1 | /* ----------------------------------------------------------------------- * |
2 | * |
3 | * Copyright 1996-2017 The NASM Authors - All Rights Reserved |
4 | * See the file AUTHORS included with the NASM distribution for |
5 | * the specific copyright holders. |
6 | * |
7 | * Redistribution and use in source and binary forms, with or without |
8 | * modification, are permitted provided that the following |
9 | * conditions are met: |
10 | * |
11 | * * Redistributions of source code must retain the above copyright |
12 | * notice, this list of conditions and the following disclaimer. |
13 | * * Redistributions in binary form must reproduce the above |
14 | * copyright notice, this list of conditions and the following |
15 | * disclaimer in the documentation and/or other materials provided |
16 | * with the distribution. |
17 | * |
18 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND |
19 | * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
20 | * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
21 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
22 | * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
23 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
24 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
25 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
26 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
29 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, |
30 | * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
31 | * |
32 | * ----------------------------------------------------------------------- */ |
33 | |
34 | #include "file.h" |
35 | |
36 | /* ----------------------------------------------------------------------- * |
37 | * Unix-style memory mapping, using mmap(). |
38 | * ----------------------------------------------------------------------- */ |
39 | #if defined(HAVE_FILENO) && defined(HAVE_MMAP) |
40 | |
41 | /* |
42 | * System page size |
43 | */ |
44 | |
45 | /* File scope since not all compilers like static data in inline functions */ |
46 | static size_t nasm_pagemask; |
47 | |
48 | static size_t get_pagemask(void) |
49 | { |
50 | size_t ps = 0; |
51 | |
52 | # if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE) |
53 | ps = sysconf(_SC_PAGESIZE); |
54 | # elif defined(HAVE_GETPAGESIZE) |
55 | ps = getpagesize(); |
56 | # elif defined(PAGE_SIZE) |
57 | ps = PAGE_SIZE; |
58 | # endif |
59 | |
60 | nasm_pagemask = ps = is_power2(ps) ? (ps - 1) : 0; |
61 | return ps; |
62 | } |
63 | |
64 | static inline size_t pagemask(void) |
65 | { |
66 | size_t pm = nasm_pagemask; |
67 | |
68 | if (unlikely(!pm)) |
69 | return get_pagemask(); |
70 | |
71 | return pm; |
72 | } |
73 | |
74 | /* |
75 | * Try to map an input file into memory |
76 | */ |
77 | const void *nasm_map_file(FILE *fp, off_t start, off_t len) |
78 | { |
79 | const char *p; |
80 | off_t astart; /* Aligned start */ |
81 | size_t salign; /* Amount of start adjustment */ |
82 | size_t alen; /* Aligned length */ |
83 | const size_t page_mask = pagemask(); |
84 | |
85 | if (unlikely(!page_mask)) |
86 | return NULL; /* Page size undefined? */ |
87 | |
88 | if (unlikely(!len)) |
89 | return NULL; /* Mapping nothing... */ |
90 | |
91 | if (unlikely(len != (off_t)(size_t)len)) |
92 | return NULL; /* Address space insufficient */ |
93 | |
94 | astart = start & ~(off_t)page_mask; |
95 | salign = start - astart; |
96 | alen = (len + salign + page_mask) & ~page_mask; |
97 | |
98 | p = mmap(NULL, alen, PROT_READ, MAP_SHARED, fileno(fp), astart); |
99 | return unlikely(p == MAP_FAILED) ? NULL : p + salign; |
100 | } |
101 | |
102 | /* |
103 | * Unmap an input file |
104 | */ |
105 | void nasm_unmap_file(const void *p, size_t len) |
106 | { |
107 | const size_t page_mask = pagemask(); |
108 | uintptr_t astart; |
109 | size_t salign; |
110 | size_t alen; |
111 | |
112 | if (unlikely(!page_mask)) |
113 | return; |
114 | |
115 | astart = (uintptr_t)p & ~(uintptr_t)page_mask; |
116 | salign = (uintptr_t)p - astart; |
117 | alen = (len + salign + page_mask) & ~page_mask; |
118 | |
119 | munmap((void *)astart, alen); |
120 | } |
121 | |
122 | /* ----------------------------------------------------------------------- * |
123 | * No memory map support at all |
124 | * XXX: Add a section with Windows support |
125 | * ----------------------------------------------------------------------- */ |
126 | #else |
127 | |
128 | const void *nasm_map_file(FILE *fp, off_t start, off_t len) |
129 | { |
130 | (void)fp; (void)start; (void)len; |
131 | return NULL; |
132 | } |
133 | |
134 | void nasm_unmap_file(const void *p, size_t len) |
135 | { |
136 | (void)p; (void)len; |
137 | } |
138 | |
139 | #endif |
140 | |