arch/sparc/boot/piggyback_32.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 <dirent.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <ctype.h>
  27 #include <errno.h>
  28 #include <fcntl.h>
  29 #include <stdio.h>
  30
  31 #include <sys/types.h>
  32 #include <sys/stat.h>
  33
  34 /*
  35  * Note: run this on an a.out kernel (use elftoaout for it),
  36  * as PROM looks for a.out image only.
  37  */
  38
  39 /* read two bytes as big endian */
  40 static unsigned short ld2(char *p)
  41 {
  42         return (p[0] << 8) | p[1];
  43 }
  44
  45 /* read 4 bytes as big endian */
  46 static unsigned int ld4(char *p)
  47 {
  48         return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
  49 }
  50
  51 /* save 4 bytes as big endian */
  52 static void st4(char *p, unsigned int x)
  53 {
  54         p[0] = x >> 24;
  55         p[1] = x >> 16;
  56         p[2] = x >> 8;
  57         p[3] = x;
  58 }
  59
  60 static void die(const char *str)
  61 {
  62         perror(str);
  63         exit(1);
  64 }
  65
  66 static void usage(void)
  67 {
  68         /* fs_img.gz is an image of initial ramdisk. */
  69         fprintf(stderr, "Usage: piggyback vmlinux.aout System.map fs_img.gz\n");
  70         fprintf(stderr, "\tKernel image will be modified in place.\n");
  71         exit(1);
  72 }
  73
  74 static int start_line(const char *line)
  75 {
  76         if (strcmp(line + 8, " T _start\n") == 0)
  77                 return 1;
  78         else if (strcmp(line + 16, " T _start\n") == 0)
  79                 return 1;
  80         return 0;
  81 }
  82
  83 static int end_line(const char *line)
  84 {
  85         if (strcmp(line + 8, " A _end\n") == 0)
  86                 return 1;
  87         else if (strcmp (line + 16, " A _end\n") == 0)
  88                 return 1;
  89         return 0;
  90 }
  91
  92 /*
  93  * Find address for start and end in System.map.
  94  * The file looks like this:
  95  * f0004000 T _start
  96  * f0379f79 A _end
  97  * 1234567890123456
  98  * ^coloumn 1
  99  * There is support for 64 bit addresses too.
 100  *
 101  * Return 0 if either start or end is not found
 102  */
 103 static int get_start_end(const char *filename, unsigned int *start, unsigned int *end)
 104 {
 105         FILE *map;
 106         char buffer[1024];
 107
 108         *start = 0;
 109         *end = 0;
 110         map = fopen(filename, "r");
 111         if (!map)
 112                 die(filename);
 113         while (fgets(buffer, 1024, map)) {
 114                 if (start_line(buffer))
 115                         *start = strtoul(buffer, NULL, 16);
 116                 else if (end_line(buffer))
 117                         *end = strtoul(buffer, NULL, 16);
 118         }
 119         fclose (map);
 120
 121         if (*start == 0 || *end == 0)
 122                 return 0;
 123
 124         return 1;
 125 }
 126
 127 int main(int argc,char **argv)
 128 {
 129         static char aout_magic[] = { 0x01, 0x03, 0x01, 0x07 };
 130         char buffer[1024], *q, *r;
 131         unsigned int i, j, k, start, end, offset;
 132         struct stat s;
 133         int image, tail;
 134
 135         if (argc != 4)
 136                 usage();
 137         if (stat (argv[3], &s) < 0)
 138                 die(argv[3]);
 139
 140         if (!get_start_end(argv[2], &start, &end)) {
 141                 fprintf (stderr, "Could not determine start and end from %s\n", argv[2]);
 142                 exit(1);
 143         }
 144         if ((image = open(argv[1], O_RDWR)) < 0)
 145                 die(argv[1]);
 146         if (read(image, buffer, 512) != 512)
 147                 die(argv[1]);
 148         if (memcmp (buffer, "\177ELF", 4) == 0) {
 149                 q = buffer + ld4(buffer + 28);
 150                 i = ld4(q + 4) + ld4(buffer + 24) - ld4(q + 8);
 151                 if (lseek(image, i, 0) < 0)
 152                         die("lseek");
 153                 if (read(image, buffer, 512) != 512)
 154                         die(argv[1]);
 155                 j = 0;
 156         } else if (memcmp(buffer, aout_magic, 4) == 0) {
 157                 i = j = 32;
 158         } else {
 159                 fprintf (stderr, "Not ELF nor a.out. Don't blame me.\n");
 160                 exit(1);
 161         }
 162         k = i;
 163         i += (ld2(buffer + j + 2) << 2) - 512;
 164         if (lseek(image, i, 0) < 0)
 165                 die("lseek");
 166         if (read(image, buffer, 1024) != 1024)
 167                 die(argv[1]);
 168         for (q = buffer, r = q + 512; q < r; q += 4) {
 169                 if (*q == 'H' && q[1] == 'd' && q[2] == 'r' && q[3] == 'S')
 170                         break;
 171         }
 172         if (q == r) {
 173                 fprintf (stderr, "Couldn't find headers signature in the kernel.\n");
 174                 exit(1);
 175         }
 176         offset = i + (q - buffer) + 10;
 177         if (lseek(image, offset, 0) < 0)
 178                 die("lseek");
 179
 180         st4(buffer, 0);
 181         st4(buffer + 4, 0x01000000);
 182         st4(buffer + 8, (end + 32 + 4095) & ~4095);
 183         st4(buffer + 12, s.st_size);
 184
 185         if (write(image, buffer + 2, 14) != 14)
 186                 die(argv[1]);
 187         if (lseek(image, k - start + ((end + 32 + 4095) & ~4095), 0) < 0)
 188                 die("lseek");
 189         if ((tail = open(argv[3],O_RDONLY)) < 0)
 190                 die(argv[3]);
 191         while ((i = read (tail, buffer, 1024)) > 0)
 192                 if (write(image, buffer, i) != i)
 193                         die(argv[1]);
 194         if (close(image) < 0)
 195                 die("close");
 196         if (close(tail) < 0)
 197                 die("close");
 198         return 0;
 199 }