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Diffstat (limited to 'boot_control/libboot_control.cpp')
| -rw-r--r-- | boot_control/libboot_control.cpp | 424 |
1 files changed, 0 insertions, 424 deletions
diff --git a/boot_control/libboot_control.cpp b/boot_control/libboot_control.cpp deleted file mode 100644 index ab9ce971b..000000000 --- a/boot_control/libboot_control.cpp +++ /dev/null @@ -1,424 +0,0 @@ -/* - * Copyright (C) 2015 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 <libboot_control/libboot_control.h> - -#include <endian.h> -#include <errno.h> -#include <fcntl.h> -#include <string.h> - -#include <string> - -#include <android-base/file.h> -#include <android-base/logging.h> -#include <android-base/properties.h> -#include <android-base/stringprintf.h> -#include <android-base/unique_fd.h> - -#include <bootloader_message/bootloader_message.h> - -namespace android { -namespace bootable { - -using ::android::hardware::boot::V1_1::MergeStatus; - -// The number of boot attempts that should be made from a new slot before -// rolling back to the previous slot. -constexpr unsigned int kDefaultBootAttempts = 7; -static_assert(kDefaultBootAttempts < 8, "tries_remaining field only has 3 bits"); - -constexpr unsigned int kMaxNumSlots = - sizeof(bootloader_control::slot_info) / sizeof(bootloader_control::slot_info[0]); -constexpr const char* kSlotSuffixes[kMaxNumSlots] = { "_a", "_b", "_c", "_d" }; -constexpr off_t kBootloaderControlOffset = offsetof(bootloader_message_ab, slot_suffix); - -static uint32_t CRC32(const uint8_t* buf, size_t size) { - static uint32_t crc_table[256]; - - // Compute the CRC-32 table only once. - if (!crc_table[1]) { - for (uint32_t i = 0; i < 256; ++i) { - uint32_t crc = i; - for (uint32_t j = 0; j < 8; ++j) { - uint32_t mask = -(crc & 1); - crc = (crc >> 1) ^ (0xEDB88320 & mask); - } - crc_table[i] = crc; - } - } - - uint32_t ret = -1; - for (size_t i = 0; i < size; ++i) { - ret = (ret >> 8) ^ crc_table[(ret ^ buf[i]) & 0xFF]; - } - - return ~ret; -} - -// Return the little-endian representation of the CRC-32 of the first fields -// in |boot_ctrl| up to the crc32_le field. -uint32_t BootloaderControlLECRC(const bootloader_control* boot_ctrl) { - return htole32( - CRC32(reinterpret_cast<const uint8_t*>(boot_ctrl), offsetof(bootloader_control, crc32_le))); -} - -bool LoadBootloaderControl(const std::string& misc_device, bootloader_control* buffer) { - android::base::unique_fd fd(open(misc_device.c_str(), O_RDONLY)); - if (fd.get() == -1) { - PLOG(ERROR) << "failed to open " << misc_device; - return false; - } - if (lseek(fd, kBootloaderControlOffset, SEEK_SET) != kBootloaderControlOffset) { - PLOG(ERROR) << "failed to lseek " << misc_device; - return false; - } - if (!android::base::ReadFully(fd.get(), buffer, sizeof(bootloader_control))) { - PLOG(ERROR) << "failed to read " << misc_device; - return false; - } - return true; -} - -bool UpdateAndSaveBootloaderControl(const std::string& misc_device, bootloader_control* buffer) { - buffer->crc32_le = BootloaderControlLECRC(buffer); - android::base::unique_fd fd(open(misc_device.c_str(), O_WRONLY | O_SYNC)); - if (fd.get() == -1) { - PLOG(ERROR) << "failed to open " << misc_device; - return false; - } - if (lseek(fd.get(), kBootloaderControlOffset, SEEK_SET) != kBootloaderControlOffset) { - PLOG(ERROR) << "failed to lseek " << misc_device; - return false; - } - if (!android::base::WriteFully(fd.get(), buffer, sizeof(bootloader_control))) { - PLOG(ERROR) << "failed to write " << misc_device; - return false; - } - return true; -} - -void InitDefaultBootloaderControl(BootControl* control, bootloader_control* boot_ctrl) { - memset(boot_ctrl, 0, sizeof(*boot_ctrl)); - - unsigned int current_slot = control->GetCurrentSlot(); - if (current_slot < kMaxNumSlots) { - strlcpy(boot_ctrl->slot_suffix, kSlotSuffixes[current_slot], sizeof(boot_ctrl->slot_suffix)); - } - boot_ctrl->magic = BOOT_CTRL_MAGIC; - boot_ctrl->version = BOOT_CTRL_VERSION; - - // Figure out the number of slots by checking if the partitions exist, - // otherwise assume the maximum supported by the header. - boot_ctrl->nb_slot = kMaxNumSlots; - std::string base_path = control->misc_device(); - size_t last_path_sep = base_path.rfind('/'); - if (last_path_sep != std::string::npos) { - // We test the existence of the "boot" partition on each possible slot, - // which is a partition required by Android Bootloader Requirements. - base_path = base_path.substr(0, last_path_sep + 1) + "boot"; - int last_existing_slot = -1; - int first_missing_slot = -1; - for (unsigned int slot = 0; slot < kMaxNumSlots; ++slot) { - std::string partition_path = base_path + kSlotSuffixes[slot]; - struct stat part_stat; - int err = stat(partition_path.c_str(), &part_stat); - if (!err) { - last_existing_slot = slot; - LOG(INFO) << "Found slot: " << kSlotSuffixes[slot]; - } else if (err < 0 && errno == ENOENT && first_missing_slot == -1) { - first_missing_slot = slot; - } - } - // We only declare that we found the actual number of slots if we found all - // the boot partitions up to the number of slots, and no boot partition - // after that. Not finding any of the boot partitions implies a problem so - // we just leave the number of slots in the maximum value. - if ((last_existing_slot != -1 && last_existing_slot + 1 == first_missing_slot) || - (first_missing_slot == -1 && last_existing_slot + 1 == kMaxNumSlots)) { - boot_ctrl->nb_slot = last_existing_slot + 1; - LOG(INFO) << "Found a system with " << last_existing_slot + 1 << " slots."; - } - } - - for (unsigned int slot = 0; slot < kMaxNumSlots; ++slot) { - slot_metadata entry = {}; - - if (slot < boot_ctrl->nb_slot) { - entry.priority = 7; - entry.tries_remaining = kDefaultBootAttempts; - entry.successful_boot = 0; - } else { - entry.priority = 0; // Unbootable - } - - // When the boot_control stored on disk is invalid, we assume that the - // current slot is successful. The bootloader should repair this situation - // before booting and write a valid boot_control slot, so if we reach this - // stage it means that the misc partition was corrupted since boot. - if (current_slot == slot) { - entry.successful_boot = 1; - } - - boot_ctrl->slot_info[slot] = entry; - } - boot_ctrl->recovery_tries_remaining = 0; - - boot_ctrl->crc32_le = BootloaderControlLECRC(boot_ctrl); -} - -// Return the index of the slot suffix passed or -1 if not a valid slot suffix. -int SlotSuffixToIndex(const char* suffix) { - for (unsigned int slot = 0; slot < kMaxNumSlots; ++slot) { - if (!strcmp(kSlotSuffixes[slot], suffix)) return slot; - } - return -1; -} - -// Initialize the boot_control_private struct with the information from -// the bootloader_message buffer stored in |boot_ctrl|. Returns whether the -// initialization succeeded. -bool BootControl::Init() { - if (initialized_) return true; - - // Initialize the current_slot from the read-only property. If the property - // was not set (from either the command line or the device tree), we can later - // initialize it from the bootloader_control struct. - std::string suffix_prop = android::base::GetProperty("ro.boot.slot_suffix", ""); - if (suffix_prop.empty()) { - LOG(ERROR) << "Slot suffix property is not set"; - return false; - } - current_slot_ = SlotSuffixToIndex(suffix_prop.c_str()); - - std::string err; - std::string device = get_bootloader_message_blk_device(&err); - if (device.empty()) { - LOG(ERROR) << "Could not find bootloader message block device: " << err; - return false; - } - - bootloader_control boot_ctrl; - if (!LoadBootloaderControl(device.c_str(), &boot_ctrl)) { - LOG(ERROR) << "Failed to load bootloader control block"; - return false; - } - - // Note that since there isn't a module unload function this memory is leaked. - // We use `device` below sometimes, so it's not moved out of here. - misc_device_ = device; - initialized_ = true; - - // Validate the loaded data, otherwise we will destroy it and re-initialize it - // with the current information. - uint32_t computed_crc32 = BootloaderControlLECRC(&boot_ctrl); - if (boot_ctrl.crc32_le != computed_crc32) { - LOG(WARNING) << "Invalid boot control found, expected CRC-32 0x" << std::hex << computed_crc32 - << " but found 0x" << std::hex << boot_ctrl.crc32_le << ". Re-initializing."; - InitDefaultBootloaderControl(this, &boot_ctrl); - UpdateAndSaveBootloaderControl(device.c_str(), &boot_ctrl); - } - - if (!InitMiscVirtualAbMessageIfNeeded()) { - return false; - } - - num_slots_ = boot_ctrl.nb_slot; - return true; -} - -unsigned int BootControl::GetNumberSlots() { - return num_slots_; -} - -unsigned int BootControl::GetCurrentSlot() { - return current_slot_; -} - -bool BootControl::MarkBootSuccessful() { - bootloader_control bootctrl; - if (!LoadBootloaderControl(misc_device_, &bootctrl)) return false; - - bootctrl.slot_info[current_slot_].successful_boot = 1; - // tries_remaining == 0 means that the slot is not bootable anymore, make - // sure we mark the current slot as bootable if it succeeds in the last - // attempt. - bootctrl.slot_info[current_slot_].tries_remaining = 1; - return UpdateAndSaveBootloaderControl(misc_device_, &bootctrl); -} - -bool BootControl::SetActiveBootSlot(unsigned int slot) { - if (slot >= kMaxNumSlots || slot >= num_slots_) { - // Invalid slot number. - return false; - } - - bootloader_control bootctrl; - if (!LoadBootloaderControl(misc_device_, &bootctrl)) return false; - - // Set every other slot with a lower priority than the new "active" slot. - const unsigned int kActivePriority = 15; - const unsigned int kActiveTries = 6; - for (unsigned int i = 0; i < num_slots_; ++i) { - if (i != slot) { - if (bootctrl.slot_info[i].priority >= kActivePriority) - bootctrl.slot_info[i].priority = kActivePriority - 1; - } - } - - // Note that setting a slot as active doesn't change the successful bit. - // The successful bit will only be changed by setSlotAsUnbootable(). - bootctrl.slot_info[slot].priority = kActivePriority; - bootctrl.slot_info[slot].tries_remaining = kActiveTries; - - // Setting the current slot as active is a way to revert the operation that - // set *another* slot as active at the end of an updater. This is commonly - // used to cancel the pending update. We should only reset the verity_corrpted - // bit when attempting a new slot, otherwise the verity bit on the current - // slot would be flip. - if (slot != current_slot_) bootctrl.slot_info[slot].verity_corrupted = 0; - - return UpdateAndSaveBootloaderControl(misc_device_, &bootctrl); -} - -bool BootControl::SetSlotAsUnbootable(unsigned int slot) { - if (slot >= kMaxNumSlots || slot >= num_slots_) { - // Invalid slot number. - return false; - } - - bootloader_control bootctrl; - if (!LoadBootloaderControl(misc_device_, &bootctrl)) return false; - - // The only way to mark a slot as unbootable, regardless of the priority is to - // set the tries_remaining to 0. - bootctrl.slot_info[slot].successful_boot = 0; - bootctrl.slot_info[slot].tries_remaining = 0; - return UpdateAndSaveBootloaderControl(misc_device_, &bootctrl); -} - -bool BootControl::IsSlotBootable(unsigned int slot) { - if (slot >= kMaxNumSlots || slot >= num_slots_) { - // Invalid slot number. - return false; - } - - bootloader_control bootctrl; - if (!LoadBootloaderControl(misc_device_, &bootctrl)) return false; - - return bootctrl.slot_info[slot].tries_remaining != 0; -} - -bool BootControl::IsSlotMarkedSuccessful(unsigned int slot) { - if (slot >= kMaxNumSlots || slot >= num_slots_) { - // Invalid slot number. - return false; - } - - bootloader_control bootctrl; - if (!LoadBootloaderControl(misc_device_, &bootctrl)) return false; - - return bootctrl.slot_info[slot].successful_boot && bootctrl.slot_info[slot].tries_remaining; -} - -bool BootControl::IsValidSlot(unsigned int slot) { - return slot < kMaxNumSlots && slot < num_slots_; -} - -bool BootControl::SetSnapshotMergeStatus(MergeStatus status) { - return SetMiscVirtualAbMergeStatus(current_slot_, status); -} - -MergeStatus BootControl::GetSnapshotMergeStatus() { - MergeStatus status; - if (!GetMiscVirtualAbMergeStatus(current_slot_, &status)) { - return MergeStatus::UNKNOWN; - } - return status; -} - -const char* BootControl::GetSuffix(unsigned int slot) { - if (slot >= kMaxNumSlots || slot >= num_slots_) { - return nullptr; - } - return kSlotSuffixes[slot]; -} - -bool InitMiscVirtualAbMessageIfNeeded() { - std::string err; - misc_virtual_ab_message message; - if (!ReadMiscVirtualAbMessage(&message, &err)) { - LOG(ERROR) << "Could not read merge status: " << err; - return false; - } - - if (message.version == MISC_VIRTUAL_AB_MESSAGE_VERSION && - message.magic == MISC_VIRTUAL_AB_MAGIC_HEADER) { - // Already initialized. - return true; - } - - message = {}; - message.version = MISC_VIRTUAL_AB_MESSAGE_VERSION; - message.magic = MISC_VIRTUAL_AB_MAGIC_HEADER; - if (!WriteMiscVirtualAbMessage(message, &err)) { - LOG(ERROR) << "Could not write merge status: " << err; - return false; - } - return true; -} - -bool SetMiscVirtualAbMergeStatus(unsigned int current_slot, - android::hardware::boot::V1_1::MergeStatus status) { - std::string err; - misc_virtual_ab_message message; - - if (!ReadMiscVirtualAbMessage(&message, &err)) { - LOG(ERROR) << "Could not read merge status: " << err; - return false; - } - - message.merge_status = static_cast<uint8_t>(status); - message.source_slot = current_slot; - if (!WriteMiscVirtualAbMessage(message, &err)) { - LOG(ERROR) << "Could not write merge status: " << err; - return false; - } - return true; -} - -bool GetMiscVirtualAbMergeStatus(unsigned int current_slot, - android::hardware::boot::V1_1::MergeStatus* status) { - std::string err; - misc_virtual_ab_message message; - - if (!ReadMiscVirtualAbMessage(&message, &err)) { - LOG(ERROR) << "Could not read merge status: " << err; - return false; - } - - // If the slot reverted after having created a snapshot, then the snapshot will - // be thrown away at boot. Thus we don't count this as being in a snapshotted - // state. - *status = static_cast<MergeStatus>(message.merge_status); - if (*status == MergeStatus::SNAPSHOTTED && current_slot == message.source_slot) { - *status = MergeStatus::NONE; - } - return true; -} - -} // namespace bootable -} // namespace android |