Sweden-Number/server/change.c

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/*
* Server-side change notification management
*
* Copyright (C) 1998 Alexandre Julliard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "config.h"
#include "wine/port.h"
#include <assert.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include "windef.h"
#include "file.h"
#include "handle.h"
#include "thread.h"
#include "request.h"
#include "list.h"
struct change
{
struct object obj; /* object header */
struct fd *fd; /* file descriptor to the directory */
struct list entry; /* entry in global change notifications list */
int subtree; /* watch all the subtree */
unsigned int filter; /* notification filter */
long notified; /* SIGIO counter */
long signaled; /* the file changed */
};
static void change_dump( struct object *obj, int verbose );
static int change_signaled( struct object *obj, struct thread *thread );
static void change_destroy( struct object *obj );
static const struct object_ops change_ops =
{
sizeof(struct change), /* size */
change_dump, /* dump */
add_queue, /* add_queue */
remove_queue, /* remove_queue */
change_signaled, /* signaled */
no_satisfied, /* satisfied */
no_get_fd, /* get_fd */
change_destroy /* destroy */
};
static struct list change_list = LIST_INIT(change_list);
static void adjust_changes( int fd, unsigned int filter )
{
#ifdef F_NOTIFY
unsigned int val;
if ( 0 > fcntl( fd, F_SETSIG, SIGIO) )
return;
val = DN_MULTISHOT;
if( filter & FILE_NOTIFY_CHANGE_FILE_NAME )
val |= DN_RENAME | DN_DELETE | DN_CREATE;
if( filter & FILE_NOTIFY_CHANGE_DIR_NAME )
val |= DN_RENAME | DN_DELETE | DN_CREATE;
if( filter & FILE_NOTIFY_CHANGE_ATTRIBUTES )
val |= DN_ATTRIB;
if( filter & FILE_NOTIFY_CHANGE_SIZE )
val |= DN_MODIFY;
if( filter & FILE_NOTIFY_CHANGE_LAST_WRITE )
val |= DN_MODIFY;
if( filter & FILE_NOTIFY_CHANGE_SECURITY )
val |= DN_ATTRIB;
fcntl( fd, F_NOTIFY, val );
#endif
}
/* insert change in the global list */
static inline void insert_change( struct change *change )
{
sigset_t sigset;
sigemptyset( &sigset );
sigaddset( &sigset, SIGIO );
sigprocmask( SIG_BLOCK, &sigset, NULL );
list_add_head( &change_list, &change->entry );
sigprocmask( SIG_UNBLOCK, &sigset, NULL );
}
/* remove change from the global list */
static inline void remove_change( struct change *change )
{
sigset_t sigset;
sigemptyset( &sigset );
sigaddset( &sigset, SIGIO );
sigprocmask( SIG_BLOCK, &sigset, NULL );
list_remove( &change->entry );
sigprocmask( SIG_UNBLOCK, &sigset, NULL );
}
static struct change *create_change_notification( struct fd *fd, int subtree, unsigned int filter )
{
struct change *change;
if ((change = alloc_object( &change_ops )))
{
change->fd = (struct fd *)grab_object( fd );
change->subtree = subtree;
change->filter = filter;
change->notified = 0;
change->signaled = 0;
insert_change( change );
adjust_changes( get_unix_fd(fd), filter );
}
return change;
}
static void change_dump( struct object *obj, int verbose )
{
struct change *change = (struct change *)obj;
assert( obj->ops == &change_ops );
fprintf( stderr, "Change notification fd=%p sub=%d filter=%08x\n",
change->fd, change->subtree, change->filter );
}
static int change_signaled( struct object *obj, struct thread *thread )
{
struct change *change = (struct change *)obj;
return change->signaled != 0;
}
static void change_destroy( struct object *obj )
{
struct change *change = (struct change *)obj;
release_object( change->fd );
remove_change( change );
}
/* enter here directly from SIGIO signal handler */
void do_change_notify( int unix_fd )
{
struct list *ptr;
/* FIXME: this is O(n) ... probably can be improved */
LIST_FOR_EACH( ptr, &change_list )
{
struct change *change = LIST_ENTRY( ptr, struct change, entry );
if (get_unix_fd( change->fd ) != unix_fd) continue;
interlocked_xchg_add( &change->notified, 1 );
break;
}
}
/* SIGIO callback, called synchronously with the poll loop */
void sigio_callback(void)
{
struct list *ptr;
LIST_FOR_EACH( ptr, &change_list )
{
struct change *change = LIST_ENTRY( ptr, struct change, entry );
long count = interlocked_xchg( &change->notified, 0 );
if (count)
{
change->signaled += count;
if (change->signaled == count) /* was it 0? */
wake_up( &change->obj, 0 );
}
}
}
/* create a change notification */
DECL_HANDLER(create_change_notification)
{
struct change *change;
struct file *file;
struct fd *fd;
if (!(file = get_file_obj( current->process, req->handle, 0 ))) return;
fd = get_obj_fd( (struct object *)file );
release_object( file );
if (!fd) return;
if ((change = create_change_notification( fd, req->subtree, req->filter )))
{
reply->handle = alloc_handle( current->process, change,
STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE, 0 );
release_object( change );
}
release_object( fd );
}
/* move to the next change notification */
DECL_HANDLER(next_change_notification)
{
struct change *change;
if ((change = (struct change *)get_handle_obj( current->process, req->handle,
0, &change_ops )))
{
if (change->signaled > 0) change->signaled--;
release_object( change );
}
}