glibc/sysdeps/unix/sysv/linux/preadv64.c
Adhemerval Zanella c79a72aa5c posix: Fix and simplify default p{read,write}v implementation
Currently all architectures but microblaze use wire-up syscall for
p{readv,write}v.  Microblaze still uses the syscall emulation using
sysdep/posix/p{readv,writev}.c and it was reported in some ocasions
[1] [2] that it might have some issues with some linux specific
usage (mainly with O_DIRECT and the alignment requirement).

Although it is not an issue for virtually all the system, this
patch refactors the sysdeps/posix p{read,write}v syscall to avoid
such issue (by using posix_memalign on the buffer used on
p{read,write} call) and by refactoring it common files to avoid
the need check on defines to correct set the alias and internal
symbols.

Checked on microblaze-linux-gnu check with run-built-tests=no and
by using the sysdeps/posix implementation on x86_64-linux-gnu (just
for sanity test where it shown no regression).

	* sysdeps/posix/preadv.c: Use sysdeps/posix/preadv_common.c.
	* sysdeps/posix/preadv64.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv64.c: Likewise.
	* sysdeps/posix/pwritev.c: Use sysdeps/posix/pwritev_common.c.
	* sysdeps/posix/pwritev64.c: Likewise.
	* sysdeps/unix/sysv/linux/pwritev.c: Likewise.
	* sysdeps/unix/sysv/linux/pwritev64.c: Likewise.
	* sysdeps/posix/preadv_common.c: New file.
	* sysdeps/posix/pwritev_common.c: Likewise.

[1] http://www.mail-archive.com/qemu-devel@nongnu.org/msg25282.html
[2] https://bugzilla.redhat.com/show_bug.cgi?id=563103#c8
2017-05-15 16:33:45 -03:00

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C

/* Copyright (C) 2016-2017 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>
#ifdef __ASSUME_PREADV
# ifndef __NR_preadv64
# define __NR_preadv64 __NR_preadv
# endif
ssize_t
preadv64 (int fd, const struct iovec *vector, int count, off64_t offset)
{
return SYSCALL_CANCEL (preadv64, fd, vector, count, LO_HI_LONG (offset));
}
#else
static ssize_t __atomic_preadv64_replacement (int, const struct iovec *,
int, off64_t) internal_function;
ssize_t
preadv64 (int fd, const struct iovec *vector, int count, off64_t offset)
{
#ifdef __NR_preadv64
ssize_t result = SYSCALL_CANCEL (preadv64, fd, vector, count,
LO_HI_LONG (offset));
if (result >= 0 || errno != ENOSYS)
return result;
#endif
return __atomic_preadv64_replacement (fd, vector, count, offset);
}
# define PREADV static internal_function __atomic_preadv64_replacement
# define PREAD __pread64
# define OFF_T off64_t
# include <sysdeps/posix/preadv_common.c>
#endif
#ifdef __OFF_T_MATCHES_OFF64_T
strong_alias (preadv64, preadv)
#endif