1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "EmulatedVolume.h"
18#include "Utils.h"
19
20#include <android-base/stringprintf.h>
21#include <android-base/logging.h>
22#include <cutils/fs.h>
23#include <private/android_filesystem_config.h>
24
25#include <fcntl.h>
26#include <stdlib.h>
27#include <sys/mount.h>
28#include <sys/stat.h>
29#include <sys/types.h>
30#include <sys/wait.h>
31
32using android::base::StringPrintf;
33
34namespace android {
35namespace vold {
36
37static const char* kFusePath = "/system/bin/sdcard";
38
39EmulatedVolume::EmulatedVolume(const std::string& rawPath) :
40        VolumeBase(Type::kEmulated), mFusePid(0) {
41    setId("emulated");
42    mRawPath = rawPath;
43    mLabel = "emulated";
44}
45
46EmulatedVolume::EmulatedVolume(const std::string& rawPath, dev_t device,
47        const std::string& fsUuid) : VolumeBase(Type::kEmulated), mFusePid(0) {
48    setId(StringPrintf("emulated:%u,%u", major(device), minor(device)));
49    mRawPath = rawPath;
50    mLabel = fsUuid;
51}
52
53EmulatedVolume::~EmulatedVolume() {
54}
55
56status_t EmulatedVolume::doMount() {
57    // We could have migrated storage to an adopted private volume, so always
58    // call primary storage "emulated" to avoid media rescans.
59    std::string label = mLabel;
60    if (getMountFlags() & MountFlags::kPrimary) {
61        label = "emulated";
62    }
63
64    mFuseDefault = StringPrintf("/mnt/runtime/default/%s", label.c_str());
65    mFuseRead = StringPrintf("/mnt/runtime/read/%s", label.c_str());
66    mFuseWrite = StringPrintf("/mnt/runtime/write/%s", label.c_str());
67
68    setInternalPath(mRawPath);
69    setPath(StringPrintf("/storage/%s", label.c_str()));
70
71    if (fs_prepare_dir(mFuseDefault.c_str(), 0700, AID_ROOT, AID_ROOT) ||
72            fs_prepare_dir(mFuseRead.c_str(), 0700, AID_ROOT, AID_ROOT) ||
73            fs_prepare_dir(mFuseWrite.c_str(), 0700, AID_ROOT, AID_ROOT)) {
74        PLOG(ERROR) << getId() << " failed to create mount points";
75        return -errno;
76    }
77
78    dev_t before = GetDevice(mFuseWrite);
79
80    if (!(mFusePid = fork())) {
81        if (execl(kFusePath, kFusePath,
82                "-u", "1023", // AID_MEDIA_RW
83                "-g", "1023", // AID_MEDIA_RW
84                "-m",
85                "-w",
86                mRawPath.c_str(),
87                label.c_str(),
88                NULL)) {
89            PLOG(ERROR) << "Failed to exec";
90        }
91
92        LOG(ERROR) << "FUSE exiting";
93        _exit(1);
94    }
95
96    if (mFusePid == -1) {
97        PLOG(ERROR) << getId() << " failed to fork";
98        return -errno;
99    }
100
101    while (before == GetDevice(mFuseWrite)) {
102        LOG(VERBOSE) << "Waiting for FUSE to spin up...";
103        usleep(50000); // 50ms
104    }
105
106    return OK;
107}
108
109status_t EmulatedVolume::doUnmount() {
110    // Unmount the storage before we kill the FUSE process. If we kill
111    // the FUSE process first, most file system operations will return
112    // ENOTCONN until the unmount completes. This is an exotic and unusual
113    // error code and might cause broken behaviour in applications.
114    KillProcessesUsingPath(getPath());
115    ForceUnmount(mFuseDefault);
116    ForceUnmount(mFuseRead);
117    ForceUnmount(mFuseWrite);
118
119    if (mFusePid > 0) {
120        kill(mFusePid, SIGTERM);
121        TEMP_FAILURE_RETRY(waitpid(mFusePid, nullptr, 0));
122        mFusePid = 0;
123    }
124
125    rmdir(mFuseDefault.c_str());
126    rmdir(mFuseRead.c_str());
127    rmdir(mFuseWrite.c_str());
128
129    mFuseDefault.clear();
130    mFuseRead.clear();
131    mFuseWrite.clear();
132
133    return OK;
134}
135
136}  // namespace vold
137}  // namespace android
138