glibc/sysdeps/unix/sysv/linux/ppoll.c
Lukasz Majewski 258c242128 y2038: linux: Provide __ppoll64 implementation
This patch provides new __ppoll64 explicit 64 bit function for handling polling
events (with struct timespec specified timeout) for a set of file descriptors.
Moreover, a 32 bit version - __ppoll has been refactored to internally use
__ppoll64.

The __ppoll is now supposed to be used on systems still supporting 32 bit time
(__TIMESIZE != 64) - hence the necessary conversion to 64 bit struct
__timespec64.

The new ppoll_time64 syscall available from Linux 5.1+ has been used, when
applicable.

The Linux kernel checks if passed tv_nsec value overflows, so there is no need
to repeat it in the glibc.

When ppoll syscall on systems supporting 32 bit time ABI is used, the check is
performed if passed data (which may have 64 bit tv_sec) fits into 32 bit range.

Build tests:
- The code has been tested on x86_64/x86 (native compilation):
make PARALLELMFLAGS="-j8" && make check PARALLELMFLAGS="-j8" && \\
make xcheck PARALLELMFLAGS="-j8"

- The glibc has been build tested (make PARALLELMFLAGS="-j8") for
x86 (i386), x86_64-x32, and armv7

Run-time tests:
- Run specific tests on ARM/x86 32bit systems (qemu):
  https://github.com/lmajewski/meta-y2038 and run tests:
  https://github.com/lmajewski/y2038-tests/commits/master

- Use of cross-test-ssh.sh for ARM (armv7):
  make PARALLELMFLAGS="-j8" test-wrapper='./cross-test-ssh.sh root@192.168.7.2' xcheck

Linux kernel, headers and minimal kernel version for glibc build test
matrix:
- Linux v5.1 (with ppoll_time64) and glibc build with v5.1 as
  minimal kernel version (--enable-kernel="5.1.0")
  The __ASSUME_TIME64_SYSCALLS flag defined.

- Linux v5.1 and default minimal kernel version
  The __ASSUME_TIME64_SYSCALLS not defined, but kernel supports ppoll_time64
  syscall.

- Linux v4.19 (no ppoll_time64 support) with default minimal kernel version for
  contemporary glibc
  This kernel doesn't support ppoll_time64 syscall, so the fallback to ppoll is
  tested.

Above tests were performed with Y2038 redirection applied as well as without
(so the __TIMESIZE != 64 execution path is checked as well).

No regressions were observed.
2019-11-11 14:41:43 +01:00

83 lines
2.4 KiB
C

/* Copyright (C) 2006-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2006.
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 <errno.h>
#include <signal.h>
#include <time.h>
#include <sys/poll.h>
#include <sysdep-cancel.h>
#include <kernel-features.h>
int
__ppoll64 (struct pollfd *fds, nfds_t nfds, const struct __timespec64 *timeout,
const sigset_t *sigmask)
{
/* The Linux kernel can in some situations update the timeout value.
We do not want that so use a local variable. */
struct __timespec64 tval;
if (timeout != NULL)
{
tval = *timeout;
timeout = &tval;
}
#ifdef __ASSUME_TIME64_SYSCALLS
# ifndef __NR_ppoll_time64
# define __NR_ppoll_time64 __NR_ppoll
# endif
return SYSCALL_CANCEL (ppoll_time64, fds, nfds, timeout, sigmask, _NSIG / 8);
#else
# ifdef __NR_ppoll_time64
int ret = SYSCALL_CANCEL (ppoll_time64, fds, nfds, timeout, sigmask,
_NSIG / 8);
if (ret >= 0 || errno != ENOSYS)
return ret;
# endif
struct timespec ts32;
if (timeout)
{
if (! in_time_t_range (timeout->tv_sec))
{
__set_errno (EOVERFLOW);
return -1;
}
ts32 = valid_timespec64_to_timespec (*timeout);
}
return SYSCALL_CANCEL (ppoll, fds, nfds, timeout ? &ts32 : NULL, sigmask,
_NSIG / 8);
#endif
}
#if __TIMESIZE != 64
int
__ppoll (struct pollfd *fds, nfds_t nfds, const struct timespec *timeout,
const sigset_t *sigmask)
{
struct __timespec64 ts64;
if (timeout)
ts64 = valid_timespec_to_timespec64 (*timeout);
return __ppoll64 (fds, nfds, timeout ? &ts64 : NULL, sigmask);
}
#endif
strong_alias (__ppoll, ppoll)
libc_hidden_def (ppoll)