root/arch/i386/boot/tools/build.c

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DEFINITIONS

This source file includes following definitions.
  1. intel_long
  2. intel_short
  3. die
  4. usage
  5. main

   1 /*
   2  *  linux/tools/build.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6 
   7 /*
   8  * This file builds a disk-image from three different files:
   9  *
  10  * - bootsect: exactly 512 bytes of 8086 machine code, loads the rest
  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  */
  22 
  23 #include <stdio.h>      /* fprintf */
  24 #include <string.h>
  25 #include <stdlib.h>     /* contains exit */
  26 #include <sys/types.h>  /* unistd.h needs this */
  27 #include <sys/stat.h>
  28 #include <sys/sysmacros.h>
  29 #include <unistd.h>     /* contains read/write */
  30 #include <fcntl.h>
  31 #include <linux/a.out.h>
  32 #include <linux/config.h>
  33 #include <errno.h>
  34 
  35 #define MINIX_HEADER 32
  36 
  37 #define N_MAGIC_OFFSET 1024
  38 #ifndef __BFD__
  39 static int GCC_HEADER = sizeof(struct exec);
  40 #endif
  41 
  42 #define SYS_SIZE DEF_SYSSIZE
  43 
  44 #define DEFAULT_MAJOR_ROOT 0
  45 #define DEFAULT_MINOR_ROOT 0
  46 
  47 /* max nr of sectors of setup: don't change unless you also change
  48  * bootsect etc */
  49 #define SETUP_SECTS 4
  50 
  51 #define STRINGIFY(x) #x
  52 
  53 typedef union {
  54         long l;
  55         short s[2];
  56         char b[4];
  57 } conv;
  58 
  59 long intel_long(long l)
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  60 {
  61         conv t;
  62 
  63         t.b[0] = l & 0xff; l >>= 8;
  64         t.b[1] = l & 0xff; l >>= 8;
  65         t.b[2] = l & 0xff; l >>= 8;
  66         t.b[3] = l & 0xff; l >>= 8;
  67         return t.l;
  68 }
  69 
  70 short intel_short(short l)
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  71 {
  72         conv t;
  73 
  74         t.b[0] = l & 0xff; l >>= 8;
  75         t.b[1] = l & 0xff; l >>= 8;
  76         return t.s[0];
  77 }
  78 
  79 void die(const char * str)
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  80 {
  81         fprintf(stderr,"%s\n",str);
  82         exit(1);
  83 }
  84 
  85 void usage(void)
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  86 {
  87         die("Usage: build bootsect setup system [rootdev] [> image]");
  88 }
  89 
  90 int main(int argc, char ** argv)
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  91 {
  92         int i,c,id, sz;
  93         unsigned long sys_size;
  94         char buf[1024];
  95 #ifndef __BFD__
  96         struct exec *ex = (struct exec *)buf;
  97 #endif
  98         char major_root, minor_root;
  99         struct stat sb;
 100         unsigned char setup_sectors;
 101 
 102         if ((argc < 4) || (argc > 5))
 103                 usage();
 104         if (argc > 4) {
 105                 if (!strcmp(argv[4], "CURRENT")) {
 106                         if (stat("/", &sb)) {
 107                                 perror("/");
 108                                 die("Couldn't stat /");
 109                         }
 110                         major_root = major(sb.st_dev);
 111                         minor_root = minor(sb.st_dev);
 112                 } else if (strcmp(argv[4], "FLOPPY")) {
 113                         if (stat(argv[4], &sb)) {
 114                                 perror(argv[4]);
 115                                 die("Couldn't stat root device.");
 116                         }
 117                         major_root = major(sb.st_rdev);
 118                         minor_root = minor(sb.st_rdev);
 119                 } else {
 120                         major_root = 0;
 121                         minor_root = 0;
 122                 }
 123         } else {
 124                 major_root = DEFAULT_MAJOR_ROOT;
 125                 minor_root = DEFAULT_MINOR_ROOT;
 126         }
 127         fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
 128         for (i=0;i<sizeof buf; i++) buf[i]=0;
 129         if ((id=open(argv[1],O_RDONLY,0))<0)
 130                 die("Unable to open 'boot'");
 131         if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
 132                 die("Unable to read header of 'boot'");
 133         if (((long *) buf)[0]!=intel_long(0x04100301))
 134                 die("Non-Minix header of 'boot'");
 135         if (((long *) buf)[1]!=intel_long(MINIX_HEADER))
 136                 die("Non-Minix header of 'boot'");
 137         if (((long *) buf)[3] != 0)
 138                 die("Illegal data segment in 'boot'");
 139         if (((long *) buf)[4] != 0)
 140                 die("Illegal bss in 'boot'");
 141         if (((long *) buf)[5] != 0)
 142                 die("Non-Minix header of 'boot'");
 143         if (((long *) buf)[7] != 0)
 144                 die("Illegal symbol table in 'boot'");
 145         i=read(id,buf,sizeof buf);
 146         fprintf(stderr,"Boot sector %d bytes.\n",i);
 147         if (i != 512)
 148                 die("Boot block must be exactly 512 bytes");
 149         if ((*(unsigned short *)(buf+510)) != (unsigned short)intel_short(0xAA55))
 150                 die("Boot block hasn't got boot flag (0xAA55)");
 151         buf[508] = (char) minor_root;
 152         buf[509] = (char) major_root;   
 153         i=write(1,buf,512);
 154         if (i!=512)
 155                 die("Write call failed");
 156         close (id);
 157         
 158         if ((id=open(argv[2],O_RDONLY,0))<0)
 159                 die("Unable to open 'setup'");
 160         if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
 161                 die("Unable to read header of 'setup'");
 162         if (((long *) buf)[0]!=intel_long(0x04100301))
 163                 die("Non-Minix header of 'setup'");
 164         if (((long *) buf)[1]!=intel_long(MINIX_HEADER))
 165                 die("Non-Minix header of 'setup'");
 166         if (((long *) buf)[3] != 0)
 167                 die("Illegal data segment in 'setup'");
 168         if (((long *) buf)[4] != 0)
 169                 die("Illegal bss in 'setup'");
 170         if (((long *) buf)[5] != 0)
 171                 die("Non-Minix header of 'setup'");
 172         if (((long *) buf)[7] != 0)
 173                 die("Illegal symbol table in 'setup'");
 174         for (i=0 ; (c=read(id,buf,sizeof buf))>0 ; i+=c )
 175                 if (write(1,buf,c)!=c)
 176                         die("Write call failed");
 177         if (c != 0)
 178                 die("read-error on 'setup'");
 179         close (id);
 180         setup_sectors = (unsigned char)((i + 511) / 512);
 181         /* for compatibility with LILO */
 182         if (setup_sectors < SETUP_SECTS)
 183                 setup_sectors = SETUP_SECTS;
 184         fprintf(stderr,"Setup is %d bytes.\n",i);
 185         for (c=0 ; c<sizeof(buf) ; c++)
 186                 buf[c] = '\0';
 187         while (i < setup_sectors * 512) {
 188                 c = setup_sectors * 512 - i;
 189                 if (c > sizeof(buf))
 190                         c = sizeof(buf);
 191                 if (write(1,buf,c) != c)
 192                         die("Write call failed");
 193                 i += c;
 194         }
 195         
 196         if ((id=open(argv[3],O_RDONLY,0))<0)
 197                 die("Unable to open 'system'");
 198 #ifndef __BFD__
 199         if (read(id,buf,GCC_HEADER) != GCC_HEADER)
 200                 die("Unable to read header of 'system'");
 201         if (N_MAGIC(*ex) == ZMAGIC) {
 202                 GCC_HEADER = N_MAGIC_OFFSET;
 203                 lseek(id, GCC_HEADER, SEEK_SET);
 204         } else if (N_MAGIC(*ex) != QMAGIC)
 205                 die("Non-GCC header of 'system'");
 206         fprintf(stderr,"System is %d kB (%d kB code, %d kB data and %d kB bss)\n",
 207                 (ex->a_text+ex->a_data+ex->a_bss)/1024,
 208                 ex->a_text /1024,
 209                 ex->a_data /1024,
 210                 ex->a_bss  /1024);
 211         sz = N_SYMOFF(*ex) - GCC_HEADER + 4;
 212 #else
 213         if (fstat (id, &sb)) {
 214           perror ("fstat");
 215           die ("Unable to stat 'system'");
 216         }
 217         sz = sb.st_size;
 218         fprintf (stderr, "System is %d kB\n", sz/1024);
 219 #endif
 220         sys_size = (sz + 15) / 16;
 221         if (sys_size > SYS_SIZE)
 222                 die("System is too big");
 223         while (sz > 0) {
 224                 int l, n;
 225 
 226                 l = sz;
 227                 if (l > sizeof(buf))
 228                         l = sizeof(buf);
 229                 if ((n=read(id, buf, l)) != l) {
 230                         if (n == -1) 
 231                                 perror(argv[1]);
 232                         else
 233                                 fprintf(stderr, "Unexpected EOF\n");
 234                         die("Can't read 'system'");
 235                 }
 236                 if (write(1, buf, l) != l)
 237                         die("Write failed");
 238                 sz -= l;
 239         }
 240         close(id);
 241         if (lseek(1, 497, 0) == 497) {
 242                 if (write(1, &setup_sectors, 1) != 1)
 243                         die("Write of setup sectors failed");
 244         }
 245         if (lseek(1,500,0) == 500) {
 246                 buf[0] = (sys_size & 0xff);
 247                 buf[1] = ((sys_size >> 8) & 0xff);
 248                 if (write(1, buf, 2) != 2)
 249                         die("Write failed");
 250         }
 251         return(0);
 252 }

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