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/* Default hooks for directory nodes
Copyright (C) 1995 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <sys/fcntl.h>
#include "treefs.h"
/* ---------------------------------------------------------------- */
/* Return in CHILD a new node with one reference, presumably a possible child
of DIR, with a mode MODE. All attempts to create a new node go through
this hook, so it may be overridden to easily control creation (e.g.,
replacing it with a hook that always returns EPERM). Note that this
routine doesn't actually enter the child into the directory, or give the
node a non-zero link count, that should be done by the caller. */
error_t
_treefs_dir_create_child (struct treefs_node *dir,
mode_t mode, struct treefs_auth *auth,
struct treefs_node **child)
{
error_t err;
if (!treefs_node_isdir (dir))
return ENOTDIR;
err = treefs_fsys_create_node (dir->fsys, dir, mode, auth, child);
if (err)
return err;
return 0;
}
/* ---------------------------------------------------------------- */
/* Lookup NAME in DIR, returning the result in CHILD; AUTH should be used to
do authentication. FLAGS is the open flags; if FLAGS contains O_CREAT,
and NAME is not found, then an entry should be created with a mode of
CREATE_MODE (which includes the S_IFMT bits, e.g., S_IFREG means a normal
file), unless O_EXCL is also set, in which case EEXIST should be returned.
Possible special errors returned include: EAGAIN -- result would be the
parent of our filesystem root. */
error_t
_treefs_dir_lookup (struct treefs_node *dir, char *name,
struct treefs_auth *auth,
int flags, int create_mode,
struct treefs_node **child)
{
error_t err;
if (strcmp (name, "..") == 0 && dir == dir->fsys->root)
/* Whoops, the result is above our heads. */
err = EAGAIN;
else
/* See if we've got an in-core entry for this file. */
err = treefs_mdir_get (dir, name, child);
if (err == 0 && (flags & O_EXCL))
return EEXIST;
if (err == ENOENT)
/* See if there's some other way of getting this file. */
err = treefs_dir_noent (dir, name, auth, flags, create_mode, child);
if (err == ENOENT && (flags & O_CREAT))
/* No such file, but the user wants to create it. */
{
err = treefs_dir_create_child (dir, create_mode, auth, child);
if (!err)
{
err = treefs_dir_link (dir, name, *child, auth);
if (err)
treefs_node_unref (*child);
}
}
return err;
}
/* ---------------------------------------------------------------- */
/* Link the node CHILD into DIR as NAME, using AUTH to check authentication.
DIR should be locked and CHILD shouldn't be. The default hook puts it
into DIR's in-core directory, and uses a reference to CHILD. */
error_t
_treefs_dir_link (struct treefs_node *dir, char *name,
struct treefs_node *child, struct treefs_auth *auth)
{
struct treefs_node *old_child;
error_t err = treefs_node_mod_link_count (child, 1);
if (!err)
{
err = treefs_mdir_add (dir, name, child, &old_child);
if (err)
/* back out */
treefs_node_mod_link_count (child, -1);
else if (old_child)
treefs_node_mod_link_count (old_child, -1);
}
return err;
}
/* Remove the entry NAME from DIR, using AUTH to check authentication. DIR
should be locked. The default hook removes NAME from DIR's in-core
directory. */
error_t
_treefs_dir_unlink (struct treefs_node *dir, char *name,
struct treefs_auth *auth)
{
struct treefs_node *old_child;
error_t err = treefs_mdir_remove (dir, name, &old_child);
if (!err && old_child)
{
treefs_node_mod_link_count (old_child, -1);
treefs_node_unref (old_child);
}
return err;
}
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