/* *  $Id: build.c,v 1.5 1997/05/19 12:29:58 mj Exp $ * *  Copyright (C) 1991, 1992  Linus Torvalds *  Copyright (C) 1997 Martin Mares *//* * This file builds a disk-image from three different files: * * - bootsect: exactly 512 bytes of 8086 machine code, loads the rest * - setup: 8086 machine code, sets up system parm * - system: 80386 code for actual system * * It does some checking that all files are of the correct type, and * just writes the result to stdout, removing headers and padding to * the right amount. It also writes some system data to stderr. *//* * Changes by tytso to allow root device specification * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 * Cross compiling fixes by Gertjan van Wingerde, July 1996 * Rewritten by Martin Mares, April 1997 */#include <stdio.h>#include <string.h>#include <stdlib.h>#include <stdarg.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/sysmacros.h>#include <unistd.h>#include <fcntl.h>#include <asm/boot.h>typedef unsigned char byte;typedef unsigned short word;typedef unsigned long u32;#define DEFAULT_MAJOR_ROOT 0#define DEFAULT_MINOR_ROOT 0/* Minimal number of setup sectors (see also bootsect.S) */#define SETUP_SECTS 4byte buf[1024];int fd;int is_big_kernel;void die(const char * str, ...){	va_list args;	va_start(args, str);	vfprintf(stderr, str, args);	fputc('\n', stderr);	exit(1);}void file_open(const char *name){	if ((fd = open(name, O_RDONLY, 0)) < 0)		die("Unable to open `%s': %m", name);}void usage(void){	die("Usage: build [-b] bootsect setup system [rootdev] [> image]");}int main(int argc, char ** argv){	unsigned int i, c, sz, setup_sectors;	u32 sys_size;	byte major_root, minor_root;	struct stat sb;	if (argc > 2 && !strcmp(argv[1], "-b"))	  {	    is_big_kernel = 1;	    argc--, argv++;	  }	if ((argc < 4) || (argc > 5))		usage();	if (argc > 4) {		if (!strcmp(argv[4], "CURRENT")) {			if (stat("/", &sb)) {				perror("/");				die("Couldn't stat /");			}			major_root = major(sb.st_dev);			minor_root = minor(sb.st_dev);		} else if (strcmp(argv[4], "FLOPPY")) {			if (stat(argv[4], &sb)) {				perror(argv[4]);				die("Couldn't stat root device.");			}			major_root = major(sb.st_rdev);			minor_root = minor(sb.st_rdev);		} else {			major_root = 0;			minor_root = 0;		}	} else {		major_root = DEFAULT_MAJOR_ROOT;		minor_root = DEFAULT_MINOR_ROOT;	}	fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);	file_open(argv[1]);	i = read(fd, buf, sizeof(buf));	fprintf(stderr,"Boot sector %d bytes.\n",i);	if (i != 512)		die("Boot block must be exactly 512 bytes");	if (buf[510] != 0x55 || buf[511] != 0xaa)		die("Boot block hasn't got boot flag (0xAA55)");	buf[508] = minor_root;	buf[509] = major_root;	if (write(1, buf, 512) != 512)		die("Write call failed");	close (fd);	file_open(argv[2]);				    /* Copy the setup code */	for (i=0 ; (c=read(fd, buf, sizeof(buf)))>0 ; i+=c )		if (write(1, buf, c) != c)			die("Write call failed");	if (c != 0)		die("read-error on `setup'");	close (fd);	setup_sectors = (i + 511) / 512;	/* Pad unused space with zeros */	/* for compatibility with ancient versions of LILO. */	if (setup_sectors < SETUP_SECTS)		setup_sectors = SETUP_SECTS;	fprintf(stderr, "Setup is %d bytes.\n", i);	memset(buf, 0, sizeof(buf));	while (i < setup_sectors * 512) {		c = setup_sectors * 512 - i;		if (c > sizeof(buf))			c = sizeof(buf);		if (write(1, buf, c) != c)			die("Write call failed");		i += c;	}	file_open(argv[3]);	if (fstat (fd, &sb))		die("Unable to stat `%s': %m", argv[3]);	sz = sb.st_size;	fprintf (stderr, "System is %d kB\n", sz/1024);	sys_size = (sz + 15) / 16;	/* 0x28000*16 = 2.5 MB, conservative estimate for the current maximum */	if (sys_size > (is_big_kernel ? 0x28000 : DEF_SYSSIZE))		die("System is too big. Try using %smodules.",			is_big_kernel ? "" : "bzImage or ");	if (sys_size > 0xefff)		fprintf(stderr,"warning: kernel is too big for standalone boot "		    "from floppy\n");	while (sz > 0) {		int l, n;		l = (sz > sizeof(buf)) ? sizeof(buf) : sz;		if ((n=read(fd, buf, l)) != l) {			if (n < 0)				die("Error reading %s: %m", argv[3]);			else				die("%s: Unexpected EOF", argv[3]);		}		if (write(1, buf, l) != l)			die("Write failed");		sz -= l;	}	close(fd);	if (lseek(1, 497, SEEK_SET) != 497)		    /* Write sizes to the bootsector */		die("Output: seek failed");	buf[0] = setup_sectors;	if (write(1, buf, 1) != 1)		die("Write of setup sector count failed");	if (lseek(1, 500, SEEK_SET) != 500)		die("Output: seek failed");	buf[0] = (sys_size & 0xff);	buf[1] = ((sys_size >> 8) & 0xff);	if (write(1, buf, 2) != 2)		die("Write of image length failed");	return 0;					    /* Everything is OK */}