chrome/browser/storage_monitor/mtab_watcher_linux.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // MtabWatcherLinux implementation.
   6
   7 #include "chrome/browser/storage_monitor/mtab_watcher_linux.h"
   8
   9 #include <mntent.h>
  10 #include <stdio.h>
  11
  12 #include "base/bind.h"
  13 #include "content/public/browser/browser_thread.h"
  14
  15 namespace {
  16
  17 // List of file systems we care about.
  18 const char* const kKnownFileSystems[] = {
  19   "ext2",
  20   "ext3",
  21   "ext4",
  22   "fat",
  23   "hfsplus",
  24   "iso9660",
  25   "msdos",
  26   "ntfs",
  27   "udf",
  28   "vfat",
  29 };
  30
  31 }  // namespace
  32
  33 MtabWatcherLinux::MtabWatcherLinux(const base::FilePath& mtab_path,
  34                                    base::WeakPtr<Delegate> delegate)
  35     : mtab_path_(mtab_path),
  36       delegate_(delegate),
  37       weak_ptr_factory_(this) {
  38   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
  39   bool ret = file_watcher_.Watch(
  40       mtab_path_, false,
  41       base::Bind(&MtabWatcherLinux::OnFilePathChanged,
  42                  weak_ptr_factory_.GetWeakPtr()));
  43   if (!ret) {
  44     LOG(ERROR) << "Adding watch for " << mtab_path_.value() << " failed";
  45     return;
  46   }
  47
  48   ReadMtab();
  49 }
  50
  51 MtabWatcherLinux::~MtabWatcherLinux() {
  52   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
  53 }
  54
  55 void MtabWatcherLinux::ReadMtab() const {
  56   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
  57
  58   FILE* fp = setmntent(mtab_path_.value().c_str(), "r");
  59   if (!fp)
  60     return;
  61
  62   MountPointDeviceMap device_map;
  63   mntent entry;
  64   char buf[512];
  65
  66   // We return the same device mounted to multiple locations, but hide
  67   // devices that have been mounted over.
  68   while (getmntent_r(fp, &entry, buf, sizeof(buf))) {
  69     // We only care about real file systems.
  70     for (size_t i = 0; i < arraysize(kKnownFileSystems); ++i) {
  71       if (strcmp(kKnownFileSystems[i], entry.mnt_type) == 0) {
  72         device_map[base::FilePath(entry.mnt_dir)] =
  73             base::FilePath(entry.mnt_fsname);
  74         break;
  75       }
  76     }
  77   }
  78   endmntent(fp);
  79
  80   content::BrowserThread::PostTask(
  81       content::BrowserThread::UI, FROM_HERE,
  82       base::Bind(&Delegate::UpdateMtab, delegate_, device_map));
  83 }
  84
  85 void MtabWatcherLinux::OnFilePathChanged(
  86     const base::FilePath& path, bool error) {
  87   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
  88
  89   if (path != mtab_path_) {
  90     // This cannot happen unless FilePathWatcher is buggy. Just ignore this
  91     // notification and do nothing.
  92     NOTREACHED();
  93     return;
  94   }
  95   if (error) {
  96     LOG(ERROR) << "Error watching " << mtab_path_.value();
  97     return;
  98   }
  99
 100   ReadMtab();
 101 }