glibc/sysdeps/unix/sysv/linux/recvmmsg.c
Adhemerval Zanella 222c2d7f43 network: recvmmsg and sendmmsg standard compliance (BZ#16919)
POSIX specifies that both msghdr::msg_iovlen and msghdr::msg_controllen
to be of size int and socklen_t respectively, however Linux implements
it as a size_t.  So for 64-bits architecture where sizeof of size_t is
larger than socklen_t, both sendmmsg and recvmmsg need to adjust the
mmsghdr::msg_hdr internal fields before issuing the syscall itself.

This patch fixes it by operating on the padding if it the case.
For recvmmsg, the most straightfoward case, only zero padding the fields
is suffice.  However, for sendmmsg, where adjusting the buffer is out
of the contract (since it may point to a read-only data), the function
is rewritten to use sendmsg instead (which from previous patch
allocates a temporary msghdr to operate on).

Also for 64-bit ports that requires it, a new recvmmsg and sendmmsg
compat version is created (which uses size_t for both cmsghdr::cmsg_len
and internal

Tested on x86_64, i686, aarch64, armhf, and powerpc64le.

	* sysdeps/unix/sysv/linux/Makefile
	[$(subdir) = socket] (sysdep_routines): Add oldrecvmmsg and
	oldsendmmsg.
	* sysdeps/unix/sysv/linux/aarch64/libc.abilist: Add recvmmsg and
	sendmmsg.
	* sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/ia64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist: Likewise.
	* sysdeps/sysv/linux/powerpc/powerpc64/libc-le.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/oldrecvmmsg.c: New file.
	* sysdeps/unix/sysv/linux/oldsendmmsg.c: Likewise.
	* sysdeps/unix/sysv/linux/recvmmsg.c (__recvmmsg): Adjust msghdr
	iovlen and controllen fields to adjust to POSIX specification.
	* sysdeps/unix/sysv/linux/sendmmsg.c (__sendmmsg): Likewise.
2016-05-25 17:39:07 -03:00

111 lines
3.3 KiB
C

/* 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 <sys/socket.h>
#include <socketcall.h>
#include <sysdep-cancel.h>
#include <shlib-compat.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
static inline void
adjust_mmsghdr (struct mmsghdr *vmessages, unsigned int vlen)
{
#if __WORDSIZE == 64
/* POSIX specifies that both msghdr::msg_iovlen and msghdr::msg_controllen
to be int and socklen_t respectively. However Linux defines it as
both size_t. So for 64-bit it requires some adjustments by zeroing
the pad fields. */
struct mmsghdr *vmhdr = vmessages;
for (unsigned int i = 0; i != 0; i--, vmhdr++)
{
vmhdr->msg_hdr.__glibc_reserved1 = 0;
vmhdr->msg_hdr.__glibc_reserved2 = 0;
}
#endif
}
int
__recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen,
int flags, struct timespec *tmo)
{
#ifdef __NR_recvmmsg
adjust_mmsghdr (vmessages, vlen);
return SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo);
#elif defined __NR_socketcall
# ifdef __ASSUME_RECVMMSG_SOCKETCALL
adjust_mmsghdr (vmessages, vlen);
return SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo);
# else
static int have_recvmmsg;
if (__glibc_likely (have_recvmmsg >= 0))
{
adjust_mmsghdr (vmessages, vlen);
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
# define STUB 1
__set_errno (ENOSYS);
return -1;
#endif
}
#ifdef STUB
stub_warning (recvmmsg)
#endif
#if __WORDSIZE == 64
versioned_symbol (libc, __recvmmsg, recvmmsg, GLIBC_2_24);
#else
weak_alias (__recvmmsg, recvmmsg)
#endif