1/*-
2 * Copyright (c) 2012 Michihiro NAKAJIMA
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
28__FBSDID("$FreeBSD$");
29
30
31#ifdef HAVE_ERRNO_H
32#include <errno.h>
33#endif
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
44#include "archive.h"
45#include "archive_private.h"
46#include "archive_read_private.h"
47
48static const unsigned char grzip_magic[] = {
49	0x47, 0x52, 0x5a, 0x69, 0x70, 0x49, 0x49, 0x00,
50	0x02, 0x04, 0x3a, 0x29 };
51
52static int	grzip_bidder_bid(struct archive_read_filter_bidder *,
53		    struct archive_read_filter *);
54static int	grzip_bidder_init(struct archive_read_filter *);
55
56
57static int
58grzip_reader_free(struct archive_read_filter_bidder *self)
59{
60	(void)self; /* UNUSED */
61	return (ARCHIVE_OK);
62}
63
64int
65archive_read_support_filter_grzip(struct archive *_a)
66{
67	struct archive_read *a = (struct archive_read *)_a;
68	struct archive_read_filter_bidder *reader;
69
70	archive_check_magic(_a, ARCHIVE_READ_MAGIC,
71	    ARCHIVE_STATE_NEW, "archive_read_support_filter_grzip");
72
73	if (__archive_read_get_bidder(a, &reader) != ARCHIVE_OK)
74		return (ARCHIVE_FATAL);
75
76	reader->data = NULL;
77	reader->bid = grzip_bidder_bid;
78	reader->init = grzip_bidder_init;
79	reader->options = NULL;
80	reader->free = grzip_reader_free;
81	/* This filter always uses an external program. */
82	archive_set_error(_a, ARCHIVE_ERRNO_MISC,
83	    "Using external grzip program for grzip decompression");
84	return (ARCHIVE_WARN);
85}
86
87/*
88 * Bidder just verifies the header and returns the number of verified bits.
89 */
90static int
91grzip_bidder_bid(struct archive_read_filter_bidder *self,
92    struct archive_read_filter *filter)
93{
94	const unsigned char *p;
95	ssize_t avail;
96
97	(void)self; /* UNUSED */
98
99	p = __archive_read_filter_ahead(filter, sizeof(grzip_magic), &avail);
100	if (p == NULL || avail == 0)
101		return (0);
102
103	if (memcmp(p, grzip_magic, sizeof(grzip_magic)))
104		return (0);
105
106	return (sizeof(grzip_magic) * 8);
107}
108
109static int
110grzip_bidder_init(struct archive_read_filter *self)
111{
112	int r;
113
114	r = __archive_read_program(self, "grzip -d");
115	/* Note: We set the format here even if __archive_read_program()
116	 * above fails.  We do, after all, know what the format is
117	 * even if we weren't able to read it. */
118	self->code = ARCHIVE_FILTER_GRZIP;
119	self->name = "grzip";
120	return (r);
121}
122