1 /*
2 * Copyright (C) 2007 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 "roots.h"
18
19 #include <errno.h>
20 #include <stdlib.h>
21 #include <sys/mount.h>
22 #include <sys/stat.h>
23 #include <sys/types.h>
24 #include <sys/wait.h>
25 #include <unistd.h>
26 #include <ctype.h>
27 #include <fcntl.h>
28
29 #include <android-base/logging.h>
30 #include <android-base/properties.h>
31 #include <android-base/stringprintf.h>
32 #include <android-base/unique_fd.h>
33 #include <ext4_utils/wipe.h>
34 #include <fs_mgr.h>
35
36 #include "common.h"
37 #include "mounts.h"
38 #include "cryptfs.h"
39
40 static struct fstab *fstab = NULL;
41
42 extern struct selabel_handle *sehandle;
43
load_volume_table()44 void load_volume_table()
45 {
46 int i;
47 int ret;
48
49 fstab = fs_mgr_read_fstab_default();
50 if (!fstab) {
51 LOG(ERROR) << "failed to read default fstab";
52 return;
53 }
54
55 ret = fs_mgr_add_entry(fstab, "/tmp", "ramdisk", "ramdisk");
56 if (ret < 0 ) {
57 LOG(ERROR) << "failed to add /tmp entry to fstab";
58 fs_mgr_free_fstab(fstab);
59 fstab = NULL;
60 return;
61 }
62
63 printf("recovery filesystem table\n");
64 printf("=========================\n");
65 for (i = 0; i < fstab->num_entries; ++i) {
66 Volume* v = &fstab->recs[i];
67 printf(" %d %s %s %s %lld\n", i, v->mount_point, v->fs_type,
68 v->blk_device, v->length);
69 }
70 printf("\n");
71 }
72
volume_for_path(const char * path)73 Volume* volume_for_path(const char* path) {
74 return fs_mgr_get_entry_for_mount_point(fstab, path);
75 }
76
77 // Mount the volume specified by path at the given mount_point.
ensure_path_mounted_at(const char * path,const char * mount_point)78 int ensure_path_mounted_at(const char* path, const char* mount_point) {
79 Volume* v = volume_for_path(path);
80 if (v == NULL) {
81 LOG(ERROR) << "unknown volume for path [" << path << "]";
82 return -1;
83 }
84 if (strcmp(v->fs_type, "ramdisk") == 0) {
85 // the ramdisk is always mounted.
86 return 0;
87 }
88
89 if (!scan_mounted_volumes()) {
90 LOG(ERROR) << "failed to scan mounted volumes";
91 return -1;
92 }
93
94 if (!mount_point) {
95 mount_point = v->mount_point;
96 }
97
98 MountedVolume* mv = find_mounted_volume_by_mount_point(mount_point);
99 if (mv) {
100 // volume is already mounted
101 return 0;
102 }
103
104 mkdir(mount_point, 0755); // in case it doesn't already exist
105
106 if (strcmp(v->fs_type, "ext4") == 0 ||
107 strcmp(v->fs_type, "squashfs") == 0 ||
108 strcmp(v->fs_type, "vfat") == 0) {
109 int result = mount(v->blk_device, mount_point, v->fs_type, v->flags, v->fs_options);
110 if (result == -1 && fs_mgr_is_formattable(v)) {
111 LOG(ERROR) << "failed to mount " << mount_point << " (" << strerror(errno)
112 << ") , formatting.....";
113 bool crypt_footer = fs_mgr_is_encryptable(v) && !strcmp(v->key_loc, "footer");
114 if (fs_mgr_do_format(v, crypt_footer) == 0) {
115 result = mount(v->blk_device, mount_point, v->fs_type, v->flags, v->fs_options);
116 } else {
117 PLOG(ERROR) << "failed to format " << mount_point;
118 return -1;
119 }
120 }
121
122 if (result == -1) {
123 PLOG(ERROR) << "failed to mount " << mount_point;
124 return -1;
125 }
126 return 0;
127 }
128
129 LOG(ERROR) << "unknown fs_type \"" << v->fs_type << "\" for " << mount_point;
130 return -1;
131 }
132
ensure_path_mounted(const char * path)133 int ensure_path_mounted(const char* path) {
134 // Mount at the default mount point.
135 return ensure_path_mounted_at(path, nullptr);
136 }
137
ensure_path_unmounted(const char * path)138 int ensure_path_unmounted(const char* path) {
139 Volume* v = volume_for_path(path);
140 if (v == NULL) {
141 LOG(ERROR) << "unknown volume for path [" << path << "]";
142 return -1;
143 }
144 if (strcmp(v->fs_type, "ramdisk") == 0) {
145 // the ramdisk is always mounted; you can't unmount it.
146 return -1;
147 }
148
149 if (!scan_mounted_volumes()) {
150 LOG(ERROR) << "failed to scan mounted volumes";
151 return -1;
152 }
153
154 MountedVolume* mv = find_mounted_volume_by_mount_point(v->mount_point);
155 if (mv == NULL) {
156 // volume is already unmounted
157 return 0;
158 }
159
160 return unmount_mounted_volume(mv);
161 }
162
exec_cmd(const char * path,char * const argv[])163 static int exec_cmd(const char* path, char* const argv[]) {
164 int status;
165 pid_t child;
166 if ((child = vfork()) == 0) {
167 execv(path, argv);
168 _exit(EXIT_FAILURE);
169 }
170 waitpid(child, &status, 0);
171 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
172 LOG(ERROR) << path << " failed with status " << WEXITSTATUS(status);
173 }
174 return WEXITSTATUS(status);
175 }
176
get_file_size(int fd,uint64_t reserve_len)177 static ssize_t get_file_size(int fd, uint64_t reserve_len) {
178 struct stat buf;
179 int ret = fstat(fd, &buf);
180 if (ret) return 0;
181
182 ssize_t computed_size;
183 if (S_ISREG(buf.st_mode)) {
184 computed_size = buf.st_size - reserve_len;
185 } else if (S_ISBLK(buf.st_mode)) {
186 computed_size = get_block_device_size(fd) - reserve_len;
187 } else {
188 computed_size = 0;
189 }
190
191 return computed_size;
192 }
193
format_volume(const char * volume,const char * directory)194 int format_volume(const char* volume, const char* directory) {
195 Volume* v = volume_for_path(volume);
196 if (v == NULL) {
197 LOG(ERROR) << "unknown volume \"" << volume << "\"";
198 return -1;
199 }
200 if (strcmp(v->fs_type, "ramdisk") == 0) {
201 // you can't format the ramdisk.
202 LOG(ERROR) << "can't format_volume \"" << volume << "\"";
203 return -1;
204 }
205 if (strcmp(v->mount_point, volume) != 0) {
206 LOG(ERROR) << "can't give path \"" << volume << "\" to format_volume";
207 return -1;
208 }
209
210 if (ensure_path_unmounted(volume) != 0) {
211 LOG(ERROR) << "format_volume failed to unmount \"" << v->mount_point << "\"";
212 return -1;
213 }
214
215 if (strcmp(v->fs_type, "ext4") == 0 || strcmp(v->fs_type, "f2fs") == 0) {
216 // if there's a key_loc that looks like a path, it should be a
217 // block device for storing encryption metadata. wipe it too.
218 if (v->key_loc != NULL && v->key_loc[0] == '/') {
219 LOG(INFO) << "wiping " << v->key_loc;
220 int fd = open(v->key_loc, O_WRONLY | O_CREAT, 0644);
221 if (fd < 0) {
222 LOG(ERROR) << "format_volume: failed to open " << v->key_loc;
223 return -1;
224 }
225 wipe_block_device(fd, get_file_size(fd));
226 close(fd);
227 }
228
229 ssize_t length = 0;
230 if (v->length != 0) {
231 length = v->length;
232 } else if (v->key_loc != NULL && strcmp(v->key_loc, "footer") == 0) {
233 android::base::unique_fd fd(open(v->blk_device, O_RDONLY));
234 if (fd < 0) {
235 PLOG(ERROR) << "get_file_size: failed to open " << v->blk_device;
236 return -1;
237 }
238 length = get_file_size(fd.get(), CRYPT_FOOTER_OFFSET);
239 if (length <= 0) {
240 LOG(ERROR) << "get_file_size: invalid size " << length << " for " << v->blk_device;
241 return -1;
242 }
243 }
244 int result;
245 if (strcmp(v->fs_type, "ext4") == 0) {
246 static constexpr int block_size = 4096;
247 int raid_stride = v->logical_blk_size / block_size;
248 int raid_stripe_width = v->erase_blk_size / block_size;
249
250 // stride should be the max of 8kb and logical block size
251 if (v->logical_blk_size != 0 && v->logical_blk_size < 8192) {
252 raid_stride = 8192 / block_size;
253 }
254
255 const char* mke2fs_argv[] = { "/sbin/mke2fs_static",
256 "-F",
257 "-t",
258 "ext4",
259 "-b",
260 nullptr,
261 nullptr,
262 nullptr,
263 nullptr,
264 nullptr,
265 nullptr };
266
267 int i = 5;
268 std::string block_size_str = std::to_string(block_size);
269 mke2fs_argv[i++] = block_size_str.c_str();
270
271 std::string ext_args;
272 if (v->erase_blk_size != 0 && v->logical_blk_size != 0) {
273 ext_args = android::base::StringPrintf("stride=%d,stripe-width=%d", raid_stride,
274 raid_stripe_width);
275 mke2fs_argv[i++] = "-E";
276 mke2fs_argv[i++] = ext_args.c_str();
277 }
278
279 mke2fs_argv[i++] = v->blk_device;
280
281 std::string size_str = std::to_string(length / block_size);
282 if (length != 0) {
283 mke2fs_argv[i++] = size_str.c_str();
284 }
285
286 result = exec_cmd(mke2fs_argv[0], const_cast<char**>(mke2fs_argv));
287 if (result == 0 && directory != nullptr) {
288 const char* e2fsdroid_argv[] = { "/sbin/e2fsdroid_static",
289 "-e",
290 "-f",
291 directory,
292 "-a",
293 volume,
294 v->blk_device,
295 nullptr };
296
297 result = exec_cmd(e2fsdroid_argv[0], const_cast<char**>(e2fsdroid_argv));
298 }
299 } else { /* Has to be f2fs because we checked earlier. */
300 char *num_sectors = nullptr;
301 if (length >= 512 && asprintf(&num_sectors, "%zd", length / 512) <= 0) {
302 LOG(ERROR) << "format_volume: failed to create " << v->fs_type
303 << " command for " << v->blk_device;
304 return -1;
305 }
306 const char *f2fs_path = "/sbin/mkfs.f2fs";
307 const char* const f2fs_argv[] = {"mkfs.f2fs", "-t", "-d1", v->blk_device, num_sectors, nullptr};
308
309 result = exec_cmd(f2fs_path, (char* const*)f2fs_argv);
310 free(num_sectors);
311 }
312 if (result != 0) {
313 PLOG(ERROR) << "format_volume: make " << v->fs_type << " failed on " << v->blk_device;
314 return -1;
315 }
316 return 0;
317 }
318
319 LOG(ERROR) << "format_volume: fs_type \"" << v->fs_type << "\" unsupported";
320 return -1;
321 }
322
format_volume(const char * volume)323 int format_volume(const char* volume) {
324 return format_volume(volume, NULL);
325 }
326
setup_install_mounts()327 int setup_install_mounts() {
328 if (fstab == nullptr) {
329 LOG(ERROR) << "can't set up install mounts: no fstab loaded";
330 return -1;
331 }
332 for (int i = 0; i < fstab->num_entries; ++i) {
333 const Volume* v = fstab->recs + i;
334
335 // We don't want to do anything with "/".
336 if (strcmp(v->mount_point, "/") == 0) {
337 continue;
338 }
339
340 if (strcmp(v->mount_point, "/tmp") == 0 || strcmp(v->mount_point, "/cache") == 0) {
341 if (ensure_path_mounted(v->mount_point) != 0) {
342 LOG(ERROR) << "failed to mount " << v->mount_point;
343 return -1;
344 }
345 } else {
346 if (ensure_path_unmounted(v->mount_point) != 0) {
347 LOG(ERROR) << "failed to unmount " << v->mount_point;
348 return -1;
349 }
350 }
351 }
352 return 0;
353 }
354