1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef _BOOTLOADER_MESSAGE_H 18 #define _BOOTLOADER_MESSAGE_H 19 20 #include <assert.h> 21 #include <stddef.h> 22 #include <stdint.h> 23 24 // Spaces used by misc partition are as below: 25 // 0 - 2K For bootloader_message 26 // 2K - 16K Used by Vendor's bootloader (the 2K - 4K range may be optionally used 27 // as bootloader_message_ab struct) 28 // 16K - 64K Used by uncrypt and recovery to store wipe_package for A/B devices 29 // Note that these offsets are admitted by bootloader,recovery and uncrypt, so they 30 // are not configurable without changing all of them. 31 static const size_t BOOTLOADER_MESSAGE_OFFSET_IN_MISC = 0; 32 static const size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024; 33 34 /* Bootloader Message (2-KiB) 35 * 36 * This structure describes the content of a block in flash 37 * that is used for recovery and the bootloader to talk to 38 * each other. 39 * 40 * The command field is updated by linux when it wants to 41 * reboot into recovery or to update radio or bootloader firmware. 42 * It is also updated by the bootloader when firmware update 43 * is complete (to boot into recovery for any final cleanup) 44 * 45 * The status field was used by the bootloader after the completion 46 * of an "update-radio" or "update-hboot" command, which has been 47 * deprecated since Froyo. 48 * 49 * The recovery field is only written by linux and used 50 * for the system to send a message to recovery or the 51 * other way around. 52 * 53 * The stage field is written by packages which restart themselves 54 * multiple times, so that the UI can reflect which invocation of the 55 * package it is. If the value is of the format "#/#" (eg, "1/3"), 56 * the UI will add a simple indicator of that status. 57 * 58 * We used to have slot_suffix field for A/B boot control metadata in 59 * this struct, which gets unintentionally cleared by recovery or 60 * uncrypt. Move it into struct bootloader_message_ab to avoid the 61 * issue. 62 */ 63 struct bootloader_message { 64 char command[32]; 65 char status[32]; 66 char recovery[768]; 67 68 // The 'recovery' field used to be 1024 bytes. It has only ever 69 // been used to store the recovery command line, so 768 bytes 70 // should be plenty. We carve off the last 256 bytes to store the 71 // stage string (for multistage packages) and possible future 72 // expansion. 73 char stage[32]; 74 75 // The 'reserved' field used to be 224 bytes when it was initially 76 // carved off from the 1024-byte recovery field. Bump it up to 77 // 1184-byte so that the entire bootloader_message struct rounds up 78 // to 2048-byte. 79 char reserved[1184]; 80 }; 81 82 /** 83 * We must be cautious when changing the bootloader_message struct size, 84 * because A/B-specific fields may end up with different offsets. 85 */ 86 #if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus) 87 static_assert(sizeof(struct bootloader_message) == 2048, 88 "struct bootloader_message size changes, which may break A/B devices"); 89 #endif 90 91 /** 92 * The A/B-specific bootloader message structure (4-KiB). 93 * 94 * We separate A/B boot control metadata from the regular bootloader 95 * message struct and keep it here. Everything that's A/B-specific 96 * stays after struct bootloader_message, which should be managed by 97 * the A/B-bootloader or boot control HAL. 98 * 99 * The slot_suffix field is used for A/B implementations where the 100 * bootloader does not set the androidboot.ro.boot.slot_suffix kernel 101 * commandline parameter. This is used by fs_mgr to mount /system and 102 * other partitions with the slotselect flag set in fstab. A/B 103 * implementations are free to use all 32 bytes and may store private 104 * data past the first NUL-byte in this field. It is encouraged, but 105 * not mandatory, to use 'struct bootloader_control' described below. 106 * 107 * The update_channel field is used to store the Omaha update channel 108 * if update_engine is compiled with Omaha support. 109 */ 110 struct bootloader_message_ab { 111 struct bootloader_message message; 112 char slot_suffix[32]; 113 char update_channel[128]; 114 115 // Round up the entire struct to 4096-byte. 116 char reserved[1888]; 117 }; 118 119 /** 120 * Be cautious about the struct size change, in case we put anything post 121 * bootloader_message_ab struct (b/29159185). 122 */ 123 #if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus) 124 static_assert(sizeof(struct bootloader_message_ab) == 4096, 125 "struct bootloader_message_ab size changes"); 126 #endif 127 128 #define BOOT_CTRL_MAGIC 0x42414342 /* Bootloader Control AB */ 129 #define BOOT_CTRL_VERSION 1 130 131 struct slot_metadata { 132 // Slot priority with 15 meaning highest priority, 1 lowest 133 // priority and 0 the slot is unbootable. 134 uint8_t priority : 4; 135 // Number of times left attempting to boot this slot. 136 uint8_t tries_remaining : 3; 137 // 1 if this slot has booted successfully, 0 otherwise. 138 uint8_t successful_boot : 1; 139 // 1 if this slot is corrupted from a dm-verity corruption, 0 140 // otherwise. 141 uint8_t verity_corrupted : 1; 142 // Reserved for further use. 143 uint8_t reserved : 7; 144 } __attribute__((packed)); 145 146 /* Bootloader Control AB 147 * 148 * This struct can be used to manage A/B metadata. It is designed to 149 * be put in the 'slot_suffix' field of the 'bootloader_message' 150 * structure described above. It is encouraged to use the 151 * 'bootloader_control' structure to store the A/B metadata, but not 152 * mandatory. 153 */ 154 struct bootloader_control { 155 // NUL terminated active slot suffix. 156 char slot_suffix[4]; 157 // Bootloader Control AB magic number (see BOOT_CTRL_MAGIC). 158 uint32_t magic; 159 // Version of struct being used (see BOOT_CTRL_VERSION). 160 uint8_t version; 161 // Number of slots being managed. 162 uint8_t nb_slot : 3; 163 // Number of times left attempting to boot recovery. 164 uint8_t recovery_tries_remaining : 3; 165 // Ensure 4-bytes alignment for slot_info field. 166 uint8_t reserved0[2]; 167 // Per-slot information. Up to 4 slots. 168 struct slot_metadata slot_info[4]; 169 // Reserved for further use. 170 uint8_t reserved1[8]; 171 // CRC32 of all 28 bytes preceding this field (little endian 172 // format). 173 uint32_t crc32_le; 174 } __attribute__((packed)); 175 176 #if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus) 177 static_assert(sizeof(struct bootloader_control) == 178 sizeof(((struct bootloader_message_ab *)0)->slot_suffix), 179 "struct bootloader_control has wrong size"); 180 #endif 181 182 #ifdef __cplusplus 183 184 #include <string> 185 #include <vector> 186 187 // Return the block device name for the bootloader message partition and waits 188 // for the device for up to 10 seconds. In case of error returns the empty 189 // string. 190 std::string get_bootloader_message_blk_device(std::string* err); 191 192 // Read bootloader message into boot. Error message will be set in err. 193 bool read_bootloader_message(bootloader_message* boot, std::string* err); 194 195 // Read bootloader message from the specified misc device into boot. 196 bool read_bootloader_message_from(bootloader_message* boot, const std::string& misc_blk_device, 197 std::string* err); 198 199 // Read bootloader control block from the specified misc device into boot_ctrl. 200 bool read_bootloader_control_from(bootloader_control* boot_ctrl, const std::string& misc_blk_device, 201 std::string* err); 202 203 // Write bootloader message to BCB. 204 bool write_bootloader_message(const bootloader_message& boot, std::string* err); 205 206 // Write bootloader message to the specified BCB device. 207 bool write_bootloader_message_to(const bootloader_message& boot, 208 const std::string& misc_blk_device, std::string* err); 209 210 // Write bootloader message (boots into recovery with the options) to BCB. Will 211 // set the command and recovery fields, and reset the rest. 212 bool write_bootloader_message(const std::vector<std::string>& options, std::string* err); 213 214 // Write bootloader control block to the specified BCB device. 215 bool write_bootloader_control_to(const bootloader_control* boot_ctrl, const std::string& misc_blk_device, 216 std::string* err); 217 218 // Update bootloader message (boots into recovery with the options) to BCB. Will 219 // only update the command and recovery fields. 220 bool update_bootloader_message(const std::vector<std::string>& options, std::string* err); 221 222 // Update bootloader message (boots into recovery with the |options|) in |boot|. Will only update 223 // the command and recovery fields. 224 bool update_bootloader_message_in_struct(bootloader_message* boot, 225 const std::vector<std::string>& options); 226 227 // Clear BCB. 228 bool clear_bootloader_message(std::string* err); 229 230 // Writes the reboot-bootloader reboot reason to the bootloader_message. 231 bool write_reboot_bootloader(std::string* err); 232 233 // Read the wipe package from BCB (from offset WIPE_PACKAGE_OFFSET_IN_MISC). 234 bool read_wipe_package(std::string* package_data, size_t size, std::string* err); 235 236 // Write the wipe package into BCB (to offset WIPE_PACKAGE_OFFSET_IN_MISC). 237 bool write_wipe_package(const std::string& package_data, std::string* err); 238 239 #else 240 241 #include <stdbool.h> 242 243 // C Interface. 244 bool write_bootloader_message(const char* options); 245 bool write_reboot_bootloader(void); 246 247 #endif // ifdef __cplusplus 248 249 #endif // _BOOTLOADER_MESSAGE_H 250