Tolerate declared but missing dup3 syscall.

diff --git a/ChangeLog b/ChangeLog
index 3f8349d429731b66eb9bb1d6704926f5213be955..a24ed561937d36a11f1b19a3f5057215ab38a39a 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2009-08-23  Bruno Haible  <bruno@clisp.org>
+
+       Tolerate declared but missing dup3 syscall.
+       * lib/dup3.c (dup3): Invoke original dup3 function first, if available.
+       * lib/unistd.in.h (dup3): If the function is already present,
+       override it.
+       * m4/dup3.m4 (gl_FUNC_DUP3): Remove AC_LIBOBJ invocation.
+       * modules/dup3 (Makefile.am): Compile dup3.c always.
+       Reported by Paolo Bonzini.
+
 2009-08-23  Bruno Haible  <bruno@clisp.org>
 
        Tolerate declared but missing pipe2 syscall.

diff --git a/lib/dup3.c b/lib/dup3.c
index b9fb341f3b3fe94df45233ef6a0fee21b6a9d8cc..62cdb53d317a73611339ed649d8a3f9fbe4fe3b0 100644 (file)
--- a/lib/dup3.c
+++ b/lib/dup3.c
@@ -48,6 +48,17 @@
 int
 dup3 (int oldfd, int newfd, int flags)
 {
+#if HAVE_DUP3
+# undef dup3
+  /* Try the system call first, if it exists.  (We may be running with a glibc
+     that has the function but with an older kernel that lacks it.)  */
+  {
+    int result = dup3 (oldfd, newfd, flags);
+    if (!(result < 0 && errno == ENOSYS))
+      return result;
+  }
+#endif
+
   if (oldfd < 0 || newfd < 0 || newfd >= getdtablesize ())
     {
       errno = EBADF;

diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index 2f3be174006c3465ac6dc287e768ce90115c8208..e81d35c6755937340e567fc98c7cac1adff226c7 100644 (file)
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -179,7 +179,6 @@ extern int dup2 (int oldfd, int newfd);
 
 
 #if @GNULIB_DUP3@
-# if !@HAVE_DUP3@
 /* Copy the file descriptor OLDFD into file descriptor NEWFD, with the
    specified flags.
    The flags are a bitmask, possibly including O_CLOEXEC (defined in <fcntl.h>)
@@ -188,8 +187,10 @@ extern int dup2 (int oldfd, int newfd);
    Return newfd if successful, otherwise -1 and errno set.
    See the Linux man page at
    <http://www.kernel.org/doc/man-pages/online/pages/man2/dup3.2.html>.  */
-extern int dup3 (int oldfd, int newfd, int flags);
+# if @HAVE_DUP3@
+#  define dup3 rpl_dup3
 # endif
+extern int dup3 (int oldfd, int newfd, int flags);
 #elif defined GNULIB_POSIXCHECK
 # undef dup3
 # define dup3(o,n,f) \

diff --git a/m4/dup3.m4 b/m4/dup3.m4
index e4fe7a6abc8ddc77a9a9ee5bcec139bdff0af281..0640ca934bbee4e280697c20daef609bb50547be 100644 (file)
--- a/m4/dup3.m4
+++ b/m4/dup3.m4
@@ -1,4 +1,4 @@
-# dup3.m4 serial 1
+# dup3.m4 serial 2
 dnl Copyright (C) 2009 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -14,6 +14,5 @@ AC_DEFUN([gl_FUNC_DUP3],
   AC_CHECK_FUNCS_ONCE([dup3])
   if test $ac_cv_func_dup3 != yes; then
     HAVE_DUP3=0
-    AC_LIBOBJ([dup3])
   fi
 ])

diff --git a/modules/dup3 b/modules/dup3
index 38bdcf039c95cefcbf340416217efcea8b51afc6..46650441db51361c8d62a48370f613a9033712f0 100644 (file)
--- a/modules/dup3
+++ b/modules/dup3
@@ -16,6 +16,7 @@ gl_FUNC_DUP3
 gl_UNISTD_MODULE_INDICATOR([dup3])
 
 Makefile.am:
+lib_SOURCES += dup3.c
 
 Include:
 <unistd.h>