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 const unsigned char *start;
45 const unsigned char *p;
46 const unsigned char *end;
47 ssize_t read_size;
48 };
49
50 static int memory_read_close(struct archive *, void *);
51 static int memory_read_open(struct archive *, void *);
52 static int64_t memory_read_seek(struct archive *, void *, int64_t offset, int whence);
53 static int64_t memory_read_skip(struct archive *, void *, int64_t request);
54 static ssize_t memory_read(struct archive *, void *, const void **buff);
55
56 int
archive_read_open_memory(struct archive * a,const void * buff,size_t size)57 archive_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 */
67 int
archive_read_open_memory2(struct archive * a,const void * buff,size_t size,size_t read_size)68 archive_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 */
93 static int
memory_read_open(struct archive * a,void * client_data)94 memory_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 */
108 static ssize_t
memory_read(struct archive * a,void * client_data,const void ** buff)109 memory_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 */
128 static int64_t
memory_read_skip(struct archive * a,void * client_data,int64_t skip)129 memory_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 */
146 static int64_t
memory_read_seek(struct archive * a,void * client_data,int64_t offset,int whence)147 memory_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 */
179 static int
memory_read_close(struct archive * a,void * client_data)180 memory_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