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