[4/6] linux: Use 32-bit time_t for itimerval

  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.

This means that all 32-bit architectures with a 64-bit time_t will be
able to use this generic implementation.

This code is based on similar code in alpha, but adjusted to pass the
32-bit time_t to the kernel.

We can't directly call the __getitimer/__setitimer functions as they
expect a struct itimerval but we need to pass in a struct itimerval32.
---
 include/time.h                                | 12 +++
 .../linux/generic/wordsize-32/getitimer.c     | 54 +++++++++++++
 .../linux/generic/wordsize-32/setitimer.c     | 77 +++++++++++++++++++
 .../linux/generic/wordsize-32/tv32-compat.h   | 35 +++++++++
 4 files changed, 178 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
 create mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
 create mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
  

Hi Alistair,

Maybe it would be good to rewrite the subject line to also reflect the
introduction of __[gs]etitimer64 ?

> 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.
> 
> This means that all 32-bit architectures with a 64-bit time_t will be
> able to use this generic implementation.
> 
> This code is based on similar code in alpha, but adjusted to pass the
> 32-bit time_t to the kernel.
> 
> We can't directly call the __getitimer/__setitimer functions as they
> expect a struct itimerval but we need to pass in a struct itimerval32.

Please update this patch series to also include information about
build/run testing.

For example:

Build-tests:
./src/scripts/build-many-glibcs.py glibcs


> ---
>  include/time.h                                | 12 +++
>  .../linux/generic/wordsize-32/getitimer.c     | 54 +++++++++++++
>  .../linux/generic/wordsize-32/setitimer.c     | 77
> +++++++++++++++++++ .../linux/generic/wordsize-32/tv32-compat.h   |
> 35 +++++++++ 4 files changed, 178 insertions(+)
>  create mode 100644
> sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c create mode

The same issue as pointed out in patch 6/6. The path
sysdeps/unix/sysv/linux/generic/wordsize-32 is NOT searched by ARMv7
(ARM32) for files to be built.

I've removed getitimer, getrusage and setitimer from
./sysdeps/unix/syscalls.list, so they are NOT auto generated wrappers
anymore, but this doesn't help.

It seems like for RV32 some extra paths are added...

I've dug to the @sysnames@ variable set in configure in the source of glibc.
I'm wondering how RV32 modifies it (and how it differs from ARM32)?


> 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c create
> mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
> 
> diff --git a/include/time.h b/include/time.h
> index 898ff0fb2d..e1d80b4190 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>
>  
> @@ -118,6 +119,17 @@ struct __itimerval64
>  };
>  #endif
>  
> +#if __TIMESIZE == 64
> +# define __getitimer64 __getitimer
> +# define __setitimer64 __setitimer
> +#else
> +extern int __getitimer64 (enum __itimer_which __which,
> +                          struct __itimerval64 *__value);

Please add here:
libc_hidden_proto (__getitimer64)

> +extern int __setitimer64 (enum __itimer_which __which,
> +                          const struct __itimerval64 *__restrict
> __new,
> +                          struct __itimerval64 *__restrict __old);

Please add here:
libc_hidden_proto (__setitimer64)

> +#endif
> +
>  #if __TIMESIZE == 64
>  # define __ctime64 ctime
>  #else
> diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
> b/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c new file
> mode 100644 index 0000000000..28a3e31126
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
> @@ -0,0 +1,54 @@
> +/* 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 <sysdep.h>
> +#include <tv32-compat.h>
> +
> +int
> +__getitimer64 (__itimer_which_t which, struct __itimerval64
> *curr_value) +{
> +  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;
> +}
> +
> +
> +#if __TIMESIZE != 64

Please add here:
libc_hidden_def (__gettimer64)

Rationale:

Before we introduce the Y2038 support (with -D_TIME_BITS=64) the
__gettimer64 shall be hidden (to avoid resolving it via PLT).

> +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);
> +}

Ok. As we expect 32 bit values - there is no need for checking (and 64
<-> 32 conversions will be OK).

> +#endif
> +weak_alias (__getitimer, getitimer)
> diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
> b/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c new file
> mode 100644 index 0000000000..fabc7f2c0c
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
> @@ -0,0 +1,77 @@
> +/* 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 <sysdep.h>
> +#include <tv32-compat.h>
> +
> +int
> +__setitimer64 (__itimer_which_t which,
> +               const struct __itimerval64 *restrict new_value,
> +               struct __itimerval64 *restrict old_value)
> +{
> +  struct __itimerval32 new_value_32;
> +  new_value_32.it_interval
> +    = valid_timeval64_to_timeval32 (new_value->it_interval);
> +  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); +

The above code is correct of course.

However, I've used another approach for timerfd_settime (IMHO a bit
more concise):
https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/timerfd_settime.c;h=164b4e860acb6a365a3890f30e2eac364a518c22;hb=eae22432723b877354291aca4dbbfde5891dad59#l49

> +  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;
> +}
> +
> +#if __TIMESIZE != 64

Please add here:
libc_hidden_def (__settimer64)

> +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, &old64);

I think that here we shall also consider the NULL pointer for old_value
(as stated in http://man7.org/linux/man-pages/man2/setitimer.2.html)

ret = __setitimer64 (which, &new64, old_value ? &old64 : NULL);

> +
> +  if (ret != 0)
> +    return ret;
> +
> +  old_value->it_interval
> +    = valid_timeval64_to_timeval (old64.it_interval);
> +  old_value->it_value
> +    = valid_timeval64_to_timeval (old64.it_value);
> +

Maybe it would be better to change this code to:

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

Please find the timerfd_settime as a reference:
https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/timerfd_settime.c;h=164b4e860acb6a365a3890f30e2eac364a518c22;hb=eae22432723b877354291aca4dbbfde5891dad59#l77

> +  return ret;
> +}
> +#endif
> +weak_alias (__setitimer, setitimer)
> diff --git
> a/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
> b/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h new file
> mode 100644 index 0000000000..4eb6f216ea --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
> @@ -0,0 +1,35 @@
> +/* 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 <features.h>
> +
> +#include <bits/types.h>
> +#include <bits/types/time_t.h>
> +#include <bits/types/struct_timeval.h>
> +
> +/* Structures containing 'struct timeval' with 32-bit time_t.  */
> +struct __itimerval32
> +{
> +  struct __timeval32 it_interval;
> +  struct __timeval32 it_value;
> +};

I do guess that here (with the introduction of tv32-compat.h) we do
follow what is done for alpha port?

> +
> +#endif /* tv32-compat.h */




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
  

On Feb 04 2020, Lukasz Majewski wrote:

> I've dug to the @sysnames@ variable set in configure in the source of glibc.
> I'm wondering how RV32 modifies it (and how it differs from ARM32)?

It is explicitly added through Implies (git grep -e wordsize-32 -- '*/Implies*')

Andreas.
  

Hi Andreas, Alistair,

> On Feb 04 2020, Lukasz Majewski wrote:
> 
> > I've dug to the @sysnames@ variable set in configure in the source
> > of glibc. I'm wondering how RV32 modifies it (and how it differs
> > from ARM32)?  
> 
> It is explicitly added through Implies (git grep -e wordsize-32 --
> '*/Implies*')

Thanks for pointing this out.

It seems like no riscv (rv32) sets this particular patch.

Only it is set for csky and nios2:
sysdeps/unix/sysv/linux/csky/Implies:unix/sysv/linux/generic/wordsize-32
sysdeps/unix/sysv/linux/nios2/Implies:unix/sysv/linux/generic/wordsize-32

However, it seems like I could:

1. Remove setitimer, getitimer, getrusage from
sysdeps/unix/syscalls.list

2. Extend Imply file for ARM32 (sysdeps/unix/sysv/linux/arm/Implies) by
adding
unix/sysv/linux/generic/wordsize-32

Unfortunately, this brings some issues with overflow header

../sysdeps/unix/sysv/linux/generic/wordsize-32/overflow.h:42:12: error:
'struct stat' has no member named '__st_ino_pad'; did you mean
'st_ino'? |    if (buf->__st_ino_pad == 0 && buf->__st_size_pad == 0 |
           ^~~~~~~~~~~~ |             st_ino
                                                                                                                                                                                                         

Maybe it would be better to not introduce setitimer, getitimer and
getrusage in:
sysdeps/unix/sysv/linux/generic/wordsize-32/

but instead in:
sysdeps/unix/sysv/linux/


So, it would be widely reusable as for example the __getitimer64 is
aliased anyway to getitimer for __TIMESIZE == 64 and __WORDSIZE==64 ?

(The same approach was taken with __timerfd_settime64 conversion:
https://sourceware.org/git/?p=glibc.git;a=commit;h=eae22432723b877354291aca4dbbfde5891dad59


> 
> Andreas.
> 




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
  

On Tue, Feb 4, 2020 at 6:49 AM Lukasz Majewski <lukma@denx.de> wrote:
>
> Hi Alistair,
>
> Maybe it would be good to rewrite the subject line to also reflect the
> introduction of __[gs]etitimer64 ?
>
> > 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.
> >
> > This means that all 32-bit architectures with a 64-bit time_t will be
> > able to use this generic implementation.
> >
> > This code is based on similar code in alpha, but adjusted to pass the
> > 32-bit time_t to the kernel.
> >
> > We can't directly call the __getitimer/__setitimer functions as they
> > expect a struct itimerval but we need to pass in a struct itimerval32.
>
> Please update this patch series to also include information about
> build/run testing.
>
> For example:
>
> Build-tests:
> ./src/scripts/build-many-glibcs.py glibcs

Sorry Lukasz, I somehow lost your response in my v2. I have updated my
v3 with your comments here.

>
>
> > ---
> >  include/time.h                                | 12 +++
> >  .../linux/generic/wordsize-32/getitimer.c     | 54 +++++++++++++
> >  .../linux/generic/wordsize-32/setitimer.c     | 77
> > +++++++++++++++++++ .../linux/generic/wordsize-32/tv32-compat.h   |
> > 35 +++++++++ 4 files changed, 178 insertions(+)
> >  create mode 100644
> > sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c create mode
>
> The same issue as pointed out in patch 6/6. The path
> sysdeps/unix/sysv/linux/generic/wordsize-32 is NOT searched by ARMv7
> (ARM32) for files to be built.
>
> I've removed getitimer, getrusage and setitimer from
> ./sysdeps/unix/syscalls.list, so they are NOT auto generated wrappers
> anymore, but this doesn't help.
>
> It seems like for RV32 some extra paths are added...
>
> I've dug to the @sysnames@ variable set in configure in the source of glibc.
> I'm wondering how RV32 modifies it (and how it differs from ARM32)?

This has been addressed in v2.

>
>
> > 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c create
> > mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
> >
> > diff --git a/include/time.h b/include/time.h
> > index 898ff0fb2d..e1d80b4190 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>
> >
> > @@ -118,6 +119,17 @@ struct __itimerval64
> >  };
> >  #endif
> >
> > +#if __TIMESIZE == 64
> > +# define __getitimer64 __getitimer
> > +# define __setitimer64 __setitimer
> > +#else
> > +extern int __getitimer64 (enum __itimer_which __which,
> > +                          struct __itimerval64 *__value);
>
> Please add here:
> libc_hidden_proto (__getitimer64)

Fixed in v3

>
> > +extern int __setitimer64 (enum __itimer_which __which,
> > +                          const struct __itimerval64 *__restrict
> > __new,
> > +                          struct __itimerval64 *__restrict __old);
>
> Please add here:
> libc_hidden_proto (__setitimer64)

Fixed in v3

>
> > +#endif
> > +
> >  #if __TIMESIZE == 64
> >  # define __ctime64 ctime
> >  #else
> > diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
> > b/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c new file
> > mode 100644 index 0000000000..28a3e31126
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
> > @@ -0,0 +1,54 @@
> > +/* 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 <sysdep.h>
> > +#include <tv32-compat.h>
> > +
> > +int
> > +__getitimer64 (__itimer_which_t which, struct __itimerval64
> > *curr_value) +{
> > +  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;
> > +}
> > +
> > +
> > +#if __TIMESIZE != 64
>
> Please add here:
> libc_hidden_def (__gettimer64)

Fixed in v3

>
> Rationale:
>
> Before we introduce the Y2038 support (with -D_TIME_BITS=64) the
> __gettimer64 shall be hidden (to avoid resolving it via PLT).
>
> > +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);
> > +}
>
> Ok. As we expect 32 bit values - there is no need for checking (and 64
> <-> 32 conversions will be OK).
>
> > +#endif
> > +weak_alias (__getitimer, getitimer)
> > diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
> > b/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c new file
> > mode 100644 index 0000000000..fabc7f2c0c
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
> > @@ -0,0 +1,77 @@
> > +/* 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 <sysdep.h>
> > +#include <tv32-compat.h>
> > +
> > +int
> > +__setitimer64 (__itimer_which_t which,
> > +               const struct __itimerval64 *restrict new_value,
> > +               struct __itimerval64 *restrict old_value)
> > +{
> > +  struct __itimerval32 new_value_32;
> > +  new_value_32.it_interval
> > +    = valid_timeval64_to_timeval32 (new_value->it_interval);
> > +  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); +
>
> The above code is correct of course.
>
> However, I've used another approach for timerfd_settime (IMHO a bit
> more concise):
> https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/timerfd_settime.c;h=164b4e860acb6a365a3890f30e2eac364a518c22;hb=eae22432723b877354291aca4dbbfde5891dad59#l49
>
> > +  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;
> > +}
> > +
> > +#if __TIMESIZE != 64
>
> Please add here:
> libc_hidden_def (__settimer64)

Fixed in v3

>
> > +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, &old64);
>
> I think that here we shall also consider the NULL pointer for old_value
> (as stated in http://man7.org/linux/man-pages/man2/setitimer.2.html)
>
> ret = __setitimer64 (which, &new64, old_value ? &old64 : NULL);
>
> > +
> > +  if (ret != 0)
> > +    return ret;
> > +
> > +  old_value->it_interval
> > +    = valid_timeval64_to_timeval (old64.it_interval);
> > +  old_value->it_value
> > +    = valid_timeval64_to_timeval (old64.it_value);
> > +
>
> Maybe it would be better to change this code to:
>
> 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

Fixed in v3

>
> Please find the timerfd_settime as a reference:
> https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/timerfd_settime.c;h=164b4e860acb6a365a3890f30e2eac364a518c22;hb=eae22432723b877354291aca4dbbfde5891dad59#l77
>
> > +  return ret;
> > +}
> > +#endif
> > +weak_alias (__setitimer, setitimer)
> > diff --git
> > a/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
> > b/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h new file
> > mode 100644 index 0000000000..4eb6f216ea --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
> > @@ -0,0 +1,35 @@
> > +/* 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 <features.h>
> > +
> > +#include <bits/types.h>
> > +#include <bits/types/time_t.h>
> > +#include <bits/types/struct_timeval.h>
> > +
> > +/* Structures containing 'struct timeval' with 32-bit time_t.  */
> > +struct __itimerval32
> > +{
> > +  struct __timeval32 it_interval;
> > +  struct __timeval32 it_value;
> > +};
>
> I do guess that here (with the introduction of tv32-compat.h) we do
> follow what is done for alpha port?

Alpha always uses a 32-bit value, while in the generic case we use a
long (so the wordsize).

Alistair

>
> > +
> > +#endif /* tv32-compat.h */
>
>
>
>
> 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
  

On Mon, 10 Feb 2020 09:56:40 -0800
Alistair Francis <alistair23@gmail.com> wrote:

> On Tue, Feb 4, 2020 at 6:49 AM Lukasz Majewski <lukma@denx.de> wrote:
> >
> > Hi Alistair,
> >
> > Maybe it would be good to rewrite the subject line to also reflect
> > the introduction of __[gs]etitimer64 ?
> >  
> > > 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.
> > >
> > > This means that all 32-bit architectures with a 64-bit time_t
> > > will be able to use this generic implementation.
> > >
> > > This code is based on similar code in alpha, but adjusted to pass
> > > the 32-bit time_t to the kernel.
> > >
> > > We can't directly call the __getitimer/__setitimer functions as
> > > they expect a struct itimerval but we need to pass in a struct
> > > itimerval32.  
> >
> > Please update this patch series to also include information about
> > build/run testing.
> >
> > For example:
> >
> > Build-tests:
> > ./src/scripts/build-many-glibcs.py glibcs  
> 
> Sorry Lukasz, I somehow lost your response in my v2. I have updated my
> v3 with your comments here.

Ok, I'm looking forward for v3 then :-).

Thanks for your patches.

> 
> >
> >  
> > > ---
> > >  include/time.h                                | 12 +++
> > >  .../linux/generic/wordsize-32/getitimer.c     | 54 +++++++++++++
> > >  .../linux/generic/wordsize-32/setitimer.c     | 77
> > > +++++++++++++++++++ .../linux/generic/wordsize-32/tv32-compat.h
> > > | 35 +++++++++ 4 files changed, 178 insertions(+)
> > >  create mode 100644
> > > sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c create
> > > mode  
> >
> > The same issue as pointed out in patch 6/6. The path
> > sysdeps/unix/sysv/linux/generic/wordsize-32 is NOT searched by ARMv7
> > (ARM32) for files to be built.
> >
> > I've removed getitimer, getrusage and setitimer from
> > ./sysdeps/unix/syscalls.list, so they are NOT auto generated
> > wrappers anymore, but this doesn't help.
> >
> > It seems like for RV32 some extra paths are added...
> >
> > I've dug to the @sysnames@ variable set in configure in the source
> > of glibc. I'm wondering how RV32 modifies it (and how it differs
> > from ARM32)?  
> 
> This has been addressed in v2.
> 
> >
> >  
> > > 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
> > > create mode 100644
> > > sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
> > >
> > > diff --git a/include/time.h b/include/time.h
> > > index 898ff0fb2d..e1d80b4190 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>
> > >
> > > @@ -118,6 +119,17 @@ struct __itimerval64
> > >  };
> > >  #endif
> > >
> > > +#if __TIMESIZE == 64
> > > +# define __getitimer64 __getitimer
> > > +# define __setitimer64 __setitimer
> > > +#else
> > > +extern int __getitimer64 (enum __itimer_which __which,
> > > +                          struct __itimerval64 *__value);  
> >
> > Please add here:
> > libc_hidden_proto (__getitimer64)  
> 
> Fixed in v3
> 
> >  
> > > +extern int __setitimer64 (enum __itimer_which __which,
> > > +                          const struct __itimerval64 *__restrict
> > > __new,
> > > +                          struct __itimerval64 *__restrict
> > > __old);  
> >
> > Please add here:
> > libc_hidden_proto (__setitimer64)  
> 
> Fixed in v3
> 
> >  
> > > +#endif
> > > +
> > >  #if __TIMESIZE == 64
> > >  # define __ctime64 ctime
> > >  #else
> > > diff --git
> > > a/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
> > > b/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c new
> > > file mode 100644 index 0000000000..28a3e31126 --- /dev/null
> > > +++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
> > > @@ -0,0 +1,54 @@
> > > +/* 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 <sysdep.h>
> > > +#include <tv32-compat.h>
> > > +
> > > +int
> > > +__getitimer64 (__itimer_which_t which, struct __itimerval64
> > > *curr_value) +{
> > > +  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;
> > > +}
> > > +
> > > +
> > > +#if __TIMESIZE != 64  
> >
> > Please add here:
> > libc_hidden_def (__gettimer64)  
> 
> Fixed in v3
> 
> >
> > Rationale:
> >
> > Before we introduce the Y2038 support (with -D_TIME_BITS=64) the
> > __gettimer64 shall be hidden (to avoid resolving it via PLT).
> >  
> > > +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);
> > > +}  
> >
> > Ok. As we expect 32 bit values - there is no need for checking (and
> > 64 <-> 32 conversions will be OK).
> >  
> > > +#endif
> > > +weak_alias (__getitimer, getitimer)
> > > diff --git
> > > a/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
> > > b/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c new
> > > file mode 100644 index 0000000000..fabc7f2c0c --- /dev/null
> > > +++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
> > > @@ -0,0 +1,77 @@
> > > +/* 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 <sysdep.h>
> > > +#include <tv32-compat.h>
> > > +
> > > +int
> > > +__setitimer64 (__itimer_which_t which,
> > > +               const struct __itimerval64 *restrict new_value,
> > > +               struct __itimerval64 *restrict old_value)
> > > +{
> > > +  struct __itimerval32 new_value_32;
> > > +  new_value_32.it_interval
> > > +    = valid_timeval64_to_timeval32 (new_value->it_interval);
> > > +  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); +  
> >
> > The above code is correct of course.
> >
> > However, I've used another approach for timerfd_settime (IMHO a bit
> > more concise):
> > https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/timerfd_settime.c;h=164b4e860acb6a365a3890f30e2eac364a518c22;hb=eae22432723b877354291aca4dbbfde5891dad59#l49
> >  
> > > +  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;
> > > +}
> > > +
> > > +#if __TIMESIZE != 64  
> >
> > Please add here:
> > libc_hidden_def (__settimer64)  
> 
> Fixed in v3
> 
> >  
> > > +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, &old64);  
> >
> > I think that here we shall also consider the NULL pointer for
> > old_value (as stated in
> > http://man7.org/linux/man-pages/man2/setitimer.2.html)
> >
> > ret = __setitimer64 (which, &new64, old_value ? &old64 : NULL);
> >  
> > > +
> > > +  if (ret != 0)
> > > +    return ret;
> > > +
> > > +  old_value->it_interval
> > > +    = valid_timeval64_to_timeval (old64.it_interval);
> > > +  old_value->it_value
> > > +    = valid_timeval64_to_timeval (old64.it_value);
> > > +  
> >
> > Maybe it would be better to change this code to:
> >
> > 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  
> 
> Fixed in v3
> 
> >
> > Please find the timerfd_settime as a reference:
> > https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/timerfd_settime.c;h=164b4e860acb6a365a3890f30e2eac364a518c22;hb=eae22432723b877354291aca4dbbfde5891dad59#l77
> >  
> > > +  return ret;
> > > +}
> > > +#endif
> > > +weak_alias (__setitimer, setitimer)
> > > diff --git
> > > a/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
> > > b/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h new
> > > file mode 100644 index 0000000000..4eb6f216ea --- /dev/null
> > > +++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
> > > @@ -0,0 +1,35 @@
> > > +/* 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 <features.h>
> > > +
> > > +#include <bits/types.h>
> > > +#include <bits/types/time_t.h>
> > > +#include <bits/types/struct_timeval.h>
> > > +
> > > +/* Structures containing 'struct timeval' with 32-bit time_t.  */
> > > +struct __itimerval32
> > > +{
> > > +  struct __timeval32 it_interval;
> > > +  struct __timeval32 it_value;
> > > +};  
> >
> > I do guess that here (with the introduction of tv32-compat.h) we do
> > follow what is done for alpha port?  
> 
> Alpha always uses a 32-bit value, while in the generic case we use a
> long (so the wordsize).
> 
> Alistair
> 
> >  
> > > +
> > > +#endif /* tv32-compat.h */  
> >
> >
> >
> >
> > 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  




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