server/change.c

   1 /*
   2  * Server-side change notification management
   3  *
   4  * Copyright (C) 1998 Alexandre Julliard
   5  * Copyright (C) 2006 Mike McCormack
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include "config.h"
  23 #include "wine/port.h"
  24
  25 #include <assert.h>
  26 #include <fcntl.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <signal.h>
  30 #include <sys/stat.h>
  31
  32 #include "ntstatus.h"
  33 #define WIN32_NO_STATUS
  34 #include "windef.h"
  35
  36 #include "file.h"
  37 #include "handle.h"
  38 #include "thread.h"
  39 #include "request.h"
  40 #include "winternl.h"
  41
  42 #ifdef linux
  43 #ifndef F_NOTIFY
  44 #define F_NOTIFY 1026
  45 #define DN_ACCESS       0x00000001      /* File accessed */
  46 #define DN_MODIFY       0x00000002      /* File modified */
  47 #define DN_CREATE       0x00000004      /* File created */
  48 #define DN_DELETE       0x00000008      /* File removed */
  49 #define DN_RENAME       0x00000010      /* File renamed */
  50 #define DN_ATTRIB       0x00000020      /* File changed attibutes */
  51 #define DN_MULTISHOT    0x80000000      /* Don't remove notifier */
  52 #endif
  53 #endif
  54
  55 struct dir
  56 {
  57     struct object  obj;      /* object header */
  58     struct fd     *fd;       /* file descriptor to the directory */
  59     struct list    entry;    /* entry in global change notifications list */
  60     struct event  *event;
  61     unsigned int   filter;   /* notification filter */
  62     int            notified; /* SIGIO counter */
  63     long           signaled; /* the file changed */
  64 };
  65
  66 static struct fd *dir_get_fd( struct object *obj );
  67 static unsigned int dir_map_access( struct object *obj, unsigned int access );
  68 static void dir_dump( struct object *obj, int verbose );
  69 static void dir_destroy( struct object *obj );
  70 static int dir_signaled( struct object *obj, struct thread *thread );
  71
  72 static const struct object_ops dir_ops =
  73 {
  74     sizeof(struct dir),       /* size */
  75     dir_dump,                 /* dump */
  76     add_queue,                /* add_queue */
  77     remove_queue,             /* remove_queue */
  78     dir_signaled,             /* signaled */
  79     no_satisfied,             /* satisfied */
  80     no_signal,                /* signal */
  81     dir_get_fd,               /* get_fd */
  82     dir_map_access,           /* map_access */
  83     no_lookup_name,           /* lookup_name */
  84     no_close_handle,          /* close_handle */
  85     dir_destroy               /* destroy */
  86 };
  87
  88 static int dir_get_poll_events( struct fd *fd );
  89 static int dir_get_info( struct fd *fd );
  90
  91 static const struct fd_ops dir_fd_ops =
  92 {
  93     dir_get_poll_events,      /* get_poll_events */
  94     default_poll_event,       /* poll_event */
  95     no_flush,                 /* flush */
  96     dir_get_info,             /* get_file_info */
  97     default_fd_queue_async,   /* queue_async */
  98     default_fd_cancel_async   /* cancel_async */
  99 };
 100
 101 static struct list change_list = LIST_INIT(change_list);
 102
 103 static void adjust_changes( int fd, unsigned int filter )
 104 {
 105 #if defined(F_SETSIG) && defined(F_NOTIFY)
 106     unsigned int val;
 107     if ( 0 > fcntl( fd, F_SETSIG, SIGIO) )
 108         return;
 109
 110     val = DN_MULTISHOT;
 111     if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 112         val |= DN_RENAME | DN_DELETE | DN_CREATE;
 113     if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 114         val |= DN_RENAME | DN_DELETE | DN_CREATE;
 115     if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 116         val |= DN_ATTRIB;
 117     if (filter & FILE_NOTIFY_CHANGE_SIZE)
 118         val |= DN_MODIFY;
 119     if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 120         val |= DN_MODIFY;
 121     if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 122         val |= DN_ACCESS;
 123     if (filter & FILE_NOTIFY_CHANGE_CREATION)
 124         val |= DN_CREATE;
 125     if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 126         val |= DN_ATTRIB;
 127     fcntl( fd, F_NOTIFY, val );
 128 #endif
 129 }
 130
 131 /* insert change in the global list */
 132 static inline void insert_change( struct dir *dir )
 133 {
 134     sigset_t sigset;
 135
 136     sigemptyset( &sigset );
 137     sigaddset( &sigset, SIGIO );
 138     sigprocmask( SIG_BLOCK, &sigset, NULL );
 139     list_add_head( &change_list, &dir->entry );
 140     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 141 }
 142
 143 /* remove change from the global list */
 144 static inline void remove_change( struct dir *dir )
 145 {
 146     sigset_t sigset;
 147
 148     sigemptyset( &sigset );
 149     sigaddset( &sigset, SIGIO );
 150     sigprocmask( SIG_BLOCK, &sigset, NULL );
 151     list_remove( &dir->entry );
 152     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 153 }
 154
 155 struct object *create_dir_obj( struct fd *fd )
 156 {
 157     struct dir *dir;
 158
 159     dir = alloc_object( &dir_ops );
 160     if (!dir)
 161         return NULL;
 162
 163     dir->event = NULL;
 164     dir->filter = 0;
 165     dir->notified = 0;
 166     dir->signaled = 0;
 167     grab_object( fd );
 168     dir->fd = fd;
 169     set_fd_user( fd, &dir_fd_ops, &dir->obj );
 170
 171     return &dir->obj;
 172 }
 173
 174 static void dir_dump( struct object *obj, int verbose )
 175 {
 176     struct dir *dir = (struct dir *)obj;
 177     assert( obj->ops == &dir_ops );
 178     fprintf( stderr, "Dirfile fd=%p event=%p filter=%08x\n",
 179              dir->fd, dir->event, dir->filter );
 180 }
 181
 182 static int dir_signaled( struct object *obj, struct thread *thread )
 183 {
 184     struct dir *dir = (struct dir *)obj;
 185     assert (obj->ops == &dir_ops);
 186     return (dir->event == NULL) && dir->signaled;
 187 }
 188
 189 /* enter here directly from SIGIO signal handler */
 190 void do_change_notify( int unix_fd )
 191 {
 192     struct list *ptr;
 193
 194     /* FIXME: this is O(n) ... probably can be improved */
 195     LIST_FOR_EACH( ptr, &change_list )
 196     {
 197         struct dir *dir = LIST_ENTRY( ptr, struct dir, entry );
 198         if (get_unix_fd( dir->fd ) != unix_fd) continue;
 199         interlocked_xchg_add( &dir->notified, 1 );
 200         break;
 201     }
 202 }
 203
 204 /* SIGIO callback, called synchronously with the poll loop */
 205 void sigio_callback(void)
 206 {
 207     struct list *ptr;
 208
 209     LIST_FOR_EACH( ptr, &change_list )
 210     {
 211         struct dir *dir = LIST_ENTRY( ptr, struct dir, entry );
 212         long count = interlocked_xchg( &dir->notified, 0 );
 213         if (count)
 214         {
 215             dir->signaled += count;
 216             if (dir->signaled == count)  /* was it 0? */
 217             {
 218                 if (dir->event)
 219                     set_event( dir->event );
 220                 else
 221                     wake_up( &dir->obj, 0 );
 222             }
 223         }
 224     }
 225 }
 226
 227 static struct fd *dir_get_fd( struct object *obj )
 228 {
 229     struct dir *dir = (struct dir *)obj;
 230     assert( obj->ops == &dir_ops );
 231     return (struct fd *)grab_object( dir->fd );
 232 }
 233
 234 static unsigned int dir_map_access( struct object *obj, unsigned int access )
 235 {
 236     if (access & GENERIC_READ)    access |= FILE_GENERIC_READ;
 237     if (access & GENERIC_WRITE)   access |= FILE_GENERIC_WRITE;
 238     if (access & GENERIC_EXECUTE) access |= FILE_GENERIC_EXECUTE;
 239     if (access & GENERIC_ALL)     access |= FILE_ALL_ACCESS;
 240     return access & ~(GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE | GENERIC_ALL);
 241 }
 242
 243 static void dir_destroy( struct object *obj )
 244 {
 245     struct dir *dir = (struct dir *)obj;
 246     assert (obj->ops == &dir_ops);
 247
 248     if (dir->filter)
 249         remove_change( dir );
 250
 251     if (dir->event)
 252     {
 253         set_event( dir->event );
 254         release_object( dir->event );
 255     }
 256     release_object( dir->fd );
 257 }
 258
 259 static struct dir *
 260 get_dir_obj( struct process *process, obj_handle_t handle, unsigned int access )
 261 {
 262     return (struct dir *)get_handle_obj( process, handle, access, &dir_ops );
 263 }
 264
 265 static int dir_get_poll_events( struct fd *fd )
 266 {
 267     return 0;
 268 }
 269
 270 static int dir_get_info( struct fd *fd )
 271 {
 272     return 0;
 273 }
 274
 275 /* enable change notifications for a directory */
 276 DECL_HANDLER(read_directory_changes)
 277 {
 278     struct event *event = NULL;
 279     struct dir *dir;
 280
 281     if (!req->filter)
 282     {
 283         set_error(STATUS_INVALID_PARAMETER);
 284         return;
 285     }
 286
 287     dir = get_dir_obj( current->process, req->handle, 0 );
 288     if (!dir)
 289         return;
 290
 291     /* possibly send changes through an event flag */
 292     if (req->event)
 293     {
 294         event = get_event_obj( current->process, req->event, EVENT_MODIFY_STATE );
 295         if (!event)
 296             goto end;
 297     }
 298
 299     /* discard the current data, and move onto the next event */
 300     if (dir->event) release_object( dir->event );
 301     dir->event = event;
 302
 303     /* assign it once */
 304     if (!dir->filter)
 305     {
 306         insert_change( dir );
 307         dir->filter = req->filter;
 308     }
 309
 310     /* remove any notifications */
 311     if (dir->signaled>0)
 312         dir->signaled--;
 313
 314     adjust_changes( get_unix_fd( dir->fd ), dir->filter );
 315
 316     set_error(STATUS_PENDING);
 317
 318 end:
 319     release_object( dir );
 320 }