libdiskfs: add fsys_get_source

Add a user overridable function diskfs_get_source with a default
implementation returning EOPNOTSUPP. Add a server function for
fsys-get-source.

* libdiskfs/Makefile: Add fsys-get-source.c and get-source.c
* libdiskfs/diskfs.h: Add diskfs_get_source.
* libdiskfs/fsys-get-source.c: New file.
* libdiskfs/get-source.c: Likewise.

4 files changed, 71 insertions, 3 deletions

diff --git a/libdiskfs/Makefile b/libdiskfs/Makefile
index 1a0edd00..03c2e2b3 100644
--- a/libdiskfs/Makefile
+++ b/libdiskfs/Makefile
@@ -35,7 +35,7 @@ IOSRCS= io-async-icky.c io-async.c io-duplicate.c io-get-conch.c io-revoke.c \
 	io-select.c io-stat.c io-stubs.c io-write.c io-version.c io-sigio.c
 FSYSSRCS=fsys-getroot.c fsys-goaway.c fsys-startup.c fsys-getfile.c \
 	fsys-options.c fsys-syncfs.c fsys-forward.c \
-	fsys-get-children.c
+	fsys-get-children.c fsys-get-source.c
 IFSOCKSRCS=ifsock.c
 OTHERSRCS = conch-fetch.c conch-set.c dir-clear.c dir-init.c dir-renamed.c \
 	extern-inline.c \
@@ -52,7 +52,7 @@ OTHERSRCS = conch-fetch.c conch-set.c dir-clear.c dir-init.c dir-renamed.c \
 	remount.c console.c disk-pager.c \
 	name-cache.c direnter.c dirrewrite.c dirremove.c lookup.c dead-name.c \
 	validate-mode.c validate-group.c validate-author.c validate-flags.c \
-	validate-rdev.c validate-owner.c extra-version.c
+	validate-rdev.c validate-owner.c extra-version.c get-source.c
 SRCS = $(OTHERSRCS) $(FSSRCS) $(IOSRCS) $(FSYSSRCS) $(IFSOCKSRCS)
 installhdrs = diskfs.h diskfs-pager.h
 
diff --git a/libdiskfs/diskfs.h b/libdiskfs/diskfs.h
index 24895172..22262aa8 100644
--- a/libdiskfs/diskfs.h
+++ b/libdiskfs/diskfs.h
@@ -1,7 +1,7 @@
 /* Definitions for fileserver helper functions
 
    Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002, 2007, 2008,
-   2009 Free Software Foundation, Inc.
+   2009, 2013 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
@@ -567,6 +567,12 @@ error_t (*diskfs_create_symlink_hook)(struct node *np, const char *target);
    isn't set, then the normal method (reading from the file data) is
    used.  If it returns any other error, it is returned to the user. */
 error_t (*diskfs_read_symlink_hook)(struct node *np, char *target);
+
+/* The user may define this function.  The function must set source to
+   the source device of the filesystem. The function may return an
+   EOPNOTSUPP to indicate that the concept of a source device is not
+   applicable. The default function always returns EOPNOTSUPP. */
+error_t diskfs_get_source (char *source);
 
 /* The library exports the following functions for general use */
 
diff --git a/libdiskfs/fsys-get-source.c b/libdiskfs/fsys-get-source.c
new file mode 100644
index 00000000..08f227c9
--- /dev/null
+++ b/libdiskfs/fsys-get-source.c
@@ -0,0 +1,34 @@
+/* fsys_get_source
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+
+   Written by Justus Winter <4winter@informatik.uni-hamburg.de>
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd 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 2, or (at your option)
+   any later version.
+
+   The GNU Hurd 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 the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "priv.h"
+#include "fsys_S.h"
+
+/* Return information about the source of the receiving
+   filesystem.	*/
+error_t
+diskfs_S_fsys_get_source (fsys_t server,
+			  mach_port_t reply,
+			  mach_msg_type_name_t replyPoly,
+			  char *source)
+{
+  return diskfs_get_source (source);
+}
diff --git a/libdiskfs/get-source.c b/libdiskfs/get-source.c
new file mode 100644
index 00000000..d0c143be
--- /dev/null
+++ b/libdiskfs/get-source.c
@@ -0,0 +1,28 @@
+/* Default version of diskfs_get_source
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+
+   Written by Justus Winter <4winter@informatik.uni-hamburg.de>
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd 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 2, or (at
+   your option) any later version.
+
+   The GNU Hurd 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 the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "priv.h"
+
+error_t
+diskfs_get_source (char *source)
+{
+  return EOPNOTSUPP;
+}