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/* This is part of um-ViewOS
* The user-mode implementation of OSVIEW -- A Process with a View
*
* umviewos -> fuse gateway
* open file hash table (to rename open deleted files)
*
* Copyright 2009 Renzo Davoli University of Bologna - Italy
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* 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.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <umfuse_node.h>
#define NODE_HASH_SIZE 128
#define NODE_HASH_MASK (NODE_HASH_SIZE-1)
static struct fuse_node *node_head[NODE_HASH_SIZE];
static inline struct fuse_node *node_alloc() {
return (struct fuse_node *)malloc(sizeof (struct fuse_node));
}
static inline void node_free(struct fuse_node *vnode) {
free(vnode);
}
static inline long vnode_hash_sum(void *fuse, char *path) {
long sum = (long) fuse;
while (*path != 0) {
sum ^= ((sum << 5) + (sum >> 2) + *path);
path++;
}
return sum;
}
static inline int vnode_hash_mod(long sum)
{
return sum & NODE_HASH_MASK;
}
static inline struct fuse_node *node_find(void *fuse, char *path,
long hashsum, int hashkey)
{
struct fuse_node *scan=node_head[hashkey];
//printk("node_find %s\n",path);
while (scan != NULL) {
//printk("node_find_scan %s\n",path,scan->path);
if (scan->hashsum == hashsum && scan->fuse == fuse &&
strcmp(scan->path, path) == 0)
return scan;
scan=scan->nexthash;
}
return NULL;
}
struct fuse_node *node_add(void *fuse, char *path)
{
long hashsum = vnode_hash_sum(fuse, path);
int hashkey = vnode_hash_mod(hashsum);
struct fuse_node *new = node_find(fuse, path, hashsum, hashkey);
//printk("+%s %ld %d %p\n",path,hashsum,hashkey,new);
if (new != NULL)
new->open_count++;
else {
new = node_alloc();
if (new != NULL) {
new->fuse=fuse;
new->hashsum=hashsum;
new->open_count=1;
new->path=strdup(path);
if (node_head[hashkey] != NULL)
node_head[hashkey]->pprevhash = &(new->nexthash);
new->nexthash = node_head[hashkey];
new->pprevhash = &(node_head[hashkey]);
node_head[hashkey] = new;
}
}
return new;
}
struct fuse_node *node_search(void *fuse, char *path)
{
long hashsum = vnode_hash_sum(fuse, path);
int hashkey = vnode_hash_mod(hashsum);
struct fuse_node *rv=node_find(fuse, path, hashsum, hashkey);
//printk("%s %ld %d %p\n",path,hashsum,hashkey,rv);
return rv;
}
void node_del(struct fuse_node *old)
{
if (old) {
old->open_count--;
if (old->open_count == 0) {
free(old->path);
*(old->pprevhash)=old->nexthash;
if (old->nexthash)
old->nexthash->pprevhash=old->pprevhash;
}
}
}
void node_newpath(struct fuse_node *node, char *newpath)
{
long hashsum = vnode_hash_sum(node->fuse, newpath);
int hashkey = vnode_hash_mod(hashsum);
/* delete the node from its old position in the hash table */
*(node->pprevhash)=node->nexthash;
if (node->nexthash)
node->nexthash->pprevhash=node->pprevhash;
/* change path and hashsum */
free(node->path);
node->path=strdup(newpath);
node->hashsum=hashsum;
/* add it by its new hashkey */
if (node_head[hashkey] != NULL)
node_head[hashkey]->pprevhash = &(node->nexthash);
node->nexthash = node_head[hashkey];
node->pprevhash = &(node_head[hashkey]);
node_head[hashkey] = node;
}
char *node_hiddenpath(struct fuse_node *node)
{
char *name;
static unsigned long hiddencount;
asprintf(&name,"/.fuse%010u%010lu",(unsigned)node->fuse,hiddencount++);
return name;
}
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