1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/toolkit/mozapps/update/updater/automounter_gonk.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,224 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim:set ts=2 sw=2 sts=2 et cindent: */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#include <android/log.h>
1.11 +#include <cutils/android_reboot.h>
1.12 +#include <errno.h>
1.13 +#include <stdlib.h>
1.14 +#include <sys/mount.h>
1.15 +#include <sys/reboot.h>
1.16 +#include <sys/types.h>
1.17 +#include <unistd.h>
1.18 +
1.19 +#include "automounter_gonk.h"
1.20 +#include "updatedefines.h"
1.21 +#include "updatelogging.h"
1.22 +
1.23 +#define LOG_TAG "GonkAutoMounter"
1.24 +
1.25 +#define GONK_LOG(level, format, ...) \
1.26 + LOG((LOG_TAG ": " format "\n", ##__VA_ARGS__)); \
1.27 + __android_log_print(level, LOG_TAG, format, ##__VA_ARGS__)
1.28 +
1.29 +#define LOGI(format, ...) GONK_LOG(ANDROID_LOG_INFO, format, ##__VA_ARGS__)
1.30 +#define LOGE(format, ...) GONK_LOG(ANDROID_LOG_ERROR, format, ##__VA_ARGS__)
1.31 +
1.32 +const char *kGonkMountsPath = "/proc/mounts";
1.33 +const char *kGonkSystemPath = "/system";
1.34 +
1.35 +GonkAutoMounter::GonkAutoMounter() : mDevice(nullptr), mAccess(Unknown)
1.36 +{
1.37 + if (!RemountSystem(ReadWrite)) {
1.38 + LOGE("Could not remount %s as read-write.", kGonkSystemPath);
1.39 + }
1.40 +}
1.41 +
1.42 +GonkAutoMounter::~GonkAutoMounter()
1.43 +{
1.44 + bool result = RemountSystem(ReadOnly);
1.45 + free(mDevice);
1.46 +
1.47 + if (!result) {
1.48 + // Don't take any chances when remounting as read-only fails, just reboot.
1.49 + Reboot();
1.50 + }
1.51 +}
1.52 +
1.53 +void
1.54 +GonkAutoMounter::Reboot()
1.55 +{
1.56 + // The android_reboot wrapper provides more safety, doing fancier read-only
1.57 + // remounting and attempting to sync() the filesystem first. If this fails
1.58 + // our only hope is to force a reboot directly without these protections.
1.59 + // For more, see system/core/libcutils/android_reboot.c
1.60 + LOGE("Could not remount %s as read-only, forcing a system reboot.",
1.61 + kGonkSystemPath);
1.62 + LogFlush();
1.63 +
1.64 + if (android_reboot(ANDROID_RB_RESTART, 0, nullptr) != 0) {
1.65 + LOGE("Safe system reboot failed, attempting to force");
1.66 + LogFlush();
1.67 +
1.68 + if (reboot(RB_AUTOBOOT) != 0) {
1.69 + LOGE("CRITICAL: Failed to force restart");
1.70 + }
1.71 + }
1.72 +}
1.73 +
1.74 +static const char *
1.75 +MountAccessToString(MountAccess access)
1.76 +{
1.77 + switch (access) {
1.78 + case ReadOnly: return "read-only";
1.79 + case ReadWrite: return "read-write";
1.80 + default: return "unknown";
1.81 + }
1.82 +}
1.83 +
1.84 +bool
1.85 +GonkAutoMounter::RemountSystem(MountAccess access)
1.86 +{
1.87 + if (!UpdateMountStatus()) {
1.88 + return false;
1.89 + }
1.90 +
1.91 + if (mAccess == access) {
1.92 + return true;
1.93 + }
1.94 +
1.95 + unsigned long flags = MS_REMOUNT;
1.96 + if (access == ReadOnly) {
1.97 + flags |= MS_RDONLY;
1.98 + // Give the system a chance to flush file buffers
1.99 + sync();
1.100 + }
1.101 +
1.102 + if (!MountSystem(flags)) {
1.103 + return false;
1.104 + }
1.105 +
1.106 + // Check status again to verify /system has been properly remounted
1.107 + if (!UpdateMountStatus()) {
1.108 + return false;
1.109 + }
1.110 +
1.111 + if (mAccess != access) {
1.112 + LOGE("Updated mount status %s should be %s",
1.113 + MountAccessToString(mAccess),
1.114 + MountAccessToString(access));
1.115 + return false;
1.116 + }
1.117 +
1.118 + return true;
1.119 +}
1.120 +
1.121 +bool
1.122 +GonkAutoMounter::UpdateMountStatus()
1.123 +{
1.124 + FILE *mountsFile = NS_tfopen(kGonkMountsPath, "r");
1.125 +
1.126 + if (mountsFile == nullptr) {
1.127 + LOGE("Error opening %s: %s", kGonkMountsPath, strerror(errno));
1.128 + return false;
1.129 + }
1.130 +
1.131 + // /proc/mounts returns a 0 size from fstat, so we use the same
1.132 + // pre-allocated buffer size that ADB does here
1.133 + const int mountsMaxSize = 4096;
1.134 + char mountData[mountsMaxSize];
1.135 + size_t read = fread(mountData, 1, mountsMaxSize - 1, mountsFile);
1.136 + mountData[read + 1] = '\0';
1.137 +
1.138 + if (ferror(mountsFile)) {
1.139 + LOGE("Error reading %s, %s", kGonkMountsPath, strerror(errno));
1.140 + fclose(mountsFile);
1.141 + return false;
1.142 + }
1.143 +
1.144 + char *token, *tokenContext;
1.145 + bool foundSystem = false;
1.146 +
1.147 + for (token = strtok_r(mountData, "\n", &tokenContext);
1.148 + token;
1.149 + token = strtok_r(nullptr, "\n", &tokenContext))
1.150 + {
1.151 + if (ProcessMount(token)) {
1.152 + foundSystem = true;
1.153 + break;
1.154 + }
1.155 + }
1.156 +
1.157 + fclose(mountsFile);
1.158 +
1.159 + if (!foundSystem) {
1.160 + LOGE("Couldn't find %s mount in %s", kGonkSystemPath, kGonkMountsPath);
1.161 + }
1.162 + return foundSystem;
1.163 +}
1.164 +
1.165 +bool
1.166 +GonkAutoMounter::ProcessMount(const char *mount)
1.167 +{
1.168 + const int strSize = 256;
1.169 + char mountDev[strSize];
1.170 + char mountDir[strSize];
1.171 + char mountAccess[strSize];
1.172 +
1.173 + int rv = sscanf(mount, "%255s %255s %*s %255s %*d %*d\n",
1.174 + mountDev, mountDir, mountAccess);
1.175 + mountDev[strSize - 1] = '\0';
1.176 + mountDir[strSize - 1] = '\0';
1.177 + mountAccess[strSize - 1] = '\0';
1.178 +
1.179 + if (rv != 3) {
1.180 + return false;
1.181 + }
1.182 +
1.183 + if (strcmp(kGonkSystemPath, mountDir) != 0) {
1.184 + return false;
1.185 + }
1.186 +
1.187 + free(mDevice);
1.188 + mDevice = strdup(mountDev);
1.189 + mAccess = Unknown;
1.190 +
1.191 + char *option, *optionContext;
1.192 + for (option = strtok_r(mountAccess, ",", &optionContext);
1.193 + option;
1.194 + option = strtok_r(nullptr, ",", &optionContext))
1.195 + {
1.196 + if (strcmp("ro", option) == 0) {
1.197 + mAccess = ReadOnly;
1.198 + break;
1.199 + } else if (strcmp("rw", option) == 0) {
1.200 + mAccess = ReadWrite;
1.201 + break;
1.202 + }
1.203 + }
1.204 +
1.205 + return true;
1.206 +}
1.207 +
1.208 +bool
1.209 +GonkAutoMounter::MountSystem(unsigned long flags)
1.210 +{
1.211 + if (!mDevice) {
1.212 + LOGE("No device was found for %s", kGonkSystemPath);
1.213 + return false;
1.214 + }
1.215 +
1.216 + const char *readOnly = flags & MS_RDONLY ? "read-only" : "read-write";
1.217 + int result = mount(mDevice, kGonkSystemPath, "none", flags, nullptr);
1.218 +
1.219 + if (result != 0) {
1.220 + LOGE("Error mounting %s as %s: %s", kGonkSystemPath, readOnly,
1.221 + strerror(errno));
1.222 + return false;
1.223 + }
1.224 +
1.225 + LOGI("Mounted %s partition as %s", kGonkSystemPath, readOnly);
1.226 + return true;
1.227 +}
