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/* Hurd unionfs
Copyright (C) 2001, 2002 Free Software Foundation, Inc.
Written by Moritz Schulte <moritz@duesseldorf.ccc.de>.
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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA. */
/* `light node' management. See unionfs.h for an explanation of light
nodes. */
#define _GNU_SOURCE
#include <hurd/netfs.h>
#include <error.h>
#include <stdlib.h>
#include <string.h>
#include "lnode.h"
#include "lib.h"
#include "unionfs.h"
/* Create a new light node as an entry with the name NAME and store it
in *NODE. The new node is not locked and contains a single
reference. */
error_t
lnode_create (char *name, lnode_t **node)
{
lnode_t *node_new = malloc (sizeof (lnode_t));
error_t err = 0;
debug_msg ("lnode_create for name: %s", name);
if (! node_new)
err = ENOMEM;
else
{
char *name_cp = NULL;
if (name)
name_cp = strdup (name);
if (name && (! name_cp))
{
err = ENOMEM;
free (node_new);
}
else
{
node_new->name = name_cp;
node_new->name_len = name_cp ? strlen (name_cp) : 0;
node_new->flags = 0;
node_new->node = NULL;
node_new->next = NULL;
node_new->prevp = NULL;
node_new->dir = NULL;
node_new->entries = NULL;
node_new->references = 1;
mutex_init (&node_new->lock);
mutex_lock (&node_new->lock);
*node = node_new;
}
}
return err;
}
/* Destroy a light node. */
void
lnode_destroy (lnode_t *node)
{
debug_msg ("lnode_destroy for name: %s", node->name);
free (node->name);
free (node);
}
/* Install the node in the node tree; add a reference to DIR, which
must be locked. */
void
lnode_install (lnode_t *dir, lnode_t *node)
{
lnode_ref_add (dir);
node->next = dir->entries;
node->prevp = &dir->entries;
if (dir->entries)
dir->entries->prevp = &node->next;
dir->entries = node;
node->dir = dir;
}
/* Uninstall the node from the node tree; remove a reference from the
lnode containing NODE. */
void
lnode_uninstall (lnode_t *node)
{
lnode_ref_remove (node->dir);
*node->prevp = node->next;
if (node->next)
node->next->prevp = &node->next;
}
/* Add a reference to NODE, which must be locked. */
void
lnode_ref_add (lnode_t *node)
{
node->references++;
}
/* Remove a reference to NODE, which must be locked. If that was the
last reference, destroy the node, otherwise simply unlock NODE. */
void
lnode_ref_remove (lnode_t *node)
{
assert (node->references);
if (! --node->references)
{
lnode_uninstall (node);
lnode_destroy (node);
}
else
mutex_unlock (&node->lock);
}
/* Get a light node by it's name. The looked up node is locked and
got one reference added. */
error_t
lnode_get (lnode_t *dir, char *name,
lnode_t **node)
{
error_t err = 0;
lnode_t *n;
for (n = dir->entries; n && strcmp (n->name, name); n = n->next);
if (n)
{
mutex_lock (&n->lock);
lnode_ref_add (n);
*node = n;
}
else
err = ENOENT;
return err;
}
/* Construct the full path for a given light node. */
error_t
lnode_path_construct (lnode_t *node,
char **path)
{
error_t err = 0;
int p_len = 1;
lnode_t *n;
char *p;
for (n = node; n && n->dir; n = n->dir)
p_len += n->name_len + (n->dir->dir ? 1 : 0);
p = malloc (p_len);
if (! p)
err = ENOMEM;
else
{
*(p + --p_len) = 0;
for (n = node; n && n->dir; n = n->dir)
{
p_len -= n->name_len;
strncpy (p + p_len, n->name, n->name_len);
if (n->dir->dir)
*(p + --p_len) = '/';
}
*path = p;
}
return err;
}
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