59 lines
1.8 KiB
C
59 lines
1.8 KiB
C
/* Linux implementation of preadv2.
|
|
Copyright (C) 2017-2018 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <sys/uio.h>
|
|
#include <sysdep-cancel.h>
|
|
|
|
#ifndef __OFF_T_MATCHES_OFF64_T
|
|
|
|
# if !defined (__NR_preadv2) && defined (__NR_pread64v2)
|
|
# define __NR_preadv2 __NR_pread64v2
|
|
# endif
|
|
|
|
ssize_t
|
|
preadv2 (int fd, const struct iovec *vector, int count, off_t offset,
|
|
int flags)
|
|
{
|
|
# ifdef __NR_preadv2
|
|
ssize_t result = SYSCALL_CANCEL (preadv2, fd, vector, count,
|
|
LO_HI_LONG (offset), flags);
|
|
if (result >= 0)
|
|
return result;
|
|
# endif
|
|
/* Trying to emulate the preadv2 syscall flags is troublesome:
|
|
|
|
* We can not temporary change the file state of the O_DSYNC and O_SYNC
|
|
flags to emulate RWF_{D}SYNC (attempts to change the state of using
|
|
fcntl are silently ignored).
|
|
|
|
* IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal
|
|
semantic not provided by any other flag (O_NONBLOCK for instance). */
|
|
|
|
if (flags != 0)
|
|
{
|
|
__set_errno (ENOTSUP);
|
|
return -1;
|
|
}
|
|
if (offset == -1)
|
|
return __readv (fd, vector, count);
|
|
else
|
|
return preadv (fd, vector, count, offset);
|
|
}
|
|
|
|
#endif
|