about summary refs log tree commit diff
path: root/libio/fileops.c
blob: 52880c52a9756c3af9c64091cb5efe5cbd166415 (plain) (blame)
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
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
/* Copyright (C) 1993, 1995, 1997-1999, 2000 Free Software Foundation, Inc.
   This file is part of the GNU IO Library.
   Written by Per Bothner <bothner@cygnus.com>.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, 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
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this library; see the file COPYING.  If not, write to
   the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
   MA 02111-1307, USA.

   As a special exception, if you link this library with files
   compiled with a GNU compiler to produce an executable, this does
   not cause the resulting executable to be covered by the GNU General
   Public License.  This exception does not however invalidate any
   other reasons why the executable file might be covered by the GNU
   General Public License.  */


#ifndef _POSIX_SOURCE
# define _POSIX_SOURCE
#endif
#include "libioP.h"
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <errno.h>
#ifdef __STDC__
#include <stdlib.h>
#endif
#if _LIBC
# include "../wcsmbs/wcsmbsload.h"
#endif
#ifndef errno
extern int errno;
#endif
#ifndef __set_errno
# define __set_errno(Val) errno = (Val)
#endif


#ifdef _LIBC
# define open(Name, Flags, Prot) __open (Name, Flags, Prot)
# define close(FD) __close (FD)
# define lseek(FD, Offset, Whence) __lseek (FD, Offset, Whence)
# define read(FD, Buf, NBytes) __read (FD, Buf, NBytes)
# define write(FD, Buf, NBytes) __write (FD, Buf, NBytes)
#endif

/* An fstream can be in at most one of put mode, get mode, or putback mode.
   Putback mode is a variant of get mode.

   In a filebuf, there is only one current position, instead of two
   separate get and put pointers.  In get mode, the current position
   is that of gptr(); in put mode that of pptr().

   The position in the buffer that corresponds to the position
   in external file system is normally _IO_read_end, except in putback
   mode, when it is _IO_save_end.
   If the field _fb._offset is >= 0, it gives the offset in
   the file as a whole corresponding to eGptr(). (?)

   PUT MODE:
   If a filebuf is in put mode, then all of _IO_read_ptr, _IO_read_end,
   and _IO_read_base are equal to each other.  These are usually equal
   to _IO_buf_base, though not necessarily if we have switched from
   get mode to put mode.  (The reason is to maintain the invariant
   that _IO_read_end corresponds to the external file position.)
   _IO_write_base is non-NULL and usually equal to _IO_base_base.
   We also have _IO_write_end == _IO_buf_end, but only in fully buffered mode.
   The un-flushed character are those between _IO_write_base and _IO_write_ptr.

   GET MODE:
   If a filebuf is in get or putback mode, eback() != egptr().
   In get mode, the unread characters are between gptr() and egptr().
   The OS file position corresponds to that of egptr().

   PUTBACK MODE:
   Putback mode is used to remember "excess" characters that have
   been sputbackc'd in a separate putback buffer.
   In putback mode, the get buffer points to the special putback buffer.
   The unread characters are the characters between gptr() and egptr()
   in the putback buffer, as well as the area between save_gptr()
   and save_egptr(), which point into the original reserve buffer.
   (The pointers save_gptr() and save_egptr() are the values
   of gptr() and egptr() at the time putback mode was entered.)
   The OS position corresponds to that of save_egptr().

   LINE BUFFERED OUTPUT:
   During line buffered output, _IO_write_base==base() && epptr()==base().
   However, ptr() may be anywhere between base() and ebuf().
   This forces a call to filebuf::overflow(int C) on every put.
   If there is more space in the buffer, and C is not a '\n',
   then C is inserted, and pptr() incremented.

   UNBUFFERED STREAMS:
   If a filebuf is unbuffered(), the _shortbuf[1] is used as the buffer.
*/

#define CLOSED_FILEBUF_FLAGS \
  (_IO_IS_FILEBUF+_IO_NO_READS+_IO_NO_WRITES+_IO_TIED_PUT_GET)


void
_IO_new_file_init (fp)
     _IO_FILE *fp;
{
  /* POSIX.1 allows another file handle to be used to change the position
     of our file descriptor.  Hence we actually don't know the actual
     position before we do the first fseek (and until a following fflush). */
  fp->_offset = _IO_pos_BAD;
  fp->_IO_file_flags |= CLOSED_FILEBUF_FLAGS;

  _IO_link_in(fp);
  fp->_fileno = -1;
}

int
_IO_new_file_close_it (fp)
     _IO_FILE *fp;
{
  int write_status, close_status;
  if (!_IO_file_is_open (fp))
    return EOF;

  write_status = _IO_do_flush (fp);

  _IO_unsave_markers(fp);

  close_status = _IO_SYSCLOSE (fp);

  /* Free buffer. */
  if (fp->_mode <= 0)
    {
      _IO_setb (fp, NULL, NULL, 0);
      _IO_setg (fp, NULL, NULL, NULL);
      _IO_setp (fp, NULL, NULL);
    }
  else
    {
      _IO_wsetb (fp, NULL, NULL, 0);
      _IO_wsetg (fp, NULL, NULL, NULL);
      _IO_wsetp (fp, NULL, NULL);
    }

  _IO_un_link (fp);
  fp->_flags = _IO_MAGIC|CLOSED_FILEBUF_FLAGS;
  fp->_fileno = -1;
  fp->_offset = _IO_pos_BAD;

  return close_status ? close_status : write_status;
}

void
_IO_new_file_finish (fp, dummy)
     _IO_FILE *fp;
     int dummy;
{
  if (_IO_file_is_open (fp))
    {
      _IO_do_flush (fp);
      if (!(fp->_flags & _IO_DELETE_DONT_CLOSE))
	_IO_SYSCLOSE (fp);
    }
  _IO_default_finish (fp, 0);
}

#if defined __GNUC__ && __GNUC__ >= 2
__inline__
#endif
_IO_FILE *
_IO_file_open (fp, filename, posix_mode, prot, read_write, is32not64)
     _IO_FILE *fp;
     const char *filename;
     int posix_mode;
     int prot;
     int read_write;
     int is32not64;
{
  int fdesc;
#ifdef _G_OPEN64
  fdesc = (is32not64
	   ? open (filename, posix_mode, prot)
	   : _G_OPEN64 (filename, posix_mode, prot));
#else
  fdesc = open (filename, posix_mode, prot);
#endif
  if (fdesc < 0)
    return NULL;
  fp->_fileno = fdesc;
  _IO_mask_flags (fp, read_write,_IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
  if (read_write & _IO_IS_APPENDING)
    if (_IO_SEEKOFF (fp, (_IO_off64_t)0, _IO_seek_end, _IOS_INPUT|_IOS_OUTPUT)
	== _IO_pos_BAD && errno != ESPIPE)
      return NULL;
  _IO_link_in (fp);
  return fp;
}

_IO_FILE *
_IO_new_file_fopen (fp, filename, mode, is32not64)
     _IO_FILE *fp;
     const char *filename;
     const char *mode;
     int is32not64;
{
  int oflags = 0, omode;
  int read_write;
  int oprot = 0666;
  int i;
  _IO_FILE *result;
#if _LIBC
  const char *cs;
#endif

  if (_IO_file_is_open (fp))
    return 0;
  switch (*mode)
    {
    case 'r':
      omode = O_RDONLY;
      read_write = _IO_NO_WRITES;
      break;
    case 'w':
      omode = O_WRONLY;
      oflags = O_CREAT|O_TRUNC;
      read_write = _IO_NO_READS;
      break;
    case 'a':
      omode = O_WRONLY;
      oflags = O_CREAT|O_APPEND;
      read_write = _IO_NO_READS|_IO_IS_APPENDING;
      break;
    default:
      __set_errno (EINVAL);
      return NULL;
    }
  for (i = 1; i < 4; ++i)
    {
      switch (*++mode)
	{
	case '\0':
	  break;
	case '+':
	  omode = O_RDWR;
	  read_write &= _IO_IS_APPENDING;
	  continue;
	case 'x':
	  oflags |= O_EXCL;
	  continue;
	case 'b':
	default:
	  /* Ignore.  */
	  continue;
	}
      break;
    }

  result = _IO_file_open (fp, filename, omode|oflags, oprot, read_write,
			  is32not64);


#if _LIBC
  /* Test whether the mode string specifies the conversion.  */
  cs = strstr (mode, ",ccs=");
  if (cs != NULL)
    {
      /* Yep.  Load the appropriate conversions and set the orientation
	 to wide.  */
	struct gconv_fcts fcts;
	struct _IO_codecvt *cc = &fp->_wide_data->_codecvt;

	if (__wcsmbs_named_conv (&fcts, cs + 5) != 0)
	  {
	    /* Something went wrong, we cannot load the conversion modules.
	       This means we cannot proceed since the user explicitly asked
	       for these.  */
	    _IO_new_fclose (result);
	    return NULL;
	  }

	/* The functions are always the same.  */
	*cc = __libio_codecvt;

	cc->__cd_in.__cd.__nsteps = 1; /* Only one step allowed.  */
	cc->__cd_in.__cd.__steps = fcts.towc;

	cc->__cd_in.__cd.__data[0].__invocation_counter = 0;
	cc->__cd_in.__cd.__data[0].__internal_use = 1;
	cc->__cd_in.__cd.__data[0].__is_last = 1;
	cc->__cd_in.__cd.__data[0].__statep = &result->_wide_data->_IO_state;

	cc->__cd_out.__cd.__nsteps = 1; /* Only one step allowed.  */
	cc->__cd_out.__cd.__steps = fcts.tomb;

	cc->__cd_out.__cd.__data[0].__invocation_counter = 0;
	cc->__cd_out.__cd.__data[0].__internal_use = 1;
	cc->__cd_out.__cd.__data[0].__is_last = 1;
	cc->__cd_out.__cd.__data[0].__statep = &result->_wide_data->_IO_state;

	/* Set the mode now.  */
	result->_mode = 1;
    }
#endif	/* GNU libc */

  return result;
}

_IO_FILE *
_IO_new_file_attach (fp, fd)
     _IO_FILE *fp;
     int fd;
{
  if (_IO_file_is_open (fp))
    return NULL;
  fp->_fileno = fd;
  fp->_flags &= ~(_IO_NO_READS+_IO_NO_WRITES);
  fp->_flags |= _IO_DELETE_DONT_CLOSE;
  /* Get the current position of the file. */
  /* We have to do that since that may be junk. */
  fp->_offset = _IO_pos_BAD;
  if (_IO_SEEKOFF (fp, (_IO_off64_t)0, _IO_seek_cur, _IOS_INPUT|_IOS_OUTPUT)
      == _IO_pos_BAD && errno != ESPIPE)
    return NULL;
  return fp;
}

_IO_FILE *
_IO_new_file_setbuf (fp, p, len)
     _IO_FILE *fp;
     char *p;
     _IO_ssize_t len;
{
  if (_IO_default_setbuf (fp, p, len) == NULL)
    return NULL;

  fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end
    = fp->_IO_buf_base;
  _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);

  return fp;
}

static int new_do_write __P ((_IO_FILE *, const char *, _IO_size_t));

/* Write TO_DO bytes from DATA to FP.
   Then mark FP as having empty buffers. */

int
_IO_new_do_write (fp, data, to_do)
     _IO_FILE *fp;
     const char *data;
     _IO_size_t to_do;
{
  return (to_do == 0 || new_do_write (fp, data, to_do) == to_do)
  	 ? 0 : EOF;
}

static
int
new_do_write (fp, data, to_do)
     _IO_FILE *fp;
     const char *data;
     _IO_size_t to_do;
{
  _IO_size_t count;
  if (fp->_flags & _IO_IS_APPENDING)
    /* On a system without a proper O_APPEND implementation,
       you would need to sys_seek(0, SEEK_END) here, but is
       is not needed nor desirable for Unix- or Posix-like systems.
       Instead, just indicate that offset (before and after) is
       unpredictable. */
    fp->_offset = _IO_pos_BAD;
  else if (fp->_IO_read_end != fp->_IO_write_base)
    {
      _IO_off64_t new_pos
	= _IO_SYSSEEK (fp, fp->_IO_write_base - fp->_IO_read_end, 1);
      if (new_pos == _IO_pos_BAD)
	return 0;
      fp->_offset = new_pos;
    }
  count = _IO_SYSWRITE (fp, data, to_do);
  if (fp->_cur_column && count)
    fp->_cur_column = _IO_adjust_column (fp->_cur_column - 1, data, count) + 1;
  _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
  fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_buf_base;
  fp->_IO_write_end = (fp->_mode < 0
		       && (fp->_flags & (_IO_LINE_BUF+_IO_UNBUFFERED))
		       ? fp->_IO_buf_base : fp->_IO_buf_end);
  return count;
}

int
_IO_new_file_underflow (fp)
     _IO_FILE *fp;
{
  _IO_ssize_t count;
#if 0
  /* SysV does not make this test; take it out for compatibility */
  if (fp->_flags & _IO_EOF_SEEN)
    return (EOF);
#endif

  if (fp->_flags & _IO_NO_READS)
    {
      fp->_flags |= _IO_ERR_SEEN;
      __set_errno (EBADF);
      return EOF;
    }
  if (fp->_IO_read_ptr < fp->_IO_read_end)
    return *(unsigned char *) fp->_IO_read_ptr;

  if (fp->_IO_buf_base == NULL)
    {
      /* Maybe we already have a push back pointer.  */
      if (fp->_IO_save_base != NULL)
	{
	  free (fp->_IO_save_base);
	  fp->_flags &= ~_IO_IN_BACKUP;
	}
      _IO_doallocbuf (fp);
    }

  /* Flush all line buffered files before reading. */
  /* FIXME This can/should be moved to genops ?? */
  if (fp->_flags & (_IO_LINE_BUF|_IO_UNBUFFERED))
    _IO_flush_all_linebuffered ();

  _IO_switch_to_get_mode (fp);

  /* This is very tricky. We have to adjust those
     pointers before we call _IO_SYSREAD () since
     we may longjump () out while waiting for
     input. Those pointers may be screwed up. H.J. */
  fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_buf_base;
  fp->_IO_read_end = fp->_IO_buf_base;
  fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end
    = fp->_IO_buf_base;

  count = _IO_SYSREAD (fp, fp->_IO_buf_base,
		       fp->_IO_buf_end - fp->_IO_buf_base);
  if (count <= 0)
    {
      if (count == 0)
	fp->_flags |= _IO_EOF_SEEN;
      else
	fp->_flags |= _IO_ERR_SEEN, count = 0;
  }
  fp->_IO_read_end += count;
  if (count == 0)
    return EOF;
  if (fp->_offset != _IO_pos_BAD)
    _IO_pos_adjust (fp->_offset, count);
  return *(unsigned char *) fp->_IO_read_ptr;
}

int
_IO_new_file_overflow (f, ch)
      _IO_FILE *f;
      int ch;
{
  if (f->_flags & _IO_NO_WRITES) /* SET ERROR */
    {
      f->_flags |= _IO_ERR_SEEN;
      __set_errno (EBADF);
      return EOF;
    }
  /* If currently reading or no buffer allocated. */
  if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0 || f->_IO_write_base == 0)
    {
      /* Allocate a buffer if needed. */
      if (f->_IO_write_base == 0)
	{
	  _IO_doallocbuf (f);
	  _IO_setg (f, f->_IO_buf_base, f->_IO_buf_base, f->_IO_buf_base);
	}
      /* Otherwise must be currently reading.
	 If _IO_read_ptr (and hence also _IO_read_end) is at the buffer end,
	 logically slide the buffer forwards one block (by setting the
	 read pointers to all point at the beginning of the block).  This
	 makes room for subsequent output.
	 Otherwise, set the read pointers to _IO_read_end (leaving that
	 alone, so it can continue to correspond to the external position). */
      if (f->_IO_read_ptr == f->_IO_buf_end)
	f->_IO_read_end = f->_IO_read_ptr = f->_IO_buf_base;
      f->_IO_write_ptr = f->_IO_read_ptr;
      f->_IO_write_base = f->_IO_write_ptr;
      f->_IO_write_end = f->_IO_buf_end;
      f->_IO_read_base = f->_IO_read_ptr = f->_IO_read_end;

      f->_flags |= _IO_CURRENTLY_PUTTING;
      if (f->_mode < 0 && f->_flags & (_IO_LINE_BUF+_IO_UNBUFFERED))
	f->_IO_write_end = f->_IO_write_ptr;
    }
  if (ch == EOF)
    return _IO_new_do_write(f, f->_IO_write_base,
			    f->_IO_write_ptr - f->_IO_write_base);
  if (f->_IO_write_ptr == f->_IO_buf_end ) /* Buffer is really full */
    if (_IO_do_flush (f) == EOF)
      return EOF;
  *f->_IO_write_ptr++ = ch;
  if ((f->_flags & _IO_UNBUFFERED)
      || ((f->_flags & _IO_LINE_BUF) && ch == '\n'))
    if (_IO_new_do_write(f, f->_IO_write_base,
			 f->_IO_write_ptr - f->_IO_write_base) == EOF)
      return EOF;
  return (unsigned char) ch;
}

int
_IO_new_file_sync (fp)
     _IO_FILE *fp;
{
  _IO_ssize_t delta;
  int retval = 0;

  /*    char* ptr = cur_ptr(); */
  if (fp->_IO_write_ptr > fp->_IO_write_base)
    if (_IO_do_flush(fp)) return EOF;
  delta = fp->_IO_read_ptr - fp->_IO_read_end;
  if (delta != 0)
    {
#ifdef TODO
      if (_IO_in_backup (fp))
	delta -= eGptr () - Gbase ();
#endif
      _IO_off64_t new_pos = _IO_SYSSEEK (fp, delta, 1);
      if (new_pos != (_IO_off64_t) EOF)
	fp->_IO_read_end = fp->_IO_read_ptr;
#ifdef ESPIPE
      else if (errno == ESPIPE)
	; /* Ignore error from unseekable devices. */
#endif
      else
	retval = EOF;
    }
  if (retval != EOF)
    fp->_offset = _IO_pos_BAD;
  /* FIXME: Cleanup - can this be shared? */
  /*    setg(base(), ptr, ptr); */
  return retval;
}

_IO_off64_t
_IO_new_file_seekoff (fp, offset, dir, mode)
     _IO_FILE *fp;
     _IO_off64_t offset;
     int dir;
     int mode;
{
  _IO_off64_t result;
  _IO_off64_t delta, new_offset;
  long count;
  /* POSIX.1 8.2.3.7 says that after a call the fflush() the file
     offset of the underlying file must be exact.  */
  int must_be_exact = (fp->_IO_read_base == fp->_IO_read_end
		       && fp->_IO_write_base == fp->_IO_write_ptr);

  if (mode == 0)
    dir = _IO_seek_cur, offset = 0; /* Don't move any pointers. */

  /* Flush unwritten characters.
     (This may do an unneeded write if we seek within the buffer.
     But to be able to switch to reading, we would need to set
     egptr to ptr.  That can't be done in the current design,
     which assumes file_ptr() is eGptr.  Anyway, since we probably
     end up flushing when we close(), it doesn't make much difference.)
     FIXME: simulate mem-papped files. */

  if (fp->_IO_write_ptr > fp->_IO_write_base || _IO_in_put_mode (fp))
    if (_IO_switch_to_get_mode (fp))
      return EOF;

  if (fp->_IO_buf_base == NULL)
    {
      /* It could be that we already have a pushback buffer.  */
      if (fp->_IO_read_base != NULL)
	{
	  free (fp->_IO_read_base);
	  fp->_flags &= ~_IO_IN_BACKUP;
	}
      _IO_doallocbuf (fp);
      _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
      _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
    }

  switch (dir)
    {
    case _IO_seek_cur:
      /* Adjust for read-ahead (bytes is buffer). */
      offset -= fp->_IO_read_end - fp->_IO_read_ptr;
      if (fp->_offset == _IO_pos_BAD)
	goto dumb;
      /* Make offset absolute, assuming current pointer is file_ptr(). */
      offset += fp->_offset;

      dir = _IO_seek_set;
      break;
    case _IO_seek_set:
      break;
    case _IO_seek_end:
      {
	struct _G_stat64 st;
	if (_IO_SYSSTAT (fp, &st) == 0 && S_ISREG (st.st_mode))
	  {
	    offset += st.st_size;
	    dir = _IO_seek_set;
	  }
	else
	  goto dumb;
      }
    }
  /* At this point, dir==_IO_seek_set. */

  /* If we are only interested in the current position we've found it now.  */
  if (mode == 0)
    return offset;

  /* If destination is within current buffer, optimize: */
  if (fp->_offset != _IO_pos_BAD && fp->_IO_read_base != NULL
      && !_IO_in_backup (fp))
    {
      /* Offset relative to start of main get area. */
      _IO_off64_t rel_offset = (offset - fp->_offset
				+ (fp->_IO_read_end - fp->_IO_read_base));
      if (rel_offset >= 0)
	{
#if 0
	  if (_IO_in_backup (fp))
	    _IO_switch_to_main_get_area (fp);
#endif
	  if (rel_offset <= fp->_IO_read_end - fp->_IO_read_base)
	    {
	      _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base + rel_offset,
			fp->_IO_read_end);
	      _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
	      {
		_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
		goto resync;
	      }
	    }
#ifdef TODO
	    /* If we have streammarkers, seek forward by reading ahead. */
	    if (_IO_have_markers (fp))
	      {
		int to_skip = rel_offset
		  - (fp->_IO_read_ptr - fp->_IO_read_base);
		if (ignore (to_skip) != to_skip)
		  goto dumb;
		_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
		goto resync;
	      }
#endif
	}
#ifdef TODO
      if (rel_offset < 0 && rel_offset >= Bbase () - Bptr ())
	{
	  if (!_IO_in_backup (fp))
	    _IO_switch_to_backup_area (fp);
	  gbump (fp->_IO_read_end + rel_offset - fp->_IO_read_ptr);
	  _IO_mask_flags (fp, 0, _IO_EOF_SEEN);
	  goto resync;
	}
#endif
    }

#ifdef TODO
  _IO_unsave_markers (fp);
#endif

  if (fp->_flags & _IO_NO_READS)
    goto dumb;

  /* Try to seek to a block boundary, to improve kernel page management. */
  new_offset = offset & ~(fp->_IO_buf_end - fp->_IO_buf_base - 1);
  delta = offset - new_offset;
  if (delta > fp->_IO_buf_end - fp->_IO_buf_base)
    {
      new_offset = offset;
      delta = 0;
    }
  result = _IO_SYSSEEK (fp, new_offset, 0);
  if (result < 0)
    return EOF;
  if (delta == 0)
    count = 0;
  else
    {
      count = _IO_SYSREAD (fp, fp->_IO_buf_base,
			   (must_be_exact
			    ? delta : fp->_IO_buf_end - fp->_IO_buf_base));
      if (count < delta)
	{
	  /* We weren't allowed to read, but try to seek the remainder. */
	  offset = count == EOF ? delta : delta-count;
	  dir = _IO_seek_cur;
	  goto dumb;
	}
    }
  _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base + delta,
	    fp->_IO_buf_base + count);
  _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
  fp->_offset = result + count;
  _IO_mask_flags (fp, 0, _IO_EOF_SEEN);
  return offset;
 dumb:

  _IO_unsave_markers (fp);
  result = _IO_SYSSEEK (fp, offset, dir);
  if (result != EOF)
    {
      _IO_mask_flags (fp, 0, _IO_EOF_SEEN);
      fp->_offset = result;
      _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
      _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);
    }
  return result;

resync:
  /* We need to do it since it is possible that the file offset in
     the kernel may be changed behind our back. It may happen when
     we fopen a file and then do a fork. One process may access the
     the file and the kernel file offset will be changed. */
  if (fp->_offset >= 0)
    _IO_SYSSEEK (fp, fp->_offset, 0);

  return offset;
}

_IO_ssize_t
_IO_file_read (fp, buf, size)
     _IO_FILE *fp;
     void *buf;
     _IO_ssize_t size;
{
  return read (fp->_fileno, buf, size);
}

_IO_off64_t
_IO_file_seek (fp, offset, dir)
     _IO_FILE *fp;
     _IO_off64_t offset;
     int dir;
{
#ifdef _G_LSEEK64
  return _G_LSEEK64 (fp->_fileno, offset, dir);
#else
  return lseek (fp->_fileno, offset, dir);
#endif
}

int
_IO_file_stat (fp, st)
     _IO_FILE *fp;
     void *st;
{
#ifdef _G_FSTAT64
  return _G_FSTAT64 (fp->_fileno, (struct _G_stat64 *) st);
#else
  return fstat (fp->_fileno, (struct _G_stat64 *) st);
#endif
}

int
_IO_file_close (fp)
     _IO_FILE *fp;
{
  return close (fp->_fileno);
}

_IO_ssize_t
_IO_new_file_write (f, data, n)
     _IO_FILE *f;
     const void *data;
     _IO_ssize_t n;
{
  _IO_ssize_t to_do = n;
  while (to_do > 0)
    {
      _IO_ssize_t count = write (f->_fileno, data, to_do);
      if (count < 0)
	{
	  f->_flags |= _IO_ERR_SEEN;
	  break;
        }
      to_do -= count;
      data = (void *) ((char *) data + count);
    }
  n -= to_do;
  if (f->_offset >= 0)
    f->_offset += n;
  return n;
}

_IO_size_t
_IO_new_file_xsputn (f, data, n)
     _IO_FILE *f;
     const void *data;
     _IO_size_t n;
{
  register const char *s = (const char *) data;
  _IO_size_t to_do = n;
  int must_flush = 0;
  _IO_size_t count;

  if (n <= 0)
    return 0;
  /* This is an optimized implementation.
     If the amount to be written straddles a block boundary
     (or the filebuf is unbuffered), use sys_write directly. */

  /* First figure out how much space is available in the buffer. */
  count = f->_IO_write_end - f->_IO_write_ptr; /* Space available. */
  if ((f->_flags & _IO_LINE_BUF) && (f->_flags & _IO_CURRENTLY_PUTTING))
    {
      count = f->_IO_buf_end - f->_IO_write_ptr;
      if (count >= n)
	{
	  register const char *p;
	  for (p = s + n; p > s; )
	    {
	      if (*--p == '\n')
		{
		  count = p - s + 1;
		  must_flush = 1;
		  break;
		}
	    }
	}
    }
  /* Then fill the buffer. */
  if (count > 0)
    {
      if (count > to_do)
	count = to_do;
      if (count > 20)
	{
#ifdef _LIBC
	  f->_IO_write_ptr = __mempcpy (f->_IO_write_ptr, s, count);
#else
	  memcpy (f->_IO_write_ptr, s, count);
	  f->_IO_write_ptr += count;
#endif
	  s += count;
	}
      else
	{
	  register char *p = f->_IO_write_ptr;
	  register int i = (int) count;
	  while (--i >= 0)
	    *p++ = *s++;
	  f->_IO_write_ptr = p;
	}
      to_do -= count;
    }
  if (to_do + must_flush > 0)
    {
      _IO_size_t block_size, do_write;
      /* Next flush the (full) buffer. */
      if (_IO_OVERFLOW (f, EOF) == EOF)
	return n - to_do;

      /* Try to maintain alignment: write a whole number of blocks.
	 dont_write is what gets left over. */
      block_size = f->_IO_buf_end - f->_IO_buf_base;
      do_write = to_do - (block_size >= 128 ? to_do % block_size : 0);

      if (do_write)
        {
	  count = new_do_write (f, s, do_write);
	  to_do -= count;
	  if (count < do_write)
	    return n - to_do;
        }

      /* Now write out the remainder.  Normally, this will fit in the
	 buffer, but it's somewhat messier for line-buffered files,
	 so we let _IO_default_xsputn handle the general case. */
      if (to_do)
	to_do -= _IO_default_xsputn (f, s+do_write, to_do);
    }
  return n - to_do;
}

_IO_size_t
_IO_file_xsgetn (fp, data, n)
     _IO_FILE *fp;
     void *data;
     _IO_size_t n;
{
  register _IO_size_t want, have;
  register _IO_ssize_t count;
  register char *s = data;

  want = n;

  if (fp->_IO_buf_base == NULL)
    {
      /* Maybe we already have a push back pointer.  */
      if (fp->_IO_save_base != NULL)
	{
	  free (fp->_IO_save_base);
	  fp->_flags &= ~_IO_IN_BACKUP;
	}
      _IO_doallocbuf (fp);
    }

  while (want > 0)
    {
      have = fp->_IO_read_end - fp->_IO_read_ptr;
      if (want <= have)
	{
	  memcpy (s, fp->_IO_read_ptr, want);
	  fp->_IO_read_ptr += want;
	  want = 0;
	}
      else
	{
	  if (have > 0)
	    {
#ifdef _LIBC
	      s = __mempcpy (s, fp->_IO_read_ptr, have);
#else
	      memcpy (s, fp->_IO_read_ptr, have);
	      s += have;
#endif
	      want -= have;
	      fp->_IO_read_ptr += have;
	    }

	  /* Check for backup and repeat */
	  if (_IO_in_backup (fp))
	    {
	      _IO_switch_to_main_get_area (fp);
	      continue;
	    }

	  /* If we now want less than a buffer, underflow and repeat
	     the copy.  Otherwise, _IO_SYSREAD directly to
	     the user buffer. */
	  if (fp->_IO_buf_base && want < fp->_IO_buf_end - fp->_IO_buf_base)
	    {
	      if (__underflow (fp) == EOF)
		break;

	      continue;
	    }

	  /* These must be set before the sysread as we might longjmp out
	     waiting for input. */
	  _IO_setg (fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base);
	  _IO_setp (fp, fp->_IO_buf_base, fp->_IO_buf_base);

	  /* Try to maintain alignment: read a whole number of blocks.  */
	  count = want;
	  if (fp->_IO_buf_base)
	    {
	      _IO_size_t block_size = fp->_IO_buf_end - fp->_IO_buf_base;
	      if (block_size >= 128)
		count -= want % block_size;
	    }

	  count = _IO_SYSREAD (fp, s, count);
	  if (count <= 0)
	    {
	      if (count == 0)
		fp->_flags |= _IO_EOF_SEEN;
	      else
		fp->_flags |= _IO_ERR_SEEN;

	      break;
	    }

	  s += count;
	  want -= count;
	  if (fp->_offset != _IO_pos_BAD)
	    _IO_pos_adjust (fp->_offset, count);
	}
    }

  return n - want;
}

struct _IO_jump_t _IO_file_jumps =
{
  JUMP_INIT_DUMMY,
  JUMP_INIT(finish, _IO_new_file_finish),
  JUMP_INIT(overflow, _IO_new_file_overflow),
  JUMP_INIT(underflow, _IO_new_file_underflow),
  JUMP_INIT(uflow, _IO_default_uflow),
  JUMP_INIT(pbackfail, _IO_default_pbackfail),
  JUMP_INIT(xsputn, _IO_new_file_xsputn),
  JUMP_INIT(xsgetn, _IO_file_xsgetn),
  JUMP_INIT(seekoff, _IO_new_file_seekoff),
  JUMP_INIT(seekpos, _IO_default_seekpos),
  JUMP_INIT(setbuf, _IO_new_file_setbuf),
  JUMP_INIT(sync, _IO_new_file_sync),
  JUMP_INIT(doallocate, _IO_file_doallocate),
  JUMP_INIT(read, _IO_file_read),
  JUMP_INIT(write, _IO_new_file_write),
  JUMP_INIT(seek, _IO_file_seek),
  JUMP_INIT(close, _IO_file_close),
  JUMP_INIT(stat, _IO_file_stat),
  JUMP_INIT(showmanyc, _IO_default_showmanyc),
  JUMP_INIT(imbue, _IO_default_imbue)
};


#if defined PIC && DO_VERSIONING
default_symbol_version (_IO_new_do_write, _IO_do_write, GLIBC_2.1);
default_symbol_version (_IO_new_file_attach, _IO_file_attach, GLIBC_2.1);
default_symbol_version (_IO_new_file_close_it, _IO_file_close_it, GLIBC_2.1);
default_symbol_version (_IO_new_file_finish, _IO_file_finish, GLIBC_2.1);
default_symbol_version (_IO_new_file_fopen, _IO_file_fopen, GLIBC_2.1);
default_symbol_version (_IO_new_file_init, _IO_file_init, GLIBC_2.1);
default_symbol_version (_IO_new_file_setbuf, _IO_file_setbuf, GLIBC_2.1);
default_symbol_version (_IO_new_file_sync, _IO_file_sync, GLIBC_2.1);
default_symbol_version (_IO_new_file_overflow, _IO_file_overflow, GLIBC_2.1);
default_symbol_version (_IO_new_file_seekoff, _IO_file_seekoff, GLIBC_2.1);
default_symbol_version (_IO_new_file_underflow, _IO_file_underflow, GLIBC_2.1);
default_symbol_version (_IO_new_file_write, _IO_file_write, GLIBC_2.1);
default_symbol_version (_IO_new_file_xsputn, _IO_file_xsputn, GLIBC_2.1);
#else
# ifdef strong_alias
strong_alias (_IO_new_do_write, _IO_do_write);
strong_alias (_IO_new_file_attach, _IO_file_attach);
strong_alias (_IO_new_file_close_it, _IO_file_close_it);
strong_alias (_IO_new_file_finish, _IO_file_finish);
strong_alias (_IO_new_file_fopen, _IO_file_fopen);
strong_alias (_IO_new_file_init, _IO_file_init);
strong_alias (_IO_new_file_setbuf, _IO_file_setbuf);
strong_alias (_IO_new_file_sync, _IO_file_sync);
strong_alias (_IO_new_file_overflow, _IO_file_overflow);
strong_alias (_IO_new_file_seekoff, _IO_file_seekoff);
strong_alias (_IO_new_file_underflow, _IO_file_underflow);
strong_alias (_IO_new_file_write, _IO_file_write);
strong_alias (_IO_new_file_xsputn, _IO_file_xsputn);
# endif
#endif