/*
 * imagetag.c
 *
 * Copyright (C) 2005 Mike Baker
 * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
 * Copyrigth (C) 2010 Daniel Dickinson <openwrt@cshore.neomailbox.net>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <string.h>
#include <errno.h>

#include <sys/ioctl.h>
#include <mtd/mtd-user.h>
#include "mtd.h"
#include "crc32.h"
#include "bcm_tag.h"

ssize_t pread(int fd, void *buf, size_t count, off_t offset);
ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);

#define CRC_START 0xFFFFFFFF

static uint32_t strntoul(char *str, char **endptr, int base, size_t len) {
  char *newstr;
  uint32_t res = 0;

  newstr = calloc(len + 1, sizeof(char));
  if (newstr) {
	strncpy(newstr, str, len); 
	res = strtoul(newstr, endptr, base);
	free(newstr);
  }
  return res;
}

uint32_t compute_crc32(uint32_t crc, off_t start, size_t compute_len, int fd)
{
	uint8_t readbuf[1024];
	ssize_t res;
	off_t offset = start;

	/* Read a buffer's worth of bytes  */
	while (fd && (compute_len >= sizeof(readbuf))) {
		res = pread(fd, readbuf, sizeof(readbuf), offset);
		crc = crc32(crc, readbuf, res);
		compute_len = compute_len - res;
		offset += res;
	}

	/* Less than buffer-size bytes remains, read compute_len bytes */
	if (fd && (compute_len > 0)) {
	  res = pread(fd, readbuf, compute_len, offset);
	  crc = crc32(crc, readbuf, res);
	}

	return crc;
}

int
trx_fixup(int fd, const char *name)
{
	struct mtd_info_user mtdInfo;
	unsigned long len;
	void *ptr, *scan;
	int bfd;
	struct bcm_tag *tag;
	ssize_t res;
	uint32_t cfelen, imagelen, imagestart, rootfslen;
	uint32_t imagecrc, rootfscrc, headercrc;
	uint32_t offset = 0;
	cfelen = imagelen = imagestart = imagecrc = rootfscrc = headercrc = rootfslen = 0;


	if (ioctl(fd, MEMGETINFO, &mtdInfo) < 0) {
		fprintf(stderr, "Failed to get mtd info\n");
		goto err;
	}

	len = mtdInfo.size;
	if (mtdInfo.size <= 0) {
		fprintf(stderr, "Invalid MTD device size\n");
		goto err;
	}

	bfd = mtd_open(name, true);
	ptr = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, bfd, 0);
	if (!ptr || (ptr == (void *) -1)) {
		perror("mmap");
		goto err1;
	}

	tag = (struct bcm_tag *) (ptr);

	cfelen = strntoul(&tag->cfeLength[0], NULL, 10, IMAGE_LEN);
	if (cfelen) {
	  fprintf(stderr, "Non-zero CFE length.  This is currently unsupported.\n");
	  exit(1);
	}

	headercrc = compute_crc32(CRC_START, offset, offsetof(struct bcm_tag, headerCRC), fd);
	if (headercrc != *(uint32_t *)(&tag->headerCRC[0])) {
		fprintf(stderr, "Tag verify failed.  This may not be a valid image.\n");
		exit(1);
	}

	sprintf(&tag->flashRootLength[0], "%lu", 0);
	strncpy(&tag->totalLength[0], &tag->kernelLength[0], IMAGE_LEN);

	imagestart = sizeof(tag);
	memcpy(&tag->imageCRC[0], &tag->kernelCRC[0], CRC_LEN);
	memcpy(&tag->fskernelCRC[0], &tag->kernelCRC[0], CRC_LEN);
	rootfscrc = CRC_START;
	memcpy(&tag->rootfsCRC[0], &rootfscrc, sizeof(uint32_t));
	headercrc = crc32(CRC_START, tag, offsetof(struct bcm_tag, headerCRC));
	memcpy(&tag->headerCRC[0], &headercrc, sizeof(uint32_t));

	msync(ptr, sizeof(struct bcm_tag), MS_SYNC|MS_INVALIDATE);
	munmap(ptr, len);
	close(bfd);
	return 0;

err1:
	close(bfd);
err:
	fprintf(stderr, "Error fixing up imagetag header\n");
	return -1;
}


int
trx_check(int imagefd, const char *mtd, char *buf, int *len)
{
    struct bcm_tag *tag = (const struct bcm_tag *) buf;
	int fd;
	uint32_t headerCRC;
	uint32_t imageLen;

	if (strcmp(mtd, "linux") != 0)
		return 1;

	*len = read(imagefd, buf, sizeof(struct bcm_tag));
	if (*len < sizeof(struct bcm_tag)) {
		fprintf(stdout, "Could not get image header, file too small (%d bytes)\n", *len);
		return 0;
	}
	headerCRC = crc32buf(buf, offsetof(struct bcm_tag, headerCRC));
	if (*(uint32_t *)(&tag->headerCRC[0]) != headerCRC) {
  
	  if (quiet < 2) {
		fprintf(stderr, "Bad header CRC got %08lx, calculated %08lx\n",
				*(uint32_t *)(&tag->headerCRC[0]), headerCRC);
		fprintf(stderr, "This is not the correct file format; refusing to flash.\n"
				"Please specify the correct file or use -f to force.\n");
	  }
	  return 0;
	}

	/* check if image fits to mtd device */
	fd = mtd_check_open(mtd);
	if(fd < 0) {
		fprintf(stderr, "Could not open mtd device: %s\n", mtd);
		exit(1);
	}

	imageLen = strntoul(&tag->totalLength[0], NULL, 10, IMAGE_LEN);
	
	if(mtdsize < imageLen) {
		fprintf(stderr, "Image too big for partition: %s\n", mtd);
		close(fd);
		return 0;
	}

	close(fd);
	return 1;
}

int
mtd_fixtrx(const char *mtd, size_t offset)
{
	int fd;
	struct bcm_tag *tag;
	char *buf;
	ssize_t res;
	size_t block_offset;
	uint32_t cfelen, imagelen, imagestart, rootfslen;
	uint32_t imagecrc, rootfscrc, headercrc;
	cfelen = imagelen = imagestart = imagecrc = rootfscrc = headercrc = rootfslen = 0;

	if (quiet < 2)
		fprintf(stderr, "Trying to fix trx header in %s at 0x%x...\n", mtd, offset);

	block_offset = offset & ~(erasesize - 1);
	offset -= block_offset;

	fd = mtd_check_open(mtd);
	if(fd < 0) {
		fprintf(stderr, "Could not open mtd device: %s\n", mtd);
		exit(1);
	}

	if (block_offset + erasesize > mtdsize) {
		fprintf(stderr, "Offset too large, device size 0x%x\n", mtdsize);
		exit(1);
	}

	buf = malloc(erasesize);
	if (!buf) {
		perror("malloc");
		exit(1);
	}

	res = pread(fd, buf, erasesize, block_offset);
	if (res != erasesize) {
		perror("pread");
		exit(1);
	}

	tag = (struct bcm_tag *) (buf + offset);

	cfelen = strntoul(&tag->cfeLength[0], NULL, 10, IMAGE_LEN);
	if (cfelen) {
	  fprintf(stderr, "Non-zero CFE length.  This is currently unsupported.\n");
	  exit(1);
	}

	if (quiet < 2) {
	  fprintf(stderr, "Verifying we actually have an imagetag.\n");
	}

	headercrc = compute_crc32(CRC_START, offset, offsetof(struct bcm_tag, headerCRC), fd);
	if (headercrc != *(uint32_t *)(&tag->headerCRC[0])) {
		fprintf(stderr, "Tag verify failed.  This may not be a valid image.\n");
		exit(1);
	}

	if (quiet < 2) {
	  fprintf(stderr, "Checking current fixed status.\n");
	}

	rootfslen = strntoul(&tag->flashRootLength[0], NULL, 10, IMAGE_LEN);
	if (rootfslen == 0) {
	  if (quiet < 2) 
		fprintf(stderr, "Header already fixed, exiting\n");
	  close(fd);
	  return 0;
	}

	if (quiet < 2) {
	  fprintf(stderr, "Setting root length to 0.\n");
	}

	sprintf(&tag->flashRootLength[0], "%lu", 0);
	strncpy(&tag->totalLength[0], &tag->kernelLength[0], IMAGE_LEN);

	if (quiet < 2) {
	  fprintf(stderr, "Recalculating CRCs.\n");
	}

	imagestart = sizeof(tag);
	memcpy(&tag->imageCRC[0], &tag->kernelCRC[0], CRC_LEN);
	memcpy(&tag->fskernelCRC[0], &tag->kernelCRC[0], CRC_LEN);
	rootfscrc = CRC_START;
	memcpy(&tag->rootfsCRC[0], &rootfscrc, sizeof(uint32_t));
	headercrc = crc32(CRC_START, tag, offsetof(struct bcm_tag, headerCRC));
	memcpy(&tag->headerCRC[0], &headercrc, sizeof(uint32_t));

	if (quiet < 2) {
	  fprintf(stderr, "Erasing imagetag block\n");
	}

	if (mtd_erase_block(fd, block_offset)) {
		fprintf(stderr, "Can't erase block at 0x%x (%s)\n", block_offset, strerror(errno));
		exit(1);
	}

	if (quiet < 2) {
	  fprintf(stderr, "New image crc32: 0x%x, rewriting block\n", 
			  *(uint32_t *)(&tag->imageCRC[0]));
	  fprintf(stderr, "New header crc32: 0x%x, rewriting block\n", headercrc);  
	}

	if (pwrite(fd, buf, erasesize, block_offset) != erasesize) {
		fprintf(stderr, "Error writing block (%s)\n", strerror(errno));
		exit(1);
	}

	if (quiet < 2)
		fprintf(stderr, "Done.\n");

	close (fd);
	sync();
	return 0;

}