roots.cpp - android_bootable_recovery - Gitiles

 /*
  * Copyright (C) 2007 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "roots.h"

 #include <ctype.h>
 #include <fcntl.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>

 #include <algorithm>
 #include <string>
 #include <vector>

 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/unique_fd.h>
 #include <cryptfs.h>
 #include <ext4_utils/wipe.h>
 #include <fs_mgr.h>

 #include "mounts.h"

 static struct fstab* fstab = nullptr;

 extern struct selabel_handle* sehandle;

 void load_volume_table() {
   fstab = fs_mgr_read_fstab_default();
   if (!fstab) {
     LOG(ERROR) << "Failed to read default fstab";
     return;
   }

   int ret = fs_mgr_add_entry(fstab, "/tmp", "ramdisk", "ramdisk");
   if (ret == -1) {
     LOG(ERROR) << "Failed to add /tmp entry to fstab";
     fs_mgr_free_fstab(fstab);
     fstab = nullptr;
     return;
   }

   printf("recovery filesystem table\n");
   printf("=========================\n");
   for (int i = 0; i < fstab->num_entries; ++i) {
     const Volume* v = &fstab->recs[i];
     printf("  %d %s %s %s %lld\n", i, v->mount_point, v->fs_type, v->blk_device, v->length);
   }
   printf("\n");
 }

 Volume* volume_for_mount_point(const std::string& mount_point) {
   return fs_mgr_get_entry_for_mount_point(fstab, mount_point);
 }

 // Finds the volume specified by the given path. fs_mgr_get_entry_for_mount_point() does exact match
 // only, so it attempts the prefixes recursively (e.g. "/cache/recovery/last_log",
 // "/cache/recovery", "/cache", "/" for a given path of "/cache/recovery/last_log") and returns the
 // first match or nullptr.
 static Volume* volume_for_path(const char* path) {
   if (path == nullptr || path[0] == '\0') return nullptr;
   std::string str(path);
   while (true) {
     Volume* result = fs_mgr_get_entry_for_mount_point(fstab, str);
     if (result != nullptr || str == "/") {
       return result;
     }
     size_t slash = str.find_last_of('/');
     if (slash == std::string::npos) return nullptr;
     if (slash == 0) {
       str = "/";
     } else {
       str = str.substr(0, slash);
     }
   }
   return nullptr;
 }

 // Mount the volume specified by path at the given mount_point.
 int ensure_path_mounted_at(const char* path, const char* mount_point) {
   Volume* v = volume_for_path(path);
   if (v == nullptr) {
     LOG(ERROR) << "unknown volume for path [" << path << "]";
     return -1;
   }
   if (strcmp(v->fs_type, "ramdisk") == 0) {
     // The ramdisk is always mounted.
     return 0;
   }

   if (!scan_mounted_volumes()) {
     LOG(ERROR) << "Failed to scan mounted volumes";
     return -1;
   }

   if (!mount_point) {
     mount_point = v->mount_point;
   }

   const MountedVolume* mv = find_mounted_volume_by_mount_point(mount_point);
   if (mv != nullptr) {
     // Volume is already mounted.
     return 0;
   }

   mkdir(mount_point, 0755);  // in case it doesn't already exist

   if (strcmp(v->fs_type, "ext4") == 0 || strcmp(v->fs_type, "squashfs") == 0 ||
       strcmp(v->fs_type, "vfat") == 0) {
     int result = mount(v->blk_device, mount_point, v->fs_type, v->flags, v->fs_options);
     if (result == -1 && fs_mgr_is_formattable(v)) {
       PLOG(ERROR) << "Failed to mount " << mount_point << "; formatting";
       bool crypt_footer = fs_mgr_is_encryptable(v) && !strcmp(v->key_loc, "footer");
       if (fs_mgr_do_format(v, crypt_footer) == 0) {
         result = mount(v->blk_device, mount_point, v->fs_type, v->flags, v->fs_options);
       } else {
         PLOG(ERROR) << "Failed to format " << mount_point;
         return -1;
       }
     }

     if (result == -1) {
       PLOG(ERROR) << "Failed to mount " << mount_point;
       return -1;
     }
     return 0;
   }

   LOG(ERROR) << "unknown fs_type \"" << v->fs_type << "\" for " << mount_point;
   return -1;
 }

 int ensure_path_mounted(const char* path) {
   // Mount at the default mount point.
   return ensure_path_mounted_at(path, nullptr);
 }

 int ensure_path_unmounted(const char* path) {
   const Volume* v = volume_for_path(path);
   if (v == nullptr) {
     LOG(ERROR) << "unknown volume for path [" << path << "]";
     return -1;
   }
   if (strcmp(v->fs_type, "ramdisk") == 0) {
     // The ramdisk is always mounted; you can't unmount it.
     return -1;
   }

   if (!scan_mounted_volumes()) {
     LOG(ERROR) << "Failed to scan mounted volumes";
     return -1;
   }

   MountedVolume* mv = find_mounted_volume_by_mount_point(v->mount_point);
   if (mv == nullptr) {
     // Volume is already unmounted.
     return 0;
   }

   return unmount_mounted_volume(mv);
 }

 static int exec_cmd(const std::vector<std::string>& args) {
   CHECK_NE(static_cast<size_t>(0), args.size());

   std::vector<char*> argv(args.size());
   std::transform(args.cbegin(), args.cend(), argv.begin(),
                  [](const std::string& arg) { return const_cast<char*>(arg.c_str()); });
   argv.push_back(nullptr);

   pid_t child;
   if ((child = vfork()) == 0) {
     execv(argv[0], argv.data());
     _exit(EXIT_FAILURE);
   }

   int status;
   waitpid(child, &status, 0);
   if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
     LOG(ERROR) << args[0] << " failed with status " << WEXITSTATUS(status);
   }
   return WEXITSTATUS(status);
 }

 static int64_t get_file_size(int fd, uint64_t reserve_len) {
   struct stat buf;
   int ret = fstat(fd, &buf);
   if (ret) return 0;

   int64_t computed_size;
   if (S_ISREG(buf.st_mode)) {
     computed_size = buf.st_size - reserve_len;
   } else if (S_ISBLK(buf.st_mode)) {
     uint64_t block_device_size = get_block_device_size(fd);
     if (block_device_size < reserve_len ||
         block_device_size > std::numeric_limits<int64_t>::max()) {
       computed_size = 0;
     } else {
       computed_size = block_device_size - reserve_len;
     }
   } else {
     computed_size = 0;
   }

   return computed_size;
 }

 int format_volume(const char* volume, const char* directory) {
   const Volume* v = volume_for_path(volume);
   if (v == nullptr) {
     LOG(ERROR) << "unknown volume \"" << volume << "\"";
     return -1;
   }
   if (strcmp(v->fs_type, "ramdisk") == 0) {
     LOG(ERROR) << "can't format_volume \"" << volume << "\"";
     return -1;
   }
   if (strcmp(v->mount_point, volume) != 0) {
     LOG(ERROR) << "can't give path \"" << volume << "\" to format_volume";
     return -1;
   }
   if (ensure_path_unmounted(volume) != 0) {
     LOG(ERROR) << "format_volume: Failed to unmount \"" << v->mount_point << "\"";
     return -1;
   }
   if (strcmp(v->fs_type, "ext4") != 0 && strcmp(v->fs_type, "f2fs") != 0) {
     LOG(ERROR) << "format_volume: fs_type \"" << v->fs_type << "\" unsupported";
     return -1;
   }

   // If there's a key_loc that looks like a path, it should be a block device for storing encryption
   // metadata. Wipe it too.
   if (v->key_loc != nullptr && v->key_loc[0] == '/') {
     LOG(INFO) << "Wiping " << v->key_loc;
     int fd = open(v->key_loc, O_WRONLY | O_CREAT, 0644);
     if (fd == -1) {
       PLOG(ERROR) << "format_volume: Failed to open " << v->key_loc;
       return -1;
     }
     wipe_block_device(fd, get_file_size(fd));
     close(fd);
   }

   int64_t length = 0;
   if (v->length > 0) {
     length = v->length;
   } else if (v->length < 0 ||
              (v->key_loc != nullptr && strcmp(v->key_loc, "footer") == 0)) {
     android::base::unique_fd fd(open(v->blk_device, O_RDONLY));
     if (fd == -1) {
       PLOG(ERROR) << "format_volume: failed to open " << v->blk_device;
       return -1;
     }
     length =
         get_file_size(fd.get(), v->length ? -v->length : CRYPT_FOOTER_OFFSET);
     if (length <= 0) {
       LOG(ERROR) << "get_file_size: invalid size " << length << " for "
                  << v->blk_device;
       return -1;
     }
   }

   if (strcmp(v->fs_type, "ext4") == 0) {
     static constexpr int kBlockSize = 4096;
     std::vector<std::string> mke2fs_args = {
       "/sbin/mke2fs_static", "-F", "-t", "ext4", "-b", std::to_string(kBlockSize),
     };

     int raid_stride = v->logical_blk_size / kBlockSize;
     int raid_stripe_width = v->erase_blk_size / kBlockSize;
     // stride should be the max of 8KB and logical block size
     if (v->logical_blk_size != 0 && v->logical_blk_size < 8192) {
       raid_stride = 8192 / kBlockSize;
     }
     if (v->erase_blk_size != 0 && v->logical_blk_size != 0) {
       mke2fs_args.push_back("-E");
       mke2fs_args.push_back(
           android::base::StringPrintf("stride=%d,stripe-width=%d", raid_stride, raid_stripe_width));
     }
     mke2fs_args.push_back(v->blk_device);
     if (length != 0) {
       mke2fs_args.push_back(std::to_string(length / kBlockSize));
     }

     int result = exec_cmd(mke2fs_args);
     if (result == 0 && directory != nullptr) {
       std::vector<std::string> e2fsdroid_args = {
         "/sbin/e2fsdroid_static",
         "-e",
         "-f",
         directory,
         "-a",
         volume,
         v->blk_device,
       };
       result = exec_cmd(e2fsdroid_args);
     }

     if (result != 0) {
       PLOG(ERROR) << "format_volume: Failed to make ext4 on " << v->blk_device;
       return -1;
     }
     return 0;
   }

   // Has to be f2fs because we checked earlier.
   std::string cmd("/sbin/mkfs.f2fs");
   std::vector<std::string> make_f2fs_cmd = { cmd,       "-d1", "-f",    "-O",
                                              "encrypt", "-O",  "quota", v->blk_device };
   if (length >= 512) {
     make_f2fs_cmd.push_back(std::to_string(length / 512));
   }

   int result = exec_cmd(make_f2fs_cmd);
   if (result == 0 && directory != nullptr) {
     cmd = "/sbin/sload.f2fs";
     std::vector<std::string> sload_f2fs_cmd = {
       cmd, "-f", directory, "-t", volume, v->blk_device,
     };
     result = exec_cmd(sload_f2fs_cmd);
   }
   if (result != 0) {
     PLOG(ERROR) << "format_volume: Failed " << cmd << " on " << v->blk_device;
     return -1;
   }
   return 0;
 }

 int format_volume(const char* volume) {
   return format_volume(volume, nullptr);
 }

 int setup_install_mounts() {
   if (fstab == nullptr) {
     LOG(ERROR) << "can't set up install mounts: no fstab loaded";
     return -1;
   }
   for (int i = 0; i < fstab->num_entries; ++i) {
     const Volume* v = fstab->recs + i;

     // We don't want to do anything with "/".
     if (strcmp(v->mount_point, "/") == 0) {
       continue;
     }

     if (strcmp(v->mount_point, "/tmp") == 0 || strcmp(v->mount_point, "/cache") == 0) {
       if (ensure_path_mounted(v->mount_point) != 0) {
         LOG(ERROR) << "Failed to mount " << v->mount_point;
         return -1;
       }
     } else {
       if (ensure_path_unmounted(v->mount_point) != 0) {
         LOG(ERROR) << "Failed to unmount " << v->mount_point;
         return -1;
       }
     }
   }
   return 0;
 }
	/*
	* Copyright (C) 2007 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "roots.h"

	#include <ctype.h>
	#include <fcntl.h>
	#include <stdint.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/mount.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <sys/wait.h>
	#include <unistd.h>

	#include <algorithm>
	#include <string>
	#include <vector>

	#include <android-base/logging.h>
	#include <android-base/properties.h>
	#include <android-base/stringprintf.h>
	#include <android-base/unique_fd.h>
	#include <cryptfs.h>
	#include <ext4_utils/wipe.h>
	#include <fs_mgr.h>

	#include "mounts.h"

	static struct fstab* fstab = nullptr;

	extern struct selabel_handle* sehandle;

	void load_volume_table() {
	fstab = fs_mgr_read_fstab_default();
	if (!fstab) {
	LOG(ERROR) << "Failed to read default fstab";
	return;
	}

	int ret = fs_mgr_add_entry(fstab, "/tmp", "ramdisk", "ramdisk");
	if (ret == -1) {
	LOG(ERROR) << "Failed to add /tmp entry to fstab";
	fs_mgr_free_fstab(fstab);
	fstab = nullptr;
	return;
	}

	printf("recovery filesystem table\n");
	printf("=========================\n");
	for (int i = 0; i < fstab->num_entries; ++i) {
	const Volume* v = &fstab->recs[i];
	printf(" %d %s %s %s %lld\n", i, v->mount_point, v->fs_type, v->blk_device, v->length);
	}
	printf("\n");
	}

	Volume* volume_for_mount_point(const std::string& mount_point) {
	return fs_mgr_get_entry_for_mount_point(fstab, mount_point);
	}

	// Finds the volume specified by the given path. fs_mgr_get_entry_for_mount_point() does exact match
	// only, so it attempts the prefixes recursively (e.g. "/cache/recovery/last_log",
	// "/cache/recovery", "/cache", "/" for a given path of "/cache/recovery/last_log") and returns the
	// first match or nullptr.
	static Volume* volume_for_path(const char* path) {
	if (path == nullptr \|\| path[0] == '\0') return nullptr;
	std::string str(path);
	while (true) {
	Volume* result = fs_mgr_get_entry_for_mount_point(fstab, str);
	if (result != nullptr \|\| str == "/") {
	return result;
	}
	size_t slash = str.find_last_of('/');
	if (slash == std::string::npos) return nullptr;
	if (slash == 0) {
	str = "/";
	} else {
	str = str.substr(0, slash);
	}
	}
	return nullptr;
	}

	// Mount the volume specified by path at the given mount_point.
	int ensure_path_mounted_at(const char* path, const char* mount_point) {
	Volume* v = volume_for_path(path);
	if (v == nullptr) {
	LOG(ERROR) << "unknown volume for path [" << path << "]";
	return -1;
	}
	if (strcmp(v->fs_type, "ramdisk") == 0) {
	// The ramdisk is always mounted.
	return 0;
	}

	if (!scan_mounted_volumes()) {
	LOG(ERROR) << "Failed to scan mounted volumes";
	return -1;
	}

	if (!mount_point) {
	mount_point = v->mount_point;
	}

	const MountedVolume* mv = find_mounted_volume_by_mount_point(mount_point);
	if (mv != nullptr) {
	// Volume is already mounted.
	return 0;
	}

	mkdir(mount_point, 0755); // in case it doesn't already exist

	if (strcmp(v->fs_type, "ext4") == 0 \|\| strcmp(v->fs_type, "squashfs") == 0 \|\|
	strcmp(v->fs_type, "vfat") == 0) {
	int result = mount(v->blk_device, mount_point, v->fs_type, v->flags, v->fs_options);
	if (result == -1 && fs_mgr_is_formattable(v)) {
	PLOG(ERROR) << "Failed to mount " << mount_point << "; formatting";
	bool crypt_footer = fs_mgr_is_encryptable(v) && !strcmp(v->key_loc, "footer");
	if (fs_mgr_do_format(v, crypt_footer) == 0) {
	result = mount(v->blk_device, mount_point, v->fs_type, v->flags, v->fs_options);
	} else {
	PLOG(ERROR) << "Failed to format " << mount_point;
	return -1;
	}
	}

	if (result == -1) {
	PLOG(ERROR) << "Failed to mount " << mount_point;
	return -1;
	}
	return 0;
	}

	LOG(ERROR) << "unknown fs_type \"" << v->fs_type << "\" for " << mount_point;
	return -1;
	}

	int ensure_path_mounted(const char* path) {
	// Mount at the default mount point.
	return ensure_path_mounted_at(path, nullptr);
	}

	int ensure_path_unmounted(const char* path) {
	const Volume* v = volume_for_path(path);
	if (v == nullptr) {
	LOG(ERROR) << "unknown volume for path [" << path << "]";
	return -1;
	}
	if (strcmp(v->fs_type, "ramdisk") == 0) {
	// The ramdisk is always mounted; you can't unmount it.
	return -1;
	}

	if (!scan_mounted_volumes()) {
	LOG(ERROR) << "Failed to scan mounted volumes";
	return -1;
	}

	MountedVolume* mv = find_mounted_volume_by_mount_point(v->mount_point);
	if (mv == nullptr) {
	// Volume is already unmounted.
	return 0;
	}

	return unmount_mounted_volume(mv);
	}

	static int exec_cmd(const std::vector<std::string>& args) {
	CHECK_NE(static_cast<size_t>(0), args.size());

	std::vector<char*> argv(args.size());
	std::transform(args.cbegin(), args.cend(), argv.begin(),
	[](const std::string& arg) { return const_cast<char*>(arg.c_str()); });
	argv.push_back(nullptr);

	pid_t child;
	if ((child = vfork()) == 0) {
	execv(argv[0], argv.data());
	_exit(EXIT_FAILURE);
	}

	int status;
	waitpid(child, &status, 0);
	if (!WIFEXITED(status) \|\| WEXITSTATUS(status) != 0) {
	LOG(ERROR) << args[0] << " failed with status " << WEXITSTATUS(status);
	}
	return WEXITSTATUS(status);
	}

	static int64_t get_file_size(int fd, uint64_t reserve_len) {
	struct stat buf;
	int ret = fstat(fd, &buf);
	if (ret) return 0;

	int64_t computed_size;
	if (S_ISREG(buf.st_mode)) {
	computed_size = buf.st_size - reserve_len;
	} else if (S_ISBLK(buf.st_mode)) {
	uint64_t block_device_size = get_block_device_size(fd);
	if (block_device_size < reserve_len \|\|
	block_device_size > std::numeric_limits<int64_t>::max()) {
	computed_size = 0;
	} else {
	computed_size = block_device_size - reserve_len;
	}
	} else {
	computed_size = 0;
	}

	return computed_size;
	}

	int format_volume(const char* volume, const char* directory) {
	const Volume* v = volume_for_path(volume);
	if (v == nullptr) {
	LOG(ERROR) << "unknown volume \"" << volume << "\"";
	return -1;
	}
	if (strcmp(v->fs_type, "ramdisk") == 0) {
	LOG(ERROR) << "can't format_volume \"" << volume << "\"";
	return -1;
	}
	if (strcmp(v->mount_point, volume) != 0) {
	LOG(ERROR) << "can't give path \"" << volume << "\" to format_volume";
	return -1;
	}
	if (ensure_path_unmounted(volume) != 0) {
	LOG(ERROR) << "format_volume: Failed to unmount \"" << v->mount_point << "\"";
	return -1;
	}
	if (strcmp(v->fs_type, "ext4") != 0 && strcmp(v->fs_type, "f2fs") != 0) {
	LOG(ERROR) << "format_volume: fs_type \"" << v->fs_type << "\" unsupported";
	return -1;
	}

	// If there's a key_loc that looks like a path, it should be a block device for storing encryption
	// metadata. Wipe it too.
	if (v->key_loc != nullptr && v->key_loc[0] == '/') {
	LOG(INFO) << "Wiping " << v->key_loc;
	int fd = open(v->key_loc, O_WRONLY \| O_CREAT, 0644);
	if (fd == -1) {
	PLOG(ERROR) << "format_volume: Failed to open " << v->key_loc;
	return -1;
	}
	wipe_block_device(fd, get_file_size(fd));
	close(fd);
	}

	int64_t length = 0;
	if (v->length > 0) {
	length = v->length;
	} else if (v->length < 0 \|\|
	(v->key_loc != nullptr && strcmp(v->key_loc, "footer") == 0)) {
	android::base::unique_fd fd(open(v->blk_device, O_RDONLY));
	if (fd == -1) {
	PLOG(ERROR) << "format_volume: failed to open " << v->blk_device;
	return -1;
	}
	length =
	get_file_size(fd.get(), v->length ? -v->length : CRYPT_FOOTER_OFFSET);
	if (length <= 0) {
	LOG(ERROR) << "get_file_size: invalid size " << length << " for "
	<< v->blk_device;
	return -1;
	}
	}

	if (strcmp(v->fs_type, "ext4") == 0) {
	static constexpr int kBlockSize = 4096;
	std::vector<std::string> mke2fs_args = {
	"/sbin/mke2fs_static", "-F", "-t", "ext4", "-b", std::to_string(kBlockSize),
	};

	int raid_stride = v->logical_blk_size / kBlockSize;
	int raid_stripe_width = v->erase_blk_size / kBlockSize;
	// stride should be the max of 8KB and logical block size
	if (v->logical_blk_size != 0 && v->logical_blk_size < 8192) {
	raid_stride = 8192 / kBlockSize;
	}
	if (v->erase_blk_size != 0 && v->logical_blk_size != 0) {
	mke2fs_args.push_back("-E");
	mke2fs_args.push_back(
	android::base::StringPrintf("stride=%d,stripe-width=%d", raid_stride, raid_stripe_width));
	}
	mke2fs_args.push_back(v->blk_device);
	if (length != 0) {
	mke2fs_args.push_back(std::to_string(length / kBlockSize));
	}

	int result = exec_cmd(mke2fs_args);
	if (result == 0 && directory != nullptr) {
	std::vector<std::string> e2fsdroid_args = {
	"/sbin/e2fsdroid_static",
	"-e",
	"-f",
	directory,
	"-a",
	volume,
	v->blk_device,
	};
	result = exec_cmd(e2fsdroid_args);
	}

	if (result != 0) {
	PLOG(ERROR) << "format_volume: Failed to make ext4 on " << v->blk_device;
	return -1;
	}
	return 0;
	}

	// Has to be f2fs because we checked earlier.
	std::string cmd("/sbin/mkfs.f2fs");
	std::vector<std::string> make_f2fs_cmd = { cmd, "-d1", "-f", "-O",
	"encrypt", "-O", "quota", v->blk_device };
	if (length >= 512) {
	make_f2fs_cmd.push_back(std::to_string(length / 512));
	}

	int result = exec_cmd(make_f2fs_cmd);
	if (result == 0 && directory != nullptr) {
	cmd = "/sbin/sload.f2fs";
	std::vector<std::string> sload_f2fs_cmd = {
	cmd, "-f", directory, "-t", volume, v->blk_device,
	};
	result = exec_cmd(sload_f2fs_cmd);
	}
	if (result != 0) {
	PLOG(ERROR) << "format_volume: Failed " << cmd << " on " << v->blk_device;
	return -1;
	}
	return 0;
	}

	int format_volume(const char* volume) {
	return format_volume(volume, nullptr);
	}

	int setup_install_mounts() {
	if (fstab == nullptr) {
	LOG(ERROR) << "can't set up install mounts: no fstab loaded";
	return -1;
	}
	for (int i = 0; i < fstab->num_entries; ++i) {
	const Volume* v = fstab->recs + i;

	// We don't want to do anything with "/".
	if (strcmp(v->mount_point, "/") == 0) {
	continue;
	}

	if (strcmp(v->mount_point, "/tmp") == 0 \|\| strcmp(v->mount_point, "/cache") == 0) {
	if (ensure_path_mounted(v->mount_point) != 0) {
	LOG(ERROR) << "Failed to mount " << v->mount_point;
	return -1;
	}
	} else {
	if (ensure_path_unmounted(v->mount_point) != 0) {
	LOG(ERROR) << "Failed to unmount " << v->mount_point;
	return -1;
	}
	}
	}
	return 0;
	}