Imported Upstream version 1.23

[tar] / gnu / fdopendir.c

diff --git a/gnu/fdopendir.c b/gnu/fdopendir.c
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+/* -*- buffer-read-only: t -*- vi: set ro: */
+/* DO NOT EDIT! GENERATED AUTOMATICALLY! */
+/* provide a replacement fdopendir function
+   Copyright (C) 2004-2010 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* written by Jim Meyering */
+
+#include <config.h>
+
+#include <dirent.h>
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#if !HAVE_FDOPENDIR
+
+# include "openat.h"
+# include "openat-priv.h"
+# include "save-cwd.h"
+
+# if GNULIB_DIRENT_SAFER
+#  include "dirent--.h"
+# endif
+
+/* Replacement for Solaris' function by the same name.
+   <http://www.google.com/search?q=fdopendir+site:docs.sun.com>
+   First, try to simulate it via opendir ("/proc/self/fd/FD").  Failing
+   that, simulate it by using fchdir metadata, or by doing
+   save_cwd/fchdir/opendir(".")/restore_cwd.
+   If either the save_cwd or the restore_cwd fails (relatively unlikely),
+   then give a diagnostic and exit nonzero.
+   Otherwise, this function works just like Solaris' fdopendir.
+
+   W A R N I N G:
+   Unlike other fd-related functions, this one effectively consumes
+   its FD parameter.  The caller should not close or otherwise
+   manipulate FD if this function returns successfully.  Also, this
+   implementation does not guarantee that dirfd(fdopendir(n))==n;
+   the open directory stream may use a clone of FD, or have no
+   associated fd at all.  */
+DIR *
+fdopendir (int fd)
+{
+  int saved_errno;
+  DIR *dir;
+
+  char buf[OPENAT_BUFFER_SIZE];
+  char *proc_file = openat_proc_name (buf, fd, ".");
+  if (proc_file)
+    {
+      dir = opendir (proc_file);
+      saved_errno = errno;
+    }
+  else
+    {
+      dir = NULL;
+      saved_errno = EOPNOTSUPP;
+    }
+
+  /* If the syscall fails with an expected errno value, resort to
+     save_cwd/restore_cwd.  */
+  if (! dir && EXPECTED_ERRNO (saved_errno))
+    {
+# if REPLACE_FCHDIR
+      const char *name = _gl_directory_name (fd);
+      if (name)
+        dir = opendir (name);
+      saved_errno = errno;
+# else /* !REPLACE_FCHDIR */
+      struct saved_cwd saved_cwd;
+      if (save_cwd (&saved_cwd) != 0)
+        openat_save_fail (errno);
+
+      if (fchdir (fd) != 0)
+        {
+          dir = NULL;
+          saved_errno = errno;
+        }
+      else
+        {
+          dir = opendir (".");
+          saved_errno = errno;
+
+          if (restore_cwd (&saved_cwd) != 0)
+            openat_restore_fail (errno);
+        }
+
+      free_cwd (&saved_cwd);
+# endif /* !REPLACE_FCHDIR */
+    }
+
+  if (dir)
+    close (fd);
+  if (proc_file != buf)
+    free (proc_file);
+  errno = saved_errno;
+  return dir;
+}
+
+#else /* HAVE_FDOPENDIR */
+
+# include <errno.h>
+# include <sys/stat.h>
+
+# undef fdopendir
+
+/* Like fdopendir, but work around GNU/Hurd bug by validating FD.  */
+
+DIR *
+rpl_fdopendir (int fd)
+{
+  struct stat st;
+  if (fstat (fd, &st))
+    return NULL;
+  if (!S_ISDIR (st.st_mode))
+    {
+      errno = ENOTDIR;
+      return NULL;
+    }
+  return fdopendir (fd);
+}
+
+#endif /* HAVE_FDOPENDIR */