583ae3e55d
persist.sys.fuse.bpf.enable and ro.fuse.bpf.enabled are both used to decide if FUSE-BPF must be enabled or not. - ro.fuse.bpf.enabled is a read-only property that is set in the device makefile and would allow dogfooding devices to turn the feature on/off. - persist.sys.fuse.bpf.enable is a system property that overrides ro.fuse.bpf.enabled and can only be set manually during the development to simplify the testing of FUSE-BPF, mostly to compare if those tests that are failing with FUSE-BPF were failing also without the feature. Bug: 202785178 Test: adb logcat | grep "FuseDaemon" | grep BPF Ignore-AOSP-First: FUSE-BPF is not available in AOSP Signed-off-by: Alessio Balsini <balsini@google.com> Change-Id: I23f9d27172907f6c72c73bea22e4a7e0ac643888
448 lines
16 KiB
C++
448 lines
16 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 "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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mFuseBpfEnabled = IsFuseBpfEnabled();
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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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mFuseBpfEnabled = IsFuseBpfEnabled();
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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() {
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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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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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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 (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 (!mFuseBpfEnabled) {
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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
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// take up say 100% of dirty pages, and subsequently refuse to write
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// them back to storage. The kernel will then apply rate-limiting, and
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// block other tasks from writing. For this particular FUSE filesystem
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// however, we trust the implementation, because it is a part of the
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// Android platform. So use the default ratio of 100%.
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//
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// The reason we're setting this is that there's a suspicion that the
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// kernel starts rate-limiting the FUSE filesystem under extreme
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// memory pressure scenarios. While the kernel will only rate limit if
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// the writeback can't keep up with the write rate, under extreme
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// memory pressure the write rate may dip as well, in which case FUSE
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// writes to a 1% max_ratio filesystem are throttled to an extreme amount.
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//
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// To prevent this, just give FUSE 40% max_ratio, meaning it can take
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// up to 40% of all dirty pages in the system.
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ConfigureMaxDirtyRatioForFuse(GetFuseMountPathForUser(user_id, label), 40u);
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// All mounts where successful, disable scope guards
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sdcardfs_guard.Disable();
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fuse_guard.Disable();
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}
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return OK;
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}
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status_t EmulatedVolume::doUnmount() {
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int userId = getMountUserId();
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// Kill all processes using the filesystem before we unmount it. If we
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// unmount the filesystem first, most file system operations will return
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// ENOTCONN until the unmount completes. This is an exotic and unusual
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// error code and might cause broken behaviour in applications.
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if (mFuseMounted) {
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// For FUSE specifically, we have an emulated volume per user, so only kill
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// processes using files from this particular user.
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std::string user_path(StringPrintf("%s/%d", getPath().c_str(), getMountUserId()));
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LOG(INFO) << "Killing all processes referencing " << user_path;
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KillProcessesUsingPath(user_path);
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} else {
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KillProcessesUsingPath(getPath());
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}
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if (mFuseMounted) {
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std::string label = getLabel();
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if (!mFuseBpfEnabled) {
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// Ignoring unmount return status because we do want to try to
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// unmount the rest cleanly.
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unmountFuseBindMounts();
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}
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if (UnmountUserFuse(userId, getInternalPath(), label) != OK) {
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PLOG(INFO) << "UnmountUserFuse failed on emulated fuse volume";
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return -errno;
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}
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mFuseMounted = false;
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}
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return unmountSdcardFs();
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}
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std::string EmulatedVolume::getRootPath() const {
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int user_id = getMountUserId();
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std::string volumeRoot = StringPrintf("%s/%d", getInternalPath().c_str(), user_id);
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return volumeRoot;
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}
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} // namespace vold
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} // namespace android
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