The Tor Browser: toolkit/mozapps/update/updater/automounter

toolkit/mozapps/update/updater/automounter_gonk.cpp@6474c204b198 (annotated)

toolkit/mozapps/update/updater/automounter_gonk.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim:set ts=2 sw=2 sts=2 et cindent: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include <android/log.h>
 #include <cutils/android_reboot.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <sys/mount.h>
 #include <sys/reboot.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include "automounter_gonk.h"
 #include "updatedefines.h"
 #include "updatelogging.h"
 #define LOG_TAG "GonkAutoMounter"
 #define GONK_LOG(level, format, ...) \
   LOG((LOG_TAG ": " format "\n", ##__VA_ARGS__)); \
   __android_log_print(level, LOG_TAG, format, ##__VA_ARGS__)
 #define LOGI(format, ...) GONK_LOG(ANDROID_LOG_INFO, format, ##__VA_ARGS__)
 #define LOGE(format, ...) GONK_LOG(ANDROID_LOG_ERROR, format, ##__VA_ARGS__)
 const char *kGonkMountsPath = "/proc/mounts";
 const char *kGonkSystemPath = "/system";
 GonkAutoMounter::GonkAutoMounter() : mDevice(nullptr), mAccess(Unknown)
 {
   if (!RemountSystem(ReadWrite)) {
     LOGE("Could not remount %s as read-write.", kGonkSystemPath);
   }
 }
 GonkAutoMounter::~GonkAutoMounter()
 {
   bool result = RemountSystem(ReadOnly);
   free(mDevice);
   if (!result) {
     // Don't take any chances when remounting as read-only fails, just reboot.
     Reboot();
   }
 }
 void
 GonkAutoMounter::Reboot()
 {
   // The android_reboot wrapper provides more safety, doing fancier read-only
   // remounting and attempting to sync() the filesystem first. If this fails
   // our only hope is to force a reboot directly without these protections.
   // For more, see system/core/libcutils/android_reboot.c
   LOGE("Could not remount %s as read-only, forcing a system reboot.",
        kGonkSystemPath);
   LogFlush();
   if (android_reboot(ANDROID_RB_RESTART, 0, nullptr) != 0) {
     LOGE("Safe system reboot failed, attempting to force");
     LogFlush();
     if (reboot(RB_AUTOBOOT) != 0) {
       LOGE("CRITICAL: Failed to force restart");
     }
   }
 }
 static const char *
 MountAccessToString(MountAccess access)
 {
   switch (access) {
     case ReadOnly: return "read-only";
     case ReadWrite: return "read-write";
     default: return "unknown";
   }
 }
 bool
 GonkAutoMounter::RemountSystem(MountAccess access)
 {
   if (!UpdateMountStatus()) {
     return false;
   }
   if (mAccess == access) {
     return true;
   }
   unsigned long flags = MS_REMOUNT;
   if (access == ReadOnly) {
     flags |= MS_RDONLY;
     // Give the system a chance to flush file buffers
     sync();
   }
   if (!MountSystem(flags)) {
     return false;
   }
   // Check status again to verify /system has been properly remounted
   if (!UpdateMountStatus()) {
     return false;
   }
   if (mAccess != access) {
     LOGE("Updated mount status %s should be %s",
          MountAccessToString(mAccess),
          MountAccessToString(access));
     return false;
   }
   return true;
 }
 bool
 GonkAutoMounter::UpdateMountStatus()
 {
   FILE *mountsFile = NS_tfopen(kGonkMountsPath, "r");
   if (mountsFile == nullptr) {
     LOGE("Error opening %s: %s", kGonkMountsPath, strerror(errno));
     return false;
   }
   // /proc/mounts returns a 0 size from fstat, so we use the same
   // pre-allocated buffer size that ADB does here
   const int mountsMaxSize = 4096;
   char mountData[mountsMaxSize];
   size_t read = fread(mountData, 1, mountsMaxSize - 1, mountsFile);
   mountData[read + 1] = '\0';
   if (ferror(mountsFile)) {
     LOGE("Error reading %s, %s", kGonkMountsPath, strerror(errno));
     fclose(mountsFile);
     return false;
   }
   char *token, *tokenContext;
   bool foundSystem = false;
   for (token = strtok_r(mountData, "\n", &tokenContext);
        token;
        token = strtok_r(nullptr, "\n", &tokenContext))
   {
     if (ProcessMount(token)) {
       foundSystem = true;
       break;
     }
   }
   fclose(mountsFile);
   if (!foundSystem) {
     LOGE("Couldn't find %s mount in %s", kGonkSystemPath, kGonkMountsPath);
   }
   return foundSystem;
 }
 bool
 GonkAutoMounter::ProcessMount(const char *mount)
 {
   const int strSize = 256;
   char mountDev[strSize];
   char mountDir[strSize];
   char mountAccess[strSize];
   int rv = sscanf(mount, "%255s %255s %*s %255s %*d %*d\n",
                   mountDev, mountDir, mountAccess);
   mountDev[strSize - 1] = '\0';
   mountDir[strSize - 1] = '\0';
   mountAccess[strSize - 1] = '\0';
   if (rv != 3) {
     return false;
   }
   if (strcmp(kGonkSystemPath, mountDir) != 0) {
     return false;
   }
   free(mDevice);
   mDevice = strdup(mountDev);
   mAccess = Unknown;
   char *option, *optionContext;
   for (option = strtok_r(mountAccess, ",", &optionContext);
        option;
        option = strtok_r(nullptr, ",", &optionContext))
   {
     if (strcmp("ro", option) == 0) {
       mAccess = ReadOnly;
       break;
     } else if (strcmp("rw", option) == 0) {
       mAccess = ReadWrite;
       break;
     }
   }
   return true;
 }
 bool
 GonkAutoMounter::MountSystem(unsigned long flags)
 {
   if (!mDevice) {
     LOGE("No device was found for %s", kGonkSystemPath);
     return false;
   }
   const char *readOnly = flags & MS_RDONLY ? "read-only" : "read-write";
   int result = mount(mDevice, kGonkSystemPath, "none", flags, nullptr);
   if (result != 0) {
     LOGE("Error mounting %s as %s: %s", kGonkSystemPath, readOnly,
          strerror(errno));
     return false;
   }
   LOGI("Mounted %s partition as %s", kGonkSystemPath, readOnly);
   return true;
 }

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toolkit/mozapps/update/updater/automounter_gonk.cpp@6474c204b198 (annotated)

toolkit/mozapps/update/updater/automounter_gonk.cpp