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: src/lib/libarchive/archive_read_open_memory.c,v 1.6 2007/07/06 15:51:59 kientzle Exp $");
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
43 struct read_memory_data {
44 unsigned char *buffer;
45 unsigned char *end;
46 ssize_t read_size;
47 };
48
49 static int memory_read_close(struct archive *, void *);
50 static int memory_read_open(struct archive *, void *);
51 #if ARCHIVE_API_VERSION < 2
52 static ssize_t memory_read_skip(struct archive *, void *, size_t request);
53 #else
54 static off_t memory_read_skip(struct archive *, void *, off_t request);
55 #endif
56 static ssize_t memory_read(struct archive *, void *, const void **buff);
57
58 int
archive_read_open_memory(struct archive * a,void * buff,size_t size)59 archive_read_open_memory(struct archive *a, void *buff, size_t size)
60 {
61 return archive_read_open_memory2(a, buff, size, size);
62 }
63
64 /*
65 * Don't use _open_memory2() in production code; the archive_read_open_memory()
66 * version is the one you really want. This is just here so that
67 * test harnesses can exercise block operations inside the library.
68 */
69 int
archive_read_open_memory2(struct archive * a,void * buff,size_t size,size_t read_size)70 archive_read_open_memory2(struct archive *a, void *buff,
71 size_t size, size_t read_size)
72 {
73 struct read_memory_data *mine;
74
75 mine = (struct read_memory_data *)malloc(sizeof(*mine));
76 if (mine == NULL) {
77 archive_set_error(a, ENOMEM, "No memory");
78 return (ARCHIVE_FATAL);
79 }
80 memset(mine, 0, sizeof(*mine));
81 mine->buffer = (unsigned char *)buff;
82 mine->end = mine->buffer + size;
83 mine->read_size = read_size;
84 return (archive_read_open2(a, mine, memory_read_open,
85 memory_read, memory_read_skip, memory_read_close));
86 }
87
88 /*
89 * There's nothing to open.
90 */
91 static int
memory_read_open(struct archive * a,void * client_data)92 memory_read_open(struct archive *a, void *client_data)
93 {
94 (void)a; /* UNUSED */
95 (void)client_data; /* UNUSED */
96 return (ARCHIVE_OK);
97 }
98
99 /*
100 * This is scary simple: Just advance a pointer. Limiting
101 * to read_size is not technically necessary, but it exercises
102 * more of the internal logic when used with a small block size
103 * in a test harness. Production use should not specify a block
104 * size; then this is much faster.
105 */
106 static ssize_t
memory_read(struct archive * a,void * client_data,const void ** buff)107 memory_read(struct archive *a, void *client_data, const void **buff)
108 {
109 struct read_memory_data *mine = (struct read_memory_data *)client_data;
110 ssize_t size;
111
112 (void)a; /* UNUSED */
113 *buff = mine->buffer;
114 size = mine->end - mine->buffer;
115 if (size > mine->read_size)
116 size = mine->read_size;
117 mine->buffer += size;
118 return (size);
119 }
120
121 /*
122 * Advancing is just as simple. Again, this is doing more than
123 * necessary in order to better exercise internal code when used
124 * as a test harness.
125 */
126 #if ARCHIVE_API_VERSION < 2
127 static ssize_t
memory_read_skip(struct archive * a,void * client_data,size_t skip)128 memory_read_skip(struct archive *a, void *client_data, size_t skip)
129 #else
130 static off_t
131 memory_read_skip(struct archive *a, void *client_data, off_t skip)
132 #endif
133 {
134 struct read_memory_data *mine = (struct read_memory_data *)client_data;
135
136 (void)a; /* UNUSED */
137 if ((off_t)skip > (off_t)(mine->end - mine->buffer))
138 skip = mine->end - mine->buffer;
139 /* Round down to block size. */
140 skip /= mine->read_size;
141 skip *= mine->read_size;
142 mine->buffer += skip;
143 return (skip);
144 }
145
146 /*
147 * Close is just cleaning up our one small bit of data.
148 */
149 static int
memory_read_close(struct archive * a,void * client_data)150 memory_read_close(struct archive *a, void *client_data)
151 {
152 struct read_memory_data *mine = (struct read_memory_data *)client_data;
153 (void)a; /* UNUSED */
154 free(mine);
155 return (ARCHIVE_OK);
156 }
157