selftests/bpf: Add send_signal_sched_switch test

// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>

#include <stdio.h>

#include <stdlib.h>

#include <sys/mman.h>

#include <pthread.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include "test_send_signal_kern.skel.h"

static void sigusr1_handler(int signum)

{

}

#define THREAD_COUNT 100

static void *worker(void *p)

{

	int i;

	for ( i = 0; i < 1000; i++)

		usleep(1);

	return NULL;

}

void test_send_signal_sched_switch(void)

{

	struct test_send_signal_kern *skel;

	pthread_t threads[THREAD_COUNT];

	u32 duration = 0;

	int i, err;

	signal(SIGUSR1, sigusr1_handler);

	skel = test_send_signal_kern__open_and_load();

	if (CHECK(!skel, "skel_open_and_load", "skeleton open_and_load failed\n"))

		return;

	skel->bss->pid = getpid();

	skel->bss->sig = SIGUSR1;

	err = test_send_signal_kern__attach(skel);

	if (CHECK(err, "skel_attach", "skeleton attach failed\n"))

		goto destroy_skel;

	for (i = 0; i < THREAD_COUNT; i++) {

		err = pthread_create(threads + i, NULL, worker, NULL);

		if (CHECK(err, "pthread_create", "Error creating thread, %s\n",

			  strerror(errno)))

			goto destroy_skel;

	}

	for (i = 0; i < THREAD_COUNT; i++)

		pthread_join(threads[i], NULL);

destroy_skel:

	test_send_signal_kern__destroy(skel);

}

	return bpf_send_signal_test(ctx);

}

SEC("tracepoint/sched/sched_switch")

int send_signal_tp_sched(void *ctx)

{

	return bpf_send_signal_test(ctx);

}

SEC("perf_event")

int send_signal_perf(void *ctx)

{