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/Android.bp | 32 +- boot_control/boot_control.cpp | 401 --------------------- .../include/libboot_control/libboot_control.h | 58 +++ boot_control/legacy_boot_control.cpp | 115 ++++++ boot_control/libboot_control.cpp | 328 +++++++++++++++++ 5 files changed, 528 insertions(+), 406 deletions(-) delete mode 100644 boot_control/boot_control.cpp create mode 100644 boot_control/include/libboot_control/libboot_control.h create mode 100644 boot_control/legacy_boot_control.cpp create mode 100644 boot_control/libboot_control.cpp diff --git a/boot_control/Android.bp b/boot_control/Android.bp index 7720ead50..0ebce85ea 100644 --- a/boot_control/Android.bp +++ b/boot_control/Android.bp @@ -14,13 +14,11 @@ // limitations under the License. // -cc_library_shared { - name: "bootctrl.default", +cc_defaults { + name: "libboot_control_defaults", recovery_available: true, relative_install_path: "hw", - srcs: ["boot_control.cpp"], - cflags: [ "-D_FILE_OFFSET_BITS=64", "-Werror", @@ -31,7 +29,31 @@ cc_library_shared { shared_libs: [ "libbase", "libbootloader_message", - "libfs_mgr", "liblog", ], + static_libs: [ + "libfstab", + ], +} + +cc_library_static { + name: "libboot_control", + defaults: ["libboot_control_defaults"], + export_include_dirs: ["include"], + + srcs: ["libboot_control.cpp"], +} + +cc_library_shared { + name: "bootctrl.default", + defaults: ["libboot_control_defaults"], + + srcs: ["legacy_boot_control.cpp"], + + static_libs: [ + "libboot_control", + ], + shared_libs: [ + "libhardware", + ], } 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, -}; diff --git a/boot_control/include/libboot_control/libboot_control.h b/boot_control/include/libboot_control/libboot_control.h new file mode 100644 index 000000000..6582d0244 --- /dev/null +++ b/boot_control/include/libboot_control/libboot_control.h @@ -0,0 +1,58 @@ +// +// Copyright (C) 2019 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. +// + +#pragma once + +#include + +namespace android { +namespace bootable { + +// Helper library to implement the IBootControl HAL using the misc partition. +class BootControl { + public: + bool Init(); + unsigned int GetNumberSlots(); + unsigned int GetCurrentSlot(); + bool MarkBootSuccessful(); + bool SetActiveBootSlot(unsigned int slot); + bool SetSlotAsUnbootable(unsigned int slot); + bool SetSlotBootable(unsigned int slot); + bool IsSlotBootable(unsigned int slot); + const char* GetSuffix(unsigned int slot); + bool IsSlotMarkedSuccessful(unsigned int slot); + + const std::string& misc_device() const { + return misc_device_; + } + + private: + // Whether this object was initialized with data from the bootloader message + // that doesn't change until next reboot. + bool initialized_ = false; + + // The path to the misc_device as reported in the fstab. + std::string misc_device_; + + // The number of slots present on the device. + unsigned int num_slots_ = 0; + + // The slot where we are running from. + unsigned int current_slot_ = 0; +}; + +} // namespace bootable +} // namespace android diff --git a/boot_control/legacy_boot_control.cpp b/boot_control/legacy_boot_control.cpp new file mode 100644 index 000000000..73d3a5841 --- /dev/null +++ b/boot_control/legacy_boot_control.cpp @@ -0,0 +1,115 @@ +/* + * 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 + +using android::bootable::BootControl; + +struct boot_control_private_t { + // The base struct needs to be first in the list. + boot_control_module_t base; + + BootControl impl; +}; + +namespace { + +void BootControl_init(boot_control_module_t* module) { + auto& impl = reinterpret_cast(module)->impl; + impl.Init(); +} + +unsigned int BootControl_getNumberSlots(boot_control_module_t* module) { + auto& impl = reinterpret_cast(module)->impl; + return impl.GetNumberSlots(); +} + +unsigned int BootControl_getCurrentSlot(boot_control_module_t* module) { + auto& impl = reinterpret_cast(module)->impl; + return impl.GetCurrentSlot(); +} + +int BootControl_markBootSuccessful(boot_control_module_t* module) { + auto& impl = reinterpret_cast(module)->impl; + return impl.MarkBootSuccessful() ? 0 : -1; +} + +int BootControl_setActiveBootSlot(boot_control_module_t* module, unsigned int slot) { + auto& impl = reinterpret_cast(module)->impl; + return impl.SetActiveBootSlot(slot) ? 0 : -1; +} + +int BootControl_setSlotAsUnbootable(struct boot_control_module* module, unsigned int slot) { + auto& impl = reinterpret_cast(module)->impl; + return impl.SetSlotAsUnbootable(slot) ? 0 : -1; +} + +int BootControl_isSlotBootable(struct boot_control_module* module, unsigned int slot) { + auto& impl = reinterpret_cast(module)->impl; + return impl.IsSlotBootable(slot) ? 0 : -1; +} + +int BootControl_isSlotMarkedSuccessful(struct boot_control_module* module, unsigned int slot) { + auto& impl = reinterpret_cast(module)->impl; + return impl.IsSlotMarkedSuccessful(slot) ? 0 : -1; +} + +const char* BootControl_getSuffix(boot_control_module_t* module, unsigned int slot) { + auto& impl = reinterpret_cast(module)->impl; + return impl.GetSuffix(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, + }, +}; diff --git a/boot_control/libboot_control.cpp b/boot_control/libboot_control.cpp new file mode 100644 index 000000000..8b44d5d1c --- /dev/null +++ b/boot_control/libboot_control.cpp @@ -0,0 +1,328 @@ +/* + * 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 + +namespace android { +namespace bootable { + +// 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 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", ""); + 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. + misc_device_ = strdup(device.c_str()); + 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); + } + + 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; +} + +const char* BootControl::GetSuffix(unsigned int slot) { + if (slot >= kMaxNumSlots || slot >= num_slots_) { + return nullptr; + } + return kSlotSuffixes[slot]; +} + +} // namespace bootable +} // namespace android -- cgit v1.2.3