LXR linux/arch/sparc/boot/piggyback

   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
  38static unsigned short ld2(char *p)
  39{
  40        return (p[0] << 8) | p[1];
  41}
  42
  43static unsigned int ld4(char *p)
  44{
  45        return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
  46}
  47
  48static 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
  56static 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
  64static void die(char *str)
  65{
  66        perror (str);
  67        exit(1);
  68}
  69
  70int main(int argc,char **argv)
  71{
  72        static char aout_magic[] = { 0x01, 0x03, 0x01, 0x07 };
  73        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}
 138