Re: [PATCH v4 1/2] y2038: linux: Provide __timerfd_gettime64 implementation

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

On 06/01/2020 09:17, Lukasz Majewski wrote:
> This patch replaces auto generated wrapper (as described in
> sysdeps/unix/sysv/linux/syscalls.list) for timerfd_gettime with one which
> adds extra support for reading 64 bit time values on machines with
> __TIMESIZE != 64.
> There is no functional change for architectures already supporting 64 bit
> time ABI.
> 
> This patch is conceptually identical to timer_gettime conversion already
> done in sysdeps/unix/sysv/linux/timer_gettime.c.
> Please refer to corresponding commit message for detailed description of
> introduced functions and the testing procedure.
> 
> ---
> Changes for v4:
> - Update date from 2019 to 2020
> 
> Changes for v3:
> - Add missing libc_hidden_def()
> 
> Changes for v2:
> - Remove "Contributed by" from the file header
> - Remove early check for (fd < 0) in __timerfd_gettime64 as the fd
>   correctness check is already done in Linux kernel
> - Add single descriptive comment line to provide concise explanation
>   of the code

LGTM when 2.32 opens, thanks.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

> ---
>  include/time.h                            |  3 +
>  sysdeps/unix/sysv/linux/Makefile          |  3 +-
>  sysdeps/unix/sysv/linux/syscalls.list     |  1 -
>  sysdeps/unix/sysv/linux/timerfd_gettime.c | 68 +++++++++++++++++++++++
>  4 files changed, 73 insertions(+), 2 deletions(-)
>  create mode 100644 sysdeps/unix/sysv/linux/timerfd_gettime.c
> 
> diff --git a/include/time.h b/include/time.h
> index e5e8246eac..eb5082b4d7 100644
> --- a/include/time.h
> +++ b/include/time.h
> @@ -181,9 +181,12 @@ libc_hidden_proto (__futimens64);
>  
>  #if __TIMESIZE == 64
>  # define __timer_gettime64 __timer_gettime
> +# define __timerfd_gettime64 __timerfd_gettime
>  #else
>  extern int __timer_gettime64 (timer_t timerid, struct __itimerspec64 *value);
> +extern int __timerfd_gettime64 (int fd, struct __itimerspec64 *value);
>  libc_hidden_proto (__timer_gettime64);
> +libc_hidden_proto (__timerfd_gettime64);
>  #endif
>  
>  #if __TIMESIZE == 64

Ok.

> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index f12b7b1a2d..74923740b9 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -60,7 +60,8 @@ sysdep_routines += adjtimex clone umount umount2 readahead \
>  		   setfsuid setfsgid epoll_pwait signalfd \
>  		   eventfd eventfd_read eventfd_write prlimit \
>  		   personality epoll_wait tee vmsplice splice \
> -		   open_by_handle_at mlock2 pkey_mprotect pkey_set pkey_get
> +		   open_by_handle_at mlock2 pkey_mprotect pkey_set pkey_get \
> +		   timerfd_gettime
>  
>  CFLAGS-gethostid.c = -fexceptions
>  CFLAGS-tee.c = -fexceptions -fasynchronous-unwind-tables

Ok.

> diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
> index 5f1352ad43..adb9055ce2 100644
> --- a/sysdeps/unix/sysv/linux/syscalls.list
> +++ b/sysdeps/unix/sysv/linux/syscalls.list
> @@ -94,7 +94,6 @@ mq_setattr	-	mq_getsetattr	i:ipp	mq_setattr
>  
>  timerfd_create	EXTRA	timerfd_create	i:ii	timerfd_create
>  timerfd_settime	EXTRA	timerfd_settime	i:iipp	timerfd_settime
> -timerfd_gettime	EXTRA	timerfd_gettime	i:ip	timerfd_gettime
>  
>  fanotify_init	EXTRA	fanotify_init	i:ii	fanotify_init
>  

Ok.

> diff --git a/sysdeps/unix/sysv/linux/timerfd_gettime.c b/sysdeps/unix/sysv/linux/timerfd_gettime.c
> new file mode 100644
> index 0000000000..7d09eeb11a
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/timerfd_gettime.c
> @@ -0,0 +1,68 @@
> +/* timerfd_gettime -- get the timer setting referred to by file descriptor.
> +   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; see the file COPYING.LIB.  If
> +   not, see <https://www.gnu.org/licenses/>.  */
> +
> +#include <errno.h>
> +#include <stdlib.h>
> +#include <time.h>
> +#include <sysdep.h>
> +#include <kernel-features.h>
> +
> +int
> +__timerfd_gettime64 (int fd, struct __itimerspec64 *value)
> +{
> +#ifdef __ASSUME_TIME64_SYSCALLS
> +# ifndef __NR_timerfd_gettime64
> +#  define __NR_timerfd_gettime64 __NR_timerfd_gettime
> +# endif
> +  return INLINE_SYSCALL_CALL (timerfd_gettime64, fd, value);
> +#else
> +# ifdef __NR_timerfd_gettime64
> +  int ret = INLINE_SYSCALL_CALL (timerfd_gettime64, fd, value);
> +  if (ret == 0 || errno != ENOSYS)
> +    return ret;
> +# endif

Ok. 

As a side note, now that arch-syscall patch is upstream should we
assume that for !__ASSUME_TIME64_SYSCALLS the __NR_timerfd_gettime64
should be defined (meaning that Linux supports time64 for all 32-bit
architectures)?

> +  struct itimerspec its32;
> +  int retval = INLINE_SYSCALL_CALL (timerfd_gettime, fd, &its32);
> +  if (retval == 0)
> +    {
> +      value->it_interval = valid_timespec_to_timespec64 (its32.it_interval);
> +      value->it_value = valid_timespec_to_timespec64 (its32.it_value);
> +    }
> +
> +  return retval;
> +#endif
> +}


Ok.

> +
> +#if __TIMESIZE != 64
> +libc_hidden_def (__timerfd_gettime64)

Ok.

As a side note, we should fix it on clock_{get,set}time to add the missing
libc_hidden_def.

> +
> +int
> +__timerfd_gettime (int fd, struct itimerspec *value)
> +{
> +  struct __itimerspec64 its64;
> +  int retval = __timerfd_gettime64 (fd, &its64);
> +  if (retval == 0)
> +    {
> +      value->it_interval = valid_timespec64_to_timespec (its64.it_interval);
> +      value->it_value = valid_timespec64_to_timespec (its64.it_value);
> +    }
> +
> +  return retval;
> +}
> +#endif
> +strong_alias (__timerfd_gettime, timerfd_gettime)
> 

Ok.