/* $Id: UWelfviewer.c,v 1.8 2018/04/16 00:51:46 khorben Exp $ */
/* ELF file parser
 * UberWall security team \../. .\../ */
/* Copyright (c) 2010 khorben of UberWall */
/* This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
/* FIXME:
 * - list the libraries required, RPATH set, etc */



#include <unistd.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <elf.h>
#include "elf.h"
#include "UWelfviewer.h"
#include "config.h"


/* UWelfviewer */
/* private */
/* prototypes */
static int _UWelfviewer(char const * pathname);
static int _UWelfviewer_do(FILE * fp, char const * pathname);

static int _usage(void);


/* UWelfviewer */
/* public */
/* functions */
/* UWelfviewer_error */
int UWelfviewer_error(char const * format, ...)
{
	va_list ap;

	fputs(PACKAGE ": ", stderr);
	va_start(ap, format);
	vfprintf(stderr, format, ap);
	va_end(ap);
	fputc('\n', stderr);
	return 1;
}


/* private */
/* functions */
/* UWelfviewer */
static int _UWelfviewer(char const * pathname)
{
	int ret;
	FILE * fp;

	if((fp = fopen(pathname, "r")) == NULL)
		return UWelfviewer_error("%s: %s", pathname, strerror(errno));
	ret = _UWelfviewer_do(fp, pathname);
	if(fclose(fp) != 0)
		return UWelfviewer_error("%s: %s", pathname, strerror(errno));
	return ret;
}


/* UWelfviewer_do */
static int _do_ident(FILE * fp, char const * pathname, unsigned char * ident,
		size_t size);

static int _UWelfviewer_do(FILE * fp, char const * pathname)
{
	int ret;
	unsigned char ident[ELF_NIDENT];

	if((ret = _do_ident(fp, pathname, ident, sizeof(ident))) != 0)
		return ret;
	if(fseeko(fp, 0, SEEK_SET) != 0)
		return UWelfviewer_error("%s: %s", strerror(errno));
	switch(ident[EI_CLASS])
	{
		case ELFCLASS32:
			ret = elf32(fp, pathname);
			break;
		case ELFCLASS64:
			ret = elf64(fp, pathname);
			break;
		default:
			ret = UWelfviewer_error("%u: %s", ident[EI_CLASS],
					"Unsupported ELF class");
			break;
	}
	return ret;
}

static int _do_ident(FILE * fp, char const * pathname, unsigned char * ident,
		size_t size)
{
	if(fread(ident, size, 1, fp) != 1)
		return UWelfviewer_error("%s: %s", pathname, strerror(errno));
	if(memcmp(ident, ELFMAG, sizeof(ELFMAG) - 1) != 0)
		return UWelfviewer_error("%s: %s", pathname,
				"Not an ELF file");
	return 0;
}


/* usage */
static int _usage(void)
{
	fputs("Usage: " PACKAGE " filename\n", stderr);
	return 1;
}


/* public */
/* functions */
/* main */
int main(int argc, char * argv[])
{
	int o;

	while((o = getopt(argc, argv, "")) != -1)
		return _usage();
	if(optind + 1 != argc)
		return _usage();
	return _UWelfviewer(argv[optind]) == 0 ? 0 : 2;
}