glibc/misc/sys/uio.h
Adhemerval Zanella 52bd938169 posix: Implement preadv2 and pwritev2
This patch adds support of preadv2 and pwritev2 which are similar to
preadv/pwritev but with an extra flag argument.  As for preadv/pwritev
both interfaces are added a non-standard GNU API.

For default 'posix' implementation trying to emulate the Linux supported
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).

So default sysdeps/posix implementations fails with EOPNOTSUPP for any non
supported flag (which are none currently) calls generic preadv/pwritev.
Basically this implementation supports only preadv2 called as preadv (with
flags sets to 0).

The Linux one uses the preadv2/pwritev2 syscall if defined, otherwise it
call preadv/writev.  Instead of using the previous __ASSUME_* to
unconditionally issue the syscall (and avoid building the fallback routine),
it call pread/write if the preadv2/pwritev2 syscalls fails.  The idea
is just avoid adding another __ASSUME_* and checking each architecture
on every kernel bump and simplify code conditionals.

Checked on x86_64-linux-gnu and on i686-linux-gnu and a check with
run-built-tests=no on aarch64-linux-gnu, alpha-linux-gnu, arm-linux-gnueabihf,
ia64-linux-gnu, m68k-linux-gnu, microblaze-linux-gnu, mips{64,64n32}-linux-gnu,
nios2-linux-gnu, powerpc{64,64le}-linux-gnu, s390{x}-linux-gnu,
sparc{64,v9}-linux-gnu, tile{gx,pro}-linux-gnu, and sh4-linux-gnu (all using
gcc 6.3).

	* NEWS: Add note about pwritev2 and preadv2 inclusion.
	* misc/Makefile (routines): Add preadv2, preadv64v2, pwritev2, and
	pwritev64v2.
	(tests): Add tst-preadvwritev2 and tst-preadvwritev64v2.
	* misc/Versions (GLIBC_2.26): Add preadv2, preadv64v2, pwritev2, and
	pwritev64v2.
	* misc/preadv2.c: New file.
	* misc/preadv64v2.c: Likewise.
	* misc/pwritev2.c: Likewise.
	* misc/pwritev64v2.c: Likewise.
	* misc/tst-preadvwritev2.c: Likewise.
	* misc/tst-preadvwritev64v2.c: Likewise.
	* manual/llio.texi: Add preadv2 and pwritev2 documentation.
	* misc/sys/uio.h [__USE_GNU && !__USE_FILE_OFFSET64] (preadv2): New
	prototype.
	[__USE_GNU && !__USE_FILE_OFFSET64] (pwritev2):	Likewise.
	[__USE_GNU && __USE_FILE_OFFSET64] (preadv64v2): Likewise.
	[__USE_GNU && __USE_FILE_OFFSET64] (pwritev64v2): Likewise.
	* misc/tst-preadvwritev-common.c (PREADV): Define if not defined.
	(PWRITEV): Likewise.
	(do_test_with_offset): Use PREADV and PWRITEV macros and check for
	ENOSYS.
	* nptl/tst-cancel4.c (tf_pwritev2): New test.
	(tf_preadv2): Likewise.
	(tf_fsync): Add tf_pwritev2 and tf_preadv2.
	* sysdeps/posix/preadv2.c: Likewise.
	* sysdeps/posix/preadv64v2.c: Likewise.
	* sysdeps/posix/pwritev2.c: Likewise.
	* sysdeps/posix/pwritev64v2.c: Likewise.
	* sysdeps/unix/sysv/linux/kernel-features.h: Add comment for syscall
	support in kernel.
	* sysdeps/unix/sysv/linux/preadv2.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv64v2.c: Likewise.
	* sysdeps/unix/sysv/linux/pwritev2.c: Likewise.
	* sysdeps/unix/sysv/linux/pwritev64v2.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv.c (preadv): Add libc_hidden_def.
	* sysdeps/unix/sysv/linux/preadv64.c (preadv64): Likewise.
	* sysdeps/unix/sysv/linux/pwritev.c (pwritev): Likewise.
	* sysdeps/unix/sysv/linux/pwritev64.c (pwritev64): Likewise.
	* sysdeps/unix/sysv/linux/bits/uio.h: Add supported preadv2/pwritev2
	support flags on Linux.
	* sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.26): Add
	preadv2, preadv64v2, pwritev2, pwritev64v2.
	* sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/arm/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/hppa/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/i386/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/ia64/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/nios2/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
	(GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
	(GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
	(GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/sh/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/sysv/linux/tile/tilegx/tilegx32/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/sysv/linux/tile/tilegx/tilegx64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist (GLIBC_2.26):
	Likewise.
2017-05-31 17:35:46 -03:00

164 lines
5.9 KiB
C

/* Copyright (C) 1991-2017 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/>. */
#ifndef _SYS_UIO_H
#define _SYS_UIO_H 1
#include <features.h>
#include <sys/types.h>
__BEGIN_DECLS
/* This file defines `struct iovec'. */
#include <bits/uio.h>
/* Read data from file descriptor FD, and put the result in the
buffers described by IOVEC, which is a vector of COUNT 'struct iovec's.
The buffers are filled in the order specified.
Operates just like 'read' (see <unistd.h>) except that data are
put in IOVEC instead of a contiguous buffer.
This function is a cancellation point and therefore not marked with
__THROW. */
extern ssize_t readv (int __fd, const struct iovec *__iovec, int __count)
__wur;
/* Write data pointed by the buffers described by IOVEC, which
is a vector of COUNT 'struct iovec's, to file descriptor FD.
The data is written in the order specified.
Operates just like 'write' (see <unistd.h>) except that the data
are taken from IOVEC instead of a contiguous buffer.
This function is a cancellation point and therefore not marked with
__THROW. */
extern ssize_t writev (int __fd, const struct iovec *__iovec, int __count)
__wur;
#ifdef __USE_MISC
# ifndef __USE_FILE_OFFSET64
/* Read data from file descriptor FD at the given position OFFSET
without change the file pointer, and put the result in the buffers
described by IOVEC, which is a vector of COUNT 'struct iovec's.
The buffers are filled in the order specified. Operates just like
'pread' (see <unistd.h>) except that data are put in IOVEC instead
of a contiguous buffer.
This function is a cancellation point and therefore not marked with
__THROW. */
extern ssize_t preadv (int __fd, const struct iovec *__iovec, int __count,
__off_t __offset) __wur;
/* Write data pointed by the buffers described by IOVEC, which is a
vector of COUNT 'struct iovec's, to file descriptor FD at the given
position OFFSET without change the file pointer. The data is
written in the order specified. Operates just like 'pwrite' (see
<unistd.h>) except that the data are taken from IOVEC instead of a
contiguous buffer.
This function is a cancellation point and therefore not marked with
__THROW. */
extern ssize_t pwritev (int __fd, const struct iovec *__iovec, int __count,
__off_t __offset) __wur;
# else
# ifdef __REDIRECT
extern ssize_t __REDIRECT (preadv, (int __fd, const struct iovec *__iovec,
int __count, __off64_t __offset),
preadv64) __wur;
extern ssize_t __REDIRECT (pwritev, (int __fd, const struct iovec *__iovec,
int __count, __off64_t __offset),
pwritev64) __wur;
# else
# define preadv preadv64
# define pwritev pwritev64
# endif
# endif
# ifdef __USE_LARGEFILE64
/* Read data from file descriptor FD at the given position OFFSET
without change the file pointer, and put the result in the buffers
described by IOVEC, which is a vector of COUNT 'struct iovec's.
The buffers are filled in the order specified. Operates just like
'pread' (see <unistd.h>) except that data are put in IOVEC instead
of a contiguous buffer.
This function is a cancellation point and therefore not marked with
__THROW. */
extern ssize_t preadv64 (int __fd, const struct iovec *__iovec, int __count,
__off64_t __offset) __wur;
/* Write data pointed by the buffers described by IOVEC, which is a
vector of COUNT 'struct iovec's, to file descriptor FD at the given
position OFFSET without change the file pointer. The data is
written in the order specified. Operates just like 'pwrite' (see
<unistd.h>) except that the data are taken from IOVEC instead of a
contiguous buffer.
This function is a cancellation point and therefore not marked with
__THROW. */
extern ssize_t pwritev64 (int __fd, const struct iovec *__iovec, int __count,
__off64_t __offset) __wur;
# endif
#endif /* Use misc. */
#ifdef __USE_GNU
# ifndef __USE_FILE_OFFSET64
/* Same as preadv but with an additional flag argumenti defined at uio.h. */
extern ssize_t preadv2 (int __fp, const struct iovec *__iovec, int __count,
__off_t __offset, int ___flags) __wur;
/* Same as preadv but with an additional flag argument defined at uio.h. */
extern ssize_t pwritev2 (int __fd, const struct iovec *__iodev, int __count,
__off_t __offset, int __flags) __wur;
# else
# ifdef __REDIRECT
extern ssize_t __REDIRECT (pwritev2, (int __fd, const struct iovec *__iovec,
int __count, __off64_t __offset,
int __flags),
pwritev64v2) __wur;
extern ssize_t __REDIRECT (preadv2, (int __fd, const struct iovec *__iovec,
int __count, __off64_t __offset,
int __flags),
preadv64v2) __wur;
# else
# define preadv2 preadv64v2
# define pwritev2 pwritev64v2
# endif
# endif
# ifdef __USE_LARGEFILE64
/* Same as preadv but with an additional flag argumenti defined at uio.h. */
extern ssize_t preadv64v2 (int __fp, const struct iovec *__iovec,
int __count, __off64_t __offset,
int ___flags) __wur;
/* Same as preadv but with an additional flag argument defined at uio.h. */
extern ssize_t pwritev64v2 (int __fd, const struct iovec *__iodev,
int __count, __off64_t __offset,
int __flags) __wur;
# endif
#endif /* Use GNU. */
__END_DECLS
#endif /* sys/uio.h */