glibc/sysdeps/unix/sysv/linux/sendmmsg.c

94 lines
2.8 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 <kernel-features.h>
/* 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
# undef __NR_sendmmsg
#endif
#ifdef __NR_sendmmsg
int
__sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
{
return SYSCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
}
libc_hidden_def (__sendmmsg)
weak_alias (__sendmmsg, sendmmsg)
#elif defined __NR_socketcall
# include <socketcall.h>
# ifdef __ASSUME_SENDMMSG_SOCKETCALL
int
__sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
{
return SOCKETCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
}
# else
static int have_sendmmsg;
int
__sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
{
if (__glibc_likely (have_sendmmsg >= 0))
{
int ret = SOCKETCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
/* The kernel returns -EINVAL for unknown socket operations.
We need to convert that error to an ENOSYS error. */
if (__builtin_expect (ret < 0, 0)
&& have_sendmmsg == 0
&& errno == EINVAL)
{
/* Try another call, this time with an invalid file
descriptor and all other parameters cleared. This call
will not cause any harm and it will return
immediately. */
ret = SOCKETCALL_CANCEL (invalid, -1);
if (errno == EINVAL)
{
have_sendmmsg = -1;
__set_errno (ENOSYS);
}
else
{
have_sendmmsg = 1;
__set_errno (EINVAL);
}
return -1;
}
return ret;
}
__set_errno (ENOSYS);
return -1;
}
# endif /* __ASSUME_SENDMMSG_SOCKETCALL */
libc_hidden_def (__sendmmsg)
weak_alias (__sendmmsg, sendmmsg)
#else
# include <socket/sendmmsg.c>
#endif