path: root/src/mkrkboot.c

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * mkrkboot - build the Android boot image booted by Rockchip's U-Boot
 * together with the Rockchip resource image carrying the device tree
 */
#include <errno.h>
#include <getopt.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "sha1.h"

#define BLOCK_SIZE		512
#define SHA1_LEN		20
#define MAX_ENTRIES		16

#define BOOT_MAGIC		"ANDROID!"
#define BOOT_NAME_LEN		16
#define BOOT_CMDLINE_LEN	512
#define BOOT_ID_LEN		32
#define BOOT_EXTRA_LEN		1024
#define BOOT_OFF_KERNEL_SIZE	8
#define BOOT_OFF_KERNEL_ADDR	12
#define BOOT_OFF_SECOND_SIZE	24
#define BOOT_OFF_SECOND_ADDR	28
#define BOOT_OFF_TAGS_ADDR	32
#define BOOT_OFF_PAGE_SIZE	36
#define BOOT_OFF_NAME		48
#define BOOT_OFF_CMDLINE	(BOOT_OFF_NAME + BOOT_NAME_LEN)
#define BOOT_OFF_ID		(BOOT_OFF_CMDLINE + BOOT_CMDLINE_LEN)
#define BOOT_HDR_SIZE		(BOOT_OFF_ID + BOOT_ID_LEN + BOOT_EXTRA_LEN)

#define RES_MAGIC		"RSCE"
#define RES_ENTRY_MAGIC		"ENTR"
#define RES_PATH_LEN		220
#define RES_HASH_LEN		32
#define RES_OFF_HDR_BLOCKS	8
#define RES_OFF_TABLE_BLOCK	9
#define RES_OFF_ENTRY_BLOCKS	10
#define RES_OFF_COUNT		12
#define RES_OFF_PATH		4
#define RES_OFF_HASH		(RES_OFF_PATH + RES_PATH_LEN)
#define RES_OFF_HASH_SIZE	(RES_OFF_HASH + RES_HASH_LEN)
#define RES_OFF_OFFSET		(RES_OFF_HASH_SIZE + 4)
#define RES_OFF_SIZE		(RES_OFF_OFFSET + 4)

struct blob {
	uint8_t		*data;
	size_t		len;
};

struct res_entry {
	char		*path;
	struct blob	blob;
};

static void put_le32(uint8_t *buf, uint32_t val)
{
	buf[0] = val & 0xff;
	buf[1] = (val >> 8) & 0xff;
	buf[2] = (val >> 16) & 0xff;
	buf[3] = val >> 24;
}

static size_t round_up(size_t val, size_t align)
{
	return (val + align - 1) / align * align;
}

static int blob_read(const char *path, struct blob *blob)
{
	FILE *fp;
	long len;

	fp = fopen(path, "rb");
	if (!fp) {
		fprintf(stderr, "%s: %s\n", path, strerror(errno));
		return -1;
	}
	if (fseek(fp, 0, SEEK_END) || (len = ftell(fp)) < 0 ||
	    fseek(fp, 0, SEEK_SET)) {
		fprintf(stderr, "%s: cannot determine size\n", path);
		fclose(fp);
		return -1;
	}
	blob->len = len;
	blob->data = malloc(len ? len : 1);
	if (!blob->data || fread(blob->data, 1, len, fp) != (size_t)len) {
		fprintf(stderr, "%s: read failed\n", path);
		fclose(fp);
		return -1;
	}
	fclose(fp);
	return 0;
}

static int blob_write(const char *path, const struct blob *blob)
{
	FILE *fp;

	fp = fopen(path, "wb");
	if (!fp) {
		fprintf(stderr, "%s: %s\n", path, strerror(errno));
		return -1;
	}
	if (fwrite(blob->data, 1, blob->len, fp) != blob->len ||
	    fclose(fp)) {
		fprintf(stderr, "%s: write failed\n", path);
		return -1;
	}
	return 0;
}

static int res_build(struct res_entry *entries, int count,
		     struct blob *out)
{
	size_t table = BLOCK_SIZE + (size_t)count * BLOCK_SIZE;
	size_t offset;
	size_t total;
	uint8_t *ent;
	int i;

	total = table;
	for (i = 0; i < count; i++)
		total += round_up(entries[i].blob.len, BLOCK_SIZE);

	out->data = calloc(1, total);
	if (!out->data)
		return -1;
	out->len = total;

	memcpy(out->data, RES_MAGIC, 4);
	out->data[RES_OFF_HDR_BLOCKS] = 1;
	out->data[RES_OFF_TABLE_BLOCK] = 1;
	out->data[RES_OFF_ENTRY_BLOCKS] = 1;
	put_le32(out->data + RES_OFF_COUNT, count);

	offset = count + 1;
	for (i = 0; i < count; i++) {
		ent = out->data + BLOCK_SIZE + (size_t)i * BLOCK_SIZE;
		memcpy(ent, RES_ENTRY_MAGIC, 4);
		strncpy((char *)ent + RES_OFF_PATH, entries[i].path,
			RES_PATH_LEN - 1);
		sha1_csum(entries[i].blob.data, entries[i].blob.len,
			  ent + RES_OFF_HASH);
		put_le32(ent + RES_OFF_HASH_SIZE, SHA1_LEN);
		put_le32(ent + RES_OFF_OFFSET, offset);
		put_le32(ent + RES_OFF_SIZE, entries[i].blob.len);
		memcpy(out->data + offset * BLOCK_SIZE, entries[i].blob.data,
		       entries[i].blob.len);
		offset += round_up(entries[i].blob.len, BLOCK_SIZE) /
			  BLOCK_SIZE;
	}
	return 0;
}

static int boot_build(const struct blob *kernel, const struct blob *second,
		      uint32_t kernel_addr, uint32_t second_addr,
		      uint32_t tags_addr, const char *name,
		      const char *cmdline, size_t page, struct blob *out)
{
	size_t kernel_pad = round_up(kernel->len, page);
	size_t second_pad = round_up(second->len, page);
	size_t hdr_pad = round_up(BOOT_HDR_SIZE, page);
	uint8_t len_le[4];
	sha1_context sha;
	uint8_t *hdr;

	out->len = hdr_pad + kernel_pad + second_pad;
	out->data = calloc(1, out->len);
	if (!out->data)
		return -1;

	hdr = out->data;
	memcpy(hdr, BOOT_MAGIC, 8);
	put_le32(hdr + BOOT_OFF_KERNEL_SIZE, kernel->len);
	put_le32(hdr + BOOT_OFF_KERNEL_ADDR, kernel_addr);
	put_le32(hdr + BOOT_OFF_SECOND_SIZE, second->len);
	put_le32(hdr + BOOT_OFF_SECOND_ADDR, second_addr);
	put_le32(hdr + BOOT_OFF_TAGS_ADDR, tags_addr);
	put_le32(hdr + BOOT_OFF_PAGE_SIZE, page);
	strncpy((char *)hdr + BOOT_OFF_NAME, name, BOOT_NAME_LEN - 1);
	strncpy((char *)hdr + BOOT_OFF_CMDLINE, cmdline,
		BOOT_CMDLINE_LEN - 1);

	/* kernel, empty ramdisk and second stage, each followed by its size */
	sha1_starts(&sha);
	sha1_update(&sha, kernel->data, kernel->len);
	put_le32(len_le, kernel->len);
	sha1_update(&sha, len_le, 4);
	put_le32(len_le, 0);
	sha1_update(&sha, len_le, 4);
	sha1_update(&sha, second->data, second->len);
	put_le32(len_le, second->len);
	sha1_update(&sha, len_le, 4);
	sha1_finish(&sha, hdr + BOOT_OFF_ID);

	memcpy(out->data + hdr_pad, kernel->data, kernel->len);
	memcpy(out->data + hdr_pad + kernel_pad, second->data, second->len);
	return 0;
}

static void usage(const char *progname)
{
	fprintf(stderr,
		"Usage: %s -k <kernel> -d <dtb> -o <output> [options]\n"
		"\n"
		"Options:\n"
		"  -k <file>      kernel image\n"
		"  -d <file>      device tree, stored as rk-kernel.dtb\n"
		"  -e <name=file> additional resource image entry\n"
		"  -o <file>      output boot image\n"
		"  -a <addr>      kernel load address\n"
		"  -f <addr>      resource image load address\n"
		"  -t <addr>      kernel tags address\n"
		"  -c <string>    kernel command line\n"
		"  -n <string>    image name\n"
		"  -p <size>      page size (default 2048)\n"
		"  -h             show this help\n",
		progname);
}

int main(int argc, char *argv[])
{
	uint32_t kernel_addr = 0, second_addr = 0, tags_addr = 0;
	struct res_entry entries[MAX_ENTRIES];
	const char *cmdline = "", *name = "";
	struct blob resource, kernel, boot;
	const char *kernel_path = NULL;
	const char *out_path = NULL;
	const char *dtb_path = NULL;
	size_t page = 2048;
	int count = 1;
	char *sep;
	int opt;
	int i;

	while ((opt = getopt(argc, argv, "k:d:e:o:a:f:t:c:n:p:h")) != -1) {
		switch (opt) {
		case 'k':
			kernel_path = optarg;
			break;
		case 'd':
			dtb_path = optarg;
			break;
		case 'e':
			sep = strchr(optarg, '=');
			if (!sep || count >= MAX_ENTRIES) {
				usage(argv[0]);
				return EXIT_FAILURE;
			}
			*sep = '\0';
			entries[count].path = optarg;
			if (blob_read(sep + 1, &entries[count].blob))
				return EXIT_FAILURE;
			count++;
			break;
		case 'o':
			out_path = optarg;
			break;
		case 'a':
			kernel_addr = strtoul(optarg, NULL, 0);
			break;
		case 'f':
			second_addr = strtoul(optarg, NULL, 0);
			break;
		case 't':
			tags_addr = strtoul(optarg, NULL, 0);
			break;
		case 'c':
			cmdline = optarg;
			break;
		case 'n':
			name = optarg;
			break;
		case 'p':
			page = strtoul(optarg, NULL, 0);
			break;
		default:
			usage(argv[0]);
			return opt == 'h' ? EXIT_SUCCESS : EXIT_FAILURE;
		}
	}

	if (!kernel_path || !dtb_path || !out_path || !page) {
		usage(argv[0]);
		return EXIT_FAILURE;
	}

	entries[0].path = "rk-kernel.dtb";
	if (blob_read(dtb_path, &entries[0].blob) ||
	    blob_read(kernel_path, &kernel))
		return EXIT_FAILURE;

	for (i = 0; i < count; i++) {
		if (strlen(entries[i].path) >= RES_PATH_LEN) {
			fprintf(stderr, "%s: path too long\n", entries[i].path);
			return EXIT_FAILURE;
		}
	}

	if (res_build(entries, count, &resource) ||
	    boot_build(&kernel, &resource, kernel_addr, second_addr,
		       tags_addr, name, cmdline, page, &boot)) {
		fprintf(stderr, "out of memory\n");
		return EXIT_FAILURE;
	}

	return blob_write(out_path, &boot) ? EXIT_FAILURE : EXIT_SUCCESS;
}