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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.
79 lines
2.5 KiB
C
79 lines
2.5 KiB
C
/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#if !defined _SYS_UIO_H && !defined _FCNTL_H
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# error "Never include <bits/uio.h> directly; use <sys/uio.h> instead."
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#endif
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#ifndef _BITS_UIO_H
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#define _BITS_UIO_H 1
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#include <sys/types.h>
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/* We should normally use the Linux kernel header file to define this
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type and macros but this calls for trouble because of the header
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includes other kernel headers. */
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/* Size of object which can be written atomically.
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This macro has different values in different kernel versions. The
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latest versions of the kernel use 1024 and this is good choice. Since
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the C library implementation of readv/writev is able to emulate the
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functionality even if the currently running kernel does not support
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this large value the readv/writev call will not fail because of this. */
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#define UIO_MAXIOV 1024
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#include <bits/types/struct_iovec.h>
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#endif
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#ifdef __USE_GNU
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# if defined _SYS_UIO_H && !defined _BITS_UIO_H_FOR_SYS_UIO_H
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# define _BITS_UIO_H_FOR_SYS_UIO_H 1
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__BEGIN_DECLS
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/* Read from another process' address space. */
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extern ssize_t process_vm_readv (pid_t __pid, const struct iovec *__lvec,
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unsigned long int __liovcnt,
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const struct iovec *__rvec,
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unsigned long int __riovcnt,
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unsigned long int __flags)
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__THROW;
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/* Write to another process' address space. */
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extern ssize_t process_vm_writev (pid_t __pid, const struct iovec *__lvec,
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unsigned long int __liovcnt,
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const struct iovec *__rvec,
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unsigned long int __riovcnt,
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unsigned long int __flags)
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__THROW;
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__END_DECLS
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# endif
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/* Flags for preadv2/pwritev2: */
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#define RWF_HIPRI 0x00000001 /* High priority request. */
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#define RWF_DSYNC 0x00000002 /* per-IO O_DSYNC. */
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#define RWF_SYNC 0x00000004 /* per-IO O_SYNC. */
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#endif
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