ *once_control_ptr = ONCE_COMPLETED;
+
+ // Wake up any waiters, if any.
+ __futex_wake_ex(once_control_ptr, 0, INT_MAX);
+
+ return 0;
+}