server/change.c

   1 /*
   2  * Server-side change notification management
   3  *
   4  * Copyright (C) 1998 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "config.h"
  22 #include "wine/port.h"
  23
  24 #include <assert.h>
  25 #include <fcntl.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <signal.h>
  29 #include <sys/stat.h>
  30
  31 #include "windef.h"
  32
  33 #include "file.h"
  34 #include "handle.h"
  35 #include "thread.h"
  36 #include "request.h"
  37
  38 struct change
  39 {
  40     struct object  obj;      /* object header */
  41     struct fd     *fd;       /* file descriptor to the directory */
  42     struct list    entry;    /* entry in global change notifications list */
  43     int            subtree;  /* watch all the subtree */
  44     unsigned int   filter;   /* notification filter */
  45     long           notified; /* SIGIO counter */
  46     long           signaled; /* the file changed */
  47 };
  48
  49 static void change_dump( struct object *obj, int verbose );
  50 static int change_signaled( struct object *obj, struct thread *thread );
  51 static void change_destroy( struct object *obj );
  52
  53 static const struct object_ops change_ops =
  54 {
  55     sizeof(struct change),    /* size */
  56     change_dump,              /* dump */
  57     add_queue,                /* add_queue */
  58     remove_queue,             /* remove_queue */
  59     change_signaled,          /* signaled */
  60     no_satisfied,             /* satisfied */
  61     no_get_fd,                /* get_fd */
  62     change_destroy            /* destroy */
  63 };
  64
  65 static struct list change_list = LIST_INIT(change_list);
  66
  67 static void adjust_changes( int fd, unsigned int filter )
  68 {
  69 #ifdef F_NOTIFY
  70     unsigned int val;
  71     if ( 0 > fcntl( fd, F_SETSIG, SIGIO) )
  72         return;
  73
  74     val = DN_MULTISHOT;
  75     if( filter & FILE_NOTIFY_CHANGE_FILE_NAME )
  76         val |= DN_RENAME | DN_DELETE | DN_CREATE;
  77     if( filter & FILE_NOTIFY_CHANGE_DIR_NAME )
  78         val |= DN_RENAME | DN_DELETE | DN_CREATE;
  79     if( filter & FILE_NOTIFY_CHANGE_ATTRIBUTES )
  80         val |= DN_ATTRIB;
  81     if( filter & FILE_NOTIFY_CHANGE_SIZE )
  82         val |= DN_MODIFY;
  83     if( filter & FILE_NOTIFY_CHANGE_LAST_WRITE )
  84         val |= DN_MODIFY;
  85     if( filter & FILE_NOTIFY_CHANGE_LAST_ACCESS )
  86         val |= DN_ACCESS;
  87     if( filter & FILE_NOTIFY_CHANGE_CREATION )
  88         val |= DN_CREATE;
  89     if( filter & FILE_NOTIFY_CHANGE_SECURITY )
  90         val |= DN_ATTRIB;
  91     fcntl( fd, F_NOTIFY, val );
  92 #endif
  93 }
  94
  95 /* insert change in the global list */
  96 static inline void insert_change( struct change *change )
  97 {
  98     sigset_t sigset;
  99
 100     sigemptyset( &sigset );
 101     sigaddset( &sigset, SIGIO );
 102     sigprocmask( SIG_BLOCK, &sigset, NULL );
 103     list_add_head( &change_list, &change->entry );
 104     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 105 }
 106
 107 /* remove change from the global list */
 108 static inline void remove_change( struct change *change )
 109 {
 110     sigset_t sigset;
 111
 112     sigemptyset( &sigset );
 113     sigaddset( &sigset, SIGIO );
 114     sigprocmask( SIG_BLOCK, &sigset, NULL );
 115     list_remove( &change->entry );
 116     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 117 }
 118
 119 static struct change *create_change_notification( struct fd *fd, int subtree, unsigned int filter )
 120 {
 121     struct change *change;
 122     struct stat st;
 123     int unix_fd = get_unix_fd( fd );
 124
 125     if (fstat( unix_fd, &st ) == -1 || !S_ISDIR(st.st_mode))
 126     {
 127         set_error( STATUS_NOT_A_DIRECTORY );
 128         return NULL;
 129     }
 130
 131     if ((change = alloc_object( &change_ops )))
 132     {
 133         change->fd       = (struct fd *)grab_object( fd );
 134         change->subtree  = subtree;
 135         change->filter   = filter;
 136         change->notified = 0;
 137         change->signaled = 0;
 138         insert_change( change );
 139         adjust_changes( unix_fd, filter );
 140     }
 141     return change;
 142 }
 143
 144 static void change_dump( struct object *obj, int verbose )
 145 {
 146     struct change *change = (struct change *)obj;
 147     assert( obj->ops == &change_ops );
 148     fprintf( stderr, "Change notification fd=%p sub=%d filter=%08x\n",
 149              change->fd, change->subtree, change->filter );
 150 }
 151
 152 static int change_signaled( struct object *obj, struct thread *thread )
 153 {
 154     struct change *change = (struct change *)obj;
 155
 156     return change->signaled != 0;
 157 }
 158
 159 static void change_destroy( struct object *obj )
 160 {
 161     struct change *change = (struct change *)obj;
 162
 163     release_object( change->fd );
 164     remove_change( change );
 165 }
 166
 167 /* enter here directly from SIGIO signal handler */
 168 void do_change_notify( int unix_fd )
 169 {
 170     struct list *ptr;
 171
 172     /* FIXME: this is O(n) ... probably can be improved */
 173     LIST_FOR_EACH( ptr, &change_list )
 174     {
 175         struct change *change = LIST_ENTRY( ptr, struct change, entry );
 176         if (get_unix_fd( change->fd ) != unix_fd) continue;
 177         interlocked_xchg_add( &change->notified, 1 );
 178         break;
 179     }
 180 }
 181
 182 /* SIGIO callback, called synchronously with the poll loop */
 183 void sigio_callback(void)
 184 {
 185     struct list *ptr;
 186
 187     LIST_FOR_EACH( ptr, &change_list )
 188     {
 189         struct change *change = LIST_ENTRY( ptr, struct change, entry );
 190         long count = interlocked_xchg( &change->notified, 0 );
 191         if (count)
 192         {
 193             change->signaled += count;
 194             if (change->signaled == count)  /* was it 0? */
 195                 wake_up( &change->obj, 0 );
 196         }
 197     }
 198 }
 199
 200 /* create a change notification */
 201 DECL_HANDLER(create_change_notification)
 202 {
 203     struct change *change;
 204     struct file *file;
 205     struct fd *fd;
 206
 207     if (!(file = get_file_obj( current->process, req->handle, 0 ))) return;
 208     fd = get_obj_fd( (struct object *)file );
 209     release_object( file );
 210     if (!fd) return;
 211
 212     if ((change = create_change_notification( fd, req->subtree, req->filter )))
 213     {
 214         reply->handle = alloc_handle( current->process, change,
 215                                       STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE, 0 );
 216         release_object( change );
 217     }
 218     release_object( fd );
 219 }
 220
 221 /* move to the next change notification */
 222 DECL_HANDLER(next_change_notification)
 223 {
 224     struct change *change;
 225
 226     if ((change = (struct change *)get_handle_obj( current->process, req->handle,
 227                                                    0, &change_ops )))
 228     {
 229         if (change->signaled > 0) change->signaled--;
 230         release_object( change );
 231     }
 232 }