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platform_system_vold/VolumeManager.cpp
Eric Biggers 0d12fd668d Stop using -Wno-unused-variable 
This is a useful warning, so remove two unused variables and stop
disabling this warning.

Change-Id: I3efe0b300ea139ea11d645dec6fb2613acc0e51b
2022-03-10 20:17:23 +00:00

1180 lines
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/*
* Copyright (C) 2008 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.
*/
#define ATRACE_TAG ATRACE_TAG_PACKAGE_MANAGER
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <mntent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <array>
#include <linux/kdev_t.h>
#include <ApexProperties.sysprop.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <async_safe/log.h>
#include <cutils/fs.h>
#include <utils/Trace.h>
#include <selinux/android.h>
#include <sysutils/NetlinkEvent.h>
#include <private/android_filesystem_config.h>
#include <fscrypt/fscrypt.h>
#include "AppFuseUtil.h"
#include "FsCrypt.h"
#include "Loop.h"
#include "NetlinkManager.h"
#include "Process.h"
#include "Utils.h"
#include "VoldNativeService.h"
#include "VoldUtil.h"
#include "VolumeManager.h"
#include "fs/Ext4.h"
#include "fs/Vfat.h"
#include "model/EmulatedVolume.h"
#include "model/ObbVolume.h"
#include "model/PrivateVolume.h"
#include "model/StubVolume.h"
using android::OK;
using android::base::GetBoolProperty;
using android::base::StartsWith;
using android::base::StringAppendF;
using android::base::StringPrintf;
using android::base::unique_fd;
using android::vold::BindMount;
using android::vold::CreateDir;
using android::vold::DeleteDirContents;
using android::vold::DeleteDirContentsAndDir;
using android::vold::EnsureDirExists;
using android::vold::IsFilesystemSupported;
using android::vold::IsSdcardfsUsed;
using android::vold::IsVirtioBlkDevice;
using android::vold::PrepareAndroidDirs;
using android::vold::PrepareAppDirFromRoot;
using android::vold::PrivateVolume;
using android::vold::Symlink;
using android::vold::Unlink;
using android::vold::UnmountTree;
using android::vold::VoldNativeService;
using android::vold::VolumeBase;
static const char* kPathVirtualDisk = "/data/misc/vold/virtual_disk";
static const char* kPropVirtualDisk = "persist.sys.virtual_disk";
static const std::string kEmptyString("");
/* 512MiB is large enough for testing purposes */
static const unsigned int kSizeVirtualDisk = 536870912;
static const unsigned int kMajorBlockMmc = 179;
using ScanProcCallback = bool(*)(uid_t uid, pid_t pid, int nsFd, const char* name, void* params);
VolumeManager* VolumeManager::sInstance = NULL;
VolumeManager* VolumeManager::Instance() {
if (!sInstance) sInstance = new VolumeManager();
return sInstance;
}
VolumeManager::VolumeManager() {
mDebug = false;
mNextObbId = 0;
mNextStubId = 0;
// For security reasons, assume that a secure keyguard is
// showing until we hear otherwise
mSecureKeyguardShowing = true;
}
VolumeManager::~VolumeManager() {}
int VolumeManager::updateVirtualDisk() {
ATRACE_NAME("VolumeManager::updateVirtualDisk");
if (GetBoolProperty(kPropVirtualDisk, false)) {
if (access(kPathVirtualDisk, F_OK) != 0) {
Loop::createImageFile(kPathVirtualDisk, kSizeVirtualDisk / 512);
}
if (mVirtualDisk == nullptr) {
if (Loop::create(kPathVirtualDisk, mVirtualDiskPath) != 0) {
LOG(ERROR) << "Failed to create virtual disk";
return -1;
}
struct stat buf;
if (stat(mVirtualDiskPath.c_str(), &buf) < 0) {
PLOG(ERROR) << "Failed to stat " << mVirtualDiskPath;
return -1;
}
auto disk = new android::vold::Disk(
"virtual", buf.st_rdev, "virtual",
android::vold::Disk::Flags::kAdoptable | android::vold::Disk::Flags::kSd);
mVirtualDisk = std::shared_ptr<android::vold::Disk>(disk);
handleDiskAdded(mVirtualDisk);
}
} else {
if (mVirtualDisk != nullptr) {
dev_t device = mVirtualDisk->getDevice();
handleDiskRemoved(device);
Loop::destroyByDevice(mVirtualDiskPath.c_str());
mVirtualDisk = nullptr;
}
if (access(kPathVirtualDisk, F_OK) == 0) {
unlink(kPathVirtualDisk);
}
}
return 0;
}
int VolumeManager::setDebug(bool enable) {
mDebug = enable;
return 0;
}
int VolumeManager::start() {
ATRACE_NAME("VolumeManager::start");
// Always start from a clean slate by unmounting everything in
// directories that we own, in case we crashed.
unmountAll();
Loop::destroyAll();
// Assume that we always have an emulated volume on internal
// storage; the framework will decide if it should be mounted.
CHECK(mInternalEmulatedVolumes.empty());
auto vol = std::shared_ptr<android::vold::VolumeBase>(
new android::vold::EmulatedVolume("/data/media", 0));
vol->setMountUserId(0);
vol->create();
mInternalEmulatedVolumes.push_back(vol);
// Consider creating a virtual disk
updateVirtualDisk();
return 0;
}
void VolumeManager::handleBlockEvent(NetlinkEvent* evt) {
std::lock_guard<std::mutex> lock(mLock);
if (mDebug) {
LOG(DEBUG) << "----------------";
LOG(DEBUG) << "handleBlockEvent with action " << (int)evt->getAction();
evt->dump();
}
std::string eventPath(evt->findParam("DEVPATH") ? evt->findParam("DEVPATH") : "");
std::string devType(evt->findParam("DEVTYPE") ? evt->findParam("DEVTYPE") : "");
if (devType != "disk") return;
int major = std::stoi(evt->findParam("MAJOR"));
int minor = std::stoi(evt->findParam("MINOR"));
dev_t device = makedev(major, minor);
switch (evt->getAction()) {
case NetlinkEvent::Action::kAdd: {
for (const auto& source : mDiskSources) {
if (source->matches(eventPath)) {
// For now, assume that MMC and virtio-blk (the latter is
// specific to virtual platforms; see Utils.cpp for details)
// devices are SD, and that everything else is USB
int flags = source->getFlags();
if (major == kMajorBlockMmc || IsVirtioBlkDevice(major)) {
flags |= android::vold::Disk::Flags::kSd;
} else {
flags |= android::vold::Disk::Flags::kUsb;
}
auto disk =
new android::vold::Disk(eventPath, device, source->getNickname(), flags);
handleDiskAdded(std::shared_ptr<android::vold::Disk>(disk));
break;
}
}
break;
}
case NetlinkEvent::Action::kChange: {
LOG(VERBOSE) << "Disk at " << major << ":" << minor << " changed";
handleDiskChanged(device);
break;
}
case NetlinkEvent::Action::kRemove: {
handleDiskRemoved(device);
break;
}
default: {
LOG(WARNING) << "Unexpected block event action " << (int)evt->getAction();
break;
}
}
}
void VolumeManager::handleDiskAdded(const std::shared_ptr<android::vold::Disk>& disk) {
// For security reasons, if secure keyguard is showing, wait
// until the user unlocks the device to actually touch it
// Additionally, wait until user 0 is actually started, since we need
// the user to be up before we can mount a FUSE daemon to handle the disk.
bool userZeroStarted = mStartedUsers.find(0) != mStartedUsers.end();
if (mSecureKeyguardShowing) {
LOG(INFO) << "Found disk at " << disk->getEventPath()
<< " but delaying scan due to secure keyguard";
mPendingDisks.push_back(disk);
} else if (!userZeroStarted) {
LOG(INFO) << "Found disk at " << disk->getEventPath()
<< " but delaying scan due to user zero not having started";
mPendingDisks.push_back(disk);
} else {
disk->create();
mDisks.push_back(disk);
}
}
void VolumeManager::handleDiskChanged(dev_t device) {
for (const auto& disk : mDisks) {
if (disk->getDevice() == device) {
disk->readMetadata();
disk->readPartitions();
}
}
// For security reasons, we ignore all pending disks, since
// we'll scan them once the device is unlocked
}
void VolumeManager::handleDiskRemoved(dev_t device) {
auto i = mDisks.begin();
while (i != mDisks.end()) {
if ((*i)->getDevice() == device) {
(*i)->destroy();
i = mDisks.erase(i);
} else {
++i;
}
}
auto j = mPendingDisks.begin();
while (j != mPendingDisks.end()) {
if ((*j)->getDevice() == device) {
j = mPendingDisks.erase(j);
} else {
++j;
}
}
}
void VolumeManager::addDiskSource(const std::shared_ptr<DiskSource>& diskSource) {
std::lock_guard<std::mutex> lock(mLock);
mDiskSources.push_back(diskSource);
}
std::shared_ptr<android::vold::Disk> VolumeManager::findDisk(const std::string& id) {
for (auto disk : mDisks) {
if (disk->getId() == id) {
return disk;
}
}
return nullptr;
}
std::shared_ptr<android::vold::VolumeBase> VolumeManager::findVolume(const std::string& id) {
for (const auto& vol : mInternalEmulatedVolumes) {
if (vol->getId() == id) {
return vol;
}
}
for (const auto& disk : mDisks) {
auto vol = disk->findVolume(id);
if (vol != nullptr) {
return vol;
}
}
for (const auto& vol : mObbVolumes) {
if (vol->getId() == id) {
return vol;
}
}
return nullptr;
}
void VolumeManager::listVolumes(android::vold::VolumeBase::Type type,
std::list<std::string>& list) const {
list.clear();
for (const auto& disk : mDisks) {
disk->listVolumes(type, list);
}
}
int VolumeManager::forgetPartition(const std::string& partGuid, const std::string& fsUuid) {
std::string normalizedGuid;
if (android::vold::NormalizeHex(partGuid, normalizedGuid)) {
LOG(WARNING) << "Invalid GUID " << partGuid;
return -1;
}
bool success = true;
std::string keyPath = android::vold::BuildKeyPath(normalizedGuid);
if (unlink(keyPath.c_str()) != 0) {
LOG(ERROR) << "Failed to unlink " << keyPath;
success = false;
}
if (fscrypt_is_native()) {
if (!fscrypt_destroy_volume_keys(fsUuid)) {
success = false;
}
}
return success ? 0 : -1;
}
void VolumeManager::destroyEmulatedVolumesForUser(userid_t userId) {
// Destroy and remove all unstacked EmulatedVolumes for the user
auto i = mInternalEmulatedVolumes.begin();
while (i != mInternalEmulatedVolumes.end()) {
auto vol = *i;
if (vol->getMountUserId() == userId) {
vol->destroy();
i = mInternalEmulatedVolumes.erase(i);
} else {
i++;
}
}
// Destroy and remove all stacked EmulatedVolumes for the user on each mounted private volume
std::list<std::string> private_vols;
listVolumes(VolumeBase::Type::kPrivate, private_vols);
for (const std::string& id : private_vols) {
PrivateVolume* pvol = static_cast<PrivateVolume*>(findVolume(id).get());
std::list<std::shared_ptr<VolumeBase>> vols_to_remove;
if (pvol->getState() == VolumeBase::State::kMounted) {
for (const auto& vol : pvol->getVolumes()) {
if (vol->getMountUserId() == userId) {
vols_to_remove.push_back(vol);
}
}
for (const auto& vol : vols_to_remove) {
vol->destroy();
pvol->removeVolume(vol);
}
} // else EmulatedVolumes will be destroyed on VolumeBase#unmount
}
}
void VolumeManager::createEmulatedVolumesForUser(userid_t userId) {
// Create unstacked EmulatedVolumes for the user
auto vol = std::shared_ptr<android::vold::VolumeBase>(
new android::vold::EmulatedVolume("/data/media", userId));
vol->setMountUserId(userId);
mInternalEmulatedVolumes.push_back(vol);
vol->create();
// Create stacked EmulatedVolumes for the user on each PrivateVolume
std::list<std::string> private_vols;
listVolumes(VolumeBase::Type::kPrivate, private_vols);
for (const std::string& id : private_vols) {
PrivateVolume* pvol = static_cast<PrivateVolume*>(findVolume(id).get());
if (pvol->getState() == VolumeBase::State::kMounted) {
auto evol =
std::shared_ptr<android::vold::VolumeBase>(new android::vold::EmulatedVolume(
pvol->getPath() + "/media", pvol->getRawDevice(), pvol->getFsUuid(),
userId));
evol->setMountUserId(userId);
pvol->addVolume(evol);
evol->create();
} // else EmulatedVolumes will be created per user when on PrivateVolume#doMount
}
}
int VolumeManager::onUserAdded(userid_t userId, int userSerialNumber) {
LOG(INFO) << "onUserAdded: " << userId;
mAddedUsers[userId] = userSerialNumber;
return 0;
}
int VolumeManager::onUserRemoved(userid_t userId) {
LOG(INFO) << "onUserRemoved: " << userId;
onUserStopped(userId);
mAddedUsers.erase(userId);
return 0;
}
int VolumeManager::onUserStarted(userid_t userId) {
LOG(INFO) << "onUserStarted: " << userId;
if (mStartedUsers.find(userId) == mStartedUsers.end()) {
createEmulatedVolumesForUser(userId);
}
mStartedUsers.insert(userId);
createPendingDisksIfNeeded();
return 0;
}
int VolumeManager::onUserStopped(userid_t userId) {
LOG(VERBOSE) << "onUserStopped: " << userId;
if (mStartedUsers.find(userId) != mStartedUsers.end()) {
destroyEmulatedVolumesForUser(userId);
}
mStartedUsers.erase(userId);
return 0;
}
void VolumeManager::createPendingDisksIfNeeded() {
bool userZeroStarted = mStartedUsers.find(0) != mStartedUsers.end();
if (!mSecureKeyguardShowing && userZeroStarted) {
// Now that secure keyguard has been dismissed and user 0 has
// started, process any pending disks
for (const auto& disk : mPendingDisks) {
disk->create();
mDisks.push_back(disk);
}
mPendingDisks.clear();
}
}
int VolumeManager::onSecureKeyguardStateChanged(bool isShowing) {
mSecureKeyguardShowing = isShowing;
createPendingDisksIfNeeded();
return 0;
}
// This code is executed after a fork so it's very important that the set of
// methods we call here is strictly limited.
//
// TODO: Get rid of this guesswork altogether and instead exec a process
// immediately after fork to do our bindding for us.
static bool childProcess(const char* storageSource, const char* userSource, int nsFd,
const char* name) {
if (setns(nsFd, CLONE_NEWNS) != 0) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to setns for %s :%s", name,
strerror(errno));
return false;
}
// NOTE: Inlined from vold::UnmountTree here to avoid using PLOG methods and
// to also protect against future changes that may cause issues across a
// fork.
if (TEMP_FAILURE_RETRY(umount2("/storage/", MNT_DETACH)) < 0 && errno != EINVAL &&
errno != ENOENT) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to unmount /storage/ :%s",
strerror(errno));
return false;
}
if (TEMP_FAILURE_RETRY(mount(storageSource, "/storage", NULL, MS_BIND | MS_REC, NULL)) == -1) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to mount %s for %s :%s",
storageSource, name, strerror(errno));
return false;
}
if (TEMP_FAILURE_RETRY(mount(NULL, "/storage", NULL, MS_REC | MS_SLAVE, NULL)) == -1) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold",
"Failed to set MS_SLAVE to /storage for %s :%s", name,
strerror(errno));
return false;
}
if (TEMP_FAILURE_RETRY(mount(userSource, "/storage/self", NULL, MS_BIND, NULL)) == -1) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to mount %s for %s :%s",
userSource, name, strerror(errno));
return false;
}
return true;
}
// Fork the process and remount storage
bool forkAndRemountChild(uid_t uid, pid_t pid, int nsFd, const char* name, void* params) {
int32_t mountMode = *static_cast<int32_t*>(params);
std::string userSource;
std::string storageSource;
pid_t child;
// Need to fix these paths to account for when sdcardfs is gone
switch (mountMode) {
case VoldNativeService::REMOUNT_MODE_NONE:
return true;
case VoldNativeService::REMOUNT_MODE_DEFAULT:
storageSource = "/mnt/runtime/default";
break;
case VoldNativeService::REMOUNT_MODE_ANDROID_WRITABLE:
case VoldNativeService::REMOUNT_MODE_INSTALLER:
storageSource = "/mnt/runtime/write";
break;
case VoldNativeService::REMOUNT_MODE_PASS_THROUGH:
return true;
default:
PLOG(ERROR) << "Unknown mode " << std::to_string(mountMode);
return false;
}
LOG(DEBUG) << "Remounting " << uid << " as " << storageSource;
// Fork a child to mount user-specific symlink helper into place
userSource = StringPrintf("/mnt/user/%d", multiuser_get_user_id(uid));
if (!(child = fork())) {
if (childProcess(storageSource.c_str(), userSource.c_str(), nsFd, name)) {
_exit(0);
} else {
_exit(1);
}
}
if (child == -1) {
PLOG(ERROR) << "Failed to fork";
return false;
} else {
TEMP_FAILURE_RETRY(waitpid(child, nullptr, 0));
}
return true;
}
// Helper function to scan all processes in /proc and call the callback if:
// 1). pid belongs to an app process
// 2). If input uid is 0 or it matches the process uid
// 3). If userId is not -1 or userId matches the process userId
bool scanProcProcesses(uid_t uid, userid_t userId, ScanProcCallback callback, void* params) {
DIR* dir;
struct dirent* de;
std::string rootName;
std::string pidName;
int pidFd;
int nsFd;
struct stat sb;
static bool apexUpdatable = android::sysprop::ApexProperties::updatable().value_or(false);
if (!(dir = opendir("/proc"))) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to opendir");
return false;
}
// Figure out root namespace to compare against below
if (!android::vold::Readlinkat(dirfd(dir), "1/ns/mnt", &rootName)) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to read root namespace");
closedir(dir);
return false;
}
async_safe_format_log(ANDROID_LOG_INFO, "vold", "Start scanning all processes");
// Poke through all running PIDs look for apps running as UID
while ((de = readdir(dir))) {
pid_t pid;
if (de->d_type != DT_DIR) continue;
if (!android::base::ParseInt(de->d_name, &pid)) continue;
pidFd = -1;
nsFd = -1;
pidFd = openat(dirfd(dir), de->d_name, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
if (pidFd < 0) {
goto next;
}
if (fstat(pidFd, &sb) != 0) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to stat %s", de->d_name);
goto next;
}
if (uid != 0 && sb.st_uid != uid) {
goto next;
}
if (userId != static_cast<userid_t>(-1) && multiuser_get_user_id(sb.st_uid) != userId) {
goto next;
}
// Matches so far, but refuse to touch if in root namespace
if (!android::vold::Readlinkat(pidFd, "ns/mnt", &pidName)) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold",
"Failed to read namespacefor %s", de->d_name);
goto next;
}
if (rootName == pidName) {
goto next;
}
if (apexUpdatable) {
std::string exeName;
// When ro.apex.bionic_updatable is set to true,
// some early native processes have mount namespaces that are different
// from that of the init. Therefore, above check can't filter them out.
// Since the propagation type of / is 'shared', unmounting /storage
// for the early native processes affects other processes including
// init. Filter out such processes by skipping if a process is a
// non-Java process whose UID is < AID_APP_START. (The UID condition
// is required to not filter out child processes spawned by apps.)
if (!android::vold::Readlinkat(pidFd, "exe", &exeName)) {
goto next;
}
if (!StartsWith(exeName, "/system/bin/app_process") && sb.st_uid < AID_APP_START) {
goto next;
}
}
// We purposefully leave the namespace open across the fork
// NOLINTNEXTLINE(android-cloexec-open): Deliberately not O_CLOEXEC
nsFd = openat(pidFd, "ns/mnt", O_RDONLY);
if (nsFd < 0) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold",
"Failed to open namespace for %s", de->d_name);
goto next;
}
if (!callback(sb.st_uid, pid, nsFd, de->d_name, params)) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed in callback");
}
next:
close(nsFd);
close(pidFd);
}
closedir(dir);
async_safe_format_log(ANDROID_LOG_INFO, "vold", "Finished scanning all processes");
return true;
}
// In each app's namespace, unmount obb and data dirs
static bool umountStorageDirs(int nsFd, const char* android_data_dir, const char* android_obb_dir,
int uid, const char* targets[], int size) {
// This code is executed after a fork so it's very important that the set of
// methods we call here is strictly limited.
if (setns(nsFd, CLONE_NEWNS) != 0) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to setns %s", strerror(errno));
return false;
}
// Unmount of Android/data/foo needs to be done before Android/data below.
bool result = true;
for (int i = 0; i < size; i++) {
if (TEMP_FAILURE_RETRY(umount2(targets[i], MNT_DETACH)) < 0 && errno != EINVAL &&
errno != ENOENT) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to umount %s: %s",
targets[i], strerror(errno));
result = false;
}
}
// Mount tmpfs on Android/data and Android/obb
if (TEMP_FAILURE_RETRY(umount2(android_data_dir, MNT_DETACH)) < 0 && errno != EINVAL &&
errno != ENOENT) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to umount %s :%s",
android_data_dir, strerror(errno));
result = false;
}
if (TEMP_FAILURE_RETRY(umount2(android_obb_dir, MNT_DETACH)) < 0 && errno != EINVAL &&
errno != ENOENT) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to umount %s :%s",
android_obb_dir, strerror(errno));
result = false;
}
return result;
}
// In each app's namespace, mount tmpfs on obb and data dir, and bind mount obb and data
// package dirs.
static bool remountStorageDirs(int nsFd, const char* android_data_dir, const char* android_obb_dir,
int uid, const char* sources[], const char* targets[], int size) {
// This code is executed after a fork so it's very important that the set of
// methods we call here is strictly limited.
if (setns(nsFd, CLONE_NEWNS) != 0) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to setns %s", strerror(errno));
return false;
}
// Mount tmpfs on Android/data and Android/obb
if (TEMP_FAILURE_RETRY(mount("tmpfs", android_data_dir, "tmpfs",
MS_NOSUID | MS_NODEV | MS_NOEXEC, "uid=0,gid=0,mode=0751")) == -1) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to mount tmpfs to %s :%s",
android_data_dir, strerror(errno));
return false;
}
if (TEMP_FAILURE_RETRY(mount("tmpfs", android_obb_dir, "tmpfs",
MS_NOSUID | MS_NODEV | MS_NOEXEC, "uid=0,gid=0,mode=0751")) == -1) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to mount tmpfs to %s :%s",
android_obb_dir, strerror(errno));
return false;
}
for (int i = 0; i < size; i++) {
// Create package dir and bind mount it to the actual one.
if (TEMP_FAILURE_RETRY(mkdir(targets[i], 0700)) == -1) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to mkdir %s %s",
targets[i], strerror(errno));
return false;
}
if (TEMP_FAILURE_RETRY(mount(sources[i], targets[i], NULL, MS_BIND | MS_REC, NULL)) == -1) {
async_safe_format_log(ANDROID_LOG_ERROR, "vold", "Failed to mount %s to %s :%s",
sources[i], targets[i], strerror(errno));
return false;
}
}
return true;
}
static std::string getStorageDirSrc(userid_t userId, const std::string& dirName,
const std::string& packageName) {
if (IsSdcardfsUsed()) {
return StringPrintf("/mnt/runtime/default/emulated/%d/%s/%s",
userId, dirName.c_str(), packageName.c_str());
} else {
return StringPrintf("/mnt/pass_through/%d/emulated/%d/%s/%s",
userId, userId, dirName.c_str(), packageName.c_str());
}
}
static std::string getStorageDirTarget(userid_t userId, std::string dirName,
std::string packageName) {
return StringPrintf("/storage/emulated/%d/%s/%s",
userId, dirName.c_str(), packageName.c_str());
}
// Fork the process and remount / unmount app data and obb dirs
bool VolumeManager::forkAndRemountStorage(int uid, int pid, bool doUnmount,
const std::vector<std::string>& packageNames) {
userid_t userId = multiuser_get_user_id(uid);
std::string mnt_path = StringPrintf("/proc/%d/ns/mnt", pid);
android::base::unique_fd nsFd(
TEMP_FAILURE_RETRY(open(mnt_path.c_str(), O_RDONLY | O_CLOEXEC)));
if (nsFd == -1) {
PLOG(ERROR) << "Unable to open " << mnt_path.c_str();
return false;
}
// Storing both Android/obb and Android/data paths.
int size = packageNames.size() * 2;
std::unique_ptr<std::string[]> sources(new std::string[size]);
std::unique_ptr<std::string[]> targets(new std::string[size]);
std::unique_ptr<const char*[]> sources_uptr(new const char*[size]);
std::unique_ptr<const char*[]> targets_uptr(new const char*[size]);
const char** sources_cstr = sources_uptr.get();
const char** targets_cstr = targets_uptr.get();
for (int i = 0; i < size; i += 2) {
std::string const& packageName = packageNames[i/2];
sources[i] = getStorageDirSrc(userId, "Android/data", packageName);
targets[i] = getStorageDirTarget(userId, "Android/data", packageName);
sources[i+1] = getStorageDirSrc(userId, "Android/obb", packageName);
targets[i+1] = getStorageDirTarget(userId, "Android/obb", packageName);
sources_cstr[i] = sources[i].c_str();
targets_cstr[i] = targets[i].c_str();
sources_cstr[i+1] = sources[i+1].c_str();
targets_cstr[i+1] = targets[i+1].c_str();
}
for (int i = 0; i < size; i++) {
// Make sure /storage/emulated/... paths are setup correctly
// This needs to be done before EnsureDirExists to ensure Android/ is created.
auto status = setupAppDir(targets_cstr[i], uid, false /* fixupExistingOnly */);
if (status != OK) {
PLOG(ERROR) << "Failed to create dir: " << targets_cstr[i];
return false;
}
status = EnsureDirExists(sources_cstr[i], 0771, AID_MEDIA_RW, AID_MEDIA_RW);
if (status != OK) {
PLOG(ERROR) << "Failed to create dir: " << sources_cstr[i];
return false;
}
}
char android_data_dir[PATH_MAX];
char android_obb_dir[PATH_MAX];
snprintf(android_data_dir, PATH_MAX, "/storage/emulated/%d/Android/data", userId);
snprintf(android_obb_dir, PATH_MAX, "/storage/emulated/%d/Android/obb", userId);
pid_t child;
// Fork a child to mount Android/obb android Android/data dirs, as we don't want it to affect
// original vold process mount namespace.
if (!(child = fork())) {
if (doUnmount) {
if (umountStorageDirs(nsFd, android_data_dir, android_obb_dir, uid,
targets_cstr, size)) {
_exit(0);
} else {
_exit(1);
}
} else {
if (remountStorageDirs(nsFd, android_data_dir, android_obb_dir, uid,
sources_cstr, targets_cstr, size)) {
_exit(0);
} else {
_exit(1);
}
}
}
if (child == -1) {
PLOG(ERROR) << "Failed to fork";
return false;
} else {
int status;
if (TEMP_FAILURE_RETRY(waitpid(child, &status, 0)) == -1) {
PLOG(ERROR) << "Failed to waitpid: " << child;
return false;
}
if (!WIFEXITED(status)) {
PLOG(ERROR) << "Process did not exit normally, status: " << status;
return false;
}
if (WEXITSTATUS(status)) {
PLOG(ERROR) << "Process exited with code: " << WEXITSTATUS(status);
return false;
}
}
return true;
}
int VolumeManager::handleAppStorageDirs(int uid, int pid,
bool doUnmount, const std::vector<std::string>& packageNames) {
// Only run the remount if fuse is mounted for that user.
userid_t userId = multiuser_get_user_id(uid);
bool fuseMounted = false;
for (auto& vol : mInternalEmulatedVolumes) {
if (vol->getMountUserId() == userId && vol->getState() == VolumeBase::State::kMounted) {
auto* emulatedVol = static_cast<android::vold::EmulatedVolume*>(vol.get());
if (emulatedVol) {
fuseMounted = emulatedVol->isFuseMounted();
}
break;
}
}
if (fuseMounted) {
forkAndRemountStorage(uid, pid, doUnmount, packageNames);
}
return 0;
}
int VolumeManager::abortFuse() {
return android::vold::AbortFuseConnections();
}
int VolumeManager::reset() {
// Tear down all existing disks/volumes and start from a blank slate so
// newly connected framework hears all events.
for (const auto& vol : mInternalEmulatedVolumes) {
vol->destroy();
}
mInternalEmulatedVolumes.clear();
// Destroy and recreate all disks except that StubVolume disks are just
// destroyed and removed from both mDisks and mPendingDisks.
// StubVolumes are managed from outside Android (e.g. from Chrome OS) and
// their disk recreation on reset events should be handled from outside by
// calling createStubVolume() again.
for (const auto& disk : mDisks) {
disk->destroy();
if (!disk->isStub()) {
disk->create();
}
}
const auto isStub = [](const auto& disk) { return disk->isStub(); };
mDisks.remove_if(isStub);
mPendingDisks.remove_if(isStub);
updateVirtualDisk();
mAddedUsers.clear();
mStartedUsers.clear();
return 0;
}
// Can be called twice (sequentially) during shutdown. should be safe for that.
int VolumeManager::shutdown() {
if (mInternalEmulatedVolumes.empty()) {
return 0; // already shutdown
}
android::vold::sSleepOnUnmount = false;
for (const auto& vol : mInternalEmulatedVolumes) {
vol->destroy();
}
for (const auto& disk : mDisks) {
disk->destroy();
}
mInternalEmulatedVolumes.clear();
mDisks.clear();
mPendingDisks.clear();
android::vold::sSleepOnUnmount = true;
return 0;
}
int VolumeManager::unmountAll() {
std::lock_guard<std::mutex> lock(mLock);
ATRACE_NAME("VolumeManager::unmountAll()");
// First, try gracefully unmounting all known devices
for (const auto& vol : mInternalEmulatedVolumes) {
vol->unmount();
}
for (const auto& disk : mDisks) {
disk->unmountAll();
}
// Worst case we might have some stale mounts lurking around, so
// force unmount those just to be safe.
FILE* fp = setmntent("/proc/mounts", "re");
if (fp == NULL) {
PLOG(ERROR) << "Failed to open /proc/mounts";
return -errno;
}
// Some volumes can be stacked on each other, so force unmount in
// reverse order to give us the best chance of success.
std::list<std::string> toUnmount;
mntent* mentry;
while ((mentry = getmntent(fp)) != NULL) {
auto test = std::string(mentry->mnt_dir);
if ((StartsWith(test, "/mnt/") &&
#ifdef __ANDROID_DEBUGGABLE__
!StartsWith(test, "/mnt/scratch") &&
#endif
!StartsWith(test, "/mnt/vendor") && !StartsWith(test, "/mnt/product") &&
!StartsWith(test, "/mnt/installer") && !StartsWith(test, "/mnt/androidwritable")) ||
StartsWith(test, "/storage/")) {
toUnmount.push_front(test);
}
}
endmntent(fp);
for (const auto& path : toUnmount) {
LOG(DEBUG) << "Tearing down stale mount " << path;
android::vold::ForceUnmount(path);
}
return 0;
}
int VolumeManager::ensureAppDirsCreated(const std::vector<std::string>& paths, int32_t appUid) {
int size = paths.size();
for (int i = 0; i < size; i++) {
int result = setupAppDir(paths[i], appUid, false /* fixupExistingOnly */,
true /* skipIfDirExists */);
if (result != OK) {
return result;
}
}
return OK;
}
int VolumeManager::setupAppDir(const std::string& path, int32_t appUid, bool fixupExistingOnly,
bool skipIfDirExists) {
// Only offer to create directories for paths managed by vold
if (!StartsWith(path, "/storage/")) {
LOG(ERROR) << "Failed to find mounted volume for " << path;
return -EINVAL;
}
// Find the volume it belongs to
auto filter_fn = [&](const VolumeBase& vol) {
if (vol.getState() != VolumeBase::State::kMounted) {
// The volume must be mounted
return false;
}
if (!vol.isVisibleForWrite()) {
// App dirs should only be created for writable volumes.
return false;
}
if (vol.getInternalPath().empty()) {
return false;
}
if (vol.getMountUserId() != USER_UNKNOWN &&
vol.getMountUserId() != multiuser_get_user_id(appUid)) {
// The app dir must be created on a volume with the same user-id
return false;
}
if (!path.empty() && StartsWith(path, vol.getPath())) {
return true;
}
return false;
};
auto volume = findVolumeWithFilter(filter_fn);
if (volume == nullptr) {
LOG(ERROR) << "Failed to find mounted volume for " << path;
return -EINVAL;
}
// Convert paths to lower filesystem paths to avoid making FUSE requests for these reasons:
// 1. A FUSE request from vold puts vold at risk of hanging if the FUSE daemon is down
// 2. The FUSE daemon prevents requests on /mnt/user/0/emulated/<userid != 0> and a request
// on /storage/emulated/10 means /mnt/user/0/emulated/10
const std::string lowerPath =
volume->getInternalPath() + path.substr(volume->getPath().length());
const std::string volumeRoot = volume->getRootPath(); // eg /data/media/0
const int access_result = access(lowerPath.c_str(), F_OK);
if (fixupExistingOnly && access_result != 0) {
// Nothing to fixup
return OK;
}
if (skipIfDirExists && access_result == 0) {
// It's safe to assume it's ok as it will be used for zygote to bind mount dir only,
// which the dir doesn't need to have correct permission for now yet.
return OK;
}
if (volume->getType() == VolumeBase::Type::kPublic) {
// On public volumes, we don't need to setup permissions, as everything goes through
// FUSE; just create the dirs and be done with it.
return fs_mkdirs(lowerPath.c_str(), 0700);
}
// Create the app paths we need from the root
return PrepareAppDirFromRoot(lowerPath, volumeRoot, appUid, fixupExistingOnly);
}
int VolumeManager::fixupAppDir(const std::string& path, int32_t appUid) {
if (IsSdcardfsUsed()) {
//sdcardfs magically does this for us
return OK;
}
return setupAppDir(path, appUid, true /* fixupExistingOnly */);
}
int VolumeManager::createObb(const std::string& sourcePath, int32_t ownerGid,
std::string* outVolId) {
int id = mNextObbId++;
std::string lowerSourcePath;
// Convert to lower filesystem path
if (StartsWith(sourcePath, "/storage/")) {
auto filter_fn = [&](const VolumeBase& vol) {
if (vol.getState() != VolumeBase::State::kMounted) {
// The volume must be mounted
return false;
}
if (!vol.isVisibleForWrite()) {
// Obb volume should only be created for writable volumes.
return false;
}
if (vol.getInternalPath().empty()) {
return false;
}
if (!sourcePath.empty() && StartsWith(sourcePath, vol.getPath())) {
return true;
}
return false;
};
auto volume = findVolumeWithFilter(filter_fn);
if (volume == nullptr) {
LOG(ERROR) << "Failed to find mounted volume for " << sourcePath;
return -EINVAL;
} else {
lowerSourcePath =
volume->getInternalPath() + sourcePath.substr(volume->getPath().length());
}
} else {
lowerSourcePath = sourcePath;
}
auto vol = std::shared_ptr<android::vold::VolumeBase>(
new android::vold::ObbVolume(id, lowerSourcePath, ownerGid));
vol->create();
mObbVolumes.push_back(vol);
*outVolId = vol->getId();
return android::OK;
}
int VolumeManager::destroyObb(const std::string& volId) {
auto i = mObbVolumes.begin();
while (i != mObbVolumes.end()) {
if ((*i)->getId() == volId) {
(*i)->destroy();
i = mObbVolumes.erase(i);
} else {
++i;
}
}
return android::OK;
}
int VolumeManager::createStubVolume(const std::string& sourcePath, const std::string& mountPath,
const std::string& fsType, const std::string& fsUuid,
const std::string& fsLabel, int32_t flags,
std::string* outVolId) {
dev_t stubId = --mNextStubId;
auto vol = std::shared_ptr<android::vold::StubVolume>(
new android::vold::StubVolume(stubId, sourcePath, mountPath, fsType, fsUuid, fsLabel));
int32_t passedFlags = 0;
passedFlags |= (flags & android::vold::Disk::Flags::kUsb);
passedFlags |= (flags & android::vold::Disk::Flags::kSd);
if (flags & android::vold::Disk::Flags::kStubVisible) {
passedFlags |= (flags & android::vold::Disk::Flags::kStubVisible);
} else {
passedFlags |= (flags & android::vold::Disk::Flags::kStubInvisible);
}
// StubDisk doesn't have device node corresponds to it. So, a fake device
// number is used.
auto disk = std::shared_ptr<android::vold::Disk>(
new android::vold::Disk("stub", stubId, "stub", passedFlags));
disk->initializePartition(vol);
handleDiskAdded(disk);
*outVolId = vol->getId();
return android::OK;
}
int VolumeManager::destroyStubVolume(const std::string& volId) {
auto tokens = android::base::Split(volId, ":");
CHECK(tokens.size() == 2);
dev_t stubId;
CHECK(android::base::ParseUint(tokens[1], &stubId));
handleDiskRemoved(stubId);
return android::OK;
}
int VolumeManager::mountAppFuse(uid_t uid, int mountId, unique_fd* device_fd) {
return android::vold::MountAppFuse(uid, mountId, device_fd);
}
int VolumeManager::unmountAppFuse(uid_t uid, int mountId) {
return android::vold::UnmountAppFuse(uid, mountId);
}
int VolumeManager::openAppFuseFile(uid_t uid, int mountId, int fileId, int flags) {
return android::vold::OpenAppFuseFile(uid, mountId, fileId, flags);
}
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