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 "security.h"
  40 #include "request.h"
  41
  42 struct handle_entry
  43 {
  44     struct object *ptr;       /* object */
  45     unsigned int   access;    /* access rights */
  46 };
  47
  48 struct handle_table
  49 {
  50     struct object        obj;         /* object header */
  51     struct process      *process;     /* process owning this table */
  52     int                  count;       /* number of allocated entries */
  53     int                  last;        /* last used entry */
  54     int                  free;        /* first entry that may be free */
  55     struct handle_entry *entries;     /* handle entries */
  56 };
  57
  58 static struct handle_table *global_table;
  59
  60 /* reserved handle access rights */
  61 #define RESERVED_SHIFT         26
  62 #define RESERVED_INHERIT       (HANDLE_FLAG_INHERIT << RESERVED_SHIFT)
  63 #define RESERVED_CLOSE_PROTECT (HANDLE_FLAG_PROTECT_FROM_CLOSE << RESERVED_SHIFT)
  64 #define RESERVED_ALL           (RESERVED_INHERIT | RESERVED_CLOSE_PROTECT)
  65
  66 #define MIN_HANDLE_ENTRIES  32
  67
  68
  69 /* handle to table index conversion */
  70
  71 /* handles are a multiple of 4 under NT; handle 0 is not used */
  72 inline static obj_handle_t index_to_handle( int index )
  73 {
  74     return (obj_handle_t)((unsigned long)(index + 1) << 2);
  75 }
  76 inline static int handle_to_index( obj_handle_t handle )
  77 {
  78     return ((unsigned long)handle >> 2) - 1;
  79 }
  80
  81 /* global handle conversion */
  82
  83 #define HANDLE_OBFUSCATOR 0x544a4def
  84
  85 inline static int handle_is_global( obj_handle_t handle)
  86 {
  87     return ((unsigned long)handle ^ HANDLE_OBFUSCATOR) < 0x10000;
  88 }
  89 inline static obj_handle_t handle_local_to_global( obj_handle_t handle )
  90 {
  91     if (!handle) return 0;
  92     return (obj_handle_t)((unsigned long)handle ^ HANDLE_OBFUSCATOR);
  93 }
  94 inline static obj_handle_t handle_global_to_local( obj_handle_t handle )
  95 {
  96     return (obj_handle_t)((unsigned long)handle ^ HANDLE_OBFUSCATOR);
  97 }
  98
  99
 100 static void handle_table_dump( struct object *obj, int verbose );
 101 static void handle_table_destroy( struct object *obj );
 102
 103 static const struct object_ops handle_table_ops =
 104 {
 105     sizeof(struct handle_table),     /* size */
 106     handle_table_dump,               /* dump */
 107     no_add_queue,                    /* add_queue */
 108     NULL,                            /* remove_queue */
 109     NULL,                            /* signaled */
 110     NULL,                            /* satisfied */
 111     no_signal,                       /* signal */
 112     no_get_fd,                       /* get_fd */
 113     no_map_access,                   /* map_access */
 114     no_lookup_name,                  /* lookup_name */
 115     no_close_handle,                 /* close_handle */
 116     handle_table_destroy             /* destroy */
 117 };
 118
 119 /* dump a handle table */
 120 static void handle_table_dump( struct object *obj, int verbose )
 121 {
 122     int i;
 123     struct handle_table *table = (struct handle_table *)obj;
 124     struct handle_entry *entry = table->entries;
 125
 126     assert( obj->ops == &handle_table_ops );
 127
 128     fprintf( stderr, "Handle table last=%d count=%d process=%p\n",
 129              table->last, table->count, table->process );
 130     if (!verbose) return;
 131     entry = table->entries;
 132     for (i = 0; i <= table->last; i++, entry++)
 133     {
 134         if (!entry->ptr) continue;
 135         fprintf( stderr, "    %p: %p %08x ",
 136                  index_to_handle(i), entry->ptr, entry->access );
 137         entry->ptr->ops->dump( entry->ptr, 0 );
 138     }
 139 }
 140
 141 /* destroy a handle table */
 142 static void handle_table_destroy( struct object *obj )
 143 {
 144     int i;
 145     struct handle_table *table = (struct handle_table *)obj;
 146     struct handle_entry *entry;
 147
 148     assert( obj->ops == &handle_table_ops );
 149
 150     /* first notify all objects that handles are being closed */
 151     if (table->process)
 152     {
 153         for (i = 0, entry = table->entries; i <= table->last; i++, entry++)
 154         {
 155             struct object *obj = entry->ptr;
 156             if (obj) obj->ops->close_handle( obj, table->process, index_to_handle(i) );
 157         }
 158     }
 159
 160     for (i = 0, entry = table->entries; i <= table->last; i++, entry++)
 161     {
 162         struct object *obj = entry->ptr;
 163         entry->ptr = NULL;
 164         if (obj) release_object( obj );
 165     }
 166     free( table->entries );
 167 }
 168
 169 /* allocate a new handle table */
 170 struct handle_table *alloc_handle_table( struct process *process, int count )
 171 {
 172     struct handle_table *table;
 173
 174     if (count < MIN_HANDLE_ENTRIES) count = MIN_HANDLE_ENTRIES;
 175     if (!(table = alloc_object( &handle_table_ops )))
 176         return NULL;
 177     table->process = process;
 178     table->count   = count;
 179     table->last    = -1;
 180     table->free    = 0;
 181     if ((table->entries = mem_alloc( count * sizeof(*table->entries) ))) return table;
 182     release_object( table );
 183     return NULL;
 184 }
 185
 186 /* grow a handle table */
 187 static int grow_handle_table( struct handle_table *table )
 188 {
 189     struct handle_entry *new_entries;
 190     int count = table->count;
 191
 192     if (count >= INT_MAX / 2) return 0;
 193     count *= 2;
 194     if (!(new_entries = realloc( table->entries, count * sizeof(struct handle_entry) )))
 195     {
 196         set_error( STATUS_NO_MEMORY );
 197         return 0;
 198     }
 199     table->entries = new_entries;
 200     table->count   = count;
 201     return 1;
 202 }
 203
 204 /* allocate the first free entry in the handle table */
 205 static obj_handle_t alloc_entry( struct handle_table *table, void *obj, unsigned int access )
 206 {
 207     struct handle_entry *entry = table->entries + table->free;
 208     int i;
 209
 210     for (i = table->free; i <= table->last; i++, entry++) if (!entry->ptr) goto found;
 211     if (i >= table->count)
 212     {
 213         if (!grow_handle_table( table )) return 0;
 214         entry = table->entries + i;  /* the entries may have moved */
 215     }
 216     table->last = i;
 217  found:
 218     table->free = i + 1;
 219     entry->ptr    = grab_object( obj );
 220     entry->access = access;
 221     return index_to_handle(i);
 222 }
 223
 224 /* allocate a handle for an object, incrementing its refcount */
 225 /* return the handle, or 0 on error */
 226 static obj_handle_t alloc_handle_no_access_check( struct process *process, void *ptr, unsigned int access, unsigned int attr )
 227 {
 228     struct object *obj = ptr;
 229
 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 handle for an object, checking the dacl allows the process to */
 241 /* access it and incrementing its refcount */
 242 /* return the handle, or 0 on error */
 243 obj_handle_t alloc_handle( struct process *process, void *ptr, unsigned int access, unsigned int attr )
 244 {
 245     struct object *obj = ptr;
 246     access = obj->ops->map_access( obj, access );
 247     if (access && !check_object_access( obj, &access )) return 0;
 248     return alloc_handle_no_access_check( process, ptr, access, attr );
 249 }
 250
 251 /* allocate a global handle for an object, incrementing its refcount */
 252 /* return the handle, or 0 on error */
 253 static obj_handle_t alloc_global_handle_no_access_check( void *obj, unsigned int access )
 254 {
 255     if (!global_table)
 256     {
 257         if (!(global_table = (struct handle_table *)alloc_handle_table( NULL, 0 )))
 258             return 0;
 259         make_object_static( &global_table->obj );
 260     }
 261     return handle_local_to_global( alloc_entry( global_table, obj, access ));
 262 }
 263
 264 /* allocate a global handle for an object, checking the dacl allows the */
 265 /* process to access it and incrementing its refcount and incrementing its refcount */
 266 /* return the handle, or 0 on error */
 267 static obj_handle_t alloc_global_handle( void *obj, unsigned int access )
 268 {
 269     if (access && !check_object_access( obj, &access )) return 0;
 270     return alloc_global_handle_no_access_check( obj, access );
 271 }
 272
 273 /* return a handle entry, or NULL if the handle is invalid */
 274 static struct handle_entry *get_handle( struct process *process, obj_handle_t handle )
 275 {
 276     struct handle_table *table = process->handles;
 277     struct handle_entry *entry;
 278     int index;
 279
 280     if (handle_is_global(handle))
 281     {
 282         handle = handle_global_to_local(handle);
 283         table = global_table;
 284     }
 285     if (!table) goto error;
 286     index = handle_to_index( handle );
 287     if (index < 0) goto error;
 288     if (index > table->last) goto error;
 289     entry = table->entries + index;
 290     if (!entry->ptr) goto error;
 291     return entry;
 292
 293  error:
 294     set_error( STATUS_INVALID_HANDLE );
 295     return NULL;
 296 }
 297
 298 /* attempt to shrink a table */
 299 static void shrink_handle_table( struct handle_table *table )
 300 {
 301     struct handle_entry *entry = table->entries + table->last;
 302     struct handle_entry *new_entries;
 303     int count = table->count;
 304
 305     while (table->last >= 0)
 306     {
 307         if (entry->ptr) break;
 308         table->last--;
 309         entry--;
 310     }
 311     if (table->last >= count / 4) return;  /* no need to shrink */
 312     if (count < MIN_HANDLE_ENTRIES * 2) return;  /* too small to shrink */
 313     count /= 2;
 314     if (!(new_entries = realloc( table->entries, count * sizeof(*new_entries) ))) return;
 315     table->count   = count;
 316     table->entries = new_entries;
 317 }
 318
 319 /* copy the handle table of the parent process */
 320 /* return 1 if OK, 0 on error */
 321 struct handle_table *copy_handle_table( struct process *process, struct process *parent )
 322 {
 323     struct handle_table *parent_table = parent->handles;
 324     struct handle_table *table;
 325     int i;
 326
 327     assert( parent_table );
 328     assert( parent_table->obj.ops == &handle_table_ops );
 329
 330     if (!(table = (struct handle_table *)alloc_handle_table( process, parent_table->count )))
 331         return NULL;
 332
 333     if ((table->last = parent_table->last) >= 0)
 334     {
 335         struct handle_entry *ptr = table->entries;
 336         memcpy( ptr, parent_table->entries, (table->last + 1) * sizeof(struct handle_entry) );
 337         for (i = 0; i <= table->last; i++, ptr++)
 338         {
 339             if (!ptr->ptr) continue;
 340             if (ptr->access & RESERVED_INHERIT) grab_object( ptr->ptr );
 341             else ptr->ptr = NULL; /* don't inherit this entry */
 342         }
 343     }
 344     /* attempt to shrink the table */
 345     shrink_handle_table( table );
 346     return table;
 347 }
 348
 349 /* close a handle and decrement the refcount of the associated object */
 350 /* return 1 if OK, 0 on error */
 351 int close_handle( struct process *process, obj_handle_t handle )
 352 {
 353     struct handle_table *table;
 354     struct handle_entry *entry;
 355     struct object *obj;
 356
 357     if (!(entry = get_handle( process, handle ))) return 0;
 358     if (entry->access & RESERVED_CLOSE_PROTECT)
 359     {
 360         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 361         return 0;
 362     }
 363     obj = entry->ptr;
 364     if (!obj->ops->close_handle( obj, process, handle ))
 365     {
 366         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 367         return 0;
 368     }
 369     entry->ptr = NULL;
 370     table = handle_is_global(handle) ? global_table : process->handles;
 371     if (entry < table->entries + table->free) table->free = entry - table->entries;
 372     if (entry == table->entries + table->last) shrink_handle_table( table );
 373     release_object( obj );
 374     return 1;
 375 }
 376
 377 /* retrieve the object corresponding to one of the magic pseudo-handles */
 378 static inline struct object *get_magic_handle( obj_handle_t handle )
 379 {
 380     switch((unsigned long)handle)
 381     {
 382         case 0xfffffffe:  /* current thread pseudo-handle */
 383             return &current->obj;
 384         case 0x7fffffff:  /* current process pseudo-handle */
 385         case 0xffffffff:  /* current process pseudo-handle */
 386             return (struct object *)current->process;
 387         default:
 388             return NULL;
 389     }
 390 }
 391
 392 /* retrieve the object corresponding to a handle, incrementing its refcount */
 393 struct object *get_handle_obj( struct process *process, obj_handle_t handle,
 394                                unsigned int access, const struct object_ops *ops )
 395 {
 396     struct handle_entry *entry;
 397     struct object *obj;
 398
 399     if (!(obj = get_magic_handle( handle )))
 400     {
 401         if (!(entry = get_handle( process, handle ))) return NULL;
 402         if ((entry->access & access) != access)
 403         {
 404             set_error( STATUS_ACCESS_DENIED );
 405             return NULL;
 406         }
 407         obj = entry->ptr;
 408     }
 409     if (ops && (obj->ops != ops))
 410     {
 411         set_error( STATUS_OBJECT_TYPE_MISMATCH );  /* not the right type */
 412         return NULL;
 413     }
 414     return grab_object( obj );
 415 }
 416
 417 /* retrieve the access rights of a given handle */
 418 unsigned int get_handle_access( struct process *process, obj_handle_t handle )
 419 {
 420     struct handle_entry *entry;
 421
 422     if (get_magic_handle( handle )) return ~RESERVED_ALL;  /* magic handles have all access rights */
 423     if (!(entry = get_handle( process, handle ))) return 0;
 424     return entry->access & ~RESERVED_ALL;
 425 }
 426
 427 /* find the first inherited handle of the given type */
 428 /* this is needed for window stations and desktops (don't ask...) */
 429 obj_handle_t find_inherited_handle( struct process *process, const struct object_ops *ops )
 430 {
 431     struct handle_table *table = process->handles;
 432     struct handle_entry *ptr;
 433     int i;
 434
 435     if (!table) return 0;
 436
 437     for (i = 0, ptr = table->entries; i <= table->last; i++, ptr++)
 438     {
 439         if (!ptr->ptr) continue;
 440         if (ptr->ptr->ops != ops) continue;
 441         if (ptr->access & RESERVED_INHERIT) return index_to_handle(i);
 442     }
 443     return 0;
 444 }
 445
 446 /* get/set the handle reserved flags */
 447 /* return the old flags (or -1 on error) */
 448 static int set_handle_flags( struct process *process, obj_handle_t handle, int mask, int flags )
 449 {
 450     struct handle_entry *entry;
 451     unsigned int old_access;
 452
 453     if (get_magic_handle( handle ))
 454     {
 455         /* we can retrieve but not set info for magic handles */
 456         if (mask) set_error( STATUS_ACCESS_DENIED );
 457         return 0;
 458     }
 459     if (!(entry = get_handle( process, handle ))) return -1;
 460     old_access = entry->access;
 461     mask  = (mask << RESERVED_SHIFT) & RESERVED_ALL;
 462     flags = (flags << RESERVED_SHIFT) & mask;
 463     entry->access = (entry->access & ~mask) | flags;
 464     return (old_access & RESERVED_ALL) >> RESERVED_SHIFT;
 465 }
 466
 467 /* duplicate a handle */
 468 obj_handle_t duplicate_handle( struct process *src, obj_handle_t src_handle, struct process *dst,
 469                                unsigned int access, unsigned int attr, unsigned int options )
 470 {
 471     obj_handle_t res;
 472     struct handle_entry *entry;
 473     unsigned int src_access;
 474     struct object *obj = get_handle_obj( src, src_handle, 0, NULL );
 475
 476     if (!obj) return 0;
 477     if ((entry = get_handle( src, src_handle )))
 478         src_access = entry->access;
 479     else  /* pseudo-handle, give it full access */
 480     {
 481         src_access = obj->ops->map_access( obj, GENERIC_ALL );
 482         clear_error();
 483     }
 484     src_access &= ~RESERVED_ALL;
 485
 486     if (options & DUP_HANDLE_SAME_ACCESS)
 487         access = src_access;
 488     else
 489         access = obj->ops->map_access( obj, access ) & ~RESERVED_ALL;
 490
 491     /* asking for the more access rights than src_access? */
 492     if (access & ~src_access)
 493     {
 494         if (options & DUP_HANDLE_MAKE_GLOBAL)
 495             res = alloc_global_handle( obj, access );
 496         else
 497             res = alloc_handle( dst, obj, access, attr );
 498     }
 499     else
 500     {
 501         if (options & DUP_HANDLE_MAKE_GLOBAL)
 502             res = alloc_global_handle_no_access_check( obj, access );
 503         else
 504             res = alloc_handle_no_access_check( dst, obj, access, attr );
 505     }
 506
 507     release_object( obj );
 508     return res;
 509 }
 510
 511 /* open a new handle to an existing object */
 512 obj_handle_t open_object( const struct namespace *namespace, const struct unicode_str *name,
 513                           const struct object_ops *ops, unsigned int access, unsigned int attr )
 514 {
 515     obj_handle_t handle = 0;
 516     struct object *obj = find_object( namespace, name, attr );
 517     if (obj)
 518     {
 519         if (ops && obj->ops != ops)
 520             set_error( STATUS_OBJECT_TYPE_MISMATCH );
 521         else
 522             handle = alloc_handle( current->process, obj, access, attr );
 523         release_object( obj );
 524     }
 525     else
 526         set_error( STATUS_OBJECT_NAME_NOT_FOUND );
 527     return handle;
 528 }
 529
 530 /* return the size of the handle table of a given process */
 531 unsigned int get_handle_table_count( struct process *process )
 532 {
 533     if (!process->handles) return 0;
 534     return process->handles->count;
 535 }
 536
 537 /* close a handle */
 538 DECL_HANDLER(close_handle)
 539 {
 540     close_handle( current->process, req->handle );
 541 }
 542
 543 /* set a handle information */
 544 DECL_HANDLER(set_handle_info)
 545 {
 546     reply->old_flags = set_handle_flags( current->process, req->handle, req->mask, req->flags );
 547 }
 548
 549 /* duplicate a handle */
 550 DECL_HANDLER(dup_handle)
 551 {
 552     struct process *src, *dst;
 553
 554     reply->handle = 0;
 555     if ((src = get_process_from_handle( req->src_process, PROCESS_DUP_HANDLE )))
 556     {
 557         if (req->options & DUP_HANDLE_MAKE_GLOBAL)
 558         {
 559             reply->handle = duplicate_handle( src, req->src_handle, NULL,
 560                                               req->access, req->attributes, req->options );
 561         }
 562         else if ((dst = get_process_from_handle( req->dst_process, PROCESS_DUP_HANDLE )))
 563         {
 564             reply->handle = duplicate_handle( src, req->src_handle, dst,
 565                                               req->access, req->attributes, req->options );
 566             release_object( dst );
 567         }
 568         /* close the handle no matter what happened */
 569         if (req->options & DUP_HANDLE_CLOSE_SOURCE)
 570         {
 571             unsigned int err = get_error();  /* don't overwrite error from the above calls */
 572             reply->closed = close_handle( src, req->src_handle );
 573             set_error( err );
 574         }
 575         reply->self = (src == current->process);
 576         release_object( src );
 577     }
 578 }
 579
 580 DECL_HANDLER(get_object_info)
 581 {
 582     struct object *obj;
 583
 584     if (!(obj = get_handle_obj( current->process, req->handle, 0, NULL ))) return;
 585
 586     reply->access = get_handle_access( current->process, req->handle );
 587     reply->ref_count = obj->refcount;
 588     release_object( obj );
 589 }