[LTP] [PATCH v4 1/2] syscalls/prctl08: New test for prctl() with PR_{SET, GET}_TIMERSLACK

[Yang Xu <xuyang2018.jy@cn.fujitsu.com>]

Hi Cyril
Ping.

> ------
> v3->v4:
> split it into two cases, prctl08 test read/set timer slack value and
> prctl09 is a timer samle test.
> Also, in prctl08, I split into 5 point(0,1,middle,max and inherit).
> -----
> 
> Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
> ---
>   include/lapi/prctl.h                       |   5 +
>   runtest/syscalls                           |   1 +
>   testcases/kernel/syscalls/prctl/.gitignore |   1 +
>   testcases/kernel/syscalls/prctl/prctl08.c  | 135 +++++++++++++++++++++
>   4 files changed, 142 insertions(+)
>   create mode 100644 testcases/kernel/syscalls/prctl/prctl08.c
> 
> diff --git a/include/lapi/prctl.h b/include/lapi/prctl.h
> index 8ee492259..0b4e196c3 100644
> --- a/include/lapi/prctl.h
> +++ b/include/lapi/prctl.h
> @@ -19,6 +19,11 @@
>   # define PR_SET_SECCOMP  22
>   #endif
>   
> +#ifndef PR_SET_TIMERSLACK
> +# define PR_SET_TIMERSLACK 29
> +# define PR_GET_TIMERSLACK 30
> +#endif
> +
>   #ifndef PR_SET_CHILD_SUBREAPER
>   # define PR_SET_CHILD_SUBREAPER	36
>   # define PR_GET_CHILD_SUBREAPER	37
> diff --git a/runtest/syscalls b/runtest/syscalls
> index 4e6310193..76961a684 100644
> --- a/runtest/syscalls
> +++ b/runtest/syscalls
> @@ -878,6 +878,7 @@ prctl04 prctl04
>   prctl05 prctl05
>   prctl06 prctl06
>   prctl07 prctl07
> +prctl08 prctl08
>   
>   pread01 pread01
>   pread01_64 pread01_64
> diff --git a/testcases/kernel/syscalls/prctl/.gitignore b/testcases/kernel/syscalls/prctl/.gitignore
> index 2178db366..fe36a8e0f 100644
> --- a/testcases/kernel/syscalls/prctl/.gitignore
> +++ b/testcases/kernel/syscalls/prctl/.gitignore
> @@ -6,3 +6,4 @@
>   /prctl06
>   /prctl06_execve
>   /prctl07
> +/prctl08
> diff --git a/testcases/kernel/syscalls/prctl/prctl08.c b/testcases/kernel/syscalls/prctl/prctl08.c
> new file mode 100644
> index 000000000..9aa15b06d
> --- /dev/null
> +++ b/testcases/kernel/syscalls/prctl/prctl08.c
> @@ -0,0 +1,135 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2019 FUJITSU LIMITED. All rights reserved.
> + * Author: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
> + *
> + * Test PR_GET_TIMERSLACK and PR_SET_TIMERSLACK of prctl(2).
> + * 1)Each thread has two associated timer slack values: a "default"
> + *   value, and a "current" value. PR_SET_TIMERSLACK sets the "current"
> + *   timer slack value for the calling thread.
> + * 2)When a new thread is created, the two timer slack values are made
> + *   the same as the "current" value of the creating thread.
> + * 3)The maximum timer slack value is ULONG_MAX. On 32bit machines, it
> + *   is a valid value(about 4s). On 64bit machines, it is about 500 years
> + *   and no person will set this over 4s.  prctl return value is int, so
> + *   we test themaximum value is INT_MAX.
> + * 4)we also check current value via /proc/self/timerslack_ns if it is
> + *  supported.
> + */
> +
> +#include <sys/prctl.h>
> +#include <string.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <linux/limits.h>
> +#include "lapi/syscalls.h"
> +#include "lapi/prctl.h"
> +#include "tst_test.h"
> +
> +#define PROC_TIMERSLACK_PATH "/proc/self/timerslack_ns"
> +
> +static void check_get_timerslack(char *message, unsigned long value);
> +static void check_inherit_timerslack(char *message, unsigned long value);
> +
> +static struct tcase {
> +	void (*func_check)();
> +	unsigned long setvalue;
> +	unsigned long expvalue;
> +	char message[50];
> +} tcases[] = {
> +	{check_get_timerslack, 0, 50000, "Reset"},
> +	{check_get_timerslack, 1, 1, "Min"},
> +	{check_get_timerslack, 70000, 70000, "Middle"},
> +	{check_get_timerslack, INT_MAX, INT_MAX, "Max"},
> +	{check_inherit_timerslack, 70000, 70000, "Child process"},
> +};
> +
> +static int proc_flag = 1;
> +
> +static void check_proc_timerslack(char *message, unsigned long value)
> +{
> +	unsigned long proc_value;
> +
> +	SAFE_FILE_SCANF(PROC_TIMERSLACK_PATH, "%lu", &proc_value);
> +	if (proc_value == value)
> +		tst_res(TPASS, "%s %s  got %lu expectedly",
> +				message, PROC_TIMERSLACK_PATH, proc_value);
> +	else
> +		tst_res(TFAIL, "%s %s expected %lu got %lu",
> +				message, PROC_TIMERSLACK_PATH, value, proc_value);
> +}
> +
> +static void check_get_timerslack(char *message, unsigned long value)
> +{
> +	TEST(prctl(PR_GET_TIMERSLACK));
> +	if ((unsigned long)TST_RET == value)
> +		tst_res(TPASS, "%s prctl(PR_GET_TIMERSLACK) got %lu expectedly",
> +				message, value);
> +	else
> +		tst_res(TFAIL, "%s prctl(PR_GET_TIMERSLACK) expected %lu got %lu",
> +				message, value, TST_RET);
> +
> +	if (proc_flag)
> +		check_proc_timerslack(message, value);
> +
> +}
> +
> +static void check_inherit_timerslack(char *message, unsigned long value)
> +{
> +	int pid;
> +	unsigned long current_value;
> +	unsigned long default_value;
> +
> +	pid = SAFE_FORK();
> +	if (pid == 0) {
> +		current_value = prctl(PR_GET_TIMERSLACK);
> +		prctl(PR_SET_TIMERSLACK, 0);
> +		default_value = prctl(PR_GET_TIMERSLACK);
> +		if (current_value == value && default_value == value)
> +			tst_res(TPASS,
> +				"%s two timer slack values are made the same as the current value(%lu) of the creating thread.",
> +				message, value);
> +		else
> +			tst_res(TFAIL,
> +				"%s current_value is %lu, default value is %lu, the parent current value is %lu",
> +				message, current_value, default_value, value);
> +	}
> +
> +}
> +
> +static void verify_prctl(unsigned int n)
> +{
> +	struct tcase *tc = &tcases[n];
> +
> +	TEST(prctl(PR_SET_TIMERSLACK, tc->setvalue));
> +	if (TST_RET == -1) {
> +		tst_res(TFAIL | TTERRNO, "prctl(PR_SET_TIMERSLACK, %lu) failed",
> +					  tc->setvalue);
> +		return;
> +	}
> +
> +	tst_res(TPASS, "prctl(PR_SET_TIMERSLACK, %lu) succeed", tc->setvalue);
> +	tc->func_check(tc->message, tc->expvalue);
> +}
> +
> +static void setup(void)
> +{
> +	if (access(PROC_TIMERSLACK_PATH, F_OK) == -1) {
> +		tst_res(TCONF, "proc doesn't support timerslack_ns interface");
> +		proc_flag = 0;
> +	}
> +
> +	TEST(prctl(PR_GET_TIMERSLACK));
> +	if (TST_RET == 50000)
> +		tst_res(TINFO, "current timerslack value is 50us");
> +	else
> +		tst_brk(TCONF,
> +			"current environment doesn't meet test, please set timerslack to 50us");
> +}
> +
> +static struct tst_test test = {
> +	.setup = setup,
> +	.test = verify_prctl,
> +	.tcnt = ARRAY_SIZE(tcases),
> +	.forks_child = 1,
> +};
>