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

--1:000000000000
+:1cb73e32b337
+/* -*- 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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comparison: toolkit/mozapps/update/updater/automounter_gonk.cpp

toolkit/mozapps/update/updater/automounter_gonk.cpp