File: mapping.c

package info (click to toggle)
wine 1.4.1-4
  • links: PTS, VCS
  • area: main
  • in suites: wheezy
  • size: 156,772 kB
  • sloc: ansic: 2,124,295; perl: 17,673; yacc: 12,202; makefile: 7,447; sh: 3,981; lex: 3,913; cpp: 812; awk: 69; xml: 21; sed: 3
file content (771 lines) | stat: -rw-r--r-- 25,425 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
/*
 * Server-side file mapping management
 *
 * Copyright (C) 1999 Alexandre Julliard
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include "config.h"
#include "wine/port.h"

#include <assert.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_MMAN_H
# include <sys/mman.h>
#endif
#include <unistd.h>

#include "ntstatus.h"
#define WIN32_NO_STATUS
#include "windef.h"
#include "winternl.h"

#include "file.h"
#include "handle.h"
#include "thread.h"
#include "request.h"
#include "security.h"

/* list of memory ranges, used to store committed info */
struct ranges
{
    unsigned int count;
    unsigned int max;
    struct range
    {
        file_pos_t  start;
        file_pos_t  end;
    } ranges[1];
};

struct mapping
{
    struct object   obj;             /* object header */
    mem_size_t      size;            /* mapping size */
    int             protect;         /* protection flags */
    struct fd      *fd;              /* fd for mapped file */
    int             header_size;     /* size of headers (for PE image mapping) */
    client_ptr_t    base;            /* default base addr (for PE image mapping) */
    struct ranges  *committed;       /* list of committed ranges in this mapping */
    struct file    *shared_file;     /* temp file for shared PE mapping */
    struct list     shared_entry;    /* entry in global shared PE mappings list */
};

static void mapping_dump( struct object *obj, int verbose );
static struct object_type *mapping_get_type( struct object *obj );
static struct fd *mapping_get_fd( struct object *obj );
static unsigned int mapping_map_access( struct object *obj, unsigned int access );
static void mapping_destroy( struct object *obj );
static enum server_fd_type mapping_get_fd_type( struct fd *fd );

static const struct object_ops mapping_ops =
{
    sizeof(struct mapping),      /* size */
    mapping_dump,                /* dump */
    mapping_get_type,            /* get_type */
    no_add_queue,                /* add_queue */
    NULL,                        /* remove_queue */
    NULL,                        /* signaled */
    NULL,                        /* satisfied */
    no_signal,                   /* signal */
    mapping_get_fd,              /* get_fd */
    mapping_map_access,          /* map_access */
    default_get_sd,              /* get_sd */
    default_set_sd,              /* set_sd */
    no_lookup_name,              /* lookup_name */
    no_open_file,                /* open_file */
    fd_close_handle,             /* close_handle */
    mapping_destroy              /* destroy */
};

static const struct fd_ops mapping_fd_ops =
{
    default_fd_get_poll_events,   /* get_poll_events */
    default_poll_event,           /* poll_event */
    no_flush,                     /* flush */
    mapping_get_fd_type,          /* get_fd_type */
    no_fd_ioctl,                  /* ioctl */
    no_fd_queue_async,            /* queue_async */
    default_fd_reselect_async,    /* reselect_async */
    default_fd_cancel_async       /* cancel_async */
};

static struct list shared_list = LIST_INIT(shared_list);

#ifdef __i386__

/* These are always the same on an i386, and it will be faster this way */
# define page_mask  0xfff
# define page_shift 12
# define init_page_size() do { /* nothing */ } while(0)

#else  /* __i386__ */

static int page_shift, page_mask;

static void init_page_size(void)
{
    int page_size;
# ifdef HAVE_GETPAGESIZE
    page_size = getpagesize();
# else
#  ifdef __svr4__
    page_size = sysconf(_SC_PAGESIZE);
#  else
#   error Cannot get the page size on this platform
#  endif
# endif
    page_mask = page_size - 1;
    /* Make sure we have a power of 2 */
    assert( !(page_size & page_mask) );
    page_shift = 0;
    while ((1 << page_shift) != page_size) page_shift++;
}
#endif  /* __i386__ */

#define ROUND_SIZE(size)  (((size) + page_mask) & ~page_mask)


/* extend a file beyond the current end of file */
static int grow_file( int unix_fd, file_pos_t new_size )
{
    static const char zero;
    off_t size = new_size;

    if (sizeof(new_size) > sizeof(size) && size != new_size)
    {
        set_error( STATUS_INVALID_PARAMETER );
        return 0;
    }
    /* extend the file one byte beyond the requested size and then truncate it */
    /* this should work around ftruncate implementations that can't extend files */
    if (pwrite( unix_fd, &zero, 1, size ) != -1)
    {
        ftruncate( unix_fd, size );
        return 1;
    }
    file_set_error();
    return 0;
}

/* check if the current directory allows exec mappings */
static int check_current_dir_for_exec(void)
{
    int fd;
    char tmpfn[] = "anonmap.XXXXXX";
    void *ret = MAP_FAILED;

    fd = mkstemps( tmpfn, 0 );
    if (fd == -1) return 0;
    if (grow_file( fd, 1 ))
    {
        ret = mmap( NULL, get_page_size(), PROT_READ | PROT_EXEC, MAP_PRIVATE, fd, 0 );
        if (ret != MAP_FAILED) munmap( ret, get_page_size() );
    }
    close( fd );
    unlink( tmpfn );
    return (ret != MAP_FAILED);
}

/* create a temp file for anonymous mappings */
static int create_temp_file( file_pos_t size )
{
    static int temp_dir_fd = -1;
    char tmpfn[] = "anonmap.XXXXXX";
    int fd;

    if (temp_dir_fd == -1)
    {
        temp_dir_fd = server_dir_fd;
        if (!check_current_dir_for_exec())
        {
            /* the server dir is noexec, try the config dir instead */
            fchdir( config_dir_fd );
            if (check_current_dir_for_exec())
                temp_dir_fd = config_dir_fd;
            else  /* neither works, fall back to server dir */
                fchdir( server_dir_fd );
        }
    }
    else if (temp_dir_fd != server_dir_fd) fchdir( temp_dir_fd );

    fd = mkstemps( tmpfn, 0 );
    if (fd != -1)
    {
        if (!grow_file( fd, size ))
        {
            close( fd );
            fd = -1;
        }
        unlink( tmpfn );
    }
    else file_set_error();

    if (temp_dir_fd != server_dir_fd) fchdir( server_dir_fd );
    return fd;
}

/* find the shared PE mapping for a given mapping */
static struct file *get_shared_file( struct mapping *mapping )
{
    struct mapping *ptr;

    LIST_FOR_EACH_ENTRY( ptr, &shared_list, struct mapping, shared_entry )
        if (is_same_file_fd( ptr->fd, mapping->fd ))
            return (struct file *)grab_object( ptr->shared_file );
    return NULL;
}

/* return the size of the memory mapping and file range of a given section */
static inline void get_section_sizes( const IMAGE_SECTION_HEADER *sec, size_t *map_size,
                                      off_t *file_start, size_t *file_size )
{
    static const unsigned int sector_align = 0x1ff;

    if (!sec->Misc.VirtualSize) *map_size = ROUND_SIZE( sec->SizeOfRawData );
    else *map_size = ROUND_SIZE( sec->Misc.VirtualSize );

    *file_start = sec->PointerToRawData & ~sector_align;
    *file_size = (sec->SizeOfRawData + (sec->PointerToRawData & sector_align) + sector_align) & ~sector_align;
    if (*file_size > *map_size) *file_size = *map_size;
}

/* add a range to the committed list */
static void add_committed_range( struct mapping *mapping, file_pos_t start, file_pos_t end )
{
    unsigned int i, j;
    struct range *ranges;

    if (!mapping->committed) return;  /* everything committed already */

    for (i = 0, ranges = mapping->committed->ranges; i < mapping->committed->count; i++)
    {
        if (ranges[i].start > end) break;
        if (ranges[i].end < start) continue;
        if (ranges[i].start > start) ranges[i].start = start;   /* extend downwards */
        if (ranges[i].end < end)  /* extend upwards and maybe merge with next */
        {
            for (j = i + 1; j < mapping->committed->count; j++)
            {
                if (ranges[j].start > end) break;
                if (ranges[j].end > end) end = ranges[j].end;
            }
            if (j > i + 1)
            {
                memmove( &ranges[i + 1], &ranges[j], (mapping->committed->count - j) * sizeof(*ranges) );
                mapping->committed->count -= j - (i + 1);
            }
            ranges[i].end = end;
        }
        return;
    }

    /* now add a new range */

    if (mapping->committed->count == mapping->committed->max)
    {
        unsigned int new_size = mapping->committed->max * 2;
        struct ranges *new_ptr = realloc( mapping->committed, offsetof( struct ranges, ranges[new_size] ));
        if (!new_ptr) return;
        new_ptr->max = new_size;
        ranges = new_ptr->ranges;
        mapping->committed = new_ptr;
    }
    memmove( &ranges[i + 1], &ranges[i], (mapping->committed->count - i) * sizeof(*ranges) );
    ranges[i].start = start;
    ranges[i].end = end;
    mapping->committed->count++;
}

/* find the range containing start and return whether it's committed */
static int find_committed_range( struct mapping *mapping, file_pos_t start, mem_size_t *size )
{
    unsigned int i;
    struct range *ranges;

    if (!mapping->committed)  /* everything is committed */
    {
        *size = mapping->size - start;
        return 1;
    }
    for (i = 0, ranges = mapping->committed->ranges; i < mapping->committed->count; i++)
    {
        if (ranges[i].start > start)
        {
            *size = ranges[i].start - start;
            return 0;
        }
        if (ranges[i].end > start)
        {
            *size = ranges[i].end - start;
            return 1;
        }
    }
    *size = mapping->size - start;
    return 0;
}

/* allocate and fill the temp file for a shared PE image mapping */
static int build_shared_mapping( struct mapping *mapping, int fd,
                                 IMAGE_SECTION_HEADER *sec, unsigned int nb_sec )
{
    unsigned int i;
    mem_size_t total_size;
    size_t file_size, map_size, max_size;
    off_t shared_pos, read_pos, write_pos;
    char *buffer = NULL;
    int shared_fd;
    long toread;

    /* compute the total size of the shared mapping */

    total_size = max_size = 0;
    for (i = 0; i < nb_sec; i++)
    {
        if ((sec[i].Characteristics & IMAGE_SCN_MEM_SHARED) &&
            (sec[i].Characteristics & IMAGE_SCN_MEM_WRITE))
        {
            get_section_sizes( &sec[i], &map_size, &read_pos, &file_size );
            if (file_size > max_size) max_size = file_size;
            total_size += map_size;
        }
    }
    if (!total_size) return 1;  /* nothing to do */

    if ((mapping->shared_file = get_shared_file( mapping ))) return 1;

    /* create a temp file for the mapping */

    if ((shared_fd = create_temp_file( total_size )) == -1) return 0;
    if (!(mapping->shared_file = create_file_for_fd( shared_fd, FILE_GENERIC_READ|FILE_GENERIC_WRITE, 0 )))
        return 0;

    if (!(buffer = malloc( max_size ))) goto error;

    /* copy the shared sections data into the temp file */

    shared_pos = 0;
    for (i = 0; i < nb_sec; i++)
    {
        if (!(sec[i].Characteristics & IMAGE_SCN_MEM_SHARED)) continue;
        if (!(sec[i].Characteristics & IMAGE_SCN_MEM_WRITE)) continue;
        get_section_sizes( &sec[i], &map_size, &read_pos, &file_size );
        write_pos = shared_pos;
        shared_pos += map_size;
        if (!sec[i].PointerToRawData || !file_size) continue;
        toread = file_size;
        while (toread)
        {
            long res = pread( fd, buffer + file_size - toread, toread, read_pos );
            if (!res && toread < 0x200)  /* partial sector at EOF is not an error */
            {
                file_size -= toread;
                break;
            }
            if (res <= 0) goto error;
            toread -= res;
            read_pos += res;
        }
        if (pwrite( shared_fd, buffer, file_size, write_pos ) != file_size) goto error;
    }
    free( buffer );
    return 1;

 error:
    release_object( mapping->shared_file );
    mapping->shared_file = NULL;
    free( buffer );
    return 0;
}

/* retrieve the mapping parameters for an executable (PE) image */
static int get_image_params( struct mapping *mapping, int unix_fd, int protect )
{
    IMAGE_DOS_HEADER dos;
    IMAGE_SECTION_HEADER *sec = NULL;
    struct
    {
        DWORD Signature;
        IMAGE_FILE_HEADER FileHeader;
        union
        {
            IMAGE_OPTIONAL_HEADER32 hdr32;
            IMAGE_OPTIONAL_HEADER64 hdr64;
        } opt;
    } nt;
    off_t pos;
    int size;

    /* load the headers */

    if (pread( unix_fd, &dos, sizeof(dos), 0 ) != sizeof(dos)) goto error;
    if (dos.e_magic != IMAGE_DOS_SIGNATURE) goto error;
    pos = dos.e_lfanew;

    size = pread( unix_fd, &nt, sizeof(nt), pos );
    if (size < sizeof(nt.Signature) + sizeof(nt.FileHeader)) goto error;
    /* zero out Optional header in the case it's not present or partial */
    if (size < sizeof(nt)) memset( (char *)&nt + size, 0, sizeof(nt) - size );
    if (nt.Signature != IMAGE_NT_SIGNATURE) goto error;

    switch (nt.opt.hdr32.Magic)
    {
    case IMAGE_NT_OPTIONAL_HDR32_MAGIC:
        mapping->size        = ROUND_SIZE( nt.opt.hdr32.SizeOfImage );
        mapping->base        = nt.opt.hdr32.ImageBase;
        mapping->header_size = nt.opt.hdr32.SizeOfHeaders;
        break;
    case IMAGE_NT_OPTIONAL_HDR64_MAGIC:
        mapping->size        = ROUND_SIZE( nt.opt.hdr64.SizeOfImage );
        mapping->base        = nt.opt.hdr64.ImageBase;
        mapping->header_size = nt.opt.hdr64.SizeOfHeaders;
        break;
    default:
        goto error;
    }

    /* load the section headers */

    pos += sizeof(nt.Signature) + sizeof(nt.FileHeader) + nt.FileHeader.SizeOfOptionalHeader;
    size = sizeof(*sec) * nt.FileHeader.NumberOfSections;
    if (pos + size > mapping->size) goto error;
    if (pos + size > mapping->header_size) mapping->header_size = pos + size;
    if (!(sec = malloc( size ))) goto error;
    if (pread( unix_fd, sec, size, pos ) != size) goto error;

    if (!build_shared_mapping( mapping, unix_fd, sec, nt.FileHeader.NumberOfSections )) goto error;

    if (mapping->shared_file) list_add_head( &shared_list, &mapping->shared_entry );

    mapping->protect = protect;
    free( sec );
    return 1;

 error:
    free( sec );
    set_error( STATUS_INVALID_FILE_FOR_SECTION );
    return 0;
}

static struct object *create_mapping( struct directory *root, const struct unicode_str *name,
                                      unsigned int attr, mem_size_t size, int protect,
                                      obj_handle_t handle, const struct security_descriptor *sd )
{
    struct mapping *mapping;
    struct file *file;
    struct fd *fd;
    int access = 0;
    int unix_fd;
    struct stat st;

    if (!page_mask) init_page_size();

    if (!(mapping = create_named_object_dir( root, name, attr, &mapping_ops )))
        return NULL;
    if (get_error() == STATUS_OBJECT_NAME_EXISTS)
        return &mapping->obj;  /* Nothing else to do */

    if (sd) default_set_sd( &mapping->obj, sd, OWNER_SECURITY_INFORMATION|
                                               GROUP_SECURITY_INFORMATION|
                                               DACL_SECURITY_INFORMATION|
                                               SACL_SECURITY_INFORMATION );
    mapping->header_size = 0;
    mapping->base        = 0;
    mapping->fd          = NULL;
    mapping->shared_file = NULL;
    mapping->committed   = NULL;

    if (protect & VPROT_READ) access |= FILE_READ_DATA;
    if (protect & VPROT_WRITE) access |= FILE_WRITE_DATA;

    if (handle)
    {
        const unsigned int sharing = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
        unsigned int mapping_access = FILE_MAPPING_ACCESS;

        if (!(protect & VPROT_COMMITTED))
        {
            set_error( STATUS_INVALID_PARAMETER );
            goto error;
        }
        if (!(file = get_file_obj( current->process, handle, access ))) goto error;
        fd = get_obj_fd( (struct object *)file );

        /* file sharing rules for mappings are different so we use magic the access rights */
        if (protect & VPROT_IMAGE) mapping_access |= FILE_MAPPING_IMAGE;
        else if (protect & VPROT_WRITE) mapping_access |= FILE_MAPPING_WRITE;

        if (!(mapping->fd = get_fd_object_for_mapping( fd, mapping_access, sharing )))
        {
            mapping->fd = dup_fd_object( fd, mapping_access, sharing, FILE_SYNCHRONOUS_IO_NONALERT );
            if (mapping->fd) set_fd_user( mapping->fd, &mapping_fd_ops, NULL );
        }
        release_object( file );
        release_object( fd );
        if (!mapping->fd) goto error;

        if ((unix_fd = get_unix_fd( mapping->fd )) == -1) goto error;
        if (protect & VPROT_IMAGE)
        {
            if (!get_image_params( mapping, unix_fd, protect )) goto error;
            return &mapping->obj;
        }
        if (fstat( unix_fd, &st ) == -1)
        {
            file_set_error();
            goto error;
        }
        if (!size)
        {
            if (!(size = st.st_size))
            {
                set_error( STATUS_MAPPED_FILE_SIZE_ZERO );
                goto error;
            }
        }
        else if (st.st_size < size && !grow_file( unix_fd, size )) goto error;
    }
    else  /* Anonymous mapping (no associated file) */
    {
        if (!size || (protect & VPROT_IMAGE))
        {
            set_error( STATUS_INVALID_PARAMETER );
            goto error;
        }
        if (!(protect & VPROT_COMMITTED))
        {
            if (!(mapping->committed = mem_alloc( offsetof(struct ranges, ranges[8]) ))) goto error;
            mapping->committed->count = 0;
            mapping->committed->max   = 8;
        }
        if ((unix_fd = create_temp_file( size )) == -1) goto error;
        if (!(mapping->fd = create_anonymous_fd( &mapping_fd_ops, unix_fd, &mapping->obj,
                                                 FILE_SYNCHRONOUS_IO_NONALERT ))) goto error;
        allow_fd_caching( mapping->fd );
    }
    mapping->size    = (size + page_mask) & ~((mem_size_t)page_mask);
    mapping->protect = protect;
    return &mapping->obj;

 error:
    release_object( mapping );
    return NULL;
}

struct mapping *get_mapping_obj( struct process *process, obj_handle_t handle, unsigned int access )
{
    return (struct mapping *)get_handle_obj( process, handle, access, &mapping_ops );
}

/* open a new file handle to the file backing the mapping */
obj_handle_t open_mapping_file( struct process *process, struct mapping *mapping,
                                unsigned int access, unsigned int sharing )
{
    obj_handle_t handle;
    struct file *file = create_file_for_fd_obj( mapping->fd, access, sharing );

    if (!file) return 0;
    handle = alloc_handle( process, file, access, 0 );
    release_object( file );
    return handle;
}

struct mapping *grab_mapping_unless_removable( struct mapping *mapping )
{
    if (is_fd_removable( mapping->fd )) return NULL;
    return (struct mapping *)grab_object( mapping );
}

static void mapping_dump( struct object *obj, int verbose )
{
    struct mapping *mapping = (struct mapping *)obj;
    assert( obj->ops == &mapping_ops );
    fprintf( stderr, "Mapping size=%08x%08x prot=%08x fd=%p header_size=%08x base=%08lx "
             "shared_file=%p ",
             (unsigned int)(mapping->size >> 32), (unsigned int)mapping->size,
             mapping->protect, mapping->fd, mapping->header_size,
             (unsigned long)mapping->base, mapping->shared_file );
    dump_object_name( &mapping->obj );
    fputc( '\n', stderr );
}

static struct object_type *mapping_get_type( struct object *obj )
{
    static const WCHAR name[] = {'S','e','c','t','i','o','n'};
    static const struct unicode_str str = { name, sizeof(name) };
    return get_object_type( &str );
}

static struct fd *mapping_get_fd( struct object *obj )
{
    struct mapping *mapping = (struct mapping *)obj;
    return (struct fd *)grab_object( mapping->fd );
}

static unsigned int mapping_map_access( struct object *obj, unsigned int access )
{
    if (access & GENERIC_READ)    access |= STANDARD_RIGHTS_READ | SECTION_QUERY | SECTION_MAP_READ;
    if (access & GENERIC_WRITE)   access |= STANDARD_RIGHTS_WRITE | SECTION_MAP_WRITE;
    if (access & GENERIC_EXECUTE) access |= STANDARD_RIGHTS_EXECUTE | SECTION_MAP_EXECUTE;
    if (access & GENERIC_ALL)     access |= SECTION_ALL_ACCESS;
    return access & ~(GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE | GENERIC_ALL);
}

static void mapping_destroy( struct object *obj )
{
    struct mapping *mapping = (struct mapping *)obj;
    assert( obj->ops == &mapping_ops );
    if (mapping->fd) release_object( mapping->fd );
    if (mapping->shared_file)
    {
        release_object( mapping->shared_file );
        list_remove( &mapping->shared_entry );
    }
    free( mapping->committed );
}

static enum server_fd_type mapping_get_fd_type( struct fd *fd )
{
    return FD_TYPE_FILE;
}

int get_page_size(void)
{
    if (!page_mask) init_page_size();
    return page_mask + 1;
}

/* create a file mapping */
DECL_HANDLER(create_mapping)
{
    struct object *obj;
    struct unicode_str name;
    struct directory *root = NULL;
    const struct object_attributes *objattr = get_req_data();
    const struct security_descriptor *sd;

    reply->handle = 0;

    if (!objattr_is_valid( objattr, get_req_data_size() ))
        return;

    sd = objattr->sd_len ? (const struct security_descriptor *)(objattr + 1) : NULL;
    objattr_get_name( objattr, &name );

    if (objattr->rootdir && !(root = get_directory_obj( current->process, objattr->rootdir, 0 )))
        return;

    if ((obj = create_mapping( root, &name, req->attributes, req->size, req->protect, req->file_handle, sd )))
    {
        if (get_error() == STATUS_OBJECT_NAME_EXISTS)
            reply->handle = alloc_handle( current->process, obj, req->access, req->attributes );
        else
            reply->handle = alloc_handle_no_access_check( current->process, obj, req->access, req->attributes );
        release_object( obj );
    }

    if (root) release_object( root );
}

/* open a handle to a mapping */
DECL_HANDLER(open_mapping)
{
    struct unicode_str name;
    struct directory *root = NULL;
    struct mapping *mapping;

    get_req_unicode_str( &name );
    if (req->rootdir && !(root = get_directory_obj( current->process, req->rootdir, 0 )))
        return;

    if ((mapping = open_object_dir( root, &name, req->attributes, &mapping_ops )))
    {
        reply->handle = alloc_handle( current->process, &mapping->obj, req->access, req->attributes );
        release_object( mapping );
    }

    if (root) release_object( root );
}

/* get a mapping information */
DECL_HANDLER(get_mapping_info)
{
    struct mapping *mapping;
    struct fd *fd;

    if ((mapping = get_mapping_obj( current->process, req->handle, req->access )))
    {
        reply->size        = mapping->size;
        reply->protect     = mapping->protect;
        reply->header_size = mapping->header_size;
        reply->base        = mapping->base;
        reply->shared_file = 0;
        if ((fd = get_obj_fd( &mapping->obj )))
        {
            if (!is_fd_removable(fd))
                reply->mapping = alloc_handle( current->process, mapping, 0, 0 );
            release_object( fd );
        }
        if (mapping->shared_file)
        {
            if (!(reply->shared_file = alloc_handle( current->process, mapping->shared_file,
                                                     GENERIC_READ|GENERIC_WRITE, 0 )))
            {
                if (reply->mapping) close_handle( current->process, reply->mapping );
            }
        }
        release_object( mapping );
    }
}

/* get a range of committed pages in a file mapping */
DECL_HANDLER(get_mapping_committed_range)
{
    struct mapping *mapping;

    if ((mapping = get_mapping_obj( current->process, req->handle, 0 )))
    {
        if (!(req->offset & page_mask) && req->offset < mapping->size)
            reply->committed = find_committed_range( mapping, req->offset, &reply->size );
        else
            set_error( STATUS_INVALID_PARAMETER );

        release_object( mapping );
    }
}

/* add a range to the committed pages in a file mapping */
DECL_HANDLER(add_mapping_committed_range)
{
    struct mapping *mapping;

    if ((mapping = get_mapping_obj( current->process, req->handle, 0 )))
    {
        if (!(req->size & page_mask) &&
            !(req->offset & page_mask) &&
            req->offset < mapping->size &&
            req->size > 0 &&
            req->size <= mapping->size - req->offset)
            add_committed_range( mapping, req->offset, req->offset + req->size );
        else
            set_error( STATUS_INVALID_PARAMETER );

        release_object( mapping );
    }
}