Import upstream version 1.27

[debian/tar] / m4 / dup2.m4

diff --git a/m4/dup2.m4 b/m4/dup2.m4
index def263b87a85b7ccd38e0c539f894718817a75c9..269cfdc112380f35982e67535be4b179a1d55e1f 100644 (file)
--- a/m4/dup2.m4
+++ b/m4/dup2.m4
@@ -1,5 +1,5 @@
-#serial 12
-dnl Copyright (C) 2002, 2005, 2007, 2009-2011 Free Software Foundation, Inc.
+#serial 19
+dnl Copyright (C) 2002, 2005, 2007, 2009-2013 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -8,24 +8,28 @@ AC_DEFUN([gl_FUNC_DUP2],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST])
-  AC_CHECK_FUNCS_ONCE([dup2 fcntl])
-  if test $ac_cv_func_dup2 = no; then
-    HAVE_DUP2=0
-    AC_LIBOBJ([dup2])
-  else
+  m4_ifdef([gl_FUNC_DUP2_OBSOLETE], [
+    AC_CHECK_FUNCS_ONCE([dup2])
+    if test $ac_cv_func_dup2 = no; then
+      HAVE_DUP2=0
+    fi
+  ], [
+    AC_DEFINE([HAVE_DUP2], [1], [Define to 1 if you have the 'dup2' function.])
+  ])
+  if test $HAVE_DUP2 = 1; then
     AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
       [AC_RUN_IFELSE([
          AC_LANG_PROGRAM([[#include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>]],
            [int result = 0;
-#if HAVE_FCNTL
+#ifdef FD_CLOEXEC
             if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
               result |= 1;
-#endif HAVE_FCNTL
+#endif
             if (dup2 (1, 1) == 0)
               result |= 2;
-#if HAVE_FCNTL
+#ifdef FD_CLOEXEC
             if (fcntl (1, F_GETFD) != FD_CLOEXEC)
               result |= 4;
 #endif
@@ -35,36 +39,46 @@ AC_DEFUN([gl_FUNC_DUP2],
             /* Many gnulib modules require POSIX conformance of EBADF.  */
             if (dup2 (2, 1000000) == -1 && errno != EBADF)
               result |= 16;
+            /* Flush out a cygwin core dump.  */
+            if (dup2 (2, -1) != -1 || errno != EBADF)
+              result |= 32;
             return result;
            ])
         ],
         [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
         [case "$host_os" in
            mingw*) # on this platform, dup2 always returns 0 for success
-             gl_cv_func_dup2_works=no;;
+             gl_cv_func_dup2_works="guessing no" ;;
            cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
-             gl_cv_func_dup2_works=no;;
+             gl_cv_func_dup2_works="guessing no" ;;
            linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
                    # closed fd may yield -EBADF instead of -1 / errno=EBADF.
-             gl_cv_func_dup2_works=no;;
+             gl_cv_func_dup2_works="guessing no" ;;
            freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF.
-             gl_cv_func_dup2_works=no;;
+             gl_cv_func_dup2_works="guessing no" ;;
            haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
-             gl_cv_func_dup2_works=no;;
-           *) gl_cv_func_dup2_works=yes;;
+             gl_cv_func_dup2_works="guessing no" ;;
+           *) gl_cv_func_dup2_works="guessing yes" ;;
          esac])
       ])
-    if test "$gl_cv_func_dup2_works" = no; then
-      gl_REPLACE_DUP2
-    fi
+    case "$gl_cv_func_dup2_works" in
+      *yes) ;;
+      *)
+        REPLACE_DUP2=1
+        ;;
+    esac
   fi
+  dnl Replace dup2() for supporting the gnulib-defined fchdir() function,
+  dnl to keep fchdir's bookkeeping up-to-date.
+  m4_ifdef([gl_FUNC_FCHDIR], [
+    gl_TEST_FCHDIR
+    if test $HAVE_FCHDIR = 0; then
+      if test $HAVE_DUP2 = 1; then
+        REPLACE_DUP2=1
+      fi
+    fi
+  ])
 ])
 
-AC_DEFUN([gl_REPLACE_DUP2],
-[
-  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
-  if test $ac_cv_func_dup2 = yes; then
-    REPLACE_DUP2=1
-  fi
-  AC_LIBOBJ([dup2])
-])
+# Prerequisites of lib/dup2.c.
+AC_DEFUN([gl_PREREQ_DUP2], [])