server/object.c

   1 /*
   2  * Server-side objects
   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 <limits.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30
  31 #include "thread.h"
  32 #include "unicode.h"
  33
  34
  35 struct object_name
  36 {
  37     struct object_name *next;
  38     struct object_name *prev;
  39     struct object      *obj;
  40     size_t              len;
  41     WCHAR               name[1];
  42 };
  43
  44 #define NAME_HASH_SIZE 37
  45
  46 static struct object_name *names[NAME_HASH_SIZE];
  47
  48 #ifdef DEBUG_OBJECTS
  49 static struct object *first;
  50
  51 void dump_objects(void)
  52 {
  53     struct object *ptr = first;
  54     while (ptr)
  55     {
  56         fprintf( stderr, "%p:%d: ", ptr, ptr->refcount );
  57         ptr->ops->dump( ptr, 1 );
  58         ptr = ptr->next;
  59     }
  60 }
  61 #endif
  62
  63 /*****************************************************************/
  64
  65 /* malloc replacement */
  66 void *mem_alloc( size_t size )
  67 {
  68     void *ptr = malloc( size );
  69     if (ptr) memset( ptr, 0x55, size );
  70     else set_error( STATUS_NO_MEMORY );
  71     return ptr;
  72 }
  73
  74 /* duplicate a block of memory */
  75 void *memdup( const void *data, size_t len )
  76 {
  77     void *ptr = malloc( len );
  78     if (ptr) memcpy( ptr, data, len );
  79     else set_error( STATUS_NO_MEMORY );
  80     return ptr;
  81 }
  82
  83
  84 /*****************************************************************/
  85
  86 static int get_name_hash( const WCHAR *name, size_t len )
  87 {
  88     WCHAR hash = 0;
  89     len /= sizeof(WCHAR);
  90     while (len--) hash ^= *name++;
  91     return hash % NAME_HASH_SIZE;
  92 }
  93
  94 /* allocate a name for an object */
  95 static struct object_name *alloc_name( const WCHAR *name, size_t len )
  96 {
  97     struct object_name *ptr;
  98
  99     if ((ptr = mem_alloc( sizeof(*ptr) + len - sizeof(ptr->name) )))
 100     {
 101         ptr->len = len;
 102         memcpy( ptr->name, name, len );
 103     }
 104     return ptr;
 105 }
 106
 107 /* free the name of an object */
 108 static void free_name( struct object *obj )
 109 {
 110     struct object_name *ptr = obj->name;
 111     if (ptr->next) ptr->next->prev = ptr->prev;
 112     if (ptr->prev) ptr->prev->next = ptr->next;
 113     else
 114     {
 115         int hash;
 116         for (hash = 0; hash < NAME_HASH_SIZE; hash++)
 117             if (names[hash] == ptr)
 118             {
 119                 names[hash] = ptr->next;
 120                 break;
 121             }
 122     }
 123     free( ptr );
 124 }
 125
 126 /* set the name of an existing object */
 127 static void set_object_name( struct object *obj, struct object_name *ptr )
 128 {
 129     int hash = get_name_hash( ptr->name, ptr->len );
 130
 131     if ((ptr->next = names[hash]) != NULL) ptr->next->prev = ptr;
 132     ptr->obj = obj;
 133     ptr->prev = NULL;
 134     names[hash] = ptr;
 135     assert( !obj->name );
 136     obj->name = ptr;
 137 }
 138
 139 /* allocate and initialize an object */
 140 /* if the function fails the fd is closed */
 141 void *alloc_object( const struct object_ops *ops, int fd )
 142 {
 143     struct object *obj = mem_alloc( ops->size );
 144     if (obj)
 145     {
 146         obj->refcount = 1;
 147         obj->fd       = fd;
 148         obj->select   = -1;
 149         obj->ops      = ops;
 150         obj->head     = NULL;
 151         obj->tail     = NULL;
 152         obj->name     = NULL;
 153         if ((fd != -1) && (add_select_user( obj ) == -1))
 154         {
 155             close( fd );
 156             free( obj );
 157             return NULL;
 158         }
 159 #ifdef DEBUG_OBJECTS
 160         obj->prev = NULL;
 161         if ((obj->next = first) != NULL) obj->next->prev = obj;
 162         first = obj;
 163 #endif
 164         return obj;
 165     }
 166     if (fd != -1) close( fd );
 167     return NULL;
 168 }
 169
 170 void *create_named_object( const struct object_ops *ops, const WCHAR *name, size_t len )
 171 {
 172     struct object *obj;
 173     struct object_name *name_ptr;
 174
 175     if (!name || !len) return alloc_object( ops, -1 );
 176     if (!(name_ptr = alloc_name( name, len ))) return NULL;
 177
 178     if ((obj = find_object( name_ptr->name, name_ptr->len )))
 179     {
 180         free( name_ptr );  /* we no longer need it */
 181         if (obj->ops == ops)
 182         {
 183             set_error( STATUS_OBJECT_NAME_COLLISION );
 184             return obj;
 185         }
 186         set_error( STATUS_OBJECT_TYPE_MISMATCH );
 187         return NULL;
 188     }
 189     if ((obj = alloc_object( ops, -1 )))
 190     {
 191         set_object_name( obj, name_ptr );
 192         clear_error();
 193     }
 194     else free( name_ptr );
 195     return obj;
 196 }
 197
 198 /* dump the name of an object to stderr */
 199 void dump_object_name( struct object *obj )
 200 {
 201     if (!obj->name) fprintf( stderr, "name=\"\"" );
 202     else
 203     {
 204         fprintf( stderr, "name=L\"" );
 205         dump_strW( obj->name->name, obj->name->len/sizeof(WCHAR), stderr, "\"\"" );
 206         fputc( '\"', stderr );
 207     }
 208 }
 209
 210 /* grab an object (i.e. increment its refcount) and return the object */
 211 struct object *grab_object( void *ptr )
 212 {
 213     struct object *obj = (struct object *)ptr;
 214     assert( obj->refcount < INT_MAX );
 215     obj->refcount++;
 216     return obj;
 217 }
 218
 219 /* release an object (i.e. decrement its refcount) */
 220 void release_object( void *ptr )
 221 {
 222     struct object *obj = (struct object *)ptr;
 223     assert( obj->refcount );
 224     if (!--obj->refcount)
 225     {
 226         /* if the refcount is 0, nobody can be in the wait queue */
 227         assert( !obj->head );
 228         assert( !obj->tail );
 229         obj->ops->destroy( obj );
 230         if (obj->name) free_name( obj );
 231         if (obj->select != -1) remove_select_user( obj );
 232         if (obj->fd != -1) close( obj->fd );
 233 #ifdef DEBUG_OBJECTS
 234         if (obj->next) obj->next->prev = obj->prev;
 235         if (obj->prev) obj->prev->next = obj->next;
 236         else first = obj->next;
 237         memset( obj, 0xaa, obj->ops->size );
 238 #endif
 239         free( obj );
 240     }
 241 }
 242
 243 /* find an object by its name; the refcount is incremented */
 244 struct object *find_object( const WCHAR *name, size_t len )
 245 {
 246     struct object_name *ptr;
 247
 248     if (!name || !len) return NULL;
 249     for (ptr = names[ get_name_hash( name, len ) ]; ptr; ptr = ptr->next)
 250     {
 251         if (ptr->len != len) continue;
 252         if (!memcmp( ptr->name, name, len )) return grab_object( ptr->obj );
 253     }
 254     return NULL;
 255 }
 256
 257 /* functions for unimplemented/default object operations */
 258
 259 int no_add_queue( struct object *obj, struct wait_queue_entry *entry )
 260 {
 261     set_error( STATUS_OBJECT_TYPE_MISMATCH );
 262     return 0;
 263 }
 264
 265 int no_satisfied( struct object *obj, struct thread *thread )
 266 {
 267     return 0;  /* not abandoned */
 268 }
 269
 270 int no_get_fd( struct object *obj )
 271 {
 272     set_error( STATUS_OBJECT_TYPE_MISMATCH );
 273     return -1;
 274 }
 275
 276 int no_flush( struct object *obj )
 277 {
 278     set_error( STATUS_OBJECT_TYPE_MISMATCH );
 279     return 0;
 280 }
 281
 282 int no_get_file_info( struct object *obj, struct get_file_info_reply *info, int *flags )
 283 {
 284     set_error( STATUS_OBJECT_TYPE_MISMATCH );
 285     *flags = 0;
 286     return FD_TYPE_INVALID;
 287 }
 288
 289 void no_destroy( struct object *obj )
 290 {
 291 }
 292
 293 /* default add_queue() routine for objects that poll() on an fd */
 294 int default_poll_add_queue( struct object *obj, struct wait_queue_entry *entry )
 295 {
 296     if (!obj->head)  /* first on the queue */
 297         set_select_events( obj, obj->ops->get_poll_events( obj ) );
 298     add_queue( obj, entry );
 299     return 1;
 300 }
 301
 302 /* default remove_queue() routine for objects that poll() on an fd */
 303 void default_poll_remove_queue( struct object *obj, struct wait_queue_entry *entry )
 304 {
 305     grab_object(obj);
 306     remove_queue( obj, entry );
 307     if (!obj->head)  /* last on the queue is gone */
 308         set_select_events( obj, 0 );
 309     release_object( obj );
 310 }
 311
 312 /* default signaled() routine for objects that poll() on an fd */
 313 int default_poll_signaled( struct object *obj, struct thread *thread )
 314 {
 315     int events = obj->ops->get_poll_events( obj );
 316
 317     if (check_select_events( obj->fd, events ))
 318     {
 319         /* stop waiting on select() if we are signaled */
 320         set_select_events( obj, 0 );
 321         return 1;
 322     }
 323     /* restart waiting on select() if we are no longer signaled */
 324     if (obj->head) set_select_events( obj, events );
 325     return 0;
 326 }
 327
 328 /* default handler for poll() events */
 329 void default_poll_event( struct object *obj, int event )
 330 {
 331     /* an error occurred, stop polling this fd to avoid busy-looping */
 332     if (event & (POLLERR | POLLHUP)) set_select_events( obj, -1 );
 333     wake_up( obj, 0 );
 334 }