text: /*
   * uimage_padhdr.c : add zero paddings after the tail of uimage header
   *
   * Copyright (C) 2019 NOGUCHI Hiroshi <drvlabo@gmail.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License,
   * version 2 as published by the Free Software Foundation.
   *
   * 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.
   */
  
  #include <stdio.h>
  #include <errno.h>
  #include <unistd.h>
  #include <stdlib.h>
  #include <string.h>
  #include <fcntl.h>
  #include <sys/stat.h>
  #include <arpa/inet.h>
  #include <zlib.h>
  
  
  /* from u-boot/include/image.h */
  #define IH_MAGIC	0x27051956	/* Image Magic Number		*/
  #define IH_NMLEN		32	/* Image Name Length		*/
  
  /*
   * Legacy format image header,
   * all data in network byte order (aka natural aka bigendian).
   */
  typedef struct image_header {
  	uint32_t	ih_magic;	/* Image Header Magic Number	*/
  	uint32_t	ih_hcrc;	/* Image Header CRC Checksum	*/
  	uint32_t	ih_time;	/* Image Creation Timestamp	*/
  	uint32_t	ih_size;	/* Image Data Size		*/
  	uint32_t	ih_load;	/* Data	 Load  Address		*/
  	uint32_t	ih_ep;		/* Entry Point Address		*/
  	uint32_t	ih_dcrc;	/* Image Data CRC Checksum	*/
  	uint8_t		ih_os;		/* Operating System		*/
  	uint8_t		ih_arch;	/* CPU architecture		*/
  	uint8_t		ih_type;	/* Image Type			*/
  	uint8_t		ih_comp;	/* Compression Type		*/
  	uint8_t		ih_name[IH_NMLEN];	/* Image Name		*/
  } image_header_t;
  
  
  /* default padding size */
  #define	IH_PAD_BYTES		(32)
  
  
  static void usage(char *prog)
  {
  	fprintf(stderr,
  		"%s -i <input_uimage_file> -o <output_file> [-l <padding bytes>]\n",
  		prog);
  }
  
  int main(int argc, char *argv[])
  {
  	struct stat statbuf;
  	u_int8_t *filebuf;
  	int ifd;
  	int ofd;
  	ssize_t rsz;
  	u_int32_t crc_recalc;
  	image_header_t *imgh;
  	int opt;
  	char *infname = NULL;
  	char *outfname = NULL;
  	int padsz = IH_PAD_BYTES;
  	int ltmp;
  
  	while ((opt = getopt(argc, argv, "i:o:l:")) != -1) {
  		switch (opt) {
  		case 'i':
  			infname = optarg;
  			break;
  		case 'o':
  			outfname = optarg;
  			break;
  		case 'l':
  			ltmp = strtol(optarg, NULL, 0);
  			if (ltmp > 0)
  				padsz = ltmp;
  			break;
  		default:
  			break;
  		}
  	}
  
  	if (!infname || !outfname) {
  		usage(argv[0]);
  		exit(1);
  	}
  
  	ifd = open(infname, O_RDONLY);
  	if (ifd < 0) {
  		fprintf(stderr,
  			"could not open input file. (errno = %d)\n", errno);
  		exit(1);
  	}
  
  	ofd = open(outfname, O_WRONLY | O_CREAT, 0644);
  	if (ofd < 0) {
  		fprintf(stderr,
  			"could not open output file. (errno = %d)\n", errno);
  		exit(1);
  	}
  
  	if (fstat(ifd, &statbuf) < 0) {
  		fprintf(stderr,
  			"could not fstat input file. (errno = %d)\n", errno);
  		exit(1);
  	}
  
  	filebuf = malloc(statbuf.st_size + padsz);
  	if (!filebuf) {
  		fprintf(stderr, "buffer allocation failed\n");
  		exit(1);
  	}
  
  	rsz = read(ifd, filebuf, sizeof(*imgh));
  	if (rsz != sizeof(*imgh)) {
  		fprintf(stderr,
  			"could not read input file (errno = %d).\n", errno);
  		exit(1);
  	}
  
  	memset(&(filebuf[sizeof(*imgh)]), 0, padsz);
  
  	rsz = read(ifd, &(filebuf[sizeof(*imgh) + padsz]),
  				statbuf.st_size - sizeof(*imgh));
  	if (rsz != (int32_t)(statbuf.st_size - sizeof(*imgh))) {
  		fprintf(stderr,
  			"could not read input file (errno = %d).\n", errno);
  		exit(1);
  	}
  
  	imgh = (image_header_t *)filebuf;
  
  	imgh->ih_hcrc = 0;
  	crc_recalc = crc32(0, filebuf, sizeof(*imgh) + padsz);
  	imgh->ih_hcrc = htonl(crc_recalc);
  
  	rsz = write(ofd, filebuf, statbuf.st_size + padsz);
  	if (rsz != (int32_t)statbuf.st_size + padsz) {
  		fprintf(stderr,
  			"could not write output file (errnor = %d).\n", errno);
  		exit(1);
  	}
  
  	return 0;
  }
  