1 #ifndef _BABELTRACE_MMAP_ALIGN_H
2 #define _BABELTRACE_MMAP_ALIGN_H
5 * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
26 #include <babeltrace/align-internal.h>
29 #include <babeltrace/compat/mman-internal.h>
30 #include <babeltrace/common-internal.h>
33 * This header implements a wrapper over mmap (mmap_align) that memory
34 * maps a file region that is not necessarily multiple of the page size.
35 * It returns a structure (instead of a pointer) that contains the mmap
36 * pointer (page-aligned) and a pointer to the offset requested within
37 * that page. Note: in the current implementation, the "addr" parameter
38 * cannot be forced, so we allocate at an address chosen by the OS.
42 void *page_aligned_addr
; /* mmap address, aligned to floor */
43 size_t page_aligned_length
; /* mmap length, containing range */
45 void *addr
; /* virtual mmap address */
46 size_t length
; /* virtual mmap length */
53 * On windows the memory mapping offset must be aligned to the memory
54 * allocator allocation granularity and not the page size.
57 off_t
get_page_aligned_offset(off_t offset
, size_t page_size
)
61 GetNativeSystemInfo(&sysinfo
);
63 return ALIGN_FLOOR(offset
, sysinfo
.dwAllocationGranularity
);
67 off_t
get_page_aligned_offset(off_t offset
, size_t page_size
)
69 return ALIGN_FLOOR(offset
, page_size
);
74 struct mmap_align
*mmap_align(size_t length
, int prot
,
75 int flags
, int fd
, off_t offset
)
77 struct mmap_align
*mma
;
78 off_t page_aligned_offset
; /* mmap offset, aligned to floor */
81 page_size
= bt_common_get_page_size();
83 mma
= malloc(sizeof(*mma
));
87 page_aligned_offset
= get_page_aligned_offset(offset
, page_size
);
89 * Page aligned length needs to contain the requested range.
90 * E.g., for a small range that fits within a single page, we might
91 * require a 2 pages page_aligned_length if the range crosses a page
94 mma
->page_aligned_length
= ALIGN(length
+ offset
- page_aligned_offset
, page_size
);
95 mma
->page_aligned_addr
= bt_mmap(NULL
, mma
->page_aligned_length
,
96 prot
, flags
, fd
, page_aligned_offset
);
97 if (mma
->page_aligned_addr
== MAP_FAILED
) {
101 mma
->addr
= ((uint8_t *) mma
->page_aligned_addr
) + (offset
- page_aligned_offset
);
106 int munmap_align(struct mmap_align
*mma
)
108 void *page_aligned_addr
;
109 size_t page_aligned_length
;
111 page_aligned_addr
= mma
->page_aligned_addr
;
112 page_aligned_length
= mma
->page_aligned_length
;
114 return bt_munmap(page_aligned_addr
, page_aligned_length
);
118 void *mmap_align_addr(struct mmap_align
*mma
)
124 * Helper for special-cases, normally unused.
127 void mmap_align_set_addr(struct mmap_align
*mma
, void *addr
)
132 #endif /* _BABELTRACE_MMAP_ALIGN_H */