Revert "Implement pthread_rwlock functions for NaCl newlib."

tests/threads/rwlock_test.c

-/*
- * Copyright 2015 The Native Client Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include <errno.h>
-#include <pthread.h>
-#include <stdio.h>
-#include <time.h>
-
-#include "native_client/src/include/nacl_assert.h"
-
-pthread_rwlock_t g_rwlock;
-volatile int g_thread_has_lock = 0;
-volatile int g_thread_should_acquire_lock = 0;
-volatile int g_thread_should_release_lock = 0;
-
-typedef enum {
-  READ_LOCK = 1,
-  WRITE_LOCK = 2,
-} lock_type;
-
-void *locking_thread(void *unused) {
-  int rc;
-  for (;;) {
-    while (!g_thread_should_acquire_lock) { /* Spin. */ }
-
-    ASSERT_EQ(g_thread_has_lock, 0);
-    if (g_thread_should_acquire_lock == WRITE_LOCK)
-      rc = pthread_rwlock_wrlock(&g_rwlock);
-    else
-      rc = pthread_rwlock_rdlock(&g_rwlock);
-    ASSERT_EQ(rc, 0);
-    __sync_fetch_and_add(&g_thread_has_lock, 1);
-
-    while (!g_thread_should_release_lock) { /* Spin. */ }
-
-    ASSERT_EQ(g_thread_has_lock, 1);
-    rc = pthread_rwlock_unlock(&g_rwlock);
-    ASSERT_EQ(rc, 0);
-    __sync_fetch_and_sub(&g_thread_has_lock, 1);
-  }
-
-  return NULL;
-}
-
-
-void tell_thread_to_acquire_lock(lock_type lock_type) {
-  fprintf(stderr, "Thread acquiring lock: %s\n",
-      lock_type == WRITE_LOCK ? "WRITE" : "READ");
-
-  ASSERT_EQ(g_thread_has_lock, 0);
-  ASSERT_EQ(g_thread_should_acquire_lock, 0);
-  __sync_fetch_and_add(&g_thread_should_acquire_lock, lock_type);
-
-  while (!g_thread_has_lock) { /* Spin. */ }
-
-  __sync_fetch_and_sub(&g_thread_should_acquire_lock, lock_type);
-  ASSERT_EQ(g_thread_should_acquire_lock, 0);
-
-  fprintf(stderr, "Thread acquired lock.\n");
-}
-
-void tell_thread_to_release_lock(void) {
-  fprintf(stderr, "Thread releasing lock.\n");
-
-  ASSERT_EQ(g_thread_has_lock, 1);
-  ASSERT_EQ(g_thread_should_release_lock, 0);
-  __sync_fetch_and_add(&g_thread_should_release_lock, 1);
-
-  while (g_thread_has_lock) { /* Spin. */ }
-
-  __sync_fetch_and_sub(&g_thread_should_release_lock, 1);
-  ASSERT_EQ(g_thread_should_release_lock, 0);
-
-  fprintf(stderr, "Thread released lock.\n");
-}
-
-void test_reader_timedwait(void) {
-  fprintf(stderr, "test_reader_timedwait\n");
-  tell_thread_to_acquire_lock(WRITE_LOCK);
-
-  struct timespec t = { 0, 0 };
-  int rc = pthread_rwlock_timedrdlock(&g_rwlock, &t);
-  ASSERT_EQ(rc, ETIMEDOUT);
-
-  tell_thread_to_release_lock();
-}
-
-void test_writer_timedwait(void) {
-  fprintf(stderr, "test_writer_timedwait\n");
-  tell_thread_to_acquire_lock(READ_LOCK);
-
-  struct timespec t = { 0, 0 };
-  int rc = pthread_rwlock_timedwrlock(&g_rwlock, &t);
-  ASSERT_EQ(rc, ETIMEDOUT);
-
-  tell_thread_to_release_lock();
-}
-
-void test_multiple_writers(void) {
-  fprintf(stderr, "test_multiple_writers\n");
-  tell_thread_to_acquire_lock(WRITE_LOCK);
-
-  /*
-   * Attempt to acquire second write lock should fail.
-   */
-  int rc = pthread_rwlock_trywrlock(&g_rwlock);
-  ASSERT_EQ(rc, EBUSY);
-
-  tell_thread_to_release_lock();
-}
-
-void test_recursive_reader(void) {
-  /*
-   * Test that an rdlock can be recursively acquired even when there
-   * is a waiting writer.
-   */
-  int rc = pthread_rwlock_rdlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-
-  /*
-   * Tell the locking thread to attempt to acquire the write lock.
-   * This should fail and block until all readers are unlocked.
-   */
-  ASSERT_EQ(g_thread_has_lock, 0);
-  ASSERT_EQ(g_thread_should_acquire_lock, 0);
-  __sync_fetch_and_add(&g_thread_should_acquire_lock, WRITE_LOCK);
-
-  /*
-   * Sleep for 10ms
-   */
-  rc = usleep(10 * 1000);
-  ASSERT_EQ(rc, 0);
-  ASSERT_EQ(g_thread_has_lock, 0);
-
-  /*
-   * Now make sure the waiting writer doesn't block the recursive acquisition
-   * of the rdlock (using both tryrdlock and rdlock).
-   */
-  rc = pthread_rwlock_tryrdlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-  rc = pthread_rwlock_unlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-  ASSERT_EQ(g_thread_has_lock, 0);
-  rc = pthread_rwlock_rdlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-  rc = pthread_rwlock_unlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-  ASSERT_EQ(g_thread_has_lock, 0);
-
-  /*
-   * Finally unlock the rdlock which should allow the secondary thread
-   * to acquire the wrlock
-   */
-  rc = pthread_rwlock_unlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-  while (!g_thread_has_lock) { /* Spin. */ }
-  __sync_fetch_and_sub(&g_thread_should_acquire_lock, WRITE_LOCK);
-  ASSERT_EQ(g_thread_should_acquire_lock, 0);
-
-  tell_thread_to_release_lock();
-}
-
-void test_multiple_readers(void) {
-  fprintf(stderr, "test_multiple_readers\n");
-  tell_thread_to_acquire_lock(READ_LOCK);
-
-  /*
-   * Now attempt to acquire the lock on the main thread.
-   * Since they are both readers this should succeed.
-   * Try with tryrdlock, rdlock and timedrdlock.
-   */
-  int rc = pthread_rwlock_tryrdlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-  rc = pthread_rwlock_unlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-
-  struct timespec t = { 0, 0 };
-  rc = pthread_rwlock_timedrdlock(&g_rwlock, &t);
-  ASSERT_EQ(rc, 0);
-  rc = pthread_rwlock_unlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-
-  rc = pthread_rwlock_rdlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-  rc = pthread_rwlock_unlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-
-  tell_thread_to_release_lock();
-}
-
-void test_reader_plus_writer(void) {
-  fprintf(stderr, "test_reader_plus_writer\n");
-  tell_thread_to_acquire_lock(READ_LOCK);
-
-  /*
-   * Now attempt to acquire the write lock on the main thread.
-   * This should fail.
-   */
-  int rc = pthread_rwlock_trywrlock(&g_rwlock);
-  ASSERT_EQ(rc, EBUSY);
-
-  tell_thread_to_release_lock();
-}
-
-void test_writer_plus_reader(void) {
-  fprintf(stderr, "test_writer_plus_reader\n");
-
-  /*
-   * First get the write lock.
-   */
-  int rc = pthread_rwlock_wrlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-
-  /*
-   * Attempt to acquire read lock should now fail
-   */
-  rc = pthread_rwlock_tryrdlock(&g_rwlock);
-  ASSERT_EQ(rc, EBUSY);
-
-  rc = pthread_rwlock_unlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-}
-
-void test_unlocked_with_zero_timestamp(void) {
-  fprintf(stderr, "test_unlocked_with_zero_timestamp\n");
-  int rc;
-  struct timespec abstime = { 0, 0 };
-  ASSERT_EQ(g_thread_has_lock, 0);
-  fprintf(stderr, "Trying to lock the unlocked rwlock with a valid "
-          "zero absolute timestamp. "
-          "Expected to succeed instantly since the lock is free.\n");
-  rc = pthread_rwlock_timedrdlock(&g_rwlock, &abstime);
-  ASSERT_EQ(rc, 0);
-  rc = pthread_rwlock_unlock(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-}
-
-int main(int argc, char **argv) {
-  int rc;
-  fprintf(stderr, "Running...\n");
-
-  pthread_rwlockattr_t attrs;
-  rc = pthread_rwlockattr_init(&attrs);
-  ASSERT_EQ(rc, 0);
-  int shared = -1;
-  rc = pthread_rwlockattr_getpshared(&attrs, &shared);
-  ASSERT_EQ(rc, 0);
-  ASSERT_EQ(shared, PTHREAD_PROCESS_PRIVATE);
-  rc = pthread_rwlockattr_setpshared(&attrs, PTHREAD_PROCESS_SHARED);
-  ASSERT_EQ(rc, 0);
-  rc = pthread_rwlockattr_setpshared(&attrs, PTHREAD_PROCESS_PRIVATE);
-  ASSERT_EQ(rc, 0);
-  rc = pthread_rwlock_init(&g_rwlock, &attrs);
-  ASSERT_EQ(rc, 0);
-  rc = pthread_rwlockattr_destroy(&attrs);
-  ASSERT_EQ(rc, 0);
-
-  pthread_t thread;
-  rc = pthread_create(&thread, NULL, locking_thread, NULL);
-  ASSERT_EQ(rc, 0);
-  fprintf(stderr, "Thread started.\n");
-
-  test_unlocked_with_zero_timestamp();
-  test_multiple_readers();
-  test_multiple_writers();
-  test_reader_plus_writer();
-  test_writer_plus_reader();
-  test_reader_timedwait();
-  test_writer_timedwait();
-  test_recursive_reader();
-
-  rc = pthread_rwlock_destroy(&g_rwlock);
-  ASSERT_EQ(rc, 0);
-  fprintf(stderr, "Done.\n");
-  return 0;
-}