Linux: Correctly count the number of open file descriptors.

base/process/process_metrics_linux.cc

 // Copyright (c) 2013 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 "base/process/process_metrics.h"
 
 #include <dirent.h>
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <utility>
 
+#include "base/files/dir_reader_posix.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/process/internal_linux.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_tokenizer.h"
 #include "base/strings/string_util.h"
 #include "base/sys_info.h"
 #include "base/threading/thread_restrictions.h"
 
@@ skipping 259 matching lines @@
     DCHECK(converted);
   }
   return true;
 }
 
 #if defined(OS_LINUX)
 int ProcessMetrics::GetOpenFdCount() const {
   // Use /proc/<pid>/fd to count the number of entries there.
   FilePath fd_path = internal::GetProcPidDir(process_).Append("fd");
 
-  DIR* dir = opendir(fd_path.value().c_str());
-  if (!dir) {
-    DPLOG(ERROR) << "opendir(" << fd_path.value() << ")";
+  DirReaderPosix dir_reader(fd_path.value().c_str());
+  if (!dir_reader.IsValid())
     return -1;
-  }
 
   int total_count = 0;
-  while (readdir(dir))
-    ++total_count;
-
-  closedir(dir);
+  for (; dir_reader.Next(); ) {
+    const char* name = dir_reader.name();
+    if (strcmp(name, ".") != 0 && strcmp(name, "..") != 0)
+      ++total_count;
+  }
 
   return total_count;
 }
 #endif  // defined(OS_LINUX)
 
 ProcessMetrics::ProcessMetrics(ProcessHandle process)
     : process_(process),
       last_system_time_(0),
 #if defined(OS_LINUX)
       last_absolute_idle_wakeups_(0),
@@ skipping 622 matching lines @@
 #if defined(OS_LINUX)
 int ProcessMetrics::GetIdleWakeupsPerSecond() {
   uint64 wake_ups;
   const char kWakeupStat[] = "se.statistics.nr_wakeups";
   return ReadProcSchedAndGetFieldAsUint64(process_, kWakeupStat, &wake_ups) ?
       CalculateIdleWakeupsPerSecond(wake_ups) : 0;
 }
 #endif  // defined(OS_LINUX)
 
 }  // namespace base