* aclocal.m4: New file with new test libiberty_AC_FUNC_STRNCMP.

	* configure.in (AC_CHECK_HEADERS): Add sys/mman.h fcntl.h.
	(libiberty_AC_FUNC_STRNCMP): Invoke.

	* strncmp.c: New file.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@33498 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 71 insertions, 0 deletions

diff --git a/libiberty/aclocal.m4 b/libiberty/aclocal.m4
new file mode 100644
index 00000000000..b6a38d60522
--- /dev/null
+++ b/libiberty/aclocal.m4
@@ -0,0 +1,71 @@
+dnl See whether strncmp reads past the end of its string parameters.
+dnl On some versions of SunOS4 at least, strncmp reads a word at a time
+dnl but erroneously reads past the end of strings.  This can cause
+dnl a SEGV in some cases.
+AC_DEFUN(libiberty_AC_FUNC_STRNCMP,
+[AC_REQUIRE([AC_FUNC_MMAP])
+AC_CACHE_CHECK([for working strncmp], ac_cv_func_strncmp_works,
+[AC_TRY_RUN([
+/* Test by Jim Wilson and Kaveh Ghazi.
+   Check whether strncmp reads past the end of its string parameters. */
+#include <sys/types.h>
+
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
+#ifndef MAP_ANON
+#ifdef MAP_ANONYMOUS
+#define MAP_ANON MAP_ANONYMOUS
+#else
+#define MAP_ANON MAP_FILE
+#endif
+#endif
+
+#ifndef MAP_FILE
+#define MAP_FILE 0
+#endif
+#ifndef O_RDONLY
+#define O_RDONLY 0
+#endif
+
+#define MAP_LEN 0x10000
+
+main ()
+{
+#if defined(HAVE_MMAP) || defined(HAVE_MMAP_ANYWHERE)
+  char *p;
+  int dev_zero;
+
+  dev_zero = open ("/dev/zero", O_RDONLY);
+  if (dev_zero < 0)
+    exit (1);
+  
+  p = (char *) mmap (0, MAP_LEN, PROT_READ|PROT_WRITE,
+		     MAP_ANON|MAP_PRIVATE, dev_zero, 0);
+  if (p == (char *)-1)
+    exit (2);
+  else
+    {
+      char *string = "__si_type_info";
+      char *q = (char *) p + MAP_LEN - strlen (string) - 2;
+      char *r = (char *) p + 0xe;
+
+      strcpy (q, string);
+      strcpy (r, string);
+      strncmp (r, q, 14);
+    }
+#endif /* HAVE_MMAP || HAVE_MMAP_ANYWHERE */
+  exit (0);
+}
+], ac_cv_func_strncmp_works=yes, ac_cv_func_strncmp_works=no,
+  ac_cv_func_strncmp_works=no)
+rm -f core core.* *.core])
+if test $ac_cv_func_strncmp_works = no ; then
+  LIBOBJS="$LIBOBJS strncmp.o"
+fi
+])