glibc/sysdeps/unix/sysv/linux/recvmmsg.c
Adhemerval Zanella 948ce73b31 Linux: Only generate 64 bit timestamps for 64 bit time_t recvmsg/recvmmsg
The timestamps created by __convert_scm_timestamps only make sense for
64 bit time_t programs, 32 bit time_t programs will ignore 64 bit time_t
timestamps since SO_TIMESTAMP will be defined to old values (either by
glibc or kernel headers).

Worse, if the buffer is not suffice MSG_CTRUNC is set to indicate it
(which breaks some programs [1]).

This patch makes only 64 bit time_t recvmsg and recvmmsg to call
__convert_scm_timestamps.  Also, the assumption to called it is changed
from __ASSUME_TIME64_SYSCALLS to __TIMESIZE != 64 since the setsockopt
might be called by libraries built without __TIME_BITS=64.  The
MSG_CTRUNC is only set for the 64 bit symbols, it should happen only
if 64 bit time_t programs run older kernels.

Checked on x86_64-linux-gnu and i686-linux-gnu.

[1] https://github.com/systemd/systemd/pull/20567

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-01-28 18:18:27 -03:00

104 lines
2.9 KiB
C

/* Copyright (C) 2010-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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
<https://www.gnu.org/licenses/>. */
#include <sys/socket.h>
#include <sysdep.h>
#include <socketcall.h>
static int
recvmmsg_syscall (int fd, struct mmsghdr *vmessages, unsigned int vlen,
int flags, struct __timespec64 *timeout)
{
#ifndef __NR_recvmmsg_time64
# define __NR_recvmmsg_time64 __NR_recvmmsg
#endif
int r = SYSCALL_CANCEL (recvmmsg_time64, fd, vmessages, vlen, flags,
timeout);
#ifndef __ASSUME_TIME64_SYSCALLS
if (r >= 0 || errno != ENOSYS)
return r;
struct timespec ts32, *pts32 = NULL;
if (timeout != NULL)
{
if (! in_time_t_range (timeout->tv_sec))
{
__set_errno (EINVAL);
return -1;
}
ts32 = valid_timespec64_to_timespec (*timeout);
pts32 = &ts32;
}
# ifdef __ASSUME_RECVMMSG_SYSCALL
r = SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, pts32);
# else
r = SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, pts32);
# endif
if (r >= 0)
{
if (timeout != NULL)
*timeout = valid_timespec_to_timespec64 (ts32);
}
#endif
return r;
}
int
__recvmmsg64 (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
struct __timespec64 *timeout)
{
#if __TIMESIZE != 64
socklen_t csize[IOV_MAX];
if (vlen > IOV_MAX)
vlen = IOV_MAX;
for (int i = 0; i < vlen; i++)
csize[i] = vmessages[i].msg_hdr.msg_controllen;
#endif
int r = recvmmsg_syscall (fd, vmessages, vlen, flags, timeout);
#if __TIMESIZE != 64
if (r > 0)
{
for (int i=0; i < r; i++)
__convert_scm_timestamps (&vmessages[i].msg_hdr, csize[i]);
}
#endif
return r;
}
#if __TIMESIZE != 64
libc_hidden_def (__recvmmsg64)
int
__recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
struct timespec *timeout)
{
struct __timespec64 ts64, *pts64 = NULL;
if (timeout != NULL)
{
ts64 = valid_timespec_to_timespec64 (*timeout);
pts64 = &ts64;
}
int r = recvmmsg_syscall (fd, vmessages, vlen, flags, pts64);
if (r >= 0 && timeout != NULL)
/* The remanining timeout will be always less the input TIMEOUT. */
*timeout = valid_timespec64_to_timespec (ts64);
return r;
}
#endif
weak_alias (__recvmmsg, recvmmsg)