Magisk/native/jni/magiskboot/bootimg.h

#include <stdint.h>
#include "format.h"

#ifndef _BOOT_IMAGE_H_
#define _BOOT_IMAGE_H_

struct boot_img_hdr_base {
	char magic[8];

	uint32_t kernel_size;  /* size in bytes */
	uint32_t kernel_addr;  /* physical load addr */

	uint32_t ramdisk_size; /* size in bytes */
	uint32_t ramdisk_addr; /* physical load addr */

	uint32_t second_size;  /* size in bytes */
	uint32_t second_addr;  /* physical load addr */
} __attribute__((packed));

struct boot_img_hdr_v0 : public boot_img_hdr_base {
	uint32_t tags_addr;    /* physical addr for kernel tags */
	uint32_t page_size;    /* flash page size we assume */

	/* In header v1, this field is used for header version
	 * However, on some devices like Samsung, this field is used to store DTB
	 * We will treat this field differently based on its value */
	union {
		uint32_t header_version;  /* the version of the header */
		uint32_t extra_size;      /* extra blob size in bytes */
	};

	/* operating system version and security patch level; for
	 * version "A.B.C" and patch level "Y-M-D":
	 * ver = A << 14 | B << 7 | C         (7 bits for each of A, B, C)
	 * lvl = ((Y - 2000) & 127) << 4 | M  (7 bits for Y, 4 bits for M)
	 * os_version = ver << 11 | lvl */
	uint32_t os_version;

	char name[16];         /* asciiz product name */
	char cmdline[512];
	char id[32];           /* timestamp / checksum / sha1 / etc */

	/* Supplemental command line data; kept here to maintain
	 * binary compatibility with older versions of mkbootimg */
	char extra_cmdline[1024];
} __attribute__((packed));

struct boot_img_hdr_v1 : public boot_img_hdr_v0 {
	uint32_t recovery_dtbo_size;   /* size in bytes for recovery DTBO image */
	uint64_t recovery_dtbo_offset; /* offset to recovery dtbo in boot image */
	uint32_t header_size;
} __attribute__((packed));

// Default to hdr v1
typedef boot_img_hdr_v1 boot_img_hdr;

// Special Samsung header
struct boot_img_hdr_pxa : public boot_img_hdr_base {
	uint32_t extra_size;   /* extra blob size in bytes */
	uint32_t unknown;      /* unknown value */
	uint32_t tags_addr;    /* physical addr for kernel tags */
	uint32_t page_size;    /* flash page size we assume */

	char name[24];         /* asciiz product name */
	char cmdline[512];
	char id[32];           /* timestamp / checksum / sha1 / etc */

	/* Supplemental command line data; kept here to maintain
	 * binary compatibility with older versions of mkbootimg */
	char extra_cmdline[1024];
} __attribute__((packed));

/*
** +-----------------+
** | boot header     | 1 page
** +-----------------+
** | kernel          | n pages
** +-----------------+
** | ramdisk         | m pages
** +-----------------+
** | second stage    | o pages
** +-----------------+
** | extra blob      | p pages
** +-----------------+
** | recovery dtbo   | q pages
** +-----------------+
**
** n = (kernel_size + page_size - 1) / page_size
** m = (ramdisk_size + page_size - 1) / page_size
** o = (second_size + page_size - 1) / page_size
** p = (extra_size + page_size - 1) / page_size
** q = (recovery_dtbo_size + page_size - 1) / page_size
**
** 0. all entities are page_size aligned in flash
** 1. kernel and ramdisk are required (size != 0)
** 2. second is optional (second_size == 0 -> no second)
** 3. load each element (kernel, ramdisk, second) at
**    the specified physical address (kernel_addr, etc)
** 4. prepare tags at tag_addr.  kernel_args[] is
**    appended to the kernel commandline in the tags.
** 5. r0 = 0, r1 = MACHINE_TYPE, r2 = tags_addr
** 6. if second_size != 0: jump to second_addr
**    else: jump to kernel_addr
*/

struct mtk_hdr {
	uint32_t magic;      /* MTK magic */
	uint32_t size;       /* Size of the content */
	char name[32];       /* The type of the header */
} __attribute__((packed));

struct dhtb_hdr {
	char magic[8];         /* DHTB magic */
	uint8_t checksum[40];  /* Payload SHA256, whole image + SEANDROIDENFORCE + 0xFFFFFFFF */
	uint32_t size;         /* Payload size, whole image + SEANDROIDENFORCE + 0xFFFFFFFF */
} __attribute__((packed));

struct blob_hdr {
	char secure_magic[20];  /* "-SIGNED-BY-SIGNBLOB-" */
	uint32_t datalen;       /* 0x00000000 */
	uint32_t signature;     /* 0x00000000 */
	char magic[16];         /* "MSM-RADIO-UPDATE" */
	uint32_t hdr_version;   /* 0x00010000 */
	uint32_t hdr_size;      /* Size of header */
	uint32_t part_offset;   /* Same as size */
	uint32_t num_parts;     /* Number of partitions */
	uint32_t unknown[7];    /* All 0x00000000 */
	char name[4];           /* Name of partition */
	uint32_t offset;        /* offset in blob where this partition starts */
	uint32_t size;          /* Size of data */
	uint32_t version;       /* 0x00000001 */
} __attribute__((packed));

// Flags
#define MTK_KERNEL      0x0001
#define MTK_RAMDISK     0x0002
#define CHROMEOS_FLAG   0x0004
#define PXA_FLAG        0x0008
#define DHTB_FLAG       0x0010
#define SEANDROID_FLAG  0x0020
#define LG_BUMP_FLAG    0x0040
#define SHA256_FLAG     0x0080
#define BLOB_FLAG       0x0100
#define NOOKHD_FLAG     0x0200
#define ACCLAIM_FLAG    0x0400

struct boot_img {
	// Memory map of the whole image
	uint8_t *map_addr;
	size_t map_size;

	// Headers
	boot_img_hdr_base *hdr;  /* Android boot image header */
	mtk_hdr *k_hdr;          /* MTK kernel header */
	mtk_hdr *r_hdr;          /* MTK ramdisk header */
	blob_hdr *b_hdr;         /* Tegra blob header */

	// Flags to indicate the state of current boot image
	uint16_t flags;

	// The format of kernel and ramdisk
	format_t k_fmt;
	format_t r_fmt;

	// Pointer to dtb that is appended after kernel
	uint8_t *dtb;
	uint32_t dt_size;

	// Pointer to end of image
	uint8_t *tail;
	size_t tail_size;

	// Pointers to blocks defined in header
	uint8_t *kernel;
	uint8_t *ramdisk;
	uint8_t *second;
	uint8_t *extra;
	uint8_t *recov_dtbo;

	~boot_img();

	int parse_image(const char *);
	void find_dtb();
	void print_hdr();

	/* Access elements in header */

#define IS_PXA (flags & PXA_FLAG)
#define dyn_access(x) (IS_PXA ? \
static_cast<boot_img_hdr_pxa *>(hdr)->x : \
static_cast<boot_img_hdr_v1 *>(hdr)->x)

#define dyn_get(x, t) t x() const { return dyn_access(x); }
#define dyn_set(x, t) void x(t v) { dyn_access(x) = v; }
#define hdr_get(x, t) t x() const { return IS_PXA ? 0 : static_cast<boot_img_hdr *>(hdr)->x; }
#define hdr_set(x, t) void x(t v) { if (!IS_PXA) static_cast<boot_img_hdr *>(hdr)->x = v; }

	dyn_set(extra_size, uint32_t);
	dyn_get(page_size, uint32_t);
	dyn_get(name, char *);
	dyn_get(cmdline, char *);
	dyn_get(id, char *);
	dyn_get(extra_cmdline, char *);

	hdr_get(os_version, uint32_t);
	hdr_get(recovery_dtbo_size, uint32_t);
	hdr_set(recovery_dtbo_size, uint32_t);
	hdr_get(recovery_dtbo_offset, uint32_t);
	hdr_set(recovery_dtbo_offset, uint32_t);
	hdr_get(header_size, uint32_t);
	hdr_set(header_size, uint32_t);

	uint32_t header_version() {
		if (IS_PXA)
			return 0;
		uint32_t ver = static_cast<boot_img_hdr *>(hdr)->header_version;
		// There won't be v4 header any time soon...
		// If larger than 4, assume this field will be treated as extra_size
		return ver > 4 ? 0 : ver;
	}

	uint32_t extra_size() {
		// If header version > 0, we should treat this field as header_version
		return header_version() ? 0 : dyn_access(extra_size);
	}

	size_t hdr_size() {
		return IS_PXA ? sizeof(boot_img_hdr_pxa) : sizeof(boot_img_hdr);
	}
};

#endif