linux-old/arch/i386/boot/tools/build.c
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   1/*
   2 *  $Id: build.c,v 1.5 1997/05/19 12:29:58 mj 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
  38typedef unsigned char byte;
  39typedef unsigned short word;
  40typedef 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
  48byte buf[1024];
  49int fd;
  50int is_big_kernel;
  51
  52void 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
  61void 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
  67void usage(void)
  68{
  69        die("Usage: build [-b] bootsect setup system [rootdev] [> image]");
  70}
  71
  72int 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        /* 0x28000*16 = 2.5 MB, conservative estimate for the current maximum */
 154        if (sys_size > (is_big_kernel ? 0x28000 : DEF_SYSSIZE))
 155                die("System is too big. Try using %smodules.",
 156                        is_big_kernel ? "" : "bzImage or ");
 157        if (sys_size > 0xefff)
 158                fprintf(stderr,"warning: kernel is too big for standalone boot "
 159                    "from floppy\n");
 160        while (sz > 0) {
 161                int l, n;
 162
 163                l = (sz > sizeof(buf)) ? sizeof(buf) : sz;
 164                if ((n=read(fd, buf, l)) != l) {
 165                        if (n < 0)
 166                                die("Error reading %s: %m", argv[3]);
 167                        else
 168                                die("%s: Unexpected EOF", argv[3]);
 169                }
 170                if (write(1, buf, l) != l)
 171                        die("Write failed");
 172                sz -= l;
 173        }
 174        close(fd);
 175
 176        if (lseek(1, 497, SEEK_SET) != 497)                 /* Write sizes to the bootsector */
 177                die("Output: seek failed");
 178        buf[0] = setup_sectors;
 179        if (write(1, buf, 1) != 1)
 180                die("Write of setup sector count failed");
 181        if (lseek(1, 500, SEEK_SET) != 500)
 182                die("Output: seek failed");
 183        buf[0] = (sys_size & 0xff);
 184        buf[1] = ((sys_size >> 8) & 0xff);
 185        if (write(1, buf, 2) != 2)
 186                die("Write of image length failed");
 187
 188        return 0;                                           /* Everything is OK */
 189}
 190