diff options
Diffstat (limited to 'bootloader_message')
| -rw-r--r-- | bootloader_message/Android.mk | 24 | ||||
| -rw-r--r-- | bootloader_message/bootloader_message.cpp | 179 | ||||
| -rw-r--r-- | bootloader_message/include/bootloader_message/bootloader_message.h | 198 |
3 files changed, 401 insertions, 0 deletions
diff --git a/bootloader_message/Android.mk b/bootloader_message/Android.mk new file mode 100644 index 000000000..815ac67d7 --- /dev/null +++ b/bootloader_message/Android.mk @@ -0,0 +1,24 @@ +# Copyright (C) 2016 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. + +LOCAL_PATH := $(call my-dir) + +include $(CLEAR_VARS) +LOCAL_CLANG := true +LOCAL_SRC_FILES := bootloader_message.cpp +LOCAL_MODULE := libbootloader_message +LOCAL_STATIC_LIBRARIES := libbase libfs_mgr +LOCAL_C_INCLUDES := $(LOCAL_PATH)/include +LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include +include $(BUILD_STATIC_LIBRARY) diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp new file mode 100644 index 000000000..62d8c6785 --- /dev/null +++ b/bootloader_message/bootloader_message.cpp @@ -0,0 +1,179 @@ +/* + * Copyright (C) 2016 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include <bootloader_message/bootloader_message.h> + +#include <errno.h> +#include <fcntl.h> +#include <string.h> + +#include <string> +#include <vector> + +#include <android-base/file.h> +#include <android-base/properties.h> +#include <android-base/stringprintf.h> +#include <android-base/unique_fd.h> +#include <fs_mgr.h> + +static struct fstab* read_fstab(std::string* err) { + std::string ro_hardware = android::base::GetProperty("ro.hardware", ""); + if (ro_hardware.empty()) { + *err = "failed to get ro.hardware"; + return nullptr; + } + // The fstab path is always "/fstab.${ro.hardware}". + std::string fstab_path = "/fstab." + ro_hardware; + struct fstab* fstab = fs_mgr_read_fstab(fstab_path.c_str()); + if (fstab == nullptr) { + *err = "failed to read " + fstab_path; + } + return fstab; +} + +static std::string get_misc_blk_device(std::string* err) { + struct fstab* fstab = read_fstab(err); + if (fstab == nullptr) { + return ""; + } + fstab_rec* record = fs_mgr_get_entry_for_mount_point(fstab, "/misc"); + if (record == nullptr) { + *err = "failed to find /misc partition"; + return ""; + } + return record->blk_device; +} + +// In recovery mode, recovery can get started and try to access the misc +// device before the kernel has actually created it. +static bool wait_for_device(const std::string& blk_device, std::string* err) { + int tries = 0; + int ret; + err->clear(); + do { + ++tries; + struct stat buf; + ret = stat(blk_device.c_str(), &buf); + if (ret == -1) { + *err += android::base::StringPrintf("failed to stat %s try %d: %s\n", + blk_device.c_str(), tries, strerror(errno)); + sleep(1); + } + } while (ret && tries < 10); + + if (ret) { + *err += android::base::StringPrintf("failed to stat %s\n", blk_device.c_str()); + } + return ret == 0; +} + +static bool read_misc_partition(void* p, size_t size, size_t offset, std::string* err) { + std::string misc_blk_device = get_misc_blk_device(err); + if (misc_blk_device.empty()) { + return false; + } + if (!wait_for_device(misc_blk_device, err)) { + return false; + } + android::base::unique_fd fd(open(misc_blk_device.c_str(), O_WRONLY | O_SYNC)); + if (fd.get() == -1) { + *err = android::base::StringPrintf("failed to open %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + if (lseek(fd.get(), static_cast<off_t>(offset), SEEK_SET) != static_cast<off_t>(offset)) { + *err = android::base::StringPrintf("failed to lseek %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + if (!android::base::ReadFully(fd.get(), p, size)) { + *err = android::base::StringPrintf("failed to read %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + return true; +} + +static bool write_misc_partition(const void* p, size_t size, size_t offset, std::string* err) { + std::string misc_blk_device = get_misc_blk_device(err); + if (misc_blk_device.empty()) { + return false; + } + android::base::unique_fd fd(open(misc_blk_device.c_str(), O_WRONLY | O_SYNC)); + if (fd.get() == -1) { + *err = android::base::StringPrintf("failed to open %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + if (lseek(fd.get(), static_cast<off_t>(offset), SEEK_SET) != static_cast<off_t>(offset)) { + *err = android::base::StringPrintf("failed to lseek %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + if (!android::base::WriteFully(fd.get(), p, size)) { + *err = android::base::StringPrintf("failed to write %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + // TODO: O_SYNC and fsync duplicates each other? + if (fsync(fd.get()) == -1) { + *err = android::base::StringPrintf("failed to fsync %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + return true; +} + +bool read_bootloader_message(bootloader_message* boot, std::string* err) { + return read_misc_partition(boot, sizeof(*boot), BOOTLOADER_MESSAGE_OFFSET_IN_MISC, err); +} + +bool write_bootloader_message(const bootloader_message& boot, std::string* err) { + return write_misc_partition(&boot, sizeof(boot), BOOTLOADER_MESSAGE_OFFSET_IN_MISC, err); +} + +bool clear_bootloader_message(std::string* err) { + bootloader_message boot = {}; + return write_bootloader_message(boot, err); +} + +bool write_bootloader_message(const std::vector<std::string>& options, std::string* err) { + bootloader_message boot = {}; + strlcpy(boot.command, "boot-recovery", sizeof(boot.command)); + strlcpy(boot.recovery, "recovery\n", sizeof(boot.recovery)); + for (const auto& s : options) { + strlcat(boot.recovery, s.c_str(), sizeof(boot.recovery)); + if (s.back() != '\n') { + strlcat(boot.recovery, "\n", sizeof(boot.recovery)); + } + } + return write_bootloader_message(boot, err); +} + +bool read_wipe_package(std::string* package_data, size_t size, std::string* err) { + package_data->resize(size); + return read_misc_partition(&(*package_data)[0], size, WIPE_PACKAGE_OFFSET_IN_MISC, err); +} + +bool write_wipe_package(const std::string& package_data, std::string* err) { + return write_misc_partition(package_data.data(), package_data.size(), + WIPE_PACKAGE_OFFSET_IN_MISC, err); +} + +extern "C" bool write_bootloader_message(const char* options) { + std::string err; + return write_bootloader_message({options}, &err); +} diff --git a/bootloader_message/include/bootloader_message/bootloader_message.h b/bootloader_message/include/bootloader_message/bootloader_message.h new file mode 100644 index 000000000..07ecf8576 --- /dev/null +++ b/bootloader_message/include/bootloader_message/bootloader_message.h @@ -0,0 +1,198 @@ +/* + * Copyright (C) 2008 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. + */ + +#ifndef _BOOTLOADER_MESSAGE_H +#define _BOOTLOADER_MESSAGE_H + +#include <assert.h> +#include <stddef.h> +#include <stdint.h> + +// Spaces used by misc partition are as below: +// 0 - 2K Bootloader Message +// 2K - 16K Used by Vendor's bootloader (the 2K - 4K range may be optionally used +// as bootloader_message_ab struct) +// 16K - 64K Used by uncrypt and recovery to store wipe_package for A/B devices +// Note that these offsets are admitted by bootloader,recovery and uncrypt, so they +// are not configurable without changing all of them. +static const size_t BOOTLOADER_MESSAGE_OFFSET_IN_MISC = 0; +static const size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024; + +/* Bootloader Message (2-KiB) + * + * This structure describes the content of a block in flash + * that is used for recovery and the bootloader to talk to + * each other. + * + * The command field is updated by linux when it wants to + * reboot into recovery or to update radio or bootloader firmware. + * It is also updated by the bootloader when firmware update + * is complete (to boot into recovery for any final cleanup) + * + * The status field is written by the bootloader after the + * completion of an "update-radio" or "update-hboot" command. + * + * The recovery field is only written by linux and used + * for the system to send a message to recovery or the + * other way around. + * + * The stage field is written by packages which restart themselves + * multiple times, so that the UI can reflect which invocation of the + * package it is. If the value is of the format "#/#" (eg, "1/3"), + * the UI will add a simple indicator of that status. + * + * We used to have slot_suffix field for A/B boot control metadata in + * this struct, which gets unintentionally cleared by recovery or + * uncrypt. Move it into struct bootloader_message_ab to avoid the + * issue. + */ +struct bootloader_message { + char command[32]; + char status[32]; + char recovery[768]; + + // The 'recovery' field used to be 1024 bytes. It has only ever + // been used to store the recovery command line, so 768 bytes + // should be plenty. We carve off the last 256 bytes to store the + // stage string (for multistage packages) and possible future + // expansion. + char stage[32]; + + // The 'reserved' field used to be 224 bytes when it was initially + // carved off from the 1024-byte recovery field. Bump it up to + // 1184-byte so that the entire bootloader_message struct rounds up + // to 2048-byte. + char reserved[1184]; +}; + +/** + * We must be cautious when changing the bootloader_message struct size, + * because A/B-specific fields may end up with different offsets. + */ +#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus) +static_assert(sizeof(struct bootloader_message) == 2048, + "struct bootloader_message size changes, which may break A/B devices"); +#endif + +/** + * The A/B-specific bootloader message structure (4-KiB). + * + * We separate A/B boot control metadata from the regular bootloader + * message struct and keep it here. Everything that's A/B-specific + * stays after struct bootloader_message, which should be managed by + * the A/B-bootloader or boot control HAL. + * + * The slot_suffix field is used for A/B implementations where the + * bootloader does not set the androidboot.ro.boot.slot_suffix kernel + * commandline parameter. This is used by fs_mgr to mount /system and + * other partitions with the slotselect flag set in fstab. A/B + * implementations are free to use all 32 bytes and may store private + * data past the first NUL-byte in this field. It is encouraged, but + * not mandatory, to use 'struct bootloader_control' described below. + */ +struct bootloader_message_ab { + struct bootloader_message message; + char slot_suffix[32]; + + // Round up the entire struct to 4096-byte. + char reserved[2016]; +}; + +/** + * Be cautious about the struct size change, in case we put anything post + * bootloader_message_ab struct (b/29159185). + */ +#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus) +static_assert(sizeof(struct bootloader_message_ab) == 4096, + "struct bootloader_message_ab size changes"); +#endif + +#define BOOT_CTRL_MAGIC 0x42414342 /* Bootloader Control AB */ +#define BOOT_CTRL_VERSION 1 + +struct slot_metadata { + // Slot priority with 15 meaning highest priority, 1 lowest + // priority and 0 the slot is unbootable. + uint8_t priority : 4; + // Number of times left attempting to boot this slot. + uint8_t tries_remaining : 3; + // 1 if this slot has booted successfully, 0 otherwise. + uint8_t successful_boot : 1; + // 1 if this slot is corrupted from a dm-verity corruption, 0 + // otherwise. + uint8_t verity_corrupted : 1; + // Reserved for further use. + uint8_t reserved : 7; +} __attribute__((packed)); + +/* Bootloader Control AB + * + * This struct can be used to manage A/B metadata. It is designed to + * be put in the 'slot_suffix' field of the 'bootloader_message' + * structure described above. It is encouraged to use the + * 'bootloader_control' structure to store the A/B metadata, but not + * mandatory. + */ +struct bootloader_control { + // NUL terminated active slot suffix. + char slot_suffix[4]; + // Bootloader Control AB magic number (see BOOT_CTRL_MAGIC). + uint32_t magic; + // Version of struct being used (see BOOT_CTRL_VERSION). + uint8_t version; + // Number of slots being managed. + uint8_t nb_slot : 3; + // Number of times left attempting to boot recovery. + uint8_t recovery_tries_remaining : 3; + // Ensure 4-bytes alignment for slot_info field. + uint8_t reserved0[2]; + // Per-slot information. Up to 4 slots. + struct slot_metadata slot_info[4]; + // Reserved for further use. + uint8_t reserved1[8]; + // CRC32 of all 28 bytes preceding this field (little endian + // format). + uint32_t crc32_le; +} __attribute__((packed)); + +#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus) +static_assert(sizeof(struct bootloader_control) == + sizeof(((struct bootloader_message_ab *)0)->slot_suffix), + "struct bootloader_control has wrong size"); +#endif +#ifdef __cplusplus + +#include <string> +#include <vector> + +bool read_bootloader_message(bootloader_message* boot, std::string* err); +bool write_bootloader_message(const bootloader_message& boot, std::string* err); +bool write_bootloader_message(const std::vector<std::string>& options, std::string* err); +bool clear_bootloader_message(std::string* err); + +bool read_wipe_package(std::string* package_data, size_t size, std::string* err); +bool write_wipe_package(const std::string& package_data, std::string* err); + +#else + +#include <stdbool.h> + +// C Interface. +bool write_bootloader_message(const char* options); + +#endif // ifdef __cplusplus + +#endif // _BOOTLOADER_MESSAGE_H |