1/* Linux implementation of preadv2 (LFS version).
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#if !defined(__NR_preadv64v2) && defined(__NR_preadv2)
23# define __NR_preadv64v2 __NR_preadv2
24#endif
25
26ssize_t
27preadv64v2 (int fd, const struct iovec *vector, int count, off64_t offset,
28 int flags)
29{
30#ifdef __NR_preadv64v2
31 ssize_t result = SYSCALL_CANCEL (preadv64v2, fd, vector, count,
32 LO_HI_LONG (offset), flags);
33 if (result >= 0 || errno != ENOSYS)
34 return result;
35#endif
36 /* Trying to emulate the preadv2 syscall flags is troublesome:
37
38 * We can not temporary change the file state of the O_DSYNC and O_SYNC
39 flags to emulate RWF_{D}SYNC (attempts to change the state of using
40 fcntl are silently ignored).
41
42 * IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal
43 semantic not provided by any other flag (O_NONBLOCK for instance). */
44
45 if (flags != 0)
46 {
47 __set_errno (ENOTSUP);
48 return -1;
49 }
50
51 if (offset == -1)
52 return __readv (fd, vector, count);
53 else
54 return preadv64 (fd, vector, count, offset);
55}
56
57#ifdef __OFF_T_MATCHES_OFF64_T
58strong_alias (preadv64v2, preadv2)
59#endif
60