mc/vfs/vfs.c

/* Virtual File System switch code
   Copyright (C) 1995 The Free Software Foundation
   
   Written by: 1995 Miguel de Icaza
               1995 Jakub Jelinek
	       1998 Pavel Machek
   
   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library 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 Library General Public License for more details.

   You should have received a copy of the GNU Library 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.  */

/* Warning: funtions like extfs_lstat() have right to destroy any
 * strings you pass to them. This is acutally ok as you g_strdup what
 * you are passing to them, anyway; still, beware.  */

/* Namespace: exports *many* functions with vfs_ prefix; exports
   parse_ls_lga and friends which do not have that prefix. */

#include <config.h>

#ifndef NO_SYSLOG_H
#  include <syslog.h>
#endif

#include <stdio.h>
#include <stdlib.h>	/* For atol() */
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <signal.h>
#include <ctype.h>	/* is_digit() */

#include "utilvfs.h"

#include "../src/panel.h"	/* get_current_panel() */
#include "../src/layout.h"	/* get_current_type() */
#include "../src/wtools.h"	/* input_dialog() */

#include "vfs.h"
#ifdef USE_NETCODE
#   include "tcputil.h"
#endif

int vfs_timeout = 60; /* VFS timeout in seconds */

/* They keep track of the current directory */
static struct vfs_class *current_vfs;
static char *current_dir;

struct vfs_openfile {
    int handle;
    struct vfs_class *vclass;
    void *fsinfo;
};

static GSList *vfs_openfiles;
#define VFS_FIRST_HANDLE 100

static struct vfs_class *localfs_class;

/* Create new VFS handle and put it to the list */
static int
vfs_new_handle (struct vfs_class *vclass, void *fsinfo)
{
    static int vfs_handle_counter = VFS_FIRST_HANDLE;
    struct vfs_openfile *h;

    h = g_new (struct vfs_openfile, 1);
    h->handle = vfs_handle_counter++;
    h->fsinfo = fsinfo;
    h->vclass = vclass;
    vfs_openfiles = g_slist_prepend (vfs_openfiles, h);
    return h->handle;
}

/* Function to match handle, passed to g_slist_find_custom() */
static gint
vfs_cmp_handle (gconstpointer a, gconstpointer b)
{
    if (!a)
	return 1;
    return ((struct vfs_openfile *) a)->handle != (int) b;
}

/* Find VFS class by file handle */
static inline struct vfs_class *
vfs_op (int handle)
{
    GSList *l;
    struct vfs_openfile *h;

    l = g_slist_find_custom (vfs_openfiles, (gconstpointer) handle,
			     vfs_cmp_handle);
    if (!l)
	return NULL;
    h = (struct vfs_openfile *) l->data;
    if (!h)
	return NULL;
    return h->vclass;
}

/* Find private file data by file handle */
static inline void *
vfs_info (int handle)
{
    GSList *l;
    struct vfs_openfile *h;

    l = g_slist_find_custom (vfs_openfiles, (gconstpointer) handle,
			     vfs_cmp_handle);
    if (!l)
	return NULL;
    h = (struct vfs_openfile *) l->data;
    if (!h)
	return NULL;
    return h->fsinfo;
}

/* Free open file data for given file handle */
static inline void
vfs_free_handle (int handle)
{
    GSList *l;

    l = g_slist_find_custom (vfs_openfiles, (gconstpointer) handle,
			     vfs_cmp_handle);
    vfs_openfiles = g_slist_delete_link (vfs_openfiles, l);
}

static struct vfs_class *vfs_list;

int
vfs_register_class (struct vfs_class *vfs)
{
    if (vfs->init)		/* vfs has own initialization function */
	if (!(*vfs->init)(vfs))	/* but it failed */
	    return 0;

    vfs->next = vfs_list;
    vfs_list = vfs;

    return 1;
}

/* Return VFS class for the given prefix */
static struct vfs_class *
vfs_prefix_to_class (char *prefix)
{
    struct vfs_class *vfs;

    for (vfs = vfs_list; vfs; vfs = vfs->next) {
	if (vfs->which) {
	    if ((*vfs->which) (vfs, prefix) == -1)
		continue;
	    return vfs;
	}
	if (vfs->prefix
	    && !strncmp (prefix, vfs->prefix, strlen (vfs->prefix)))
	    return vfs;
    }
    return NULL;
}

/* Strip known vfs suffixes from a filename (possible improvement: strip
   suffix from last path component). 
   Returns a malloced string which has to be freed. */
char *
vfs_strip_suffix_from_filename (const char *filename)
{
    struct vfs_class *vfs;
    char *semi;
    char *p;

    if (!filename)
	vfs_die ("vfs_strip_suffix_from_path got NULL: impossible");

    p = g_strdup (filename);
    if (!(semi = strrchr (p, '#')))
	return p;

    /* Avoid last class (localfs) that would accept any prefix */
    for (vfs = vfs_list; vfs->next; vfs = vfs->next) {
	if (vfs->which) {
	    if ((*vfs->which) (vfs, semi + 1) == -1)
		continue;
	    *semi = '\0';	/* Found valid suffix */
	    return p;
	}
	if (vfs->prefix
	    && !strncmp (semi + 1, vfs->prefix, strlen (vfs->prefix))) {
	    *semi = '\0';	/* Found valid suffix */
	    return p;
	}
    }
    return p;
}

static int
path_magic (const char *path)
{
    struct stat buf;

    if (!stat(path, &buf))
        return 0;

    return 1;
}

/*
 * Splits path '/p1#op/inpath' into inpath,op; returns which vfs it is.
 * What is left in path is p1. You still want to g_free(path), you DON'T
 * want to free neither *inpath nor *op
 */
struct vfs_class *
vfs_split (const char *path, char **inpath, char **op)
{
    char *semi;
    char *slash;
    struct vfs_class *ret;

    if (!path)
	vfs_die("Cannot split NULL");
    
    semi = strrchr (path, '#');
    if (!semi || !path_magic(path))
	return NULL;

    slash = strchr (semi, PATH_SEP);
    *semi = 0;

    if (op)
	*op = NULL;

    if (inpath)
	*inpath = NULL;

    if (slash)
	*slash = 0;

    if ((ret = vfs_prefix_to_class (semi+1))){
	if (op) 
	    *op = semi + 1;
	if (inpath)
	    *inpath = slash ? slash + 1 : NULL;
	return ret;
    }


    if (slash)
	*slash = PATH_SEP;
    ret = vfs_split (path, inpath, op);
    *semi = '#';
    return ret;
}

static struct vfs_class *
_vfs_get_class (const char *path)
{
    char *semi;
    char *slash;
    struct vfs_class *ret;

    g_return_val_if_fail(path, NULL);

    semi = strrchr (path, '#');
    if (!semi || !path_magic (path))
	return NULL;
    
    slash = strchr (semi, PATH_SEP);
    *semi = 0;
    if (slash)
	*slash = 0;
    
    ret = vfs_prefix_to_class (semi+1);

    if (slash)
	*slash = PATH_SEP;
    if (!ret)
	ret = _vfs_get_class (path);

    *semi = '#';
    return ret;
}

struct vfs_class *
vfs_get_class (const char *path)
{
    struct vfs_class *vfs;

    vfs = _vfs_get_class(path);

    if (!vfs)
	vfs = localfs_class;

    return vfs;
}

static struct vfs_stamping *stamps;

/*
 * Returns the number of seconds remaining to the vfs timeout
 *
 * FIXME: currently this is set to 10 seconds.  We should compute this.
 */
int
vfs_timeouts ()
{
    return stamps ? 10 : 0;
}

static void
vfs_addstamp (struct vfs_class *v, vfsid id, struct vfs_stamping *parent)
{
    if (!(v->flags & VFSF_LOCAL) && id != (vfsid)-1){
        struct vfs_stamping *stamp;
	struct vfs_stamping *last_stamp = NULL;
        
        for (stamp = stamps; stamp != NULL; stamp = stamp->next) {
            if (stamp->v == v && stamp->id == id){
		gettimeofday(&(stamp->time), NULL);
                return;
	    }
	    last_stamp = stamp;
	}
        stamp = g_new (struct vfs_stamping, 1);
        stamp->v = v;
        stamp->id = id;
	if (parent){
	    struct vfs_stamping *st = stamp;
	    while (parent){
		st->parent = g_new (struct vfs_stamping, 1);
		*st->parent = *parent;
		parent = parent->parent;
		st = st->parent;
	    }
	    st->parent = 0;
	}
	else
    	    stamp->parent = 0;
	
        gettimeofday (&(stamp->time), NULL);
        stamp->next = 0;

	if (stamps) {
	    /* Add to the end */
	    last_stamp->next = stamp;
	} else {
	    /* Add first element */
    	    stamps = stamp;
	}
    }
}

void
vfs_stamp (struct vfs_class *v, vfsid id)
{
    struct vfs_stamping *stamp;

    for (stamp = stamps; stamp != NULL; stamp = stamp->next)
        if (stamp->v == v && stamp->id == id){

            gettimeofday (&(stamp->time), NULL);
            if (stamp->parent != NULL)
                vfs_stamp (stamp->parent->v, stamp->parent->id);

            return;
        }
}

static void
vfs_rm_parents (struct vfs_stamping *stamp)
{
    struct vfs_stamping *parent;

    while (stamp) {
	parent = stamp->parent;
	g_free (stamp);
	stamp = parent;
    }
}

void
vfs_rmstamp (struct vfs_class *v, vfsid id, int removeparents)
{
    struct vfs_stamping *stamp, *st1;

    for (stamp = stamps, st1 = NULL; stamp != NULL;
	 st1 = stamp, stamp = stamp->next)
	if (stamp->v == v && stamp->id == id) {
	    if (stamp->parent != NULL) {
		if (removeparents)
		    vfs_rmstamp (stamp->parent->v, stamp->parent->id, 1);
		vfs_rm_parents (stamp->parent);
		stamp->parent = NULL;
		continue;	/* rescan the tree */
	    }
	    if (st1 == NULL) {
		stamps = stamp->next;
	    } else {
		st1->next = stamp->next;
	    }
	    g_free (stamp);

	    return;
	}
}

static int
ferrno (struct vfs_class *vfs)
{
    return vfs->ferrno ? (*vfs->ferrno)(vfs) : E_UNKNOWN; 
    /* Hope that error message is obscure enough ;-) */
}

int
mc_open (const char *filename, int flags, ...)
{
    int  mode;
    void *info;
    va_list ap;

    char *file = vfs_canon (filename);
    struct vfs_class *vfs = vfs_get_class (file);

    /* Get the mode flag */	/* FIXME: should look if O_CREAT is present */
    va_start (ap, flags);
    mode = va_arg (ap, int);
    va_end (ap);
    
    if (!vfs->open) {
	g_free (file);
	errno = -EOPNOTSUPP;
	return -1;
    }

    info = (*vfs->open) (vfs, file, flags, mode);	/* open must be supported */
    g_free (file);
    if (!info){
	errno = ferrno (vfs);
	return -1;
    }

    return vfs_new_handle (vfs, info);
}

#define MC_OP(name, inarg, callarg, pre, post) \
        int mc_##name inarg \
	{ \
	struct vfs_class *vfs; \
	int result; \
	\
	pre \
	result = vfs->name ? (*vfs->name)callarg : -1; \
        post \
	if (result == -1) \
	    errno = vfs->name ? ferrno (vfs) : E_NOTSUPP; \
	return result; \
	}

#define MC_NAMEOP(name, inarg, callarg) \
  MC_OP (name, inarg, callarg, path = vfs_canon (path); vfs = vfs_get_class (path);, g_free (path); )
#define MC_HANDLEOP(name, inarg, callarg) \
  MC_OP (name, inarg, callarg, if (handle == -1) return -1; vfs = vfs_op (handle);, ;)

MC_HANDLEOP(read, (int handle, char *buffer, int count), (vfs_info (handle), buffer, count) )

int
mc_ctl (int handle, int ctlop, void *arg)
{
    struct vfs_class *vfs = vfs_op (handle);

    return vfs->ctl ? (*vfs->ctl)(vfs_info (handle), ctlop, arg) : 0;
}

int
mc_setctl (char *path, int ctlop, void *arg)
{
    struct vfs_class *vfs;
    int result;

    if (!path)
	vfs_die("You don't want to pass NULL to mc_setctl.");
    
    path = vfs_canon (path);
    vfs = vfs_get_class (path);    
    result = vfs->setctl ? (*vfs->setctl)(vfs, path, ctlop, arg) : 0;
    g_free (path);
    return result;
}

int
mc_close (int handle)
{
    struct vfs_class *vfs;
    int result;

    if (handle == -1 || !vfs_info (handle))
	return -1;
    
    vfs = vfs_op (handle);
    if (handle < 3)
	return close (handle);

    if (!vfs->close)
        vfs_die ("VFS must support close.\n");
    result = (*vfs->close)(vfs_info (handle));
    vfs_free_handle (handle);
    if (result == -1)
	errno = ferrno (vfs);
    
    return result;
}

DIR *
mc_opendir (char *dirname)
{
    int  handle, *handlep;
    void *info;
    struct vfs_class *vfs;

    dirname = vfs_canon (dirname);
    vfs = vfs_get_class (dirname);

    info = vfs->opendir ? (*vfs->opendir)(vfs, dirname) : NULL;
    g_free (dirname);
    if (!info){
        errno = vfs->opendir ? ferrno (vfs) : E_NOTSUPP;
	return NULL;
    }
    handle = vfs_new_handle (vfs, info);

    handlep = g_new (int, 1);
    *handlep = handle;
    return (DIR *) handlep;
}

struct dirent *
mc_readdir (DIR *dirp)
{
    int handle;
    struct vfs_class *vfs;
    struct dirent *result = NULL;

    if (!dirp) {
	errno = EFAULT;
	return NULL;
    }
    handle = *(int *) dirp;
    vfs = vfs_op (handle);
    if (vfs->readdir)
	result = (*vfs->readdir) (vfs_info (handle));
    if (!result)
	errno = vfs->readdir ? ferrno (vfs) : E_NOTSUPP;
    return result;
}

int
mc_closedir (DIR *dirp)
{
    int handle = *(int *) dirp;
    struct vfs_class *vfs = vfs_op (handle);
    int result;

    result = vfs->closedir ? (*vfs->closedir)(vfs_info (handle)) : -1;
    vfs_free_handle (handle);
    g_free (dirp);
    return result; 
}

int mc_stat (const char *filename, struct stat *buf) {
    struct vfs_class *vfs;
    int result;
    char *path;
    path = vfs_canon (filename); vfs = vfs_get_class (path);
    result = vfs->stat ? (*vfs->stat) (vfs, path, buf) : -1;
    g_free (path);
    if (result == -1)
	errno = vfs->name ? ferrno (vfs) : E_NOTSUPP;
    return result;
}

int mc_lstat (const char *filename, struct stat *buf) {
    struct vfs_class *vfs;
    int result;
    char *path;
    path = vfs_canon (filename); vfs = vfs_get_class (path);
    result = vfs->lstat ? (*vfs->lstat) (vfs, path, buf) : -1;
    g_free (path);
    if (result == -1)
	errno = vfs->name ? ferrno (vfs) : E_NOTSUPP;
    return result;
}

int mc_fstat (int handle, struct stat *buf) {
    struct vfs_class *vfs;
    int result;

    if (handle == -1)
	return -1;
    vfs = vfs_op (handle);
    result = vfs->fstat ? (*vfs->fstat) (vfs_info (handle), buf) : -1;
    if (result == -1)
	errno = vfs->name ? ferrno (vfs) : E_NOTSUPP;
    return result;
}

/*
 * Return current directory.  If it's local, reread the current directory
 * from the OS.  You must g_strdup whatever this function returns.
 */
static const char *
_vfs_get_cwd (void)
{
    char *p;
    struct stat my_stat, my_stat2;

    if (!_vfs_get_class (current_dir)) {
	p = g_get_current_dir ();
	if (!p)			/* One of the directories in the path is not readable */
	    return current_dir;

	/* Otherwise check if it is O.K. to use the current_dir */
	if (!cd_symlinks || mc_stat (p, &my_stat)
	    || mc_stat (current_dir, &my_stat2)
	    || my_stat.st_ino != my_stat2.st_ino
	    || my_stat.st_dev != my_stat2.st_dev) {
	    g_free (current_dir);
	    current_dir = p;
	    return p;
	}			/* Otherwise we return current_dir below */
	g_free (p);
    }
    return current_dir;
}

static void
vfs_setup_wd (void)
{
    current_dir = g_strdup (PATH_SEP_STR);
    _vfs_get_cwd ();

    if (strlen (current_dir) > MC_MAXPATHLEN - 2)
	vfs_die ("Current dir too long.\n");

    current_vfs = vfs_get_class (current_dir);
}

/*
 * Return current directory.  If it's local, reread the current directory
 * from the OS.  Put directory to the provided buffer.
 */
char *
mc_get_current_wd (char *buffer, int size)
{
    const char *cwd = _vfs_get_cwd ();

    g_strlcpy (buffer, cwd, size - 1);
    buffer[size - 1] = 0;
    return buffer;
}

/*
 * Return current directory without any OS calls.
 */
char *
vfs_get_current_dir (void)
{
    return current_dir;
}

MC_NAMEOP (chmod, (char *path, int mode), (vfs, path, mode))
MC_NAMEOP (chown, (char *path, int owner, int group), (vfs, path, owner, group))
MC_NAMEOP (utime, (char *path, struct utimbuf *times), (vfs, path, times))
MC_NAMEOP (readlink, (char *path, char *buf, int bufsiz), (vfs, path, buf, bufsiz))
MC_NAMEOP (unlink, (char *path), (vfs, path))
MC_NAMEOP (symlink, (char *name1, char *path), (vfs, name1, path))

#define MC_RENAMEOP(name) \
int mc_##name (const char *fname1, const char *fname2) \
{ \
    struct vfs_class *vfs; \
    int result; \
\
    char *name2, *name1 = vfs_canon (fname1); \
    vfs = vfs_get_class (name1); \
    name2 = vfs_canon (fname2); \
    if (vfs != vfs_get_class (name2)){ \
    	errno = EXDEV; \
    	g_free (name1); \
    	g_free (name2); \
	return -1; \
    } \
\
    result = vfs->name ? (*vfs->name)(vfs, name1, name2) : -1; \
    g_free (name1); \
    g_free (name2); \
    if (result == -1) \
        errno = vfs->name ? ferrno (vfs) : E_NOTSUPP; \
    return result; \
}

MC_RENAMEOP (link)
MC_RENAMEOP (rename)

MC_HANDLEOP (write, (int handle, char *buf, int nbyte), (vfs_info (handle), buf, nbyte))

off_t mc_lseek (int fd, off_t offset, int whence)
{
    struct vfs_class *vfs;
    int result;

    if (fd == -1)
	return -1;

    vfs = vfs_op (fd);
    result = vfs->lseek ? (*vfs->lseek)(vfs_info (fd), offset, whence) : -1;
    if (result == -1)
        errno = vfs->lseek ? ferrno (vfs) : E_NOTSUPP;
    return result;
}

/*
 * remove //, /./ and /../, local should point to big enough buffer
 */

#define ISSLASH(a) (!a || (a == '/'))

char *
vfs_canon (const char *path)
{
    if (!path)
	vfs_die("Cannot canonicalize NULL");

    /* Relative to current directory */
    if (*path != PATH_SEP){ 
    	char *local, *result;

	local = concat_dir_and_file (current_dir, path);

	result = vfs_canon (local);
	g_free (local);
	return result;
    }

    /*
     * So we have path of following form:
     * /p1/p2#op/.././././p3#op/p4. Good luck.
     */
    {
	char *result = g_strdup (path);
	canonicalize_pathname (result);
        return result;
    }
}

static vfsid
vfs_ncs_getid (struct vfs_class *nvfs, const char *dir, struct vfs_stamping **par)
{
    vfsid nvfsid;
    char *dir1;

    dir1 = concat_dir_and_file (dir, "");
    nvfsid = (*nvfs->getid) (nvfs, dir1, par);
    g_free (dir1);
    return nvfsid;
}

static int
is_parent (struct vfs_class * nvfs, vfsid nvfsid, struct vfs_stamping *parent)
{
    struct vfs_stamping *stamp;

    for (stamp = parent; stamp; stamp = stamp->parent)
	if (stamp->v == nvfs && stamp->id == nvfsid)
	    break;

    return (stamp ? 1 : 0);
}

static void
_vfs_add_noncurrent_stamps (struct vfs_class *oldvfs, vfsid oldvfsid,
			    struct vfs_stamping *parent)
{
    struct vfs_class *nvfs, *n2vfs, *n3vfs;
    vfsid nvfsid, n2vfsid, n3vfsid;
    struct vfs_stamping *par, *stamp;
    int f;

    /* FIXME: As soon as we convert to multiple panels, this stuff
       has to change. It works like this: We do not time out the
       vfs's which are current in any panel and on the other
       side we add the old directory with all its parents which
       are not in any panel (if we find such one, we stop adding
       parents to the time-outing structure. */

    /* There are three directories we have to take care of: current_dir,
       current_panel->cwd and other_panel->cwd. Athough most of the time either
       current_dir and current_panel->cwd or current_dir and other_panel->cwd are the
       same, it's possible that all three are different -- Norbert */

    if (!current_panel)
	return;

    nvfs = vfs_get_class (current_dir);
    nvfsid = vfs_ncs_getid (nvfs, current_dir, &par);
    vfs_rmstamp (nvfs, nvfsid, 1);

    f = is_parent (oldvfs, oldvfsid, par);
    vfs_rm_parents (par);
    if ((nvfs == oldvfs && nvfsid == oldvfsid) || oldvfsid == (vfsid *) - 1
	|| f) {
	return;
    }

    if (get_current_type () == view_listing) {
	n2vfs = vfs_get_class (current_panel->cwd);
	n2vfsid = vfs_ncs_getid (n2vfs, current_panel->cwd, &par);
	f = is_parent (oldvfs, oldvfsid, par);
	vfs_rm_parents (par);
	if ((n2vfs == oldvfs && n2vfsid == oldvfsid) || f)
	    return;
    } else {
	n2vfs = (struct vfs_class *) -1;
	n2vfsid = (vfsid) - 1;
    }

    if (get_other_type () == view_listing) {
	n3vfs = vfs_get_class (other_panel->cwd);
	n3vfsid = vfs_ncs_getid (n3vfs, other_panel->cwd, &par);
	f = is_parent (oldvfs, oldvfsid, par);
	vfs_rm_parents (par);
	if ((n3vfs == oldvfs && n3vfsid == oldvfsid) || f)
	    return;
    } else {
	n3vfs = (struct vfs_class *) -1;
	n3vfsid = (vfsid) - 1;
    }

    if ((*oldvfs->nothingisopen) (oldvfsid)) {
#if 0				/* need setctl for this */
	if (oldvfs == &vfs_extfs_ops
	    && ((extfs_archive *) oldvfsid)->name == 0) {
	    /* Free the resources immediatly when we leave a mtools fs
	       ('cd a:') instead of waiting for the vfs-timeout */
	    (oldvfs->free) (oldvfsid);
	} else
#endif
	    vfs_addstamp (oldvfs, oldvfsid, parent);
	for (stamp = parent; stamp != NULL; stamp = stamp->parent) {
	    if ((stamp->v == nvfs && stamp->id == nvfsid)
		|| (stamp->v == n2vfs && stamp->id == n2vfsid)
		|| (stamp->v == n3vfs && stamp->id == n3vfsid)
		|| stamp->id == (vfsid) - 1
		|| !(*stamp->v->nothingisopen) (stamp->id))
		break;
#if 0
	    if (stamp->v == &vfs_extfs_ops
		&& ((extfs_archive *) stamp->id)->name == 0) {
		(stamp->v->free) (stamp->id);
		vfs_rmstamp (stamp->v, stamp->id, 0);
	    } else
#endif
		vfs_addstamp (stamp->v, stamp->id, stamp->parent);
	}
    }
}

void
vfs_add_noncurrent_stamps (struct vfs_class *oldvfs, vfsid oldvfsid,
			   struct vfs_stamping *parent)
{
    _vfs_add_noncurrent_stamps (oldvfs, oldvfsid, parent);
    vfs_rm_parents (parent);
}

static void
vfs_stamp_path (char *path)
{
    struct vfs_class *vfs;
    vfsid id;
    struct vfs_stamping *par, *stamp;
    
    vfs = vfs_get_class (path);
    id  = vfs_ncs_getid (vfs, path, &par);
    vfs_addstamp (vfs, id, par);
    
    for (stamp = par; stamp != NULL; stamp = stamp->parent) 
	vfs_addstamp (stamp->v, stamp->id, stamp->parent);
    vfs_rm_parents (par);
}

void
vfs_add_current_stamps (void)
{
    vfs_stamp_path (current_dir);

    if (current_panel) {
	if (get_current_type () == view_listing)
	    vfs_stamp_path (current_panel->cwd);
    }

    if (other_panel) {
	if (get_other_type () == view_listing)
	    vfs_stamp_path (other_panel->cwd);
    }
}

/*
 * VFS chdir.
 * Return 0 on success, -1 on failure.
 */
int
mc_chdir (char *path)
{
    char *new_dir, *new_dir_copy;
    struct vfs_class *old_vfs, *new_vfs;
    vfsid old_vfsid;
    struct vfs_stamping *parent;
    int result;

    new_dir = vfs_canon (path);
    new_vfs = vfs_get_class (new_dir);
    if (!new_vfs->chdir)
	return -1;

    /* new_vfs->chdir can write to the second argument, use a copy */
    new_dir_copy = g_strdup (new_dir);
    result = (*new_vfs->chdir) (new_vfs, new_dir_copy);
    g_free (new_dir_copy);

    if (result == -1) {
	errno = ferrno (new_vfs);
	g_free (new_dir);
	return -1;
    }

    old_vfsid = vfs_ncs_getid (current_vfs, current_dir, &parent);
    old_vfs = current_vfs;

    /* Actually change directory */
    g_free (current_dir);
    current_dir = new_dir;
    current_vfs = new_vfs;

    /* This function uses the new current_dir implicitly */
    vfs_add_noncurrent_stamps (old_vfs, old_vfsid, parent);

    /* Sometimes we assume no trailing slash on cwd */
    if (*current_dir) {
	char *p;
	p = strchr (current_dir, 0) - 1;
	if (*p == PATH_SEP && p > current_dir)
	    *p = 0;
    }

    return 0;
}

/* Return 1 is the current VFS class is local */
int
vfs_current_is_local (void)
{
    return (current_vfs->flags & VFSF_LOCAL) != 0;
}

/* Return flags of the VFS class of the given filename */
int
vfs_file_class_flags (const char *filename)
{
    struct vfs_class *vfs;
    char *fname;

    fname = vfs_canon (filename);
    vfs = vfs_get_class (fname);
    g_free (fname);
    return vfs->flags;
}

MC_NAMEOP (mkdir, (char *path, mode_t mode), (vfs, path, mode))
MC_NAMEOP (rmdir, (char *path), (vfs, path))
MC_NAMEOP (mknod, (char *path, int mode, int dev), (vfs, path, mode, dev))

#ifdef HAVE_MMAP
static struct mc_mmapping {
    caddr_t addr;
    void *vfs_info;
    struct vfs_class *vfs;
    struct mc_mmapping *next;
} *mc_mmaparray = NULL;

caddr_t
mc_mmap (caddr_t addr, size_t len, int prot, int flags, int fd, off_t offset)
{
    struct vfs_class *vfs;
    caddr_t result;
    struct mc_mmapping *mcm;

    if (fd == -1)
	return (caddr_t) -1;
    
    vfs = vfs_op (fd);
    result = vfs->mmap ? (*vfs->mmap)(vfs, addr, len, prot, flags, vfs_info (fd), offset) : (caddr_t)-1;
    if (result == (caddr_t)-1){
	errno = ferrno (vfs);
	return (caddr_t)-1;
    }
    mcm =g_new (struct mc_mmapping, 1);
    mcm->addr = result;
    mcm->vfs_info = vfs_info (fd);
    mcm->vfs = vfs;
    mcm->next = mc_mmaparray;
    mc_mmaparray = mcm;
    return result;
}

int
mc_munmap (caddr_t addr, size_t len)
{
    struct mc_mmapping *mcm, *mcm2 = NULL;
    
    for (mcm = mc_mmaparray; mcm != NULL; mcm2 = mcm, mcm = mcm->next){
        if (mcm->addr == addr){
            if (mcm2 == NULL)
            	mc_mmaparray = mcm->next;
            else
            	mcm2->next = mcm->next;
	    if (mcm->vfs->munmap)
	        (*mcm->vfs->munmap)(mcm->vfs, addr, len, mcm->vfs_info);
            g_free (mcm);
            return 0;
        }
    }
    return -1;
}

#endif

static char *
mc_def_getlocalcopy (struct vfs_class *vfs, const char *filename)
{
    char *tmp;
    int fdin, fdout, i;
    char buffer[8192];
    struct stat mystat;

    fdin = mc_open (filename, O_RDONLY | O_LINEAR);
    if (fdin == -1)
	return NULL;

    fdout = vfs_mkstemps (&tmp, "vfs", filename);

    if (fdout == -1)
	goto fail;
    while ((i = mc_read (fdin, buffer, sizeof (buffer))) > 0) {
	if (write (fdout, buffer, i) != i)
	    goto fail;
    }
    if (i == -1)
	goto fail;
    i = mc_close (fdin);
    fdin = -1;
    if (i == -1)
	goto fail;
    if (close (fdout) == -1)
	goto fail;

    if (mc_stat (filename, &mystat) != -1) {
	chmod (tmp, mystat.st_mode);
    }
    return tmp;

  fail:
    if (fdout)
	close (fdout);
    if (fdin)
	mc_close (fdin);
    g_free (tmp);
    return NULL;
}

char *
mc_getlocalcopy (const char *pathname)
{
    char *result;
    char *path = vfs_canon (pathname);
    struct vfs_class *vfs = vfs_get_class (path);    

    result = vfs->getlocalcopy ? (*vfs->getlocalcopy)(vfs, path) :
                                 mc_def_getlocalcopy (vfs, path);
    g_free (path);
    if (!result)
	errno = ferrno (vfs);
    return result;
}

static int
mc_def_ungetlocalcopy (struct vfs_class *vfs, const char *filename,
		       const char *local, int has_changed)
{
    int fdin = -1, fdout = -1, i;
    if (has_changed) {
	char buffer[8192];

	if (!vfs->write)
	    goto failed;

	fdin = open (local, O_RDONLY);
	if (fdin == -1)
	    goto failed;
	fdout = mc_open (filename, O_WRONLY | O_TRUNC);
	if (fdout == -1)
	    goto failed;
	while ((i = read (fdin, buffer, sizeof (buffer))) > 0) {
	    if (mc_write (fdout, buffer, i) != i)
		goto failed;
	}
	if (i == -1)
	    goto failed;

	if (close (fdin) == -1) {
	    fdin = -1;
	    goto failed;
	}
	fdin = -1;
	if (mc_close (fdout) == -1) {
	    fdout = -1;
	    goto failed;
	}
    }
    unlink (local);
    return 0;

  failed:
    message (1, _("Changes to file lost"), filename);
    if (fdout != -1)
	mc_close (fdout);
    if (fdin != -1)
	close (fdin);
    unlink (local);
    return -1;
}

int
mc_ungetlocalcopy (const char *pathname, char *local, int has_changed)
{
    int return_value = 0;
    char *path = vfs_canon (pathname);
    struct vfs_class *vfs = vfs_get_class (path);

    return_value = vfs->ungetlocalcopy ? 
            (*vfs->ungetlocalcopy)(vfs, path, local, has_changed) :
            mc_def_ungetlocalcopy (vfs, path, local, has_changed);
    g_free (path);
    g_free (local);
    return return_value;
}

/*
 * Hmm, as timeout is minute or so, do we need to care about usecs?
 */
static inline int
timeoutcmp (struct timeval *t1, struct timeval *t2)
{
    return ((t1->tv_sec < t2->tv_sec)
	    || ((t1->tv_sec == t2->tv_sec) && (t1->tv_usec <= t2->tv_usec)));
}

/* This is called from timeout handler with now = 0, or can be called
   with now = 1 to force freeing all filesystems that are not in use */

void
vfs_expire (int now)
{
    static int locked = 0;
    struct timeval time;
    struct vfs_stamping *stamp, *st;

    /* Avoid recursive invocation, e.g. when one of the free functions
       calls message */
    if (locked)
	return;
    locked = 1;

    gettimeofday (&time, NULL);
    time.tv_sec -= vfs_timeout;

    for (stamp = stamps; stamp != NULL;){
        if (now || (timeoutcmp (&stamp->time, &time))){
            st = stamp->next;
            (*stamp->v->free) (stamp->id);
	    vfs_rmstamp (stamp->v, stamp->id, 0);
	    stamp = st;
        } else
            stamp = stamp->next;
    }
    locked = 0;
}

void
vfs_timeout_handler (void)
{
    vfs_expire (0);
}

void
vfs_init (void)
{
    /* localfs needs to be the first one */
    init_localfs();
    /* fallback value for vfs_get_class() */
    localfs_class = vfs_list;

    init_extfs ();
    init_sfs ();
    init_tarfs ();
    init_cpiofs ();

#ifdef USE_EXT2FSLIB
    init_undelfs ();
#endif /* USE_EXT2FSLIB */

#ifdef USE_NETCODE
    tcp_init();
    init_ftpfs ();
    init_fish ();
#ifdef WITH_SMBFS
    init_smbfs ();
#endif /* WITH_SMBFS */
#ifdef WITH_MCFS
    init_mcfs ();
#endif /* WITH_SMBFS */
#endif /* USE_NETCODE */

    vfs_setup_wd ();
}

void
vfs_shut (void)
{
    struct vfs_stamping *stamp, *st;
    struct vfs_class *vfs;

    for (stamp = stamps, stamps = 0; stamp != NULL;){
	(*stamp->v->free)(stamp->id);
	st = stamp->next;
	g_free (stamp);
	stamp = st;
    }

    if (stamps)
	vfs_rmstamp (stamps->v, stamps->id, 1);
    
    if (current_dir)
	g_free (current_dir);

    for (vfs=vfs_list; vfs; vfs=vfs->next)
        if (vfs->done)
	     (*vfs->done) (vfs);

    g_slist_free (vfs_openfiles);
}

/*
 * These ones grab information from the VFS
 *  and handles them to an upper layer
 */
void
vfs_fill_names (void (*func)(char *))
{
    struct vfs_class *vfs;

    for (vfs=vfs_list; vfs; vfs=vfs->next)
        if (vfs->fill_names)
	    (*vfs->fill_names) (vfs, func);
}

/*
 * Returns vfs path corresponding to given url. If passed string is
 * not recognized as url, g_strdup(url) is returned.
 */
char *
vfs_translate_url (const char *url)
{
    if (strncmp (url, "ftp://", 6) == 0)
	return g_strconcat ("/#ftp:", url + 6, NULL);
    else if (strncmp (url, "a:", 2) == 0)
	return g_strdup ("/#a");
    else
	return g_strdup (url);
}


void
vfs_release_path (const char *dir)
{
    struct vfs_class *oldvfs;
    vfsid oldvfsid;
    struct vfs_stamping *parent;

    oldvfs = vfs_get_class (dir);
    oldvfsid = vfs_ncs_getid (oldvfs, dir, &parent);
    vfs_add_noncurrent_stamps (oldvfs, oldvfsid, parent);
}