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: stable/11/contrib/libarchive/libarchive/archive_read_open_memory.c 311041 2017-01-02 01:41:31Z 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	const unsigned char	*start;
45	const unsigned char	*p;
46	const 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, const 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, const void *buff,
69    size_t size, size_t read_size)
70{
71	struct read_memory_data *mine;
72
73	mine = (struct read_memory_data *)calloc(1, sizeof(*mine));
74	if (mine == NULL) {
75		archive_set_error(a, ENOMEM, "No memory");
76		return (ARCHIVE_FATAL);
77	}
78	mine->start = mine->p = (const unsigned char *)buff;
79	mine->end = mine->start + size;
80	mine->read_size = read_size;
81	archive_read_set_open_callback(a, memory_read_open);
82	archive_read_set_read_callback(a, memory_read);
83	archive_read_set_seek_callback(a, memory_read_seek);
84	archive_read_set_skip_callback(a, memory_read_skip);
85	archive_read_set_close_callback(a, memory_read_close);
86	archive_read_set_callback_data(a, mine);
87	return (archive_read_open1(a));
88}
89
90/*
91 * There's nothing to open.
92 */
93static int
94memory_read_open(struct archive *a, void *client_data)
95{
96	(void)a; /* UNUSED */
97	(void)client_data; /* UNUSED */
98	return (ARCHIVE_OK);
99}
100
101/*
102 * This is scary simple:  Just advance a pointer.  Limiting
103 * to read_size is not technically necessary, but it exercises
104 * more of the internal logic when used with a small block size
105 * in a test harness.  Production use should not specify a block
106 * size; then this is much faster.
107 */
108static ssize_t
109memory_read(struct archive *a, void *client_data, const void **buff)
110{
111	struct read_memory_data *mine = (struct read_memory_data *)client_data;
112	ssize_t size;
113
114	(void)a; /* UNUSED */
115	*buff = mine->p;
116	size = mine->end - mine->p;
117	if (size > mine->read_size)
118		size = mine->read_size;
119        mine->p += size;
120	return (size);
121}
122
123/*
124 * Advancing is just as simple.  Again, this is doing more than
125 * necessary in order to better exercise internal code when used
126 * as a test harness.
127 */
128static int64_t
129memory_read_skip(struct archive *a, void *client_data, int64_t skip)
130{
131	struct read_memory_data *mine = (struct read_memory_data *)client_data;
132
133	(void)a; /* UNUSED */
134	if ((int64_t)skip > (int64_t)(mine->end - mine->p))
135		skip = mine->end - mine->p;
136	/* Round down to block size. */
137	skip /= mine->read_size;
138	skip *= mine->read_size;
139	mine->p += skip;
140	return (skip);
141}
142
143/*
144 * Seeking.
145 */
146static int64_t
147memory_read_seek(struct archive *a, void *client_data, int64_t offset, int whence)
148{
149	struct read_memory_data *mine = (struct read_memory_data *)client_data;
150
151	(void)a; /* UNUSED */
152	switch (whence) {
153	case SEEK_SET:
154		mine->p = mine->start + offset;
155		break;
156	case SEEK_CUR:
157		mine->p += offset;
158		break;
159	case SEEK_END:
160		mine->p = mine->end + offset;
161		break;
162	default:
163		return ARCHIVE_FATAL;
164	}
165	if (mine->p < mine->start) {
166		mine->p = mine->start;
167		return ARCHIVE_FAILED;
168	}
169	if (mine->p > mine->end) {
170		mine->p = mine->end;
171		return ARCHIVE_FAILED;
172	}
173	return (mine->p - mine->start);
174}
175
176/*
177 * Close is just cleaning up our one small bit of data.
178 */
179static int
180memory_read_close(struct archive *a, void *client_data)
181{
182	struct read_memory_data *mine = (struct read_memory_data *)client_data;
183	(void)a; /* UNUSED */
184	free(mine);
185	return (ARCHIVE_OK);
186}
187