[RFC 03/10] y2038: Convert __lll_futex* functions to use futex_time64 when available
Lukasz Majewski
lukma@denx.de
Sun Jul 12 13:43:10 GMT 2020
Dear Community,
> As the 'futex' syscall is wrapped with a C preprocessor macros, it was
> necessary to provide new set of those to replace call it with Y2038
> safe 'futex_time64' syscall.
>
> The current code expand wrapper's arguments as __VA_ARGS__ when more
> than three arguments are passed. For the conversion it was necessary
> to also have 'timeout' explicitly passed, and hence the introduction
> of lll_futex_syscall_time64_4 and lll_futex_syscall_time64 functions.
> The former expects exactly 4 arguments - timeout is the last one.
>
Comments are more than welcome.
> Signed-off-by: Lukasz Majewski <lukma@denx.de>
> ---
> sysdeps/nptl/lowlevellock-futex.h | 80
> ++++++++++++++++++++++++++++--- sysdeps/nptl/lowlevellock.h |
> 2 +- 2 files changed, 75 insertions(+), 7 deletions(-)
>
> diff --git a/sysdeps/nptl/lowlevellock-futex.h
> b/sysdeps/nptl/lowlevellock-futex.h index 2209ca76a1..a686773db4
> 100644 --- a/sysdeps/nptl/lowlevellock-futex.h
> +++ b/sysdeps/nptl/lowlevellock-futex.h
> @@ -65,14 +65,82 @@
> (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
> # endif
>
> -# define lll_futex_syscall(nargs, futexp, op, ...)
> \ +# define __lll_futex_syscall(nargs, futexp, op, ...)
> \ ({
> \
> - long int __ret = INTERNAL_SYSCALL (futex, nargs, futexp, op,
> \
> + long int __ret = INTERNAL_SYSCALL (futex, nargs, futexp, op,
> \ __VA_ARGS__); \
> (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret))
> \ ? -INTERNAL_SYSCALL_ERRNO (__ret) : 0);
> \ })
>
> +# define __lll_futex_syscall64(nargs, futexp, op, ...) \
> + ({
> \
> + long int __ret = INTERNAL_SYSCALL (futex_time64, nargs, futexp,
> op, \
> + __VA_ARGS__);
> \
> + (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret))
> \
> + ? -INTERNAL_SYSCALL_ERRNO (__ret) : 0);
> \
> + })
> +
> +# ifdef __ASSUME_TIME64_SYSCALLS
> +# ifndef __NR_futex_time64
> +# define __NR_futex_time64 __NR_futex
> +# endif
> +# define lll_futex_syscall(nargs, futexp, op, ...)
> \
> + __lll_futex_syscall64(nargs, futexp, op, __VA_ARGS__)
> +# define lll_futex_syscall_time64_4(nargs, futexp, op, val,
> timeout)\
> + __lll_futex_syscall64(nargs, futexp, op, val, timeout)
> +# define lll_futex_syscall_time64(nargs, futexp, op, val, timeout,
> ...)\
> + __lll_futex_syscall64(nargs, futexp, op, val, timeout, __VA_ARGS__)
> +# else
> +inline static long int
> +__lll_futex_syscall_time_check (long int __ret, const struct
> __timespec64 *t) +{
> + if (! (__ret == 0 || errno != ENOSYS))
> + if (t != NULL && ! in_time_t_range (t->tv_sec))
> + __ret = ({ errno = (EOVERFLOW); -1l; });
> + return __ret;
> +}
> +# define lll_futex_syscall(nargs, futexp, op, ...)
> \
> + ({
> \
> + long int __ret =
> \
> + __lll_futex_syscall64(nargs, futexp, op, __VA_ARGS__); \
> + if (! (__ret == 0 || errno != ENOSYS))
> \
> + __ret =
> \
> + __lll_futex_syscall(nargs, futexp, op, __VA_ARGS__); \
> + __ret;
> \
> + })
> +
> +# define lll_futex_syscall_time64(nargs, futexp, op, val, timeout,
> ...)\
> + ({
> \
> + struct timespec __ts32;
> \
> + if (timeout != NULL)
> \
> + __ts32 = valid_timespec64_to_timespec (*((struct
> __timespec64*) timeout)); \
> + long int __ret =
> \
> + __lll_futex_syscall64(nargs, futexp, op, val, timeout,\
> + __VA_ARGS__);
> \
> + __ret = __lll_futex_syscall_time_check (__ret, timeout);
> \
> + if (__ret != 0)
> \
> + __ret = __lll_futex_syscall(nargs, futexp, op, val, \
> + timeout != NULL ? &__ts32 : NULL,
> \
> + __VA_ARGS__);
> \
> + __ret;
> \
> + })
> +
> +# define lll_futex_syscall_time64_4(nargs, futexp, op, val,
> timeout)\
> + ({
> \
> + struct timespec __ts32;
> \
> + if (timeout != NULL)
> \
> + __ts32 = valid_timespec64_to_timespec (*((struct
> __timespec64*) timeout)); \
> + long int __ret =
> \
> + __lll_futex_syscall64(nargs, futexp, op, val, timeout);
> \
> + __ret = __lll_futex_syscall_time_check (__ret, timeout);
> \
> + if (__ret != 0)
> \
> + __ret = __lll_futex_syscall(nargs, futexp, op, val,
> \
> + timeout != NULL ? &__ts32 :
> NULL); \
> + __ret;
> \
> + })
> +
> +# endif
> /* For most of these macros, the return value is never really used.
> Nevertheless, the protocol is that each one returns a negated
> errno code for failure or zero for success. (Note that the
> corresponding @@ -85,7 +153,7 @@
> lll_futex_timed_wait (futexp, val, NULL, private)
>
> # define lll_futex_timed_wait(futexp, val, timeout, private) \
> - lll_futex_syscall (4, futexp, \
> + lll_futex_syscall_time64_4 (4, futexp,
> \ __lll_private_flag (FUTEX_WAIT, private), \
> val, timeout)
>
> @@ -107,7 +175,7 @@
> const int op =
> \ __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, private); \
> \
> - __ret = lll_futex_syscall (6, futexp, op, val,
> \
> + __ret = lll_futex_syscall_time64 (6, futexp, op, val,
> \ timeout, NULL /* Unused. */, \
> FUTEX_BITSET_MATCH_ANY);
> \ }
> \ @@ -118,7 +186,7 @@
>
> /* Wake up up to NR waiters on FUTEXP. */
> # define lll_futex_wake(futexp, nr, private)
> \
> - lll_futex_syscall (4, futexp,
> \
> + lll_futex_syscall_time64_4 (4, futexp,
> \ __lll_private_flag (FUTEX_WAKE, private), nr, 0)
>
> /* Wake up up to NR_WAKE waiters on FUTEXP. Move up to NR_MOVE of
> the @@ -159,7 +227,7 @@
> /* Like lll_futex_wait_requeue_pi, but with a timeout. */
> # define lll_futex_timed_wait_requeue_pi(futexp, val, timeout,
> clockbit, \ mutex, private) \
> - lll_futex_syscall (5, futexp,
> \
> + lll_futex_syscall_time64 (5, futexp,
> \ __lll_private_flag (FUTEX_WAIT_REQUEUE_PI \
> | (clockbit), private),
> \ val, timeout, mutex)
> diff --git a/sysdeps/nptl/lowlevellock.h b/sysdeps/nptl/lowlevellock.h
> index 68b3be8819..864152e609 100644
> --- a/sysdeps/nptl/lowlevellock.h
> +++ b/sysdeps/nptl/lowlevellock.h
> @@ -123,7 +123,7 @@ extern void __lll_lock_wait (int *futex, int
> private) attribute_hidden;
>
> extern int __lll_clocklock_wait (int *futex, int val, clockid_t,
> - const struct timespec *,
> + const struct __timespec64 *,
> int private) attribute_hidden;
>
> #define lll_timedwait(futex, val, clockid, abstime, private)
> \
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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