glibc/sysdeps/unix/sysv/linux/sendmmsg.c
Joseph Myers 0cb5da5c09 Simplify sendmmsg code.
Now we can assume a kernel with sendmmsg support, this patch
simplifies the implementation to be similar to that for accept4:
either using socketcall or the syscall according to whether the
syscall is known to be available, without further fallback
implementations.  The __ASSUME_SENDMMSG macro is kept (now defined
unconditionally), since it's used in resolv/res_send.c.

Tested for x86_64 and x86.

	* sysdeps/unix/sysv/linux/kernel-features.h
	(__ASSUME_SENDMMSG_SYSCALL): Define unconditionally.
	(__ASSUME_SENDMMSG): Likewise.
	(__ASSUME_SENDMMSG_SOCKETCALL): Remove macro.
	* sysdeps/unix/sysv/linux/sendmmsg.c (__sendmmsg): Define using
	sendmmsg syscall if that can be assumed to be present, socketcall
	otherwise, with no fallback for runtime failure.
2017-05-09 20:01:52 +00:00

43 lines
1.6 KiB
C

/* Copyright (C) 2011-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
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 <errno.h>
#include <sys/socket.h>
#include <sysdep-cancel.h>
#include <sys/syscall.h>
#include <socketcall.h>
#include <kernel-features.h>
int
__sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
{
/* Do not use the sendmmsg syscall on socketcall architectures unless
it was added at the same time as the socketcall support or can be
assumed to be present. */
#if defined __ASSUME_SOCKETCALL \
&& !defined __ASSUME_SENDMMSG_SYSCALL_WITH_SOCKETCALL \
&& !defined __ASSUME_SENDMMSG_SYSCALL
return SOCKETCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
#else
return SYSCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
#endif
}
libc_hidden_def (__sendmmsg)
weak_alias (__sendmmsg, sendmmsg)