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
28 #include <errno.h>
29 #include <stdlib.h>
30 #include <string.h>
31
32 #include "archive.h"
33
34 /*
35 * Glue to read an archive from a block of memory.
36 *
37 * This is mostly a huge help in building test harnesses;
38 * test programs can build archives in memory and read them
39 * back again without having to mess with files on disk.
40 */
41
42 struct read_memory_data {
43 const unsigned char *start;
44 const unsigned char *p;
45 const 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 static int64_t memory_read_seek(struct archive *, void *, int64_t offset, int whence);
52 static int64_t memory_read_skip(struct archive *, void *, int64_t request);
53 static ssize_t memory_read(struct archive *, void *, const void **buff);
54
55 int
archive_read_open_memory(struct archive * a,const void * buff,size_t size)56 archive_read_open_memory(struct archive *a, const void *buff, size_t size)
57 {
58 return archive_read_open_memory2(a, buff, size, size);
59 }
60
61 /*
62 * Don't use _open_memory2() in production code; the archive_read_open_memory()
63 * version is the one you really want. This is just here so that
64 * test harnesses can exercise block operations inside the library.
65 */
66 int
archive_read_open_memory2(struct archive * a,const void * buff,size_t size,size_t read_size)67 archive_read_open_memory2(struct archive *a, const void *buff,
68 size_t size, size_t read_size)
69 {
70 struct read_memory_data *mine;
71 int r;
72
73 mine = 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 r = archive_read_set_callback_data(a, mine);
87 if (r < 0)
88 return (r);
89 return (archive_read_open1(a));
90 }
91
92 /*
93 * There's nothing to open.
94 */
95 static int
memory_read_open(struct archive * a,void * client_data)96 memory_read_open(struct archive *a, void *client_data)
97 {
98 (void)a; /* UNUSED */
99 (void)client_data; /* UNUSED */
100 return (ARCHIVE_OK);
101 }
102
103 /*
104 * This is scary simple: Just advance a pointer. Limiting
105 * to read_size is not technically necessary, but it exercises
106 * more of the internal logic when used with a small block size
107 * in a test harness. Production use should not specify a block
108 * size; then this is much faster.
109 */
110 static ssize_t
memory_read(struct archive * a,void * client_data,const void ** buff)111 memory_read(struct archive *a, void *client_data, const void **buff)
112 {
113 struct read_memory_data *mine = (struct read_memory_data *)client_data;
114 ssize_t size;
115
116 (void)a; /* UNUSED */
117 *buff = mine->p;
118 size = mine->end - mine->p;
119 if (size > mine->read_size)
120 size = mine->read_size;
121 mine->p += size;
122 return (size);
123 }
124
125 /*
126 * Advancing is just as simple. Again, this is doing more than
127 * necessary in order to better exercise internal code when used
128 * as a test harness.
129 */
130 static int64_t
memory_read_skip(struct archive * a,void * client_data,int64_t skip)131 memory_read_skip(struct archive *a, void *client_data, int64_t skip)
132 {
133 struct read_memory_data *mine = (struct read_memory_data *)client_data;
134
135 (void)a; /* UNUSED */
136 if ((int64_t)skip > (int64_t)(mine->end - mine->p))
137 skip = mine->end - mine->p;
138 /* Round down to block size. */
139 skip /= mine->read_size;
140 skip *= mine->read_size;
141 mine->p += skip;
142 return (skip);
143 }
144
145 /*
146 * Seeking.
147 */
148 static int64_t
memory_read_seek(struct archive * a,void * client_data,int64_t offset,int whence)149 memory_read_seek(struct archive *a, void *client_data, int64_t offset, int whence)
150 {
151 struct read_memory_data *mine = (struct read_memory_data *)client_data;
152
153 (void)a; /* UNUSED */
154 switch (whence) {
155 case SEEK_SET:
156 mine->p = mine->start + offset;
157 break;
158 case SEEK_CUR:
159 mine->p += offset;
160 break;
161 case SEEK_END:
162 mine->p = mine->end + offset;
163 break;
164 default:
165 return ARCHIVE_FATAL;
166 }
167 if (mine->p < mine->start) {
168 mine->p = mine->start;
169 return ARCHIVE_FAILED;
170 }
171 if (mine->p > mine->end) {
172 mine->p = mine->end;
173 return ARCHIVE_FAILED;
174 }
175 return (mine->p - mine->start);
176 }
177
178 /*
179 * Close is just cleaning up our one small bit of data.
180 */
181 static int
memory_read_close(struct archive * a,void * client_data)182 memory_read_close(struct archive *a, void *client_data)
183 {
184 struct read_memory_data *mine = (struct read_memory_data *)client_data;
185 (void)a; /* UNUSED */
186 free(mine);
187 return (ARCHIVE_OK);
188 }
189