mirror of git://sourceware.org/git/glibc.git
124 lines
3.9 KiB
C
124 lines
3.9 KiB
C
/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
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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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#include <sys/socket.h>
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#include <socketcall.h>
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#include <sysdep-cancel.h>
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#include <shlib-compat.h>
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/* Do not use the sendmmsg syscall on socketcall architectures unless
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it was added at the same time as the socketcall support or can be
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assumed to be present. */
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#if defined __ASSUME_SOCKETCALL \
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&& !defined __ASSUME_SENDMMSG_SYSCALL_WITH_SOCKETCALL \
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&& !defined __ASSUME_SENDMMSG_SYSCALL
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# undef __NR_sendmmsg
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#endif
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#if __WORDSIZE == 64
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static inline int
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send_mmsghdr (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
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{
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/* Emulate kernel interface for vlen size. */
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if (vlen > IOV_MAX)
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vlen = IOV_MAX;
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if (vlen == 0)
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return 0;
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/* POSIX specifies that both msghdr::msg_iovlen and msghdr::msg_controllen
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to be int and socklen_t respectively, however Linux defines it as both
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size_t. So for 64-bit it requires some adjustments by copying to
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temporary header and zeroing the pad fields.
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The problem is sendmmsg's msghdr may points to an already-filled control
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buffer and modifying it is not part of sendmmsg contract (the data may
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be in ro map). So interact over the msghdr calling the sendmsg that
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adjust the header using a temporary buffer. */
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for (unsigned int i = 0; i < vlen; i++)
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{
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ssize_t ret = __sendmsg (fd, &vmessages[i].msg_hdr, flags);
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if (ret < 0)
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return -1;
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vmessages[i].msg_len = ret;
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}
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return 1;
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}
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#endif
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int
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__sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
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{
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#if __WORDSIZE == 64
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return send_mmsghdr (fd, vmessages, vlen, flags);
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#elif defined __NR_sendmmsg
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return SYSCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
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#elif defined __NR_socketcall
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# ifdef __ASSUME_SENDMMSG_SOCKETCALL
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return SOCKETCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
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# else
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static int have_sendmmsg;
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if (__glibc_likely (have_sendmmsg >= 0))
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{
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# if __WORDSIZE == 64
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int ret = send_mmsghdr (fd, vmessages, vlen, flags);
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# else
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int ret = SOCKETCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
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# endif
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/* The kernel returns -EINVAL for unknown socket operations.
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We need to convert that error to an ENOSYS error. */
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if (__builtin_expect (ret < 0, 0)
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&& have_sendmmsg == 0
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&& errno == EINVAL)
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{
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/* Try another call, this time with an invalid file
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descriptor and all other parameters cleared. This call
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will not cause any harm and it will return
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immediately. */
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ret = SOCKETCALL_CANCEL (invalid, -1);
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if (errno == EINVAL)
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{
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have_sendmmsg = -1;
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__set_errno (ENOSYS);
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}
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else
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{
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have_sendmmsg = 1;
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__set_errno (EINVAL);
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}
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return -1;
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}
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return ret;
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}
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__set_errno (ENOSYS);
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return -1;
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# endif /* __ASSUME_SENDMMSG_SOCKETCALL */
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#else /* defined __NR_socketcall */
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# define STUB 1
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__set_errno (ENOSYS);
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return -1;
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#endif
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}
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#ifdef STUB
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stub_warning (sendmmsg)
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#endif
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libc_hidden_def (__sendmmsg)
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#if __WORDSIZE == 64
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versioned_symbol (libc, __sendmmsg, sendmmsg, GLIBC_2_24);
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#else
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weak_alias (__sendmmsg, sendmmsg)
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#endif
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