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 static inline obj_handle_t index_to_handle( int index )
  73 {
  74     return (obj_handle_t)((unsigned long)(index + 1) << 2);
  75 }
  76 static inline 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 static inline int handle_is_global( obj_handle_t handle)
  86 {
  87     return ((unsigned long)handle ^ HANDLE_OBFUSCATOR) < 0x10000;
  88 }
  89 static inline 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 static inline 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_open_file,                    /* open_file */
 116     no_close_handle,                 /* close_handle */
 117     handle_table_destroy             /* destroy */
 118 };
 119
 120 /* dump a handle table */
 121 static void handle_table_dump( struct object *obj, int verbose )
 122 {
 123     int i;
 124     struct handle_table *table = (struct handle_table *)obj;
 125     struct handle_entry *entry = table->entries;
 126
 127     assert( obj->ops == &handle_table_ops );
 128
 129     fprintf( stderr, "Handle table last=%d count=%d process=%p\n",
 130              table->last, table->count, table->process );
 131     if (!verbose) return;
 132     entry = table->entries;
 133     for (i = 0; i <= table->last; i++, entry++)
 134     {
 135         if (!entry->ptr) continue;
 136         fprintf( stderr, "    %p: %p %08x ",
 137                  index_to_handle(i), entry->ptr, entry->access );
 138         entry->ptr->ops->dump( entry->ptr, 0 );
 139     }
 140 }
 141
 142 /* destroy a handle table */
 143 static void handle_table_destroy( struct object *obj )
 144 {
 145     int i;
 146     struct handle_table *table = (struct handle_table *)obj;
 147     struct handle_entry *entry;
 148
 149     assert( obj->ops == &handle_table_ops );
 150
 151     /* first notify all objects that handles are being closed */
 152     if (table->process)
 153     {
 154         for (i = 0, entry = table->entries; i <= table->last; i++, entry++)
 155         {
 156             struct object *obj = entry->ptr;
 157             if (obj) obj->ops->close_handle( obj, table->process, index_to_handle(i) );
 158         }
 159     }
 160
 161     for (i = 0, entry = table->entries; i <= table->last; i++, entry++)
 162     {
 163         struct object *obj = entry->ptr;
 164         entry->ptr = NULL;
 165         if (obj) release_object( obj );
 166     }
 167     free( table->entries );
 168 }
 169
 170 /* allocate a new handle table */
 171 struct handle_table *alloc_handle_table( struct process *process, int count )
 172 {
 173     struct handle_table *table;
 174
 175     if (count < MIN_HANDLE_ENTRIES) count = MIN_HANDLE_ENTRIES;
 176     if (!(table = alloc_object( &handle_table_ops )))
 177         return NULL;
 178     table->process = process;
 179     table->count   = count;
 180     table->last    = -1;
 181     table->free    = 0;
 182     if ((table->entries = mem_alloc( count * sizeof(*table->entries) ))) return table;
 183     release_object( table );
 184     return NULL;
 185 }
 186
 187 /* grow a handle table */
 188 static int grow_handle_table( struct handle_table *table )
 189 {
 190     struct handle_entry *new_entries;
 191     int count = table->count;
 192
 193     if (count >= INT_MAX / 2) return 0;
 194     count *= 2;
 195     if (!(new_entries = realloc( table->entries, count * sizeof(struct handle_entry) )))
 196     {
 197         set_error( STATUS_NO_MEMORY );
 198         return 0;
 199     }
 200     table->entries = new_entries;
 201     table->count   = count;
 202     return 1;
 203 }
 204
 205 /* allocate the first free entry in the handle table */
 206 static obj_handle_t alloc_entry( struct handle_table *table, void *obj, unsigned int access )
 207 {
 208     struct handle_entry *entry = table->entries + table->free;
 209     int i;
 210
 211     for (i = table->free; i <= table->last; i++, entry++) if (!entry->ptr) goto found;
 212     if (i >= table->count)
 213     {
 214         if (!grow_handle_table( table )) return 0;
 215         entry = table->entries + i;  /* the entries may have moved */
 216     }
 217     table->last = i;
 218  found:
 219     table->free = i + 1;
 220     entry->ptr    = grab_object( obj );
 221     entry->access = access;
 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 static obj_handle_t alloc_handle_no_access_check( struct process *process, void *ptr, unsigned int access, unsigned int attr )
 228 {
 229     struct object *obj = ptr;
 230
 231     access &= ~RESERVED_ALL;
 232     if (attr & OBJ_INHERIT) access |= RESERVED_INHERIT;
 233     if (!process->handles)
 234     {
 235         set_error( STATUS_NO_MEMORY );
 236         return 0;
 237     }
 238     return alloc_entry( process->handles, obj, access );
 239 }
 240
 241 /* allocate a handle for an object, checking the dacl allows the process to */
 242 /* access it and incrementing its refcount */
 243 /* return the handle, or 0 on error */
 244 obj_handle_t alloc_handle( struct process *process, void *ptr, unsigned int access, unsigned int attr )
 245 {
 246     struct object *obj = ptr;
 247     access = obj->ops->map_access( obj, access );
 248     if (access && !check_object_access( obj, &access )) return 0;
 249     return alloc_handle_no_access_check( process, ptr, access, attr );
 250 }
 251
 252 /* allocate a global handle for an object, incrementing its refcount */
 253 /* return the handle, or 0 on error */
 254 static obj_handle_t alloc_global_handle_no_access_check( void *obj, unsigned int access )
 255 {
 256     if (!global_table)
 257     {
 258         if (!(global_table = (struct handle_table *)alloc_handle_table( NULL, 0 )))
 259             return 0;
 260         make_object_static( &global_table->obj );
 261     }
 262     return handle_local_to_global( alloc_entry( global_table, obj, access ));
 263 }
 264
 265 /* allocate a global handle for an object, checking the dacl allows the */
 266 /* process to access it and incrementing its refcount and incrementing its refcount */
 267 /* return the handle, or 0 on error */
 268 static obj_handle_t alloc_global_handle( void *obj, unsigned int access )
 269 {
 270     if (access && !check_object_access( obj, &access )) return 0;
 271     return alloc_global_handle_no_access_check( obj, access );
 272 }
 273
 274 /* return a handle entry, or NULL if the handle is invalid */
 275 static struct handle_entry *get_handle( struct process *process, obj_handle_t handle )
 276 {
 277     struct handle_table *table = process->handles;
 278     struct handle_entry *entry;
 279     int index;
 280
 281     if (handle_is_global(handle))
 282     {
 283         handle = handle_global_to_local(handle);
 284         table = global_table;
 285     }
 286     if (!table) goto error;
 287     index = handle_to_index( handle );
 288     if (index < 0) goto error;
 289     if (index > table->last) goto error;
 290     entry = table->entries + index;
 291     if (!entry->ptr) goto error;
 292     return entry;
 293
 294  error:
 295     set_error( STATUS_INVALID_HANDLE );
 296     return NULL;
 297 }
 298
 299 /* attempt to shrink a table */
 300 static void shrink_handle_table( struct handle_table *table )
 301 {
 302     struct handle_entry *entry = table->entries + table->last;
 303     struct handle_entry *new_entries;
 304     int count = table->count;
 305
 306     while (table->last >= 0)
 307     {
 308         if (entry->ptr) break;
 309         table->last--;
 310         entry--;
 311     }
 312     if (table->last >= count / 4) return;  /* no need to shrink */
 313     if (count < MIN_HANDLE_ENTRIES * 2) return;  /* too small to shrink */
 314     count /= 2;
 315     if (!(new_entries = realloc( table->entries, count * sizeof(*new_entries) ))) return;
 316     table->count   = count;
 317     table->entries = new_entries;
 318 }
 319
 320 /* copy the handle table of the parent process */
 321 /* return 1 if OK, 0 on error */
 322 struct handle_table *copy_handle_table( struct process *process, struct process *parent )
 323 {
 324     struct handle_table *parent_table = parent->handles;
 325     struct handle_table *table;
 326     int i;
 327
 328     assert( parent_table );
 329     assert( parent_table->obj.ops == &handle_table_ops );
 330
 331     if (!(table = (struct handle_table *)alloc_handle_table( process, parent_table->count )))
 332         return NULL;
 333
 334     if ((table->last = parent_table->last) >= 0)
 335     {
 336         struct handle_entry *ptr = table->entries;
 337         memcpy( ptr, parent_table->entries, (table->last + 1) * sizeof(struct handle_entry) );
 338         for (i = 0; i <= table->last; i++, ptr++)
 339         {
 340             if (!ptr->ptr) continue;
 341             if (ptr->access & RESERVED_INHERIT) grab_object( ptr->ptr );
 342             else ptr->ptr = NULL; /* don't inherit this entry */
 343         }
 344     }
 345     /* attempt to shrink the table */
 346     shrink_handle_table( table );
 347     return table;
 348 }
 349
 350 /* close a handle and decrement the refcount of the associated object */
 351 /* return 1 if OK, 0 on error */
 352 int close_handle( struct process *process, obj_handle_t handle )
 353 {
 354     struct handle_table *table;
 355     struct handle_entry *entry;
 356     struct object *obj;
 357
 358     if (!(entry = get_handle( process, handle ))) return 0;
 359     if (entry->access & RESERVED_CLOSE_PROTECT)
 360     {
 361         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 362         return 0;
 363     }
 364     obj = entry->ptr;
 365     if (!obj->ops->close_handle( obj, process, handle ))
 366     {
 367         set_error( STATUS_HANDLE_NOT_CLOSABLE );
 368         return 0;
 369     }
 370     entry->ptr = NULL;
 371     table = handle_is_global(handle) ? global_table : process->handles;
 372     if (entry < table->entries + table->free) table->free = entry - table->entries;
 373     if (entry == table->entries + table->last) shrink_handle_table( table );
 374     release_object( obj );
 375     return 1;
 376 }
 377
 378 /* retrieve the object corresponding to one of the magic pseudo-handles */
 379 static inline struct object *get_magic_handle( obj_handle_t handle )
 380 {
 381     switch((unsigned long)handle)
 382     {
 383         case 0xfffffffe:  /* current thread pseudo-handle */
 384             return &current->obj;
 385         case 0x7fffffff:  /* current process pseudo-handle */
 386         case 0xffffffff:  /* current process pseudo-handle */
 387             return (struct object *)current->process;
 388         default:
 389             return NULL;
 390     }
 391 }
 392
 393 /* retrieve the object corresponding to a handle, incrementing its refcount */
 394 struct object *get_handle_obj( struct process *process, obj_handle_t handle,
 395                                unsigned int access, const struct object_ops *ops )
 396 {
 397     struct handle_entry *entry;
 398     struct object *obj;
 399
 400     if (!(obj = get_magic_handle( handle )))
 401     {
 402         if (!(entry = get_handle( process, handle ))) return NULL;
 403         if ((entry->access & access) != access)
 404         {
 405             set_error( STATUS_ACCESS_DENIED );
 406             return NULL;
 407         }
 408         obj = entry->ptr;
 409     }
 410     if (ops && (obj->ops != ops))
 411     {
 412         set_error( STATUS_OBJECT_TYPE_MISMATCH );  /* not the right type */
 413         return NULL;
 414     }
 415     return grab_object( obj );
 416 }
 417
 418 /* retrieve the access rights of a given handle */
 419 unsigned int get_handle_access( struct process *process, obj_handle_t handle )
 420 {
 421     struct handle_entry *entry;
 422
 423     if (get_magic_handle( handle )) return ~RESERVED_ALL;  /* magic handles have all access rights */
 424     if (!(entry = get_handle( process, handle ))) return 0;
 425     return entry->access & ~RESERVED_ALL;
 426 }
 427
 428 /* find the first inherited handle of the given type */
 429 /* this is needed for window stations and desktops (don't ask...) */
 430 obj_handle_t find_inherited_handle( struct process *process, const struct object_ops *ops )
 431 {
 432     struct handle_table *table = process->handles;
 433     struct handle_entry *ptr;
 434     int i;
 435
 436     if (!table) return 0;
 437
 438     for (i = 0, ptr = table->entries; i <= table->last; i++, ptr++)
 439     {
 440         if (!ptr->ptr) continue;
 441         if (ptr->ptr->ops != ops) continue;
 442         if (ptr->access & RESERVED_INHERIT) return index_to_handle(i);
 443     }
 444     return 0;
 445 }
 446
 447 /* get/set the handle reserved flags */
 448 /* return the old flags (or -1 on error) */
 449 static int set_handle_flags( struct process *process, obj_handle_t handle, int mask, int flags )
 450 {
 451     struct handle_entry *entry;
 452     unsigned int old_access;
 453
 454     if (get_magic_handle( handle ))
 455     {
 456         /* we can retrieve but not set info for magic handles */
 457         if (mask) set_error( STATUS_ACCESS_DENIED );
 458         return 0;
 459     }
 460     if (!(entry = get_handle( process, handle ))) return -1;
 461     old_access = entry->access;
 462     mask  = (mask << RESERVED_SHIFT) & RESERVED_ALL;
 463     flags = (flags << RESERVED_SHIFT) & mask;
 464     entry->access = (entry->access & ~mask) | flags;
 465     return (old_access & RESERVED_ALL) >> RESERVED_SHIFT;
 466 }
 467
 468 /* duplicate a handle */
 469 obj_handle_t duplicate_handle( struct process *src, obj_handle_t src_handle, struct process *dst,
 470                                unsigned int access, unsigned int attr, unsigned int options )
 471 {
 472     obj_handle_t res;
 473     struct handle_entry *entry;
 474     unsigned int src_access;
 475     struct object *obj = get_handle_obj( src, src_handle, 0, NULL );
 476
 477     if (!obj) return 0;
 478     if ((entry = get_handle( src, src_handle )))
 479         src_access = entry->access;
 480     else  /* pseudo-handle, give it full access */
 481     {
 482         src_access = obj->ops->map_access( obj, GENERIC_ALL );
 483         clear_error();
 484     }
 485     src_access &= ~RESERVED_ALL;
 486
 487     if (options & DUP_HANDLE_SAME_ACCESS)
 488         access = src_access;
 489     else
 490         access = obj->ops->map_access( obj, access ) & ~RESERVED_ALL;
 491
 492     /* asking for the more access rights than src_access? */
 493     if (access & ~src_access)
 494     {
 495         if (options & DUP_HANDLE_MAKE_GLOBAL)
 496             res = alloc_global_handle( obj, access );
 497         else
 498             res = alloc_handle( dst, obj, access, attr );
 499     }
 500     else
 501     {
 502         if (options & DUP_HANDLE_MAKE_GLOBAL)
 503             res = alloc_global_handle_no_access_check( obj, access );
 504         else
 505             res = alloc_handle_no_access_check( dst, obj, access, attr );
 506     }
 507
 508     release_object( obj );
 509     return res;
 510 }
 511
 512 /* open a new handle to an existing object */
 513 obj_handle_t open_object( const struct namespace *namespace, const struct unicode_str *name,
 514                           const struct object_ops *ops, unsigned int access, unsigned int attr )
 515 {
 516     obj_handle_t handle = 0;
 517     struct object *obj = find_object( namespace, name, attr );
 518     if (obj)
 519     {
 520         if (ops && obj->ops != ops)
 521             set_error( STATUS_OBJECT_TYPE_MISMATCH );
 522         else
 523             handle = alloc_handle( current->process, obj, access, attr );
 524         release_object( obj );
 525     }
 526     else
 527         set_error( STATUS_OBJECT_NAME_NOT_FOUND );
 528     return handle;
 529 }
 530
 531 /* return the size of the handle table of a given process */
 532 unsigned int get_handle_table_count( struct process *process )
 533 {
 534     if (!process->handles) return 0;
 535     return process->handles->count;
 536 }
 537
 538 /* close a handle */
 539 DECL_HANDLER(close_handle)
 540 {
 541     close_handle( current->process, req->handle );
 542 }
 543
 544 /* set a handle information */
 545 DECL_HANDLER(set_handle_info)
 546 {
 547     reply->old_flags = set_handle_flags( current->process, req->handle, req->mask, req->flags );
 548 }
 549
 550 /* duplicate a handle */
 551 DECL_HANDLER(dup_handle)
 552 {
 553     struct process *src, *dst;
 554
 555     reply->handle = 0;
 556     if ((src = get_process_from_handle( req->src_process, PROCESS_DUP_HANDLE )))
 557     {
 558         if (req->options & DUP_HANDLE_MAKE_GLOBAL)
 559         {
 560             reply->handle = duplicate_handle( src, req->src_handle, NULL,
 561                                               req->access, req->attributes, req->options );
 562         }
 563         else if ((dst = get_process_from_handle( req->dst_process, PROCESS_DUP_HANDLE )))
 564         {
 565             reply->handle = duplicate_handle( src, req->src_handle, dst,
 566                                               req->access, req->attributes, req->options );
 567             release_object( dst );
 568         }
 569         /* close the handle no matter what happened */
 570         if (req->options & DUP_HANDLE_CLOSE_SOURCE)
 571         {
 572             unsigned int err = get_error();  /* don't overwrite error from the above calls */
 573             reply->closed = close_handle( src, req->src_handle );
 574             set_error( err );
 575         }
 576         reply->self = (src == current->process);
 577         release_object( src );
 578     }
 579 }
 580
 581 DECL_HANDLER(get_object_info)
 582 {
 583     struct object *obj;
 584
 585     if (!(obj = get_handle_obj( current->process, req->handle, 0, NULL ))) return;
 586
 587     reply->access = get_handle_access( current->process, req->handle );
 588     reply->ref_count = obj->refcount;
 589     release_object( obj );
 590 }