PublicVolume.cpp revision 11c2d380a786d9e304416be98881b90b74ff666d 
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 "fs/Vfat.h"
18#include "PublicVolume.h"
19#include "Utils.h"
20#include "VolumeManager.h"
21#include "ResponseCode.h"
22
23#include <android-base/stringprintf.h>
24#include <android-base/logging.h>
25#include <cutils/fs.h>
26#include <private/android_filesystem_config.h>
27
28#include <fcntl.h>
29#include <stdlib.h>
30#include <sys/mount.h>
31#include <sys/stat.h>
32#include <sys/types.h>
33#include <sys/sysmacros.h>
34#include <sys/wait.h>
35
36using android::base::StringPrintf;
37
38namespace android {
39namespace vold {
40
41static const char* kFusePath = "/system/bin/sdcard";
42
43static const char* kAsecPath = "/mnt/secure/asec";
44
45PublicVolume::PublicVolume(dev_t device) :
46        VolumeBase(Type::kPublic), mDevice(device), mFusePid(0) {
47    setId(StringPrintf("public:%u,%u", major(device), minor(device)));
48    mDevPath = StringPrintf("/dev/block/vold/%s", getId().c_str());
49}
50
51PublicVolume::~PublicVolume() {
52}
53
54status_t PublicVolume::readMetadata() {
55    status_t res = ReadMetadataUntrusted(mDevPath, mFsType, mFsUuid, mFsLabel);
56    notifyEvent(ResponseCode::VolumeFsTypeChanged, mFsType);
57    notifyEvent(ResponseCode::VolumeFsUuidChanged, mFsUuid);
58    notifyEvent(ResponseCode::VolumeFsLabelChanged, mFsLabel);
59    return res;
60}
61
62status_t PublicVolume::initAsecStage() {
63    std::string legacyPath(mRawPath + "/android_secure");
64    std::string securePath(mRawPath + "/.android_secure");
65
66    // Recover legacy secure path
67    if (!access(legacyPath.c_str(), R_OK | X_OK)
68            && access(securePath.c_str(), R_OK | X_OK)) {
69        if (rename(legacyPath.c_str(), securePath.c_str())) {
70            PLOG(WARNING) << getId() << " failed to rename legacy ASEC dir";
71        }
72    }
73
74    if (TEMP_FAILURE_RETRY(mkdir(securePath.c_str(), 0700))) {
75        if (errno != EEXIST) {
76            PLOG(WARNING) << getId() << " creating ASEC stage failed";
77            return -errno;
78        }
79    }
80
81    BindMount(securePath, kAsecPath);
82
83    return OK;
84}
85
86status_t PublicVolume::doCreate() {
87    return CreateDeviceNode(mDevPath, mDevice);
88}
89
90status_t PublicVolume::doDestroy() {
91    return DestroyDeviceNode(mDevPath);
92}
93
94status_t PublicVolume::doMount() {
95    // TODO: expand to support mounting other filesystems
96    readMetadata();
97
98    if (mFsType != "vfat") {
99        LOG(ERROR) << getId() << " unsupported filesystem " << mFsType;
100        return -EIO;
101    }
102
103    if (vfat::Check(mDevPath)) {
104        LOG(ERROR) << getId() << " failed filesystem check";
105        return -EIO;
106    }
107
108    // Use UUID as stable name, if available
109    std::string stableName = getId();
110    if (!mFsUuid.empty()) {
111        stableName = mFsUuid;
112    }
113
114    mRawPath = StringPrintf("/mnt/media_rw/%s", stableName.c_str());
115
116    mFuseDefault = StringPrintf("/mnt/runtime/default/%s", stableName.c_str());
117    mFuseRead = StringPrintf("/mnt/runtime/read/%s", stableName.c_str());
118    mFuseWrite = StringPrintf("/mnt/runtime/write/%s", stableName.c_str());
119
120    setInternalPath(mRawPath);
121    if (getMountFlags() & MountFlags::kVisible) {
122        setPath(StringPrintf("/storage/%s", stableName.c_str()));
123    } else {
124        setPath(mRawPath);
125    }
126
127    if (fs_prepare_dir(mRawPath.c_str(), 0700, AID_ROOT, AID_ROOT)) {
128        PLOG(ERROR) << getId() << " failed to create mount points";
129        return -errno;
130    }
131
132    if (vfat::Mount(mDevPath, mRawPath, false, false, false,
133            AID_MEDIA_RW, AID_MEDIA_RW, 0007, true)) {
134        PLOG(ERROR) << getId() << " failed to mount " << mDevPath;
135        return -EIO;
136    }
137
138    if (getMountFlags() & MountFlags::kPrimary) {
139        initAsecStage();
140    }
141
142    if (!(getMountFlags() & MountFlags::kVisible)) {
143        // Not visible to apps, so no need to spin up FUSE
144        return OK;
145    }
146
147    if (fs_prepare_dir(mFuseDefault.c_str(), 0700, AID_ROOT, AID_ROOT) ||
148            fs_prepare_dir(mFuseRead.c_str(), 0700, AID_ROOT, AID_ROOT) ||
149            fs_prepare_dir(mFuseWrite.c_str(), 0700, AID_ROOT, AID_ROOT)) {
150        PLOG(ERROR) << getId() << " failed to create FUSE mount points";
151        return -errno;
152    }
153
154    dev_t before = GetDevice(mFuseWrite);
155
156    if (!(mFusePid = fork())) {
157        if (getMountFlags() & MountFlags::kPrimary) {
158            if (execl(kFusePath, kFusePath,
159                    "-u", "1023", // AID_MEDIA_RW
160                    "-g", "1023", // AID_MEDIA_RW
161                    "-U", std::to_string(getMountUserId()).c_str(),
162                    "-w",
163                    mRawPath.c_str(),
164                    stableName.c_str(),
165                    NULL)) {
166                PLOG(ERROR) << "Failed to exec";
167            }
168        } else {
169            if (execl(kFusePath, kFusePath,
170                    "-u", "1023", // AID_MEDIA_RW
171                    "-g", "1023", // AID_MEDIA_RW
172                    "-U", std::to_string(getMountUserId()).c_str(),
173                    mRawPath.c_str(),
174                    stableName.c_str(),
175                    NULL)) {
176                PLOG(ERROR) << "Failed to exec";
177            }
178        }
179
180        LOG(ERROR) << "FUSE exiting";
181        _exit(1);
182    }
183
184    if (mFusePid == -1) {
185        PLOG(ERROR) << getId() << " failed to fork";
186        return -errno;
187    }
188
189    while (before == GetDevice(mFuseWrite)) {
190        LOG(VERBOSE) << "Waiting for FUSE to spin up...";
191        usleep(50000); // 50ms
192    }
193    /* sdcardfs will have exited already. FUSE will still be running */
194    TEMP_FAILURE_RETRY(waitpid(mFusePid, nullptr, WNOHANG));
195
196    return OK;
197}
198
199status_t PublicVolume::doUnmount() {
200    // Unmount the storage before we kill the FUSE process. If we kill
201    // the FUSE process first, most file system operations will return
202    // ENOTCONN until the unmount completes. This is an exotic and unusual
203    // error code and might cause broken behaviour in applications.
204    KillProcessesUsingPath(getPath());
205
206    ForceUnmount(kAsecPath);
207
208    ForceUnmount(mFuseDefault);
209    ForceUnmount(mFuseRead);
210    ForceUnmount(mFuseWrite);
211    ForceUnmount(mRawPath);
212
213    if (mFusePid > 0) {
214        kill(mFusePid, SIGTERM);
215        TEMP_FAILURE_RETRY(waitpid(mFusePid, nullptr, 0));
216        mFusePid = 0;
217    }
218
219    rmdir(mFuseDefault.c_str());
220    rmdir(mFuseRead.c_str());
221    rmdir(mFuseWrite.c_str());
222    rmdir(mRawPath.c_str());
223
224    mFuseDefault.clear();
225    mFuseRead.clear();
226    mFuseWrite.clear();
227    mRawPath.clear();
228
229    return OK;
230}
231
232status_t PublicVolume::doFormat(const std::string& fsType) {
233    if (fsType == "vfat" || fsType == "auto") {
234        if (WipeBlockDevice(mDevPath) != OK) {
235            LOG(WARNING) << getId() << " failed to wipe";
236        }
237        if (vfat::Format(mDevPath, 0)) {
238            LOG(ERROR) << getId() << " failed to format";
239            return -errno;
240        }
241    } else {
242        LOG(ERROR) << "Unsupported filesystem " << fsType;
243        return -EINVAL;
244    }
245
246    return OK;
247}
248
249}  // namespace vold
250}  // namespace android
251