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/* tarfs - A GNU tar filesystem for the Hurd.
Copyright (C) 2002, Ludovic Courtès <ludo@chbouib.org>
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 */
/* Tar list management functions. This is used as a model representing
the contents of a tar file, i.e. the items in the order in which they
appear (or should appear) in the tar file. */
#include <hurd/netfs.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <error.h>
#include "tarfs.h"
#include "fs.h"
#include "debug.h"
/* Initialize LIST. */
void
tar_list_init (struct tar_list *list)
{
list->head = NULL;
mutex_init (&list->lock);
}
/* Make a tar item containing the given information. NEW points to the
newly created item. */
error_t
tar_make_item (struct tar_item **new_item,
struct node *node, size_t orig_size, off_t offset)
{
struct tar_item *new;
new = calloc (1, sizeof (struct tar_item));
if (! new)
return ENOMEM;
assert (node != NULL);
new->orig_size = orig_size;
new->offset = offset;
new->node = node;
NODE_INFO(node)->tar = new;
*new_item = new;
return 0;
}
/* Insert tar item NEW right after PREV in LIST. */
error_t
tar_insert_item (struct tar_list *list,
struct tar_item *prev, struct tar_item *new)
{
struct tar_item **head, *next;
assert (prev != new);
mutex_lock (&list->lock);
head = &list->head;
if (! prev)
if (! *head)
{
*head = new;
next = NULL;
}
else
{
prev = *head;
next = (*head)->next;
(*head)->next = new;
}
else
{
next = prev->next;
prev->next = new;
}
new->prev = prev;
new->next = next;
if (next)
next->prev = new;
mutex_unlock (&list->lock);
return 0;
}
/* Remove ITEM from LIST. */
void
tar_unlink_item_safe (struct tar_list *list, struct tar_item *item)
{
struct tar_item **head;
/* The corresponding node should have been destroyed first. */
assert (item->node == NULL);
head = &list->head;
/* Make sure LIST is not already empty */
assert (*head != NULL);
if (! item->prev)
{
*head = item->next;
if (*head)
(*head)->prev = NULL;
}
else
{
item->prev->next = item->next;
if (item->next)
item->next->prev = item->prev;
}
/* Free ITEM. */
free (item);
}
void
tar_unlink_item (struct tar_list *list, struct tar_item *tar)
{
mutex_lock (&list->lock);
tar_unlink_item_safe (list, tar);
mutex_unlock (&list->lock);
}
/* Attempt to find a place for TAR, an new yet unlinked tar item, into the
tar list in an optimal way. Returns in PREV_ITEM the item after which
TAR should be inserted but don't actually insert it. */
void
tar_put_item (struct tar_item **prev_tar, struct tar_item *tar)
{
struct node *node = tar->node;
struct node *dir, *last_entry;
/* TAR has to be linked to the filesystem. */
assert (tar->node);
dir = node->nn->dir;
/* Try to insert the node inside the tar list in such a way that it
appears:
- after its parent directory;
- after all the entries of its parent dir;
- after the last entry of its parent dir's last entry.
The 1st thing is needed to have a consistent tar archive, and the two
latter requirements are needed for better performance at sync time
(it avoids having to sync everything before NEWNODE).
So that we have, for instance:
0: file
1: dir/
2: dir/file1
3: dir/file2
4: NEWNODE. */
last_entry = dir->nn->entries;
if (last_entry)
{
/* Get a reference to DIR's last entry. */
struct node *next;
for ( ;
(next = last_entry->next) != NULL;
last_entry = next)
{
if (next == node)
{
/* If LAST_ENTRY is TAR's node... */
if (node->next)
/* ... skip it */
next = node->next;
else
/* ... or keep the next-to-last entry */
break;
}
}
if (last_entry == node)
last_entry = NULL;
/* Jump to the last node of LAST_ENTRY's deepest subdir */
while (last_entry)
{
/* If it's a directory, get its last entry. */
if ( (S_ISDIR (last_entry->nn_stat.st_mode))
&& (last_entry->nn->entries) )
{
for (last_entry = last_entry->nn->entries;
last_entry->next;
last_entry = last_entry->next);
}
else
break;
}
}
if ((last_entry) && (last_entry != node))
{
assert (NODE_INFO(last_entry)->tar);
*prev_tar = NODE_INFO(last_entry)->tar;
}
else
{
if (dir == netfs_root_node)
*prev_tar = NULL;
else
*prev_tar = NODE_INFO(dir)->tar;
}
return;
}
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