tor-browser

The Tor Browser
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dir_reader_linux.h (2179B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
      4 // Use of this source code is governed by a BSD-style license that can be
      5 // found in the LICENSE file.
      6 
      7 #ifndef BASE_DIR_READER_LINUX_H_
      8 #define BASE_DIR_READER_LINUX_H_
      9 #pragma once
     10 
     11 #include <errno.h>
     12 #include <fcntl.h>
     13 #include <stdint.h>
     14 #include <sys/syscall.h>
     15 #include <unistd.h>
     16 
     17 #include "base/logging.h"
     18 #include "base/eintr_wrapper.h"
     19 
     20 // See the comments in dir_reader_posix.h about this.
     21 
     22 namespace base {
     23 
     24 struct linux_dirent {
     25  uint64_t d_ino;
     26  int64_t d_off;
     27  unsigned short d_reclen;
     28  unsigned char d_type;
     29  char d_name[0];
     30 };
     31 
     32 class DirReaderLinux {
     33 public:
     34  explicit DirReaderLinux(const char* directory_path)
     35      : fd_(open(directory_path, O_RDONLY | O_DIRECTORY)),
     36        offset_(0),
     37        size_(0) {
     38    memset(buf_, 0, sizeof(buf_));
     39  }
     40 
     41  ~DirReaderLinux() {
     42    if (fd_ >= 0) {
     43      if (IGNORE_EINTR(close(fd_)))
     44        DLOG(ERROR) << "Failed to close directory handle";
     45    }
     46  }
     47 
     48  bool IsValid() const { return fd_ >= 0; }
     49 
     50  // Move to the next entry returning false if the iteration is complete.
     51  bool Next() {
     52    if (size_) {
     53      linux_dirent* dirent = reinterpret_cast<linux_dirent*>(&buf_[offset_]);
     54      offset_ += dirent->d_reclen;
     55    }
     56 
     57    if (offset_ != size_) return true;
     58 
     59    const int r = syscall(__NR_getdents64, fd_, buf_, sizeof(buf_));
     60    if (r == 0) return false;
     61    if (r == -1) {
     62      DLOG(ERROR) << "getdents64 returned an error: " << errno;
     63      return false;
     64    }
     65    size_ = r;
     66    offset_ = 0;
     67    return true;
     68  }
     69 
     70  const char* name() const {
     71    if (!size_) return NULL;
     72 
     73    const linux_dirent* dirent =
     74        reinterpret_cast<const linux_dirent*>(&buf_[offset_]);
     75    return dirent->d_name;
     76  }
     77 
     78  int fd() const { return fd_; }
     79 
     80  static bool IsFallback() { return false; }
     81 
     82 private:
     83  const int fd_;
     84  union {
     85    linux_dirent dirent_;
     86    unsigned char buf_[512];
     87  };
     88  size_t offset_, size_;
     89 
     90  DISALLOW_COPY_AND_ASSIGN(DirReaderLinux);
     91 };
     92 
     93 }  // namespace base
     94 
     95 #endif  // BASE_DIR_READER_LINUX_H_