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5196736e AJ |
1 | # mmap(2) blacklisting. Some platforms provide the mmap library routine |
2 | # but don't support all of the features we need from it. | |
3 | AC_DEFUN([AC_FUNC_MMAP_BLACKLIST], | |
4d447364 MR |
4 | [ |
5 | AC_CHECK_HEADER([sys/mman.h], | |
6 | [libffi_header_sys_mman_h=yes], [libffi_header_sys_mman_h=no]) | |
7 | AC_CHECK_FUNC([mmap], [libffi_func_mmap=yes], [libffi_func_mmap=no]) | |
8 | if test "$libffi_header_sys_mman_h" != yes \ | |
9 | || test "$libffi_func_mmap" != yes; then | |
5196736e AJ |
10 | ac_cv_func_mmap_file=no |
11 | ac_cv_func_mmap_dev_zero=no | |
12 | ac_cv_func_mmap_anon=no | |
13 | else | |
14 | AC_CACHE_CHECK([whether read-only mmap of a plain file works], | |
15 | ac_cv_func_mmap_file, | |
16 | [# Add a system to this blacklist if | |
17 | # mmap(0, stat_size, PROT_READ, MAP_PRIVATE, fd, 0) doesn't return a | |
18 | # memory area containing the same data that you'd get if you applied | |
19 | # read() to the same fd. The only system known to have a problem here | |
20 | # is VMS, where text files have record structure. | |
21 | case "$host_os" in | |
22 | vms* | ultrix*) | |
23 | ac_cv_func_mmap_file=no ;; | |
24 | *) | |
25 | ac_cv_func_mmap_file=yes;; | |
26 | esac]) | |
27 | AC_CACHE_CHECK([whether mmap from /dev/zero works], | |
28 | ac_cv_func_mmap_dev_zero, | |
29 | [# Add a system to this blacklist if it has mmap() but /dev/zero | |
30 | # does not exist, or if mmapping /dev/zero does not give anonymous | |
31 | # zeroed pages with both the following properties: | |
32 | # 1. If you map N consecutive pages in with one call, and then | |
33 | # unmap any subset of those pages, the pages that were not | |
34 | # explicitly unmapped remain accessible. | |
35 | # 2. If you map two adjacent blocks of memory and then unmap them | |
36 | # both at once, they must both go away. | |
37 | # Systems known to be in this category are Windows (all variants), | |
38 | # VMS, and Darwin. | |
39 | case "$host_os" in | |
40 | vms* | cygwin* | pe | mingw* | darwin* | ultrix* | hpux10* | hpux11.00) | |
41 | ac_cv_func_mmap_dev_zero=no ;; | |
42 | *) | |
43 | ac_cv_func_mmap_dev_zero=yes;; | |
44 | esac]) | |
45 | ||
46 | # Unlike /dev/zero, the MAP_ANON(YMOUS) defines can be probed for. | |
47 | AC_CACHE_CHECK([for MAP_ANON(YMOUS)], ac_cv_decl_map_anon, | |
48 | [AC_TRY_COMPILE( | |
49 | [#include <sys/types.h> | |
50 | #include <sys/mman.h> | |
51 | #include <unistd.h> | |
52 | ||
53 | #ifndef MAP_ANONYMOUS | |
54 | #define MAP_ANONYMOUS MAP_ANON | |
55 | #endif | |
56 | ], | |
57 | [int n = MAP_ANONYMOUS;], | |
58 | ac_cv_decl_map_anon=yes, | |
59 | ac_cv_decl_map_anon=no)]) | |
60 | ||
61 | if test $ac_cv_decl_map_anon = no; then | |
62 | ac_cv_func_mmap_anon=no | |
63 | else | |
64 | AC_CACHE_CHECK([whether mmap with MAP_ANON(YMOUS) works], | |
65 | ac_cv_func_mmap_anon, | |
66 | [# Add a system to this blacklist if it has mmap() and MAP_ANON or | |
67 | # MAP_ANONYMOUS, but using mmap(..., MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) | |
68 | # doesn't give anonymous zeroed pages with the same properties listed | |
69 | # above for use of /dev/zero. | |
70 | # Systems known to be in this category are Windows, VMS, and SCO Unix. | |
71 | case "$host_os" in | |
72 | vms* | cygwin* | pe | mingw* | sco* | udk* ) | |
73 | ac_cv_func_mmap_anon=no ;; | |
74 | *) | |
75 | ac_cv_func_mmap_anon=yes;; | |
76 | esac]) | |
77 | fi | |
78 | fi | |
79 | ||
80 | if test $ac_cv_func_mmap_file = yes; then | |
81 | AC_DEFINE(HAVE_MMAP_FILE, 1, | |
82 | [Define if read-only mmap of a plain file works.]) | |
83 | fi | |
84 | if test $ac_cv_func_mmap_dev_zero = yes; then | |
85 | AC_DEFINE(HAVE_MMAP_DEV_ZERO, 1, | |
86 | [Define if mmap of /dev/zero works.]) | |
87 | fi | |
88 | if test $ac_cv_func_mmap_anon = yes; then | |
89 | AC_DEFINE(HAVE_MMAP_ANON, 1, | |
90 | [Define if mmap with MAP_ANON(YMOUS) works.]) | |
91 | fi | |
92 | ]) |