a688c4f1b2
Allows for easy override of fuse-bpf for testing without a rebuild
Test: Set this property with ro.fuse.bpf.enabled both true and false
Make sure ro.fuse.bpf.is_running is expected result
Bug: 219958836
Change-Id: I589511ea5cda76db1d55bdc2124fb546907d8acd
531 lines
20 KiB
C++
531 lines
20 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "EmulatedVolume.h"
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#include "AppFuseUtil.h"
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#include "Utils.h"
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#include "VolumeBase.h"
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#include "VolumeManager.h"
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#include <android-base/logging.h>
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#include <android-base/properties.h>
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#include <android-base/scopeguard.h>
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#include <android-base/stringprintf.h>
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#include <cutils/fs.h>
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#include <private/android_filesystem_config.h>
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#include <utils/Timers.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <sys/mount.h>
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#include <sys/stat.h>
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#include <sys/sysmacros.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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using android::base::StringPrintf;
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namespace android {
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namespace vold {
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static const char* kSdcardFsPath = "/system/bin/sdcard";
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EmulatedVolume::EmulatedVolume(const std::string& rawPath, int userId)
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: VolumeBase(Type::kEmulated) {
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setId(StringPrintf("emulated;%u", userId));
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mRawPath = rawPath;
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mLabel = "emulated";
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mFuseMounted = false;
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mUseSdcardFs = IsSdcardfsUsed();
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mAppDataIsolationEnabled = base::GetBoolProperty(kVoldAppDataIsolationEnabled, false);
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}
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EmulatedVolume::EmulatedVolume(const std::string& rawPath, dev_t device, const std::string& fsUuid,
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int userId)
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: VolumeBase(Type::kEmulated) {
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setId(StringPrintf("emulated:%u,%u;%u", major(device), minor(device), userId));
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mRawPath = rawPath;
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mLabel = fsUuid;
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mFuseMounted = false;
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mUseSdcardFs = IsSdcardfsUsed();
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mAppDataIsolationEnabled = base::GetBoolProperty(kVoldAppDataIsolationEnabled, false);
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}
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EmulatedVolume::~EmulatedVolume() {}
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std::string EmulatedVolume::getLabel() const {
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// We could have migrated storage to an adopted private volume, so always
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// call primary storage "emulated" to avoid media rescans.
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if (getMountFlags() & MountFlags::kPrimary) {
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return "emulated";
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} else {
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return mLabel;
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}
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}
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// Creates a bind mount from source to target
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static status_t doFuseBindMount(const std::string& source, const std::string& target,
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std::list<std::string>& pathsToUnmount) {
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LOG(INFO) << "Bind mounting " << source << " on " << target;
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auto status = BindMount(source, target);
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if (status != OK) {
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return status;
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}
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LOG(INFO) << "Bind mounted " << source << " on " << target;
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pathsToUnmount.push_front(target);
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return OK;
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}
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// Bind mounts the volume 'volume' onto this volume.
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status_t EmulatedVolume::bindMountVolume(const EmulatedVolume& volume,
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std::list<std::string>& pathsToUnmount) {
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int myUserId = getMountUserId();
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int volumeUserId = volume.getMountUserId();
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std::string label = volume.getLabel();
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// eg /mnt/user/10/emulated/10
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std::string srcUserPath = GetFuseMountPathForUser(volumeUserId, label);
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std::string srcPath = StringPrintf("%s/%d", srcUserPath.c_str(), volumeUserId);
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// eg /mnt/user/0/emulated/10
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std::string dstUserPath = GetFuseMountPathForUser(myUserId, label);
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std::string dstPath = StringPrintf("%s/%d", dstUserPath.c_str(), volumeUserId);
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auto status = doFuseBindMount(srcPath, dstPath, pathsToUnmount);
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if (status == OK) {
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// Store the mount path, so we can unmount it when this volume goes away
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mSharedStorageMountPath = dstPath;
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}
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return status;
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}
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status_t EmulatedVolume::mountFuseBindMounts() {
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std::string androidSource;
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std::string label = getLabel();
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int userId = getMountUserId();
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std::list<std::string> pathsToUnmount;
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auto unmounter = [&]() {
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LOG(INFO) << "mountFuseBindMounts() unmount scope_guard running";
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for (const auto& path : pathsToUnmount) {
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LOG(INFO) << "Unmounting " << path;
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auto status = UnmountTree(path);
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if (status != OK) {
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LOG(INFO) << "Failed to unmount " << path;
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} else {
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LOG(INFO) << "Unmounted " << path;
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}
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}
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};
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auto unmount_guard = android::base::make_scope_guard(unmounter);
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if (mUseSdcardFs) {
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androidSource = StringPrintf("/mnt/runtime/default/%s/%d/Android", label.c_str(), userId);
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} else {
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androidSource = StringPrintf("/%s/%d/Android", mRawPath.c_str(), userId);
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}
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status_t status = OK;
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// Zygote will unmount these dirs if app data isolation is enabled, so apps
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// cannot access these dirs directly.
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std::string androidDataSource = StringPrintf("%s/data", androidSource.c_str());
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std::string androidDataTarget(
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StringPrintf("/mnt/user/%d/%s/%d/Android/data", userId, label.c_str(), userId));
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status = doFuseBindMount(androidDataSource, androidDataTarget, pathsToUnmount);
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if (status != OK) {
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return status;
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}
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std::string androidObbSource = StringPrintf("%s/obb", androidSource.c_str());
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std::string androidObbTarget(
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StringPrintf("/mnt/user/%d/%s/%d/Android/obb", userId, label.c_str(), userId));
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status = doFuseBindMount(androidObbSource, androidObbTarget, pathsToUnmount);
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if (status != OK) {
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return status;
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}
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// Installers get the same view as all other apps, with the sole exception that the
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// OBB dirs (Android/obb) are writable to them. On sdcardfs devices, this requires
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// a special bind mount, since app-private and OBB dirs share the same GID, but we
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// only want to give access to the latter.
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if (mUseSdcardFs) {
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std::string obbSource(StringPrintf("/mnt/runtime/write/%s/%d/Android/obb",
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label.c_str(), userId));
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std::string obbInstallerTarget(StringPrintf("/mnt/installer/%d/%s/%d/Android/obb",
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userId, label.c_str(), userId));
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status = doFuseBindMount(obbSource, obbInstallerTarget, pathsToUnmount);
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if (status != OK) {
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return status;
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}
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}
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// For users that share their volume with another user (eg a clone
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// profile), the current mount setup can cause page cache inconsistency
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// issues. Let's say this is user 10, and the user it shares storage with
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// is user 0.
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// Then:
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// * The FUSE daemon for user 0 serves /mnt/user/0
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// * The FUSE daemon for user 10 serves /mnt/user/10
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// The emulated volume for user 10 would be located at two paths:
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// /mnt/user/0/emulated/10
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// /mnt/user/10/emulated/10
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// Since these paths refer to the same files but are served by different FUSE
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// daemons, this can result in page cache inconsistency issues. To prevent this,
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// bind mount the relevant paths for the involved users:
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// 1. /mnt/user/10/emulated/10 =B=> /mnt/user/0/emulated/10
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// 2. /mnt/user/0/emulated/0 =B=> /mnt/user/10/emulated/0
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//
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// This will ensure that any access to the volume for a specific user always
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// goes through a single FUSE daemon.
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userid_t sharedStorageUserId = VolumeManager::Instance()->getSharedStorageUser(userId);
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if (sharedStorageUserId != USER_UNKNOWN) {
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auto filter_fn = [&](const VolumeBase& vol) {
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if (vol.getState() != VolumeBase::State::kMounted) {
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// The volume must be mounted
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return false;
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}
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if (vol.getType() != VolumeBase::Type::kEmulated) {
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return false;
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}
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if (vol.getMountUserId() != sharedStorageUserId) {
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return false;
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}
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if ((vol.getMountFlags() & MountFlags::kPrimary) == 0) {
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// We only care about the primary emulated volume, so not a private
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// volume with an emulated volume stacked on top.
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return false;
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}
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return true;
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};
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auto vol = VolumeManager::Instance()->findVolumeWithFilter(filter_fn);
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if (vol != nullptr) {
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auto sharedVol = static_cast<EmulatedVolume*>(vol.get());
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// Bind mount this volume in the other user's primary volume
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status = sharedVol->bindMountVolume(*this, pathsToUnmount);
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if (status != OK) {
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return status;
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}
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// And vice-versa
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status = bindMountVolume(*sharedVol, pathsToUnmount);
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if (status != OK) {
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return status;
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}
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}
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}
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unmount_guard.Disable();
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return OK;
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}
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status_t EmulatedVolume::unmountFuseBindMounts() {
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std::string label = getLabel();
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int userId = getMountUserId();
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if (!mSharedStorageMountPath.empty()) {
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LOG(INFO) << "Unmounting " << mSharedStorageMountPath;
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auto status = UnmountTree(mSharedStorageMountPath);
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if (status != OK) {
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LOG(ERROR) << "Failed to unmount " << mSharedStorageMountPath;
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}
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mSharedStorageMountPath = "";
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}
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if (mUseSdcardFs || mAppDataIsolationEnabled) {
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std::string installerTarget(
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StringPrintf("/mnt/installer/%d/%s/%d/Android/obb", userId, label.c_str(), userId));
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LOG(INFO) << "Unmounting " << installerTarget;
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auto status = UnmountTree(installerTarget);
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if (status != OK) {
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LOG(ERROR) << "Failed to unmount " << installerTarget;
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// Intentional continue to try to unmount the other bind mount
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}
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}
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if (mAppDataIsolationEnabled) {
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std::string obbTarget( StringPrintf("/mnt/androidwritable/%d/%s/%d/Android/obb",
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userId, label.c_str(), userId));
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LOG(INFO) << "Unmounting " << obbTarget;
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auto status = UnmountTree(obbTarget);
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if (status != OK) {
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LOG(ERROR) << "Failed to unmount " << obbTarget;
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// Intentional continue to try to unmount the other bind mount
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}
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std::string dataTarget(StringPrintf("/mnt/androidwritable/%d/%s/%d/Android/data",
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userId, label.c_str(), userId));
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LOG(INFO) << "Unmounting " << dataTarget;
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status = UnmountTree(dataTarget);
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if (status != OK) {
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LOG(ERROR) << "Failed to unmount " << dataTarget;
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// Intentional continue to try to unmount the other bind mount
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}
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}
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// When app data isolation is enabled, kill all apps that obb/ is mounted, otherwise we should
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// umount the whole Android/ dir.
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if (mAppDataIsolationEnabled) {
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std::string appObbDir(StringPrintf("%s/%d/Android/obb", getPath().c_str(), userId));
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// Here we assume obb/data dirs is mounted as tmpfs, then it must be caused by
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// app data isolation.
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KillProcessesWithTmpfsMountPrefix(appObbDir);
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}
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// Always unmount data and obb dirs as they are mounted to lowerfs for speeding up access.
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std::string androidDataTarget(
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StringPrintf("/mnt/user/%d/%s/%d/Android/data", userId, label.c_str(), userId));
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LOG(INFO) << "Unmounting " << androidDataTarget;
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auto status = UnmountTree(androidDataTarget);
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if (status != OK) {
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return status;
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}
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LOG(INFO) << "Unmounted " << androidDataTarget;
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std::string androidObbTarget(
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StringPrintf("/mnt/user/%d/%s/%d/Android/obb", userId, label.c_str(), userId));
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LOG(INFO) << "Unmounting " << androidObbTarget;
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status = UnmountTree(androidObbTarget);
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if (status != OK) {
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return status;
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}
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LOG(INFO) << "Unmounted " << androidObbTarget;
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return OK;
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}
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status_t EmulatedVolume::unmountSdcardFs() {
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if (!mUseSdcardFs || getMountUserId() != 0) {
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// For sdcardfs, only unmount for user 0, since user 0 will always be running
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// and the paths don't change for different users.
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return OK;
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}
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ForceUnmount(mSdcardFsDefault);
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ForceUnmount(mSdcardFsRead);
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ForceUnmount(mSdcardFsWrite);
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ForceUnmount(mSdcardFsFull);
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rmdir(mSdcardFsDefault.c_str());
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rmdir(mSdcardFsRead.c_str());
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rmdir(mSdcardFsWrite.c_str());
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rmdir(mSdcardFsFull.c_str());
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mSdcardFsDefault.clear();
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mSdcardFsRead.clear();
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mSdcardFsWrite.clear();
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mSdcardFsFull.clear();
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return OK;
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}
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status_t EmulatedVolume::doMount() {
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std::string label = getLabel();
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bool isVisible = isVisibleForWrite();
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mSdcardFsDefault = StringPrintf("/mnt/runtime/default/%s", label.c_str());
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mSdcardFsRead = StringPrintf("/mnt/runtime/read/%s", label.c_str());
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mSdcardFsWrite = StringPrintf("/mnt/runtime/write/%s", label.c_str());
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mSdcardFsFull = StringPrintf("/mnt/runtime/full/%s", label.c_str());
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setInternalPath(mRawPath);
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setPath(StringPrintf("/storage/%s", label.c_str()));
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if (fs_prepare_dir(mSdcardFsDefault.c_str(), 0700, AID_ROOT, AID_ROOT) ||
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fs_prepare_dir(mSdcardFsRead.c_str(), 0700, AID_ROOT, AID_ROOT) ||
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fs_prepare_dir(mSdcardFsWrite.c_str(), 0700, AID_ROOT, AID_ROOT) ||
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fs_prepare_dir(mSdcardFsFull.c_str(), 0700, AID_ROOT, AID_ROOT)) {
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PLOG(ERROR) << getId() << " failed to create mount points";
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return -errno;
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}
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dev_t before = GetDevice(mSdcardFsFull);
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// Mount sdcardfs regardless of FUSE, since we need it to bind-mount on top of the
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// FUSE volume for various reasons.
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if (mUseSdcardFs && getMountUserId() == 0) {
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LOG(INFO) << "Executing sdcardfs";
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int sdcardFsPid;
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if (!(sdcardFsPid = fork())) {
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// clang-format off
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if (execl(kSdcardFsPath, kSdcardFsPath,
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"-u", "1023", // AID_MEDIA_RW
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"-g", "1023", // AID_MEDIA_RW
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"-m",
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"-w",
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"-G",
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"-i",
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"-o",
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mRawPath.c_str(),
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label.c_str(),
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NULL)) {
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// clang-format on
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PLOG(ERROR) << "Failed to exec";
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}
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LOG(ERROR) << "sdcardfs exiting";
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_exit(1);
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}
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if (sdcardFsPid == -1) {
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PLOG(ERROR) << getId() << " failed to fork";
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return -errno;
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}
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nsecs_t start = systemTime(SYSTEM_TIME_BOOTTIME);
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while (before == GetDevice(mSdcardFsFull)) {
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LOG(DEBUG) << "Waiting for sdcardfs to spin up...";
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usleep(50000); // 50ms
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nsecs_t now = systemTime(SYSTEM_TIME_BOOTTIME);
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if (nanoseconds_to_milliseconds(now - start) > 5000) {
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LOG(WARNING) << "Timed out while waiting for sdcardfs to spin up";
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return -ETIMEDOUT;
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}
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}
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/* sdcardfs will have exited already. The filesystem will still be running */
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TEMP_FAILURE_RETRY(waitpid(sdcardFsPid, nullptr, 0));
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sdcardFsPid = 0;
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}
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if (isVisible) {
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// Make sure we unmount sdcardfs if we bail out with an error below
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auto sdcardfs_unmounter = [&]() {
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LOG(INFO) << "sdcardfs_unmounter scope_guard running";
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unmountSdcardFs();
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};
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auto sdcardfs_guard = android::base::make_scope_guard(sdcardfs_unmounter);
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LOG(INFO) << "Mounting emulated fuse volume";
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android::base::unique_fd fd;
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int user_id = getMountUserId();
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auto volumeRoot = getRootPath();
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// Make sure Android/ dirs exist for bind mounting
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status_t res = PrepareAndroidDirs(volumeRoot);
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if (res != OK) {
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LOG(ERROR) << "Failed to prepare Android/ directories";
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return res;
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}
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res = MountUserFuse(user_id, getInternalPath(), label, &fd);
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if (res != 0) {
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PLOG(ERROR) << "Failed to mount emulated fuse volume";
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return res;
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}
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mFuseMounted = true;
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auto fuse_unmounter = [&]() {
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LOG(INFO) << "fuse_unmounter scope_guard running";
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fd.reset();
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if (UnmountUserFuse(user_id, getInternalPath(), label) != OK) {
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PLOG(INFO) << "UnmountUserFuse failed on emulated fuse volume";
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}
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mFuseMounted = false;
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};
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auto fuse_guard = android::base::make_scope_guard(fuse_unmounter);
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auto callback = getMountCallback();
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if (callback) {
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bool is_ready = false;
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callback->onVolumeChecking(std::move(fd), getPath(), getInternalPath(), &is_ready);
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if (!is_ready) {
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return -EIO;
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}
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}
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if (!IsFuseBpfEnabled()) {
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// Only do the bind-mounts when we know for sure the FUSE daemon can resolve the path.
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res = mountFuseBindMounts();
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if (res != OK) {
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return res;
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}
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}
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ConfigureReadAheadForFuse(GetFuseMountPathForUser(user_id, label), 256u);
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// By default, FUSE has a max_dirty ratio of 1%. This means that out of
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// all dirty pages in the system, only 1% is allowed to belong to any
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// FUSE filesystem. The reason this is in place is that FUSE
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// filesystems shouldn't be trusted by default; a FUSE filesystem could
|
|
// take up say 100% of dirty pages, and subsequently refuse to write
|
|
// them back to storage. The kernel will then apply rate-limiting, and
|
|
// block other tasks from writing. For this particular FUSE filesystem
|
|
// however, we trust the implementation, because it is a part of the
|
|
// Android platform. So use the default ratio of 100%.
|
|
//
|
|
// The reason we're setting this is that there's a suspicion that the
|
|
// kernel starts rate-limiting the FUSE filesystem under extreme
|
|
// memory pressure scenarios. While the kernel will only rate limit if
|
|
// the writeback can't keep up with the write rate, under extreme
|
|
// memory pressure the write rate may dip as well, in which case FUSE
|
|
// writes to a 1% max_ratio filesystem are throttled to an extreme amount.
|
|
//
|
|
// To prevent this, just give FUSE 40% max_ratio, meaning it can take
|
|
// up to 40% of all dirty pages in the system.
|
|
ConfigureMaxDirtyRatioForFuse(GetFuseMountPathForUser(user_id, label), 40u);
|
|
|
|
// All mounts where successful, disable scope guards
|
|
sdcardfs_guard.Disable();
|
|
fuse_guard.Disable();
|
|
}
|
|
|
|
return OK;
|
|
}
|
|
|
|
status_t EmulatedVolume::doUnmount() {
|
|
int userId = getMountUserId();
|
|
|
|
// Kill all processes using the filesystem before we unmount it. If we
|
|
// unmount the filesystem 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.
|
|
if (mFuseMounted) {
|
|
// For FUSE specifically, we have an emulated volume per user, so only kill
|
|
// processes using files from this particular user.
|
|
std::string user_path(StringPrintf("%s/%d", getPath().c_str(), getMountUserId()));
|
|
LOG(INFO) << "Killing all processes referencing " << user_path;
|
|
KillProcessesUsingPath(user_path);
|
|
} else {
|
|
KillProcessesUsingPath(getPath());
|
|
}
|
|
|
|
if (mFuseMounted) {
|
|
std::string label = getLabel();
|
|
|
|
if (!IsFuseBpfEnabled()) {
|
|
// Ignoring unmount return status because we do want to try to
|
|
// unmount the rest cleanly.
|
|
unmountFuseBindMounts();
|
|
}
|
|
|
|
if (UnmountUserFuse(userId, getInternalPath(), label) != OK) {
|
|
PLOG(INFO) << "UnmountUserFuse failed on emulated fuse volume";
|
|
return -errno;
|
|
}
|
|
|
|
mFuseMounted = false;
|
|
}
|
|
|
|
return unmountSdcardFs();
|
|
}
|
|
|
|
std::string EmulatedVolume::getRootPath() const {
|
|
int user_id = getMountUserId();
|
|
std::string volumeRoot = StringPrintf("%s/%d", getInternalPath().c_str(), user_id);
|
|
|
|
return volumeRoot;
|
|
}
|
|
|
|
} // namespace vold
|
|
} // namespace android
|