aclocal.m4: New file with new test libiberty_AC_FUNC_STRNCMP.

	* 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.

From-SVN: r33498

libiberty/ChangeLog

+2000-04-27  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* 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.
+
 Thu Apr 27 16:58:43 MET DST 2000  Jan Hubicka  <jh@suse.cz>
 
 	* hashtab.c (htab_expand): Add prototype.

libiberty/aclocal.m4

+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
+])

libiberty/config.in

@@ -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
 
@@ -196,6 +199,9 @@
 /* Define if you have the waitpid function.  */
 #undef HAVE_WAITPID
 
+/* Define if you have the <fcntl.h> header file.  */
+#undef HAVE_FCNTL_H
+
 /* Define if you have the <stdlib.h> header file.  */
 #undef HAVE_STDLIB_H
 
@@ -208,6 +214,9 @@
 /* Define if you have the <sys/file.h> header file.  */
 #undef HAVE_SYS_FILE_H
 
+/* Define if you have the <sys/mman.h> header file.  */
+#undef HAVE_SYS_MMAN_H
+
 /* Define if you have the <sys/param.h> header file.  */
 #undef HAVE_SYS_PARAM_H
 

libiberty/configure.in

@@ -109,7 +109,7 @@ AC_SUBST_FILE(host_makefile_frag)
 # It's OK to check for header files.  Although the compiler may not be
 # able to link anything, it had better be able to at least compile
 # something.
-AC_CHECK_HEADERS(sys/file.h sys/param.h stdlib.h string.h unistd.h strings.h sys/time.h sys/resource.h sys/stat.h)
+AC_CHECK_HEADERS(sys/file.h sys/param.h stdlib.h string.h unistd.h strings.h sys/time.h sys/resource.h sys/stat.h sys/mman.h fcntl.h)
 AC_HEADER_SYS_WAIT
 
 # This is the list of functions which libiberty will provide if they
@@ -352,6 +352,8 @@ EOF
   AC_CHECK_FUNCS($checkfuncs)
 fi
 
+libiberty_AC_FUNC_STRNCMP
+
 # Install a library built with a cross compiler in $(tooldir) rather
 # than $(libdir).
 if test -z "${with_cross_host}"; then

libiberty/strncmp.c

+/* strncmp -- compare two strings, stop after n bytes.
+   This function is in the public domain.  */
+
+#include <ansidecl.h>
+#ifdef __STDC__
+#include <stddef.h>
+#else
+#define size_t unsigned long
+#endif
+
+int
+strncmp(s1, s2, n)
+     const char *s1, *s2;
+     register size_t n;
+{
+  register unsigned char u1, u2;
+
+  while (n-- > 0)
+    {
+      u1 = (unsigned char) *s1++;
+      u2 = (unsigned char) *s2++;
+      if (u1 != u2)
+	return u1 - u2;
+      if (u1 == '\0')
+	return 0;
+    }
+  return 0;
+}