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 #ifdef linux
  39 #ifndef F_NOTIFY
  40 #define F_NOTIFY 1026
  41 #define DN_ACCESS       0x00000001      /* File accessed */
  42 #define DN_MODIFY       0x00000002      /* File modified */
  43 #define DN_CREATE       0x00000004      /* File created */
  44 #define DN_DELETE       0x00000008      /* File removed */
  45 #define DN_RENAME       0x00000010      /* File renamed */
  46 #define DN_ATTRIB       0x00000020      /* File changed attibutes */
  47 #define DN_MULTISHOT    0x80000000      /* Don't remove notifier */
  48 #endif
  49 #endif
  50
  51 struct change
  52 {
  53     struct object  obj;      /* object header */
  54     struct fd     *fd;       /* file descriptor to the directory */
  55     struct list    entry;    /* entry in global change notifications list */
  56     int            subtree;  /* watch all the subtree */
  57     unsigned int   filter;   /* notification filter */
  58     long           notified; /* SIGIO counter */
  59     long           signaled; /* the file changed */
  60 };
  61
  62 static void change_dump( struct object *obj, int verbose );
  63 static int change_signaled( struct object *obj, struct thread *thread );
  64 static void change_destroy( struct object *obj );
  65
  66 static const struct object_ops change_ops =
  67 {
  68     sizeof(struct change),    /* size */
  69     change_dump,              /* dump */
  70     add_queue,                /* add_queue */
  71     remove_queue,             /* remove_queue */
  72     change_signaled,          /* signaled */
  73     no_satisfied,             /* satisfied */
  74     no_get_fd,                /* get_fd */
  75     change_destroy            /* destroy */
  76 };
  77
  78 static struct list change_list = LIST_INIT(change_list);
  79
  80 static void adjust_changes( int fd, unsigned int filter )
  81 {
  82 #if defined(F_SETSIG) && defined(F_NOTIFY)
  83     unsigned int val;
  84     if ( 0 > fcntl( fd, F_SETSIG, SIGIO) )
  85         return;
  86
  87     val = DN_MULTISHOT;
  88     if( filter & FILE_NOTIFY_CHANGE_FILE_NAME )
  89         val |= DN_RENAME | DN_DELETE | DN_CREATE;
  90     if( filter & FILE_NOTIFY_CHANGE_DIR_NAME )
  91         val |= DN_RENAME | DN_DELETE | DN_CREATE;
  92     if( filter & FILE_NOTIFY_CHANGE_ATTRIBUTES )
  93         val |= DN_ATTRIB;
  94     if( filter & FILE_NOTIFY_CHANGE_SIZE )
  95         val |= DN_MODIFY;
  96     if( filter & FILE_NOTIFY_CHANGE_LAST_WRITE )
  97         val |= DN_MODIFY;
  98     if( filter & FILE_NOTIFY_CHANGE_LAST_ACCESS )
  99         val |= DN_ACCESS;
 100     if( filter & FILE_NOTIFY_CHANGE_CREATION )
 101         val |= DN_CREATE;
 102     if( filter & FILE_NOTIFY_CHANGE_SECURITY )
 103         val |= DN_ATTRIB;
 104     fcntl( fd, F_NOTIFY, val );
 105 #endif
 106 }
 107
 108 /* insert change in the global list */
 109 static inline void insert_change( struct change *change )
 110 {
 111     sigset_t sigset;
 112
 113     sigemptyset( &sigset );
 114     sigaddset( &sigset, SIGIO );
 115     sigprocmask( SIG_BLOCK, &sigset, NULL );
 116     list_add_head( &change_list, &change->entry );
 117     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 118 }
 119
 120 /* remove change from the global list */
 121 static inline void remove_change( struct change *change )
 122 {
 123     sigset_t sigset;
 124
 125     sigemptyset( &sigset );
 126     sigaddset( &sigset, SIGIO );
 127     sigprocmask( SIG_BLOCK, &sigset, NULL );
 128     list_remove( &change->entry );
 129     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 130 }
 131
 132 static struct change *create_change_notification( struct fd *fd, int subtree, unsigned int filter )
 133 {
 134     struct change *change;
 135     struct stat st;
 136     int unix_fd = get_unix_fd( fd );
 137
 138     if (fstat( unix_fd, &st ) == -1 || !S_ISDIR(st.st_mode))
 139     {
 140         set_error( STATUS_NOT_A_DIRECTORY );
 141         return NULL;
 142     }
 143
 144     if ((change = alloc_object( &change_ops )))
 145     {
 146         change->fd       = (struct fd *)grab_object( fd );
 147         change->subtree  = subtree;
 148         change->filter   = filter;
 149         change->notified = 0;
 150         change->signaled = 0;
 151         insert_change( change );
 152         adjust_changes( unix_fd, filter );
 153     }
 154     return change;
 155 }
 156
 157 static void change_dump( struct object *obj, int verbose )
 158 {
 159     struct change *change = (struct change *)obj;
 160     assert( obj->ops == &change_ops );
 161     fprintf( stderr, "Change notification fd=%p sub=%d filter=%08x\n",
 162              change->fd, change->subtree, change->filter );
 163 }
 164
 165 static int change_signaled( struct object *obj, struct thread *thread )
 166 {
 167     struct change *change = (struct change *)obj;
 168
 169     return change->signaled != 0;
 170 }
 171
 172 static void change_destroy( struct object *obj )
 173 {
 174     struct change *change = (struct change *)obj;
 175
 176     release_object( change->fd );
 177     remove_change( change );
 178 }
 179
 180 /* enter here directly from SIGIO signal handler */
 181 void do_change_notify( int unix_fd )
 182 {
 183     struct list *ptr;
 184
 185     /* FIXME: this is O(n) ... probably can be improved */
 186     LIST_FOR_EACH( ptr, &change_list )
 187     {
 188         struct change *change = LIST_ENTRY( ptr, struct change, entry );
 189         if (get_unix_fd( change->fd ) != unix_fd) continue;
 190         interlocked_xchg_add( &change->notified, 1 );
 191         break;
 192     }
 193 }
 194
 195 /* SIGIO callback, called synchronously with the poll loop */
 196 void sigio_callback(void)
 197 {
 198     struct list *ptr;
 199
 200     LIST_FOR_EACH( ptr, &change_list )
 201     {
 202         struct change *change = LIST_ENTRY( ptr, struct change, entry );
 203         long count = interlocked_xchg( &change->notified, 0 );
 204         if (count)
 205         {
 206             change->signaled += count;
 207             if (change->signaled == count)  /* was it 0? */
 208                 wake_up( &change->obj, 0 );
 209         }
 210     }
 211 }
 212
 213 /* create a change notification */
 214 DECL_HANDLER(create_change_notification)
 215 {
 216     struct change *change;
 217     struct file *file;
 218     struct fd *fd;
 219
 220     if (!(file = get_file_obj( current->process, req->handle, 0 ))) return;
 221     fd = get_obj_fd( (struct object *)file );
 222     release_object( file );
 223     if (!fd) return;
 224
 225     if ((change = create_change_notification( fd, req->subtree, req->filter )))
 226     {
 227         reply->handle = alloc_handle( current->process, change,
 228                                       STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE, 0 );
 229         release_object( change );
 230     }
 231     release_object( fd );
 232 }
 233
 234 /* move to the next change notification */
 235 DECL_HANDLER(next_change_notification)
 236 {
 237     struct change *change;
 238
 239     if ((change = (struct change *)get_handle_obj( current->process, req->handle,
 240                                                    0, &change_ops )))
 241     {
 242         if (change->signaled > 0) change->signaled--;
 243         release_object( change );
 244     }
 245 }