server/object.c

   1 /*
   2  * Server-side objects
   3  * These are the server equivalent of K32OBJ
   4  *
   5  * Copyright (C) 1998 Alexandre Julliard
   6  */
   7
   8 #include <assert.h>
   9 #include <limits.h>
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <unistd.h>
  14
  15 #include "thread.h"
  16 #include "unicode.h"
  17
  18
  19 struct object_name
  20 {
  21     struct object_name *next;
  22     struct object_name *prev;
  23     struct object      *obj;
  24     size_t              len;
  25     WCHAR               name[1];
  26 };
  27
  28 #define NAME_HASH_SIZE 37
  29
  30 static struct object_name *names[NAME_HASH_SIZE];
  31
  32 #ifdef DEBUG_OBJECTS
  33 static struct object *first;
  34
  35 void dump_objects(void)
  36 {
  37     struct object *ptr = first;
  38     while (ptr)
  39     {
  40         fprintf( stderr, "%p:%d: ", ptr, ptr->refcount );
  41         ptr->ops->dump( ptr, 1 );
  42         ptr = ptr->next;
  43     }
  44 }
  45 #endif
  46
  47 /*****************************************************************/
  48
  49 /* malloc replacement */
  50 void *mem_alloc( size_t size )
  51 {
  52     void *ptr = malloc( size );
  53     if (ptr) memset( ptr, 0x55, size );
  54     else if (current) set_error( STATUS_NO_MEMORY );
  55     return ptr;
  56 }
  57
  58 /* duplicate a block of memory */
  59 void *memdup( const void *data, size_t len )
  60 {
  61     void *ptr = mem_alloc( len );
  62     if (ptr) memcpy( ptr, data, len );
  63     return ptr;
  64 }
  65
  66
  67 /*****************************************************************/
  68
  69 static int get_name_hash( const WCHAR *name, size_t len )
  70 {
  71     WCHAR hash = 0;
  72     while (len--) hash ^= *name++;
  73     return hash % NAME_HASH_SIZE;
  74 }
  75
  76 /* allocate a name for an object */
  77 static struct object_name *alloc_name( const WCHAR *name, size_t len )
  78 {
  79     struct object_name *ptr;
  80
  81     if ((ptr = mem_alloc( sizeof(*ptr) + len * sizeof(ptr->name[0]) )))
  82     {
  83         ptr->len = len;
  84         memcpy( ptr->name, name, len * sizeof(ptr->name[0]) );
  85         ptr->name[len] = 0;
  86     }
  87     return ptr;
  88 }
  89
  90 /* free the name of an object */
  91 static void free_name( struct object *obj )
  92 {
  93     struct object_name *ptr = obj->name;
  94     if (ptr->next) ptr->next->prev = ptr->prev;
  95     if (ptr->prev) ptr->prev->next = ptr->next;
  96     else
  97     {
  98         int hash;
  99         for (hash = 0; hash < NAME_HASH_SIZE; hash++)
 100             if (names[hash] == ptr)
 101             {
 102                 names[hash] = ptr->next;
 103                 break;
 104             }
 105     }
 106     free( ptr );
 107 }
 108
 109 /* set the name of an existing object */
 110 static void set_object_name( struct object *obj, struct object_name *ptr )
 111 {
 112     int hash = get_name_hash( ptr->name, ptr->len );
 113
 114     if ((ptr->next = names[hash]) != NULL) ptr->next->prev = ptr;
 115     ptr->obj = obj;
 116     ptr->prev = NULL;
 117     names[hash] = ptr;
 118     assert( !obj->name );
 119     obj->name = ptr;
 120 }
 121
 122 /* allocate and initialize an object */
 123 /* if the function fails the fd is closed */
 124 void *alloc_object( const struct object_ops *ops, int fd )
 125 {
 126     struct object *obj = mem_alloc( ops->size );
 127     if (obj)
 128     {
 129         obj->refcount = 1;
 130         obj->fd       = fd;
 131         obj->select   = -1;
 132         obj->ops      = ops;
 133         obj->head     = NULL;
 134         obj->tail     = NULL;
 135         obj->name     = NULL;
 136         if ((fd != -1) && (add_select_user( obj ) == -1))
 137         {
 138             close( fd );
 139             free( obj );
 140             return NULL;
 141         }
 142 #ifdef DEBUG_OBJECTS
 143         obj->prev = NULL;
 144         if ((obj->next = first) != NULL) obj->next->prev = obj;
 145         first = obj;
 146 #endif
 147         return obj;
 148     }
 149     if (fd != -1) close( fd );
 150     return NULL;
 151 }
 152
 153 void *create_named_object( const struct object_ops *ops, const WCHAR *name, size_t len )
 154 {
 155     struct object *obj;
 156     struct object_name *name_ptr;
 157
 158     if (!name || !len) return alloc_object( ops, -1 );
 159     if (!(name_ptr = alloc_name( name, len ))) return NULL;
 160
 161     if ((obj = find_object( name_ptr->name, name_ptr->len )))
 162     {
 163         free( name_ptr );  /* we no longer need it */
 164         if (obj->ops == ops)
 165         {
 166             set_error( STATUS_OBJECT_NAME_COLLISION );
 167             return obj;
 168         }
 169         set_error( STATUS_OBJECT_TYPE_MISMATCH );
 170         return NULL;
 171     }
 172     if ((obj = alloc_object( ops, -1 )))
 173     {
 174         set_object_name( obj, name_ptr );
 175         clear_error();
 176     }
 177     else free( name_ptr );
 178     return obj;
 179 }
 180
 181 /* dump the name of an object to stderr */
 182 void dump_object_name( struct object *obj )
 183 {
 184     if (!obj->name) fprintf( stderr, "name=\"\"" );
 185     else
 186     {
 187         fprintf( stderr, "name=L\"" );
 188         dump_strW( obj->name->name, strlenW(obj->name->name), stderr, "\"\"" );
 189         fputc( '\"', stderr );
 190     }
 191 }
 192
 193 /* grab an object (i.e. increment its refcount) and return the object */
 194 struct object *grab_object( void *ptr )
 195 {
 196     struct object *obj = (struct object *)ptr;
 197     assert( obj->refcount < INT_MAX );
 198     obj->refcount++;
 199     return obj;
 200 }
 201
 202 /* release an object (i.e. decrement its refcount) */
 203 void release_object( void *ptr )
 204 {
 205     struct object *obj = (struct object *)ptr;
 206     assert( obj->refcount );
 207     if (!--obj->refcount)
 208     {
 209         /* if the refcount is 0, nobody can be in the wait queue */
 210         assert( !obj->head );
 211         assert( !obj->tail );
 212         obj->ops->destroy( obj );
 213         if (obj->name) free_name( obj );
 214         if (obj->select != -1) remove_select_user( obj );
 215         if (obj->fd != -1) close( obj->fd );
 216 #ifdef DEBUG_OBJECTS
 217         if (obj->next) obj->next->prev = obj->prev;
 218         if (obj->prev) obj->prev->next = obj->next;
 219         else first = obj->next;
 220         memset( obj, 0xaa, obj->ops->size );
 221 #endif
 222         free( obj );
 223     }
 224 }
 225
 226 /* find an object by its name; the refcount is incremented */
 227 struct object *find_object( const WCHAR *name, size_t len )
 228 {
 229     struct object_name *ptr;
 230     if (!name || !len) return NULL;
 231     for (ptr = names[ get_name_hash( name, len ) ]; ptr; ptr = ptr->next)
 232     {
 233         if (ptr->len != len) continue;
 234         if (!memcmp( ptr->name, name, len*sizeof(WCHAR) )) return grab_object( ptr->obj );
 235     }
 236     return NULL;
 237 }
 238
 239 /* functions for unimplemented/default object operations */
 240
 241 int no_add_queue( struct object *obj, struct wait_queue_entry *entry )
 242 {
 243     set_error( STATUS_OBJECT_TYPE_MISMATCH );
 244     return 0;
 245 }
 246
 247 int no_satisfied( struct object *obj, struct thread *thread )
 248 {
 249     return 0;  /* not abandoned */
 250 }
 251
 252 int no_read_fd( struct object *obj )
 253 {
 254     set_error( STATUS_OBJECT_TYPE_MISMATCH );
 255     return -1;
 256 }
 257
 258 int no_write_fd( struct object *obj )
 259 {
 260     set_error( STATUS_OBJECT_TYPE_MISMATCH );
 261     return -1;
 262 }
 263
 264 int no_flush( struct object *obj )
 265 {
 266     set_error( STATUS_OBJECT_TYPE_MISMATCH );
 267     return 0;
 268 }
 269
 270 int no_get_file_info( struct object *obj, struct get_file_info_request *info )
 271 {
 272     set_error( STATUS_OBJECT_TYPE_MISMATCH );
 273     return 0;
 274 }
 275
 276 void no_destroy( struct object *obj )
 277 {
 278 }
 279
 280 /* default add_queue() routine for objects that poll() on an fd */
 281 int default_poll_add_queue( struct object *obj, struct wait_queue_entry *entry )
 282 {
 283     if (!obj->head)  /* first on the queue */
 284         set_select_events( obj, obj->ops->get_poll_events( obj ) );
 285     add_queue( obj, entry );
 286     return 1;
 287 }
 288
 289 /* default remove_queue() routine for objects that poll() on an fd */
 290 void default_poll_remove_queue( struct object *obj, struct wait_queue_entry *entry )
 291 {
 292     grab_object(obj);
 293     remove_queue( obj, entry );
 294     if (!obj->head)  /* last on the queue is gone */
 295         set_select_events( obj, 0 );
 296     release_object( obj );
 297 }
 298
 299 /* default signaled() routine for objects that poll() on an fd */
 300 int default_poll_signaled( struct object *obj, struct thread *thread )
 301 {
 302     int events = obj->ops->get_poll_events( obj );
 303
 304     if (check_select_events( obj->fd, events ))
 305     {
 306         /* stop waiting on select() if we are signaled */
 307         set_select_events( obj, 0 );
 308         return 1;
 309     }
 310     /* restart waiting on select() if we are no longer signaled */
 311     if (obj->head) set_select_events( obj, events );
 312     return 0;
 313 }
 314
 315 /* default handler for poll() events */
 316 void default_poll_event( struct object *obj, int event )
 317 {
 318     /* an error occurred, stop polling this fd to avoid busy-looping */
 319     if (event & (POLLERR | POLLHUP)) set_select_events( obj, -1 );
 320     wake_up( obj, 0 );
 321 }