1 files changed, 92 insertions, 0 deletions
diff --git a/lib/dup.c b/lib/dup.c
new file mode 100644
index 0000000..21e9f1f
--- /dev/null
+++ b/lib/dup.c
@@ -0,0 +1,92 @@
+/* Duplicate an open file descriptor.
+
+   Copyright (C) 2011-2023 Free Software Foundation, Inc.
+
+   This file 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 2.1 of the
+   License, or (at your option) any later version.
+
+   This file 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 <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <unistd.h>
+
+#include <errno.h>
+
+#if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+# include "msvc-inval.h"
+#endif
+
+#undef dup
+
+#if defined _WIN32 && !defined __CYGWIN__
+# if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+static int
+dup_nothrow (int fd)
+{
+  int result;
+
+  TRY_MSVC_INVAL
+    {
+      result = _dup (fd);
+    }
+  CATCH_MSVC_INVAL
+    {
+      result = -1;
+      errno = EBADF;
+    }
+  DONE_MSVC_INVAL;
+
+  return result;
+}
+# else
+#  define dup_nothrow _dup
+# endif
+#elif defined __KLIBC__
+# include <fcntl.h>
+# include <sys/stat.h>
+
+# include <InnoTekLIBC/backend.h>
+
+static int
+dup_nothrow (int fd)
+{
+  int dupfd;
+  struct stat sbuf;
+
+  dupfd = dup (fd);
+  if (dupfd == -1 && errno == ENOTSUP \
+      && !fstat (fd, &sbuf) && S_ISDIR (sbuf.st_mode))
+    {
+      char path[_MAX_PATH];
+
+      /* Get a path from fd */
+      if (!__libc_Back_ioFHToPath (fd, path, sizeof (path)))
+        dupfd = open (path, O_RDONLY);
+    }
+
+  return dupfd;
+}
+#else
+# define dup_nothrow dup
+#endif
+
+int
+rpl_dup (int fd)
+{
+  int result = dup_nothrow (fd);
+#if REPLACE_FCHDIR
+  if (result >= 0)
+    result = _gl_register_dup (fd, result);
+#endif
+  return result;
+}