Checkpoint.cpp - SHIFTPHONES/android_system_vold - Gitiles

 /*
  * Copyright (C) 2018 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.
  */

 #define LOG_TAG "Checkpoint"
 #include "Checkpoint.h"
 #include "VoldUtil.h"

 #include <fstream>
 #include <list>
 #include <memory>
 #include <string>
 #include <vector>

 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
 #include <android-base/properties.h>
 #include <android-base/unique_fd.h>
 #include <android/hardware/boot/1.0/IBootControl.h>
 #include <cutils/android_reboot.h>
 #include <fcntl.h>
 #include <fs_mgr.h>
 #include <linux/fs.h>
 #include <mntent.h>
 #include <sys/mount.h>
 #include <sys/stat.h>

 using android::base::SetProperty;
 using android::binder::Status;
 using android::fs_mgr::Fstab;
 using android::fs_mgr::ReadDefaultFstab;
 using android::fs_mgr::ReadFstabFromFile;
 using android::hardware::hidl_string;
 using android::hardware::boot::V1_0::BoolResult;
 using android::hardware::boot::V1_0::CommandResult;
 using android::hardware::boot::V1_0::IBootControl;
 using android::hardware::boot::V1_0::Slot;

 namespace android {
 namespace vold {

 namespace {
 const std::string kMetadataCPFile = "/metadata/vold/checkpoint";

 bool setBowState(std::string const& block_device, std::string const& state) {
     if (block_device.substr(0, 5) != "/dev/") {
         LOG(ERROR) << "Expected block device, got " << block_device;
         return false;
     }

     std::string state_filename = std::string("/sys/") + block_device.substr(5) + "/bow/state";
     if (!android::base::WriteStringToFile(state, state_filename)) {
         PLOG(ERROR) << "Failed to write to file " << state_filename;
         return false;
     }

     return true;
 }

 }  // namespace

 Status cp_supportsCheckpoint(bool& result) {
     result = false;

     for (const auto& entry : fstab_default) {
         if (entry.fs_mgr_flags.checkpoint_blk || entry.fs_mgr_flags.checkpoint_fs) {
             result = true;
             return Status::ok();
         }
     }
     return Status::ok();
 }

 Status cp_startCheckpoint(int retry) {
     if (retry < -1) return Status::fromExceptionCode(EINVAL, "Retry count must be more than -1");
     std::string content = std::to_string(retry + 1);
     if (retry == -1) {
         sp<IBootControl> module = IBootControl::getService();
         if (module) {
             std::string suffix;
             auto cb = [&suffix](hidl_string s) { suffix = s; };
             if (module->getSuffix(module->getCurrentSlot(), cb).isOk()) content += " " + suffix;
         }
     }
     if (!android::base::WriteStringToFile(content, kMetadataCPFile))
         return Status::fromExceptionCode(errno, "Failed to write checkpoint file");
     return Status::ok();
 }

 namespace {

 bool isCheckpointing = false;
 }

 Status cp_commitChanges() {
     if (!isCheckpointing) {
         return Status::ok();
     }
     sp<IBootControl> module = IBootControl::getService();
     if (module) {
         CommandResult cr;
         module->markBootSuccessful([&cr](CommandResult result) { cr = result; });
         if (!cr.success) {
             std::string msg = "Error marking booted successfully: " + std::string(cr.errMsg);
             return Status::fromExceptionCode(EINVAL, String8(msg.c_str()));
         }
         LOG(INFO) << "Marked slot as booted successfully.";
     }
     // Must take action for list of mounted checkpointed things here
     // To do this, we walk the list of mounted file systems.
     // But we also need to get the matching fstab entries to see
     // the original flags
     std::string err_str;

     Fstab mounts;
     if (!ReadFstabFromFile("/proc/mounts", &mounts)) {
         return Status::fromExceptionCode(EINVAL, "Failed to get /proc/mounts");
     }

     // Walk mounted file systems
     for (const auto& mount_rec : mounts) {
         const auto fstab_rec = GetEntryForMountPoint(&fstab_default, mount_rec.mount_point);
         if (!fstab_rec) continue;

         if (fstab_rec->fs_mgr_flags.checkpoint_fs) {
             if (fstab_rec->fs_type == "f2fs") {
                 std::string options = mount_rec.fs_options + ",checkpoint=enable";
                 if (mount(mount_rec.blk_device.c_str(), mount_rec.mount_point.c_str(), "none",
                           MS_REMOUNT | fstab_rec->flags, options.c_str())) {
                     return Status::fromExceptionCode(EINVAL, "Failed to remount");
                 }
             }
         } else if (fstab_rec->fs_mgr_flags.checkpoint_blk) {
             if (!setBowState(mount_rec.blk_device, "2"))
                 return Status::fromExceptionCode(EINVAL, "Failed to set bow state");
         }
     }
     SetProperty("vold.checkpoint_committed", "1");
     LOG(INFO) << "Checkpoint has been committed.";
     isCheckpointing = false;
     if (!android::base::RemoveFileIfExists(kMetadataCPFile, &err_str))
         return Status::fromExceptionCode(errno, err_str.c_str());
     return Status::ok();
 }

 Status cp_abortChanges() {
     android_reboot(ANDROID_RB_RESTART2, 0, nullptr);
     return Status::ok();
 }

 bool cp_needsRollback() {
     std::string content;
     bool ret;

     ret = android::base::ReadFileToString(kMetadataCPFile, &content);
     if (ret) {
         if (content == "0") return true;
         if (content.substr(0, 3) == "-1 ") {
             std::string oldSuffix = content.substr(3);
             sp<IBootControl> module = IBootControl::getService();
             std::string newSuffix;

             if (module) {
                 auto cb = [&newSuffix](hidl_string s) { newSuffix = s; };
                 module->getSuffix(module->getCurrentSlot(), cb);
                 if (oldSuffix == newSuffix) return true;
             }
         }
     }
     return false;
 }

 bool cp_needsCheckpoint() {
     bool ret;
     std::string content;
     sp<IBootControl> module = IBootControl::getService();

     if (module && module->isSlotMarkedSuccessful(module->getCurrentSlot()) == BoolResult::FALSE) {
         isCheckpointing = true;
         return true;
     }
     ret = android::base::ReadFileToString(kMetadataCPFile, &content);
     if (ret) {
         ret = content != "0";
         isCheckpointing = ret;
         return ret;
     }
     return false;
 }

 Status cp_prepareCheckpoint() {
     if (!isCheckpointing) {
         return Status::ok();
     }

     Fstab mounts;
     if (!ReadFstabFromFile("/proc/mounts", &mounts)) {
         return Status::fromExceptionCode(EINVAL, "Failed to get /proc/mounts");
     }

     for (const auto& mount_rec : mounts) {
         const auto fstab_rec = GetEntryForMountPoint(&fstab_default, mount_rec.mount_point);
         if (!fstab_rec) continue;

         if (fstab_rec->fs_mgr_flags.checkpoint_blk) {
             android::base::unique_fd fd(
                 TEMP_FAILURE_RETRY(open(mount_rec.mount_point.c_str(), O_RDONLY | O_CLOEXEC)));
             if (!fd) {
                 PLOG(ERROR) << "Failed to open mount point" << mount_rec.mount_point;
                 continue;
             }

             struct fstrim_range range = {};
             range.len = ULLONG_MAX;
             if (ioctl(fd, FITRIM, &range)) {
                 PLOG(ERROR) << "Failed to trim " << mount_rec.mount_point;
                 continue;
             }

             setBowState(mount_rec.blk_device, "1");
         }
     }
     return Status::ok();
 }

 namespace {
 const int kSectorSize = 512;

 typedef uint64_t sector_t;

 struct log_entry {
     sector_t source;  // in sectors of size kSectorSize
     sector_t dest;    // in sectors of size kSectorSize
     uint32_t size;    // in bytes
     uint32_t checksum;
 } __attribute__((packed));

 struct log_sector_v1_0 {
     uint32_t magic;
     uint16_t header_version;
     uint16_t header_size;
     uint32_t block_size;
     uint32_t count;
     uint32_t sequence;
     uint64_t sector0;
 } __attribute__((packed));

 // MAGIC is BOW in ascii
 const int kMagic = 0x00574f42;

 void crc32(const void* data, size_t n_bytes, uint32_t* crc) {
     static uint32_t table[0x100] = {
         0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535,
         0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD,
         0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D,
         0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
         0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
         0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C,
         0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC,
         0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
         0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB,
         0xB6662D3D,

         0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5,
         0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D,
         0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED,
         0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
         0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074,
         0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC,
         0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C,
         0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
         0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B,
         0xC0BA6CAD,

         0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615,
         0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D,
         0x0A00AE27, 0x7D079EB1, 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D,
         0x806567CB, 0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
         0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4,
         0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C,
         0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79, 0xCB61B38C,
         0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
         0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B,
         0x5BDEAE1D,

         0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785,
         0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D,
         0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD,
         0xF6B9265B, 0x6FB077E1, 0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
         0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278, 0xD70DD2EE, 0x4E048354,
         0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC,
         0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9, 0xBDBDF21C,
         0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
         0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B,
         0x2D02EF8D};

     for (size_t i = 0; i < n_bytes; ++i) {
         *crc ^= ((uint8_t*)data)[i];
         *crc = table[(uint8_t)*crc] ^ *crc >> 8;
     }
 }

 // A map of relocations.
 // The map must be initialized so that relocations[0] = 0
 // During restore, we replay the log records in reverse, copying from dest to
 // source
 // To validate, we must be able to read the 'dest' sectors as though they had
 // been copied but without actually copying. This map represents how the sectors
 // would have been moved. To read a sector s, find the index <= s and read
 // relocations[index] + s - index
 typedef std::map<sector_t, sector_t> Relocations;

 void relocate(Relocations& relocations, sector_t dest, sector_t source, int count) {
     // Find first one we're equal to or greater than
     auto s = --relocations.upper_bound(source);

     // Take slice
     Relocations slice;
     slice[dest] = source - s->first + s->second;
     ++s;

     // Add rest of elements
     for (; s != relocations.end() && s->first < source + count; ++s)
         slice[dest - source + s->first] = s->second;

     // Split range at end of dest
     auto dest_end = --relocations.upper_bound(dest + count);
     relocations[dest + count] = dest + count - dest_end->first + dest_end->second;

     // Remove all elements in [dest, dest + count)
     relocations.erase(relocations.lower_bound(dest), relocations.lower_bound(dest + count));

     // Add new elements
     relocations.insert(slice.begin(), slice.end());
 }

 // Read from the device
 // If we are validating, the read occurs as though the relocations had happened
 std::vector<char> relocatedRead(int device_fd, Relocations const& relocations, bool validating,
                                 sector_t sector, uint32_t size, uint32_t block_size) {
     if (!validating) {
         std::vector<char> buffer(size);
         lseek64(device_fd, sector * kSectorSize, SEEK_SET);
         read(device_fd, &buffer[0], size);
         return buffer;
     }

     std::vector<char> buffer(size);
     for (uint32_t i = 0; i < size; i += block_size, sector += block_size / kSectorSize) {
         auto relocation = --relocations.upper_bound(sector);
         lseek64(device_fd, (sector + relocation->second - relocation->first) * kSectorSize,
                 SEEK_SET);
         read(device_fd, &buffer[i], block_size);
     }

     return buffer;
 }

 }  // namespace

 Status cp_restoreCheckpoint(const std::string& blockDevice, int restore_limit) {
     bool validating = true;
     std::string action = "Validating";
     int restore_count = 0;

     for (;;) {
         Relocations relocations;
         relocations[0] = 0;
         Status status = Status::ok();

         LOG(INFO) << action << " checkpoint on " << blockDevice;
         base::unique_fd device_fd(open(blockDevice.c_str(), O_RDWR));
         if (device_fd < 0) {
             PLOG(ERROR) << "Cannot open " << blockDevice;
             return Status::fromExceptionCode(errno, ("Cannot open " + blockDevice).c_str());
         }

         log_sector_v1_0 original_ls;
         read(device_fd, reinterpret_cast<char*>(&original_ls), sizeof(original_ls));
         if (original_ls.magic != kMagic) {
             LOG(ERROR) << "No magic";
             return Status::fromExceptionCode(EINVAL, "No magic");
         }

         LOG(INFO) << action << " " << original_ls.sequence << " log sectors";

         for (int sequence = original_ls.sequence; sequence >= 0 && status.isOk(); sequence--) {
             auto buffer = relocatedRead(device_fd, relocations, validating, 0,
                                         original_ls.block_size, original_ls.block_size);
             log_sector_v1_0 const& ls = *reinterpret_cast<log_sector_v1_0*>(&buffer[0]);
             if (ls.magic != kMagic) {
                 LOG(ERROR) << "No magic!";
                 status = Status::fromExceptionCode(EINVAL, "No magic");
                 break;
             }

             if (ls.block_size != original_ls.block_size) {
                 LOG(ERROR) << "Block size mismatch!";
                 status = Status::fromExceptionCode(EINVAL, "Block size mismatch");
                 break;
             }

             if ((int)ls.sequence != sequence) {
                 LOG(ERROR) << "Expecting log sector " << sequence << " but got " << ls.sequence;
                 status = Status::fromExceptionCode(
                     EINVAL, ("Expecting log sector " + std::to_string(sequence) + " but got " +
                              std::to_string(ls.sequence))
                                 .c_str());
                 break;
             }

             LOG(INFO) << action << " from log sector " << ls.sequence;

             for (log_entry* le =
                      reinterpret_cast<log_entry*>(&buffer[ls.header_size]) + ls.count - 1;
                  le >= reinterpret_cast<log_entry*>(&buffer[ls.header_size]); --le) {
                 // This is very noisy - limit to DEBUG only
                 LOG(VERBOSE) << action << " " << le->size << " bytes from sector " << le->dest
                              << " to " << le->source << " with checksum " << std::hex
                              << le->checksum;

                 auto buffer = relocatedRead(device_fd, relocations, validating, le->dest, le->size,
                                             ls.block_size);
                 uint32_t checksum = le->source / (ls.block_size / kSectorSize);
                 for (size_t i = 0; i < le->size; i += ls.block_size) {
                     crc32(&buffer[i], ls.block_size, &checksum);
                 }

                 if (le->checksum && checksum != le->checksum) {
                     LOG(ERROR) << "Checksums don't match " << std::hex << checksum;
                     status = Status::fromExceptionCode(EINVAL, "Checksums don't match");
                     break;
                 }

                 if (validating) {
                     relocate(relocations, le->source, le->dest, le->size / kSectorSize);
                 } else {
                     lseek64(device_fd, le->source * kSectorSize, SEEK_SET);
                     write(device_fd, &buffer[0], le->size);
                     restore_count++;
                     if (restore_limit && restore_count >= restore_limit) {
                         LOG(WARNING) << "Hit the test limit";
                         status = Status::fromExceptionCode(EAGAIN, "Hit the test limit");
                         break;
                     }
                 }
             }
         }

         if (!status.isOk()) {
             if (!validating) {
                 LOG(ERROR) << "Checkpoint restore failed even though checkpoint validation passed";
                 return status;
             }

             LOG(WARNING) << "Checkpoint validation failed - attempting to roll forward";
             auto buffer = relocatedRead(device_fd, relocations, false, original_ls.sector0,
                                         original_ls.block_size, original_ls.block_size);
             lseek64(device_fd, 0, SEEK_SET);
             write(device_fd, &buffer[0], original_ls.block_size);
             return Status::ok();
         }

         if (!validating) break;

         validating = false;
         action = "Restoring";
     }

     return Status::ok();
 }

 Status cp_markBootAttempt() {
     std::string oldContent, newContent;
     int retry = 0;
     struct stat st;
     int result = stat(kMetadataCPFile.c_str(), &st);

     // If the file doesn't exist, we aren't managing a checkpoint retry counter
     if (result != 0) return Status::ok();
     if (!android::base::ReadFileToString(kMetadataCPFile, &oldContent)) {
         PLOG(ERROR) << "Failed to read checkpoint file";
         return Status::fromExceptionCode(errno, "Failed to read checkpoint file");
     }
     std::string retryContent = oldContent.substr(0, oldContent.find_first_of(" "));

     if (!android::base::ParseInt(retryContent, &retry))
         return Status::fromExceptionCode(EINVAL, "Could not parse retry count");
     if (retry > 0) {
         retry--;

         newContent = std::to_string(retry);
         if (!android::base::WriteStringToFile(newContent, kMetadataCPFile))
             return Status::fromExceptionCode(errno, "Could not write checkpoint file");
     }
     return Status::ok();
 }

 }  // namespace vold
 }  // namespace android
	/*
	* Copyright (C) 2018 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.
	*/

	#define LOG_TAG "Checkpoint"
	#include "Checkpoint.h"
	#include "VoldUtil.h"

	#include <fstream>
	#include <list>
	#include <memory>
	#include <string>
	#include <vector>

	#include <android-base/file.h>
	#include <android-base/logging.h>
	#include <android-base/parseint.h>
	#include <android-base/properties.h>
	#include <android-base/unique_fd.h>
	#include <android/hardware/boot/1.0/IBootControl.h>
	#include <cutils/android_reboot.h>
	#include <fcntl.h>
	#include <fs_mgr.h>
	#include <linux/fs.h>
	#include <mntent.h>
	#include <sys/mount.h>
	#include <sys/stat.h>

	using android::base::SetProperty;
	using android::binder::Status;
	using android::fs_mgr::Fstab;
	using android::fs_mgr::ReadDefaultFstab;
	using android::fs_mgr::ReadFstabFromFile;
	using android::hardware::hidl_string;
	using android::hardware::boot::V1_0::BoolResult;
	using android::hardware::boot::V1_0::CommandResult;
	using android::hardware::boot::V1_0::IBootControl;
	using android::hardware::boot::V1_0::Slot;

	namespace android {
	namespace vold {

	namespace {
	const std::string kMetadataCPFile = "/metadata/vold/checkpoint";

	bool setBowState(std::string const& block_device, std::string const& state) {
	if (block_device.substr(0, 5) != "/dev/") {
	LOG(ERROR) << "Expected block device, got " << block_device;
	return false;
	}

	std::string state_filename = std::string("/sys/") + block_device.substr(5) + "/bow/state";
	if (!android::base::WriteStringToFile(state, state_filename)) {
	PLOG(ERROR) << "Failed to write to file " << state_filename;
	return false;
	}

	return true;
	}

	} // namespace

	Status cp_supportsCheckpoint(bool& result) {
	result = false;

	for (const auto& entry : fstab_default) {
	if (entry.fs_mgr_flags.checkpoint_blk \|\| entry.fs_mgr_flags.checkpoint_fs) {
	result = true;
	return Status::ok();
	}
	}
	return Status::ok();
	}

	Status cp_startCheckpoint(int retry) {
	if (retry < -1) return Status::fromExceptionCode(EINVAL, "Retry count must be more than -1");
	std::string content = std::to_string(retry + 1);
	if (retry == -1) {
	sp<IBootControl> module = IBootControl::getService();
	if (module) {
	std::string suffix;
	auto cb = [&suffix](hidl_string s) { suffix = s; };
	if (module->getSuffix(module->getCurrentSlot(), cb).isOk()) content += " " + suffix;
	}
	}
	if (!android::base::WriteStringToFile(content, kMetadataCPFile))
	return Status::fromExceptionCode(errno, "Failed to write checkpoint file");
	return Status::ok();
	}

	namespace {

	bool isCheckpointing = false;
	}

	Status cp_commitChanges() {
	if (!isCheckpointing) {
	return Status::ok();
	}
	sp<IBootControl> module = IBootControl::getService();
	if (module) {
	CommandResult cr;
	module->markBootSuccessful([&cr](CommandResult result) { cr = result; });
	if (!cr.success) {
	std::string msg = "Error marking booted successfully: " + std::string(cr.errMsg);
	return Status::fromExceptionCode(EINVAL, String8(msg.c_str()));
	}
	LOG(INFO) << "Marked slot as booted successfully.";
	}
	// Must take action for list of mounted checkpointed things here
	// To do this, we walk the list of mounted file systems.
	// But we also need to get the matching fstab entries to see
	// the original flags
	std::string err_str;

	Fstab mounts;
	if (!ReadFstabFromFile("/proc/mounts", &mounts)) {
	return Status::fromExceptionCode(EINVAL, "Failed to get /proc/mounts");
	}

	// Walk mounted file systems
	for (const auto& mount_rec : mounts) {
	const auto fstab_rec = GetEntryForMountPoint(&fstab_default, mount_rec.mount_point);
	if (!fstab_rec) continue;

	if (fstab_rec->fs_mgr_flags.checkpoint_fs) {
	if (fstab_rec->fs_type == "f2fs") {
	std::string options = mount_rec.fs_options + ",checkpoint=enable";
	if (mount(mount_rec.blk_device.c_str(), mount_rec.mount_point.c_str(), "none",
	MS_REMOUNT \| fstab_rec->flags, options.c_str())) {
	return Status::fromExceptionCode(EINVAL, "Failed to remount");
	}
	}
	} else if (fstab_rec->fs_mgr_flags.checkpoint_blk) {
	if (!setBowState(mount_rec.blk_device, "2"))
	return Status::fromExceptionCode(EINVAL, "Failed to set bow state");
	}
	}
	SetProperty("vold.checkpoint_committed", "1");
	LOG(INFO) << "Checkpoint has been committed.";
	isCheckpointing = false;
	if (!android::base::RemoveFileIfExists(kMetadataCPFile, &err_str))
	return Status::fromExceptionCode(errno, err_str.c_str());
	return Status::ok();
	}

	Status cp_abortChanges() {
	android_reboot(ANDROID_RB_RESTART2, 0, nullptr);
	return Status::ok();
	}

	bool cp_needsRollback() {
	std::string content;
	bool ret;

	ret = android::base::ReadFileToString(kMetadataCPFile, &content);
	if (ret) {
	if (content == "0") return true;
	if (content.substr(0, 3) == "-1 ") {
	std::string oldSuffix = content.substr(3);
	sp<IBootControl> module = IBootControl::getService();
	std::string newSuffix;

	if (module) {
	auto cb = [&newSuffix](hidl_string s) { newSuffix = s; };
	module->getSuffix(module->getCurrentSlot(), cb);
	if (oldSuffix == newSuffix) return true;
	}
	}
	}
	return false;
	}

	bool cp_needsCheckpoint() {
	bool ret;
	std::string content;
	sp<IBootControl> module = IBootControl::getService();

	if (module && module->isSlotMarkedSuccessful(module->getCurrentSlot()) == BoolResult::FALSE) {
	isCheckpointing = true;
	return true;
	}
	ret = android::base::ReadFileToString(kMetadataCPFile, &content);
	if (ret) {
	ret = content != "0";
	isCheckpointing = ret;
	return ret;
	}
	return false;
	}

	Status cp_prepareCheckpoint() {
	if (!isCheckpointing) {
	return Status::ok();
	}

	Fstab mounts;
	if (!ReadFstabFromFile("/proc/mounts", &mounts)) {
	return Status::fromExceptionCode(EINVAL, "Failed to get /proc/mounts");
	}

	for (const auto& mount_rec : mounts) {
	const auto fstab_rec = GetEntryForMountPoint(&fstab_default, mount_rec.mount_point);
	if (!fstab_rec) continue;

	if (fstab_rec->fs_mgr_flags.checkpoint_blk) {
	android::base::unique_fd fd(
	TEMP_FAILURE_RETRY(open(mount_rec.mount_point.c_str(), O_RDONLY \| O_CLOEXEC)));
	if (!fd) {
	PLOG(ERROR) << "Failed to open mount point" << mount_rec.mount_point;
	continue;
	}

	struct fstrim_range range = {};
	range.len = ULLONG_MAX;
	if (ioctl(fd, FITRIM, &range)) {
	PLOG(ERROR) << "Failed to trim " << mount_rec.mount_point;
	continue;
	}

	setBowState(mount_rec.blk_device, "1");
	}
	}
	return Status::ok();
	}

	namespace {
	const int kSectorSize = 512;

	typedef uint64_t sector_t;

	struct log_entry {
	sector_t source; // in sectors of size kSectorSize
	sector_t dest; // in sectors of size kSectorSize
	uint32_t size; // in bytes
	uint32_t checksum;
	} __attribute__((packed));

	struct log_sector_v1_0 {
	uint32_t magic;
	uint16_t header_version;
	uint16_t header_size;
	uint32_t block_size;
	uint32_t count;
	uint32_t sequence;
	uint64_t sector0;
	} __attribute__((packed));

	// MAGIC is BOW in ascii
	const int kMagic = 0x00574f42;

	void crc32(const void* data, size_t n_bytes, uint32_t* crc) {
	static uint32_t table[0x100] = {
	0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535,
	0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD,
	0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D,
	0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
	0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
	0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C,
	0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC,
	0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
	0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB,
	0xB6662D3D,

	0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5,
	0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D,
	0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED,
	0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
	0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074,
	0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC,
	0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C,
	0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
	0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B,
	0xC0BA6CAD,

	0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615,
	0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D,
	0x0A00AE27, 0x7D079EB1, 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D,
	0x806567CB, 0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
	0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4,
	0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C,
	0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79, 0xCB61B38C,
	0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
	0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B,
	0x5BDEAE1D,

	0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785,
	0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D,
	0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD,
	0xF6B9265B, 0x6FB077E1, 0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
	0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278, 0xD70DD2EE, 0x4E048354,
	0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC,
	0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9, 0xBDBDF21C,
	0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
	0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B,
	0x2D02EF8D};

	for (size_t i = 0; i < n_bytes; ++i) {
	crc ^= ((uint8_t)data)[i];
	crc = table[(uint8_t)crc] ^ *crc >> 8;
	}
	}

	// A map of relocations.
	// The map must be initialized so that relocations[0] = 0
	// During restore, we replay the log records in reverse, copying from dest to
	// source
	// To validate, we must be able to read the 'dest' sectors as though they had
	// been copied but without actually copying. This map represents how the sectors
	// would have been moved. To read a sector s, find the index <= s and read
	// relocations[index] + s - index
	typedef std::map<sector_t, sector_t> Relocations;

	void relocate(Relocations& relocations, sector_t dest, sector_t source, int count) {
	// Find first one we're equal to or greater than
	auto s = --relocations.upper_bound(source);

	// Take slice
	Relocations slice;
	slice[dest] = source - s->first + s->second;
	++s;

	// Add rest of elements
	for (; s != relocations.end() && s->first < source + count; ++s)
	slice[dest - source + s->first] = s->second;

	// Split range at end of dest
	auto dest_end = --relocations.upper_bound(dest + count);
	relocations[dest + count] = dest + count - dest_end->first + dest_end->second;

	// Remove all elements in [dest, dest + count)
	relocations.erase(relocations.lower_bound(dest), relocations.lower_bound(dest + count));

	// Add new elements
	relocations.insert(slice.begin(), slice.end());
	}

	// Read from the device
	// If we are validating, the read occurs as though the relocations had happened
	std::vector<char> relocatedRead(int device_fd, Relocations const& relocations, bool validating,
	sector_t sector, uint32_t size, uint32_t block_size) {
	if (!validating) {
	std::vector<char> buffer(size);
	lseek64(device_fd, sector * kSectorSize, SEEK_SET);
	read(device_fd, &buffer[0], size);
	return buffer;
	}

	std::vector<char> buffer(size);
	for (uint32_t i = 0; i < size; i += block_size, sector += block_size / kSectorSize) {
	auto relocation = --relocations.upper_bound(sector);
	lseek64(device_fd, (sector + relocation->second - relocation->first) * kSectorSize,
	SEEK_SET);
	read(device_fd, &buffer[i], block_size);
	}

	return buffer;
	}

	} // namespace

	Status cp_restoreCheckpoint(const std::string& blockDevice, int restore_limit) {
	bool validating = true;
	std::string action = "Validating";
	int restore_count = 0;

	for (;;) {
	Relocations relocations;
	relocations[0] = 0;
	Status status = Status::ok();

	LOG(INFO) << action << " checkpoint on " << blockDevice;
	base::unique_fd device_fd(open(blockDevice.c_str(), O_RDWR));
	if (device_fd < 0) {
	PLOG(ERROR) << "Cannot open " << blockDevice;
	return Status::fromExceptionCode(errno, ("Cannot open " + blockDevice).c_str());
	}

	log_sector_v1_0 original_ls;
	read(device_fd, reinterpret_cast<char*>(&original_ls), sizeof(original_ls));
	if (original_ls.magic != kMagic) {
	LOG(ERROR) << "No magic";
	return Status::fromExceptionCode(EINVAL, "No magic");
	}

	LOG(INFO) << action << " " << original_ls.sequence << " log sectors";

	for (int sequence = original_ls.sequence; sequence >= 0 && status.isOk(); sequence--) {
	auto buffer = relocatedRead(device_fd, relocations, validating, 0,
	original_ls.block_size, original_ls.block_size);
	log_sector_v1_0 const& ls = reinterpret_cast<log_sector_v1_0>(&buffer[0]);
	if (ls.magic != kMagic) {
	LOG(ERROR) << "No magic!";
	status = Status::fromExceptionCode(EINVAL, "No magic");
	break;
	}

	if (ls.block_size != original_ls.block_size) {
	LOG(ERROR) << "Block size mismatch!";
	status = Status::fromExceptionCode(EINVAL, "Block size mismatch");
	break;
	}

	if ((int)ls.sequence != sequence) {
	LOG(ERROR) << "Expecting log sector " << sequence << " but got " << ls.sequence;
	status = Status::fromExceptionCode(
	EINVAL, ("Expecting log sector " + std::to_string(sequence) + " but got " +
	std::to_string(ls.sequence))
	.c_str());
	break;
	}

	LOG(INFO) << action << " from log sector " << ls.sequence;

	for (log_entry* le =
	reinterpret_cast<log_entry*>(&buffer[ls.header_size]) + ls.count - 1;
	le >= reinterpret_cast<log_entry*>(&buffer[ls.header_size]); --le) {
	// This is very noisy - limit to DEBUG only
	LOG(VERBOSE) << action << " " << le->size << " bytes from sector " << le->dest
	<< " to " << le->source << " with checksum " << std::hex
	<< le->checksum;

	auto buffer = relocatedRead(device_fd, relocations, validating, le->dest, le->size,
	ls.block_size);
	uint32_t checksum = le->source / (ls.block_size / kSectorSize);
	for (size_t i = 0; i < le->size; i += ls.block_size) {
	crc32(&buffer[i], ls.block_size, &checksum);
	}

	if (le->checksum && checksum != le->checksum) {
	LOG(ERROR) << "Checksums don't match " << std::hex << checksum;
	status = Status::fromExceptionCode(EINVAL, "Checksums don't match");
	break;
	}

	if (validating) {
	relocate(relocations, le->source, le->dest, le->size / kSectorSize);
	} else {
	lseek64(device_fd, le->source * kSectorSize, SEEK_SET);
	write(device_fd, &buffer[0], le->size);
	restore_count++;
	if (restore_limit && restore_count >= restore_limit) {
	LOG(WARNING) << "Hit the test limit";
	status = Status::fromExceptionCode(EAGAIN, "Hit the test limit");
	break;
	}
	}
	}
	}

	if (!status.isOk()) {
	if (!validating) {
	LOG(ERROR) << "Checkpoint restore failed even though checkpoint validation passed";
	return status;
	}

	LOG(WARNING) << "Checkpoint validation failed - attempting to roll forward";
	auto buffer = relocatedRead(device_fd, relocations, false, original_ls.sector0,
	original_ls.block_size, original_ls.block_size);
	lseek64(device_fd, 0, SEEK_SET);
	write(device_fd, &buffer[0], original_ls.block_size);
	return Status::ok();
	}

	if (!validating) break;

	validating = false;
	action = "Restoring";
	}

	return Status::ok();
	}

	Status cp_markBootAttempt() {
	std::string oldContent, newContent;
	int retry = 0;
	struct stat st;
	int result = stat(kMetadataCPFile.c_str(), &st);

	// If the file doesn't exist, we aren't managing a checkpoint retry counter
	if (result != 0) return Status::ok();
	if (!android::base::ReadFileToString(kMetadataCPFile, &oldContent)) {
	PLOG(ERROR) << "Failed to read checkpoint file";
	return Status::fromExceptionCode(errno, "Failed to read checkpoint file");
	}
	std::string retryContent = oldContent.substr(0, oldContent.find_first_of(" "));

	if (!android::base::ParseInt(retryContent, &retry))
	return Status::fromExceptionCode(EINVAL, "Could not parse retry count");
	if (retry > 0) {
	retry--;

	newContent = std::to_string(retry);
	if (!android::base::WriteStringToFile(newContent, kMetadataCPFile))
	return Status::fromExceptionCode(errno, "Could not write checkpoint file");
	}
	return Status::ok();
	}

	} // namespace vold
	} // namespace android