include/android_bootloader_message.h

   1 /*
   2  * This is from the Android Project,
   3  * Repository: https://android.googlesource.com/platform/bootable/recovery
   4  * File: bootloader_message/include/bootloader_message/bootloader_message.h
   5  * Commit: See U-Boot commit description
   6  *
   7  * Copyright (C) 2008 The Android Open Source Project
   8  *
   9  * SPDX-License-Identifier: BSD-3-Clause
  10  */
  11
  12 #ifndef __ANDROID_BOOTLOADER_MESSAGE_H
  13 #define __ANDROID_BOOTLOADER_MESSAGE_H
  14
  15 #ifndef __UBOOT__
  16 #include <assert.h>
  17 #include <stddef.h>
  18 #include <stdint.h>
  19 #else
  20 /* compiler.h defines the types that otherwise are included from stdint.h and
  21  * stddef.h
  22  */
  23 #include <compiler.h>
  24 #endif
  25
  26 // Spaces used by misc partition are as below:
  27 // 0   - 2K     For bootloader_message
  28 // 2K  - 16K    Used by Vendor's bootloader (the 2K - 4K range may be optionally used
  29 //              as bootloader_message_ab struct)
  30 // 16K - 64K    Used by uncrypt and recovery to store wipe_package for A/B devices
  31 // Note that these offsets are admitted by bootloader,recovery and uncrypt, so they
  32 // are not configurable without changing all of them.
  33 static const size_t BOOTLOADER_MESSAGE_OFFSET_IN_MISC = 0;
  34 static const size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024;
  35
  36 /* Bootloader Message (2-KiB)
  37  *
  38  * This structure describes the content of a block in flash
  39  * that is used for recovery and the bootloader to talk to
  40  * each other.
  41  *
  42  * The command field is updated by linux when it wants to
  43  * reboot into recovery or to update radio or bootloader firmware.
  44  * It is also updated by the bootloader when firmware update
  45  * is complete (to boot into recovery for any final cleanup)
  46  *
  47  * The status field was used by the bootloader after the completion
  48  * of an "update-radio" or "update-hboot" command, which has been
  49  * deprecated since Froyo.
  50  *
  51  * The recovery field is only written by linux and used
  52  * for the system to send a message to recovery or the
  53  * other way around.
  54  *
  55  * The stage field is written by packages which restart themselves
  56  * multiple times, so that the UI can reflect which invocation of the
  57  * package it is.  If the value is of the format "#/#" (eg, "1/3"),
  58  * the UI will add a simple indicator of that status.
  59  *
  60  * We used to have slot_suffix field for A/B boot control metadata in
  61  * this struct, which gets unintentionally cleared by recovery or
  62  * uncrypt. Move it into struct bootloader_message_ab to avoid the
  63  * issue.
  64  */
  65 struct bootloader_message {
  66     char command[32];
  67     char status[32];
  68     char recovery[768];
  69
  70     // The 'recovery' field used to be 1024 bytes.  It has only ever
  71     // been used to store the recovery command line, so 768 bytes
  72     // should be plenty.  We carve off the last 256 bytes to store the
  73     // stage string (for multistage packages) and possible future
  74     // expansion.
  75     char stage[32];
  76
  77     // The 'reserved' field used to be 224 bytes when it was initially
  78     // carved off from the 1024-byte recovery field. Bump it up to
  79     // 1184-byte so that the entire bootloader_message struct rounds up
  80     // to 2048-byte.
  81     char reserved[1184];
  82 };
  83
  84 /**
  85  * We must be cautious when changing the bootloader_message struct size,
  86  * because A/B-specific fields may end up with different offsets.
  87  */
  88 #ifndef __UBOOT__
  89 #if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
  90 static_assert(sizeof(struct bootloader_message) == 2048,
  91               "struct bootloader_message size changes, which may break A/B devices");
  92 #endif
  93 #endif /* __UBOOT__ */
  94
  95 /**
  96  * The A/B-specific bootloader message structure (4-KiB).
  97  *
  98  * We separate A/B boot control metadata from the regular bootloader
  99  * message struct and keep it here. Everything that's A/B-specific
 100  * stays after struct bootloader_message, which should be managed by
 101  * the A/B-bootloader or boot control HAL.
 102  *
 103  * The slot_suffix field is used for A/B implementations where the
 104  * bootloader does not set the androidboot.ro.boot.slot_suffix kernel
 105  * commandline parameter. This is used by fs_mgr to mount /system and
 106  * other partitions with the slotselect flag set in fstab. A/B
 107  * implementations are free to use all 32 bytes and may store private
 108  * data past the first NUL-byte in this field. It is encouraged, but
 109  * not mandatory, to use 'struct bootloader_control' described below.
 110  *
 111  * The update_channel field is used to store the Omaha update channel
 112  * if update_engine is compiled with Omaha support.
 113  */
 114 struct bootloader_message_ab {
 115     struct bootloader_message message;
 116     char slot_suffix[32];
 117     char update_channel[128];
 118
 119     // Round up the entire struct to 4096-byte.
 120     char reserved[1888];
 121 };
 122
 123 /**
 124  * Be cautious about the struct size change, in case we put anything post
 125  * bootloader_message_ab struct (b/29159185).
 126  */
 127 #ifndef __UBOOT__
 128 #if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
 129 static_assert(sizeof(struct bootloader_message_ab) == 4096,
 130               "struct bootloader_message_ab size changes");
 131 #endif
 132 #endif /* __UBOOT__ */
 133
 134 #define BOOT_CTRL_MAGIC   0x42414342 /* Bootloader Control AB */
 135 #define BOOT_CTRL_VERSION 1
 136
 137 struct slot_metadata {
 138     // Slot priority with 15 meaning highest priority, 1 lowest
 139     // priority and 0 the slot is unbootable.
 140     uint8_t priority : 4;
 141     // Number of times left attempting to boot this slot.
 142     uint8_t tries_remaining : 3;
 143     // 1 if this slot has booted successfully, 0 otherwise.
 144     uint8_t successful_boot : 1;
 145     // 1 if this slot is corrupted from a dm-verity corruption, 0
 146     // otherwise.
 147     uint8_t verity_corrupted : 1;
 148     // Reserved for further use.
 149     uint8_t reserved : 7;
 150 } __attribute__((packed));
 151
 152 /* Bootloader Control AB
 153  *
 154  * This struct can be used to manage A/B metadata. It is designed to
 155  * be put in the 'slot_suffix' field of the 'bootloader_message'
 156  * structure described above. It is encouraged to use the
 157  * 'bootloader_control' structure to store the A/B metadata, but not
 158  * mandatory.
 159  */
 160 struct bootloader_control {
 161     // NUL terminated active slot suffix.
 162     char slot_suffix[4];
 163     // Bootloader Control AB magic number (see BOOT_CTRL_MAGIC).
 164     uint32_t magic;
 165     // Version of struct being used (see BOOT_CTRL_VERSION).
 166     uint8_t version;
 167     // Number of slots being managed.
 168     uint8_t nb_slot : 3;
 169     // Number of times left attempting to boot recovery.
 170     uint8_t recovery_tries_remaining : 3;
 171     // Ensure 4-bytes alignment for slot_info field.
 172     uint8_t reserved0[2];
 173     // Per-slot information.  Up to 4 slots.
 174     struct slot_metadata slot_info[4];
 175     // Reserved for further use.
 176     uint8_t reserved1[8];
 177     // CRC32 of all 28 bytes preceding this field (little endian
 178     // format).
 179     uint32_t crc32_le;
 180 } __attribute__((packed));
 181
 182 #ifndef __UBOOT__
 183 #if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
 184 static_assert(sizeof(struct bootloader_control) ==
 185               sizeof(((struct bootloader_message_ab *)0)->slot_suffix),
 186               "struct bootloader_control has wrong size");
 187 #endif
 188 #endif /* __UBOOT__ */
 189
 190 #ifndef __UBOOT__
 191 #ifdef __cplusplus
 192
 193 #include <string>
 194 #include <vector>
 195
 196 // Return the block device name for the bootloader message partition and waits
 197 // for the device for up to 10 seconds. In case of error returns the empty
 198 // string.
 199 std::string get_bootloader_message_blk_device(std::string* err);
 200
 201 // Read bootloader message into boot. Error message will be set in err.
 202 bool read_bootloader_message(bootloader_message* boot, std::string* err);
 203
 204 // Read bootloader message from the specified misc device into boot.
 205 bool read_bootloader_message_from(bootloader_message* boot, const std::string& misc_blk_device,
 206                                   std::string* err);
 207
 208 // Write bootloader message to BCB.
 209 bool write_bootloader_message(const bootloader_message& boot, std::string* err);
 210
 211 // Write bootloader message to the specified BCB device.
 212 bool write_bootloader_message_to(const bootloader_message& boot,
 213                                  const std::string& misc_blk_device, std::string* err);
 214
 215 // Write bootloader message (boots into recovery with the options) to BCB. Will
 216 // set the command and recovery fields, and reset the rest.
 217 bool write_bootloader_message(const std::vector<std::string>& options, std::string* err);
 218
 219 // Write bootloader message (boots into recovery with the options) to the specific BCB device. Will
 220 // set the command and recovery fields, and reset the rest.
 221 bool write_bootloader_message_to(const std::vector<std::string>& options,
 222                                  const std::string& misc_blk_device, std::string* err);
 223
 224 // Update bootloader message (boots into recovery with the options) to BCB. Will
 225 // only update the command and recovery fields.
 226 bool update_bootloader_message(const std::vector<std::string>& options, std::string* err);
 227
 228 // Update bootloader message (boots into recovery with the |options|) in |boot|. Will only update
 229 // the command and recovery fields.
 230 bool update_bootloader_message_in_struct(bootloader_message* boot,
 231                                          const std::vector<std::string>& options);
 232
 233 // Clear BCB.
 234 bool clear_bootloader_message(std::string* err);
 235
 236 // Writes the reboot-bootloader reboot reason to the bootloader_message.
 237 bool write_reboot_bootloader(std::string* err);
 238
 239 // Read the wipe package from BCB (from offset WIPE_PACKAGE_OFFSET_IN_MISC).
 240 bool read_wipe_package(std::string* package_data, size_t size, std::string* err);
 241
 242 // Write the wipe package into BCB (to offset WIPE_PACKAGE_OFFSET_IN_MISC).
 243 bool write_wipe_package(const std::string& package_data, std::string* err);
 244
 245 #else
 246
 247 #include <stdbool.h>
 248
 249 // C Interface.
 250 bool write_bootloader_message(const char* options);
 251 bool write_reboot_bootloader(void);
 252
 253 #endif  // ifdef __cplusplus
 254 #endif  /* __UBOOT__ */
 255
 256 #endif  /* __ANDROID_BOOTLOADER_MESSAGE_H */