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


On Fri, Sep 13, 2019 at 7:36 AM Lukasz Majewski <lukma@denx.de> wrote:
>
> Hi Alistair,
>
> > 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, have you managed to make your patches working on top of this
> series?

Hey Lukasz,

I have been travelling recently and haven't had a chance to look at
fixing this (besides the diff I provided already).

I should be able to look at it this week.

Alistair

>
>
> >
> > 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
>
>
>
> 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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