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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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     int            fd;        /* file descriptor (in client process) */
  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)((index + 1) << 2);
  75 }
  76 inline static int handle_to_index( obj_handle_t handle )
  77 {
  78     return ((unsigned int)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     entry->fd     = -1;
 222     return index_to_handle(i);
 223 }
 224
 225 /* allocate a handle for an object, incrementing its refcount */
 226 /* return the handle, or 0 on error */
 227 obj_handle_t alloc_handle( struct process *process, void *ptr, unsigned int access, unsigned int attr )
 228 {
 229     struct object *obj = ptr;
 230
 231     access = obj->ops->map_access( obj, access );
 232     access &= ~RESERVED_ALL;
 233     if (attr & OBJ_INHERIT) access |= RESERVED_INHERIT;
 234     if (!process->handles)
 235     {
 236         set_error( STATUS_NO_MEMORY );
 237         return 0;
 238     }
 239     return alloc_entry( process->handles, obj, access );
 240 }
 241
 242 /* allocate a global handle for an object, incrementing its refcount */
 243 /* return the handle, or 0 on error */
 244 static obj_handle_t alloc_global_handle( void *obj, unsigned int access )
 245 {
 246     if (!global_table)
 247     {
 248         if (!(global_table = (struct handle_table *)alloc_handle_table( NULL, 0 )))
 249             return 0;
 250         make_object_static( &global_table->obj );
 251     }
 252     return handle_local_to_global( alloc_entry( global_table, obj, access ));
 253 }
 254
 255 /* return a handle entry, or NULL if the handle is invalid */
 256 static struct handle_entry *get_handle( struct process *process, obj_handle_t handle )
 257 {
 258     struct handle_table *table = process->handles;
 259     struct handle_entry *entry;
 260     int index;
 261
 262     if (handle_is_global(handle))
 263     {
 264         handle = handle_global_to_local(handle);
 265         table = global_table;
 266     }
 267     if (!table) goto error;
 268     index = handle_to_index( handle );
 269     if (index < 0) goto error;
 270     if (index > table->last) goto error;
 271     entry = table->entries + index;
 272     if (!entry->ptr) goto error;
 273     return entry;
 274
 275  error:
 276     set_error( STATUS_INVALID_HANDLE );
 277     return NULL;
 278 }
 279
 280 /* attempt to shrink a table */
 281 static void shrink_handle_table( struct handle_table *table )
 282 {
 283     struct handle_entry *entry = table->entries + table->last;
 284     struct handle_entry *new_entries;
 285     int count = table->count;
 286
 287     while (table->last >= 0)
 288     {
 289         if (entry->ptr) break;
 290         table->last--;
 291         entry--;
 292     }
 293     if (table->last >= count / 4) return;  /* no need to shrink */
 294     if (count < MIN_HANDLE_ENTRIES * 2) return;  /* too small to shrink */
 295     count /= 2;
 296     if (!(new_entries = realloc( table->entries, count * sizeof(*new_entries) ))) return;
 297     table->count   = count;
 298     table->entries = new_entries;
 299 }
 300
 301 /* copy the handle table of the parent process */
 302 /* return 1 if OK, 0 on error */
 303 struct handle_table *copy_handle_table( struct process *process, struct process *parent )
 304 {
 305     struct handle_table *parent_table = parent->handles;
 306     struct handle_table *table;
 307     int i;
 308
 309     assert( parent_table );
 310     assert( parent_table->obj.ops == &handle_table_ops );
 311
 312     if (!(table = (struct handle_table *)alloc_handle_table( process, parent_table->count )))
 313         return NULL;
 314
 315     if ((table->last = parent_table->last) >= 0)
 316     {
 317         struct handle_entry *ptr = table->entries;
 318         memcpy( ptr, parent_table->entries, (table->last + 1) * sizeof(struct handle_entry) );
 319         for (i = 0; i <= table->last; i++, ptr++)
 320         {
 321             if (!ptr->ptr) continue;
 322             ptr->fd = -1;
 323             if (ptr->access & RESERVED_INHERIT) grab_object( ptr->ptr );
 324             else ptr->ptr = NULL; /* don't inherit this entry */
 325         }
 326     }
 327     /* attempt to shrink the table */
 328     shrink_handle_table( table );
 329     return table;
 330 }
 331
 332 /* close a handle and decrement the refcount of the associated object */
 333 /* return 1 if OK, 0 on error */
 334 int close_handle( struct process *process, obj_handle_t handle, int *fd )
 335 {
 336     struct handle_table *table;
 337     struct handle_entry *entry;
 338     struct object *obj;
 339
 340     if (!(entry = get_handle( process, handle ))) return 0;
 341     if (entry->access & RESERVED_CLOSE_PROTECT)
 342     {
 343         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 344         return 0;
 345     }
 346     obj = entry->ptr;
 347     if (!obj->ops->close_handle( obj, process, handle ))
 348     {
 349         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 350         return 0;
 351     }
 352     entry->ptr = NULL;
 353     if (fd) *fd = entry->fd;
 354     else if (entry->fd != -1) return 1;  /* silently ignore close attempt if we cannot close the fd */
 355     entry->fd = -1;
 356     table = handle_is_global(handle) ? global_table : process->handles;
 357     if (entry < table->entries + table->free) table->free = entry - table->entries;
 358     if (entry == table->entries + table->last) shrink_handle_table( table );
 359     release_object( obj );
 360     return 1;
 361 }
 362
 363 /* retrieve the object corresponding to one of the magic pseudo-handles */
 364 static inline struct object *get_magic_handle( obj_handle_t handle )
 365 {
 366     switch((unsigned long)handle)
 367     {
 368         case 0xfffffffe:  /* current thread pseudo-handle */
 369             return &current->obj;
 370         case 0x7fffffff:  /* current process pseudo-handle */
 371         case 0xffffffff:  /* current process pseudo-handle */
 372             return (struct object *)current->process;
 373         default:
 374             return NULL;
 375     }
 376 }
 377
 378 /* retrieve the object corresponding to a handle, incrementing its refcount */
 379 struct object *get_handle_obj( struct process *process, obj_handle_t handle,
 380                                unsigned int access, const struct object_ops *ops )
 381 {
 382     struct handle_entry *entry;
 383     struct object *obj;
 384
 385     if (!(obj = get_magic_handle( handle )))
 386     {
 387         if (!(entry = get_handle( process, handle ))) return NULL;
 388         if ((entry->access & access) != access)
 389         {
 390             set_error( STATUS_ACCESS_DENIED );
 391             return NULL;
 392         }
 393         obj = entry->ptr;
 394     }
 395     if (ops && (obj->ops != ops))
 396     {
 397         set_error( STATUS_OBJECT_TYPE_MISMATCH );  /* not the right type */
 398         return NULL;
 399     }
 400     return grab_object( obj );
 401 }
 402
 403 /* retrieve the access rights of a given handle */
 404 unsigned int get_handle_access( struct process *process, obj_handle_t handle )
 405 {
 406     struct handle_entry *entry;
 407
 408     if (get_magic_handle( handle )) return ~0U;  /* magic handles have all access rights */
 409     if (!(entry = get_handle( process, handle ))) return 0;
 410     return entry->access;
 411 }
 412
 413 /* retrieve the cached fd for a given handle */
 414 int get_handle_unix_fd( struct process *process, obj_handle_t handle, unsigned int access )
 415 {
 416     struct handle_entry *entry;
 417
 418     if (!(entry = get_handle( process, handle ))) return -1;
 419     if ((entry->access & access) != access)
 420     {
 421         set_error( STATUS_ACCESS_DENIED );
 422         return -1;
 423     }
 424     return entry->fd;
 425 }
 426
 427 /* set the cached fd for a handle if not set already, and return the current value */
 428 int set_handle_unix_fd( struct process *process, obj_handle_t handle, int fd )
 429 {
 430     struct handle_entry *entry;
 431
 432     if (handle_is_global( handle )) return -1;  /* no fd cache for global handles */
 433     if (!(entry = get_handle( process, handle ))) return -1;
 434     /* if no current fd set it, otherwise return current fd */
 435     if (entry->fd == -1) entry->fd = fd;
 436     return entry->fd;
 437 }
 438
 439 /* remove the cached fd and return it */
 440 int flush_cached_fd( struct process *process, obj_handle_t handle )
 441 {
 442     struct handle_entry *entry = get_handle( process, handle );
 443     int fd = -1;
 444
 445     if (entry)
 446     {
 447         fd = entry->fd;
 448         entry->fd = -1;
 449     }
 450     return fd;
 451 }
 452
 453 /* find the first inherited handle of the given type */
 454 /* this is needed for window stations and desktops (don't ask...) */
 455 obj_handle_t find_inherited_handle( struct process *process, const struct object_ops *ops )
 456 {
 457     struct handle_table *table = process->handles;
 458     struct handle_entry *ptr;
 459     int i;
 460
 461     if (!table) return 0;
 462
 463     for (i = 0, ptr = table->entries; i <= table->last; i++, ptr++)
 464     {
 465         if (!ptr->ptr) continue;
 466         if (ptr->ptr->ops != ops) continue;
 467         if (ptr->access & RESERVED_INHERIT) return index_to_handle(i);
 468     }
 469     return 0;
 470 }
 471
 472 /* get/set the handle reserved flags */
 473 /* return the old flags (or -1 on error) */
 474 static int set_handle_flags( struct process *process, obj_handle_t handle, int mask, int flags )
 475 {
 476     struct handle_entry *entry;
 477     unsigned int old_access;
 478
 479     if (get_magic_handle( handle ))
 480     {
 481         /* we can retrieve but not set info for magic handles */
 482         if (mask) set_error( STATUS_ACCESS_DENIED );
 483         return 0;
 484     }
 485     if (!(entry = get_handle( process, handle ))) return -1;
 486     old_access = entry->access;
 487     mask  = (mask << RESERVED_SHIFT) & RESERVED_ALL;
 488     flags = (flags << RESERVED_SHIFT) & mask;
 489     entry->access = (entry->access & ~mask) | flags;
 490     return (old_access & RESERVED_ALL) >> RESERVED_SHIFT;
 491 }
 492
 493 /* duplicate a handle */
 494 obj_handle_t duplicate_handle( struct process *src, obj_handle_t src_handle, struct process *dst,
 495                                unsigned int access, unsigned int attr, unsigned int options )
 496 {
 497     obj_handle_t res;
 498     struct object *obj = get_handle_obj( src, src_handle, 0, NULL );
 499
 500     if (!obj) return 0;
 501     if (options & DUP_HANDLE_SAME_ACCESS)
 502     {
 503         struct handle_entry *entry = get_handle( src, src_handle );
 504         if (entry)
 505             access = entry->access;
 506         else  /* pseudo-handle, give it full access */
 507         {
 508             access = STANDARD_RIGHTS_ALL | SPECIFIC_RIGHTS_ALL;
 509             clear_error();
 510         }
 511     }
 512     access &= ~RESERVED_ALL;
 513     if (options & DUP_HANDLE_MAKE_GLOBAL)
 514         res = alloc_global_handle( obj, access );
 515     else
 516         res = alloc_handle( dst, obj, access, attr );
 517     release_object( obj );
 518     return res;
 519 }
 520
 521 /* open a new handle to an existing object */
 522 obj_handle_t open_object( const struct namespace *namespace, const struct unicode_str *name,
 523                           const struct object_ops *ops, unsigned int access, unsigned int attr )
 524 {
 525     obj_handle_t handle = 0;
 526     struct object *obj = find_object( namespace, name, attr );
 527     if (obj)
 528     {
 529         if (ops && obj->ops != ops)
 530             set_error( STATUS_OBJECT_TYPE_MISMATCH );
 531         else
 532             handle = alloc_handle( current->process, obj, access, attr );
 533         release_object( obj );
 534     }
 535     else
 536         set_error( STATUS_OBJECT_NAME_NOT_FOUND );
 537     return handle;
 538 }
 539
 540 /* return the size of the handle table of a given process */
 541 unsigned int get_handle_table_count( struct process *process )
 542 {
 543     if (!process->handles) return 0;
 544     return process->handles->count;
 545 }
 546
 547 /* close a handle */
 548 DECL_HANDLER(close_handle)
 549 {
 550     close_handle( current->process, req->handle, &reply->fd );
 551 }
 552
 553 /* set a handle information */
 554 DECL_HANDLER(set_handle_info)
 555 {
 556     reply->old_flags = set_handle_flags( current->process, req->handle, req->mask, req->flags );
 557 }
 558
 559 /* duplicate a handle */
 560 DECL_HANDLER(dup_handle)
 561 {
 562     struct process *src, *dst;
 563
 564     reply->handle = 0;
 565     reply->fd = -1;
 566     if ((src = get_process_from_handle( req->src_process, PROCESS_DUP_HANDLE )))
 567     {
 568         if (req->options & DUP_HANDLE_MAKE_GLOBAL)
 569         {
 570             reply->handle = duplicate_handle( src, req->src_handle, NULL,
 571                                               req->access, req->attributes, req->options );
 572         }
 573         else if ((dst = get_process_from_handle( req->dst_process, PROCESS_DUP_HANDLE )))
 574         {
 575             reply->handle = duplicate_handle( src, req->src_handle, dst,
 576                                               req->access, req->attributes, req->options );
 577             release_object( dst );
 578         }
 579         /* close the handle no matter what happened */
 580         if (req->options & DUP_HANDLE_CLOSE_SOURCE)
 581         {
 582             if (src == current->process) close_handle( src, req->src_handle, &reply->fd );
 583             else close_handle( src, req->src_handle, NULL );
 584         }
 585         release_object( src );
 586     }
 587 }