1 files changed, 97 insertions, 0 deletions
diff --git a/lib/dup2.c b/lib/dup2.c
new file mode 100644
index 0000000..a7d3cfd
--- /dev/null
+++ b/lib/dup2.c
@@ -0,0 +1,97 @@
+/* Duplicate an open file descriptor to a specified file descriptor.
+
+   Copyright (C) 1999, 2004, 2005, 2006, 2007, 2009 Free Software
+   Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* written by Paul Eggert */
+
+#include <config.h>
+
+/* Specification.  */
+#include <unistd.h>
+
+#include <errno.h>
+#include <fcntl.h>
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+/* Get declarations of the Win32 API functions.  */
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+#endif
+
+#if REPLACE_DUP2
+
+# undef dup2
+
+int
+rpl_dup2 (int fd, int desired_fd)
+{
+  int result;
+# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+  /* If fd is closed, mingw hangs on dup2 (fd, fd).  If fd is open,
+     dup2 (fd, fd) returns 0, but all further attempts to use fd in
+     future dup2 calls will hang.  */
+  if (fd == desired_fd)
+    {
+      if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
+        {
+          errno = EBADF;
+          return -1;
+        }
+      return fd;
+    }
+# endif
+  result = dup2 (fd, desired_fd);
+  if (result == 0)
+    result = desired_fd;
+  return result;
+}
+
+#else /* !REPLACE_DUP2 */
+
+/* On older platforms, dup2 did not exist.  */
+
+# ifndef F_DUPFD
+static int
+dupfd (int fd, int desired_fd)
+{
+  int duplicated_fd = dup (fd);
+  if (duplicated_fd < 0 || duplicated_fd == desired_fd)
+    return duplicated_fd;
+  else
+    {
+      int r = dupfd (fd, desired_fd);
+      int e = errno;
+      close (duplicated_fd);
+      errno = e;
+      return r;
+    }
+}
+# endif
+
+int
+dup2 (int fd, int desired_fd)
+{
+  if (fd == desired_fd)
+    return fd;
+  close (desired_fd);
+# ifdef F_DUPFD
+  return fcntl (fd, F_DUPFD, desired_fd);
+# else
+  return dupfd (fd, desired_fd);
+# endif
+}
+#endif /* !REPLACE_DUP2 */