123 lines
3.3 KiB
Text
123 lines
3.3 KiB
Text
# MAGICK_FUNC_MMAP_FILEIO
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# ------------
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AC_DEFUN([MAGICK_FUNC_MMAP_FILEIO],
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[AC_CHECK_HEADERS(stdlib.h unistd.h)
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AC_CHECK_FUNCS(getpagesize)
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AC_CACHE_CHECK(for working mmap file i/o, magick_cv_func_mmap_fileio,
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[AC_RUN_IFELSE([AC_LANG_SOURCE([AC_INCLUDES_DEFAULT]
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[[/* malloc might have been renamed as rpl_malloc. */
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#undef malloc
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/*
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This test is derived from GNU Autoconf's similar macro.
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The purpose of this test is to verify that files may be memory
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mapped, and that memory mapping and file I/O are coherent.
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The test creates a test file, memory maps the file, updates
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the file using the memory map, and then reads the file using
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file I/O to verify that the file contains the updates.
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*/
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#include <fcntl.h>
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#include <sys/mman.h>
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#if !STDC_HEADERS && !HAVE_STDLIB_H
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char *malloc ();
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#endif
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/* This mess was copied from the GNU getpagesize.h. */
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#if !HAVE_GETPAGESIZE
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/* Assume that all systems that can run configure have sys/param.h. */
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# if !HAVE_SYS_PARAM_H
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# define HAVE_SYS_PARAM_H 1
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# endif
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# ifdef _SC_PAGESIZE
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# define getpagesize() sysconf(_SC_PAGESIZE)
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# else /* no _SC_PAGESIZE */
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# if HAVE_SYS_PARAM_H
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# include <sys/param.h>
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# ifdef EXEC_PAGESIZE
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# define getpagesize() EXEC_PAGESIZE
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# else /* no EXEC_PAGESIZE */
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# ifdef NBPG
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# define getpagesize() NBPG * CLSIZE
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# ifndef CLSIZE
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# define CLSIZE 1
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# endif /* no CLSIZE */
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# else /* no NBPG */
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# ifdef NBPC
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# define getpagesize() NBPC
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# else /* no NBPC */
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# ifdef PAGESIZE
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# define getpagesize() PAGESIZE
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# endif /* PAGESIZE */
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# endif /* no NBPC */
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# endif /* no NBPG */
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# endif /* no EXEC_PAGESIZE */
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# else /* no HAVE_SYS_PARAM_H */
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# define getpagesize() 8192 /* punt totally */
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# endif /* no HAVE_SYS_PARAM_H */
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# endif /* no _SC_PAGESIZE */
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#endif /* no HAVE_GETPAGESIZE */
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int
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main ()
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{
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char *data, *data2, *data3;
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int i, pagesize;
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int fd;
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pagesize = getpagesize ();
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/* First, make a file with some known garbage in it. */
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data = (char *) malloc (pagesize);
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if (!data)
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exit (1);
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for (i = 0; i < pagesize; ++i)
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*(data + i) = rand ();
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umask (0);
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fd = creat ("conftest.mmap", 0600);
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if (fd < 0)
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exit (1);
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if (write (fd, data, pagesize) != pagesize)
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exit (1);
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close (fd);
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/* Mmap the file as read/write/shared and verify that we see the
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same garbage. */
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fd = open ("conftest.mmap", O_RDWR);
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if (fd < 0)
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exit (1);
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data2 = mmap (0, pagesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0L);
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if (data2 == 0)
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exit (1);
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for (i = 0; i < pagesize; ++i)
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if (*(data + i) != *(data2 + i))
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exit (1);
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/* Finally, make sure that changes to the mapped area
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percolate back to the file as seen by read(). */
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for (i = 0; i < pagesize; ++i)
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*(data2 + i) = *(data2 + i) + 1;
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data3 = (char *) malloc (pagesize);
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if (!data3)
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exit (1);
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if (read (fd, data3, pagesize) != pagesize)
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exit (1);
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for (i = 0; i < pagesize; ++i)
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if (*(data2 + i) != *(data3 + i))
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exit (1);
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close (fd);
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exit (0);
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}]])],
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[magick_cv_func_mmap_fileio=yes],
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[magick_cv_func_mmap_fileio=no],
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[magick_cv_func_mmap_fileio=no])])
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if test $magick_cv_func_mmap_fileio = yes; then
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AC_DEFINE(HAVE_MMAP_FILEIO, 1,
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[Define to 1 if you have a working `mmap' system call.])
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fi
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rm -f conftest.mmap
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])# MAGICK_FUNC_MMAP_FILEIO
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