Add bootloader_message_ab struct.

#ifndef _RECOVERY_BOOTLOADER_H

#define _RECOVERY_BOOTLOADER_H

/* Bootloader Message

#include <assert.h>

/* 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

 * package it is.  If the value is of the format "#/#" (eg, "1/3"),

 * the UI will add a simple indicator of that status.

 *

 * 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.

 * 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];

    // 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];

    char reserved[192];

    // 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

    uint32_t crc32_le;

} __attribute__((packed));

#if (__STDC_VERSION__ >= 201112L)

_Static_assert(sizeof(struct bootloader_control) ==

               sizeof(((struct bootloader_message *)0)->slot_suffix),

#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