rizin/libr/bin/format/coff/coff.c

/* radare - LGPL - Copyright 2008-2015 pancake, inisider */

#include <r_util.h>

#include "coff.h"

bool r_coff_supported_arch (const ut8 *buf) {
	ut16 arch = *(ut16*)buf;
	switch (arch) {
	case COFF_FILE_MACHINE_AMD64:
	case COFF_FILE_MACHINE_I386:
	case COFF_FILE_MACHINE_H8300:
	case COFF_FILE_TI_COFF:
		return true;
	default:
		return false;
	}
}

int r_coff_is_stripped (struct r_bin_coff_obj *obj) {
	return !!(obj->hdr.f_flags & (COFF_FLAGS_TI_F_RELFLG | \
		COFF_FLAGS_TI_F_LNNO | COFF_FLAGS_TI_F_LSYMS));
}

const char *r_coff_symbol_name (struct r_bin_coff_obj *obj, void *ptr) {
// XXX: this must be fixed (fuzzy can make it crash)
#if 0
	union { char name[8]; struct { ut32 zero; ut32 offset; }; } *p = ptr;
	if (!ptr)
		return NULL;
	if (p->zero)
		return p->name;

	return (char *)obj->b->buf + obj->hdr.f_symptr + 
		obj->hdr.f_nsyms * sizeof (struct coff_symbol) + p->offset;
#else
	return NULL;
#endif
}

static int r_coff_rebase_sym (struct r_bin_coff_obj *obj, RBinAddr *addr, struct coff_symbol *sym) {
	if (sym->n_scnum<1 || sym->n_scnum > obj->hdr.f_nscns)
		return 0;
	addr->paddr = obj->scn_hdrs[sym->n_scnum - 1].s_scnptr + sym->n_value;
	return 1;
}

/* Try to get a valid entrypoint using the methods outlined in 
 * http://ftp.gnu.org/old-gnu/Manuals/ld-2.9.1/html_mono/ld.html#SEC24 */
RBinAddr *r_coff_get_entry(struct r_bin_coff_obj *obj) {
	RBinAddr *addr = R_NEW0 (RBinAddr);
	int i;
	if (!addr) return NULL;

	/* Simplest case, the header provides the entrypoint address */
	if (obj->hdr.f_opthdr) {
		addr->paddr = obj->opt_hdr.entry;
		return addr;
	}

	/* No help from the header eh? Use the address of the symbols '_start'
	 * or 'main' if present */
	if (obj->symbols)
	for (i = 0; i < obj->hdr.f_nsyms; i++) {
		if ((!strcmp (obj->symbols[i].n_name, "_start") || 
			!strcmp (obj->symbols[i].n_name, "start")) &&
			r_coff_rebase_sym (obj, addr, &obj->symbols[i]))
			return addr;
	}

	if (obj->symbols)
	for (i = 0; i < obj->hdr.f_nsyms; i++) {
		if ((!strcmp (obj->symbols[i].n_name, "_main") || 
			!strcmp (obj->symbols[i].n_name, "main")) &&
			r_coff_rebase_sym (obj, addr, &obj->symbols[i]))
			return addr;
	}

	/* Still clueless ? Let's just use the address of .text */
	if (obj->scn_hdrs)
	for (i = 0; i < obj->hdr.f_nscns; i++) {
		if (!strcmp (obj->scn_hdrs[i].s_name, ".text")) {
			addr->paddr = obj->scn_hdrs[i].s_scnptr;
			return addr;
		}
	}

	return addr;
}

static int r_bin_coff_init_hdr(struct r_bin_coff_obj *obj) {
	ut16 magic = *(ut16 *)obj->b->buf;
	obj->endian = (magic == COFF_FILE_MACHINE_H8300)?1:0;

	(void)r_buf_fread_at (obj->b, 0, (ut8 *)&obj->hdr, obj->endian? "2S3I2S": "2s3i2s", 1);

	if (obj->hdr.f_magic == COFF_FILE_TI_COFF)
		(void)r_buf_fread_at (obj->b, R_BUF_CUR, (ut8 *)&obj->target_id, obj->endian? "S": "s", 1);

	return true;
}

static int r_bin_coff_init_opt_hdr(struct r_bin_coff_obj *obj) {
	if (!obj->hdr.f_opthdr)
		return 0;
	(void)r_buf_fread_at (obj->b, obj->hdr.f_opthdr,
		(ut8 *)&obj->opt_hdr, obj->endian? "2S6I": "2s6i", 1);
	return 0;
}

static int r_bin_coff_init_scn_hdr(struct r_bin_coff_obj *obj) {
	ut64 offset = sizeof (struct coff_hdr) + (obj->hdr.f_opthdr * sizeof (struct coff_opt_hdr));
	if (obj->hdr.f_magic == COFF_FILE_TI_COFF)
		offset += 2;
	obj->scn_hdrs = calloc(obj->hdr.f_nscns, sizeof(struct coff_scn_hdr));
	(void)r_buf_fread_at (obj->b, offset, (ut8 *)obj->scn_hdrs,
		obj->endian? "8c6I2S1I": "8c6i2s1i", obj->hdr.f_nscns);
	return 0;
}

static int r_bin_coff_init_symtable(struct r_bin_coff_obj *obj) {
	if (obj->hdr.f_nsyms >= 0xffff) // too much symbols, probably not allocatable
		return 0;
	obj->symbols = calloc (obj->hdr.f_nsyms, sizeof(struct coff_symbol));
	if (obj->symbols == NULL)
		return 0;
	(void)r_buf_fread_at (obj->b, obj->hdr.f_symptr, (ut8 *)obj->symbols,
		obj->endian? "8c1I2S2c": "8c1i2s2c", obj->hdr.f_nsyms);
	return 1;
}

static int r_bin_coff_init(struct r_bin_coff_obj *obj, RBuffer *buf) {
	obj->b = r_buf_new ();
	obj->size = buf->length;
	if (!r_buf_set_bytes (obj->b, buf->buf, obj->size)){
		r_buf_free (obj->b);
		return false;
	}
	r_bin_coff_init_hdr(obj);
	r_bin_coff_init_opt_hdr(obj);

	r_bin_coff_init_scn_hdr(obj);
	r_bin_coff_init_symtable(obj);
	return true;
}

void r_bin_coff_free(struct r_bin_coff_obj *obj) {
	free (obj->scn_hdrs);
	free (obj->symbols);
	free (obj);
}

struct r_bin_coff_obj* r_bin_coff_new_buf(struct r_buf_t *buf) {
	struct r_bin_coff_obj* bin = R_NEW0 (struct r_bin_coff_obj);
	r_bin_coff_init (bin, buf);
	return bin;
}