plugins/ctf/common/notif-iter/notif-iter.c: add logging
[babeltrace.git] / include / babeltrace / mmap-align-internal.h
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1#ifndef _BABELTRACE_MMAP_ALIGN_H
2#define _BABELTRACE_MMAP_ALIGN_H
3
4/*
5 * BabelTrace mmap-align.h - mmap alignment header
6 *
7 * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to deal
11 * in the Software without restriction, including without limitation the rights
12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 * copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
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18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
25 * SOFTWARE.
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26 */
27
3d9990ac 28#include <babeltrace/align-internal.h>
f7a2be83 29#include <stdlib.h>
544d0515 30#include <stdint.h>
8f76831a 31#include <babeltrace/compat/mman-internal.h>
108e5a1e 32#include <babeltrace/common-internal.h>
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33
34/*
35 * This header implements a wrapper over mmap (mmap_align) that memory
36 * maps a file region that is not necessarily multiple of the page size.
37 * It returns a structure (instead of a pointer) that contains the mmap
38 * pointer (page-aligned) and a pointer to the offset requested within
39 * that page. Note: in the current implementation, the "addr" parameter
40 * cannot be forced, so we allocate at an address chosen by the OS.
41 */
42
43struct mmap_align {
44 void *page_aligned_addr; /* mmap address, aligned to floor */
45 size_t page_aligned_length; /* mmap length, containing range */
46
47 void *addr; /* virtual mmap address */
48 size_t length; /* virtual mmap length */
49};
50
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51#ifdef __WIN32__
52#include <windows.h>
53
54/*
55 * On windows the memory mapping offset must be aligned to the memory
56 * allocator allocation granularity and not the page size.
57 */
58static inline
59off_t get_page_aligned_offset(off_t offset, size_t page_size)
60{
61 SYSTEM_INFO sysinfo;
62
63 GetNativeSystemInfo(&sysinfo);
64
65 return ALIGN_FLOOR(offset, sysinfo.dwAllocationGranularity);
66}
67#else
68static inline
69off_t get_page_aligned_offset(off_t offset, size_t page_size)
70{
71 return ALIGN_FLOOR(offset, page_size);
72}
73#endif
74
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75static inline
76struct mmap_align *mmap_align(size_t length, int prot,
77 int flags, int fd, off_t offset)
78{
79 struct mmap_align *mma;
80 off_t page_aligned_offset; /* mmap offset, aligned to floor */
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81 size_t page_size;
82
83 page_size = bt_common_get_page_size();
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84
85 mma = malloc(sizeof(*mma));
86 if (!mma)
87 return MAP_FAILED;
88 mma->length = length;
8f76831a 89 page_aligned_offset = get_page_aligned_offset(offset, page_size);
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90 /*
91 * Page aligned length needs to contain the requested range.
92 * E.g., for a small range that fits within a single page, we might
93 * require a 2 pages page_aligned_length if the range crosses a page
94 * boundary.
95 */
108e5a1e 96 mma->page_aligned_length = ALIGN(length + offset - page_aligned_offset, page_size);
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97 mma->page_aligned_addr = mmap(NULL, mma->page_aligned_length,
98 prot, flags, fd, page_aligned_offset);
8f76831a 99 if (mma->page_aligned_addr == MAP_FAILED) {
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100 free(mma);
101 return MAP_FAILED;
102 }
544d0515 103 mma->addr = ((uint8_t *) mma->page_aligned_addr) + (offset - page_aligned_offset);
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104 return mma;
105}
106
107static inline
108int munmap_align(struct mmap_align *mma)
109{
110 void *page_aligned_addr;
111 size_t page_aligned_length;
112
113 page_aligned_addr = mma->page_aligned_addr;
114 page_aligned_length = mma->page_aligned_length;
115 free(mma);
116 return munmap(page_aligned_addr, page_aligned_length);
117}
118
119static inline
120void *mmap_align_addr(struct mmap_align *mma)
121{
122 return mma->addr;
123}
124
125/*
126 * Helper for special-cases, normally unused.
127 */
128static inline
129void mmap_align_set_addr(struct mmap_align *mma, void *addr)
130{
131 mma->addr = addr;
132}
133
134#endif /* _BABELTRACE_MMAP_ALIGN_H */
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