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platform_system_vold/model/PublicVolume.cpp
himanshuz 0ad0862159 Adding public volume mounts for clone user. 
Public SdCard Volumes are mounted only for user 0
(foreground user). This gives ENONT if the cloned
user tries to access the files in SdCard with
paths like "/storage/AB02-G212/DCIM/"

This change adds SdCard Volume mnt under
/mnt/usr/<cloned-user>/ which allows cloned apps
access to SdCard via direct file paths.

Bug: 203395175
Test: Manual by building and flashing device.
Change-Id: I091c40d3cb19915145cd5af40d1e79d5a9ecfa02
2023-08-29 10:38:43 +00:00

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/*
* Copyright (C) 2015 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 "PublicVolume.h"
#include "AppFuseUtil.h"
#include "Utils.h"
#include "VolumeManager.h"
#include "fs/Exfat.h"
#include "fs/Vfat.h"
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <cutils/fs.h>
#include <private/android_filesystem_config.h>
#include <utils/Timers.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <sys/wait.h>
using android::base::GetBoolProperty;
using android::base::StringPrintf;
namespace android {
namespace vold {
static const char* kSdcardFsPath = "/system/bin/sdcard";
static const char* kAsecPath = "/mnt/secure/asec";
PublicVolume::PublicVolume(dev_t device) : VolumeBase(Type::kPublic), mDevice(device) {
setId(StringPrintf("public:%u,%u", major(device), minor(device)));
mDevPath = StringPrintf("/dev/block/vold/%s", getId().c_str());
mFuseMounted = false;
mUseSdcardFs = IsSdcardfsUsed();
}
PublicVolume::~PublicVolume() {}
status_t PublicVolume::readMetadata() {
status_t res = ReadMetadataUntrusted(mDevPath, &mFsType, &mFsUuid, &mFsLabel);
auto listener = getListener();
if (listener) listener->onVolumeMetadataChanged(getId(), mFsType, mFsUuid, mFsLabel);
return res;
}
status_t PublicVolume::initAsecStage() {
std::string legacyPath(mRawPath + "/android_secure");
std::string securePath(mRawPath + "/.android_secure");
// Recover legacy secure path
if (!access(legacyPath.c_str(), R_OK | X_OK) && access(securePath.c_str(), R_OK | X_OK)) {
if (rename(legacyPath.c_str(), securePath.c_str())) {
PLOG(WARNING) << getId() << " failed to rename legacy ASEC dir";
}
}
if (TEMP_FAILURE_RETRY(mkdir(securePath.c_str(), 0700))) {
if (errno != EEXIST) {
PLOG(WARNING) << getId() << " creating ASEC stage failed";
return -errno;
}
}
BindMount(securePath, kAsecPath);
return OK;
}
status_t PublicVolume::doCreate() {
return CreateDeviceNode(mDevPath, mDevice);
}
status_t PublicVolume::doDestroy() {
return DestroyDeviceNode(mDevPath);
}
status_t PublicVolume::doMount() {
bool isVisible = isVisibleForWrite();
readMetadata();
if (mFsType == "vfat" && vfat::IsSupported()) {
if (vfat::Check(mDevPath)) {
LOG(ERROR) << getId() << " failed filesystem check";
return -EIO;
}
} else if (mFsType == "exfat" && exfat::IsSupported()) {
if (exfat::Check(mDevPath)) {
LOG(ERROR) << getId() << " failed filesystem check";
return -EIO;
}
} else {
LOG(ERROR) << getId() << " unsupported filesystem " << mFsType;
return -EIO;
}
// Use UUID as stable name, if available
std::string stableName = getId();
if (!mFsUuid.empty()) {
stableName = mFsUuid;
}
mRawPath = StringPrintf("/mnt/media_rw/%s", stableName.c_str());
mSdcardFsDefault = StringPrintf("/mnt/runtime/default/%s", stableName.c_str());
mSdcardFsRead = StringPrintf("/mnt/runtime/read/%s", stableName.c_str());
mSdcardFsWrite = StringPrintf("/mnt/runtime/write/%s", stableName.c_str());
mSdcardFsFull = StringPrintf("/mnt/runtime/full/%s", stableName.c_str());
setInternalPath(mRawPath);
if (isVisible) {
setPath(StringPrintf("/storage/%s", stableName.c_str()));
} else {
setPath(mRawPath);
}
if (fs_prepare_dir(mRawPath.c_str(), 0700, AID_ROOT, AID_ROOT)) {
PLOG(ERROR) << getId() << " failed to create mount points";
return -errno;
}
if (mFsType == "vfat") {
if (vfat::Mount(mDevPath, mRawPath, false, false, false, AID_ROOT,
(isVisible ? AID_MEDIA_RW : AID_EXTERNAL_STORAGE), 0007, true)) {
PLOG(ERROR) << getId() << " failed to mount " << mDevPath;
return -EIO;
}
} else if (mFsType == "exfat") {
if (exfat::Mount(mDevPath, mRawPath, AID_ROOT,
(isVisible ? AID_MEDIA_RW : AID_EXTERNAL_STORAGE), 0007)) {
PLOG(ERROR) << getId() << " failed to mount " << mDevPath;
return -EIO;
}
}
if (getMountFlags() & MountFlags::kPrimary) {
initAsecStage();
}
if (!isVisible) {
// Not visible to apps, so no need to spin up sdcardfs or FUSE
return OK;
}
if (mUseSdcardFs) {
if (fs_prepare_dir(mSdcardFsDefault.c_str(), 0700, AID_ROOT, AID_ROOT) ||
fs_prepare_dir(mSdcardFsRead.c_str(), 0700, AID_ROOT, AID_ROOT) ||
fs_prepare_dir(mSdcardFsWrite.c_str(), 0700, AID_ROOT, AID_ROOT) ||
fs_prepare_dir(mSdcardFsFull.c_str(), 0700, AID_ROOT, AID_ROOT)) {
PLOG(ERROR) << getId() << " failed to create sdcardfs mount points";
return -errno;
}
dev_t before = GetDevice(mSdcardFsFull);
int sdcardFsPid;
if (!(sdcardFsPid = fork())) {
if (getMountFlags() & MountFlags::kPrimary) {
// clang-format off
if (execl(kSdcardFsPath, kSdcardFsPath,
"-u", "1023", // AID_MEDIA_RW
"-g", "1023", // AID_MEDIA_RW
"-U", std::to_string(getMountUserId()).c_str(),
"-w",
mRawPath.c_str(),
stableName.c_str(),
NULL)) {
// clang-format on
PLOG(ERROR) << "Failed to exec";
}
} else {
// clang-format off
if (execl(kSdcardFsPath, kSdcardFsPath,
"-u", "1023", // AID_MEDIA_RW
"-g", "1023", // AID_MEDIA_RW
"-U", std::to_string(getMountUserId()).c_str(),
mRawPath.c_str(),
stableName.c_str(),
NULL)) {
// clang-format on
PLOG(ERROR) << "Failed to exec";
}
}
LOG(ERROR) << "sdcardfs exiting";
_exit(1);
}
if (sdcardFsPid == -1) {
PLOG(ERROR) << getId() << " failed to fork";
return -errno;
}
nsecs_t start = systemTime(SYSTEM_TIME_BOOTTIME);
while (before == GetDevice(mSdcardFsFull)) {
LOG(DEBUG) << "Waiting for sdcardfs to spin up...";
usleep(50000); // 50ms
nsecs_t now = systemTime(SYSTEM_TIME_BOOTTIME);
if (nanoseconds_to_milliseconds(now - start) > 5000) {
LOG(WARNING) << "Timed out while waiting for sdcardfs to spin up";
return -ETIMEDOUT;
}
}
/* sdcardfs will have exited already. The filesystem will still be running */
TEMP_FAILURE_RETRY(waitpid(sdcardFsPid, nullptr, 0));
}
// We need to mount FUSE *after* sdcardfs, since the FUSE daemon may depend
// on sdcardfs being up.
LOG(INFO) << "Mounting public fuse volume";
android::base::unique_fd fd;
int user_id = getMountUserId();
int result = MountUserFuse(user_id, getInternalPath(), stableName, &fd);
if (result != 0) {
LOG(ERROR) << "Failed to mount public fuse volume";
doUnmount();
return -result;
}
mFuseMounted = true;
auto callback = getMountCallback();
if (callback) {
bool is_ready = false;
callback->onVolumeChecking(std::move(fd), getPath(), getInternalPath(), &is_ready);
if (!is_ready) {
LOG(ERROR) << "Failed to complete public volume mount";
doUnmount();
return -EIO;
}
}
ConfigureReadAheadForFuse(GetFuseMountPathForUser(user_id, stableName), 256u);
// See comment in model/EmulatedVolume.cpp
ConfigureMaxDirtyRatioForFuse(GetFuseMountPathForUser(user_id, stableName), 40u);
auto vol_manager = VolumeManager::Instance();
// Create bind mounts for all running users
for (userid_t started_user : vol_manager->getStartedUsers()) {
userid_t mountUserId = getMountUserId();
if (started_user == mountUserId) {
// No need to bind mount for the user that owns the mount
continue;
}
if (mountUserId != VolumeManager::Instance()->getSharedStorageUser(started_user)) {
// No need to bind if the user does not share storage with the mount owner
continue;
}
auto bindMountStatus = bindMountForUser(started_user);
if (bindMountStatus != OK) {
LOG(ERROR) << "Bind Mounting Public Volume: " << stableName
<< " for user: " << started_user << "Failed. Error: " << bindMountStatus;
}
}
return OK;
}
status_t PublicVolume::bindMountForUser(userid_t user_id) {
userid_t mountUserId = getMountUserId();
std::string stableName = getId();
if (!mFsUuid.empty()) {
stableName = mFsUuid;
}
LOG(INFO) << "Bind Mounting Public Volume for user: " << user_id
<< ".Mount owner: " << mountUserId;
auto sourcePath = GetFuseMountPathForUser(mountUserId, stableName);
auto destPath = GetFuseMountPathForUser(user_id, stableName);
PrepareDir(destPath, 0770, AID_ROOT, AID_MEDIA_RW);
auto mountRes = BindMount(sourcePath, destPath);
LOG(INFO) << "Mount status: " << mountRes;
return mountRes;
}
status_t PublicVolume::doUnmount() {
// Unmount the storage before we kill the FUSE process. If we kill
// the FUSE process first, most file system operations will return
// ENOTCONN until the unmount completes. This is an exotic and unusual
// error code and might cause broken behaviour in applications.
KillProcessesUsingPath(getPath());
if (mFuseMounted) {
// Use UUID as stable name, if available
std::string stableName = getId();
if (!mFsUuid.empty()) {
stableName = mFsUuid;
}
// Unmount bind mounts for running users
auto vol_manager = VolumeManager::Instance();
int user_id = getMountUserId();
for (int started_user : vol_manager->getStartedUsers()) {
if (started_user == user_id) {
// No need to remove bind mount for the user that owns the mount
continue;
}
LOG(INFO) << "Removing Public Volume Bind Mount for: " << started_user;
auto mountPath = GetFuseMountPathForUser(started_user, stableName);
ForceUnmount(mountPath);
rmdir(mountPath.c_str());
}
if (UnmountUserFuse(getMountUserId(), getInternalPath(), stableName) != OK) {
PLOG(INFO) << "UnmountUserFuse failed on public fuse volume";
return -errno;
}
mFuseMounted = false;
}
ForceUnmount(kAsecPath);
if (mUseSdcardFs) {
ForceUnmount(mSdcardFsDefault);
ForceUnmount(mSdcardFsRead);
ForceUnmount(mSdcardFsWrite);
ForceUnmount(mSdcardFsFull);
rmdir(mSdcardFsDefault.c_str());
rmdir(mSdcardFsRead.c_str());
rmdir(mSdcardFsWrite.c_str());
rmdir(mSdcardFsFull.c_str());
mSdcardFsDefault.clear();
mSdcardFsRead.clear();
mSdcardFsWrite.clear();
mSdcardFsFull.clear();
}
if (ForceUnmount(mRawPath) != 0){
umount2(mRawPath.c_str(),MNT_DETACH);
PLOG(INFO) << "use umount lazy if force unmount fail";
}
if(rmdir(mRawPath.c_str()) != 0) {
PLOG(INFO) << "rmdir mRawPath=" << mRawPath << " fail";
KillProcessesUsingPath(getPath());
}
mRawPath.clear();
return OK;
}
status_t PublicVolume::doFormat(const std::string& fsType) {
bool isVfatSup = vfat::IsSupported();
bool isExfatSup = exfat::IsSupported();
status_t res = OK;
enum { NONE, VFAT, EXFAT } fsPick = NONE;
// Resolve auto requests
if (fsType == "auto" && isVfatSup && isExfatSup) {
uint64_t size = 0;
res = GetBlockDevSize(mDevPath, &size);
if (res != OK) {
LOG(ERROR) << "Couldn't get device size " << mDevPath;
return res;
}
// If both vfat & exfat are supported use exfat for SDXC (>~32GiB) cards
if (size > 32896LL * 1024 * 1024) {
fsPick = EXFAT;
} else {
fsPick = VFAT;
}
} else if (fsType == "auto" && isExfatSup) {
fsPick = EXFAT;
} else if (fsType == "auto" && isVfatSup) {
fsPick = VFAT;
}
// Resolve explicit requests
if (fsType == "vfat" && isVfatSup) {
fsPick = VFAT;
} else if (fsType == "exfat" && isExfatSup) {
fsPick = EXFAT;
}
if (WipeBlockDevice(mDevPath) != OK) {
LOG(WARNING) << getId() << " failed to wipe";
}
if (fsPick == VFAT) {
res = vfat::Format(mDevPath, 0);
} else if (fsPick == EXFAT) {
res = exfat::Format(mDevPath);
} else {
LOG(ERROR) << "Unsupported filesystem " << fsType;
return -EINVAL;
}
if (res != OK) {
LOG(ERROR) << getId() << " failed to format";
res = -errno;
}
return res;
}
} // namespace vold
} // namespace android
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