linux/arch/x86/boot/tools/build.c
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   1/*
   2 *  Copyright (C) 1991, 1992  Linus Torvalds
   3 *  Copyright (C) 1997 Martin Mares
   4 *  Copyright (C) 2007 H. Peter Anvin
   5 */
   6
   7/*
   8 * This file builds a disk-image from two different files:
   9 *
  10 * - setup: 8086 machine code, sets up system parm
  11 * - system: 80386 code for actual system
  12 *
  13 * It does some checking that all files are of the correct type, and
  14 * just writes the result to stdout, removing headers and padding to
  15 * the right amount. It also writes some system data to stderr.
  16 */
  17
  18/*
  19 * Changes by tytso to allow root device specification
  20 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
  21 * Cross compiling fixes by Gertjan van Wingerde, July 1996
  22 * Rewritten by Martin Mares, April 1997
  23 * Substantially overhauled by H. Peter Anvin, April 2007
  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 <sys/mman.h>
  36#include <asm/boot.h>
  37
  38typedef unsigned char  u8;
  39typedef unsigned short u16;
  40typedef unsigned long  u32;
  41
  42#define DEFAULT_MAJOR_ROOT 0
  43#define DEFAULT_MINOR_ROOT 0
  44
  45/* Minimal number of setup sectors */
  46#define SETUP_SECT_MIN 5
  47#define SETUP_SECT_MAX 64
  48
  49/* This must be large enough to hold the entire setup */
  50u8 buf[SETUP_SECT_MAX*512];
  51int is_big_kernel;
  52
  53/*----------------------------------------------------------------------*/
  54
  55static const u32 crctab32[] = {
  56        0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
  57        0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
  58        0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
  59        0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
  60        0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,
  61        0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
  62        0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,
  63        0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
  64        0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
  65        0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,
  66        0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
  67        0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
  68        0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,
  69        0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,
  70        0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
  71        0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
  72        0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,
  73        0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
  74        0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,
  75        0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
  76        0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
  77        0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,
  78        0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,
  79        0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
  80        0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
  81        0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,
  82        0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
  83        0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
  84        0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,
  85        0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
  86        0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,
  87        0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
  88        0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
  89        0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,
  90        0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,
  91        0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
  92        0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,
  93        0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,
  94        0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
  95        0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
  96        0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,
  97        0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
  98        0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,
  99        0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
 100        0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
 101        0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
 102        0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,
 103        0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
 104        0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,
 105        0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,
 106        0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
 107        0x2d02ef8d
 108};
 109
 110static u32 partial_crc32_one(u8 c, u32 crc)
 111{
 112        return crctab32[(crc ^ c) & 0xff] ^ (crc >> 8);
 113}
 114
 115static u32 partial_crc32(const u8 *s, int len, u32 crc)
 116{
 117        while (len--)
 118                crc = partial_crc32_one(*s++, crc);
 119        return crc;
 120}
 121
 122static void die(const char * str, ...)
 123{
 124        va_list args;
 125        va_start(args, str);
 126        vfprintf(stderr, str, args);
 127        fputc('\n', stderr);
 128        exit(1);
 129}
 130
 131static void usage(void)
 132{
 133        die("Usage: build setup system [rootdev] [> image]");
 134}
 135
 136int main(int argc, char ** argv)
 137{
 138        unsigned int i, sz, setup_sectors;
 139        int c;
 140        u32 sys_size;
 141        u8 major_root, minor_root;
 142        struct stat sb;
 143        FILE *file;
 144        int fd;
 145        void *kernel;
 146        u32 crc = 0xffffffffUL;
 147
 148        if ((argc < 3) || (argc > 4))
 149                usage();
 150        if (argc > 3) {
 151                if (!strcmp(argv[3], "CURRENT")) {
 152                        if (stat("/", &sb)) {
 153                                perror("/");
 154                                die("Couldn't stat /");
 155                        }
 156                        major_root = major(sb.st_dev);
 157                        minor_root = minor(sb.st_dev);
 158                } else if (strcmp(argv[3], "FLOPPY")) {
 159                        if (stat(argv[3], &sb)) {
 160                                perror(argv[3]);
 161                                die("Couldn't stat root device.");
 162                        }
 163                        major_root = major(sb.st_rdev);
 164                        minor_root = minor(sb.st_rdev);
 165                } else {
 166                        major_root = 0;
 167                        minor_root = 0;
 168                }
 169        } else {
 170                major_root = DEFAULT_MAJOR_ROOT;
 171                minor_root = DEFAULT_MINOR_ROOT;
 172        }
 173        fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
 174
 175        /* Copy the setup code */
 176        file = fopen(argv[1], "r");
 177        if (!file)
 178                die("Unable to open `%s': %m", argv[1]);
 179        c = fread(buf, 1, sizeof(buf), file);
 180        if (ferror(file))
 181                die("read-error on `setup'");
 182        if (c < 1024)
 183                die("The setup must be at least 1024 bytes");
 184        if (buf[510] != 0x55 || buf[511] != 0xaa)
 185                die("Boot block hasn't got boot flag (0xAA55)");
 186        fclose(file);
 187
 188        /* Pad unused space with zeros */
 189        setup_sectors = (c + 511) / 512;
 190        if (setup_sectors < SETUP_SECT_MIN)
 191                setup_sectors = SETUP_SECT_MIN;
 192        i = setup_sectors*512;
 193        memset(buf+c, 0, i-c);
 194
 195        /* Set the default root device */
 196        buf[508] = minor_root;
 197        buf[509] = major_root;
 198
 199        fprintf(stderr, "Setup is %d bytes (padded to %d bytes).\n", c, i);
 200
 201        /* Open and stat the kernel file */
 202        fd = open(argv[2], O_RDONLY);
 203        if (fd < 0)
 204                die("Unable to open `%s': %m", argv[2]);
 205        if (fstat(fd, &sb))
 206                die("Unable to stat `%s': %m", argv[2]);
 207        sz = sb.st_size;
 208        fprintf (stderr, "System is %d kB\n", (sz+1023)/1024);
 209        kernel = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
 210        if (kernel == MAP_FAILED)
 211                die("Unable to mmap '%s': %m", argv[2]);
 212        /* Number of 16-byte paragraphs, including space for a 4-byte CRC */
 213        sys_size = (sz + 15 + 4) / 16;
 214
 215        /* Patch the setup code with the appropriate size parameters */
 216        buf[0x1f1] = setup_sectors-1;
 217        buf[0x1f4] = sys_size;
 218        buf[0x1f5] = sys_size >> 8;
 219        buf[0x1f6] = sys_size >> 16;
 220        buf[0x1f7] = sys_size >> 24;
 221
 222        crc = partial_crc32(buf, i, crc);
 223        if (fwrite(buf, 1, i, stdout) != i)
 224                die("Writing setup failed");
 225
 226        /* Copy the kernel code */
 227        crc = partial_crc32(kernel, sz, crc);
 228        if (fwrite(kernel, 1, sz, stdout) != sz)
 229                die("Writing kernel failed");
 230
 231        /* Add padding leaving 4 bytes for the checksum */
 232        while (sz++ < (sys_size*16) - 4) {
 233                crc = partial_crc32_one('\0', crc);
 234                if (fwrite("\0", 1, 1, stdout) != 1)
 235                        die("Writing padding failed");
 236        }
 237
 238        /* Write the CRC */
 239        fprintf(stderr, "CRC %lx\n", crc);
 240        if (fwrite(&crc, 1, 4, stdout) != 4)
 241                die("Writing CRC failed");
 242
 243        close(fd);
 244
 245        /* Everything is OK */
 246        return 0;
 247}
 248
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