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_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     entry->fd     = -1;
 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 obj_handle_t alloc_handle( struct process *process, void *obj, unsigned int access, int inherit )
 227 {
 228     access &= ~RESERVED_ALL;
 229     if (inherit) access |= RESERVED_INHERIT;
 230     if (!process->handles)
 231     {
 232         set_error( STATUS_NO_MEMORY );
 233         return 0;
 234     }
 235     return alloc_entry( process->handles, obj, access );
 236 }
 237
 238 /* allocate a global handle for an object, incrementing its refcount */
 239 /* return the handle, or 0 on error */
 240 static obj_handle_t alloc_global_handle( void *obj, unsigned int access )
 241 {
 242     if (!global_table)
 243     {
 244         if (!(global_table = (struct handle_table *)alloc_handle_table( NULL, 0 )))
 245             return 0;
 246     }
 247     return handle_local_to_global( alloc_entry( global_table, obj, access ));
 248 }
 249
 250 /* return a handle entry, or NULL if the handle is invalid */
 251 static struct handle_entry *get_handle( struct process *process, obj_handle_t handle )
 252 {
 253     struct handle_table *table = process->handles;
 254     struct handle_entry *entry;
 255     int index;
 256
 257     if (handle_is_global(handle))
 258     {
 259         handle = handle_global_to_local(handle);
 260         table = global_table;
 261     }
 262     if (!table) goto error;
 263     index = handle_to_index( handle );
 264     if (index < 0) goto error;
 265     if (index > table->last) goto error;
 266     entry = table->entries + index;
 267     if (!entry->ptr) goto error;
 268     return entry;
 269
 270  error:
 271     set_error( STATUS_INVALID_HANDLE );
 272     return NULL;
 273 }
 274
 275 /* attempt to shrink a table */
 276 static void shrink_handle_table( struct handle_table *table )
 277 {
 278     struct handle_entry *entry = table->entries + table->last;
 279     struct handle_entry *new_entries;
 280     int count = table->count;
 281
 282     while (table->last >= 0)
 283     {
 284         if (entry->ptr) break;
 285         table->last--;
 286         entry--;
 287     }
 288     if (table->last >= count / 4) return;  /* no need to shrink */
 289     if (count < MIN_HANDLE_ENTRIES * 2) return;  /* too small to shrink */
 290     count /= 2;
 291     if (!(new_entries = realloc( table->entries, count * sizeof(*new_entries) ))) return;
 292     table->count   = count;
 293     table->entries = new_entries;
 294 }
 295
 296 /* copy the handle table of the parent process */
 297 /* return 1 if OK, 0 on error */
 298 struct handle_table *copy_handle_table( struct process *process, struct process *parent )
 299 {
 300     struct handle_table *parent_table = parent->handles;
 301     struct handle_table *table;
 302     int i;
 303
 304     assert( parent_table );
 305     assert( parent_table->obj.ops == &handle_table_ops );
 306
 307     if (!(table = (struct handle_table *)alloc_handle_table( process, parent_table->count )))
 308         return NULL;
 309
 310     if ((table->last = parent_table->last) >= 0)
 311     {
 312         struct handle_entry *ptr = table->entries;
 313         memcpy( ptr, parent_table->entries, (table->last + 1) * sizeof(struct handle_entry) );
 314         for (i = 0; i <= table->last; i++, ptr++)
 315         {
 316             if (!ptr->ptr) continue;
 317             ptr->fd = -1;
 318             if (ptr->access & RESERVED_INHERIT) grab_object( ptr->ptr );
 319             else ptr->ptr = NULL; /* don't inherit this entry */
 320         }
 321     }
 322     /* attempt to shrink the table */
 323     shrink_handle_table( table );
 324     return table;
 325 }
 326
 327 /* close a handle and decrement the refcount of the associated object */
 328 /* return 1 if OK, 0 on error */
 329 int close_handle( struct process *process, obj_handle_t handle, int *fd )
 330 {
 331     struct handle_table *table;
 332     struct handle_entry *entry;
 333     struct object *obj;
 334
 335     if (!(entry = get_handle( process, handle ))) return 0;
 336     if (entry->access & RESERVED_CLOSE_PROTECT)
 337     {
 338         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 339         return 0;
 340     }
 341     obj = entry->ptr;
 342     if (!obj->ops->close_handle( obj, process, handle ))
 343     {
 344         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 345         return 0;
 346     }
 347     entry->ptr = NULL;
 348     if (fd) *fd = entry->fd;
 349     else if (entry->fd != -1) return 1;  /* silently ignore close attempt if we cannot close the fd */
 350     entry->fd = -1;
 351     table = handle_is_global(handle) ? global_table : process->handles;
 352     if (entry < table->entries + table->free) table->free = entry - table->entries;
 353     if (entry == table->entries + table->last) shrink_handle_table( table );
 354     release_object( obj );
 355     return 1;
 356 }
 357
 358 /* close all the global handles */
 359 void close_global_handles(void)
 360 {
 361     if (global_table)
 362     {
 363         release_object( global_table );
 364         global_table = NULL;
 365     }
 366 }
 367
 368 /* retrieve the object corresponding to one of the magic pseudo-handles */
 369 static inline struct object *get_magic_handle( obj_handle_t handle )
 370 {
 371     switch((unsigned long)handle)
 372     {
 373         case 0xfffffffe:  /* current thread pseudo-handle */
 374             return &current->obj;
 375         case 0x7fffffff:  /* current process pseudo-handle */
 376         case 0xffffffff:  /* current process pseudo-handle */
 377             return (struct object *)current->process;
 378         default:
 379             return NULL;
 380     }
 381 }
 382
 383 /* retrieve the object corresponding to a handle, incrementing its refcount */
 384 struct object *get_handle_obj( struct process *process, obj_handle_t handle,
 385                                unsigned int access, const struct object_ops *ops )
 386 {
 387     struct handle_entry *entry;
 388     struct object *obj;
 389
 390     if (!(obj = get_magic_handle( handle )))
 391     {
 392         if (!(entry = get_handle( process, handle ))) return NULL;
 393         if ((entry->access & access) != access)
 394         {
 395             set_error( STATUS_ACCESS_DENIED );
 396             return NULL;
 397         }
 398         obj = entry->ptr;
 399     }
 400     if (ops && (obj->ops != ops))
 401     {
 402         set_error( STATUS_OBJECT_TYPE_MISMATCH );  /* not the right type */
 403         return NULL;
 404     }
 405     return grab_object( obj );
 406 }
 407
 408 /* retrieve the access rights of a given handle */
 409 unsigned int get_handle_access( struct process *process, obj_handle_t handle )
 410 {
 411     struct handle_entry *entry;
 412
 413     if (get_magic_handle( handle )) return ~0U;  /* magic handles have all access rights */
 414     if (!(entry = get_handle( process, handle ))) return 0;
 415     return entry->access;
 416 }
 417
 418 /* retrieve the cached fd for a given handle */
 419 int get_handle_unix_fd( struct process *process, obj_handle_t handle, unsigned int access )
 420 {
 421     struct handle_entry *entry;
 422
 423     if (!(entry = get_handle( process, handle ))) return -1;
 424     if ((entry->access & access) != access)
 425     {
 426         set_error( STATUS_ACCESS_DENIED );
 427         return -1;
 428     }
 429     return entry->fd;
 430 }
 431
 432 /* set the cached fd for a handle if not set already, and return the current value */
 433 int set_handle_unix_fd( struct process *process, obj_handle_t handle, int fd )
 434 {
 435     struct handle_entry *entry;
 436
 437     if (handle_is_global( handle )) return -1;  /* no fd cache for global handles */
 438     if (!(entry = get_handle( process, handle ))) return -1;
 439     /* if no current fd set it, otherwise return current fd */
 440     if (entry->fd == -1) entry->fd = fd;
 441     return entry->fd;
 442 }
 443
 444 /* remove the cached fd and return it */
 445 int flush_cached_fd( struct process *process, obj_handle_t handle )
 446 {
 447     struct handle_entry *entry = get_handle( process, handle );
 448     int fd = -1;
 449
 450     if (entry)
 451     {
 452         fd = entry->fd;
 453         entry->fd = -1;
 454     }
 455     return fd;
 456 }
 457
 458 /* find the first inherited handle of the given type */
 459 /* this is needed for window stations and desktops (don't ask...) */
 460 obj_handle_t find_inherited_handle( struct process *process, const struct object_ops *ops )
 461 {
 462     struct handle_table *table = process->handles;
 463     struct handle_entry *ptr;
 464     int i;
 465
 466     if (!table) return 0;
 467
 468     for (i = 0, ptr = table->entries; i <= table->last; i++, ptr++)
 469     {
 470         if (!ptr->ptr) continue;
 471         if (ptr->ptr->ops != ops) continue;
 472         if (ptr->access & RESERVED_INHERIT) return index_to_handle(i);
 473     }
 474     return 0;
 475 }
 476
 477 /* get/set the handle reserved flags */
 478 /* return the old flags (or -1 on error) */
 479 static int set_handle_flags( struct process *process, obj_handle_t handle, int mask, int flags )
 480 {
 481     struct handle_entry *entry;
 482     unsigned int old_access;
 483
 484     if (get_magic_handle( handle ))
 485     {
 486         /* we can retrieve but not set info for magic handles */
 487         if (mask) set_error( STATUS_ACCESS_DENIED );
 488         return 0;
 489     }
 490     if (!(entry = get_handle( process, handle ))) return -1;
 491     old_access = entry->access;
 492     mask  = (mask << RESERVED_SHIFT) & RESERVED_ALL;
 493     flags = (flags << RESERVED_SHIFT) & mask;
 494     entry->access = (entry->access & ~mask) | flags;
 495     return (old_access & RESERVED_ALL) >> RESERVED_SHIFT;
 496 }
 497
 498 /* duplicate a handle */
 499 obj_handle_t duplicate_handle( struct process *src, obj_handle_t src_handle, struct process *dst,
 500                            unsigned int access, int inherit, int options )
 501 {
 502     obj_handle_t res;
 503     struct object *obj = get_handle_obj( src, src_handle, 0, NULL );
 504
 505     if (!obj) return 0;
 506     if (options & DUP_HANDLE_SAME_ACCESS)
 507     {
 508         struct handle_entry *entry = get_handle( src, src_handle );
 509         if (entry)
 510             access = entry->access;
 511         else  /* pseudo-handle, give it full access */
 512         {
 513             access = STANDARD_RIGHTS_ALL | SPECIFIC_RIGHTS_ALL;
 514             clear_error();
 515         }
 516     }
 517     access &= ~RESERVED_ALL;
 518     if (options & DUP_HANDLE_MAKE_GLOBAL)
 519         res = alloc_global_handle( obj, access );
 520     else
 521         res = alloc_handle( dst, obj, access, inherit );
 522     release_object( obj );
 523     return res;
 524 }
 525
 526 /* open a new handle to an existing object */
 527 obj_handle_t open_object( const struct namespace *namespace, const struct unicode_str *name,
 528                           const struct object_ops *ops, unsigned int access, unsigned int attr )
 529 {
 530     obj_handle_t handle = 0;
 531     struct object *obj = find_object( namespace, name, attr );
 532     if (obj)
 533     {
 534         if (ops && obj->ops != ops)
 535             set_error( STATUS_OBJECT_TYPE_MISMATCH );
 536         else
 537             handle = alloc_handle( current->process, obj, access, attr & OBJ_INHERIT );
 538         release_object( obj );
 539     }
 540     else
 541         set_error( STATUS_OBJECT_NAME_NOT_FOUND );
 542     return handle;
 543 }
 544
 545 /* return the size of the handle table of a given process */
 546 unsigned int get_handle_table_count( struct process *process )
 547 {
 548     if (!process->handles) return 0;
 549     return process->handles->count;
 550 }
 551
 552 /* close a handle */
 553 DECL_HANDLER(close_handle)
 554 {
 555     close_handle( current->process, req->handle, &reply->fd );
 556 }
 557
 558 /* set a handle information */
 559 DECL_HANDLER(set_handle_info)
 560 {
 561     reply->old_flags = set_handle_flags( current->process, req->handle, req->mask, req->flags );
 562 }
 563
 564 /* duplicate a handle */
 565 DECL_HANDLER(dup_handle)
 566 {
 567     struct process *src, *dst;
 568
 569     reply->handle = 0;
 570     reply->fd = -1;
 571     if ((src = get_process_from_handle( req->src_process, PROCESS_DUP_HANDLE )))
 572     {
 573         if (req->options & DUP_HANDLE_MAKE_GLOBAL)
 574         {
 575             reply->handle = duplicate_handle( src, req->src_handle, NULL,
 576                                               req->access, req->inherit, req->options );
 577         }
 578         else if ((dst = get_process_from_handle( req->dst_process, PROCESS_DUP_HANDLE )))
 579         {
 580             reply->handle = duplicate_handle( src, req->src_handle, dst,
 581                                               req->access, req->inherit, req->options );
 582             release_object( dst );
 583         }
 584         /* close the handle no matter what happened */
 585         if (req->options & DUP_HANDLE_CLOSE_SOURCE)
 586         {
 587             if (src == current->process) close_handle( src, req->src_handle, &reply->fd );
 588             else close_handle( src, req->src_handle, NULL );
 589         }
 590         release_object( src );
 591     }
 592 }