src/uimage_padhdr.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * uimage_padhdr.c : add zero paddings after the tail of uimage header
   4  *
   5  * Copyright (C) 2019 NOGUCHI Hiroshi <drvlabo@gmail.com>
   6  */
   7
   8 #include <stdio.h>
   9 #include <errno.h>
  10 #include <unistd.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <fcntl.h>
  14 #include <sys/stat.h>
  15 #include <arpa/inet.h>
  16 #include <zlib.h>
  17
  18
  19 /* from u-boot/include/image.h */
  20 #define IH_MAGIC        0x27051956      /* Image Magic Number           */
  21 #define IH_NMLEN                32      /* Image Name Length            */
  22
  23 /*
  24  * Legacy format image header,
  25  * all data in network byte order (aka natural aka bigendian).
  26  */
  27 typedef struct image_header {
  28         uint32_t        ih_magic;       /* Image Header Magic Number    */
  29         uint32_t        ih_hcrc;        /* Image Header CRC Checksum    */
  30         uint32_t        ih_time;        /* Image Creation Timestamp     */
  31         uint32_t        ih_size;        /* Image Data Size              */
  32         uint32_t        ih_load;        /* Data  Load  Address          */
  33         uint32_t        ih_ep;          /* Entry Point Address          */
  34         uint32_t        ih_dcrc;        /* Image Data CRC Checksum      */
  35         uint8_t         ih_os;          /* Operating System             */
  36         uint8_t         ih_arch;        /* CPU architecture             */
  37         uint8_t         ih_type;        /* Image Type                   */
  38         uint8_t         ih_comp;        /* Compression Type             */
  39         uint8_t         ih_name[IH_NMLEN];      /* Image Name           */
  40 } image_header_t;
  41
  42
  43 /* default padding size */
  44 #define IH_PAD_BYTES            (32)
  45
  46
  47 static void usage(char *prog)
  48 {
  49         fprintf(stderr,
  50                 "%s -i <input_uimage_file> -o <output_file> [-l <padding bytes>]\n",
  51                 prog);
  52 }
  53
  54 int main(int argc, char *argv[])
  55 {
  56         struct stat statbuf;
  57         u_int8_t *filebuf;
  58         int ifd;
  59         int ofd;
  60         ssize_t rsz;
  61         u_int32_t crc_recalc;
  62         image_header_t *imgh;
  63         int opt;
  64         char *infname = NULL;
  65         char *outfname = NULL;
  66         int padsz = IH_PAD_BYTES;
  67         int ltmp;
  68
  69         while ((opt = getopt(argc, argv, "i:o:l:")) != -1) {
  70                 switch (opt) {
  71                 case 'i':
  72                         infname = optarg;
  73                         break;
  74                 case 'o':
  75                         outfname = optarg;
  76                         break;
  77                 case 'l':
  78                         ltmp = strtol(optarg, NULL, 0);
  79                         if (ltmp > 0)
  80                                 padsz = ltmp;
  81                         break;
  82                 default:
  83                         break;
  84                 }
  85         }
  86
  87         if (!infname || !outfname) {
  88                 usage(argv[0]);
  89                 exit(1);
  90         }
  91
  92         ifd = open(infname, O_RDONLY);
  93         if (ifd < 0) {
  94                 fprintf(stderr,
  95                         "could not open input file. (errno = %d)\n", errno);
  96                 exit(1);
  97         }
  98
  99         ofd = open(outfname, O_WRONLY | O_CREAT, 0644);
 100         if (ofd < 0) {
 101                 fprintf(stderr,
 102                         "could not open output file. (errno = %d)\n", errno);
 103                 exit(1);
 104         }
 105
 106         if (fstat(ifd, &statbuf) < 0) {
 107                 fprintf(stderr,
 108                         "could not fstat input file. (errno = %d)\n", errno);
 109                 exit(1);
 110         }
 111
 112         filebuf = malloc(statbuf.st_size + padsz);
 113         if (!filebuf) {
 114                 fprintf(stderr, "buffer allocation failed\n");
 115                 exit(1);
 116         }
 117
 118         rsz = read(ifd, filebuf, sizeof(*imgh));
 119         if (rsz != sizeof(*imgh)) {
 120                 fprintf(stderr,
 121                         "could not read input file (errno = %d).\n", errno);
 122                 exit(1);
 123         }
 124
 125         memset(&(filebuf[sizeof(*imgh)]), 0, padsz);
 126
 127         rsz = read(ifd, &(filebuf[sizeof(*imgh) + padsz]),
 128                                 statbuf.st_size - sizeof(*imgh));
 129         if (rsz != (int32_t)(statbuf.st_size - sizeof(*imgh))) {
 130                 fprintf(stderr,
 131                         "could not read input file (errno = %d).\n", errno);
 132                 exit(1);
 133         }
 134
 135         imgh = (image_header_t *)filebuf;
 136
 137         imgh->ih_hcrc = 0;
 138         crc_recalc = crc32(0, filebuf, sizeof(*imgh) + padsz);
 139         imgh->ih_hcrc = htonl(crc_recalc);
 140
 141         rsz = write(ofd, filebuf, statbuf.st_size + padsz);
 142         if (rsz != (int32_t)statbuf.st_size + padsz) {
 143                 fprintf(stderr,
 144                         "could not write output file (errnor = %d).\n", errno);
 145                 exit(1);
 146         }
 147
 148         return 0;
 149 }