Re: [PATCH v4 5/8] linux: Use long time_t __getitimer/__setitimer

[Lukasz Majewski <lukma at denx dot de>]

Hi Alistair,

> The Linux kernel expects itimerval to use a 32-bit time_t, even on
> archs with a 64-bit time_t (like RV32). To address this let's convert
> itimerval to/from 32-bit and 64-bit to ensure the kernel always gets
> a 32-bit time_t.
> 
> While we are converting these functions let's also convert them to be
> the y2038 safe versions. This means there is a *64 function that is
> called by a backwards compatible wrapper.
> ---
>  include/time.h                        | 15 +++++
>  sysdeps/unix/syscalls.list            |  2 -
>  sysdeps/unix/sysv/linux/getitimer.c   | 59 +++++++++++++++++
>  sysdeps/unix/sysv/linux/setitimer.c   | 95
> +++++++++++++++++++++++++++ sysdeps/unix/sysv/linux/tv32-compat.h |
> 31 +++++++++ 5 files changed, 200 insertions(+), 2 deletions(-)
>  create mode 100644 sysdeps/unix/sysv/linux/getitimer.c
>  create mode 100644 sysdeps/unix/sysv/linux/setitimer.c
>  create mode 100644 sysdeps/unix/sysv/linux/tv32-compat.h
> 
> diff --git a/include/time.h b/include/time.h
> index 8a4abb159f..eaa536d5c0 100644
> --- a/include/time.h
> +++ b/include/time.h
> @@ -6,6 +6,7 @@
>  # include <bits/types/locale_t.h>
>  # include <stdbool.h>
>  # include <time/mktime-internal.h>
> +# include <sys/time.h>
>  # include <endian.h>
>  # include <time-clockid.h>
>  # include <sys/time.h>
> @@ -119,6 +120,20 @@ struct __itimerval64
>  };
>  #endif
>  
> +#if __TIMESIZE == 64
> +# define __getitimer64 __getitimer
> +# define __setitimer64 __setitimer
> +#else
> +extern int __getitimer64 (enum __itimer_which __which,
> +                          struct __itimerval64 *__value);
> +
> +libc_hidden_proto (__getitimer64)
> +extern int __setitimer64 (enum __itimer_which __which,
> +                          const struct __itimerval64 *__restrict
> __new,
> +                          struct __itimerval64 *__restrict __old);
> +libc_hidden_proto (__setitimer64)
> +#endif
> +
>  #if __TIMESIZE == 64
>  # define __ctime64 ctime
>  #else
> diff --git a/sysdeps/unix/syscalls.list b/sysdeps/unix/syscalls.list
> index e28e801c7a..d249049d6e 100644
> --- a/sysdeps/unix/syscalls.list
> +++ b/sysdeps/unix/syscalls.list
> @@ -25,7 +25,6 @@ getgid		-	getgid
> 	Ei:	__getgid	getgid getgroups	-
> getgroups	i:ip	__getgroups	getgroups
> gethostid	-	gethostid	i:	gethostid
> gethostname	-	gethostname	i:bn
> __gethostname	gethostname -getitimer	-
> getitimer	i:ip	__getitimer	getitimer
> getpeername	-	getpeername	i:ibN
> __getpeername	getpeername getpid		-
> getpid		Ei:	__getpid	getpid
> getpriority	-	getpriority	i:ii
> __getpriority	getpriority @@ -67,7 +66,6 @@ setgid
> 	-	setgid		i:i	__setgid
> setgid setgroups	-	setgroups	i:ip
> setgroups sethostid	-	sethostid	i:i
> sethostid sethostname	-	sethostname	i:pi
> sethostname -setitimer	-	setitimer	i:ipp
> __setitimer	setitimer setpgid		-
> setpgrp		i:ii	__setpgid	setpgid
> setpriority	-	setpriority	i:iii
> __setpriority	setpriority setregid	-
> setregid	i:ii	__setregid	setregid diff --git
> a/sysdeps/unix/sysv/linux/getitimer.c
> b/sysdeps/unix/sysv/linux/getitimer.c new file mode 100644 index
> 0000000000..12f7963949 --- /dev/null +++
> b/sysdeps/unix/sysv/linux/getitimer.c @@ -0,0 +1,59 @@ +/* getitimer
> -- Get the state of an interval timer.  Linux/tv32 version.
> +   Copyright (C) 2020 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
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <time.h>
> +#include <sys/time.h>
> +#include <sys/types.h>
> +#include <sysdep.h>
> +#include <tv32-compat.h>
> +
> +int
> +__getitimer64 (__itimer_which_t which, struct __itimerval64
> *curr_value) +{
> +#if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
> +  return INLINE_SYSCALL_CALL (getitimer, which, curr_value);
> +#else
> +  struct __itimerval32 curr_value_32;
> +  if (INLINE_SYSCALL_CALL (getitimer, which, &curr_value_32) == -1)
> +    return -1;
> +
> +  /* Write all fields of 'curr_value' regardless of overflow.  */
> +  curr_value->it_interval
> +    = valid_timeval32_to_timeval64 (curr_value_32.it_interval);
> +  curr_value->it_value
> +    = valid_timeval32_to_timeval64 (curr_value_32.it_value);
> +  return 0;
> +#endif
> +}
> +
> +#if __TIMESIZE != 64
> +libc_hidden_def (__getitimer64)
> +int
> +__getitimer (__itimer_which_t which, struct itimerval *curr_value)
> +{
> +  struct __itimerval64 val64;
> +
> +  val64.it_interval
> +    = valid_timeval_to_timeval64 (curr_value->it_interval);
> +  val64.it_value
> +    = valid_timeval_to_timeval64 (curr_value->it_value);
> +
> +  return __getitimer64 (which, &val64);
> +}
> +#endif
> +weak_alias (__getitimer, getitimer)
> diff --git a/sysdeps/unix/sysv/linux/setitimer.c
> b/sysdeps/unix/sysv/linux/setitimer.c new file mode 100644
> index 0000000000..238853dd33
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/setitimer.c
> @@ -0,0 +1,95 @@
> +/* setitimer -- Set the state of an interval timer.  Linux/tv32
> version.
> +   Copyright (C) 2020 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
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <time.h>
> +#include <sys/time.h>
> +#include <sys/types.h>
> +#include <sysdep.h>
> +#include <tv32-compat.h>
> +
> +int
> +__setitimer64 (__itimer_which_t which,
> +               const struct __itimerval64 *restrict new_value,
> +               struct __itimerval64 *restrict old_value)
> +{
> +#if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
> +  return INLINE_SYSCALL_CALL (setitimer, which, new_value,
> old_value); +#else
> +  struct __itimerval32 new_value_32;
> +
> +  if (! in_time_t_range (new_value->it_interval.tv_sec))
> +  {
> +    __set_errno (EOVERFLOW);
> +    return -1;
> +  }
> +  new_value_32.it_interval
> +    = valid_timeval64_to_timeval32 (new_value->it_interval);
> +
> +  if (! in_time_t_range (new_value->it_value.tv_sec))
> +  {
> +    __set_errno (EOVERFLOW);
> +    return -1;
> +  }
> +  new_value_32.it_value
> +    = valid_timeval64_to_timeval32 (new_value->it_value);
> +
> +  if (old_value == NULL)
> +    return INLINE_SYSCALL_CALL (setitimer, which, &new_value_32,
> NULL); +
> +  struct __itimerval32 old_value_32;
> +  if (INLINE_SYSCALL_CALL (setitimer, which, &new_value_32,
> &old_value_32) == -1)
> +    return -1;
> +
> +  /* Write all fields of 'old_value' regardless of overflow.  */
> +  old_value->it_interval
> +     = valid_timeval32_to_timeval64 (old_value_32.it_interval);
> +  old_value->it_value
> +     = valid_timeval32_to_timeval64 (old_value_32.it_value);
> +  return 0;
> +#endif
> +}
> +
> +#if __TIMESIZE != 64
> +libc_hidden_def (__setitimer64)
> +int
> +__setitimer (__itimer_which_t which,
> +             const struct itimerval *restrict new_value,
> +             struct itimerval *restrict old_value)
> +{
> +  int ret;
> +  struct __itimerval64 new64, old64;
> +
> +  new64.it_interval
> +    = valid_timeval_to_timeval64 (new_value->it_interval);
> +  new64.it_value
> +    = valid_timeval_to_timeval64 (new_value->it_value);
> +
> +  ret = __setitimer64 (which, &new64, old_value ? &old64 : NULL);
> +
> +  if (ret == 0 && old_value)
> +    {
> +      old_value->it_interval
> +        = valid_timeval64_to_timeval (old64.it_interval);
> +      old_value->it_value
> +        = valid_timeval64_to_timeval (old64.it_value);
> +    }
> +
> +  return ret;
> +}
> +#endif
> +weak_alias (__setitimer, setitimer)
> diff --git a/sysdeps/unix/sysv/linux/tv32-compat.h
> b/sysdeps/unix/sysv/linux/tv32-compat.h new file mode 100644
> index 0000000000..b8791b1db8
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tv32-compat.h
> @@ -0,0 +1,31 @@
> +/* Compatibility definitions for `struct timeval' with 32-bit time_t.
> +   Copyright (C) 2020 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
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#ifndef _TV32_COMPAT_H
> +#define _TV32_COMPAT_H 1
> +
> +#include <bits/types/time_t.h>
> +
> +/* Structures containing 'struct timeval' with 32-bit time_t.  */
> +struct __itimerval32
> +{
> +  struct __timeval32 it_interval;
> +  struct __timeval32 it_value;
> +};
> +
> +#endif /* tv32-compat.h */

Tested-by: Lukasz Majewski <lukma@denx.de>

ARM32 (armv7) with QEMU:
https://github.com/lmajewski/meta-y2038/blob/master/README

Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

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