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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 */
/*
* A general filesystem backend.
*/
#ifndef __FS_BACKEND__
#define __FS_BACKEND__
#include <hurd/netfs.h>
#include <dirent.h>
#include <argp.h>
#include <assert.h>
/* Generic (fs independent) netnode structure. */
struct netnode
{
char *name; /* node name */
char *symlink; /* link's target path (in the case of a symlink) */
struct node *hardlink;/* hard link's target or zero */
struct node *entries; /* directory entries (when applies) */
struct node *dir; /* parent directory */
void *info; /* fs defined data (node related info) */
};
/* Substitute for '/' and chars lower than 32 in node names.
If SUBST_LOWER isn't defined, then lower chars won't be filtered. */
#define SUBST_SLASH '|'
//#define SUBST_LOWER '.'
/* Each filesystem backend should define a struct fs_backend variable with
the appropriate functions. */
struct fs_backend
{
/* Initialize filesystem (create root node *N, etc.) */
error_t (* init)(struct node **n, struct iouser *user);
/* Get filesystem's struct argp. */
void (* get_argp)(struct argp *s);
/* Get arguments (see netfs_append_args()). */
error_t (*get_args)(char **argz, unsigned *argz_len);
/* Set options (see netfs_set_options()). */
error_t (*set_options)(char *argz, size_t argz_len);
/*
* Directory scan functions (used in netfs_get_dirents ()).
*/
/* Set current directory. */
int (* set_curr_dir)(struct node *dir);
/* Skip N entries in current directory, returns non-zero if
no more entries are available. */
int (* skip_entries)(int n);
/* Returns a newly-allocated entry in ENTRY. Returns non-zero when
no more entries are available. */
int (* get_next_entry)(struct dirent **entry);
/* Reading a node */
error_t (* lookup_node)(struct node **np, struct node* dir, const char* name);
error_t (* read_node) (struct node *np, off_t offset,
size_t *len, void* data);
/* Changing a node */
error_t (* write_node) (struct node *np, off_t offset,
size_t *len, void* data);
/* Change NP's stats. */
error_t (* change_stat)(struct node *np, const io_statbuf_t *new_stat);
/* Creates a node named NAME in DIR which is locked. */
error_t (* create_node) (struct node **new, struct node *dir,
char *name, mode_t m);
/* Unlinks NODE. NODE can be a directory in which case it is empty. */
error_t (* unlink_node) (struct node *node);
/* Tries to create a hard link named NAME in DIR to file NODE. */
error_t (* link_node) (struct node *dir, struct node *target,
char *name, int excl); /* Same as netfs semantics */
/* Makes NODE a symlink to TARGET. */
error_t (* symlink_node) (struct node *node, const char *target);
/* Tries to turn NODE into a device of type TYPE (either S_IFBLK
or S_IFCHR). */
error_t (* mkdev_node) (struct node *node, mode_t type, dev_t indexes);
/* Free all resources associated to NODE. */
void (* free_node) (struct node *node);
/* Synchronize filesystem. */
error_t (* sync_fs) (int wait);
/* Filesystem destructor */
error_t (* go_away) ();
};
#endif
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