Add routine to close file descriptors on exec

base/process_util_unittest.cc

 // Copyright (c) 2006-2008 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.
 
 #define _CRT_SECURE_NO_WARNINGS
 
 #include "base/multiprocess_test.h"
 #include "base/platform_thread.h"
 #include "base/process_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 124 matching lines @@
   EXPECT_GE(expected_total, free_mem2.total);
   EXPECT_GE(expected_largest, free_mem2.largest);
   EXPECT_TRUE(NULL != free_mem2.largest_ptr);
 
   delete[] alloc;
   delete metrics;
 }
 #endif  // defined(OS_WIN)
 
 #if defined(OS_POSIX)
+// Returns the maximum number of files that a process can have open.
+// Returns 0 on error.
+int GetMaxFilesOpenInProcess() {
+  struct rlimit rlim;
+  if (getrlimit(RLIMIT_NOFILE, &rlim) != 0) {
+    return 0;
+  }
+
+  // rlim_t is a uint64 - clip to maxint. We do this since FD #s are ints
+  // which are all 32 bits on the supported platforms.
+  rlim_t max_int = static_cast<rlim_t>(std::numeric_limits<int32>::max());
+  if (rlim.rlim_cur > max_int) {
+    return max_int;
+  }
+
+  return rlim.rlim_cur;
+}
+
 const int kChildPipe = 20;  // FD # for write end of pipe in child process.
 MULTIPROCESS_TEST_MAIN(ProcessUtilsLeakFDChildProcess) {
   // This child process counts the number of open FDs, it then writes that
   // number out to a pipe connected to the parent.
   int num_open_files = 0;
   int write_pipe = kChildPipe;
   int max_files = GetMaxFilesOpenInProcess();
   for (int i = STDERR_FILENO + 1; i < max_files; i++) {
     if (i != kChildPipe) {
       if (close(i) != -1) {
@@ skipping 50 matching lines @@
   EXPECT_TRUE(WaitForSingleProcess(handle, 1000));
   close(fds[0]);
   close(sockets[0]);
   close(sockets[1]);
   close(dev_null);
 }
 
 #endif  // defined(OS_POSIX)
 
 }  // namespace base