tools/patch-image/src/patch-dtb.c

   1 /*
   2  * patch-dtb.c - patch a dtb into an image
   3  *
   4  * Copyright (C) 2006 Felix Fietkau <nbd@nbd.name>
   5  * Copyright (C) 2012 John Crispin <blogic@openwrt.org>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  20  *
  21  * based on patch-cmdline.c
  22  */
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <stddef.h>
  27 #include <unistd.h>
  28 #include <fcntl.h>
  29 #include <sys/mman.h>
  30 #include <sys/stat.h>
  31 #include <string.h>
  32
  33 #define SEARCH_SPACE    (16 * 1024)
  34 #define DTB_MAX (16 * 1024)
  35
  36 int main(int argc, char **argv)
  37 {
  38         int fd, fddtb, found = 0, len, ret = -1;
  39         char *ptr, *ptrdtb, *p;
  40         struct stat s;
  41
  42         if (argc != 3) {
  43                 fprintf(stderr, "Usage: %s <file> <dtb>\n", argv[0]);
  44                 goto err1;
  45         }
  46         fddtb = open(argv[1], O_RDONLY);
  47         if (!fddtb)
  48                 goto err1;
  49
  50         if (stat(argv[2], &s)) {
  51                 fprintf(stderr, "DTB not found\n");
  52                 goto err1;
  53         }
  54
  55         len = s.st_size;
  56         if (len + 8 > DTB_MAX) {
  57                 fprintf(stderr, "DTB too big\n");
  58                 goto err1;
  59         }
  60
  61         if (((fddtb = open(argv[2], O_RDONLY)) < 0) ||
  62                 (ptrdtb = (char *) mmap(0, DTB_MAX, PROT_READ, MAP_SHARED, fddtb, 0)) == (void *) (-1)) {
  63                 fprintf(stderr, "Could not open DTB");
  64                 goto err2;
  65         }
  66
  67         if (((fd = open(argv[1], O_RDWR)) < 0) ||
  68                 (ptr = (char *) mmap(0, SEARCH_SPACE + DTB_MAX, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == (void *) (-1)) {
  69                 fprintf(stderr, "Could not open kernel image");
  70                 goto err3;
  71         }
  72
  73         for (p = ptr; p < (ptr + SEARCH_SPACE); p += 4) {
  74                 if (memcmp(p, "OWRTDTB:", 8) == 0) {
  75                         found = 1;
  76                         p += 8;
  77                         break;
  78                 }
  79         }
  80         if (!found) {
  81                 fprintf(stderr, "DTB marker not found!\n");
  82                 goto err4;
  83         }
  84
  85         memset(p, 0, DTB_MAX - 8);
  86         memcpy(p, ptrdtb, len);
  87         msync(p, len, MS_SYNC|MS_INVALIDATE);
  88         ret = 0;
  89
  90 err4:
  91         munmap((void *) ptr, len);
  92 err3:
  93         if (fd > 0)
  94                 close(fd);
  95         munmap((void *) ptrdtb, len);
  96 err2:
  97         if (fddtb > 0)
  98                 close(fddtb);
  99 err1:
 100         return ret;
 101 }