utils/ypr0tools/extract_section.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2011 Thomas Martitz
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #include <unistd.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <stdarg.h>
  29
  30 /* A simple replacement program for (
  31  * dd if=$file1 of=$file2 bs=1 skip=$offset count=$size
  32  *
  33  * Written because byte-size operations with dd are unbearably slow.
  34  */
  35
  36 void usage(void)
  37 {
  38     fprintf(stderr, "Usage: extract_section <romfile> <outfile> <offset> <byte count>\n");
  39     exit(1);
  40 }
  41
  42 void die(const char* fmt, ...)
  43 {
  44     va_list ap;
  45     va_start(ap, fmt);
  46     vfprintf(stderr, fmt, ap);
  47     va_end(ap);
  48     exit(1);
  49 }
  50
  51 int main(int argc, const char* argv[])
  52 {
  53     if (argc != 5)
  54         usage();
  55
  56     int ifd, ofd;
  57     ssize_t size = atol(argv[4]);
  58     long skip = atol(argv[3]);
  59
  60     if (!size)
  61         die("invalid byte count\n");
  62
  63     ifd = open(argv[1], O_RDONLY);
  64     if (ifd < 0)
  65         die("Could not open %s for reading!\n", argv[1]);
  66
  67     ofd = open(argv[2], O_WRONLY|O_CREAT|O_TRUNC, 0666);
  68     if (ofd < 0)
  69         die("Could not create %s\n", argv[2]);
  70
  71     void *buf = malloc(size);
  72     if (!buf) die("OOM\n");
  73
  74     lseek(ifd, skip, SEEK_SET);
  75     lseek(ofd, 0, SEEK_SET);
  76     if (read(ifd, buf, size) != size)
  77         die("Read failed\n");
  78     if (write(ofd, buf, size) != size)
  79         die("write failed\n");
  80
  81     close(ifd);
  82     close(ofd);
  83
  84     exit(EXIT_SUCCESS);
  85 }