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Re: [PATCH v7 0/3] y2038: Linux: Introduce __clock_settime64 function


On Fri, Sep 6, 2019 at 2:55 PM Lukasz Majewski <lukma@denx.de> wrote:
>
> Hi Alistair,
>
> > On Fri, Sep 6, 2019 at 7:59 AM Lukasz Majewski <lukma@denx.de> wrote:
> > >
> > > This patch set introduces the conversion of clock_settime to
> > > explicit 64 bit struct __timespec64 arguments. As a result this
> > > function is now Y2038 safe.
> > >
> > > This work is (loosely) based on a previous development/patches:
> > > https://libc-alpha.sourceware.narkive.com/zniMOWui/rfc-patch-00-52-make-glibc-y2038-proof#post68
> > >
> > > Github branch (including the y2038 conversion example):
> > > https://github.com/lmajewski/y2038_glibc/commits/glibc__clock_settime-conversion-v7
> > >
> > > Those patches have been applied on top of master branch:
> > > SHA1: a26918cfda4bc4b9dad8aae1496e3ef7cbb63d96
> > >
> > > Shall be used with provided meta-y2038 for development and testing:
> > > https://github.com/lmajewski/meta-y2038
> > >
> > > I've used guidelines from:
> > > https://www.gnu.org/software/libc/manual/html_mono/libc.html
> > > "D.2.1 64-bit time symbol handling in the GNU C Library"
> > > to convert *clock_settime*.
> > >
> > > and most notably from:
> > > https://sourceware.org/glibc/wiki/Y2038ProofnessDesign#clock_gettime.28.29
> > >
> >
> > Thanks for the patches Lukassz!
> >
> > With my RV32 port I see this failure when compiling:
> >
>
> But I did not change the core code between v5 (to which you refer here):
> https://patchwork.ozlabs.org/cover/1155397/
> and then:
> https://sourceware.org/ml/libc-alpha/2019-05/msg00661.html
>
> and v7:
> https://patchwork.ozlabs.org/patch/1159056/
>
> (The only change in v6 was to use 32 bit call to clock_settime syscall
> as requested by Arnd to facilitate validation on existing systems.
> However, Joseph was against this change).
>
> The notable change (but not in this patch set) was moving clock_settime
> symbol solely to glibc (and it has been removed from librt).
>

Yes, I have had this issue for awhile.

> > In file included from ../sysdeps/generic/hp-timing.h:23,
> >                  from ../nptl/descr.h:27,
> >                  from ../sysdeps/riscv/nptl/tls.h:41,
> >                  from ../include/errno.h:25,
> >                  from ../sysdeps/unix/sysv/linux/clock_settime.c:18:
> > ../include/time.h:129:28: error: conflicting types for
> > '__clock_settime' # define __clock_settime64 __clock_settime
> >                             ^~~~~~~~~~~~~~~
> > ../sysdeps/unix/sysv/linux/clock_settime.c:25:1: note: in expansion of
> > macro '__clock_settime64'
> >  __clock_settime64 (clockid_t clock_id, const struct __timespec64 *tp)
> >  ^~~~~~~~~~~~~~~~~
> > In file included from <command-line>:
> > ../include/time.h:25:20: note: previous declaration of
> > '__clock_settime' was here
> >  libc_hidden_proto (__clock_settime)
> >                     ^~~~~~~~~~~~~~~
> > ./../include/libc-symbols.h:598:33: note: in definition of macro
> > '__hidden_proto'
> >    extern thread __typeof (name) name __hidden_proto_hiddenattr
> > (attrs); ^~~~
> > ./../include/libc-symbols.h:617:44: note: in expansion of macro
> > 'hidden_proto' # define libc_hidden_proto(name, attrs...)
> > hidden_proto (name, ##attrs) ^~~~~~~~~~~~
> > ../include/time.h:25:1: note: in expansion of macro
> > 'libc_hidden_proto' libc_hidden_proto (__clock_settime)
> >  ^~~~~~~~~~~~~~~~~
> > ../sysdeps/unix/sysv/linux/clock_settime.c:70:42: error: conflicting
> > types for 'clock_settime'
> >  versioned_symbol (libc, __clock_settime, clock_settime, GLIBC_2_17);
> >                                           ^~~~~~~~~~~~~
> > ./../include/libc-symbols.h:152:26: note: in definition of macro
> > '_weak_alias' extern __typeof (name) aliasname __attribute__ ((weak,
> > alias (#name))) \ ^~~~~~~~~
> > ../include/shlib-compat.h:74:3: note: in expansion of macro
> > 'weak_alias' weak_alias (local, symbol)
> >    ^~~~~~~~~~
> > ../sysdeps/unix/sysv/linux/clock_settime.c:70:1: note: in expansion of
> > macro 'versioned_symbol'
> >  versioned_symbol (libc, __clock_settime, clock_settime, GLIBC_2_17);
> >  ^~~~~~~~~~~~~~~~
> > In file included from ../include/time.h:2,
> >                  from ../sysdeps/generic/hp-timing.h:23,
> >                  from ../nptl/descr.h:27,
> >                  from ../sysdeps/riscv/nptl/tls.h:41,
> >                  from ../include/errno.h:25,
> >                  from ../sysdeps/unix/sysv/linux/clock_settime.c:18:
> > ../time/time.h:222:12: note: previous declaration of 'clock_settime'
> > was here extern int clock_settime (clockid_t __clock_id, const struct
> > timespec *__tp)
> >
> > Which I can fix with this diff:
> >
> > diff --git a/include/time.h b/include/time.h
> > index 7ed3aa61d1d..28e2722de21 100644
> > --- a/include/time.h
> > +++ b/include/time.h
> > @@ -125,13 +125,9 @@ extern __time64_t __timegm64 (struct tm *__tp)
> > __THROW; libc_hidden_proto (__timegm64)
> >  #endif
> >
> > -#if __TIMESIZE == 64
>
> What is the value of __TIMESIZE on your port? Is it 32 or 64 ?

It's 64.

>
> Do you also #define __USE_TIME_BITS64   1 ?

I don't. I can try with that, but I don't see if defined in the source.

Alistair

>
> > -# define __clock_settime64 __clock_settime
> > -#else
> >  extern int __clock_settime64 (clockid_t clock_id,
> >                                const struct __timespec64 *tp);
> >  libc_hidden_proto (__clock_settime64)
> > -#endif
> >
> >  /* Compute the `struct tm' representation of T,
> >     offset OFFSET seconds east of UTC,
> > diff --git a/sysdeps/unix/sysv/linux/clock_settime.c
> > b/sysdeps/unix/sysv/linux/clock_settime.c
> > index f5e084238a5..ab033c56ea9 100644
> > --- a/sysdeps/unix/sysv/linux/clock_settime.c
> > +++ b/sysdeps/unix/sysv/linux/clock_settime.c
> > @@ -54,7 +54,6 @@ __clock_settime64 (clockid_t clock_id, const struct
> > __timespec64 *tp)
> >  #endif
> >  }
> >
> > -#if __TIMESIZE != 64
>
> When I look on RISC-V patchset:
> https://patchwork.ozlabs.org/patch/1155391/
>
> for the __clock_nanosleep for example you follow the same convention.
> And you don't need to remove #if __TIMESIZE != 64 for example.
>
> One difference is that the clock_settime64 code will be Y2038 on e.g.
> 32 bit ARM only when I apply on top of it following patch:
> https://github.com/lmajewski/y2038_glibc/commit/c6740c05ea9b224a552847d10402f98da8376994
>
> (it enables redirect for clock_settime and support for -D_TIME_BITS=64
> compilation flag).
>
>
>
> >  int
> >  __clock_settime (clockid_t clock_id, const struct timespec *tp)
> >  {
> > @@ -63,7 +62,6 @@ __clock_settime (clockid_t clock_id, const struct
> > timespec *tp)
> >    valid_timespec_to_timespec64 (tp, &ts64);
> >    return __clock_settime64 (clock_id, &ts64);
> >  }
> > -#endif
> >
> >  libc_hidden_def (__clock_settime)
> >
> > Alistair
> >
> > >
> > >
> > > Lukasz Majewski (3):
> > >   y2038: Introduce internal for glibc struct __timespec64
> > >   y2038: Provide conversion helpers for struct __timespec64
> > >   y2038: linux: Provide __clock_settime64 implementation
> > >
> > >  include/time.h                          | 116
> > > ++++++++++++++++++++++++ sysdeps/unix/sysv/linux/clock_settime.c |
> > > 38 +++++++- 2 files changed, 150 insertions(+), 4 deletions(-)
> > >
> > > --
> > > 2.20.1
> > >
>
>
>
> 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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