POSIX: don't allocate memory after forking.
Previously we would allocate memory in the child process. However, the
allocation might have happened while the malloc lock was held,
resulting in a deadlock.
This patch removes allocation from the child but probably makes Mac's
startup time slower until a Mac person can implement
dir_reader_posix.h.
TEST=Unittest for new code
BUG=36678
http://codereview.chromium.org/672003
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@41275 0039d316-1c4b-4281-b951-d872f2087c98
CrOS-Libchrome-Original-Commit: ef73044e42948214832dd11dd3326b738f816eb6
diff --git a/base/dir_reader_linux.h b/base/dir_reader_linux.h
new file mode 100644
index 0000000..7fd534f
--- /dev/null
+++ b/base/dir_reader_linux.h
@@ -0,0 +1,97 @@
+// Copyright (c) 2010 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.
+
+#ifndef BASE_DIR_READER_LINUX_H_
+#define BASE_DIR_READER_LINUX_H_
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include "base/logging.h"
+#include "base/eintr_wrapper.h"
+
+// See the comments in dir_reader_posix.h about this.
+
+namespace base {
+
+struct linux_dirent {
+ uint64_t d_ino;
+ int64_t d_off;
+ unsigned short d_reclen;
+ unsigned char d_type;
+ char d_name[0];
+};
+
+class DirReaderLinux {
+ public:
+ explicit DirReaderLinux(const char* directory_path)
+ : fd_(open(directory_path, O_RDONLY | O_DIRECTORY)),
+ offset_(0),
+ size_(0) {
+ }
+
+ ~DirReaderLinux() {
+ if (fd_ >= 0) {
+ if (HANDLE_EINTR(close(fd_)))
+ RAW_LOG(ERROR, "Failed to close directory handle");
+ }
+ }
+
+ bool IsValid() const {
+ return fd_ >= 0;
+ }
+
+ // Move to the next entry returning false if the iteration is complete.
+ bool Next() {
+ if (size_) {
+ linux_dirent* dirent = reinterpret_cast<linux_dirent*>(&buf_[offset_]);
+ offset_ += dirent->d_reclen;
+ }
+
+ if (offset_ != size_)
+ return true;
+
+ const int r = syscall(__NR_getdents64, fd_, buf_, sizeof(buf_));
+ if (r == 0)
+ return false;
+ if (r == -1) {
+ DPLOG(FATAL) << "getdents64 returned an error: " << errno;
+ return false;
+ }
+ size_ = r;
+ offset_ = 0;
+ return true;
+ }
+
+ const char* name() const {
+ if (!size_)
+ return NULL;
+
+ const linux_dirent* dirent =
+ reinterpret_cast<const linux_dirent*>(&buf_[offset_]);
+ return dirent->d_name;
+ }
+
+ int fd() const {
+ return fd_;
+ }
+
+ static bool IsFallback() {
+ return false;
+ }
+
+ private:
+ const int fd_;
+ unsigned char buf_[512];
+ size_t offset_, size_;
+
+ DISALLOW_COPY_AND_ASSIGN(DirReaderLinux);
+};
+
+} // namespace base
+
+#endif // BASE_DIR_READER_LINUX_H_