arch/x86/boot/tools/build.c

   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
  38 typedef unsigned char  u8;
  39 typedef unsigned short u16;
  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 */
  46 #define SETUP_SECT_MIN 5
  47 #define SETUP_SECT_MAX 64
  48
  49 /* This must be large enough to hold the entire setup */
  50 u8 buf[SETUP_SECT_MAX*512];
  51 int is_big_kernel;
  52
  53 /*----------------------------------------------------------------------*/
  54
  55 static 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
 110 static u32 partial_crc32_one(u8 c, u32 crc)
 111 {
 112         return crctab32[(crc ^ c) & 0xff] ^ (crc >> 8);
 113 }
 114
 115 static 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
 122 static 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
 131 static void usage(void)
 132 {
 133         die("Usage: build setup system [> image]");
 134 }
 135
 136 int main(int argc, char ** argv)
 137 {
 138         unsigned int i, sz, setup_sectors;
 139         int c;
 140         u32 sys_size;
 141         struct stat sb;
 142         FILE *file;
 143         int fd;
 144         void *kernel;
 145         u32 crc = 0xffffffffUL;
 146
 147         if (argc != 3)
 148                 usage();
 149
 150         /* Copy the setup code */
 151         file = fopen(argv[1], "r");
 152         if (!file)
 153                 die("Unable to open `%s': %m", argv[1]);
 154         c = fread(buf, 1, sizeof(buf), file);
 155         if (ferror(file))
 156                 die("read-error on `setup'");
 157         if (c < 1024)
 158                 die("The setup must be at least 1024 bytes");
 159         if (buf[510] != 0x55 || buf[511] != 0xaa)
 160                 die("Boot block hasn't got boot flag (0xAA55)");
 161         fclose(file);
 162
 163         /* Pad unused space with zeros */
 164         setup_sectors = (c + 511) / 512;
 165         if (setup_sectors < SETUP_SECT_MIN)
 166                 setup_sectors = SETUP_SECT_MIN;
 167         i = setup_sectors*512;
 168         memset(buf+c, 0, i-c);
 169
 170         /* Set the default root device */
 171         buf[508] = DEFAULT_MINOR_ROOT;
 172         buf[509] = DEFAULT_MAJOR_ROOT;
 173
 174         fprintf(stderr, "Setup is %d bytes (padded to %d bytes).\n", c, i);
 175
 176         /* Open and stat the kernel file */
 177         fd = open(argv[2], O_RDONLY);
 178         if (fd < 0)
 179                 die("Unable to open `%s': %m", argv[2]);
 180         if (fstat(fd, &sb))
 181                 die("Unable to stat `%s': %m", argv[2]);
 182         sz = sb.st_size;
 183         fprintf (stderr, "System is %d kB\n", (sz+1023)/1024);
 184         kernel = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
 185         if (kernel == MAP_FAILED)
 186                 die("Unable to mmap '%s': %m", argv[2]);
 187         /* Number of 16-byte paragraphs, including space for a 4-byte CRC */
 188         sys_size = (sz + 15 + 4) / 16;
 189
 190         /* Patch the setup code with the appropriate size parameters */
 191         buf[0x1f1] = setup_sectors-1;
 192         buf[0x1f4] = sys_size;
 193         buf[0x1f5] = sys_size >> 8;
 194         buf[0x1f6] = sys_size >> 16;
 195         buf[0x1f7] = sys_size >> 24;
 196
 197         crc = partial_crc32(buf, i, crc);
 198         if (fwrite(buf, 1, i, stdout) != i)
 199                 die("Writing setup failed");
 200
 201         /* Copy the kernel code */
 202         crc = partial_crc32(kernel, sz, crc);
 203         if (fwrite(kernel, 1, sz, stdout) != sz)
 204                 die("Writing kernel failed");
 205
 206         /* Add padding leaving 4 bytes for the checksum */
 207         while (sz++ < (sys_size*16) - 4) {
 208                 crc = partial_crc32_one('\0', crc);
 209                 if (fwrite("\0", 1, 1, stdout) != 1)
 210                         die("Writing padding failed");
 211         }
 212
 213         /* Write the CRC */
 214         fprintf(stderr, "CRC %lx\n", crc);
 215         if (fwrite(&crc, 1, 4, stdout) != 4)
 216                 die("Writing CRC failed");
 217
 218         close(fd);
 219
 220         /* Everything is OK */
 221         return 0;
 222 }