From 8108e2513f8342444821c179d713982fcf931e98 Mon Sep 17 00:00:00 2001 From: David Anderson Date: Wed, 28 Aug 2019 15:24:07 -0700 Subject: Refactor boot_control into a separate library. This extracts the implementation of boot_control into a new library, libboot_control. The bootctrl.default module now wraps this library. This refactoring will allow us to re-use the same implementation in HIDL. Bug: 138861550 Test: mm bootctrl.default Change-Id: Ic0558da3c2d8e6f5ebec63a497825c24b51623b7 --- boot_control/boot_control.cpp | 401 ------------------------------------------ 1 file changed, 401 deletions(-) delete mode 100644 boot_control/boot_control.cpp (limited to 'boot_control/boot_control.cpp') diff --git a/boot_control/boot_control.cpp b/boot_control/boot_control.cpp deleted file mode 100644 index ec97b6ced..000000000 --- a/boot_control/boot_control.cpp +++ /dev/null @@ -1,401 +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 -#include -#include -#include - -#include - -#include -#include -#include -#include -#include -#include -#include - -#include - -struct boot_control_private_t { - // The base struct needs to be first in the list. - boot_control_module_t base; - - // Whether this struct was initialized with data from the bootloader message - // that doesn't change until next reboot. - bool initialized; - - // The path to the misc_device as reported in the fstab. - const char* misc_device; - - // The number of slots present on the device. - unsigned int num_slots; - - // The slot where we are running from. - unsigned int current_slot; -}; - -namespace { - -// 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(boot_ctrl), offsetof(bootloader_control, crc32_le))); -} - -bool LoadBootloaderControl(const char* misc_device, bootloader_control* buffer) { - android::base::unique_fd fd(open(misc_device, 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 char* misc_device, bootloader_control* buffer) { - buffer->crc32_le = BootloaderControlLECRC(buffer); - android::base::unique_fd fd(open(misc_device, 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(const boot_control_private_t* module, - bootloader_control* boot_ctrl) { - memset(boot_ctrl, 0, sizeof(*boot_ctrl)); - - if (module->current_slot < kMaxNumSlots) { - strlcpy(boot_ctrl->slot_suffix, kSlotSuffixes[module->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 = module->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 (module->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_lazyInitialization(boot_control_private_t* module) { - if (module->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", ""); - module->current_slot = SlotSuffixToIndex(suffix_prop.c_str()); - - std::string err; - std::string device = get_bootloader_message_blk_device(&err); - if (device.empty()) return false; - - bootloader_control boot_ctrl; - if (!LoadBootloaderControl(device.c_str(), &boot_ctrl)) return false; - - // Note that since there isn't a module unload function this memory is leaked. - module->misc_device = strdup(device.c_str()); - module->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(module, &boot_ctrl); - UpdateAndSaveBootloaderControl(device.c_str(), &boot_ctrl); - } - - module->num_slots = boot_ctrl.nb_slot; - return true; -} - -void BootControl_init(boot_control_module_t* module) { - BootControl_lazyInitialization(reinterpret_cast(module)); -} - -unsigned int BootControl_getNumberSlots(boot_control_module_t* module) { - return reinterpret_cast(module)->num_slots; -} - -unsigned int BootControl_getCurrentSlot(boot_control_module_t* module) { - return reinterpret_cast(module)->current_slot; -} - -int BootControl_markBootSuccessful(boot_control_module_t* module) { - boot_control_private_t* const bootctrl_module = reinterpret_cast(module); - - bootloader_control bootctrl; - if (!LoadBootloaderControl(bootctrl_module->misc_device, &bootctrl)) return -1; - - bootctrl.slot_info[bootctrl_module->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[bootctrl_module->current_slot].tries_remaining = 1; - if (!UpdateAndSaveBootloaderControl(bootctrl_module->misc_device, &bootctrl)) return -1; - return 0; -} - -int BootControl_setActiveBootSlot(boot_control_module_t* module, unsigned int slot) { - boot_control_private_t* const bootctrl_module = reinterpret_cast(module); - - if (slot >= kMaxNumSlots || slot >= bootctrl_module->num_slots) { - // Invalid slot number. - return -1; - } - - bootloader_control bootctrl; - if (!LoadBootloaderControl(bootctrl_module->misc_device, &bootctrl)) return -1; - - // 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 < bootctrl_module->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 != bootctrl_module->current_slot) bootctrl.slot_info[slot].verity_corrupted = 0; - - if (!UpdateAndSaveBootloaderControl(bootctrl_module->misc_device, &bootctrl)) return -1; - return 0; -} - -int BootControl_setSlotAsUnbootable(struct boot_control_module* module, unsigned int slot) { - boot_control_private_t* const bootctrl_module = reinterpret_cast(module); - - if (slot >= kMaxNumSlots || slot >= bootctrl_module->num_slots) { - // Invalid slot number. - return -1; - } - - bootloader_control bootctrl; - if (!LoadBootloaderControl(bootctrl_module->misc_device, &bootctrl)) return -1; - - // 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; - if (!UpdateAndSaveBootloaderControl(bootctrl_module->misc_device, &bootctrl)) return -1; - return 0; -} - -int BootControl_isSlotBootable(struct boot_control_module* module, unsigned int slot) { - boot_control_private_t* const bootctrl_module = reinterpret_cast(module); - - if (slot >= kMaxNumSlots || slot >= bootctrl_module->num_slots) { - // Invalid slot number. - return -1; - } - - bootloader_control bootctrl; - if (!LoadBootloaderControl(bootctrl_module->misc_device, &bootctrl)) return -1; - - return bootctrl.slot_info[slot].tries_remaining; -} - -int BootControl_isSlotMarkedSuccessful(struct boot_control_module* module, unsigned int slot) { - boot_control_private_t* const bootctrl_module = reinterpret_cast(module); - - if (slot >= kMaxNumSlots || slot >= bootctrl_module->num_slots) { - // Invalid slot number. - return -1; - } - - bootloader_control bootctrl; - if (!LoadBootloaderControl(bootctrl_module->misc_device, &bootctrl)) return -1; - - return bootctrl.slot_info[slot].successful_boot && bootctrl.slot_info[slot].tries_remaining; -} - -const char* BootControl_getSuffix(boot_control_module_t* module, unsigned int slot) { - if (slot >= kMaxNumSlots || slot >= reinterpret_cast(module)->num_slots) { - return NULL; - } - return kSlotSuffixes[slot]; -} - -static int BootControl_open(const hw_module_t* module __unused, const char* id __unused, - hw_device_t** device __unused) { - /* Nothing to do currently. */ - return 0; -} - -struct hw_module_methods_t BootControl_methods = { - .open = BootControl_open, -}; - -} // namespace - -boot_control_private_t HAL_MODULE_INFO_SYM = { - .base = - { - .common = - { - .tag = HARDWARE_MODULE_TAG, - .module_api_version = BOOT_CONTROL_MODULE_API_VERSION_0_1, - .hal_api_version = HARDWARE_HAL_API_VERSION, - .id = BOOT_CONTROL_HARDWARE_MODULE_ID, - .name = "AOSP reference bootctrl HAL", - .author = "The Android Open Source Project", - .methods = &BootControl_methods, - }, - .init = BootControl_init, - .getNumberSlots = BootControl_getNumberSlots, - .getCurrentSlot = BootControl_getCurrentSlot, - .markBootSuccessful = BootControl_markBootSuccessful, - .setActiveBootSlot = BootControl_setActiveBootSlot, - .setSlotAsUnbootable = BootControl_setSlotAsUnbootable, - .isSlotBootable = BootControl_isSlotBootable, - .getSuffix = BootControl_getSuffix, - .isSlotMarkedSuccessful = BootControl_isSlotMarkedSuccessful, - }, - .initialized = false, - .misc_device = nullptr, - .num_slots = 0, - .current_slot = 0, -}; -- cgit v1.2.3