1/*-
2 * Copyright (c) 2003-2007 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: releng/10.3/contrib/libarchive/libarchive/archive_read_open_memory.c 232153 2012-02-25 10:58:02Z mm $");
28
29#include <errno.h>
30#include <stdlib.h>
31#include <string.h>
32
33#include "archive.h"
34
35/*
36 * Glue to read an archive from a block of memory.
37 *
38 * This is mostly a huge help in building test harnesses;
39 * test programs can build archives in memory and read them
40 * back again without having to mess with files on disk.
41 */
42
43struct read_memory_data {
44	unsigned char	*start;
45	unsigned char	*p;
46	unsigned char	*end;
47	ssize_t	 read_size;
48};
49
50static int	memory_read_close(struct archive *, void *);
51static int	memory_read_open(struct archive *, void *);
52static int64_t	memory_read_seek(struct archive *, void *, int64_t offset, int whence);
53static int64_t	memory_read_skip(struct archive *, void *, int64_t request);
54static ssize_t	memory_read(struct archive *, void *, const void **buff);
55
56int
57archive_read_open_memory(struct archive *a, void *buff, size_t size)
58{
59	return archive_read_open_memory2(a, buff, size, size);
60}
61
62/*
63 * Don't use _open_memory2() in production code; the archive_read_open_memory()
64 * version is the one you really want.  This is just here so that
65 * test harnesses can exercise block operations inside the library.
66 */
67int
68archive_read_open_memory2(struct archive *a, void *buff,
69    size_t size, size_t read_size)
70{
71	struct read_memory_data *mine;
72
73	mine = (struct read_memory_data *)malloc(sizeof(*mine));
74	if (mine == NULL) {
75		archive_set_error(a, ENOMEM, "No memory");
76		return (ARCHIVE_FATAL);
77	}
78	memset(mine, 0, sizeof(*mine));
79	mine->start = mine->p = (unsigned char *)buff;
80	mine->end = mine->start + size;
81	mine->read_size = read_size;
82	archive_read_set_open_callback(a, memory_read_open);
83	archive_read_set_read_callback(a, memory_read);
84	archive_read_set_seek_callback(a, memory_read_seek);
85	archive_read_set_skip_callback(a, memory_read_skip);
86	archive_read_set_close_callback(a, memory_read_close);
87	archive_read_set_callback_data(a, mine);
88	return (archive_read_open1(a));
89}
90
91/*
92 * There's nothing to open.
93 */
94static int
95memory_read_open(struct archive *a, void *client_data)
96{
97	(void)a; /* UNUSED */
98	(void)client_data; /* UNUSED */
99	return (ARCHIVE_OK);
100}
101
102/*
103 * This is scary simple:  Just advance a pointer.  Limiting
104 * to read_size is not technically necessary, but it exercises
105 * more of the internal logic when used with a small block size
106 * in a test harness.  Production use should not specify a block
107 * size; then this is much faster.
108 */
109static ssize_t
110memory_read(struct archive *a, void *client_data, const void **buff)
111{
112	struct read_memory_data *mine = (struct read_memory_data *)client_data;
113	ssize_t size;
114
115	(void)a; /* UNUSED */
116	*buff = mine->p;
117	size = mine->end - mine->p;
118	if (size > mine->read_size)
119		size = mine->read_size;
120        mine->p += size;
121	return (size);
122}
123
124/*
125 * Advancing is just as simple.  Again, this is doing more than
126 * necessary in order to better exercise internal code when used
127 * as a test harness.
128 */
129static int64_t
130memory_read_skip(struct archive *a, void *client_data, int64_t skip)
131{
132	struct read_memory_data *mine = (struct read_memory_data *)client_data;
133
134	(void)a; /* UNUSED */
135	if ((int64_t)skip > (int64_t)(mine->end - mine->p))
136		skip = mine->end - mine->p;
137	/* Round down to block size. */
138	skip /= mine->read_size;
139	skip *= mine->read_size;
140	mine->p += skip;
141	return (skip);
142}
143
144/*
145 * Seeking.
146 */
147static int64_t
148memory_read_seek(struct archive *a, void *client_data, int64_t offset, int whence)
149{
150	struct read_memory_data *mine = (struct read_memory_data *)client_data;
151
152	(void)a; /* UNUSED */
153	switch (whence) {
154	case SEEK_SET:
155		mine->p = mine->start + offset;
156		break;
157	case SEEK_CUR:
158		mine->p += offset;
159		break;
160	case SEEK_END:
161		mine->p = mine->end + offset;
162		break;
163	default:
164		return ARCHIVE_FATAL;
165	}
166	if (mine->p < mine->start) {
167		mine->p = mine->start;
168		return ARCHIVE_FAILED;
169	}
170	if (mine->p > mine->end) {
171		mine->p = mine->end;
172		return ARCHIVE_FAILED;
173	}
174	return (mine->p - mine->start);
175}
176
177/*
178 * Close is just cleaning up our one small bit of data.
179 */
180static int
181memory_read_close(struct archive *a, void *client_data)
182{
183	struct read_memory_data *mine = (struct read_memory_data *)client_data;
184	(void)a; /* UNUSED */
185	free(mine);
186	return (ARCHIVE_OK);
187}
188