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: exactly 512 bytes of 8086 machine code, loads the rest 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 */ 24 25#include <stdio.h> 26#include <string.h> 27#include <stdlib.h> 28#include <stdarg.h> 29#include <sys/types.h> 30#include <sys/stat.h> 31#include <sys/sysmacros.h> 32#include <unistd.h> 33#include <fcntl.h> 34#include <asm/boot.h> 35 36#define DEFAULT_MAJOR_ROOT 0 37#define DEFAULT_MINOR_ROOT 0 38 39/* Minimal number of setup sectors (see also bootsect.S) */ 40#define SETUP_SECTS 4 41 42uint8_t buf[1024]; 43int fd; 44int is_big_kernel; 45 46__attribute__((noreturn)) 47void die(const char *str, ...) 48{ 49 va_list args; 50 va_start(args, str); 51 vfprintf(stderr, str, args); 52 fputc('\n', stderr); 53 exit(1); 54} 55 56void file_open(const char *name) 57{ 58 fd = open(name, O_RDONLY, 0); 59 if (fd < 0) 60 die("Unable to open `%s': %m", name); 61} 62 63__attribute__((noreturn)) 64void usage(void) 65{ 66 die("Usage: build [-b] bootsect setup system [rootdev] [> image]"); 67} 68 69int main(int argc, char **argv) 70{ 71 unsigned int i, c, sz, setup_sectors; 72 uint32_t sys_size; 73 uint8_t major_root, minor_root; 74 struct stat sb; 75 76 if (argc > 2 && !strcmp(argv[1], "-b")) { 77 is_big_kernel = 1; 78 argc--, argv++; 79 } 80 if ((argc < 4) || (argc > 5)) 81 usage(); 82 if (argc > 4) { 83 if (!strcmp(argv[4], "CURRENT")) { 84 if (stat("/", &sb)) { 85 perror("/"); 86 die("Couldn't stat /"); 87 } 88 major_root = major(sb.st_dev); 89 minor_root = minor(sb.st_dev); 90 } else if (strcmp(argv[4], "FLOPPY")) { 91 if (stat(argv[4], &sb)) { 92 perror(argv[4]); 93 die("Couldn't stat root device."); 94 } 95 major_root = major(sb.st_rdev); 96 minor_root = minor(sb.st_rdev); 97 } else { 98 major_root = 0; 99 minor_root = 0; 100 } 101 } else { 102 major_root = DEFAULT_MAJOR_ROOT; 103 minor_root = DEFAULT_MINOR_ROOT; 104 } 105 fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root); 106 107 file_open(argv[1]); 108 i = read(fd, buf, sizeof(buf)); 109 fprintf(stderr, "Boot sector %d bytes.\n", i); 110 if (i != 512) 111 die("Boot block must be exactly 512 bytes"); 112 if (buf[510] != 0x55 || buf[511] != 0xaa) 113 die("Boot block hasn't got boot flag (0xAA55)"); 114 buf[508] = minor_root; 115 buf[509] = major_root; 116 if (write(1, buf, 512) != 512) 117 die("Write call failed"); 118 close(fd); 119 120 /* Copy the setup code */ 121 file_open(argv[2]); 122 for (i = 0; (c = read(fd, buf, sizeof(buf))) > 0; i += c) 123 if (write(1, buf, c) != c) 124 die("Write call failed"); 125 if (c != 0) 126 die("read-error on `setup'"); 127 close(fd); 128 129 /* Pad unused space with zeros */ 130 setup_sectors = (i + 511) / 512; 131 /* for compatibility with ancient versions of LILO. */ 132 if (setup_sectors < SETUP_SECTS) 133 setup_sectors = SETUP_SECTS; 134 fprintf(stderr, "Setup is %d bytes.\n", i); 135 memset(buf, 0, sizeof(buf)); 136 while (i < setup_sectors * 512) { 137 c = setup_sectors * 512 - i; 138 if (c > sizeof(buf)) 139 c = sizeof(buf); 140 if (write(1, buf, c) != c) 141 die("Write call failed"); 142 i += c; 143 } 144 145 file_open(argv[3]); 146 if (fstat(fd, &sb)) 147 die("Unable to stat `%s': %m", argv[3]); 148 sz = sb.st_size; 149 fprintf(stderr, "System is %d kB\n", sz / 1024); 150 sys_size = (sz + 15) / 16; 151 /* 0x28000*16 = 2.5 MB, conservative estimate for the current maximum */ 152 if (sys_size > (is_big_kernel ? 0x28000 : DEF_SYSSIZE)) 153 die("System is too big. Try using %smodules.", 154 is_big_kernel ? "" : "bzImage or "); 155 if (sys_size > 0xffff) 156 fprintf(stderr, 157 "warning: kernel is too big for standalone boot " 158 "from floppy\n"); 159 while (sz > 0) { 160 int l, n; 161 162 l = (sz > sizeof(buf)) ? sizeof(buf) : sz; 163 n = read(fd, buf, l); 164 if (n != 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 /* Write sizes to the bootsector */ 177 if (lseek(1, 497, SEEK_SET) != 497) 178 die("Output: seek failed"); 179 buf[0] = setup_sectors; 180 if (write(1, buf, 1) != 1) 181 die("Write of setup sector count failed"); 182 if (lseek(1, 500, SEEK_SET) != 500) 183 die("Output: seek failed"); 184 buf[0] = (sys_size & 0xff); 185 buf[1] = ((sys_size >> 8) & 0xff); 186 if (write(1, buf, 2) != 2) 187 die("Write of image length failed"); 188 189 return 0; 190} 191