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
  14 #include "winerror.h"
  15 #include "thread.h"
  16 #include "unicode.h"
  17
  18 int debug_level = 0;
  19
  20 struct object_name
  21 {
  22     struct object_name *next;
  23     struct object_name *prev;
  24     struct object      *obj;
  25     size_t              len;
  26     WCHAR               name[1];
  27 };
  28
  29 #define NAME_HASH_SIZE 37
  30
  31 static struct object_name *names[NAME_HASH_SIZE];
  32
  33 #ifdef DEBUG_OBJECTS
  34 static struct object *first;
  35
  36 void dump_objects(void)
  37 {
  38     struct object *ptr = first;
  39     while (ptr)
  40     {
  41         fprintf( stderr, "%p:%d: ", ptr, ptr->refcount );
  42         ptr->ops->dump( ptr, 1 );
  43         ptr = ptr->next;
  44     }
  45 }
  46 #endif
  47
  48 /*****************************************************************/
  49
  50 /* malloc replacement */
  51 void *mem_alloc( size_t size )
  52 {
  53     void *ptr = malloc( size );
  54     if (ptr) memset( ptr, 0x55, size );
  55     else if (current) set_error( ERROR_OUTOFMEMORY );
  56     return ptr;
  57 }
  58
  59 /* duplicate a block of memory */
  60 void *memdup( const void *data, size_t len )
  61 {
  62     void *ptr = mem_alloc( len );
  63     if (ptr) memcpy( ptr, data, len );
  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     while (len--) hash ^= *name++;
  74     return hash % NAME_HASH_SIZE;
  75 }
  76
  77 /* allocate a name for an object */
  78 static struct object_name *alloc_name( const WCHAR *name, size_t len )
  79 {
  80     struct object_name *ptr;
  81
  82     if ((ptr = mem_alloc( sizeof(*ptr) + len * sizeof(ptr->name[0]) )))
  83     {
  84         ptr->len = len;
  85         memcpy( ptr->name, name, len * sizeof(ptr->name[0]) );
  86         ptr->name[len] = 0;
  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 void *alloc_object( const struct object_ops *ops )
 125 {
 126     struct object *obj = mem_alloc( ops->size );
 127     if (obj)
 128     {
 129         obj->refcount = 1;
 130         obj->ops      = ops;
 131         obj->head     = NULL;
 132         obj->tail     = NULL;
 133         obj->name     = NULL;
 134 #ifdef DEBUG_OBJECTS
 135         obj->prev = NULL;
 136         if ((obj->next = first) != NULL) obj->next->prev = obj;
 137         first = obj;
 138 #endif
 139     }
 140     return obj;
 141 }
 142
 143 void *create_named_object( const struct object_ops *ops, const WCHAR *name, size_t len )
 144 {
 145     struct object *obj;
 146     struct object_name *name_ptr;
 147
 148     if (!name || !len) return alloc_object( ops );
 149     if (!(name_ptr = alloc_name( name, len ))) return NULL;
 150
 151     if ((obj = find_object( name_ptr->name, name_ptr->len )))
 152     {
 153         free( name_ptr );  /* we no longer need it */
 154         if (obj->ops == ops)
 155         {
 156             set_error( ERROR_ALREADY_EXISTS );
 157             return obj;
 158         }
 159         set_error( ERROR_INVALID_HANDLE );
 160         return NULL;
 161     }
 162     if ((obj = alloc_object( ops )))
 163     {
 164         set_object_name( obj, name_ptr );
 165         clear_error();
 166     }
 167     else free( name_ptr );
 168     return obj;
 169 }
 170
 171 /* dump the name of an object to stderr */
 172 void dump_object_name( struct object *obj )
 173 {
 174     if (!obj->name) fprintf( stderr, "name=\"\"" );
 175     else
 176     {
 177         fprintf( stderr, "name=L\"" );
 178         dump_strW( obj->name->name, strlenW(obj->name->name), stderr, "\"\"" );
 179         fputc( '\"', stderr );
 180     }
 181 }
 182
 183 /* grab an object (i.e. increment its refcount) and return the object */
 184 struct object *grab_object( void *ptr )
 185 {
 186     struct object *obj = (struct object *)ptr;
 187     assert( obj->refcount < INT_MAX );
 188     obj->refcount++;
 189     return obj;
 190 }
 191
 192 /* release an object (i.e. decrement its refcount) */
 193 void release_object( void *ptr )
 194 {
 195     struct object *obj = (struct object *)ptr;
 196     assert( obj->refcount );
 197     if (!--obj->refcount)
 198     {
 199         /* if the refcount is 0, nobody can be in the wait queue */
 200         assert( !obj->head );
 201         assert( !obj->tail );
 202         if (obj->name) free_name( obj );
 203 #ifdef DEBUG_OBJECTS
 204         if (obj->next) obj->next->prev = obj->prev;
 205         if (obj->prev) obj->prev->next = obj->next;
 206         else first = obj->next;
 207 #endif
 208         obj->ops->destroy( obj );
 209         memset( obj, 0xaa, obj->ops->size );
 210         free( obj );
 211     }
 212 }
 213
 214 /* find an object by its name; the refcount is incremented */
 215 struct object *find_object( const WCHAR *name, size_t len )
 216 {
 217     struct object_name *ptr;
 218     if (!name || !len) return NULL;
 219     for (ptr = names[ get_name_hash( name, len ) ]; ptr; ptr = ptr->next)
 220     {
 221         if (ptr->len != len) continue;
 222         if (!memcmp( ptr->name, name, len*sizeof(WCHAR) )) return grab_object( ptr->obj );
 223     }
 224     return NULL;
 225 }
 226
 227 /* functions for unimplemented object operations */
 228
 229 int no_add_queue( struct object *obj, struct wait_queue_entry *entry )
 230 {
 231     set_error( ERROR_INVALID_HANDLE );
 232     return 0;
 233 }
 234
 235 int no_satisfied( struct object *obj, struct thread *thread )
 236 {
 237     return 0;  /* not abandoned */
 238 }
 239
 240 int no_read_fd( struct object *obj )
 241 {
 242     set_error( ERROR_INVALID_HANDLE );
 243     return -1;
 244 }
 245
 246 int no_write_fd( struct object *obj )
 247 {
 248     set_error( ERROR_INVALID_HANDLE );
 249     return -1;
 250 }
 251
 252 int no_flush( struct object *obj )
 253 {
 254     set_error( ERROR_INVALID_HANDLE );
 255     return 0;
 256 }
 257
 258 int no_get_file_info( struct object *obj, struct get_file_info_request *info )
 259 {
 260     set_error( ERROR_INVALID_HANDLE );
 261     return 0;
 262 }
 263
 264 void no_destroy( struct object *obj )
 265 {
 266 }
 267
 268 void default_select_event( int event, void *private )
 269 {
 270     struct object *obj = (struct object *)private;
 271     assert( obj );
 272     wake_up( obj, 0 );
 273 }