Re: [PATCH 03/18] support: Add support_create_timer

[Lukasz Majewski <lukma@denx.de>]

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On Thu, 17 Jun 2021 08:50:49 -0300
Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:

> It is a simple wrapper over timer_create, timer_settime, and
> sigaction.  It will be used to check for large timeout to trigger an
> EINTR.
> ---
>  support/Makefile               |  1 +
>  support/support.h              | 11 ++++++
>  support/support_create_timer.c | 69
> ++++++++++++++++++++++++++++++++++ 3 files changed, 81 insertions(+)
>  create mode 100644 support/support_create_timer.c
> 
> diff --git a/support/Makefile b/support/Makefile
> index f3ebaa8d2e..278f4627d8 100644
> --- a/support/Makefile
> +++ b/support/Makefile
> @@ -50,6 +50,7 @@ libsupport-routines = \
>    support_chroot \
>    support_copy_file \
>    support_copy_file_range \
> +  support_create_timer \
>    support_descriptor_supports_holes \
>    support_descriptors \
>    support_enter_mount_namespace \
> diff --git a/support/support.h b/support/support.h
> index 874204b7fc..9ec8ecb8d7 100644
> --- a/support/support.h
> +++ b/support/support.h
> @@ -24,6 +24,7 @@
>  #define SUPPORT_H
>  
>  #include <stdbool.h>
> +#include <stdint.h>
>  #include <stddef.h>
>  #include <sys/cdefs.h>
>  /* For mode_t.  */
> @@ -153,6 +154,16 @@ extern bool support_select_modifies_timeout
> (void); tv_usec larger than 1000000.  */
>  extern bool support_select_normalizes_timeout (void);
>  
> +/* Create a timer that trigger after SEC seconds and NSEC
> nanoseconds.  If
> +   REPEAT is true the timer will repeat indefinitely.  If CALLBACK
> is not
> +   NULL, the function will be called when the timer expires;
> otherwise a
> +   dummy empty function is used instead.
> +   This is implemented with POSIX per-process timer with
> SIGEV_SIGNAL.  */ +timer_t support_create_timer (uint64_t sec, long
> int nsec, bool repeat,
> +			      void (*callback)(int));
> +/* Disable the timer TIMER.  */
> +void support_delete_timer (timer_t timer);
> +
>  __END_DECLS
>  
>  #endif /* SUPPORT_H */
> diff --git a/support/support_create_timer.c
> b/support/support_create_timer.c new file mode 100644
> index 0000000000..c93aaa5c6b
> --- /dev/null
> +++ b/support/support_create_timer.c
> @@ -0,0 +1,69 @@
> +/* Create a periodic timer.
> +   Copyright (C) 2021 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
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/xsignal.h>
> +#include <time.h>
> +
> +static void
> +dummy_alrm_handler (int sig)
> +{
> +}
> +
> +timer_t
> +support_create_timer (uint64_t sec, long int nsec, bool repeat,
> +		      void (*callback)(int))
> +{
> +  struct sigaction sa;
> +  sa.sa_handler = callback != NULL ? callback : dummy_alrm_handler;
> +  sigemptyset (&sa.sa_mask);
> +  sa.sa_flags = 0;
> +  xsigaction (SIGALRM, &sa, NULL);
> +
> +  struct sigevent ev = {
> +    .sigev_notify = SIGEV_SIGNAL,
> +    .sigev_signo = SIGALRM
> +  };
> +  timer_t timerid;
> +  int r = timer_create (CLOCK_REALTIME, &ev, &timerid);
> +  if (r == -1)
> +    FAIL_EXIT1 ("timer_create: %m");
> +
> +  /* Single timer with 0.1s.  */
> +  struct itimerspec its =
> +    {
> +      { .tv_sec = repeat ? sec : 0, .tv_nsec = repeat ? nsec : 0 },
> +      { .tv_sec = sec, .tv_nsec = nsec }
> +    };
> +  r = timer_settime (timerid, 0, &its, NULL);
> +  if (r == -1)
> +    FAIL_EXIT1 ("timer_settime: %m");
> +
> +  return timerid;
> +}
> +
> +/* Disable the timer TIMER.  */
> +void
> +support_delete_timer (timer_t timer)
> +{
> +  int r = timer_delete (timer);
> +  if (r == -1)
> +    FAIL_EXIT1 ("timer_delete: %m");
> +  xsignal (SIGALRM, SIG_DFL);
> +}

Reviewed-by: Lukasz Majewski <lukma@denx.de>


Best regards,

Lukasz Majewski

--

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