2012-04-17 02:52:56 +00:00
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/* Set flags signalling availability of kernel features based on given
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kernel version number.
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2014-01-01 11:03:15 +00:00
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Copyright (C) 2010-2014 Free Software Foundation, Inc.
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2012-04-17 02:52:56 +00:00
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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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#ifndef _KERNEL_FEATURES_H
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#define _KERNEL_FEATURES_H 1
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/* The utimes syscall has been available for some architectures
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forever. */
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#define __ASSUME_UTIMES 1
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/* pselect/ppoll were introduced just after 2.6.16-rc1. Due to the way
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the kernel versions are advertised we can only rely on 2.6.17 to have
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the code. */
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#if __LINUX_KERNEL_VERSION >= 0x020616
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# define __ASSUME_PSELECT 1
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# define __ASSUME_PPOLL 1
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#endif
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/* Support for various CLOEXEC and NONBLOCK flags was added in 2.6.23. */
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#if __LINUX_KERNEL_VERSION >= 0x020617
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# define __ASSUME_O_CLOEXEC 1
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#endif
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/* Support for various CLOEXEC and NONBLOCK flags was added in 2.6.27. */
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#if __LINUX_KERNEL_VERSION >= 0x02061b
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# define __ASSUME_SOCK_CLOEXEC 1
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# define __ASSUME_IN_NONBLOCK 1
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# define __ASSUME_PIPE2 1
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# define __ASSUME_EVENTFD2 1
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# define __ASSUME_SIGNALFD4 1
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# define __ASSUME_DUP3 1
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#endif
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2012-04-17 02:55:11 +00:00
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/* Support for the accept4 syscall was added in 3.3. */
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#if __LINUX_KERNEL_VERSION >= 0x030300
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Fix __ASSUME_ACCEPT4 issues (bug 16609).
In <https://sourceware.org/ml/libc-alpha/2013-12/msg00008.html>,
Aurelien noted issues with the definition of __ASSUME_ACCEPT4, which I
discussed in more detail in
<https://sourceware.org/ml/libc-alpha/2013-12/msg00014.html>; these
are now bug 16609.
As previously noted, __ASSUME_ACCEPT4 is used in two ways:
* In OS-independent code, to mean "accept4 can be assumed to work
rather than fail with ENOSYS". It doesn't matter whether it's
implemented with socketcall or a separate syscall.
* In Linux-specific code, to mean "the socketcall multiplex syscall
can be assumed to handle the accept4 operation. When used in
Linux-specific code, it *never* refers to anything relating to the
accept4 syscall, only to the socketcall multiplexer.
This patch splits the macro into separate __ASSUME_ACCEPT4_SOCKETCALL,
__ASSUME_ACCEPT4_SYSCALL and __ASSUME_ACCEPT4 to clarify the different
cases involved. A macro __ASSUME_SOCKETCALL is added for convenience
in writing logic relating to all socketcall architectures. In
addition, to address the issue of architectures where socketcall
support for accept4 was added before a separate syscall was added (and
so the separate syscall should not be used unless known to be present
or fallback to socketcall is available), a fourth macro
__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL is added to indicate that the
syscall became available at the same time as socketcall support. This
is then used in the relevant places in a conditional determining
whether to undefine __NR_accept4 (the simple approach to avoiding the
syscall's presence causing problems; I didn't try to implement runtime
fallback from the syscall to socketcall).
Architecture-specific note: alpha defined __ASSUME_ACCEPT4 for 2.6.33
and later, but actually the syscall was added for alpha in 3.2, so
this patch uses the correct condition for __ASSUME_ACCEPT4_SYSCALL
there.
Tested x86_64, including that disassembly of the installed shared
libraries is unchanged by this patch.
[BZ #16609]
* sysdeps/unix/sysv/linux/kernel-features.h [__i386__ ||
__powerpc__ || __s390__ || __sh__ || __sparc__]
(__ASSUME_SOCKETCALL): Define.
[__LINUX_KERNEL_VERSION && __ASSUME_SOCKETCALL]
(__ASSUME_ACCEPT4_SOCKETCALL): Likewise.
[(__LINUX_KERNEL_VERSION >= 0x02061c && (__x86_64__ || __sparc__))
|| (__LINUX_KERNEL_VERSION >= 0x020625 && (__powerpc__ ||
__sh__))] (__ASSUME_ACCEPT4_SYSCALL): Likewise.
[__sparc__] (__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL): Likewise.
[__ASSUME_ACCEPT4_SOCKETCALL || __ASSUME_ACCEPT4_SYSCALL]
(__ASSUME_ACCEPT4): Define instead of using previous
[__LINUX_KERNEL_VERSION >= 0x02061c && (__i386__ || __x86_64__ ||
__powerpc__ || __sparc__ || __s390__)] condition.
* sysdeps/unix/sysv/linux/aarch64/kernel-features.h
(__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/accept4.c [__ASSUME_SOCKETCALL &&
!__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL &&
!__ASSUME_ACCEPT4_SYSCALL] (__NR_accept4): Undefine.
[!__ASSUME_ACCEPT4]: Change condition to
[!__ASSUME_ACCEPT4_SOCKETCALL].
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
(__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL. Correct
condition to [__LINUX_KERNEL_VERSION >= 0x030200].
* sysdeps/unix/sysv/linux/arm/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020624] (__ASSUME_ACCEPT4): Change to
__ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/i386/accept4.S [__ASSUME_ACCEPT4]:
Change conditions to [__ASSUME_ACCEPT4_SOCKETCALL].
* sysdeps/unix/sysv/linux/ia64/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x030300] (__ASSUME_ACCEPT4): Change to
__ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/internal_accept4.S [__ASSUME_SOCKETCALL
&& !__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL &&
!__ASSUME_ACCEPT4_SYSCALL] (__NR_accept4): Undefine.
[__ASSUME_ACCEPT4]: Change condition to
[__ASSUME_ACCEPT4_SOCKETCALL].
* sysdeps/unix/sysv/linux/m68k/kernel-features.h
(__ASSUME_SOCKETCALL): Define.
[__LINUX_KERNEL_VERSION >= 0x02061c] (__ASSUME_ACCEPT4): Remove.
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
(__ASSUME_SOCKETCALL): Define.
(__ASSUME_ACCEPT4): Remove.
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_ACCEPT4_SYSCALL):
Define.
* sysdeps/unix/sysv/linux/mips/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x02061f] (__ASSUME_ACCEPT4_SYSCALL):
Likewise.
* sysdeps/unix/sysv/linux/tile/kernel-features.h
(__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/hppa/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020622] (__ASSUME_ACCEPT4_SYSCALL):
Define.
2014-02-20 17:50:31 +00:00
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# define __ASSUME_ACCEPT4_SYSCALL 1
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2012-04-17 02:55:11 +00:00
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#endif
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2012-04-17 02:52:56 +00:00
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#include_next <kernel-features.h>
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#endif /* _KERNEL_FEATURES_H */
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