release/src-rt-6.x/linux/linux-2.6/arch/i386/boot/tools/build.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 1997 Martin Mares
   4  */
   5
   6 /*
   7  * This file builds a disk-image from three different files:
   8  *
   9  * - bootsect: compatibility mbr which prints an error message if
  10  *             someone tries to boot the kernel directly.
  11  * - setup: 8086 machine code, sets up system parm
  12  * - system: 80386 code for actual system
  13  *
  14  * It does some checking that all files are of the correct type, and
  15  * just writes the result to stdout, removing headers and padding to
  16  * the right amount. It also writes some system data to stderr.
  17  */
  18
  19 /*
  20  * Changes by tytso to allow root device specification
  21  * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
  22  * Cross compiling fixes by Gertjan van Wingerde, July 1996
  23  * Rewritten by Martin Mares, April 1997
  24  */
  25
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <stdlib.h>
  29 #include <stdarg.h>
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32 #include <sys/sysmacros.h>
  33 #include <unistd.h>
  34 #include <fcntl.h>
  35 #include <asm/boot.h>
  36
  37 typedef unsigned char byte;
  38 typedef unsigned short word;
  39 typedef unsigned long u32;
  40
  41 #define DEFAULT_MAJOR_ROOT 0
  42 #define DEFAULT_MINOR_ROOT 0
  43
  44 /* Minimal number of setup sectors (see also bootsect.S) */
  45 #define SETUP_SECTS 4
  46
  47 byte buf[1024];
  48 int fd;
  49 int is_big_kernel;
  50
  51 void die(const char * str, ...)
  52 {
  53         va_list args;
  54         va_start(args, str);
  55         vfprintf(stderr, str, args);
  56         fputc('\n', stderr);
  57         exit(1);
  58 }
  59
  60 void file_open(const char *name)
  61 {
  62         if ((fd = open(name, O_RDONLY, 0)) < 0)
  63                 die("Unable to open `%s': %m", name);
  64 }
  65
  66 void usage(void)
  67 {
  68         die("Usage: build [-b] bootsect setup system [rootdev] [> image]");
  69 }
  70
  71 int main(int argc, char ** argv)
  72 {
  73         unsigned int i, sz, setup_sectors;
  74         int c;
  75         u32 sys_size;
  76         byte major_root, minor_root;
  77         struct stat sb;
  78
  79         if (argc > 2 && !strcmp(argv[1], "-b"))
  80           {
  81             is_big_kernel = 1;
  82             argc--, argv++;
  83           }
  84         if ((argc < 4) || (argc > 5))
  85                 usage();
  86         if (argc > 4) {
  87                 if (!strcmp(argv[4], "CURRENT")) {
  88                         if (stat("/", &sb)) {
  89                                 perror("/");
  90                                 die("Couldn't stat /");
  91                         }
  92                         major_root = major(sb.st_dev);
  93                         minor_root = minor(sb.st_dev);
  94                 } else if (strcmp(argv[4], "FLOPPY")) {
  95                         if (stat(argv[4], &sb)) {
  96                                 perror(argv[4]);
  97                                 die("Couldn't stat root device.");
  98                         }
  99                         major_root = major(sb.st_rdev);
 100                         minor_root = minor(sb.st_rdev);
 101                 } else {
 102                         major_root = 0;
 103                         minor_root = 0;
 104                 }
 105         } else {
 106                 major_root = DEFAULT_MAJOR_ROOT;
 107                 minor_root = DEFAULT_MINOR_ROOT;
 108         }
 109         fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
 110
 111         file_open(argv[1]);
 112         i = read(fd, buf, sizeof(buf));
 113         fprintf(stderr,"Boot sector %d bytes.\n",i);
 114         if (i != 512)
 115                 die("Boot block must be exactly 512 bytes");
 116         if (buf[510] != 0x55 || buf[511] != 0xaa)
 117                 die("Boot block hasn't got boot flag (0xAA55)");
 118         buf[508] = minor_root;
 119         buf[509] = major_root;
 120         if (write(1, buf, 512) != 512)
 121                 die("Write call failed");
 122         close (fd);
 123
 124         file_open(argv[2]);                                 /* Copy the setup code */
 125         for (i=0 ; (c=read(fd, buf, sizeof(buf)))>0 ; i+=c )
 126                 if (write(1, buf, c) != c)
 127                         die("Write call failed");
 128         if (c != 0)
 129                 die("read-error on `setup'");
 130         close (fd);
 131
 132         setup_sectors = (i + 511) / 512;        /* Pad unused space with zeros */
 133         /* for compatibility with ancient versions of LILO. */
 134         if (setup_sectors < SETUP_SECTS)
 135                 setup_sectors = SETUP_SECTS;
 136         fprintf(stderr, "Setup is %d bytes.\n", i);
 137         memset(buf, 0, sizeof(buf));
 138         while (i < setup_sectors * 512) {
 139                 c = setup_sectors * 512 - i;
 140                 if (c > sizeof(buf))
 141                         c = sizeof(buf);
 142                 if (write(1, buf, c) != c)
 143                         die("Write call failed");
 144                 i += c;
 145         }
 146
 147         file_open(argv[3]);
 148         if (fstat (fd, &sb))
 149                 die("Unable to stat `%s': %m", argv[3]);
 150         sz = sb.st_size;
 151         fprintf (stderr, "System is %d kB\n", sz/1024);
 152         sys_size = (sz + 15) / 16;
 153         if (!is_big_kernel && sys_size > DEF_SYSSIZE)
 154                 die("System is too big. Try using bzImage or modules.");
 155         while (sz > 0) {
 156                 int l, n;
 157
 158                 l = (sz > sizeof(buf)) ? sizeof(buf) : sz;
 159                 if ((n=read(fd, buf, l)) != l) {
 160                         if (n < 0)
 161                                 die("Error reading %s: %m", argv[3]);
 162                         else
 163                                 die("%s: Unexpected EOF", argv[3]);
 164                 }
 165                 if (write(1, buf, l) != l)
 166                         die("Write failed");
 167                 sz -= l;
 168         }
 169         close(fd);
 170
 171         if (lseek(1, 497, SEEK_SET) != 497)                 /* Write sizes to the bootsector */
 172                 die("Output: seek failed");
 173         buf[0] = setup_sectors;
 174         if (write(1, buf, 1) != 1)
 175                 die("Write of setup sector count failed");
 176         if (lseek(1, 500, SEEK_SET) != 500)
 177                 die("Output: seek failed");
 178         buf[0] = (sys_size & 0xff);
 179         buf[1] = ((sys_size >> 8) & 0xff);
 180         buf[2] = ((sys_size >> 16) & 0xff);
 181         buf[3] = ((sys_size >> 24) & 0xff);
 182         if (write(1, buf, 4) != 4)
 183                 die("Write of image length failed");
 184
 185         return 0;                                           /* Everything is OK */
 186 }