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 "windef.h"
  32 #include "winbase.h"
  33
  34 #include "handle.h"
  35 #include "process.h"
  36 #include "thread.h"
  37 #include "request.h"
  38
  39 struct handle_entry
  40 {
  41     struct object *ptr;       /* object */
  42     unsigned int   access;    /* access rights */
  43     int            fd;        /* file descriptor (in client process) */
  44 };
  45
  46 struct handle_table
  47 {
  48     struct object        obj;         /* object header */
  49     struct process      *process;     /* process owning this table */
  50     int                  count;       /* number of allocated entries */
  51     int                  last;        /* last used entry */
  52     int                  free;        /* first entry that may be free */
  53     struct handle_entry *entries;     /* handle entries */
  54 };
  55
  56 static struct handle_table *global_table;
  57
  58 /* reserved handle access rights */
  59 #define RESERVED_SHIFT         25
  60 #define RESERVED_INHERIT       (HANDLE_FLAG_INHERIT << RESERVED_SHIFT)
  61 #define RESERVED_CLOSE_PROTECT (HANDLE_FLAG_PROTECT_FROM_CLOSE << RESERVED_SHIFT)
  62 #define RESERVED_ALL           (RESERVED_INHERIT | RESERVED_CLOSE_PROTECT)
  63
  64 #define MIN_HANDLE_ENTRIES  32
  65
  66
  67 /* handle to table index conversion */
  68
  69 /* handles are a multiple of 4 under NT; handle 0 is not used */
  70 inline static obj_handle_t index_to_handle( int index )
  71 {
  72     return (obj_handle_t)((index + 1) << 2);
  73 }
  74 inline static int handle_to_index( obj_handle_t handle )
  75 {
  76     return ((unsigned int)handle >> 2) - 1;
  77 }
  78
  79 /* global handle conversion */
  80
  81 #define HANDLE_OBFUSCATOR 0x544a4def
  82
  83 inline static int handle_is_global( obj_handle_t handle)
  84 {
  85     return ((unsigned long)handle ^ HANDLE_OBFUSCATOR) < 0x10000;
  86 }
  87 inline static obj_handle_t handle_local_to_global( obj_handle_t handle )
  88 {
  89     if (!handle) return 0;
  90     return (obj_handle_t)((unsigned long)handle ^ HANDLE_OBFUSCATOR);
  91 }
  92 inline static obj_handle_t handle_global_to_local( obj_handle_t handle )
  93 {
  94     return (obj_handle_t)((unsigned long)handle ^ HANDLE_OBFUSCATOR);
  95 }
  96
  97
  98 static void handle_table_dump( struct object *obj, int verbose );
  99 static void handle_table_destroy( struct object *obj );
 100
 101 static const struct object_ops handle_table_ops =
 102 {
 103     sizeof(struct handle_table),     /* size */
 104     handle_table_dump,               /* dump */
 105     no_add_queue,                    /* add_queue */
 106     NULL,                            /* remove_queue */
 107     NULL,                            /* signaled */
 108     NULL,                            /* satisfied */
 109     no_get_fd,                       /* get_fd */
 110     handle_table_destroy             /* destroy */
 111 };
 112
 113 /* dump a handle table */
 114 static void handle_table_dump( struct object *obj, int verbose )
 115 {
 116     int i;
 117     struct handle_table *table = (struct handle_table *)obj;
 118     struct handle_entry *entry = table->entries;
 119
 120     assert( obj->ops == &handle_table_ops );
 121
 122     fprintf( stderr, "Handle table last=%d count=%d process=%p\n",
 123              table->last, table->count, table->process );
 124     if (!verbose) return;
 125     entry = table->entries;
 126     for (i = 0; i <= table->last; i++, entry++)
 127     {
 128         if (!entry->ptr) continue;
 129         fprintf( stderr, "%9u: %p %08x ",
 130                  (unsigned int)index_to_handle(i), entry->ptr, entry->access );
 131         entry->ptr->ops->dump( entry->ptr, 0 );
 132     }
 133 }
 134
 135 /* destroy a handle table */
 136 static void handle_table_destroy( struct object *obj )
 137 {
 138     int i;
 139     struct handle_table *table = (struct handle_table *)obj;
 140     struct handle_entry *entry = table->entries;
 141
 142     assert( obj->ops == &handle_table_ops );
 143
 144     for (i = 0; i <= table->last; i++, entry++)
 145     {
 146         struct object *obj = entry->ptr;
 147         entry->ptr = NULL;
 148         if (obj) release_object( obj );
 149     }
 150     free( table->entries );
 151 }
 152
 153 /* allocate a new handle table */
 154 struct handle_table *alloc_handle_table( struct process *process, int count )
 155 {
 156     struct handle_table *table;
 157
 158     if (count < MIN_HANDLE_ENTRIES) count = MIN_HANDLE_ENTRIES;
 159     if (!(table = alloc_object( &handle_table_ops )))
 160         return NULL;
 161     table->process = process;
 162     table->count   = count;
 163     table->last    = -1;
 164     table->free    = 0;
 165     if ((table->entries = mem_alloc( count * sizeof(*table->entries) ))) return table;
 166     release_object( table );
 167     return NULL;
 168 }
 169
 170 /* grow a handle table */
 171 static int grow_handle_table( struct handle_table *table )
 172 {
 173     struct handle_entry *new_entries;
 174     int count = table->count;
 175
 176     if (count >= INT_MAX / 2) return 0;
 177     count *= 2;
 178     if (!(new_entries = realloc( table->entries, count * sizeof(struct handle_entry) )))
 179     {
 180         set_error( STATUS_NO_MEMORY );
 181         return 0;
 182     }
 183     table->entries = new_entries;
 184     table->count   = count;
 185     return 1;
 186 }
 187
 188 /* allocate the first free entry in the handle table */
 189 static obj_handle_t alloc_entry( struct handle_table *table, void *obj, unsigned int access )
 190 {
 191     struct handle_entry *entry = table->entries + table->free;
 192     int i;
 193
 194     for (i = table->free; i <= table->last; i++, entry++) if (!entry->ptr) goto found;
 195     if (i >= table->count)
 196     {
 197         if (!grow_handle_table( table )) return 0;
 198         entry = table->entries + i;  /* the entries may have moved */
 199     }
 200     table->last = i;
 201  found:
 202     table->free = i + 1;
 203     entry->ptr    = grab_object( obj );
 204     entry->access = access;
 205     entry->fd     = -1;
 206     return index_to_handle(i);
 207 }
 208
 209 /* allocate a handle for an object, incrementing its refcount */
 210 /* return the handle, or 0 on error */
 211 obj_handle_t alloc_handle( struct process *process, void *obj, unsigned int access, int inherit )
 212 {
 213     struct handle_table *table = process->handles;
 214
 215     assert( table );
 216     assert( !(access & RESERVED_ALL) );
 217     if (inherit) access |= RESERVED_INHERIT;
 218     return alloc_entry( table, obj, access );
 219 }
 220
 221 /* allocate a global handle for an object, incrementing its refcount */
 222 /* return the handle, or 0 on error */
 223 static obj_handle_t alloc_global_handle( void *obj, unsigned int access )
 224 {
 225     if (!global_table)
 226     {
 227         if (!(global_table = (struct handle_table *)alloc_handle_table( NULL, 0 )))
 228             return 0;
 229     }
 230     return handle_local_to_global( alloc_entry( global_table, obj, access ));
 231 }
 232
 233 /* return a handle entry, or NULL if the handle is invalid */
 234 static struct handle_entry *get_handle( struct process *process, obj_handle_t handle )
 235 {
 236     struct handle_table *table = process->handles;
 237     struct handle_entry *entry;
 238     int index;
 239
 240     if (handle_is_global(handle))
 241     {
 242         handle = handle_global_to_local(handle);
 243         table = global_table;
 244     }
 245     if (!table) goto error;
 246     index = handle_to_index( handle );
 247     if (index < 0) goto error;
 248     if (index > table->last) goto error;
 249     entry = table->entries + index;
 250     if (!entry->ptr) goto error;
 251     return entry;
 252
 253  error:
 254     set_error( STATUS_INVALID_HANDLE );
 255     return NULL;
 256 }
 257
 258 /* attempt to shrink a table */
 259 static void shrink_handle_table( struct handle_table *table )
 260 {
 261     struct handle_entry *entry = table->entries + table->last;
 262     struct handle_entry *new_entries;
 263     int count = table->count;
 264
 265     while (table->last >= 0)
 266     {
 267         if (entry->ptr) break;
 268         table->last--;
 269         entry--;
 270     }
 271     if (table->last >= count / 4) return;  /* no need to shrink */
 272     if (count < MIN_HANDLE_ENTRIES * 2) return;  /* too small to shrink */
 273     count /= 2;
 274     if (!(new_entries = realloc( table->entries, count * sizeof(*new_entries) ))) return;
 275     table->count   = count;
 276     table->entries = new_entries;
 277 }
 278
 279 /* copy the handle table of the parent process */
 280 /* return 1 if OK, 0 on error */
 281 struct handle_table *copy_handle_table( struct process *process, struct process *parent )
 282 {
 283     struct handle_table *parent_table = parent->handles;
 284     struct handle_table *table;
 285     int i;
 286
 287     assert( parent_table );
 288     assert( parent_table->obj.ops == &handle_table_ops );
 289
 290     if (!(table = (struct handle_table *)alloc_handle_table( process, parent_table->count )))
 291         return NULL;
 292
 293     if ((table->last = parent_table->last) >= 0)
 294     {
 295         struct handle_entry *ptr = table->entries;
 296         memcpy( ptr, parent_table->entries, (table->last + 1) * sizeof(struct handle_entry) );
 297         for (i = 0; i <= table->last; i++, ptr++)
 298         {
 299             if (!ptr->ptr) continue;
 300             ptr->fd = -1;
 301             if (ptr->access & RESERVED_INHERIT) grab_object( ptr->ptr );
 302             else ptr->ptr = NULL; /* don't inherit this entry */
 303         }
 304     }
 305     /* attempt to shrink the table */
 306     shrink_handle_table( table );
 307     return table;
 308 }
 309
 310 /* close a handle and decrement the refcount of the associated object */
 311 /* return 1 if OK, 0 on error */
 312 int close_handle( struct process *process, obj_handle_t handle, int *fd )
 313 {
 314     struct handle_table *table;
 315     struct handle_entry *entry;
 316     struct object *obj;
 317
 318     if (!(entry = get_handle( process, handle ))) return 0;
 319     if (entry->access & RESERVED_CLOSE_PROTECT)
 320     {
 321         set_error( STATUS_INVALID_HANDLE );
 322         return 0;
 323     }
 324     obj = entry->ptr;
 325     entry->ptr = NULL;
 326     if (fd) *fd = entry->fd;
 327     else if (entry->fd != -1) return 1;  /* silently ignore close attempt if we cannot close the fd */
 328     entry->fd = -1;
 329     table = handle_is_global(handle) ? global_table : process->handles;
 330     if (entry < table->entries + table->free) table->free = entry - table->entries;
 331     if (entry == table->entries + table->last) shrink_handle_table( table );
 332     /* hack: windows seems to treat registry handles differently */
 333     registry_close_handle( obj, handle );
 334     release_object( obj );
 335     return 1;
 336 }
 337
 338 /* close all the global handles */
 339 void close_global_handles(void)
 340 {
 341     if (global_table)
 342     {
 343         release_object( global_table );
 344         global_table = NULL;
 345     }
 346 }
 347
 348 /* retrieve the object corresponding to one of the magic pseudo-handles */
 349 static inline struct object *get_magic_handle( obj_handle_t handle )
 350 {
 351     switch((unsigned long)handle)
 352     {
 353         case 0xfffffffe:  /* current thread pseudo-handle */
 354             return &current->obj;
 355         case 0x7fffffff:  /* current process pseudo-handle */
 356         case 0xffffffff:  /* current process pseudo-handle */
 357             return (struct object *)current->process;
 358         default:
 359             return NULL;
 360     }
 361 }
 362
 363 /* retrieve the object corresponding to a handle, incrementing its refcount */
 364 struct object *get_handle_obj( struct process *process, obj_handle_t handle,
 365                                unsigned int access, const struct object_ops *ops )
 366 {
 367     struct handle_entry *entry;
 368     struct object *obj;
 369
 370     if (!(obj = get_magic_handle( handle )))
 371     {
 372         if (!(entry = get_handle( process, handle ))) return NULL;
 373         if ((entry->access & access) != access)
 374         {
 375             set_error( STATUS_ACCESS_DENIED );
 376             return NULL;
 377         }
 378         obj = entry->ptr;
 379     }
 380     if (ops && (obj->ops != ops))
 381     {
 382         set_error( STATUS_OBJECT_TYPE_MISMATCH );  /* not the right type */
 383         return NULL;
 384     }
 385     return grab_object( obj );
 386 }
 387
 388 /* retrieve the cached fd for a given handle */
 389 int get_handle_unix_fd( struct process *process, obj_handle_t handle, unsigned int access )
 390 {
 391     struct handle_entry *entry;
 392
 393     if (!(entry = get_handle( process, handle ))) return -1;
 394     if ((entry->access & access) != access)
 395     {
 396         set_error( STATUS_ACCESS_DENIED );
 397         return -1;
 398     }
 399     return entry->fd;
 400 }
 401
 402 /* remove the cached fd and return it */
 403 int flush_cached_fd( struct process *process, obj_handle_t handle )
 404 {
 405     struct handle_entry *entry = get_handle( process, handle );
 406     int fd = -1;
 407
 408     if (entry)
 409     {
 410         fd = entry->fd;
 411         entry->fd = -1;
 412     }
 413     return fd;
 414 }
 415
 416 /* find the first inherited handle of the given type */
 417 /* this is needed for window stations and desktops (don't ask...) */
 418 obj_handle_t find_inherited_handle( struct process *process, const struct object_ops *ops )
 419 {
 420     struct handle_table *table = process->handles;
 421     struct handle_entry *ptr;
 422     int i;
 423
 424     if (!table) return 0;
 425
 426     for (i = 0, ptr = table->entries; i <= table->last; i++, ptr++)
 427     {
 428         if (!ptr->ptr) continue;
 429         if (ptr->ptr->ops != ops) continue;
 430         if (ptr->access & RESERVED_INHERIT) return index_to_handle(i);
 431     }
 432     return 0;
 433 }
 434
 435 /* get/set the handle reserved flags */
 436 /* return the old flags (or -1 on error) */
 437 int set_handle_info( struct process *process, obj_handle_t handle, int mask, int flags, int *fd )
 438 {
 439     struct handle_entry *entry;
 440     unsigned int old_access;
 441
 442     if (get_magic_handle( handle ))
 443     {
 444         /* we can retrieve but not set info for magic handles */
 445         if (mask) set_error( STATUS_ACCESS_DENIED );
 446         return 0;
 447     }
 448     if (!(entry = get_handle( process, handle ))) return -1;
 449     old_access = entry->access;
 450     mask  = (mask << RESERVED_SHIFT) & RESERVED_ALL;
 451     flags = (flags << RESERVED_SHIFT) & mask;
 452     entry->access = (entry->access & ~mask) | flags;
 453     /* if no current fd set it, otherwise return current fd */
 454     if (entry->fd == -1) entry->fd = *fd;
 455     *fd = entry->fd;
 456     return (old_access & RESERVED_ALL) >> RESERVED_SHIFT;
 457 }
 458
 459 /* duplicate a handle */
 460 obj_handle_t duplicate_handle( struct process *src, obj_handle_t src_handle, struct process *dst,
 461                            unsigned int access, int inherit, int options )
 462 {
 463     obj_handle_t res;
 464     struct object *obj = get_handle_obj( src, src_handle, 0, NULL );
 465
 466     if (!obj) return 0;
 467     if (options & DUP_HANDLE_SAME_ACCESS)
 468     {
 469         struct handle_entry *entry = get_handle( src, src_handle );
 470         if (entry)
 471             access = entry->access;
 472         else  /* pseudo-handle, give it full access */
 473         {
 474             access = STANDARD_RIGHTS_ALL | SPECIFIC_RIGHTS_ALL;
 475             clear_error();
 476         }
 477     }
 478     access &= ~RESERVED_ALL;
 479     if (options & DUP_HANDLE_MAKE_GLOBAL)
 480         res = alloc_global_handle( obj, access );
 481     else
 482         res = alloc_handle( dst, obj, access, inherit );
 483     release_object( obj );
 484     return res;
 485 }
 486
 487 /* open a new handle to an existing object */
 488 obj_handle_t open_object( const struct namespace *namespace, const WCHAR *name, size_t len,
 489                           const struct object_ops *ops, unsigned int access, int inherit )
 490 {
 491     obj_handle_t handle = 0;
 492     struct object *obj = find_object( namespace, name, len );
 493     if (obj)
 494     {
 495         if (ops && obj->ops != ops)
 496             set_error( STATUS_OBJECT_TYPE_MISMATCH );
 497         else
 498             handle = alloc_handle( current->process, obj, access, inherit );
 499         release_object( obj );
 500     }
 501     else
 502         set_error( STATUS_OBJECT_NAME_NOT_FOUND );
 503     return handle;
 504 }
 505
 506 /* return the size of the handle table of a given process */
 507 unsigned int get_handle_table_count( struct process *process )
 508 {
 509     return process->handles->count;
 510 }
 511
 512 /* close a handle */
 513 DECL_HANDLER(close_handle)
 514 {
 515     close_handle( current->process, req->handle, &reply->fd );
 516 }
 517
 518 /* set a handle information */
 519 DECL_HANDLER(set_handle_info)
 520 {
 521     int fd = req->fd;
 522
 523     if (handle_is_global(req->handle)) fd = -1;  /* no fd cache for global handles */
 524     reply->old_flags = set_handle_info( current->process, req->handle,
 525                                         req->mask, req->flags, &fd );
 526     reply->cur_fd = fd;
 527 }
 528
 529 /* duplicate a handle */
 530 DECL_HANDLER(dup_handle)
 531 {
 532     struct process *src, *dst;
 533
 534     reply->handle = 0;
 535     reply->fd = -1;
 536     if ((src = get_process_from_handle( req->src_process, PROCESS_DUP_HANDLE )))
 537     {
 538         if (req->options & DUP_HANDLE_MAKE_GLOBAL)
 539         {
 540             reply->handle = duplicate_handle( src, req->src_handle, NULL,
 541                                               req->access, req->inherit, req->options );
 542         }
 543         else if ((dst = get_process_from_handle( req->dst_process, PROCESS_DUP_HANDLE )))
 544         {
 545             reply->handle = duplicate_handle( src, req->src_handle, dst,
 546                                               req->access, req->inherit, req->options );
 547             release_object( dst );
 548         }
 549         /* close the handle no matter what happened */
 550         if (req->options & DUP_HANDLE_CLOSE_SOURCE)
 551         {
 552             if (src == current->process) close_handle( src, req->src_handle, &reply->fd );
 553             else close_handle( src, req->src_handle, NULL );
 554         }
 555         release_object( src );
 556     }
 557 }