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Re: configure check for sys/mman.h


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Am Dienstag, 21. Januar 2003 22:05 schrieb Tom Tromey:
> >>>>> "Michael" == Michael Koch <konqueror@gmx.de> writes:
>
> Michael> Is this patch not good enough for review ?
> Michael> (or too complicated ;-))
>
> No, I'm just behind.
>
> I wonder if those checks will be enough.  Historically there have
> been lots of configury problems with mmap().  If we fall back to
> something sensible on mmap failure, then it won't matter too much.

I've digged a little bit more and found a "better" solution using an 
autoconf feature. Please review and comment on this.

We will need mmap very soon now for java.nio.


Michael
- -- 
Homepage: http://www.worldforge.org/
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Index: ChangeLog
===================================================================
RCS file: /cvs/gcc/gcc/libjava/ChangeLog,v
retrieving revision 1.1715
diff -u -r1.1715 ChangeLog
--- ChangeLog	18 Feb 2003 07:26:20 -0000	1.1715
+++ ChangeLog	18 Feb 2003 16:03:07 -0000
@@ -1,5 +1,11 @@
 2003-02-18  Michael Koch  <konqueror@gmx.de>
 
+	* configure.in: Added check for memory mapping of files.
+	* configure: Regenerated.
+	* config.h.in: Regenerated.
+
+2003-02-18  Michael Koch  <konqueror@gmx.de>
+
 	* java/nio/channels/FileChannel.java
 	(toString): New implementation, added documentation.
 	(map): Added exception documentation.
Index: configure
===================================================================
RCS file: /cvs/gcc/gcc/libjava/configure,v
retrieving revision 1.168
diff -u -r1.168 configure
--- configure	13 Feb 2003 02:51:26 -0000	1.168
+++ configure	18 Feb 2003 16:03:11 -0000
@@ -8260,6 +8260,272 @@
 
 fi
 
+for ac_hdr in unistd.h
+do
+ac_safe=`echo "$ac_hdr" | sed 'y%./+-%__p_%'`
+echo $ac_n "checking for $ac_hdr""... $ac_c" 1>&6
+echo "configure:8268: checking for $ac_hdr" >&5
+if eval "test \"`echo '$''{'ac_cv_header_$ac_safe'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+  cat > conftest.$ac_ext <<EOF
+#line 8273 "configure"
+#include "confdefs.h"
+#include <$ac_hdr>
+EOF
+ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
+{ (eval echo configure:8278: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
+ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
+if test -z "$ac_err"; then
+  rm -rf conftest*
+  eval "ac_cv_header_$ac_safe=yes"
+else
+  echo "$ac_err" >&5
+  echo "configure: failed program was:" >&5
+  cat conftest.$ac_ext >&5
+  rm -rf conftest*
+  eval "ac_cv_header_$ac_safe=no"
+fi
+rm -f conftest*
+fi
+if eval "test \"`echo '$ac_cv_header_'$ac_safe`\" = yes"; then
+  echo "$ac_t""yes" 1>&6
+    ac_tr_hdr=HAVE_`echo $ac_hdr | sed 'y%abcdefghijklmnopqrstuvwxyz./-%ABCDEFGHIJKLMNOPQRSTUVWXYZ___%'`
+  cat >> confdefs.h <<EOF
+#define $ac_tr_hdr 1
+EOF
+ 
+else
+  echo "$ac_t""no" 1>&6
+fi
+done
+
+for ac_func in getpagesize
+do
+echo $ac_n "checking for $ac_func""... $ac_c" 1>&6
+echo "configure:8307: checking for $ac_func" >&5
+if eval "test \"`echo '$''{'ac_cv_func_$ac_func'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+  cat > conftest.$ac_ext <<EOF
+#line 8312 "configure"
+#include "confdefs.h"
+/* System header to define __stub macros and hopefully few prototypes,
+    which can conflict with char $ac_func(); below.  */
+#include <assert.h>
+/* Override any gcc2 internal prototype to avoid an error.  */
+/* We use char because int might match the return type of a gcc2
+    builtin and then its argument prototype would still apply.  */
+char $ac_func();
+
+int main() {
+
+/* The GNU C library defines this for functions which it implements
+    to always fail with ENOSYS.  Some functions are actually named
+    something starting with __ and the normal name is an alias.  */
+#if defined (__stub_$ac_func) || defined (__stub___$ac_func)
+choke me
+#else
+$ac_func();
+#endif
+
+; return 0; }
+EOF
+if { (eval echo configure:8335: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+  rm -rf conftest*
+  eval "ac_cv_func_$ac_func=yes"
+else
+  echo "configure: failed program was:" >&5
+  cat conftest.$ac_ext >&5
+  rm -rf conftest*
+  eval "ac_cv_func_$ac_func=no"
+fi
+rm -f conftest*
+fi
+
+if eval "test \"`echo '$ac_cv_func_'$ac_func`\" = yes"; then
+  echo "$ac_t""yes" 1>&6
+    ac_tr_func=HAVE_`echo $ac_func | tr 'abcdefghijklmnopqrstuvwxyz' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'`
+  cat >> confdefs.h <<EOF
+#define $ac_tr_func 1
+EOF
+ 
+else
+  echo "$ac_t""no" 1>&6
+fi
+done
+
+echo $ac_n "checking for working mmap""... $ac_c" 1>&6
+echo "configure:8360: checking for working mmap" >&5
+if eval "test \"`echo '$''{'ac_cv_func_mmap_fixed_mapped'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+  if test "$cross_compiling" = yes; then
+  ac_cv_func_mmap_fixed_mapped=no
+else
+  cat > conftest.$ac_ext <<EOF
+#line 8368 "configure"
+#include "confdefs.h"
+
+/* Thanks to Mike Haertel and Jim Avera for this test.
+   Here is a matrix of mmap possibilities:
+	mmap private not fixed
+	mmap private fixed at somewhere currently unmapped
+	mmap private fixed at somewhere already mapped
+	mmap shared not fixed
+	mmap shared fixed at somewhere currently unmapped
+	mmap shared fixed at somewhere already mapped
+   For private mappings, we should verify that changes cannot be read()
+   back from the file, nor mmap's back from the file at a different
+   address.  (There have been systems where private was not correctly
+   implemented like the infamous i386 svr4.0, and systems where the
+   VM page cache was not coherent with the filesystem buffer cache
+   like early versions of FreeBSD and possibly contemporary NetBSD.)
+   For shared mappings, we should conversely verify that changes get
+   propogated back to all the places they're supposed to be.
+
+   Grep wants private fixed already mapped.
+   The main things grep needs to know about mmap are:
+   * does it exist and is it safe to write into the mmap'd area
+   * how to use it (BSD variants)  */
+#include <sys/types.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+/* This mess was copied from the GNU getpagesize.h.  */
+#ifndef HAVE_GETPAGESIZE
+# ifdef HAVE_UNISTD_H
+#  include <unistd.h>
+# endif
+
+/* Assume that all systems that can run configure have sys/param.h.  */
+# ifndef HAVE_SYS_PARAM_H
+#  define HAVE_SYS_PARAM_H 1
+# endif
+
+# ifdef _SC_PAGESIZE
+#  define getpagesize() sysconf(_SC_PAGESIZE)
+# else /* no _SC_PAGESIZE */
+#  ifdef HAVE_SYS_PARAM_H
+#   include <sys/param.h>
+#   ifdef EXEC_PAGESIZE
+#    define getpagesize() EXEC_PAGESIZE
+#   else /* no EXEC_PAGESIZE */
+#    ifdef NBPG
+#     define getpagesize() NBPG * CLSIZE
+#     ifndef CLSIZE
+#      define CLSIZE 1
+#     endif /* no CLSIZE */
+#    else /* no NBPG */
+#     ifdef NBPC
+#      define getpagesize() NBPC
+#     else /* no NBPC */
+#      ifdef PAGESIZE
+#       define getpagesize() PAGESIZE
+#      endif /* PAGESIZE */
+#     endif /* no NBPC */
+#    endif /* no NBPG */
+#   endif /* no EXEC_PAGESIZE */
+#  else /* no HAVE_SYS_PARAM_H */
+#   define getpagesize() 8192	/* punt totally */
+#  endif /* no HAVE_SYS_PARAM_H */
+# endif /* no _SC_PAGESIZE */
+
+#endif /* no HAVE_GETPAGESIZE */
+
+#ifdef __cplusplus
+extern "C" { void *malloc(unsigned); }
+#else
+char *malloc();
+#endif
+
+int
+main()
+{
+	char *data, *data2, *data3;
+	int i, pagesize;
+	int fd;
+
+	pagesize = getpagesize();
+
+	/*
+	 * First, make a file with some known garbage in it.
+	 */
+	data = malloc(pagesize);
+	if (!data)
+		exit(1);
+	for (i = 0; i < pagesize; ++i)
+		*(data + i) = rand();
+	umask(0);
+	fd = creat("conftestmmap", 0600);
+	if (fd < 0)
+		exit(1);
+	if (write(fd, data, pagesize) != pagesize)
+		exit(1);
+	close(fd);
+
+	/*
+	 * Next, try to mmap the file at a fixed address which
+	 * already has something else allocated at it.  If we can,
+	 * also make sure that we see the same garbage.
+	 */
+	fd = open("conftestmmap", O_RDWR);
+	if (fd < 0)
+		exit(1);
+	data2 = malloc(2 * pagesize);
+	if (!data2)
+		exit(1);
+	data2 += (pagesize - ((int) data2 & (pagesize - 1))) & (pagesize - 1);
+	if (data2 != mmap(data2, pagesize, PROT_READ | PROT_WRITE,
+	    MAP_PRIVATE | MAP_FIXED, fd, 0L))
+		exit(1);
+	for (i = 0; i < pagesize; ++i)
+		if (*(data + i) != *(data2 + i))
+			exit(1);
+
+	/*
+	 * Finally, make sure that changes to the mapped area
+	 * do not percolate back to the file as seen by read().
+	 * (This is a bug on some variants of i386 svr4.0.)
+	 */
+	for (i = 0; i < pagesize; ++i)
+		*(data2 + i) = *(data2 + i) + 1;
+	data3 = malloc(pagesize);
+	if (!data3)
+		exit(1);
+	if (read(fd, data3, pagesize) != pagesize)
+		exit(1);
+	for (i = 0; i < pagesize; ++i)
+		if (*(data + i) != *(data3 + i))
+			exit(1);
+	close(fd);
+	unlink("conftestmmap");
+	exit(0);
+}
+
+EOF
+if { (eval echo configure:8508: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext} && (./conftest; exit) 2>/dev/null
+then
+  ac_cv_func_mmap_fixed_mapped=yes
+else
+  echo "configure: failed program was:" >&5
+  cat conftest.$ac_ext >&5
+  rm -fr conftest*
+  ac_cv_func_mmap_fixed_mapped=no
+fi
+rm -fr conftest*
+fi
+
+fi
+
+echo "$ac_t""$ac_cv_func_mmap_fixed_mapped" 1>&6
+if test $ac_cv_func_mmap_fixed_mapped = yes; then
+  cat >> confdefs.h <<\EOF
+#define HAVE_MMAP 1
+EOF
+
+fi
+
 
 for ac_prog in perl
 do
Index: configure.in
===================================================================
RCS file: /cvs/gcc/gcc/libjava/configure.in,v
retrieving revision 1.150
diff -u -r1.150 configure.in
--- configure.in	13 Feb 2003 02:51:26 -0000	1.150
+++ configure.in	18 Feb 2003 16:03:11 -0000
@@ -970,6 +970,7 @@
           [AC_MSG_RESULT(no)])])])
 
 AC_FUNC_ALLOCA
+AC_FUNC_MMAP
 
 AC_CHECK_PROGS(PERL, perl, false)
 
Index: include/config.h.in
===================================================================
RCS file: /cvs/gcc/gcc/libjava/include/config.h.in,v
retrieving revision 1.47
diff -u -r1.47 config.h.in
--- include/config.h.in	31 Jan 2003 17:59:00 -0000	1.47
+++ include/config.h.in	18 Feb 2003 16:03:11 -0000
@@ -13,6 +13,9 @@
 /* Define if you have <alloca.h> and it should be used (not on Ultrix).  */
 #undef HAVE_ALLOCA_H
 
+/* Define if you have a working `mmap' system call.  */
+#undef HAVE_MMAP
+
 /* Define if you have <sys/wait.h> that is POSIX.1 compatible.  */
 #undef HAVE_SYS_WAIT_H
 
@@ -216,6 +219,9 @@
 
 /* Define if you have the gethostname function.  */
 #undef HAVE_GETHOSTNAME
+
+/* Define if you have the getpagesize function.  */
+#undef HAVE_GETPAGESIZE
 
 /* Define if you have the getpwuid_r function.  */
 #undef HAVE_GETPWUID_R

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