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 <base/stringprintf.h>
21 #include <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
32 using android::base::StringPrintf;
33
34 namespace android {
35 namespace vold {
36
37 static const char* kFusePath = "/system/bin/sdcard";
38
EmulatedVolume(const std::string & rawPath)39 EmulatedVolume::EmulatedVolume(const std::string& rawPath) :
40 VolumeBase(Type::kEmulated), mFusePid(0) {
41 setId("emulated");
42 mRawPath = rawPath;
43 mLabel = "emulated";
44 }
45
EmulatedVolume(const std::string & rawPath,dev_t device,const std::string & fsUuid)46 EmulatedVolume::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
~EmulatedVolume()53 EmulatedVolume::~EmulatedVolume() {
54 }
55
doMount()56 status_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
doUnmount()109 status_t EmulatedVolume::doUnmount() {
110 if (mFusePid > 0) {
111 kill(mFusePid, SIGTERM);
112 TEMP_FAILURE_RETRY(waitpid(mFusePid, nullptr, 0));
113 mFusePid = 0;
114 }
115
116 ForceUnmount(mFuseDefault);
117 ForceUnmount(mFuseRead);
118 ForceUnmount(mFuseWrite);
119
120 rmdir(mFuseDefault.c_str());
121 rmdir(mFuseRead.c_str());
122 rmdir(mFuseWrite.c_str());
123
124 mFuseDefault.clear();
125 mFuseRead.clear();
126 mFuseWrite.clear();
127
128 return OK;
129 }
130
131 } // namespace vold
132 } // namespace android
133