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glibc/sysdeps/unix/sysv/linux/recvmmsg.c
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/* Copyright (C) 2010-2016 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Andreas Schwab <schwab@redhat.com>, 2010. | |
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 recvmmsg 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_RECVMMSG_SYSCALL_WITH_SOCKETCALL \ | |
&& !defined __ASSUME_RECVMMSG_SYSCALL | |
# undef __NR_recvmmsg | |
#endif | |
#ifdef __NR_recvmmsg | |
int | |
recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags, | |
struct timespec *tmo) | |
{ | |
return SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo); | |
} | |
#elif defined __NR_socketcall | |
# include <socketcall.h> | |
# ifdef __ASSUME_RECVMMSG_SOCKETCALL | |
int | |
recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags, | |
struct timespec *tmo) | |
{ | |
return SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo); | |
} | |
# else | |
static int have_recvmmsg; | |
int | |
recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags, | |
struct timespec *tmo) | |
{ | |
if (__glibc_likely (have_recvmmsg >= 0)) | |
{ | |
int ret = SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, | |
tmo); | |
/* 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_recvmmsg == 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_recvmmsg = -1; | |
__set_errno (ENOSYS); | |
} | |
else | |
{ | |
have_recvmmsg = 1; | |
__set_errno (EINVAL); | |
} | |
return -1; | |
} | |
return ret; | |
} | |
__set_errno (ENOSYS); | |
return -1; | |
} | |
# endif /* __ASSUME_RECVMMSG_SOCKETCALL */ | |
#else | |
# include <socket/recvmmsg.c> | |
#endif |