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platform_system_core/init/reboot.cpp
Keun-young Park 6e12b3887e Do not umount /vendor, /system, and /oem even if they are R/W. 
- /vendor, /system, /oem can be remounted to R/W for development
  purpose.

- In such case, umounting these partitions can lead into some processes
  not running properly during shutdown or blocking umount of fs.

- So skip them. As it is dev feature, it is up to each developer to
  understand the risk. But for normal adb sync - reboot should be ok
  as shutdown involves sync operations.

bug: 37737296
Test: adb remount,reboot, and check last kmsg
Change-Id: Iab6a6374bc558375d359b3b49b14db93d363b1ad
2017-07-17 17:32:26 -07:00

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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "reboot.h"
#include <dirent.h>
#include <fcntl.h>
#include <linux/fs.h>
#include <mntent.h>
#include <sys/capability.h>
#include <sys/cdefs.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/reboot.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <memory>
#include <set>
#include <thread>
#include <vector>
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/macros.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <bootloader_message/bootloader_message.h>
#include <cutils/android_reboot.h>
#include <fs_mgr.h>
#include <logwrap/logwrap.h>
#include <private/android_filesystem_config.h>
#include "capabilities.h"
#include "init.h"
#include "property_service.h"
#include "service.h"
using android::base::StringPrintf;
using android::base::Timer;
namespace android {
namespace init {
// represents umount status during reboot / shutdown.
enum UmountStat {
/* umount succeeded. */
UMOUNT_STAT_SUCCESS = 0,
/* umount was not run. */
UMOUNT_STAT_SKIPPED = 1,
/* umount failed with timeout. */
UMOUNT_STAT_TIMEOUT = 2,
/* could not run due to error */
UMOUNT_STAT_ERROR = 3,
/* not used by init but reserved for other part to use this to represent the
the state where umount status before reboot is not found / available. */
UMOUNT_STAT_NOT_AVAILABLE = 4,
};
// Utility for struct mntent
class MountEntry {
public:
explicit MountEntry(const mntent& entry)
: mnt_fsname_(entry.mnt_fsname),
mnt_dir_(entry.mnt_dir),
mnt_type_(entry.mnt_type),
mnt_opts_(entry.mnt_opts) {}
bool Umount() {
int r = umount2(mnt_dir_.c_str(), 0);
if (r == 0) {
LOG(INFO) << "umounted " << mnt_fsname_ << ":" << mnt_dir_ << " opts " << mnt_opts_;
return true;
} else {
PLOG(WARNING) << "cannot umount " << mnt_fsname_ << ":" << mnt_dir_ << " opts "
<< mnt_opts_;
return false;
}
}
void DoFsck() {
int st;
if (IsF2Fs()) {
const char* f2fs_argv[] = {
"/system/bin/fsck.f2fs", "-f", mnt_fsname_.c_str(),
};
android_fork_execvp_ext(arraysize(f2fs_argv), (char**)f2fs_argv, &st, true, LOG_KLOG,
true, nullptr, nullptr, 0);
} else if (IsExt4()) {
const char* ext4_argv[] = {
"/system/bin/e2fsck", "-f", "-y", mnt_fsname_.c_str(),
};
android_fork_execvp_ext(arraysize(ext4_argv), (char**)ext4_argv, &st, true, LOG_KLOG,
true, nullptr, nullptr, 0);
}
}
static bool IsBlockDevice(const struct mntent& mntent) {
return android::base::StartsWith(mntent.mnt_fsname, "/dev/block");
}
static bool IsEmulatedDevice(const struct mntent& mntent) {
return android::base::StartsWith(mntent.mnt_fsname, "/data/");
}
private:
bool IsF2Fs() const { return mnt_type_ == "f2fs"; }
bool IsExt4() const { return mnt_type_ == "ext4"; }
std::string mnt_fsname_;
std::string mnt_dir_;
std::string mnt_type_;
std::string mnt_opts_;
};
// Turn off backlight while we are performing power down cleanup activities.
static void TurnOffBacklight() {
static constexpr char OFF[] = "0";
android::base::WriteStringToFile(OFF, "/sys/class/leds/lcd-backlight/brightness");
static const char backlightDir[] = "/sys/class/backlight";
std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(backlightDir), closedir);
if (!dir) {
return;
}
struct dirent* dp;
while ((dp = readdir(dir.get())) != nullptr) {
if (((dp->d_type != DT_DIR) && (dp->d_type != DT_LNK)) || (dp->d_name[0] == '.')) {
continue;
}
std::string fileName = StringPrintf("%s/%s/brightness", backlightDir, dp->d_name);
android::base::WriteStringToFile(OFF, fileName);
}
}
static void ShutdownVold() {
const char* vdc_argv[] = {"/system/bin/vdc", "volume", "shutdown"};
int status;
android_fork_execvp_ext(arraysize(vdc_argv), (char**)vdc_argv, &status, true, LOG_KLOG, true,
nullptr, nullptr, 0);
}
static void LogShutdownTime(UmountStat stat, Timer* t) {
LOG(WARNING) << "powerctl_shutdown_time_ms:" << std::to_string(t->duration().count()) << ":"
<< stat;
}
// Determines whether the system is capable of rebooting. This is conservative,
// so if any of the attempts to determine this fail, it will still return true.
static bool IsRebootCapable() {
if (!CAP_IS_SUPPORTED(CAP_SYS_BOOT)) {
PLOG(WARNING) << "CAP_SYS_BOOT is not supported";
return true;
}
ScopedCaps caps(cap_get_proc());
if (!caps) {
PLOG(WARNING) << "cap_get_proc() failed";
return true;
}
cap_flag_value_t value = CAP_SET;
if (cap_get_flag(caps.get(), CAP_SYS_BOOT, CAP_EFFECTIVE, &value) != 0) {
PLOG(WARNING) << "cap_get_flag(CAP_SYS_BOOT, EFFECTIVE) failed";
return true;
}
return value == CAP_SET;
}
static void __attribute__((noreturn))
RebootSystem(unsigned int cmd, const std::string& rebootTarget) {
LOG(INFO) << "Reboot ending, jumping to kernel";
if (!IsRebootCapable()) {
// On systems where init does not have the capability of rebooting the
// device, just exit cleanly.
exit(0);
}
switch (cmd) {
case ANDROID_RB_POWEROFF:
reboot(RB_POWER_OFF);
break;
case ANDROID_RB_RESTART2:
syscall(__NR_reboot, LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2,
LINUX_REBOOT_CMD_RESTART2, rebootTarget.c_str());
break;
case ANDROID_RB_THERMOFF:
reboot(RB_POWER_OFF);
break;
}
// In normal case, reboot should not return.
PLOG(FATAL) << "reboot call returned";
abort();
}
/* Find all read+write block devices and emulated devices in /proc/mounts
* and add them to correpsponding list.
*/
static bool FindPartitionsToUmount(std::vector<MountEntry>* blockDevPartitions,
std::vector<MountEntry>* emulatedPartitions, bool dump) {
std::unique_ptr<std::FILE, int (*)(std::FILE*)> fp(setmntent("/proc/mounts", "r"), endmntent);
if (fp == nullptr) {
PLOG(ERROR) << "Failed to open /proc/mounts";
return false;
}
mntent* mentry;
while ((mentry = getmntent(fp.get())) != nullptr) {
if (dump) {
LOG(INFO) << "mount entry " << mentry->mnt_fsname << ":" << mentry->mnt_dir << " opts "
<< mentry->mnt_opts << " type " << mentry->mnt_type;
} else if (MountEntry::IsBlockDevice(*mentry) && hasmntopt(mentry, "rw")) {
std::string mount_dir(mentry->mnt_dir);
// These are R/O partitions changed to R/W after adb remount.
// Do not umount them as shutdown critical services may rely on them.
if (mount_dir != "/system" && mount_dir != "/vendor" && mount_dir != "/oem") {
blockDevPartitions->emplace(blockDevPartitions->begin(), *mentry);
}
} else if (MountEntry::IsEmulatedDevice(*mentry)) {
emulatedPartitions->emplace(emulatedPartitions->begin(), *mentry);
}
}
return true;
}
static void DumpUmountDebuggingInfo(bool dump_all) {
int status;
if (!security_getenforce()) {
LOG(INFO) << "Run lsof";
const char* lsof_argv[] = {"/system/bin/lsof"};
android_fork_execvp_ext(arraysize(lsof_argv), (char**)lsof_argv, &status, true, LOG_KLOG,
true, nullptr, nullptr, 0);
}
FindPartitionsToUmount(nullptr, nullptr, true);
if (dump_all) {
// dump current tasks, this log can be lengthy, so only dump with dump_all
android::base::WriteStringToFile("t", "/proc/sysrq-trigger");
}
}
static UmountStat UmountPartitions(std::chrono::milliseconds timeout) {
Timer t;
UmountStat stat = UMOUNT_STAT_TIMEOUT;
int retry = 0;
/* data partition needs all pending writes to be completed and all emulated partitions
* umounted.If the current waiting is not good enough, give
* up and leave it to e2fsck after reboot to fix it.
*/
while (true) {
std::vector<MountEntry> block_devices;
std::vector<MountEntry> emulated_devices;
if (!FindPartitionsToUmount(&block_devices, &emulated_devices, false)) {
return UMOUNT_STAT_ERROR;
}
if (block_devices.size() == 0) {
stat = UMOUNT_STAT_SUCCESS;
break;
}
if ((timeout < t.duration()) && retry > 0) { // try umount at least once
stat = UMOUNT_STAT_TIMEOUT;
break;
}
if (emulated_devices.size() > 0 &&
std::all_of(emulated_devices.begin(), emulated_devices.end(),
[](auto& entry) { return entry.Umount(); })) {
sync();
}
for (auto& entry : block_devices) {
entry.Umount();
}
retry++;
std::this_thread::sleep_for(100ms);
}
return stat;
}
static void KillAllProcesses() { android::base::WriteStringToFile("i", "/proc/sysrq-trigger"); }
/* Try umounting all emulated file systems R/W block device cfile systems.
* This will just try umount and give it up if it fails.
* For fs like ext4, this is ok as file system will be marked as unclean shutdown
* and necessary check can be done at the next reboot.
* For safer shutdown, caller needs to make sure that
* all processes / emulated partition for the target fs are all cleaned-up.
*
* return true when umount was successful. false when timed out.
*/
static UmountStat TryUmountAndFsck(bool runFsck, std::chrono::milliseconds timeout) {
Timer t;
std::vector<MountEntry> block_devices;
std::vector<MountEntry> emulated_devices;
TurnOffBacklight(); // this part can take time. save power.
if (runFsck && !FindPartitionsToUmount(&block_devices, &emulated_devices, false)) {
return UMOUNT_STAT_ERROR;
}
UmountStat stat = UmountPartitions(timeout - t.duration());
if (stat != UMOUNT_STAT_SUCCESS) {
LOG(INFO) << "umount timeout, last resort, kill all and try";
if (DUMP_ON_UMOUNT_FAILURE) DumpUmountDebuggingInfo(false);
KillAllProcesses();
// even if it succeeds, still it is timeout and do not run fsck with all processes killed
UmountPartitions(0ms);
if (DUMP_ON_UMOUNT_FAILURE) DumpUmountDebuggingInfo(true);
}
if (stat == UMOUNT_STAT_SUCCESS && runFsck) {
// fsck part is excluded from timeout check. It only runs for user initiated shutdown
// and should not affect reboot time.
for (auto& entry : block_devices) {
entry.DoFsck();
}
}
return stat;
}
static void __attribute__((noreturn)) DoThermalOff() {
LOG(WARNING) << "Thermal system shutdown";
sync();
RebootSystem(ANDROID_RB_THERMOFF, "");
abort();
}
void DoReboot(unsigned int cmd, const std::string& reason, const std::string& rebootTarget,
bool runFsck) {
Timer t;
LOG(INFO) << "Reboot start, reason: " << reason << ", rebootTarget: " << rebootTarget;
android::base::WriteStringToFile(StringPrintf("%s\n", reason.c_str()), LAST_REBOOT_REASON_FILE,
S_IRUSR | S_IWUSR, AID_SYSTEM, AID_SYSTEM);
if (cmd == ANDROID_RB_THERMOFF) { // do not wait if it is thermal
DoThermalOff();
abort();
}
auto shutdown_timeout = 0s;
if (!SHUTDOWN_ZERO_TIMEOUT) {
constexpr unsigned int shutdown_timeout_default = 6;
auto shutdown_timeout_property =
android::base::GetUintProperty("ro.build.shutdown_timeout", shutdown_timeout_default);
shutdown_timeout = std::chrono::seconds(shutdown_timeout_property);
}
LOG(INFO) << "Shutdown timeout: " << shutdown_timeout.count() << " seconds";
// keep debugging tools until non critical ones are all gone.
const std::set<std::string> kill_after_apps{"tombstoned", "logd", "adbd"};
// watchdogd is a vendor specific component but should be alive to complete shutdown safely.
const std::set<std::string> to_starts{"watchdogd"};
ServiceManager::GetInstance().ForEachService([&kill_after_apps, &to_starts](Service* s) {
if (kill_after_apps.count(s->name())) {
s->SetShutdownCritical();
} else if (to_starts.count(s->name())) {
s->Start();
s->SetShutdownCritical();
} else if (s->IsShutdownCritical()) {
s->Start(); // start shutdown critical service if not started
}
});
Service* bootAnim = ServiceManager::GetInstance().FindServiceByName("bootanim");
Service* surfaceFlinger = ServiceManager::GetInstance().FindServiceByName("surfaceflinger");
if (bootAnim != nullptr && surfaceFlinger != nullptr && surfaceFlinger->IsRunning()) {
ServiceManager::GetInstance().ForEachServiceInClass("animation", [](Service* s) {
s->SetShutdownCritical(); // will not check animation class separately
});
}
// optional shutdown step
// 1. terminate all services except shutdown critical ones. wait for delay to finish
if (shutdown_timeout > 0s) {
LOG(INFO) << "terminating init services";
// Ask all services to terminate except shutdown critical ones.
ServiceManager::GetInstance().ForEachService([](Service* s) {
if (!s->IsShutdownCritical()) s->Terminate();
});
int service_count = 0;
// Up to half as long as shutdown_timeout or 3 seconds, whichever is lower.
auto termination_wait_timeout = std::min((shutdown_timeout + 1s) / 2, 3s);
while (t.duration() < termination_wait_timeout) {
ServiceManager::GetInstance().ReapAnyOutstandingChildren();
service_count = 0;
ServiceManager::GetInstance().ForEachService([&service_count](Service* s) {
// Count the number of services running except shutdown critical.
// Exclude the console as it will ignore the SIGTERM signal
// and not exit.
// Note: SVC_CONSOLE actually means "requires console" but
// it is only used by the shell.
if (!s->IsShutdownCritical() && s->pid() != 0 && (s->flags() & SVC_CONSOLE) == 0) {
service_count++;
}
});
if (service_count == 0) {
// All terminable services terminated. We can exit early.
break;
}
// Wait a bit before recounting the number or running services.
std::this_thread::sleep_for(50ms);
}
LOG(INFO) << "Terminating running services took " << t
<< " with remaining services:" << service_count;
}
// minimum safety steps before restarting
// 2. kill all services except ones that are necessary for the shutdown sequence.
ServiceManager::GetInstance().ForEachService([](Service* s) {
if (!s->IsShutdownCritical()) s->Stop();
});
ServiceManager::GetInstance().ReapAnyOutstandingChildren();
// 3. send volume shutdown to vold
Service* voldService = ServiceManager::GetInstance().FindServiceByName("vold");
if (voldService != nullptr && voldService->IsRunning()) {
ShutdownVold();
voldService->Stop();
} else {
LOG(INFO) << "vold not running, skipping vold shutdown";
}
// logcat stopped here
ServiceManager::GetInstance().ForEachService([&kill_after_apps](Service* s) {
if (kill_after_apps.count(s->name())) s->Stop();
});
// 4. sync, try umount, and optionally run fsck for user shutdown
sync();
UmountStat stat = TryUmountAndFsck(runFsck, shutdown_timeout - t.duration());
// Follow what linux shutdown is doing: one more sync with little bit delay
sync();
std::this_thread::sleep_for(100ms);
LogShutdownTime(stat, &t);
// Reboot regardless of umount status. If umount fails, fsck after reboot will fix it.
RebootSystem(cmd, rebootTarget);
abort();
}
bool HandlePowerctlMessage(const std::string& command) {
unsigned int cmd = 0;
std::vector<std::string> cmd_params = android::base::Split(command, ",");
std::string reboot_target = "";
bool run_fsck = false;
bool command_invalid = false;
if (cmd_params.size() > 3) {
command_invalid = true;
} else if (cmd_params[0] == "shutdown") {
cmd = ANDROID_RB_POWEROFF;
if (cmd_params.size() == 2 && cmd_params[1] == "userrequested") {
// The shutdown reason is PowerManager.SHUTDOWN_USER_REQUESTED.
// Run fsck once the file system is remounted in read-only mode.
run_fsck = true;
}
} else if (cmd_params[0] == "reboot") {
cmd = ANDROID_RB_RESTART2;
if (cmd_params.size() >= 2) {
reboot_target = cmd_params[1];
// When rebooting to the bootloader notify the bootloader writing
// also the BCB.
if (reboot_target == "bootloader") {
std::string err;
if (!write_reboot_bootloader(&err)) {
LOG(ERROR) << "reboot-bootloader: Error writing "
"bootloader_message: "
<< err;
}
}
// If there is an additional bootloader parameter, pass it along
if (cmd_params.size() == 3) {
reboot_target += "," + cmd_params[2];
}
}
} else if (command == "thermal-shutdown") { // no additional parameter allowed
cmd = ANDROID_RB_THERMOFF;
// Do not queue "shutdown" trigger since we want to shutdown immediately
DoReboot(cmd, command, reboot_target, run_fsck);
return true;
} else {
command_invalid = true;
}
if (command_invalid) {
LOG(ERROR) << "powerctl: unrecognized command '" << command << "'";
return false;
}
LOG(INFO) << "Clear action queue and start shutdown trigger";
ActionManager::GetInstance().ClearQueue();
// Queue shutdown trigger first
ActionManager::GetInstance().QueueEventTrigger("shutdown");
// Queue built-in shutdown_done
auto shutdown_handler = [cmd, command, reboot_target,
run_fsck](const std::vector<std::string>&) {
DoReboot(cmd, command, reboot_target, run_fsck);
return 0;
};
ActionManager::GetInstance().QueueBuiltinAction(shutdown_handler, "shutdown_done");
// Skip wait for prop if it is in progress
ResetWaitForProp();
// Skip wait for exec if it is in progress
if (ServiceManager::GetInstance().IsWaitingForExec()) {
ServiceManager::GetInstance().ClearExecWait();
}
return true;
}
} // namespace init
} // namespace android
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