arch/sparc/boot/piggyback.c

   1 /*
   2    Simple utility to make a single-image install kernel with initial ramdisk
   3    for Sparc tftpbooting without need to set up nfs.
   4
   5    Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   6    Pete Zaitcev <zaitcev@yahoo.com> endian fixes for cross-compiles, 2000.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  21
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <ctype.h>
  25 #include <errno.h>
  26 #include <fcntl.h>
  27 #include <dirent.h>
  28 #include <unistd.h>
  29 #include <stdlib.h>
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32
  33 /*
  34  * Note: run this on an a.out kernel (use elftoaout for it),
  35  * as PROM looks for a.out image only.
  36  */
  37
  38 unsigned short ld2(char *p)
  39 {
  40         return (p[0] << 8) | p[1];
  41 }
  42
  43 unsigned int ld4(char *p)
  44 {
  45         return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
  46 }
  47
  48 void st4(char *p, unsigned int x)
  49 {
  50         p[0] = x >> 24;
  51         p[1] = x >> 16;
  52         p[2] = x >> 8;
  53         p[3] = x;
  54 }
  55
  56 void usage(void)
  57 {
  58         /* fs_img.gz is an image of initial ramdisk. */
  59         fprintf(stderr, "Usage: piggyback vmlinux.aout System.map fs_img.gz\n");
  60         fprintf(stderr, "\tKernel image will be modified in place.\n");
  61         exit(1);
  62 }
  63
  64 void die(char *str)
  65 {
  66         perror (str);
  67         exit(1);
  68 }
  69
  70 int main(int argc,char **argv)
  71 {
  72         static char aout_magic[] = { 0x01, 0x03, 0x01, 0x07 };
  73         unsigned char buffer[1024], *q, *r;
  74         unsigned int i, j, k, start, end, offset;
  75         FILE *map;
  76         struct stat s;
  77         int image, tail;
  78
  79         if (argc != 4) usage();
  80         start = end = 0;
  81         if (stat (argv[3], &s) < 0) die (argv[3]);
  82         map = fopen (argv[2], "r");
  83         if (!map) die(argv[2]);
  84         while (fgets (buffer, 1024, map)) {
  85                 if (!strcmp (buffer + 8, " T start\n") || !strcmp (buffer + 16, " T start\n"))
  86                         start = strtoul (buffer, NULL, 16);
  87                 else if (!strcmp (buffer + 8, " A end\n") || !strcmp (buffer + 16, " A end\n"))
  88                         end = strtoul (buffer, NULL, 16);
  89         }
  90         fclose (map);
  91         if (!start || !end) {
  92                 fprintf (stderr, "Could not determine start and end from System.map\n");
  93                 exit(1);
  94         }
  95         if ((image = open(argv[1],O_RDWR)) < 0) die(argv[1]);
  96         if (read(image,buffer,512) != 512) die(argv[1]);
  97         if (memcmp (buffer, "\177ELF", 4) == 0) {
  98                 q = buffer + ld4(buffer + 28);
  99                 i = ld4(q + 4) + ld4(buffer + 24) - ld4(q + 8);
 100                 if (lseek(image,i,0) < 0) die("lseek");
 101                 if (read(image,buffer,512) != 512) die(argv[1]);
 102                 j = 0;
 103         } else if (memcmp(buffer, aout_magic, 4) == 0) {
 104                 i = j = 32;
 105         } else {
 106                 fprintf (stderr, "Not ELF nor a.out. Don't blame me.\n");
 107                 exit(1);
 108         }
 109         k = i;
 110         i += (ld2(buffer + j + 2)<<2) - 512;
 111         if (lseek(image,i,0) < 0) die("lseek");
 112         if (read(image,buffer,1024) != 1024) die(argv[1]);
 113         for (q = buffer, r = q + 512; q < r; q += 4) {
 114                 if (*q == 'H' && q[1] == 'd' && q[2] == 'r' && q[3] == 'S')
 115                         break;
 116         }
 117         if (q == r) {
 118                 fprintf (stderr, "Couldn't find headers signature in the kernel.\n");
 119                 exit(1);
 120         }
 121         offset = i + (q - buffer) + 10;
 122         if (lseek(image, offset, 0) < 0) die ("lseek");
 123
 124         st4(buffer, 0);
 125         st4(buffer + 4, 0x01000000);
 126         st4(buffer + 8, (end + 32 + 4095) & ~4095);
 127         st4(buffer + 12, s.st_size);
 128
 129         if (write(image,buffer+2,14) != 14) die (argv[1]);
 130         if (lseek(image, k - start + ((end + 32 + 4095) & ~4095), 0) < 0) die ("lseek");
 131         if ((tail = open(argv[3],O_RDONLY)) < 0) die(argv[3]);
 132         while ((i = read (tail,buffer,1024)) > 0)
 133                 if (write(image,buffer,i) != i) die (argv[1]);
 134         if (close(image) < 0) die("close");
 135         if (close(tail) < 0) die("close");
 136         return 0;
 137 }