blob: 2cc0d2d5ea9cf5746c69cca1905053718a50faef [file] [log] [blame]
/*
* Copyright (C) 2018 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/fs.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <sys/types.h>
#include <unistd.h>
#include <algorithm>
#include <memory>
#include <optional>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <android-base/properties.h>
#include <android-base/strings.h>
#include <fs_mgr.h>
#include <fs_mgr_dm_linear.h>
#include <fs_mgr_overlayfs.h>
#include <fstab/fstab.h>
#include <libdm/dm.h>
#include <libfiemap/image_manager.h>
#include <libgsi/libgsi.h>
#include <liblp/builder.h>
#include <liblp/liblp.h>
#include <storage_literals/storage_literals.h>
#include "fs_mgr_overlayfs_control.h"
#include "fs_mgr_overlayfs_mount.h"
#include "fs_mgr_priv.h"
#include "libfiemap/utility.h"
using namespace std::literals;
using namespace android::dm;
using namespace android::fs_mgr;
using namespace android::storage_literals;
using android::fiemap::FilesystemHasReliablePinning;
using android::fiemap::IImageManager;
namespace {
constexpr char kDataScratchSizeMbProp[] = "fs_mgr.overlayfs.data_scratch_size_mb";
constexpr char kPhysicalDevice[] = "/dev/block/by-name/";
constexpr char kScratchImageMetadata[] = "/metadata/gsi/remount/lp_metadata";
constexpr char kMkF2fs[] = "/system/bin/make_f2fs";
constexpr char kMkExt4[] = "/system/bin/mke2fs";
// Return true if everything is mounted, but before adb is started. Right
// after 'trigger load_persist_props_action' is done.
static bool fs_mgr_boot_completed() {
return android::base::GetBoolProperty("ro.persistent_properties.ready", false);
}
// Note: this is meant only for recovery/first-stage init.
static bool ScratchIsOnData() {
// The scratch partition of DSU is managed by gsid.
if (fs_mgr_is_dsu_running()) {
return false;
}
return access(kScratchImageMetadata, F_OK) == 0;
}
static bool fs_mgr_rm_all(const std::string& path, bool* change = nullptr, int level = 0) {
std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(path.c_str()), closedir);
if (!dir) {
if (errno == ENOENT) {
return true;
}
PERROR << "opendir " << path << " depth=" << level;
if ((errno == EPERM) && (level != 0)) {
return true;
}
return false;
}
dirent* entry;
auto ret = true;
while ((entry = readdir(dir.get()))) {
if (("."s == entry->d_name) || (".."s == entry->d_name)) continue;
auto file = path + "/" + entry->d_name;
if (entry->d_type == DT_UNKNOWN) {
struct stat st;
if (!lstat(file.c_str(), &st) && (st.st_mode & S_IFDIR)) entry->d_type = DT_DIR;
}
if (entry->d_type == DT_DIR) {
ret &= fs_mgr_rm_all(file, change, level + 1);
if (!rmdir(file.c_str())) {
if (change) *change = true;
} else {
if (errno != ENOENT) ret = false;
PERROR << "rmdir " << file << " depth=" << level;
}
continue;
}
if (!unlink(file.c_str())) {
if (change) *change = true;
} else {
if (errno != ENOENT) ret = false;
PERROR << "rm " << file << " depth=" << level;
}
}
return ret;
}
std::string fs_mgr_overlayfs_setup_dir(const std::string& dir) {
auto top = dir + "/" + kOverlayTopDir;
AutoSetFsCreateCon createcon(kOverlayfsFileContext);
if (!createcon.Ok()) {
return {};
}
if (mkdir(top.c_str(), 0755) != 0 && errno != EEXIST) {
PERROR << "mkdir " << top;
return {};
}
if (!createcon.Restore()) {
return {};
}
return top;
}
bool fs_mgr_overlayfs_setup_one(const std::string& overlay, const std::string& mount_point,
bool* want_reboot) {
if (fs_mgr_overlayfs_already_mounted(mount_point)) {
return true;
}
auto fsrec_mount_point = overlay + "/" + android::base::Basename(mount_point) + "/";
AutoSetFsCreateCon createcon(kOverlayfsFileContext);
if (!createcon.Ok()) {
return false;
}
if (mkdir(fsrec_mount_point.c_str(), 0755) != 0 && errno != EEXIST) {
PERROR << "mkdir " << fsrec_mount_point;
return false;
}
if (mkdir((fsrec_mount_point + kWorkName).c_str(), 0755) != 0 && errno != EEXIST) {
PERROR << "mkdir " << fsrec_mount_point << kWorkName;
return false;
}
if (!createcon.Restore()) {
return false;
}
createcon = {};
auto new_context = fs_mgr_get_context(mount_point);
if (new_context.empty() || !createcon.Set(new_context)) {
return false;
}
auto upper = fsrec_mount_point + kUpperName;
if (mkdir(upper.c_str(), 0755) != 0 && errno != EEXIST) {
PERROR << "mkdir " << upper;
return false;
}
if (!createcon.Restore()) {
return false;
}
if (want_reboot) *want_reboot = true;
return true;
}
static uint32_t fs_mgr_overlayfs_slot_number() {
return SlotNumberForSlotSuffix(fs_mgr_get_slot_suffix());
}
static bool fs_mgr_overlayfs_has_logical(const Fstab& fstab) {
for (const auto& entry : fstab) {
if (entry.fs_mgr_flags.logical) {
return true;
}
}
return false;
}
OverlayfsTeardownResult TeardownDataScratch(IImageManager* images,
const std::string& partition_name, bool was_mounted) {
if (!images) {
return OverlayfsTeardownResult::Error;
}
if (!images->DisableImage(partition_name)) {
return OverlayfsTeardownResult::Error;
}
if (was_mounted) {
// If overlayfs was mounted, don't bother trying to unmap since
// it'll fail and create error spam.
return OverlayfsTeardownResult::Busy;
}
if (!images->UnmapImageIfExists(partition_name)) {
return OverlayfsTeardownResult::Busy;
}
if (!images->DeleteBackingImage(partition_name)) {
return OverlayfsTeardownResult::Busy;
}
return OverlayfsTeardownResult::Ok;
}
OverlayfsTeardownResult fs_mgr_overlayfs_teardown_scratch(const std::string& overlay,
bool* change) {
// umount and delete kScratchMountPoint storage if we have logical partitions
if (overlay != kScratchMountPoint) {
return OverlayfsTeardownResult::Ok;
}
// Validation check.
if (fs_mgr_is_dsu_running()) {
LERROR << "Destroying DSU scratch is not allowed.";
return OverlayfsTeardownResult::Error;
}
bool was_mounted = fs_mgr_overlayfs_already_mounted(kScratchMountPoint, false);
if (was_mounted) {
fs_mgr_overlayfs_umount_scratch();
}
const auto partition_name = android::base::Basename(kScratchMountPoint);
auto images = IImageManager::Open("remount", 10s);
if (images && images->BackingImageExists(partition_name)) {
// No need to check super partition, if we knew we had a scratch device
// in /data.
return TeardownDataScratch(images.get(), partition_name, was_mounted);
}
auto slot_number = fs_mgr_overlayfs_slot_number();
const auto super_device = kPhysicalDevice + fs_mgr_get_super_partition_name();
if (access(super_device.c_str(), R_OK | W_OK)) {
return OverlayfsTeardownResult::Ok;
}
auto builder = MetadataBuilder::New(super_device, slot_number);
if (!builder) {
return OverlayfsTeardownResult::Ok;
}
if (builder->FindPartition(partition_name) == nullptr) {
return OverlayfsTeardownResult::Ok;
}
builder->RemovePartition(partition_name);
auto metadata = builder->Export();
if (metadata && UpdatePartitionTable(super_device, *metadata.get(), slot_number)) {
if (change) *change = true;
if (!DestroyLogicalPartition(partition_name)) {
return OverlayfsTeardownResult::Error;
}
} else {
LERROR << "delete partition " << overlay;
return OverlayfsTeardownResult::Error;
}
if (was_mounted) {
return OverlayfsTeardownResult::Busy;
}
return OverlayfsTeardownResult::Ok;
}
bool fs_mgr_overlayfs_teardown_one(const std::string& overlay, const std::string& mount_point,
bool* change, bool* should_destroy_scratch = nullptr) {
const auto top = overlay + "/" + kOverlayTopDir;
if (access(top.c_str(), F_OK)) {
if (should_destroy_scratch) *should_destroy_scratch = true;
return true;
}
auto cleanup_all = mount_point.empty();
const auto partition_name = android::base::Basename(mount_point);
const auto oldpath = top + (cleanup_all ? "" : ("/" + partition_name));
const auto newpath = cleanup_all ? overlay + "/." + kOverlayTopDir + ".teardown"
: top + "/." + partition_name + ".teardown";
auto ret = fs_mgr_rm_all(newpath);
if (!rename(oldpath.c_str(), newpath.c_str())) {
if (change) *change = true;
} else if (errno != ENOENT) {
ret = false;
PERROR << "mv " << oldpath << " " << newpath;
}
ret &= fs_mgr_rm_all(newpath, change);
if (!rmdir(newpath.c_str())) {
if (change) *change = true;
} else if (errno != ENOENT) {
ret = false;
PERROR << "rmdir " << newpath;
}
if (!cleanup_all) {
if (!rmdir(top.c_str())) {
if (change) *change = true;
cleanup_all = true;
} else if (errno == ENOTEMPTY) {
cleanup_all = true;
// cleanup all if the content is all hidden (leading .)
std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(top.c_str()), closedir);
if (!dir) {
PERROR << "opendir " << top;
} else {
dirent* entry;
while ((entry = readdir(dir.get()))) {
if (entry->d_name[0] != '.') {
cleanup_all = false;
break;
}
}
}
} else if (errno == ENOENT) {
cleanup_all = true;
} else {
ret = false;
PERROR << "rmdir " << top;
}
}
if (should_destroy_scratch) *should_destroy_scratch = cleanup_all;
return ret;
}
// Note: The scratch partition of DSU is managed by gsid, and should be initialized during
// first-stage-mount. Just check if the DM device for DSU scratch partition is created or not.
static std::string GetDsuScratchDevice() {
auto& dm = DeviceMapper::Instance();
std::string device;
if (dm.GetState(android::gsi::kDsuScratch) != DmDeviceState::INVALID &&
dm.GetDmDevicePathByName(android::gsi::kDsuScratch, &device)) {
return device;
}
return "";
}
// This returns the scratch device that was detected during early boot (first-
// stage init). If the device was created later, for example during setup for
// the adb remount command, it can return an empty string since it does not
// query ImageManager. (Note that ImageManager in first-stage init will always
// use device-mapper, since /data is not available to use loop devices.)
static std::string GetBootScratchDevice() {
// Note: fs_mgr_is_dsu_running() always returns false in recovery or fastbootd.
if (fs_mgr_is_dsu_running()) {
return GetDsuScratchDevice();
}
auto& dm = DeviceMapper::Instance();
// If there is a scratch partition allocated in /data or on super, we
// automatically prioritize that over super_other or system_other.
// Some devices, for example, have a write-protected eMMC and the
// super partition cannot be used even if it exists.
std::string device;
auto partition_name = android::base::Basename(kScratchMountPoint);
if (dm.GetState(partition_name) != DmDeviceState::INVALID &&
dm.GetDmDevicePathByName(partition_name, &device)) {
return device;
}
return "";
}
bool MakeScratchFilesystem(const std::string& scratch_device) {
// Force mkfs by design for overlay support of adb remount, simplify and
// thus do not rely on fsck to correct problems that could creep in.
auto fs_type = ""s;
auto command = ""s;
if (!access(kMkF2fs, X_OK) && fs_mgr_filesystem_available("f2fs")) {
fs_type = "f2fs";
command = kMkF2fs + " -w "s;
command += std::to_string(getpagesize());
command += " -f -d1 -l" + android::base::Basename(kScratchMountPoint);
} else if (!access(kMkExt4, X_OK) && fs_mgr_filesystem_available("ext4")) {
fs_type = "ext4";
command = kMkExt4 + " -F -b 4096 -t ext4 -m 0 -O has_journal -M "s + kScratchMountPoint;
} else {
LERROR << "No supported mkfs command or filesystem driver available, supported filesystems "
"are: f2fs, ext4";
return false;
}
command += " " + scratch_device + " >/dev/null 2>/dev/null </dev/null";
fs_mgr_set_blk_ro(scratch_device, false);
auto ret = system(command.c_str());
if (ret) {
LERROR << "make " << fs_type << " filesystem on " << scratch_device << " return=" << ret;
return false;
}
return true;
}
static void TruncatePartitionsWithSuffix(MetadataBuilder* builder, const std::string& suffix) {
auto& dm = DeviceMapper::Instance();
// Remove <other> partitions
for (const auto& group : builder->ListGroups()) {
for (const auto& part : builder->ListPartitionsInGroup(group)) {
const auto& name = part->name();
if (!android::base::EndsWith(name, suffix)) {
continue;
}
if (dm.GetState(name) != DmDeviceState::INVALID && !DestroyLogicalPartition(name)) {
continue;
}
builder->ResizePartition(builder->FindPartition(name), 0);
}
}
}
// Create or update a scratch partition within super.
static bool CreateDynamicScratch(std::string* scratch_device, bool* partition_exists) {
const auto partition_name = android::base::Basename(kScratchMountPoint);
auto& dm = DeviceMapper::Instance();
*partition_exists = dm.GetState(partition_name) != DmDeviceState::INVALID;
auto partition_create = !*partition_exists;
auto slot_number = fs_mgr_overlayfs_slot_number();
const auto super_device = kPhysicalDevice + fs_mgr_get_super_partition_name();
auto builder = MetadataBuilder::New(super_device, slot_number);
if (!builder) {
LERROR << "open " << super_device << " metadata";
return false;
}
auto partition = builder->FindPartition(partition_name);
*partition_exists = partition != nullptr;
auto changed = false;
if (!*partition_exists) {
partition = builder->AddPartition(partition_name, LP_PARTITION_ATTR_NONE);
if (!partition) {
LERROR << "create " << partition_name;
return false;
}
changed = true;
}
// Take half of free space, minimum 512MB or maximum free - margin.
static constexpr auto kMinimumSize = uint64_t(512 * 1024 * 1024);
if (partition->size() < kMinimumSize) {
auto partition_size =
builder->AllocatableSpace() - builder->UsedSpace() + partition->size();
if ((partition_size > kMinimumSize) || !partition->size()) {
partition_size = std::max(std::min(kMinimumSize, partition_size), partition_size / 2);
if (partition_size > partition->size()) {
if (!builder->ResizePartition(partition, partition_size)) {
// Try to free up space by deallocating partitions in the other slot.
TruncatePartitionsWithSuffix(builder.get(), fs_mgr_get_other_slot_suffix());
partition_size =
builder->AllocatableSpace() - builder->UsedSpace() + partition->size();
partition_size =
std::max(std::min(kMinimumSize, partition_size), partition_size / 2);
if (!builder->ResizePartition(partition, partition_size)) {
LERROR << "resize " << partition_name;
return false;
}
}
if (!partition_create) DestroyLogicalPartition(partition_name);
changed = true;
*partition_exists = false;
}
}
}
// land the update back on to the partition
if (changed) {
auto metadata = builder->Export();
if (!metadata || !UpdatePartitionTable(super_device, *metadata.get(), slot_number)) {
LERROR << "add partition " << partition_name;
return false;
}
}
if (changed || partition_create) {
CreateLogicalPartitionParams params = {
.block_device = super_device,
.metadata_slot = slot_number,
.partition_name = partition_name,
.force_writable = true,
.timeout_ms = 10s,
};
if (!CreateLogicalPartition(params, scratch_device)) {
return false;
}
} else if (scratch_device->empty()) {
*scratch_device = GetBootScratchDevice();
}
return true;
}
static inline uint64_t GetIdealDataScratchSize() {
BlockDeviceInfo super_info;
PartitionOpener opener;
if (!opener.GetInfo(fs_mgr_get_super_partition_name(), &super_info)) {
LERROR << "could not get block device info for super";
return 0;
}
struct statvfs s;
if (statvfs("/data", &s) < 0) {
PERROR << "could not statfs /data";
return 0;
}
auto ideal_size = std::min(super_info.size, uint64_t(uint64_t(s.f_frsize) * s.f_bfree * 0.85));
// Align up to the filesystem block size.
if (auto remainder = ideal_size % s.f_bsize; remainder > 0) {
ideal_size += s.f_bsize - remainder;
}
return ideal_size;
}
static bool CreateScratchOnData(std::string* scratch_device, bool* partition_exists) {
*partition_exists = false;
auto images = IImageManager::Open("remount", 10s);
if (!images) {
return false;
}
auto partition_name = android::base::Basename(kScratchMountPoint);
if (images->GetMappedImageDevice(partition_name, scratch_device)) {
*partition_exists = true;
return true;
}
// Note: calling RemoveDisabledImages here ensures that we do not race with
// clean_scratch_files and accidentally try to map an image that will be
// deleted.
if (!images->RemoveDisabledImages()) {
return false;
}
if (!images->BackingImageExists(partition_name)) {
auto size = android::base::GetUintProperty<uint64_t>(kDataScratchSizeMbProp, 0) * 1_MiB;
if (!size) {
size = GetIdealDataScratchSize();
}
if (!size) {
size = 2_GiB;
}
auto flags = IImageManager::CREATE_IMAGE_DEFAULT;
if (!images->CreateBackingImage(partition_name, size, flags)) {
LERROR << "could not create scratch image of " << size << " bytes";
return false;
}
}
if (!images->MapImageDevice(partition_name, 10s, scratch_device)) {
LERROR << "could not map scratch image";
// If we cannot use this image, then remove it.
TeardownDataScratch(images.get(), partition_name, false /* was_mounted */);
return false;
}
return true;
}
static bool CanUseSuperPartition(const Fstab& fstab) {
auto slot_number = fs_mgr_overlayfs_slot_number();
const auto super_device = kPhysicalDevice + fs_mgr_get_super_partition_name();
if (access(super_device.c_str(), R_OK | W_OK) || !fs_mgr_overlayfs_has_logical(fstab)) {
return false;
}
auto metadata = ReadMetadata(super_device, slot_number);
if (!metadata) {
return false;
}
return true;
}
bool fs_mgr_overlayfs_create_scratch(const Fstab& fstab, std::string* scratch_device,
bool* partition_exists) {
// Use the DSU scratch device managed by gsid if within a DSU system.
if (fs_mgr_is_dsu_running()) {
*scratch_device = GetDsuScratchDevice();
*partition_exists = !scratch_device->empty();
return *partition_exists;
}
// Try ImageManager on /data first.
bool can_use_data = false;
if (FilesystemHasReliablePinning("/data", &can_use_data) && can_use_data) {
if (CreateScratchOnData(scratch_device, partition_exists)) {
return true;
}
LOG(WARNING) << "Failed to allocate scratch on /data, fallback to use free space on super";
}
// If that fails, see if we can land on super.
if (CanUseSuperPartition(fstab)) {
return CreateDynamicScratch(scratch_device, partition_exists);
}
return false;
}
// Create and mount kScratchMountPoint storage if we have logical partitions
bool fs_mgr_overlayfs_setup_scratch(const Fstab& fstab) {
if (fs_mgr_overlayfs_already_mounted(kScratchMountPoint, false)) {
return true;
}
std::string scratch_device;
bool partition_exists;
if (!fs_mgr_overlayfs_create_scratch(fstab, &scratch_device, &partition_exists)) {
LOG(ERROR) << "Failed to create scratch partition";
return false;
}
// If the partition exists, assume first that it can be mounted.
if (partition_exists) {
if (MountScratch(scratch_device)) {
const auto top = kScratchMountPoint + "/"s + kOverlayTopDir;
if (access(top.c_str(), F_OK) == 0 || fs_mgr_filesystem_has_space(kScratchMountPoint)) {
return true;
}
// declare it useless, no overrides and no free space
if (!fs_mgr_overlayfs_umount_scratch()) {
LOG(ERROR) << "Unable to unmount scratch partition";
return false;
}
}
}
if (!MakeScratchFilesystem(scratch_device)) {
LOG(ERROR) << "Failed to format scratch partition";
return false;
}
return MountScratch(scratch_device);
}
constexpr bool OverlayfsTeardownAllowed() {
// Never allow on non-debuggable build.
return kAllowOverlayfs;
}
} // namespace
bool fs_mgr_overlayfs_setup(const Fstab& fstab, const char* mount_point, bool* want_reboot,
bool just_disabled_verity) {
if (!OverlayfsSetupAllowed(/*verbose=*/true)) {
return false;
}
if (!fs_mgr_boot_completed()) {
LOG(ERROR) << "Cannot setup overlayfs before persistent properties are ready";
return false;
}
auto candidates = fs_mgr_overlayfs_candidate_list(fstab);
for (auto it = candidates.begin(); it != candidates.end();) {
if (mount_point &&
(fs_mgr_mount_point(it->mount_point) != fs_mgr_mount_point(mount_point))) {
it = candidates.erase(it);
continue;
}
auto verity_enabled = !just_disabled_verity && fs_mgr_is_verity_enabled(*it);
if (verity_enabled) {
it = candidates.erase(it);
continue;
}
++it;
}
if (candidates.empty()) {
if (mount_point) {
LOG(ERROR) << "No overlayfs candidate was found for " << mount_point;
return false;
}
return true;
}
std::string dir;
for (const auto& overlay_mount_point : OverlayMountPoints()) {
if (overlay_mount_point == kScratchMountPoint) {
if (!fs_mgr_overlayfs_setup_scratch(fstab)) {
continue;
}
} else {
if (!fs_mgr_overlayfs_already_mounted(overlay_mount_point, false /* overlay */)) {
continue;
}
}
dir = overlay_mount_point;
break;
}
if (dir.empty()) {
LOG(ERROR) << "Could not allocate backing storage for overlays";
return false;
}
const auto overlay = fs_mgr_overlayfs_setup_dir(dir);
if (overlay.empty()) {
return false;
}
bool ok = true;
for (const auto& entry : candidates) {
auto fstab_mount_point = fs_mgr_mount_point(entry.mount_point);
ok &= fs_mgr_overlayfs_setup_one(overlay, fstab_mount_point, want_reboot);
}
return ok;
}
struct MapInfo {
// If set, partition is owned by ImageManager.
std::unique_ptr<IImageManager> images;
// If set, and images is null, this is a DAP partition.
std::string name;
// If set, and images and name are empty, this is a non-dynamic partition.
std::string device;
MapInfo() = default;
MapInfo(MapInfo&&) = default;
~MapInfo() {
if (images) {
images->UnmapImageDevice(name);
} else if (!name.empty()) {
DestroyLogicalPartition(name);
}
}
};
// Note: This function never returns the DSU scratch device in recovery or fastbootd,
// because the DSU scratch is created in the first-stage-mount, which is not run in recovery.
static std::optional<MapInfo> EnsureScratchMapped() {
MapInfo info;
info.device = GetBootScratchDevice();
if (!info.device.empty()) {
return {std::move(info)};
}
if (!InRecovery()) {
return {};
}
auto partition_name = android::base::Basename(kScratchMountPoint);
// Check for scratch on /data first, before looking for a modified super
// partition. We should only reach this code in recovery, because scratch
// would otherwise always be mapped.
auto images = IImageManager::Open("remount", 10s);
if (images && images->BackingImageExists(partition_name)) {
if (images->IsImageDisabled(partition_name)) {
return {};
}
if (!images->MapImageDevice(partition_name, 10s, &info.device)) {
return {};
}
info.name = partition_name;
info.images = std::move(images);
return {std::move(info)};
}
// Avoid uart spam by first checking for a scratch partition.
const auto super_device = kPhysicalDevice + fs_mgr_get_super_partition_name();
auto metadata = ReadCurrentMetadata(super_device);
if (!metadata) {
return {};
}
auto partition = FindPartition(*metadata.get(), partition_name);
if (!partition) {
return {};
}
CreateLogicalPartitionParams params = {
.block_device = super_device,
.metadata = metadata.get(),
.partition = partition,
.force_writable = true,
.timeout_ms = 10s,
};
if (!CreateLogicalPartition(params, &info.device)) {
return {};
}
info.name = partition_name;
return {std::move(info)};
}
// This should only be reachable in recovery, where DSU scratch is not
// automatically mapped.
static bool MapDsuScratchDevice(std::string* device) {
std::string dsu_slot;
if (!android::gsi::IsGsiInstalled() || !android::gsi::GetActiveDsu(&dsu_slot) ||
dsu_slot.empty()) {
// Nothing to do if no DSU installation present.
return false;
}
auto images = IImageManager::Open("dsu/" + dsu_slot, 10s);
if (!images || !images->BackingImageExists(android::gsi::kDsuScratch)) {
// Nothing to do if DSU scratch device doesn't exist.
return false;
}
images->UnmapImageDevice(android::gsi::kDsuScratch);
if (!images->MapImageDevice(android::gsi::kDsuScratch, 10s, device)) {
return false;
}
return true;
}
static OverlayfsTeardownResult TeardownMountsAndScratch(const char* mount_point,
bool* want_reboot) {
bool should_destroy_scratch = false;
auto rv = OverlayfsTeardownResult::Ok;
for (const auto& overlay_mount_point : OverlayMountPoints()) {
auto ok = fs_mgr_overlayfs_teardown_one(
overlay_mount_point, mount_point ? fs_mgr_mount_point(mount_point) : "",
want_reboot,
overlay_mount_point == kScratchMountPoint ? &should_destroy_scratch : nullptr);
if (!ok) {
rv = OverlayfsTeardownResult::Error;
}
}
// Do not attempt to destroy DSU scratch if within a DSU system,
// because DSU scratch partition is managed by gsid.
if (should_destroy_scratch && !fs_mgr_is_dsu_running()) {
auto rv = fs_mgr_overlayfs_teardown_scratch(kScratchMountPoint, want_reboot);
if (rv != OverlayfsTeardownResult::Ok) {
return rv;
}
}
// And now that we did what we could, lets inform
// caller that there may still be more to do.
if (!fs_mgr_boot_completed()) {
LOG(ERROR) << "Cannot teardown overlayfs before persistent properties are ready";
return OverlayfsTeardownResult::Error;
}
return rv;
}
// Returns false if teardown not permitted. If something is altered, set *want_reboot.
OverlayfsTeardownResult fs_mgr_overlayfs_teardown(const char* mount_point, bool* want_reboot) {
if (!OverlayfsTeardownAllowed()) {
// Nothing to teardown.
return OverlayfsTeardownResult::Ok;
}
// If scratch exists, but is not mounted, lets gain access to clean
// specific override entries.
auto mount_scratch = false;
if ((mount_point != nullptr) && !fs_mgr_overlayfs_already_mounted(kScratchMountPoint, false)) {
std::string scratch_device = GetBootScratchDevice();
if (!scratch_device.empty()) {
mount_scratch = MountScratch(scratch_device);
}
}
auto rv = TeardownMountsAndScratch(mount_point, want_reboot);
if (mount_scratch) {
if (!fs_mgr_overlayfs_umount_scratch()) {
return OverlayfsTeardownResult::Busy;
}
}
return rv;
}
namespace android {
namespace fs_mgr {
void MapScratchPartitionIfNeeded(Fstab* fstab,
const std::function<bool(const std::set<std::string>&)>& init) {
if (!OverlayfsSetupAllowed()) {
return;
}
if (GetEntryForMountPoint(fstab, kScratchMountPoint) != nullptr) {
return;
}
bool want_scratch = false;
for (const auto& entry : fs_mgr_overlayfs_candidate_list(*fstab)) {
if (fs_mgr_is_verity_enabled(entry)) {
continue;
}
if (fs_mgr_overlayfs_already_mounted(fs_mgr_mount_point(entry.mount_point))) {
continue;
}
want_scratch = true;
break;
}
if (!want_scratch) {
return;
}
if (ScratchIsOnData()) {
if (auto images = IImageManager::Open("remount", 0ms)) {
images->MapAllImages(init);
}
}
// Physical or logical partitions will have already been mapped here,
// so just ensure /dev/block symlinks exist.
auto device = GetBootScratchDevice();
if (!device.empty()) {
init({android::base::Basename(device)});
}
}
void CleanupOldScratchFiles() {
if (!OverlayfsTeardownAllowed()) {
return;
}
if (!ScratchIsOnData()) {
return;
}
if (auto images = IImageManager::Open("remount", 0ms)) {
images->RemoveDisabledImages();
}
}
void TeardownAllOverlayForMountPoint(const std::string& mount_point) {
if (!OverlayfsTeardownAllowed()) {
return;
}
if (!InRecovery()) {
LERROR << __FUNCTION__ << "(): must be called within recovery.";
return;
}
// Empty string means teardown everything.
const std::string teardown_dir = mount_point.empty() ? "" : fs_mgr_mount_point(mount_point);
constexpr bool* ignore_change = nullptr;
// Teardown legacy overlay mount points that's not backed by a scratch device.
for (const auto& overlay_mount_point : OverlayMountPoints()) {
if (overlay_mount_point == kScratchMountPoint) {
continue;
}
fs_mgr_overlayfs_teardown_one(overlay_mount_point, teardown_dir, ignore_change);
}
if (mount_point.empty()) {
// Throw away the entire partition.
auto partition_name = android::base::Basename(kScratchMountPoint);
auto images = IImageManager::Open("remount", 10s);
if (images && images->BackingImageExists(partition_name)) {
if (images->DisableImage(partition_name)) {
LOG(INFO) << "Disabled scratch partition for: " << kScratchMountPoint;
} else {
LOG(ERROR) << "Unable to disable scratch partition for " << kScratchMountPoint;
}
}
}
// Note if we just disabled scratch, this mount will fail.
if (auto info = EnsureScratchMapped(); info.has_value()) {
// Map scratch device, mount kScratchMountPoint and teardown kScratchMountPoint.
fs_mgr_overlayfs_umount_scratch();
if (MountScratch(info->device)) {
bool should_destroy_scratch = false;
fs_mgr_overlayfs_teardown_one(kScratchMountPoint, teardown_dir, ignore_change,
&should_destroy_scratch);
fs_mgr_overlayfs_umount_scratch();
if (should_destroy_scratch) {
fs_mgr_overlayfs_teardown_scratch(kScratchMountPoint, nullptr);
}
}
}
// Teardown DSU overlay if present.
std::string scratch_device;
if (MapDsuScratchDevice(&scratch_device)) {
fs_mgr_overlayfs_umount_scratch();
if (MountScratch(scratch_device)) {
fs_mgr_overlayfs_teardown_one(kScratchMountPoint, teardown_dir, ignore_change);
fs_mgr_overlayfs_umount_scratch();
}
DestroyLogicalPartition(android::gsi::kDsuScratch);
}
}
} // namespace fs_mgr
} // namespace android