Linux sandbox test: temporarily allow fork() with threads

sandbox/linux/tests/unit_tests.cc

 // Copyright (c) 2012 The Chromium 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 <fcntl.h>
 #include <poll.h>
 #include <signal.h>
 #include <stdio.h>
 #include <sys/resource.h>
 #include <sys/time.h>
@@ skipping 24 matching lines @@
   if (task_d != 0 || task_stat.st_nlink < 3)
     return -1;
   const int num_threads = task_stat.st_nlink - 2;
   return num_threads;
 }
 
 }  // namespace
 
 namespace sandbox {
 
+extern bool kAllowForkWithThreads;
+
 bool IsAndroid() {
 #if defined(OS_ANDROID)
   return true;
 #else
   return false;
 #endif
 }
 
 bool IsArchitectureArm() {
 #if defined(ARCH_CPU_ARM_FAMILY)
@@ skipping 64 matching lines @@
   // there is a way to delay the start of the thread
   // (https://code.google.com/p/thread-sanitizer/issues/detail?id=19).
   const int kNumExpectedThreads = 2;
 #endif
 
   // The kernel is at liberty to wake a thread id futex before updating /proc.
   // If another test running in the same process has stopped a thread, it may
   // appear as still running in /proc.
   // We poll /proc, with an exponential back-off. At most, we'll sleep around
   // 2^iterations nanoseconds in nanosleep().
-  for (unsigned int iteration = 0; iteration < 30; iteration++) {
-    struct timespec ts = {0, 1L << iteration /* nanoseconds */};
-    PCHECK(0 == HANDLE_EINTR(nanosleep(&ts, &ts)));
-    num_threads = CountThreads();
-    if (kNumExpectedThreads == num_threads)
-      break;
+  if (!kAllowForkWithThreads) {
+    for (unsigned int iteration = 0; iteration < 30; iteration++) {
+      struct timespec ts = {0, 1L << iteration /* nanoseconds */};
+      PCHECK(0 == HANDLE_EINTR(nanosleep(&ts, &ts)));
+      num_threads = CountThreads();
+      if (kNumExpectedThreads == num_threads)
+        break;
+    }
   }
 
-  ASSERT_EQ(kNumExpectedThreads, num_threads)
-      << "Running sandbox tests with multiple threads "
-      << "is not supported and will make the tests "
-      << "flaky.\n";
+  const std::string multiple_threads_error =
+      "Running sandbox tests with multiple threads "
+      "is not supported and will make the tests flaky.";
+  if (!kAllowForkWithThreads) {
+    ASSERT_EQ(kNumExpectedThreads, num_threads) << multiple_threads_error;
+  } else {
+    LOG(ERROR) << multiple_threads_error;
+  }
+
   int fds[2];
   ASSERT_EQ(0, pipe(fds));
   // Check that our pipe is not on one of the standard file descriptor.
   SANDBOX_ASSERT(fds[0] > 2 && fds[1] > 2);
 
   pid_t pid;
   ASSERT_LE(0, (pid = fork()));
   if (!pid) {
     // In child process
     // Redirect stderr to our pipe. This way, we can capture all error
@@ skipping 130 matching lines @@
   fflush(stderr);
   _exit(kExitWithAssertionFailure);
 }
 
 void UnitTests::IgnoreThisTest() {
   fflush(stderr);
   _exit(kIgnoreThisTest);
 }
 
 }  // namespace