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 <ctype.h>
20#include <fcntl.h>
21#include <stdint.h>
22#include <stdlib.h>
23#include <string.h>
24#include <sys/mount.h>
25#include <sys/stat.h>
26#include <sys/types.h>
27#include <sys/wait.h>
28#include <unistd.h>
29
30#include <algorithm>
31#include <string>
32#include <vector>
33
34#include <android-base/logging.h>
35#include <android-base/properties.h>
36#include <android-base/stringprintf.h>
37#include <android-base/unique_fd.h>
38#include <cryptfs.h>
39#include <ext4_utils/wipe.h>
40#include <fs_mgr.h>
41
42#include "mounts.h"
43
44static struct fstab* fstab = nullptr;
45
46extern struct selabel_handle* sehandle;
47
48void load_volume_table() {
49  fstab = fs_mgr_read_fstab_default();
50  if (!fstab) {
51    LOG(ERROR) << "Failed to read default fstab";
52    return;
53  }
54
55  int ret = fs_mgr_add_entry(fstab, "/tmp", "ramdisk", "ramdisk");
56  if (ret == -1) {
57    LOG(ERROR) << "Failed to add /tmp entry to fstab";
58    fs_mgr_free_fstab(fstab);
59    fstab = nullptr;
60    return;
61  }
62
63  printf("recovery filesystem table\n");
64  printf("=========================\n");
65  for (int i = 0; i < fstab->num_entries; ++i) {
66    const Volume* v = &fstab->recs[i];
67    printf("  %d %s %s %s %lld\n", i, v->mount_point, v->fs_type, v->blk_device, v->length);
68  }
69  printf("\n");
70}
71
72Volume* volume_for_mount_point(const std::string& mount_point) {
73  return fs_mgr_get_entry_for_mount_point(fstab, mount_point);
74}
75
76// Finds the volume specified by the given path. fs_mgr_get_entry_for_mount_point() does exact match
77// only, so it attempts the prefixes recursively (e.g. "/cache/recovery/last_log",
78// "/cache/recovery", "/cache", "/" for a given path of "/cache/recovery/last_log") and returns the
79// first match or nullptr.
80static Volume* volume_for_path(const char* path) {
81  if (path == nullptr || path[0] == '\0') return nullptr;
82  std::string str(path);
83  while (true) {
84    Volume* result = fs_mgr_get_entry_for_mount_point(fstab, str);
85    if (result != nullptr || str == "/") {
86      return result;
87    }
88    size_t slash = str.find_last_of('/');
89    if (slash == std::string::npos) return nullptr;
90    if (slash == 0) {
91      str = "/";
92    } else {
93      str = str.substr(0, slash);
94    }
95  }
96  return nullptr;
97}
98
99// Mount the volume specified by path at the given mount_point.
100int ensure_path_mounted_at(const char* path, const char* mount_point) {
101  Volume* v = volume_for_path(path);
102  if (v == nullptr) {
103    LOG(ERROR) << "unknown volume for path [" << path << "]";
104    return -1;
105  }
106  if (strcmp(v->fs_type, "ramdisk") == 0) {
107    // The ramdisk is always mounted.
108    return 0;
109  }
110
111  if (!scan_mounted_volumes()) {
112    LOG(ERROR) << "Failed to scan mounted volumes";
113    return -1;
114  }
115
116  if (!mount_point) {
117    mount_point = v->mount_point;
118  }
119
120  const MountedVolume* mv = find_mounted_volume_by_mount_point(mount_point);
121  if (mv != nullptr) {
122    // Volume is already mounted.
123    return 0;
124  }
125
126  mkdir(mount_point, 0755);  // in case it doesn't already exist
127
128  if (strcmp(v->fs_type, "ext4") == 0 || strcmp(v->fs_type, "squashfs") == 0 ||
129      strcmp(v->fs_type, "vfat") == 0) {
130    int result = mount(v->blk_device, mount_point, v->fs_type, v->flags, v->fs_options);
131    if (result == -1 && fs_mgr_is_formattable(v)) {
132      PLOG(ERROR) << "Failed to mount " << mount_point << "; formatting";
133      bool crypt_footer = fs_mgr_is_encryptable(v) && !strcmp(v->key_loc, "footer");
134      if (fs_mgr_do_format(v, crypt_footer) == 0) {
135        result = mount(v->blk_device, mount_point, v->fs_type, v->flags, v->fs_options);
136      } else {
137        PLOG(ERROR) << "Failed to format " << mount_point;
138        return -1;
139      }
140    }
141
142    if (result == -1) {
143      PLOG(ERROR) << "Failed to mount " << mount_point;
144      return -1;
145    }
146    return 0;
147  }
148
149  LOG(ERROR) << "unknown fs_type \"" << v->fs_type << "\" for " << mount_point;
150  return -1;
151}
152
153int ensure_path_mounted(const char* path) {
154  // Mount at the default mount point.
155  return ensure_path_mounted_at(path, nullptr);
156}
157
158int ensure_path_unmounted(const char* path) {
159  const Volume* v = volume_for_path(path);
160  if (v == nullptr) {
161    LOG(ERROR) << "unknown volume for path [" << path << "]";
162    return -1;
163  }
164  if (strcmp(v->fs_type, "ramdisk") == 0) {
165    // The ramdisk is always mounted; you can't unmount it.
166    return -1;
167  }
168
169  if (!scan_mounted_volumes()) {
170    LOG(ERROR) << "Failed to scan mounted volumes";
171    return -1;
172  }
173
174  MountedVolume* mv = find_mounted_volume_by_mount_point(v->mount_point);
175  if (mv == nullptr) {
176    // Volume is already unmounted.
177    return 0;
178  }
179
180  return unmount_mounted_volume(mv);
181}
182
183static int exec_cmd(const std::vector<std::string>& args) {
184  CHECK_NE(static_cast<size_t>(0), args.size());
185
186  std::vector<char*> argv(args.size());
187  std::transform(args.cbegin(), args.cend(), argv.begin(),
188                 [](const std::string& arg) { return const_cast<char*>(arg.c_str()); });
189  argv.push_back(nullptr);
190
191  pid_t child;
192  if ((child = fork()) == 0) {
193    execv(argv[0], argv.data());
194    _exit(EXIT_FAILURE);
195  }
196
197  int status;
198  waitpid(child, &status, 0);
199  if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
200    LOG(ERROR) << args[0] << " failed with status " << WEXITSTATUS(status);
201  }
202  return WEXITSTATUS(status);
203}
204
205static int64_t get_file_size(int fd, uint64_t reserve_len) {
206  struct stat buf;
207  int ret = fstat(fd, &buf);
208  if (ret) return 0;
209
210  int64_t computed_size;
211  if (S_ISREG(buf.st_mode)) {
212    computed_size = buf.st_size - reserve_len;
213  } else if (S_ISBLK(buf.st_mode)) {
214    uint64_t block_device_size = get_block_device_size(fd);
215    if (block_device_size < reserve_len ||
216        block_device_size > std::numeric_limits<int64_t>::max()) {
217      computed_size = 0;
218    } else {
219      computed_size = block_device_size - reserve_len;
220    }
221  } else {
222    computed_size = 0;
223  }
224
225  return computed_size;
226}
227
228int format_volume(const char* volume, const char* directory) {
229  const Volume* v = volume_for_path(volume);
230  if (v == nullptr) {
231    LOG(ERROR) << "unknown volume \"" << volume << "\"";
232    return -1;
233  }
234  if (strcmp(v->fs_type, "ramdisk") == 0) {
235    LOG(ERROR) << "can't format_volume \"" << volume << "\"";
236    return -1;
237  }
238  if (strcmp(v->mount_point, volume) != 0) {
239    LOG(ERROR) << "can't give path \"" << volume << "\" to format_volume";
240    return -1;
241  }
242  if (ensure_path_unmounted(volume) != 0) {
243    LOG(ERROR) << "format_volume: Failed to unmount \"" << v->mount_point << "\"";
244    return -1;
245  }
246  if (strcmp(v->fs_type, "ext4") != 0 && strcmp(v->fs_type, "f2fs") != 0) {
247    LOG(ERROR) << "format_volume: fs_type \"" << v->fs_type << "\" unsupported";
248    return -1;
249  }
250
251  // If there's a key_loc that looks like a path, it should be a block device for storing encryption
252  // metadata. Wipe it too.
253  if (v->key_loc != nullptr && v->key_loc[0] == '/') {
254    LOG(INFO) << "Wiping " << v->key_loc;
255    int fd = open(v->key_loc, O_WRONLY | O_CREAT, 0644);
256    if (fd == -1) {
257      PLOG(ERROR) << "format_volume: Failed to open " << v->key_loc;
258      return -1;
259    }
260    wipe_block_device(fd, get_file_size(fd));
261    close(fd);
262  }
263
264  int64_t length = 0;
265  if (v->length > 0) {
266    length = v->length;
267  } else if (v->length < 0 ||
268             (v->key_loc != nullptr && strcmp(v->key_loc, "footer") == 0)) {
269    android::base::unique_fd fd(open(v->blk_device, O_RDONLY));
270    if (fd == -1) {
271      PLOG(ERROR) << "format_volume: failed to open " << v->blk_device;
272      return -1;
273    }
274    length =
275        get_file_size(fd.get(), v->length ? -v->length : CRYPT_FOOTER_OFFSET);
276    if (length <= 0) {
277      LOG(ERROR) << "get_file_size: invalid size " << length << " for "
278                 << v->blk_device;
279      return -1;
280    }
281  }
282
283  if (strcmp(v->fs_type, "ext4") == 0) {
284    static constexpr int kBlockSize = 4096;
285    std::vector<std::string> mke2fs_args = {
286      "/sbin/mke2fs_static", "-F", "-t", "ext4", "-b", std::to_string(kBlockSize),
287    };
288
289    int raid_stride = v->logical_blk_size / kBlockSize;
290    int raid_stripe_width = v->erase_blk_size / kBlockSize;
291    // stride should be the max of 8KB and logical block size
292    if (v->logical_blk_size != 0 && v->logical_blk_size < 8192) {
293      raid_stride = 8192 / kBlockSize;
294    }
295    if (v->erase_blk_size != 0 && v->logical_blk_size != 0) {
296      mke2fs_args.push_back("-E");
297      mke2fs_args.push_back(
298          android::base::StringPrintf("stride=%d,stripe-width=%d", raid_stride, raid_stripe_width));
299    }
300    mke2fs_args.push_back(v->blk_device);
301    if (length != 0) {
302      mke2fs_args.push_back(std::to_string(length / kBlockSize));
303    }
304
305    int result = exec_cmd(mke2fs_args);
306    if (result == 0 && directory != nullptr) {
307      std::vector<std::string> e2fsdroid_args = {
308        "/sbin/e2fsdroid_static",
309        "-e",
310        "-f",
311        directory,
312        "-a",
313        volume,
314        v->blk_device,
315      };
316      result = exec_cmd(e2fsdroid_args);
317    }
318
319    if (result != 0) {
320      PLOG(ERROR) << "format_volume: Failed to make ext4 on " << v->blk_device;
321      return -1;
322    }
323    return 0;
324  }
325
326  // Has to be f2fs because we checked earlier.
327  static constexpr int kSectorSize = 4096;
328  std::string cmd("/sbin/mkfs.f2fs");
329  // clang-format off
330  std::vector<std::string> make_f2fs_cmd = {
331    cmd,
332    "-d1",
333    "-f",
334    "-O", "encrypt",
335    "-O", "quota",
336    "-O", "verity",
337    "-w", std::to_string(kSectorSize),
338    v->blk_device,
339  };
340  // clang-format on
341  if (length >= kSectorSize) {
342    make_f2fs_cmd.push_back(std::to_string(length / kSectorSize));
343  }
344
345  int result = exec_cmd(make_f2fs_cmd);
346  if (result == 0 && directory != nullptr) {
347    cmd = "/sbin/sload.f2fs";
348    // clang-format off
349    std::vector<std::string> sload_f2fs_cmd = {
350      cmd,
351      "-f", directory,
352      "-t", volume,
353      v->blk_device,
354    };
355    // clang-format on
356    result = exec_cmd(sload_f2fs_cmd);
357  }
358  if (result != 0) {
359    PLOG(ERROR) << "format_volume: Failed " << cmd << " on " << v->blk_device;
360    return -1;
361  }
362  return 0;
363}
364
365int format_volume(const char* volume) {
366  return format_volume(volume, nullptr);
367}
368
369int setup_install_mounts() {
370  if (fstab == nullptr) {
371    LOG(ERROR) << "can't set up install mounts: no fstab loaded";
372    return -1;
373  }
374  for (int i = 0; i < fstab->num_entries; ++i) {
375    const Volume* v = fstab->recs + i;
376
377    // We don't want to do anything with "/".
378    if (strcmp(v->mount_point, "/") == 0) {
379      continue;
380    }
381
382    if (strcmp(v->mount_point, "/tmp") == 0 || strcmp(v->mount_point, "/cache") == 0) {
383      if (ensure_path_mounted(v->mount_point) != 0) {
384        LOG(ERROR) << "Failed to mount " << v->mount_point;
385        return -1;
386      }
387    } else {
388      if (ensure_path_unmounted(v->mount_point) != 0) {
389        LOG(ERROR) << "Failed to unmount " << v->mount_point;
390        return -1;
391      }
392    }
393  }
394  return 0;
395}
396