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bb742ede | 1 | /* |
5e0de328 | 2 | * Copyright (C) 2009-2012 the libgit2 contributors |
bb742ede VM |
3 | * |
4 | * This file is part of libgit2, distributed under the GNU GPL v2 with | |
5 | * a Linking Exception. For full terms see the included COPYING file. | |
6 | */ | |
79ca2edc RJ |
7 | |
8 | #include "map.h" | |
9 | #include <errno.h> | |
10 | ||
11 | ||
12 | static DWORD get_page_size(void) | |
13 | { | |
14 | static DWORD page_size; | |
15 | SYSTEM_INFO sys; | |
16 | ||
17 | if (!page_size) { | |
18 | GetSystemInfo(&sys); | |
19 | page_size = sys.dwAllocationGranularity; | |
20 | } | |
21 | ||
22 | return page_size; | |
23 | } | |
24 | ||
f79026b4 | 25 | int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offset) |
79ca2edc RJ |
26 | { |
27 | HANDLE fh = (HANDLE)_get_osfhandle(fd); | |
28 | DWORD page_size = get_page_size(); | |
29 | DWORD fmap_prot = 0; | |
30 | DWORD view_prot = 0; | |
31 | DWORD off_low = 0; | |
87d9869f | 32 | DWORD off_hi = 0; |
f0bde7fa AB |
33 | git_off_t page_start; |
34 | git_off_t page_offset; | |
79ca2edc RJ |
35 | |
36 | assert((out != NULL) && (len > 0)); | |
37 | ||
38 | if ((out == NULL) || (len == 0)) { | |
39 | errno = EINVAL; | |
7c8b597e | 40 | return git__throw(GIT_ERROR, "Failed to mmap. No map or zero length"); |
79ca2edc RJ |
41 | } |
42 | ||
43 | out->data = NULL; | |
44 | out->len = 0; | |
45 | out->fmh = NULL; | |
46 | ||
47 | if (fh == INVALID_HANDLE_VALUE) { | |
48 | errno = EBADF; | |
7c8b597e | 49 | return git__throw(GIT_ERROR, "Failed to mmap. Invalid handle value"); |
79ca2edc RJ |
50 | } |
51 | ||
52 | if (prot & GIT_PROT_WRITE) | |
53 | fmap_prot |= PAGE_READWRITE; | |
54 | else if (prot & GIT_PROT_READ) | |
55 | fmap_prot |= PAGE_READONLY; | |
56 | else { | |
57 | errno = EINVAL; | |
7c8b597e | 58 | return git__throw(GIT_ERROR, "Failed to mmap. Invalid protection parameters"); |
79ca2edc RJ |
59 | } |
60 | ||
61 | if (prot & GIT_PROT_WRITE) | |
62 | view_prot |= FILE_MAP_WRITE; | |
63 | if (prot & GIT_PROT_READ) | |
64 | view_prot |= FILE_MAP_READ; | |
65 | ||
66 | if (flags & GIT_MAP_FIXED) { | |
67 | errno = EINVAL; | |
7c8b597e | 68 | return git__throw(GIT_ERROR, "Failed to mmap. FIXED not set"); |
79ca2edc RJ |
69 | } |
70 | ||
71 | page_start = (offset / page_size) * page_size; | |
72 | page_offset = offset - page_start; | |
73 | ||
87d9869f | 74 | if (page_offset != 0) { /* offset must be multiple of page size */ |
79ca2edc | 75 | errno = EINVAL; |
7c8b597e | 76 | return git__throw(GIT_ERROR, "Failed to mmap. Offset must be multiple of page size"); |
79ca2edc RJ |
77 | } |
78 | ||
79 | out->fmh = CreateFileMapping(fh, NULL, fmap_prot, 0, 0, NULL); | |
80 | if (!out->fmh || out->fmh == INVALID_HANDLE_VALUE) { | |
81 | /* errno = ? */ | |
82 | out->fmh = NULL; | |
7c8b597e | 83 | return git__throw(GIT_ERROR, "Failed to mmap. Invalid handle value"); |
79ca2edc RJ |
84 | } |
85 | ||
f0bde7fa | 86 | assert(sizeof(git_off_t) == 8); |
79ca2edc | 87 | off_low = (DWORD)(page_start); |
90d4d2f0 | 88 | off_hi = (DWORD)(page_start >> 32); |
79ca2edc RJ |
89 | out->data = MapViewOfFile(out->fmh, view_prot, off_hi, off_low, len); |
90 | if (!out->data) { | |
91 | /* errno = ? */ | |
92 | CloseHandle(out->fmh); | |
93 | out->fmh = NULL; | |
7c8b597e | 94 | return git__throw(GIT_ERROR, "Failed to mmap. No data written"); |
79ca2edc RJ |
95 | } |
96 | out->len = len; | |
97 | ||
98 | return GIT_SUCCESS; | |
99 | } | |
100 | ||
f79026b4 | 101 | int p_munmap(git_map *map) |
79ca2edc RJ |
102 | { |
103 | assert(map != NULL); | |
104 | ||
105 | if (!map) | |
7c8b597e | 106 | return git__throw(GIT_ERROR, "Failed to munmap. Map does not exist"); |
79ca2edc RJ |
107 | |
108 | if (map->data) { | |
109 | if (!UnmapViewOfFile(map->data)) { | |
110 | /* errno = ? */ | |
111 | CloseHandle(map->fmh); | |
112 | map->data = NULL; | |
113 | map->fmh = NULL; | |
7c8b597e | 114 | return git__throw(GIT_ERROR, "Failed to munmap. Could not unmap view of file"); |
79ca2edc RJ |
115 | } |
116 | map->data = NULL; | |
117 | } | |
118 | ||
119 | if (map->fmh) { | |
120 | if (!CloseHandle(map->fmh)) { | |
121 | /* errno = ? */ | |
122 | map->fmh = NULL; | |
7c8b597e | 123 | return git__throw(GIT_ERROR, "Failed to munmap. Could not close handle"); |
79ca2edc RJ |
124 | } |
125 | map->fmh = NULL; | |
126 | } | |
127 | ||
128 | return GIT_SUCCESS; | |
129 | } | |
130 | ||
131 |