xref: /PHP-7.3/main/streams/mmap.c (revision a5e80b22)
1 /*
2   +----------------------------------------------------------------------+
3   | PHP Version 7                                                        |
4   +----------------------------------------------------------------------+
5   | Copyright (c) 1997-2018 The PHP Group                                |
6   +----------------------------------------------------------------------+
7   | This source file is subject to version 3.01 of the PHP license,      |
8   | that is bundled with this package in the file LICENSE, and is        |
9   | available through the world-wide-web at the following url:           |
10   | http://www.php.net/license/3_01.txt                                  |
11   | If you did not receive a copy of the PHP license and are unable to   |
12   | obtain it through the world-wide-web, please send a note to          |
13   | license@php.net so we can mail you a copy immediately.               |
14   +----------------------------------------------------------------------+
15   | Author: Wez Furlong <wez@thebrainroom.com>                           |
16   +----------------------------------------------------------------------+
17 */
18 
19 /* Memory Mapping interface for streams */
20 #include "php.h"
21 #include "php_streams_int.h"
22 
_php_stream_mmap_range(php_stream * stream,size_t offset,size_t length,php_stream_mmap_access_t mode,size_t * mapped_len)23 PHPAPI char *_php_stream_mmap_range(php_stream *stream, size_t offset, size_t length, php_stream_mmap_access_t mode, size_t *mapped_len)
24 {
25 	php_stream_mmap_range range;
26 
27 	range.offset = offset;
28 	range.length = length;
29 	range.mode = mode;
30 	range.mapped = NULL;
31 
32 	/* For now, we impose an arbitrary limit to avoid
33 	 * runaway swapping when large files are passed through. */
34 	if (length > 4 * 1024 * 1024) {
35 		return NULL;
36 	}
37 
38 	if (PHP_STREAM_OPTION_RETURN_OK == php_stream_set_option(stream, PHP_STREAM_OPTION_MMAP_API, PHP_STREAM_MMAP_MAP_RANGE, &range)) {
39 		if (mapped_len) {
40 			*mapped_len = range.length;
41 		}
42 		return range.mapped;
43 	}
44 	return NULL;
45 }
46 
_php_stream_mmap_unmap(php_stream * stream)47 PHPAPI int _php_stream_mmap_unmap(php_stream *stream)
48 {
49 	return php_stream_set_option(stream, PHP_STREAM_OPTION_MMAP_API, PHP_STREAM_MMAP_UNMAP, NULL) == PHP_STREAM_OPTION_RETURN_OK ? 1 : 0;
50 }
51 
_php_stream_mmap_unmap_ex(php_stream * stream,zend_off_t readden)52 PHPAPI int _php_stream_mmap_unmap_ex(php_stream *stream, zend_off_t readden)
53 {
54 	int ret = 1;
55 
56 	if (php_stream_seek(stream, readden, SEEK_CUR) != 0) {
57 		ret = 0;
58 	}
59 	if (php_stream_mmap_unmap(stream) == 0) {
60 		ret = 0;
61 	}
62 
63 	return ret;
64 }
65 
66 /*
67  * Local variables:
68  * tab-width: 4
69  * c-basic-offset: 4
70  * End:
71  * vim600: noet sw=4 ts=4 fdm=marker
72  * vim<600: noet sw=4 ts=4
73  */
74