[LTP] [PATCH v4 1/3] Add TST_THREAD_STATE_WAIT macro

[Cyril Hrubis]

Hi!
> The TST_THREAD_STATE_WAIT macro can be used to wait and check for
> pthread state changes.
> 
> Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.de>
> ---
>  include/tst_test.h         |  1 +
>  include/tst_thread_state.h | 33 +++++++++++++++++++++++++++++++++
>  lib/tst_thread_state.c     | 37 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 71 insertions(+)
>  create mode 100644 include/tst_thread_state.h
>  create mode 100644 lib/tst_thread_state.c
> 
> diff --git a/include/tst_test.h b/include/tst_test.h
> index 450ddf086..79067f3bf 100644
> --- a/include/tst_test.h
> +++ b/include/tst_test.h
> @@ -27,6 +27,7 @@
>  #include "tst_cmd.h"
>  #include "tst_cpu.h"
>  #include "tst_process_state.h"
> +#include "tst_thread_state.h"
>  #include "tst_atomic.h"
>  #include "tst_kvercmp.h"
>  #include "tst_kernel.h"
> diff --git a/include/tst_thread_state.h b/include/tst_thread_state.h
> new file mode 100644
> index 000000000..4d6a345b8
> --- /dev/null
> +++ b/include/tst_thread_state.h
> @@ -0,0 +1,33 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2022 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
> + */
> +
> +/*
> + * These functions helps you wait till a thread with given tpid changes state.
> + */
> +
> +#ifndef TST_THREAD_STATE__
> +#define TST_THREAD_STATE__
> +
> +#include <unistd.h>
> +
> +/*
> + * Waits for thread state change.
> + *
> + * The state is one of the following:
> + *
> + * R - running
> + * S - sleeping
> + * D - disk sleep
> + * T - stopped
> + * t - tracing stopped
> + * Z - zombie
> + * X - dead
> + */
> +#define TST_THREAD_STATE_WAIT(tid, state, msec_timeout) \
> +	tst_thread_state_wait((tid), (state), (msec_timeout))
> +
> +int tst_thread_state_wait(pid_t tid, const char state, unsigned int msec_timeout);
> +
> +#endif /* TST_THREAD_STATE__ */
> diff --git a/lib/tst_thread_state.c b/lib/tst_thread_state.c
> new file mode 100644
> index 000000000..f5580c39e
> --- /dev/null
> +++ b/lib/tst_thread_state.c
> @@ -0,0 +1,37 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2022 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
> + */
> +
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <string.h>
> +#include <errno.h>
> +
> +#include "tst_safe_file_ops.h"
> +#include "tst_thread_state.h"
> +
> +int tst_thread_state_wait(pid_t tid, const char state, unsigned int msec_timeout)
> +{
> +	char proc_path[128], cur_state;
> +	unsigned int msecs = 0;
> +
> +	snprintf(proc_path, sizeof(proc_path), "/proc/self/task/%i/stat", tid);
> +
> +	for (;;) {
> +		SAFE_FILE_SCANF(proc_path, "%*i %*s %c", &cur_state);
> +
> +		if (state == cur_state)
> +			break;
> +
> +		usleep(1000);
> +		msecs += 1;
> +
> +		if (msec_timeout && msecs >= msec_timeout) {
> +			errno = ETIMEDOUT;
> +			return -1;
> +		}
> +	}
> +
> +	return 0;
> +}

Maybe we can just put this code into the existing tst_process_state.h
header and C source.

And we should add some documentaion about the function into the
doc/c-test-api.txt as well.

Other than that it looks good.

-- 
Cyril Hrubis
chrubis@suse.cz