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