rdf2bin.c

开源的nasm编译器源码,研究编译器原理很有帮且

/* rdf2bin: convert an RDOFF object file to flat binary */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "rdfload.h"
#include "rdoff.h"
#include "nasmlib.h"

long origin = 0;
int align = 16;

char *getfilename(char * pathname)
{
    char * lastslash = pathname - 1;
    char * i = pathname;

    while ( *i ) {
	if (*i == '/') lastslash = i;
	i++;
    }
    return lastslash + 1;
}

int main(int argc, char **argv)
{
    rdfmodule 	* m;
    int 	tmp;
    FILE 	*of;
    char 	* padding;
    int 	codepad, datapad, bsspad=0;

    if (argc < 2) {
	puts("Usage: rdf2bin [-o relocation-origin] [-p segment-alignment] "
	     "input-file  output-file");
	puts("       rdf2com [-p segment-alignment] input-file output-file");
	return 1;
    }

    if (! nasm_stricmp(getfilename(*argv),"rdf2com")) {
	origin = 0x100;
    }
    argv++, argc--;

    while (argc > 2) {
	if (! strcmp(*argv,"-o")) {
	    argv++, argc--;
	    origin = readnum(*argv, &tmp);
	    if (tmp) {
		fprintf(stderr,"rdf2bin: invalid parameter: %s\n",*argv);
		return 1;
	    }
	} else if (! strcmp(*argv,"-p")) {
	    argv++, argc--;
	    align = readnum(*argv, &tmp);
	    if (tmp) {
		fprintf(stderr,"rdf2bin: invalid parameter: %s\n",*argv);
		return 1;
	    }
	} else if (! strcmp(*argv,"-b")) {
	    argv++, argc--;
	    bsspad = readnum(*argv, &tmp);
	    if (tmp) {
		fprintf(stderr,"rdf2bin: invalid parameter: %s\n",*argv);
		return 1;
	    }    
	} else 
	    break;

	argv++, argc--;
    }
    if (argc < 2) {
	puts("rdf2bin: required parameter missing");
	return -1;
    }
    m = rdfload(*argv);

    if (! m) {
	rdfperror("rdf2bin",*argv);
	return 1;
    }
    printf("relocating %s: origin=%lx, align=%d\n",*argv,origin,align);

    m->textrel = origin;
    m->datarel = origin + m->f.seg[0].length;
    if (m->datarel % align != 0) {
	codepad = align - (m->datarel % align);
	m->datarel += codepad;
    }
    else
	codepad = 0;

    m->bssrel = m->datarel + m->f.seg[1].length;
    if (m->bssrel % align != 0) {
	datapad = align - (m->bssrel % align);
	m->bssrel += datapad;
    }
    else
	datapad = 0;

    printf("code: %08lx\ndata: %08lx\nbss:  %08lx\n",
	   m->textrel, m->datarel, m->bssrel);

    rdf_relocate(m);

    argv++;

    of = fopen(*argv,"wb");
    if (!of) {
	fprintf(stderr,"rdf2bin: could not open output file %s\n",*argv);
	return 1;
    }

    padding = malloc(align);
    if (!padding) {
	fprintf(stderr,"rdf2bin: out of memory\n");
	return 1;
    }

    if (fwrite(m->t,1,m->f.seg[0].length,of) != m->f.seg[0].length ||
	fwrite(padding,1,codepad,of) != codepad ||
	fwrite(m->d,1,m->f.seg[1].length,of) != m->f.seg[1].length) 
    {
	fprintf(stderr,"rdf2bin: error writing to %s\n", *argv);
	return 1;
    }
    
    if (bsspad) {
    	void *p = calloc(bsspad-=(m->bssrel - origin),1);
	fwrite(p,1,bsspad,of);
    }

    fclose(of);
    return 0;
}