linux: Move posix dir implementations to Linux

This generic implementation already expects a getdents API which
is Linux specific.  It also allows simplify it by assuming
_DIRENT_HAVE_D_RECLEN and _DIRENT_HAVE_D_OFF support.

The readdir are also expanded on each required implementation,
futher fixes and improvements will make parametrize the
implementation more complex.

Checked on x86_64-linux-gnu, i686-linux-gnu, and with a build
for all affected ABIs.

1 files changed, 31 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/dirfd.c b/sysdeps/unix/sysv/linux/dirfd.c
new file mode 100644
index 0000000000..5d0928dca4
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/dirfd.c
@@ -0,0 +1,31 @@
+/* Return the file descriptor used by a DIR stream.  Unix version.
+   Copyright (C) 1995-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library 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.
+
+   The GNU C Library 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 the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dirent.h>
+#include <dirstream.h>
+
+#undef dirfd
+
+int
+__dirfd (DIR *dirp)
+{
+  return dirp->fd;
+}
+
+weak_alias (__dirfd, dirfd)
+libc_hidden_def (dirfd)