archive_check_magic.c revision 302408 
1/*-
2 * Copyright (c) 2003-2010 Tim Kientzle
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "archive_platform.h"
27__FBSDID("$FreeBSD: stable/11/contrib/libarchive/libarchive/archive_check_magic.c 238856 2012-07-28 06:38:44Z mm $");
28
29#ifdef HAVE_SYS_TYPES_H
30#include <sys/types.h>
31#endif
32
33#include <stdio.h>
34#ifdef HAVE_STDLIB_H
35#include <stdlib.h>
36#endif
37#ifdef HAVE_STRING_H
38#include <string.h>
39#endif
40#ifdef HAVE_UNISTD_H
41#include <unistd.h>
42#endif
43#if defined(_WIN32) && !defined(__CYGWIN__)
44#include <windows.h>
45#include <winbase.h>
46#endif
47
48#include "archive_private.h"
49
50static void
51errmsg(const char *m)
52{
53	size_t s = strlen(m);
54	ssize_t written;
55
56	while (s > 0) {
57		written = write(2, m, strlen(m));
58		if (written <= 0)
59			return;
60		m += written;
61		s -= written;
62	}
63}
64
65static void
66diediedie(void)
67{
68#if defined(_WIN32) && !defined(__CYGWIN__) && defined(_DEBUG)
69	/* Cause a breakpoint exception  */
70	DebugBreak();
71#endif
72	abort();        /* Terminate the program abnormally. */
73}
74
75static const char *
76state_name(unsigned s)
77{
78	switch (s) {
79	case ARCHIVE_STATE_NEW:		return ("new");
80	case ARCHIVE_STATE_HEADER:	return ("header");
81	case ARCHIVE_STATE_DATA:	return ("data");
82	case ARCHIVE_STATE_EOF:		return ("eof");
83	case ARCHIVE_STATE_CLOSED:	return ("closed");
84	case ARCHIVE_STATE_FATAL:	return ("fatal");
85	default:			return ("??");
86	}
87}
88
89static const char *
90archive_handle_type_name(unsigned m)
91{
92	switch (m) {
93	case ARCHIVE_WRITE_MAGIC:	return ("archive_write");
94	case ARCHIVE_READ_MAGIC:	return ("archive_read");
95	case ARCHIVE_WRITE_DISK_MAGIC:	return ("archive_write_disk");
96	case ARCHIVE_READ_DISK_MAGIC:	return ("archive_read_disk");
97	case ARCHIVE_MATCH_MAGIC:	return ("archive_match");
98	default:			return NULL;
99	}
100}
101
102
103static char *
104write_all_states(char *buff, unsigned int states)
105{
106	unsigned int lowbit;
107
108	buff[0] = '\0';
109
110	/* A trick for computing the lowest set bit. */
111	while ((lowbit = states & (1 + ~states)) != 0) {
112		states &= ~lowbit;		/* Clear the low bit. */
113		strcat(buff, state_name(lowbit));
114		if (states != 0)
115			strcat(buff, "/");
116	}
117	return buff;
118}
119
120/*
121 * Check magic value and current state.
122 *   Magic value mismatches are fatal and result in calls to abort().
123 *   State mismatches return ARCHIVE_FATAL.
124 *   Otherwise, returns ARCHIVE_OK.
125 *
126 * This is designed to catch serious programming errors that violate
127 * the libarchive API.
128 */
129int
130__archive_check_magic(struct archive *a, unsigned int magic,
131    unsigned int state, const char *function)
132{
133	char states1[64];
134	char states2[64];
135	const char *handle_type;
136
137	/*
138	 * If this isn't some form of archive handle,
139	 * then the library user has screwed up so bad that
140	 * we don't even have a reliable way to report an error.
141	 */
142	handle_type = archive_handle_type_name(a->magic);
143
144	if (!handle_type) {
145		errmsg("PROGRAMMER ERROR: Function ");
146		errmsg(function);
147		errmsg(" invoked with invalid archive handle.\n");
148		diediedie();
149	}
150
151	if (a->magic != magic) {
152		archive_set_error(a, -1,
153		    "PROGRAMMER ERROR: Function '%s' invoked"
154		    " on '%s' archive object, which is not supported.",
155		    function,
156		    handle_type);
157		a->state = ARCHIVE_STATE_FATAL;
158		return (ARCHIVE_FATAL);
159	}
160
161	if ((a->state & state) == 0) {
162		/* If we're already FATAL, don't overwrite the error. */
163		if (a->state != ARCHIVE_STATE_FATAL)
164			archive_set_error(a, -1,
165			    "INTERNAL ERROR: Function '%s' invoked with"
166			    " archive structure in state '%s',"
167			    " should be in state '%s'",
168			    function,
169			    write_all_states(states1, a->state),
170			    write_all_states(states2, state));
171		a->state = ARCHIVE_STATE_FATAL;
172		return (ARCHIVE_FATAL);
173	}
174	return ARCHIVE_OK;
175}
176