root/tools/build.c.orig

/* */

/*
 *  linux/tools/build.c
 *
 *  (C) 1991  Linus Torvalds
 */

/*
 * This file builds a disk-image from three different files:
 *
 * - bootsect: max 510 bytes of 8086 machine code, loads the rest
 * - setup: max 4 sectors of 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.
 */

#include <stdio.h>      /* fprintf */
#include <stdlib.h>     /* contains exit */
#include <sys/types.h>  /* unistd.h needs this */
#include <unistd.h>     /* contains read/write */
#include <fcntl.h>

#define MINIX_HEADER 32
#define GCC_HEADER 1024

/* max nr of sectors of setup: don't change unless you also change
 * bootsect etc */
#define SETUP_SECTS 4

#define STRINGIFY(x) #x

void die(char * str)
{
        fprintf(stderr,"%s\n",str);
        exit(1);
}

void usage(void)
{
        die("Usage: build bootsect setup system [> image]");
}

int main(int argc, char ** argv)
{
        int i,c,id;
        char buf[1024];

        if (argc != 4)
                usage();
        for (i=0;i<sizeof buf; i++) buf[i]=0;
        if ((id=open(argv[1],O_RDONLY,0))<0)
                die("Unable to open 'boot'");
        if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
                die("Unable to read header of 'boot'");
        if (((long *) buf)[0]!=0x04100301)
                die("Non-Minix header of 'boot'");
        if (((long *) buf)[1]!=MINIX_HEADER)
                die("Non-Minix header of 'boot'");
        if (((long *) buf)[3]!=0)
                die("Illegal data segment in 'boot'");
        if (((long *) buf)[4]!=0)
                die("Illegal bss in 'boot'");
        if (((long *) buf)[5] != 0)
                die("Non-Minix header of 'boot'");
        if (((long *) buf)[7] != 0)
                die("Illegal symbol table in 'boot'");
        i=read(id,buf,sizeof buf);
        fprintf(stderr,"Boot sector %d bytes.\n",i);
        if (i != 512)
                die("Boot block must be exactly 512 bytes");
        if ((*(unsigned short *)(buf+510)) != 0xAA55)
                die("Boot block hasn't got boot flag (0xAA55)");
        i=write(1,buf,512);
        if (i!=512)
                die("Write call failed");
        close (id);
        
        if ((id=open(argv[2],O_RDONLY,0))<0)
                die("Unable to open 'setup'");
        if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
                die("Unable to read header of 'setup'");
        if (((long *) buf)[0]!=0x04100301)
                die("Non-Minix header of 'setup'");
        if (((long *) buf)[1]!=MINIX_HEADER)
                die("Non-Minix header of 'setup'");
        if (((long *) buf)[3]!=0)
                die("Illegal data segment in 'setup'");
        if (((long *) buf)[4]!=0)
                die("Illegal bss in 'setup'");
        if (((long *) buf)[5] != 0)
                die("Non-Minix header of 'setup'");
        if (((long *) buf)[7] != 0)
                die("Illegal symbol table in 'setup'");
        for (i=0 ; (c=read(id,buf,sizeof buf))>0 ; i+=c )
                if (write(1,buf,c)!=c)
                        die("Write call failed");
        close (id);
        if (i > SETUP_SECTS*512)
                die("Setup exceeds " STRINGIFY(SETUP_SECTS)
                        " sectors - rewrite build/boot/setup");
        fprintf(stderr,"Setup is %d bytes.\n",i);
        for (c=0 ; c<sizeof(buf) ; c++)
                buf[c] = '\0';
        while (i<SETUP_SECTS*512) {
                c = SETUP_SECTS*512-i;
                if (c > sizeof(buf))
                        c = sizeof(buf);
                if (write(1,buf,c) != c)
                        die("Write call failed");
                i += c;
        }
        
        if ((id=open(argv[3],O_RDONLY,0))<0)
                die("Unable to open 'system'");
        if (read(id,buf,GCC_HEADER) != GCC_HEADER)
                die("Unable to read header of 'system'");
        if (((long *) buf)[5] != 0)
                die("Non-GCC header of 'system'");
        for (i=0 ; (c=read(id,buf,sizeof buf))>0 ; i+=c )
                if (write(1,buf,c)!=c)
                        die("Write call failed");
        close(id);
        fprintf(stderr,"System is %d bytes.\n",i);
        return(0);
}

/* */