X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Flink-follow.m4;h=3f1127aa62f64979fe0673fdbaca5f532262d947;hb=279067b9021cfd0935711cae3f3297ae4b3808af;hp=eb98c3b62b8aca2a614e181a2d70f40c64e6caaf;hpb=ee67d8ea6bd183f5ce32d90a6764705d766c3d6b;p=gnulib.git

diff --git a/m4/link-follow.m4 b/m4/link-follow.m4
index eb98c3b62..3f1127aa6 100644
--- a/m4/link-follow.m4
+++ b/m4/link-follow.m4
@@ -1,8 +1,8 @@
-# serial 13
+# serial 16
 dnl Run a program to determine whether link(2) follows symlinks.
 dnl Set LINK_FOLLOWS_SYMLINKS accordingly.
 
-# Copyright (C) 1999-2001, 2004-2006, 2009 Free Software Foundation, Inc.
+# Copyright (C) 1999-2001, 2004-2006, 2009-2011 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
@@ -12,7 +12,8 @@ dnl LINK_FOLLOWS_SYMLINKS is 0, link matches linkat(,0), and
 dnl linkat(,AT_SYMLINK_FOLLOW) requires a readlink. If it is 1,
 dnl link matches linkat(,AT_SYMLINK_FOLLOW), and there is no way
 dnl to do linkat(,0) on symlinks (on all other file types,
-dnl link() is sufficient).  If it is -1, use a runtime test.
+dnl link() is sufficient).  If it is -1, use a Solaris specific
+dnl runtime test.  If it is -2, use a generic runtime test.
 AC_DEFUN([gl_FUNC_LINK_FOLLOWS_SYMLINK],
 [dnl
   AC_CHECK_FUNCS_ONCE([readlink])
@@ -22,59 +23,77 @@ AC_DEFUN([gl_FUNC_LINK_FOLLOWS_SYMLINK],
   dnl linkat variants.  So, we set LINK_FOLLOWS_SYMLINKS to 0.
   gl_link_follows_symlinks=0 # assume GNU behavior
   if test $ac_cv_func_readlink = yes; then
-    AC_CACHE_CHECK([whether link(2) dereferences a symlink],
-		    gl_cv_func_link_follows_symlink,
-    [
-      # Create a regular file.
-      echo > conftest.file
-      AC_RUN_IFELSE([AC_LANG_SOURCE([[
+    dnl Solaris has an __xpg4 variable in libc, and it determines the
+    dnl behaviour of link(): It dereferences a symlink if and only if
+    dnl __xpg4 != 0.
+    AC_CACHE_CHECK([for __xpg4], [gl_cv_have___xpg4],
+      [AC_LINK_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[extern int __xpg4;]],
+            [[return __xpg4;]])],
+         [gl_cv_have___xpg4=yes],
+         [gl_cv_have___xpg4=no])
+      ])
+    if test $gl_cv_have___xpg4 = yes; then
+      gl_link_follows_symlinks=-1
+    else
+      AC_CACHE_CHECK([whether link(2) dereferences a symlink],
+                     [gl_cv_func_link_follows_symlink],
+        [
+         # Create a regular file.
+         echo > conftest.file
+         AC_RUN_IFELSE(
+           [AC_LANG_SOURCE([[
 #       include <sys/types.h>
 #       include <sys/stat.h>
 #       include <unistd.h>
 #       include <stdlib.h>
 
 #       define SAME_INODE(Stat_buf_1, Stat_buf_2) \
-	  ((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
-	   && (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
+          ((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
+           && (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
 
-	int
-	main ()
-	{
-	  const char *file = "conftest.file";
-	  const char *sym = "conftest.sym";
-	  const char *hard = "conftest.hard";
-	  struct stat sb_file, sb_hard;
+        int
+        main ()
+        {
+          const char *file = "conftest.file";
+          const char *sym = "conftest.sym";
+          const char *hard = "conftest.hard";
+          struct stat sb_file, sb_hard;
 
-	  /* Create a symlink to the regular file. */
-	  if (symlink (file, sym))
-	    abort ();
+          /* Create a symlink to the regular file. */
+          if (symlink (file, sym))
+            return 2;
 
-	  /* Create a hard link to that symlink.  */
-	  if (link (sym, hard))
-	    abort ();
+          /* Create a hard link to that symlink.  */
+          if (link (sym, hard))
+            return 3;
 
-	  if (lstat (hard, &sb_hard))
-	    abort ();
-	  if (lstat (file, &sb_file))
-	    abort ();
+          if (lstat (hard, &sb_hard))
+            return 4;
+          if (lstat (file, &sb_file))
+            return 5;
 
-	  /* If the dev/inode of hard and file are the same, then
-	     the link call followed the symlink.  */
-	  return SAME_INODE (sb_hard, sb_file) ? 0 : 1;
-	}
-      ]])],
-	[gl_cv_func_link_follows_symlink=yes],
-	[gl_cv_func_link_follows_symlink=no],
-	[gl_cv_func_link_follows_symlink=unknown] dnl We're cross compiling.
-      )
-    ])
-    case $gl_cv_func_link_follows_symlink in
-      yes) ;;
-      no) gl_link_follows_symlinks=1 ;;
-      *) gl_link_follows_symlinks=-1 ;;
-    esac
+          /* If the dev/inode of hard and file are the same, then
+             the link call followed the symlink.  */
+          return SAME_INODE (sb_hard, sb_file) ? 1 : 0;
+        }
+           ]])],
+           [gl_cv_func_link_follows_symlink=no], dnl GNU behavior
+           [gl_cv_func_link_follows_symlink=yes], dnl Followed link/compile failed
+           [gl_cv_func_link_follows_symlink=unknown] dnl We're cross compiling.
+         )
+         rm -f conftest.file conftest.sym conftest.hard
+        ])
+      case $gl_cv_func_link_follows_symlink in
+        yes) gl_link_follows_symlinks=1 ;;
+        no) ;; # already defaulted to 0
+        *) gl_link_follows_symlinks=-2 ;;
+      esac
+    fi
   fi
   AC_DEFINE_UNQUOTED([LINK_FOLLOWS_SYMLINKS], [$gl_link_follows_symlinks],
     [Define to 1 if `link(2)' dereferences symbolic links, 0 if it
-     creates hard links to symlinks, and -1 if unknown.])
+     creates hard links to symlinks, -1 if it depends on the variable __xpg4,
+     and -2 if unknown.])
 ])