archive_read_support_format_raw.c revision 228763 
1/*-
2 * Copyright (c) 2003-2009 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#include "archive_platform.h"
26__FBSDID("$FreeBSD: head/contrib/libarchive/libarchive/archive_read_support_format_raw.c 228763 2011-12-21 11:13:29Z mm $");
27
28#ifdef HAVE_ERRNO_H
29#include <errno.h>
30#endif
31#include <stdio.h>
32#ifdef HAVE_STDLIB_H
33#include <stdlib.h>
34#endif
35
36#include "archive.h"
37#include "archive_entry.h"
38#include "archive_private.h"
39#include "archive_read_private.h"
40
41struct raw_info {
42	int64_t offset; /* Current position in the file. */
43	int     end_of_file;
44};
45
46static int	archive_read_format_raw_bid(struct archive_read *);
47static int	archive_read_format_raw_cleanup(struct archive_read *);
48static int	archive_read_format_raw_read_data(struct archive_read *,
49		    const void **, size_t *, off_t *);
50static int	archive_read_format_raw_read_data_skip(struct archive_read *);
51static int	archive_read_format_raw_read_header(struct archive_read *,
52		    struct archive_entry *);
53
54int
55archive_read_support_format_raw(struct archive *_a)
56{
57	struct raw_info *info;
58	struct archive_read *a = (struct archive_read *)_a;
59	int r;
60
61	info = (struct raw_info *)calloc(1, sizeof(*info));
62	if (info == NULL) {
63		archive_set_error(&a->archive, ENOMEM,
64		    "Can't allocate raw_info data");
65		return (ARCHIVE_FATAL);
66	}
67
68	r = __archive_read_register_format(a,
69	    info,
70	    "raw",
71	    archive_read_format_raw_bid,
72	    NULL,
73	    archive_read_format_raw_read_header,
74	    archive_read_format_raw_read_data,
75	    archive_read_format_raw_read_data_skip,
76	    archive_read_format_raw_cleanup);
77	if (r != ARCHIVE_OK)
78		free(info);
79	return (r);
80}
81
82/*
83 * Bid 1 if this is a non-empty file.  Anyone who can really support
84 * this should outbid us, so it should generally be safe to use "raw"
85 * in conjunction with other formats.  But, this could really confuse
86 * folks if there are bid errors or minor file damage, so we don't
87 * include "raw" as part of support_format_all().
88 */
89static int
90archive_read_format_raw_bid(struct archive_read *a)
91{
92
93	if (__archive_read_ahead(a, 1, NULL) == NULL)
94		return (-1);
95	return (1);
96}
97
98/*
99 * Mock up a fake header.
100 */
101static int
102archive_read_format_raw_read_header(struct archive_read *a,
103    struct archive_entry *entry)
104{
105	struct raw_info *info;
106
107	info = (struct raw_info *)(a->format->data);
108	if (info->end_of_file)
109		return (ARCHIVE_EOF);
110
111	a->archive.archive_format = ARCHIVE_FORMAT_RAW;
112	a->archive.archive_format_name = "Raw data";
113	archive_entry_set_pathname(entry, "data");
114	/* XXX should we set mode to mimic a regular file? XXX */
115	/* I'm deliberately leaving most fields unset here. */
116	return (ARCHIVE_OK);
117}
118
119static int
120archive_read_format_raw_read_data(struct archive_read *a,
121    const void **buff, size_t *size, off_t *offset)
122{
123	struct raw_info *info;
124	ssize_t avail;
125
126	info = (struct raw_info *)(a->format->data);
127	if (info->end_of_file)
128		return (ARCHIVE_EOF);
129
130	/* Get whatever bytes are immediately available. */
131	*buff = __archive_read_ahead(a, 1, &avail);
132	if (avail > 0) {
133		/* Consume and return the bytes we just read */
134		__archive_read_consume(a, avail);
135		*size = avail;
136		*offset = info->offset;
137		info->offset += *size;
138		return (ARCHIVE_OK);
139	} else if (0 == avail) {
140		/* Record and return end-of-file. */
141		info->end_of_file = 1;
142		*size = 0;
143		*offset = info->offset;
144		return (ARCHIVE_EOF);
145	} else {
146		/* Record and return an error. */
147		*size = 0;
148		*offset = info->offset;
149		return (avail);
150	}
151}
152
153static int
154archive_read_format_raw_read_data_skip(struct archive_read *a)
155{
156	struct raw_info *info;
157	off_t bytes_skipped;
158	int64_t request = 1024 * 1024 * 1024UL; /* Skip 1 GB at a time. */
159
160	info = (struct raw_info *)(a->format->data);
161	if (info->end_of_file)
162		return (ARCHIVE_EOF);
163	info->end_of_file = 1;
164
165	for (;;) {
166		bytes_skipped = __archive_read_skip_lenient(a, request);
167		if (bytes_skipped < 0)
168			return (ARCHIVE_FATAL);
169		if (bytes_skipped < request)
170			return (ARCHIVE_OK);
171		/* We skipped all the bytes we asked for.  There might
172		 * be more, so try again. */
173	}
174}
175
176static int
177archive_read_format_raw_cleanup(struct archive_read *a)
178{
179	struct raw_info *info;
180
181	info = (struct raw_info *)(a->format->data);
182	free(info);
183	a->format->data = NULL;
184	return (ARCHIVE_OK);
185}
186