1/* Linux implementation of preadv2.
2 Copyright (C) 2017-2019 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#include <sys/uio.h>
20#include <sysdep-cancel.h>
21
22#ifndef __OFF_T_MATCHES_OFF64_T
23
24# if !defined (__NR_preadv2) && defined (__NR_pread64v2)
25# define __NR_preadv2 __NR_pread64v2
26# endif
27
28ssize_t
29preadv2 (int fd, const struct iovec *vector, int count, off_t offset,
30 int flags)
31{
32# ifdef __NR_preadv2
33 ssize_t result = SYSCALL_CANCEL (preadv2, fd, vector, count,
34 LO_HI_LONG (offset), flags);
35 if (result >= 0 || errno != ENOSYS)
36 return result;
37# endif
38 /* Trying to emulate the preadv2 syscall flags is troublesome:
39
40 * We can not temporary change the file state of the O_DSYNC and O_SYNC
41 flags to emulate RWF_{D}SYNC (attempts to change the state of using
42 fcntl are silently ignored).
43
44 * IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal
45 semantic not provided by any other flag (O_NONBLOCK for instance). */
46
47 if (flags != 0)
48 {
49 __set_errno (ENOTSUP);
50 return -1;
51 }
52 if (offset == -1)
53 return __readv (fd, vector, count);
54 else
55 return preadv (fd, vector, count, offset);
56}
57
58#endif
59