1 /* Linux implementation of preadv2 (LFS version).
2 Copyright (C) 2017-2022 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 <https://www.gnu.org/licenses/>. */
18
19 #include <sys/uio.h>
20 #include <sysdep-cancel.h>
21
22 ssize_t
preadv64v2(int fd,const struct iovec * vector,int count,off64_t offset,int flags)23 preadv64v2 (int fd, const struct iovec *vector, int count, off64_t offset,
24 int flags)
25 {
26 ssize_t result = SYSCALL_CANCEL (preadv2, fd, vector, count,
27 LO_HI_LONG (offset), flags);
28 if (result >= 0 || errno != ENOSYS)
29 return result;
30
31 /* Trying to emulate the preadv2 syscall flags is troublesome:
32
33 * We can not temporary change the file state of the O_DSYNC and O_SYNC
34 flags to emulate RWF_{D}SYNC (attempts to change the state of using
35 fcntl are silently ignored).
36
37 * IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal
38 semantic not provided by any other flag (O_NONBLOCK for instance). */
39
40 if (flags != 0)
41 {
42 __set_errno (ENOTSUP);
43 return -1;
44 }
45
46 if (offset == -1)
47 return __readv (fd, vector, count);
48 else
49 return preadv64 (fd, vector, count, offset);
50 }
51
52 #ifdef __OFF_T_MATCHES_OFF64_T
53 strong_alias (preadv64v2, preadv2)
54 #endif
55