1/* 2 * Copyright (C) 1991, 1992 Linus Torvalds 3 * Copyright (C) 1997 Martin Mares 4 */ 5 6/* 7 * This file builds a disk-image from three different files: 8 * 9 * - bootsect: compatibility mbr which prints an error message if 10 * someone tries to boot the kernel directly. 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 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 22 * Cross compiling fixes by Gertjan van Wingerde, July 1996 23 * Rewritten by Martin Mares, April 1997 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 <asm/boot.h> 36 37typedef unsigned char byte; 38typedef unsigned short word; 39typedef unsigned long u32; 40 41#define DEFAULT_MAJOR_ROOT 0 42#define DEFAULT_MINOR_ROOT 0 43 44/* Minimal number of setup sectors (see also bootsect.S) */ 45#define SETUP_SECTS 4 46 47byte buf[1024]; 48int fd; 49int is_big_kernel; 50 51void die(const char * str, ...) 52{ 53 va_list args; 54 va_start(args, str); 55 vfprintf(stderr, str, args); 56 fputc('\n', stderr); 57 exit(1); 58} 59 60void file_open(const char *name) 61{ 62 if ((fd = open(name, O_RDONLY, 0)) < 0) 63 die("Unable to open `%s': %m", name); 64} 65 66void usage(void) 67{ 68 die("Usage: build [-b] bootsect setup system [rootdev] [> image]"); 69} 70 71int main(int argc, char ** argv) 72{ 73 unsigned int i, c, sz, setup_sectors; 74 u32 sys_size; 75 byte major_root, minor_root; 76 struct stat sb; 77 78 if (argc > 2 && !strcmp(argv[1], "-b")) 79 { 80 is_big_kernel = 1; 81 argc--, argv++; 82 } 83 if ((argc < 4) || (argc > 5)) 84 usage(); 85 if (argc > 4) { 86 if (!strcmp(argv[4], "CURRENT")) { 87 if (stat("/", &sb)) { 88 perror("/"); 89 die("Couldn't stat /"); 90 } 91 major_root = major(sb.st_dev); 92 minor_root = minor(sb.st_dev); 93 } else if (strcmp(argv[4], "FLOPPY")) { 94 if (stat(argv[4], &sb)) { 95 perror(argv[4]); 96 die("Couldn't stat root device."); 97 } 98 major_root = major(sb.st_rdev); 99 minor_root = minor(sb.st_rdev); 100 } else { 101 major_root = 0; 102 minor_root = 0; 103 } 104 } else { 105 major_root = DEFAULT_MAJOR_ROOT; 106 minor_root = DEFAULT_MINOR_ROOT; 107 } 108 fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root); 109 110 file_open(argv[1]); 111 i = read(fd, buf, sizeof(buf)); 112 fprintf(stderr,"Boot sector %d bytes.\n",i); 113 if (i != 512) 114 die("Boot block must be exactly 512 bytes"); 115 if (buf[510] != 0x55 || buf[511] != 0xaa) 116 die("Boot block hasn't got boot flag (0xAA55)"); 117 buf[508] = minor_root; 118 buf[509] = major_root; 119 if (write(1, buf, 512) != 512) 120 die("Write call failed"); 121 close (fd); 122 123 file_open(argv[2]); /* Copy the setup code */ 124 for (i=0 ; (c=read(fd, buf, sizeof(buf)))>0 ; i+=c ) 125 if (write(1, buf, c) != c) 126 die("Write call failed"); 127 if (c != 0) 128 die("read-error on `setup'"); 129 close (fd); 130 131 setup_sectors = (i + 511) / 512; /* Pad unused space with zeros */ 132 /* for compatibility with ancient versions of LILO. */ 133 if (setup_sectors < SETUP_SECTS) 134 setup_sectors = SETUP_SECTS; 135 fprintf(stderr, "Setup is %d bytes.\n", i); 136 memset(buf, 0, sizeof(buf)); 137 while (i < setup_sectors * 512) { 138 c = setup_sectors * 512 - i; 139 if (c > sizeof(buf)) 140 c = sizeof(buf); 141 if (write(1, buf, c) != c) 142 die("Write call failed"); 143 i += c; 144 } 145 146 file_open(argv[3]); 147 if (fstat (fd, &sb)) 148 die("Unable to stat `%s': %m", argv[3]); 149 sz = sb.st_size; 150 fprintf (stderr, "System is %d kB\n", sz/1024); 151 sys_size = (sz + 15) / 16; 152 if (!is_big_kernel && sys_size > DEF_SYSSIZE) 153 die("System is too big. Try using bzImage or modules."); 154 while (sz > 0) { 155 int l, n; 156 157 l = (sz > sizeof(buf)) ? sizeof(buf) : sz; 158 if ((n=read(fd, buf, l)) != l) { 159 if (n < 0) 160 die("Error reading %s: %m", argv[3]); 161 else 162 die("%s: Unexpected EOF", argv[3]); 163 } 164 if (write(1, buf, l) != l) 165 die("Write failed"); 166 sz -= l; 167 } 168 close(fd); 169 170 if (lseek(1, 497, SEEK_SET) != 497) /* Write sizes to the bootsector */ 171 die("Output: seek failed"); 172 buf[0] = setup_sectors; 173 if (write(1, buf, 1) != 1) 174 die("Write of setup sector count failed"); 175 if (lseek(1, 500, SEEK_SET) != 500) 176 die("Output: seek failed"); 177 buf[0] = (sys_size & 0xff); 178 buf[1] = ((sys_size >> 8) & 0xff); 179 buf[2] = ((sys_size >> 16) & 0xff); 180 buf[3] = ((sys_size >> 24) & 0xff); 181 if (write(1, buf, 4) != 4) 182 die("Write of image length failed"); 183 184 return 0; /* Everything is OK */ 185} 186