1/* Copyright (C) 1993-2020 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>.
17
18 As a special exception, if you link the code in this file with
19 files compiled with a GNU compiler to produce an executable,
20 that does not cause the resulting executable to be covered by
21 the GNU Lesser General Public License. This exception does not
22 however invalidate any other reasons why the executable file
23 might be covered by the GNU Lesser General Public License.
24 This exception applies to code released by its copyright holders
25 in files containing the exception. */
26
27#include <stdlib.h>
28#include <libioP.h>
29#include <errno.h>
30
31off64_t
32_IO_seekoff_unlocked (FILE *fp, off64_t offset, int dir, int mode)
33{
34 if (dir != _IO_seek_cur && dir != _IO_seek_set && dir != _IO_seek_end)
35 {
36 __set_errno (EINVAL);
37 return EOF;
38 }
39
40 /* If we have a backup buffer, get rid of it, since the __seekoff
41 callback may not know to do the right thing about it.
42 This may be over-kill, but it'll do for now. TODO */
43 if (mode != 0 && ((_IO_fwide (fp, 0) < 0 && _IO_have_backup (fp))
44 || (_IO_fwide (fp, 0) > 0 && _IO_have_wbackup (fp))))
45 {
46 if (dir == _IO_seek_cur && _IO_in_backup (fp))
47 {
48 if (_IO_vtable_offset (fp) != 0 || fp->_mode <= 0)
49 offset -= fp->_IO_read_end - fp->_IO_read_ptr;
50 else
51 abort ();
52 }
53 if (_IO_fwide (fp, 0) < 0)
54 _IO_free_backup_area (fp);
55 else
56 _IO_free_wbackup_area (fp);
57 }
58
59 return _IO_SEEKOFF (fp, offset, dir, mode);
60}
61
62
63off64_t
64_IO_seekoff (FILE *fp, off64_t offset, int dir, int mode)
65{
66 off64_t retval;
67
68 _IO_acquire_lock (fp);
69 retval = _IO_seekoff_unlocked (fp, offset, dir, mode);
70 _IO_release_lock (fp);
71 return retval;
72}
73