1 /*
2 * Copyright (C) 2008 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 #define ATRACE_TAG ATRACE_TAG_PACKAGE_MANAGER
18
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <dirent.h>
22 #include <fcntl.h>
23 #include <unistd.h>
24 #include <errno.h>
25 #include <string.h>
26
27 #include <sys/mount.h>
28 #include <sys/types.h>
29 #include <sys/stat.h>
30 #include <sys/ioctl.h>
31
32 #include <linux/kdev_t.h>
33
34 #include <android-base/logging.h>
35 #include <android-base/strings.h>
36 #include <android-base/stringprintf.h>
37 #include <android-base/unique_fd.h>
38 #include <utils/Trace.h>
39
40 #include "Loop.h"
41 #include "VoldUtil.h"
42 #include "sehandle.h"
43
44 using android::base::StringPrintf;
45 using android::base::unique_fd;
46
47 static const char* kVoldPrefix = "vold:";
48
create(const std::string & target,std::string & out_device)49 int Loop::create(const std::string& target, std::string& out_device) {
50 unique_fd ctl_fd(open("/dev/loop-control", O_RDWR | O_CLOEXEC));
51 if (ctl_fd.get() == -1) {
52 PLOG(ERROR) << "Failed to open loop-control";
53 return -errno;
54 }
55
56 int num = ioctl(ctl_fd.get(), LOOP_CTL_GET_FREE);
57 if (num == -1) {
58 PLOG(ERROR) << "Failed LOOP_CTL_GET_FREE";
59 return -errno;
60 }
61
62 out_device = StringPrintf("/dev/block/loop%d", num);
63
64 unique_fd target_fd(open(target.c_str(), O_RDWR | O_CLOEXEC));
65 if (target_fd.get() == -1) {
66 PLOG(ERROR) << "Failed to open " << target;
67 return -errno;
68 }
69 unique_fd device_fd(open(out_device.c_str(), O_RDWR | O_CLOEXEC));
70 if (device_fd.get() == -1) {
71 PLOG(ERROR) << "Failed to open " << out_device;
72 return -errno;
73 }
74
75 if (ioctl(device_fd.get(), LOOP_SET_FD, target_fd.get()) == -1) {
76 PLOG(ERROR) << "Failed to LOOP_SET_FD";
77 return -errno;
78 }
79
80 struct loop_info64 li;
81 memset(&li, 0, sizeof(li));
82 strlcpy((char*) li.lo_crypt_name, kVoldPrefix, LO_NAME_SIZE);
83 if (ioctl(device_fd.get(), LOOP_SET_STATUS64, &li) == -1) {
84 PLOG(ERROR) << "Failed to LOOP_SET_STATUS64";
85 return -errno;
86 }
87
88 return 0;
89 }
90
destroyByDevice(const char * loopDevice)91 int Loop::destroyByDevice(const char *loopDevice) {
92 int device_fd;
93
94 device_fd = open(loopDevice, O_RDONLY | O_CLOEXEC);
95 if (device_fd < 0) {
96 PLOG(ERROR) << "Failed to open " << loopDevice;
97 return -1;
98 }
99
100 if (ioctl(device_fd, LOOP_CLR_FD, 0) < 0) {
101 PLOG(ERROR) << "Failed to destroy " << loopDevice;
102 close(device_fd);
103 return -1;
104 }
105
106 close(device_fd);
107 return 0;
108 }
109
destroyAll()110 int Loop::destroyAll() {
111 ATRACE_NAME("Loop::destroyAll");
112
113 std::string root = "/dev/block/";
114 auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(root.c_str()), closedir);
115 if (!dirp) {
116 PLOG(ERROR) << "Failed to opendir";
117 return -1;
118 }
119
120 // Poke through all devices looking for loops
121 struct dirent* de;
122 while ((de = readdir(dirp.get()))) {
123 auto test = std::string(de->d_name);
124 if (!android::base::StartsWith(test, "loop")) continue;
125
126 auto path = root + de->d_name;
127 unique_fd fd(open(path.c_str(), O_RDWR | O_CLOEXEC));
128 if (fd.get() == -1) {
129 if (errno != ENOENT) {
130 PLOG(WARNING) << "Failed to open " << path;
131 }
132 continue;
133 }
134
135 struct loop_info64 li;
136 if (ioctl(fd.get(), LOOP_GET_STATUS64, &li) < 0) {
137 PLOG(WARNING) << "Failed to LOOP_GET_STATUS64 " << path;
138 continue;
139 }
140
141 auto id = std::string((char*) li.lo_crypt_name);
142 if (android::base::StartsWith(id, kVoldPrefix)) {
143 LOG(DEBUG) << "Tearing down stale loop device at " << path << " named " << id;
144
145 if (ioctl(fd.get(), LOOP_CLR_FD, 0) < 0) {
146 PLOG(WARNING) << "Failed to LOOP_CLR_FD " << path;
147 }
148 } else {
149 LOG(VERBOSE) << "Found unmanaged loop device at " << path << " named " << id;
150 }
151 }
152
153 return 0;
154 }
155
createImageFile(const char * file,unsigned long numSectors)156 int Loop::createImageFile(const char *file, unsigned long numSectors) {
157 unique_fd fd(open(file, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, 0600));
158 if (fd.get() == -1) {
159 PLOG(ERROR) << "Failed to create image " << file;
160 return -errno;
161 }
162 if (fallocate(fd.get(), 0, 0, numSectors * 512) == -1) {
163 PLOG(WARNING) << "Failed to fallocate; falling back to ftruncate";
164 if (ftruncate(fd, numSectors * 512) == -1) {
165 PLOG(ERROR) << "Failed to ftruncate";
166 return -errno;
167 }
168 }
169 return 0;
170 }
171
resizeImageFile(const char * file,unsigned long numSectors)172 int Loop::resizeImageFile(const char *file, unsigned long numSectors) {
173 int fd;
174
175 if ((fd = open(file, O_RDWR | O_CLOEXEC)) < 0) {
176 PLOG(ERROR) << "Failed to open " << file;
177 return -1;
178 }
179
180 LOG(DEBUG) << "Attempting to increase " << file << " to " << numSectors;
181
182 if (fallocate(fd, 0, 0, numSectors * 512)) {
183 if (errno == ENOSYS || errno == ENOTSUP) {
184 PLOG(WARNING) << "fallocate not found. Falling back to ftruncate.";
185 if (ftruncate(fd, numSectors * 512) < 0) {
186 PLOG(ERROR) << "Failed to ftruncate";
187 close(fd);
188 return -1;
189 }
190 } else {
191 PLOG(ERROR) << "Failed to fallocate";
192 close(fd);
193 return -1;
194 }
195 }
196 close(fd);
197 return 0;
198 }
199