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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "EmulatedVolume.h"
#include "Utils.h"
#include <android-base/stringprintf.h>
#include <android-base/logging.h>
#include <cutils/fs.h>
#include <private/android_filesystem_config.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/wait.h>
using android::base::StringPrintf;
namespace android {
namespace vold {
static const char* kFusePath = "/system/bin/sdcard";
EmulatedVolume::EmulatedVolume(const std::string& rawPath) :
VolumeBase(Type::kEmulated), mFusePid(0) {
setId("emulated");
mRawPath = rawPath;
mLabel = "emulated";
}
EmulatedVolume::EmulatedVolume(const std::string& rawPath, dev_t device,
const std::string& fsUuid) : VolumeBase(Type::kEmulated), mFusePid(0) {
setId(StringPrintf("emulated:%u,%u", major(device), minor(device)));
mRawPath = rawPath;
mLabel = fsUuid;
}
EmulatedVolume::~EmulatedVolume() {
}
status_t EmulatedVolume::doMount() {
// We could have migrated storage to an adopted private volume, so always
// call primary storage "emulated" to avoid media rescans.
std::string label = mLabel;
if (getMountFlags() & MountFlags::kPrimary) {
label = "emulated";
}
mFuseDefault = StringPrintf("/mnt/runtime/default/%s", label.c_str());
mFuseRead = StringPrintf("/mnt/runtime/read/%s", label.c_str());
mFuseWrite = StringPrintf("/mnt/runtime/write/%s", label.c_str());
setInternalPath(mRawPath);
setPath(StringPrintf("/storage/%s", label.c_str()));
if (fs_prepare_dir(mFuseDefault.c_str(), 0700, AID_ROOT, AID_ROOT) ||
fs_prepare_dir(mFuseRead.c_str(), 0700, AID_ROOT, AID_ROOT) ||
fs_prepare_dir(mFuseWrite.c_str(), 0700, AID_ROOT, AID_ROOT)) {
PLOG(ERROR) << getId() << " failed to create mount points";
return -errno;
}
dev_t before = GetDevice(mFuseWrite);
if (!(mFusePid = fork())) {
if (execl(kFusePath, kFusePath,
"-u", "1023", // AID_MEDIA_RW
"-g", "1023", // AID_MEDIA_RW
"-m",
"-w",
"-G",
mRawPath.c_str(),
label.c_str(),
NULL)) {
PLOG(ERROR) << "Failed to exec";
}
LOG(ERROR) << "FUSE exiting";
_exit(1);
}
if (mFusePid == -1) {
PLOG(ERROR) << getId() << " failed to fork";
return -errno;
}
while (before == GetDevice(mFuseWrite)) {
LOG(VERBOSE) << "Waiting for FUSE to spin up...";
usleep(50000); // 50ms
}
/* sdcardfs will have exited already. FUSE will still be running */
TEMP_FAILURE_RETRY(waitpid(mFusePid, nullptr, WNOHANG));
return OK;
}
status_t EmulatedVolume::doUnmount() {
// Unmount the storage before we kill the FUSE process. If we kill
// the FUSE process first, most file system operations will return
// ENOTCONN until the unmount completes. This is an exotic and unusual
// error code and might cause broken behaviour in applications.
KillProcessesUsingPath(getPath());
ForceUnmount(mFuseDefault);
ForceUnmount(mFuseRead);
ForceUnmount(mFuseWrite);
if (mFusePid > 0) {
kill(mFusePid, SIGTERM);
TEMP_FAILURE_RETRY(waitpid(mFusePid, nullptr, 0));
mFusePid = 0;
}
rmdir(mFuseDefault.c_str());
rmdir(mFuseRead.c_str());
rmdir(mFuseWrite.c_str());
mFuseDefault.clear();
mFuseRead.clear();
mFuseWrite.clear();
return OK;
}
} // namespace vold
} // namespace android
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