server/handle.c

   1 /*
   2  * Server-side handle management
   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20
  21 #include "config.h"
  22 #include "wine/port.h"
  23
  24 #include <assert.h>
  25 #include <limits.h>
  26 #include <string.h>
  27 #include <stdarg.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30
  31 #include "ntstatus.h"
  32 #define WIN32_NO_STATUS
  33 #include "windef.h"
  34 #include "winternl.h"
  35
  36 #include "handle.h"
  37 #include "process.h"
  38 #include "thread.h"
  39 #include "request.h"
  40
  41 struct handle_entry
  42 {
  43     struct object *ptr;       /* object */
  44     unsigned int   access;    /* access rights */
  45 };
  46
  47 struct handle_table
  48 {
  49     struct object        obj;         /* object header */
  50     struct process      *process;     /* process owning this table */
  51     int                  count;       /* number of allocated entries */
  52     int                  last;        /* last used entry */
  53     int                  free;        /* first entry that may be free */
  54     struct handle_entry *entries;     /* handle entries */
  55 };
  56
  57 static struct handle_table *global_table;
  58
  59 /* reserved handle access rights */
  60 #define RESERVED_SHIFT         26
  61 #define RESERVED_INHERIT       (HANDLE_FLAG_INHERIT << RESERVED_SHIFT)
  62 #define RESERVED_CLOSE_PROTECT (HANDLE_FLAG_PROTECT_FROM_CLOSE << RESERVED_SHIFT)
  63 #define RESERVED_ALL           (RESERVED_INHERIT | RESERVED_CLOSE_PROTECT)
  64
  65 #define MIN_HANDLE_ENTRIES  32
  66
  67
  68 /* handle to table index conversion */
  69
  70 /* handles are a multiple of 4 under NT; handle 0 is not used */
  71 inline static obj_handle_t index_to_handle( int index )
  72 {
  73     return (obj_handle_t)((unsigned long)(index + 1) << 2);
  74 }
  75 inline static int handle_to_index( obj_handle_t handle )
  76 {
  77     return ((unsigned long)handle >> 2) - 1;
  78 }
  79
  80 /* global handle conversion */
  81
  82 #define HANDLE_OBFUSCATOR 0x544a4def
  83
  84 inline static int handle_is_global( obj_handle_t handle)
  85 {
  86     return ((unsigned long)handle ^ HANDLE_OBFUSCATOR) < 0x10000;
  87 }
  88 inline static obj_handle_t handle_local_to_global( obj_handle_t handle )
  89 {
  90     if (!handle) return 0;
  91     return (obj_handle_t)((unsigned long)handle ^ HANDLE_OBFUSCATOR);
  92 }
  93 inline static obj_handle_t handle_global_to_local( obj_handle_t handle )
  94 {
  95     return (obj_handle_t)((unsigned long)handle ^ HANDLE_OBFUSCATOR);
  96 }
  97
  98
  99 static void handle_table_dump( struct object *obj, int verbose );
 100 static void handle_table_destroy( struct object *obj );
 101
 102 static const struct object_ops handle_table_ops =
 103 {
 104     sizeof(struct handle_table),     /* size */
 105     handle_table_dump,               /* dump */
 106     no_add_queue,                    /* add_queue */
 107     NULL,                            /* remove_queue */
 108     NULL,                            /* signaled */
 109     NULL,                            /* satisfied */
 110     no_signal,                       /* signal */
 111     no_get_fd,                       /* get_fd */
 112     no_map_access,                   /* map_access */
 113     no_lookup_name,                  /* lookup_name */
 114     no_close_handle,                 /* close_handle */
 115     handle_table_destroy             /* destroy */
 116 };
 117
 118 /* dump a handle table */
 119 static void handle_table_dump( struct object *obj, int verbose )
 120 {
 121     int i;
 122     struct handle_table *table = (struct handle_table *)obj;
 123     struct handle_entry *entry = table->entries;
 124
 125     assert( obj->ops == &handle_table_ops );
 126
 127     fprintf( stderr, "Handle table last=%d count=%d process=%p\n",
 128              table->last, table->count, table->process );
 129     if (!verbose) return;
 130     entry = table->entries;
 131     for (i = 0; i <= table->last; i++, entry++)
 132     {
 133         if (!entry->ptr) continue;
 134         fprintf( stderr, "    %p: %p %08x ",
 135                  index_to_handle(i), entry->ptr, entry->access );
 136         entry->ptr->ops->dump( entry->ptr, 0 );
 137     }
 138 }
 139
 140 /* destroy a handle table */
 141 static void handle_table_destroy( struct object *obj )
 142 {
 143     int i;
 144     struct handle_table *table = (struct handle_table *)obj;
 145     struct handle_entry *entry;
 146
 147     assert( obj->ops == &handle_table_ops );
 148
 149     /* first notify all objects that handles are being closed */
 150     if (table->process)
 151     {
 152         for (i = 0, entry = table->entries; i <= table->last; i++, entry++)
 153         {
 154             struct object *obj = entry->ptr;
 155             if (obj) obj->ops->close_handle( obj, table->process, index_to_handle(i) );
 156         }
 157     }
 158
 159     for (i = 0, entry = table->entries; i <= table->last; i++, entry++)
 160     {
 161         struct object *obj = entry->ptr;
 162         entry->ptr = NULL;
 163         if (obj) release_object( obj );
 164     }
 165     free( table->entries );
 166 }
 167
 168 /* allocate a new handle table */
 169 struct handle_table *alloc_handle_table( struct process *process, int count )
 170 {
 171     struct handle_table *table;
 172
 173     if (count < MIN_HANDLE_ENTRIES) count = MIN_HANDLE_ENTRIES;
 174     if (!(table = alloc_object( &handle_table_ops )))
 175         return NULL;
 176     table->process = process;
 177     table->count   = count;
 178     table->last    = -1;
 179     table->free    = 0;
 180     if ((table->entries = mem_alloc( count * sizeof(*table->entries) ))) return table;
 181     release_object( table );
 182     return NULL;
 183 }
 184
 185 /* grow a handle table */
 186 static int grow_handle_table( struct handle_table *table )
 187 {
 188     struct handle_entry *new_entries;
 189     int count = table->count;
 190
 191     if (count >= INT_MAX / 2) return 0;
 192     count *= 2;
 193     if (!(new_entries = realloc( table->entries, count * sizeof(struct handle_entry) )))
 194     {
 195         set_error( STATUS_NO_MEMORY );
 196         return 0;
 197     }
 198     table->entries = new_entries;
 199     table->count   = count;
 200     return 1;
 201 }
 202
 203 /* allocate the first free entry in the handle table */
 204 static obj_handle_t alloc_entry( struct handle_table *table, void *obj, unsigned int access )
 205 {
 206     struct handle_entry *entry = table->entries + table->free;
 207     int i;
 208
 209     for (i = table->free; i <= table->last; i++, entry++) if (!entry->ptr) goto found;
 210     if (i >= table->count)
 211     {
 212         if (!grow_handle_table( table )) return 0;
 213         entry = table->entries + i;  /* the entries may have moved */
 214     }
 215     table->last = i;
 216  found:
 217     table->free = i + 1;
 218     entry->ptr    = grab_object( obj );
 219     entry->access = access;
 220     return index_to_handle(i);
 221 }
 222
 223 /* allocate a handle for an object, incrementing its refcount */
 224 /* return the handle, or 0 on error */
 225 obj_handle_t alloc_handle( struct process *process, void *ptr, unsigned int access, unsigned int attr )
 226 {
 227     struct object *obj = ptr;
 228
 229     access = obj->ops->map_access( obj, access );
 230     access &= ~RESERVED_ALL;
 231     if (attr & OBJ_INHERIT) access |= RESERVED_INHERIT;
 232     if (!process->handles)
 233     {
 234         set_error( STATUS_NO_MEMORY );
 235         return 0;
 236     }
 237     return alloc_entry( process->handles, obj, access );
 238 }
 239
 240 /* allocate a global handle for an object, incrementing its refcount */
 241 /* return the handle, or 0 on error */
 242 static obj_handle_t alloc_global_handle( void *obj, unsigned int access )
 243 {
 244     if (!global_table)
 245     {
 246         if (!(global_table = (struct handle_table *)alloc_handle_table( NULL, 0 )))
 247             return 0;
 248         make_object_static( &global_table->obj );
 249     }
 250     return handle_local_to_global( alloc_entry( global_table, obj, access ));
 251 }
 252
 253 /* return a handle entry, or NULL if the handle is invalid */
 254 static struct handle_entry *get_handle( struct process *process, obj_handle_t handle )
 255 {
 256     struct handle_table *table = process->handles;
 257     struct handle_entry *entry;
 258     int index;
 259
 260     if (handle_is_global(handle))
 261     {
 262         handle = handle_global_to_local(handle);
 263         table = global_table;
 264     }
 265     if (!table) goto error;
 266     index = handle_to_index( handle );
 267     if (index < 0) goto error;
 268     if (index > table->last) goto error;
 269     entry = table->entries + index;
 270     if (!entry->ptr) goto error;
 271     return entry;
 272
 273  error:
 274     set_error( STATUS_INVALID_HANDLE );
 275     return NULL;
 276 }
 277
 278 /* attempt to shrink a table */
 279 static void shrink_handle_table( struct handle_table *table )
 280 {
 281     struct handle_entry *entry = table->entries + table->last;
 282     struct handle_entry *new_entries;
 283     int count = table->count;
 284
 285     while (table->last >= 0)
 286     {
 287         if (entry->ptr) break;
 288         table->last--;
 289         entry--;
 290     }
 291     if (table->last >= count / 4) return;  /* no need to shrink */
 292     if (count < MIN_HANDLE_ENTRIES * 2) return;  /* too small to shrink */
 293     count /= 2;
 294     if (!(new_entries = realloc( table->entries, count * sizeof(*new_entries) ))) return;
 295     table->count   = count;
 296     table->entries = new_entries;
 297 }
 298
 299 /* copy the handle table of the parent process */
 300 /* return 1 if OK, 0 on error */
 301 struct handle_table *copy_handle_table( struct process *process, struct process *parent )
 302 {
 303     struct handle_table *parent_table = parent->handles;
 304     struct handle_table *table;
 305     int i;
 306
 307     assert( parent_table );
 308     assert( parent_table->obj.ops == &handle_table_ops );
 309
 310     if (!(table = (struct handle_table *)alloc_handle_table( process, parent_table->count )))
 311         return NULL;
 312
 313     if ((table->last = parent_table->last) >= 0)
 314     {
 315         struct handle_entry *ptr = table->entries;
 316         memcpy( ptr, parent_table->entries, (table->last + 1) * sizeof(struct handle_entry) );
 317         for (i = 0; i <= table->last; i++, ptr++)
 318         {
 319             if (!ptr->ptr) continue;
 320             if (ptr->access & RESERVED_INHERIT) grab_object( ptr->ptr );
 321             else ptr->ptr = NULL; /* don't inherit this entry */
 322         }
 323     }
 324     /* attempt to shrink the table */
 325     shrink_handle_table( table );
 326     return table;
 327 }
 328
 329 /* close a handle and decrement the refcount of the associated object */
 330 /* return 1 if OK, 0 on error */
 331 int close_handle( struct process *process, obj_handle_t handle )
 332 {
 333     struct handle_table *table;
 334     struct handle_entry *entry;
 335     struct object *obj;
 336
 337     if (!(entry = get_handle( process, handle ))) return 0;
 338     if (entry->access & RESERVED_CLOSE_PROTECT)
 339     {
 340         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 341         return 0;
 342     }
 343     obj = entry->ptr;
 344     if (!obj->ops->close_handle( obj, process, handle ))
 345     {
 346         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 347         return 0;
 348     }
 349     entry->ptr = NULL;
 350     table = handle_is_global(handle) ? global_table : process->handles;
 351     if (entry < table->entries + table->free) table->free = entry - table->entries;
 352     if (entry == table->entries + table->last) shrink_handle_table( table );
 353     release_object( obj );
 354     return 1;
 355 }
 356
 357 /* retrieve the object corresponding to one of the magic pseudo-handles */
 358 static inline struct object *get_magic_handle( obj_handle_t handle )
 359 {
 360     switch((unsigned long)handle)
 361     {
 362         case 0xfffffffe:  /* current thread pseudo-handle */
 363             return &current->obj;
 364         case 0x7fffffff:  /* current process pseudo-handle */
 365         case 0xffffffff:  /* current process pseudo-handle */
 366             return (struct object *)current->process;
 367         default:
 368             return NULL;
 369     }
 370 }
 371
 372 /* retrieve the object corresponding to a handle, incrementing its refcount */
 373 struct object *get_handle_obj( struct process *process, obj_handle_t handle,
 374                                unsigned int access, const struct object_ops *ops )
 375 {
 376     struct handle_entry *entry;
 377     struct object *obj;
 378
 379     if (!(obj = get_magic_handle( handle )))
 380     {
 381         if (!(entry = get_handle( process, handle ))) return NULL;
 382         if ((entry->access & access) != access)
 383         {
 384             set_error( STATUS_ACCESS_DENIED );
 385             return NULL;
 386         }
 387         obj = entry->ptr;
 388     }
 389     if (ops && (obj->ops != ops))
 390     {
 391         set_error( STATUS_OBJECT_TYPE_MISMATCH );  /* not the right type */
 392         return NULL;
 393     }
 394     return grab_object( obj );
 395 }
 396
 397 /* retrieve the access rights of a given handle */
 398 unsigned int get_handle_access( struct process *process, obj_handle_t handle )
 399 {
 400     struct handle_entry *entry;
 401
 402     if (get_magic_handle( handle )) return ~0U;  /* magic handles have all access rights */
 403     if (!(entry = get_handle( process, handle ))) return 0;
 404     return entry->access;
 405 }
 406
 407 /* find the first inherited handle of the given type */
 408 /* this is needed for window stations and desktops (don't ask...) */
 409 obj_handle_t find_inherited_handle( struct process *process, const struct object_ops *ops )
 410 {
 411     struct handle_table *table = process->handles;
 412     struct handle_entry *ptr;
 413     int i;
 414
 415     if (!table) return 0;
 416
 417     for (i = 0, ptr = table->entries; i <= table->last; i++, ptr++)
 418     {
 419         if (!ptr->ptr) continue;
 420         if (ptr->ptr->ops != ops) continue;
 421         if (ptr->access & RESERVED_INHERIT) return index_to_handle(i);
 422     }
 423     return 0;
 424 }
 425
 426 /* get/set the handle reserved flags */
 427 /* return the old flags (or -1 on error) */
 428 static int set_handle_flags( struct process *process, obj_handle_t handle, int mask, int flags )
 429 {
 430     struct handle_entry *entry;
 431     unsigned int old_access;
 432
 433     if (get_magic_handle( handle ))
 434     {
 435         /* we can retrieve but not set info for magic handles */
 436         if (mask) set_error( STATUS_ACCESS_DENIED );
 437         return 0;
 438     }
 439     if (!(entry = get_handle( process, handle ))) return -1;
 440     old_access = entry->access;
 441     mask  = (mask << RESERVED_SHIFT) & RESERVED_ALL;
 442     flags = (flags << RESERVED_SHIFT) & mask;
 443     entry->access = (entry->access & ~mask) | flags;
 444     return (old_access & RESERVED_ALL) >> RESERVED_SHIFT;
 445 }
 446
 447 /* duplicate a handle */
 448 obj_handle_t duplicate_handle( struct process *src, obj_handle_t src_handle, struct process *dst,
 449                                unsigned int access, unsigned int attr, unsigned int options )
 450 {
 451     obj_handle_t res;
 452     struct object *obj = get_handle_obj( src, src_handle, 0, NULL );
 453
 454     if (!obj) return 0;
 455     if (options & DUP_HANDLE_SAME_ACCESS)
 456     {
 457         struct handle_entry *entry = get_handle( src, src_handle );
 458         if (entry)
 459             access = entry->access;
 460         else  /* pseudo-handle, give it full access */
 461         {
 462             access = STANDARD_RIGHTS_ALL | SPECIFIC_RIGHTS_ALL;
 463             clear_error();
 464         }
 465     }
 466     access &= ~RESERVED_ALL;
 467     if (options & DUP_HANDLE_MAKE_GLOBAL)
 468         res = alloc_global_handle( obj, access );
 469     else
 470         res = alloc_handle( dst, obj, access, attr );
 471     release_object( obj );
 472     return res;
 473 }
 474
 475 /* open a new handle to an existing object */
 476 obj_handle_t open_object( const struct namespace *namespace, const struct unicode_str *name,
 477                           const struct object_ops *ops, unsigned int access, unsigned int attr )
 478 {
 479     obj_handle_t handle = 0;
 480     struct object *obj = find_object( namespace, name, attr );
 481     if (obj)
 482     {
 483         if (ops && obj->ops != ops)
 484             set_error( STATUS_OBJECT_TYPE_MISMATCH );
 485         else
 486             handle = alloc_handle( current->process, obj, access, attr );
 487         release_object( obj );
 488     }
 489     else
 490         set_error( STATUS_OBJECT_NAME_NOT_FOUND );
 491     return handle;
 492 }
 493
 494 /* return the size of the handle table of a given process */
 495 unsigned int get_handle_table_count( struct process *process )
 496 {
 497     if (!process->handles) return 0;
 498     return process->handles->count;
 499 }
 500
 501 /* close a handle */
 502 DECL_HANDLER(close_handle)
 503 {
 504     close_handle( current->process, req->handle );
 505 }
 506
 507 /* set a handle information */
 508 DECL_HANDLER(set_handle_info)
 509 {
 510     reply->old_flags = set_handle_flags( current->process, req->handle, req->mask, req->flags );
 511 }
 512
 513 /* duplicate a handle */
 514 DECL_HANDLER(dup_handle)
 515 {
 516     struct process *src, *dst;
 517
 518     reply->handle = 0;
 519     if ((src = get_process_from_handle( req->src_process, PROCESS_DUP_HANDLE )))
 520     {
 521         if (req->options & DUP_HANDLE_MAKE_GLOBAL)
 522         {
 523             reply->handle = duplicate_handle( src, req->src_handle, NULL,
 524                                               req->access, req->attributes, req->options );
 525         }
 526         else if ((dst = get_process_from_handle( req->dst_process, PROCESS_DUP_HANDLE )))
 527         {
 528             reply->handle = duplicate_handle( src, req->src_handle, dst,
 529                                               req->access, req->attributes, req->options );
 530             release_object( dst );
 531         }
 532         /* close the handle no matter what happened */
 533         if (req->options & DUP_HANDLE_CLOSE_SOURCE)
 534         {
 535             unsigned int err = get_error();  /* don't overwrite error from the above calls */
 536             reply->closed = close_handle( src, req->src_handle );
 537             set_error( err );
 538         }
 539         release_object( src );
 540     }
 541 }