arch/x86_64/boot/tools/build.c

   1 /*
   2  *  $Id: build.c,v 1.3 2001/06/26 15:14:50 pavel Exp $
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *  Copyright (C) 1997 Martin Mares
   6  */
   7
   8 /*
   9  * This file builds a disk-image from three different files:
  10  *
  11  * - bootsect: exactly 512 bytes of 8086 machine code, loads the rest
  12  * - setup: 8086 machine code, sets up system parm
  13  * - system: 80386 code for actual system
  14  *
  15  * It does some checking that all files are of the correct type, and
  16  * just writes the result to stdout, removing headers and padding to
  17  * the right amount. It also writes some system data to stderr.
  18  */
  19
  20 /*
  21  * Changes by tytso to allow root device specification
  22  * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
  23  * Cross compiling fixes by Gertjan van Wingerde, July 1996
  24  * Rewritten by Martin Mares, April 1997
  25  */
  26
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <stdlib.h>
  30 #include <stdarg.h>
  31 #include <sys/types.h>
  32 #include <sys/stat.h>
  33 #include <sys/sysmacros.h>
  34 #include <unistd.h>
  35 #include <fcntl.h>
  36 #include <asm/boot.h>
  37
  38 typedef unsigned char byte;
  39 typedef unsigned short word;
  40 typedef unsigned long u32;
  41
  42 #define DEFAULT_MAJOR_ROOT 0
  43 #define DEFAULT_MINOR_ROOT 0
  44
  45 /* Minimal number of setup sectors (see also bootsect.S) */
  46 #define SETUP_SECTS 4
  47
  48 byte buf[1024];
  49 int fd;
  50 int is_big_kernel;
  51
  52 void die(const char * str, ...)
  53 {
  54         va_list args;
  55         va_start(args, str);
  56         vfprintf(stderr, str, args);
  57         fputc('\n', stderr);
  58         exit(1);
  59 }
  60
  61 void file_open(const char *name)
  62 {
  63         if ((fd = open(name, O_RDONLY, 0)) < 0)
  64                 die("Unable to open `%s': %m", name);
  65 }
  66
  67 void usage(void)
  68 {
  69         die("Usage: build [-b] bootsect setup system [rootdev] [> image]");
  70 }
  71
  72 int main(int argc, char ** argv)
  73 {
  74         unsigned int i, c, sz, setup_sectors;
  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         /* 0x40000*16 = 4.0 MB, reasonable estimate for the current maximum */
 154         if (sys_size > (is_big_kernel ? 0x40000 : DEF_SYSSIZE))
 155                 die("System is too big. Try using %smodules.",
 156                         is_big_kernel ? "" : "bzImage or ");
 157         while (sz > 0) {
 158                 int l, n;
 159
 160                 l = (sz > sizeof(buf)) ? sizeof(buf) : sz;
 161                 if ((n=read(fd, buf, l)) != l) {
 162                         if (n < 0)
 163                                 die("Error reading %s: %m", argv[3]);
 164                         else
 165                                 die("%s: Unexpected EOF", argv[3]);
 166                 }
 167                 if (write(1, buf, l) != l)
 168                         die("Write failed");
 169                 sz -= l;
 170         }
 171         close(fd);
 172
 173         if (lseek(1, 497, SEEK_SET) != 497)                 /* Write sizes to the bootsector */
 174                 die("Output: seek failed");
 175         buf[0] = setup_sectors;
 176         if (write(1, buf, 1) != 1)
 177                 die("Write of setup sector count failed");
 178         if (lseek(1, 500, SEEK_SET) != 500)
 179                 die("Output: seek failed");
 180         buf[0] = (sys_size & 0xff);
 181         buf[1] = ((sys_size >> 8) & 0xff);
 182         if (write(1, buf, 2) != 2)
 183                 die("Write of image length failed");
 184
 185         return 0;                                           /* Everything is OK */
 186 }