cristy | 3ed852e | 2009-09-05 21:47:34 +0000 | [diff] [blame] | 1 | # MAGICK_FUNC_MMAP_FILEIO |
| 2 | # ------------ |
| 3 | AC_DEFUN([MAGICK_FUNC_MMAP_FILEIO], |
| 4 | [AC_CHECK_HEADERS(stdlib.h unistd.h) |
| 5 | AC_CHECK_FUNCS(getpagesize) |
| 6 | AC_CACHE_CHECK(for working mmap file i/o, magick_cv_func_mmap_fileio, |
| 7 | [AC_RUN_IFELSE([AC_LANG_SOURCE([AC_INCLUDES_DEFAULT] |
| 8 | [[/* malloc might have been renamed as rpl_malloc. */ |
| 9 | #undef malloc |
| 10 | |
| 11 | /* |
| 12 | This test is derived from GNU Autoconf's similar macro. |
| 13 | The purpose of this test is to verify that files may be memory |
| 14 | mapped, and that memory mapping and file I/O are coherent. |
| 15 | |
| 16 | The test creates a test file, memory maps the file, updates |
| 17 | the file using the memory map, and then reads the file using |
| 18 | file I/O to verify that the file contains the updates. |
| 19 | */ |
| 20 | |
| 21 | #include <fcntl.h> |
| 22 | #include <sys/mman.h> |
| 23 | |
| 24 | #if !STDC_HEADERS && !HAVE_STDLIB_H |
| 25 | char *malloc (); |
| 26 | #endif |
| 27 | |
| 28 | /* This mess was copied from the GNU getpagesize.h. */ |
| 29 | #if !HAVE_GETPAGESIZE |
| 30 | /* Assume that all systems that can run configure have sys/param.h. */ |
| 31 | # if !HAVE_SYS_PARAM_H |
| 32 | # define HAVE_SYS_PARAM_H 1 |
| 33 | # endif |
| 34 | |
| 35 | # ifdef _SC_PAGESIZE |
| 36 | # define getpagesize() sysconf(_SC_PAGESIZE) |
| 37 | # else /* no _SC_PAGESIZE */ |
| 38 | # if HAVE_SYS_PARAM_H |
| 39 | # include <sys/param.h> |
| 40 | # ifdef EXEC_PAGESIZE |
| 41 | # define getpagesize() EXEC_PAGESIZE |
| 42 | # else /* no EXEC_PAGESIZE */ |
| 43 | # ifdef NBPG |
| 44 | # define getpagesize() NBPG * CLSIZE |
| 45 | # ifndef CLSIZE |
| 46 | # define CLSIZE 1 |
| 47 | # endif /* no CLSIZE */ |
| 48 | # else /* no NBPG */ |
| 49 | # ifdef NBPC |
| 50 | # define getpagesize() NBPC |
| 51 | # else /* no NBPC */ |
| 52 | # ifdef PAGESIZE |
| 53 | # define getpagesize() PAGESIZE |
| 54 | # endif /* PAGESIZE */ |
| 55 | # endif /* no NBPC */ |
| 56 | # endif /* no NBPG */ |
| 57 | # endif /* no EXEC_PAGESIZE */ |
| 58 | # else /* no HAVE_SYS_PARAM_H */ |
| 59 | # define getpagesize() 8192 /* punt totally */ |
| 60 | # endif /* no HAVE_SYS_PARAM_H */ |
| 61 | # endif /* no _SC_PAGESIZE */ |
| 62 | |
| 63 | #endif /* no HAVE_GETPAGESIZE */ |
| 64 | |
| 65 | int |
| 66 | main () |
| 67 | { |
| 68 | char *data, *data2, *data3; |
| 69 | int i, pagesize; |
| 70 | int fd; |
| 71 | |
| 72 | pagesize = getpagesize (); |
| 73 | |
| 74 | /* First, make a file with some known garbage in it. */ |
| 75 | data = (char *) malloc (pagesize); |
| 76 | if (!data) |
| 77 | exit (1); |
| 78 | for (i = 0; i < pagesize; ++i) |
| 79 | *(data + i) = rand (); |
| 80 | umask (0); |
| 81 | fd = creat ("conftest.mmap", 0600); |
| 82 | if (fd < 0) |
| 83 | exit (1); |
| 84 | if (write (fd, data, pagesize) != pagesize) |
| 85 | exit (1); |
| 86 | close (fd); |
| 87 | |
| 88 | /* Mmap the file as read/write/shared and verify that we see the |
| 89 | same garbage. */ |
| 90 | fd = open ("conftest.mmap", O_RDWR); |
| 91 | if (fd < 0) |
| 92 | exit (1); |
| 93 | data2 = mmap (0, pagesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0L); |
| 94 | if (data2 == 0) |
| 95 | exit (1); |
| 96 | for (i = 0; i < pagesize; ++i) |
| 97 | if (*(data + i) != *(data2 + i)) |
| 98 | exit (1); |
| 99 | |
| 100 | /* Finally, make sure that changes to the mapped area |
| 101 | percolate back to the file as seen by read(). */ |
| 102 | for (i = 0; i < pagesize; ++i) |
| 103 | *(data2 + i) = *(data2 + i) + 1; |
| 104 | data3 = (char *) malloc (pagesize); |
| 105 | if (!data3) |
| 106 | exit (1); |
| 107 | if (read (fd, data3, pagesize) != pagesize) |
| 108 | exit (1); |
| 109 | for (i = 0; i < pagesize; ++i) |
| 110 | if (*(data2 + i) != *(data3 + i)) |
| 111 | exit (1); |
| 112 | close (fd); |
| 113 | exit (0); |
| 114 | }]])], |
| 115 | [magick_cv_func_mmap_fileio=yes], |
| 116 | [magick_cv_func_mmap_fileio=no], |
| 117 | [magick_cv_func_mmap_fileio=no])]) |
| 118 | if test $magick_cv_func_mmap_fileio = yes; then |
| 119 | AC_DEFINE(HAVE_MMAP_FILEIO, 1, |
| 120 | [Define to 1 if you have a working `mmap' system call.]) |
| 121 | fi |
| 122 | rm -f conftest.mmap |
| 123 | ])# MAGICK_FUNC_MMAP_FILEIO |