/*-

 * Copyright (c) 2003-2010 Tim Kientzle

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "archive_platform.h"

__FBSDID("$FreeBSD: head/lib/libarchive/archive_check_magic.c 201089 2009-12-28 02:20:23Z kientzle $");

#ifdef HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif

#include <stdio.h>

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_STRING_H

#include <string.h>

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#if defined(_WIN32) && !defined(__CYGWIN__)

#include <windows.h>

#include <winbase.h>

#endif

#include "archive_private.h"

static void

errmsg(const char *m)

{

	size_t s = strlen(m);

	ssize_t written;

	while (s > 0) {

		written = write(2, m, strlen(m));

		if (written <= 0)

			return;

		m += written;

		s -= written;

	}

}

static __LA_DEAD void

diediedie(void)

{

#if defined(_WIN32) && !defined(__CYGWIN__) && defined(_DEBUG)

	/* Cause a breakpoint exception  */

	DebugBreak();

#endif

	abort();        /* Terminate the program abnormally. */

}

static const char *

state_name(unsigned s)

{

	switch (s) {

	case ARCHIVE_STATE_NEW:		return ("new");

	case ARCHIVE_STATE_HEADER:	return ("header");

	case ARCHIVE_STATE_DATA:	return ("data");

	case ARCHIVE_STATE_EOF:		return ("eof");

	case ARCHIVE_STATE_CLOSED:	return ("closed");

	case ARCHIVE_STATE_FATAL:	return ("fatal");

	default:			return ("??");

	}

}

static const char *

archive_handle_type_name(unsigned m)

{

	switch (m) {

	case ARCHIVE_WRITE_MAGIC:	return ("archive_write");

	case ARCHIVE_READ_MAGIC:	return ("archive_read");

	case ARCHIVE_WRITE_DISK_MAGIC:	return ("archive_write_disk");

	case ARCHIVE_READ_DISK_MAGIC:	return ("archive_read_disk");

	case ARCHIVE_MATCH_MAGIC:	return ("archive_match");

	default:			return NULL;

	}

}

static char *

write_all_states(char *buff, unsigned int states)

{

	unsigned int lowbit;

	buff[0] = '\0';

	/* A trick for computing the lowest set bit. */

	while ((lowbit = states & (1 + ~states)) != 0) {

		states &= ~lowbit;		/* Clear the low bit. */

		strcat(buff, state_name(lowbit));

		if (states != 0)

			strcat(buff, "/");

	}

	return buff;

}

/*

 * Check magic value and current state.

 *   Magic value mismatches are fatal and result in calls to abort().

 *   State mismatches return ARCHIVE_FATAL.

 *   Otherwise, returns ARCHIVE_OK.

 *

 * This is designed to catch serious programming errors that violate

 * the libarchive API.

 */

int

__archive_check_magic(struct archive *a, unsigned int magic,

    unsigned int state, const char *function)

{

	char states1[64];

	char states2[64];

	const char *handle_type;

	/*

	 * If this isn't some form of archive handle,

	 * then the library user has screwed up so bad that

	 * we don't even have a reliable way to report an error.

	 */

	handle_type = archive_handle_type_name(a->magic);

	if (!handle_type) {

		errmsg("PROGRAMMER ERROR: Function ");

		errmsg(function);

		errmsg(" invoked with invalid archive handle.\n");

		diediedie();

	}

	if (a->magic != magic) {

		archive_set_error(a, -1,

		    "PROGRAMMER ERROR: Function '%s' invoked"

		    " on '%s' archive object, which is not supported.",

		    function,

		    handle_type);

		a->state = ARCHIVE_STATE_FATAL;

		return (ARCHIVE_FATAL);

	}

	if ((a->state & state) == 0) {

		/* If we're already FATAL, don't overwrite the error. */

		if (a->state != ARCHIVE_STATE_FATAL)

			archive_set_error(a, -1,

			    "INTERNAL ERROR: Function '%s' invoked with"

			    " archive structure in state '%s',"

			    " should be in state '%s'",

			    function,

			    write_all_states(states1, a->state),

			    write_all_states(states2, state));

		a->state = ARCHIVE_STATE_FATAL;

		return (ARCHIVE_FATAL);

	}

	return ARCHIVE_OK;

}