selftests/bpf: Test BPF_MAP_TYPE_PROG_ARRAY static initialization

/* SPDX-License-Identifier: GPL-2.0 */

/* Copyright (c) 2021 Hengqi Chen */

#include <test_progs.h>

#include "test_prog_array_init.skel.h"

void test_prog_array_init(void)

{

	struct test_prog_array_init *skel;

	int err;

	skel = test_prog_array_init__open();

	if (!ASSERT_OK_PTR(skel, "could not open BPF object"))

		return;

	skel->rodata->my_pid = getpid();

	err = test_prog_array_init__load(skel);

	if (!ASSERT_OK(err, "could not load BPF object"))

		goto cleanup;

	skel->links.entry = bpf_program__attach_raw_tracepoint(skel->progs.entry, "sys_enter");

	if (!ASSERT_OK_PTR(skel->links.entry, "could not attach BPF program"))

		goto cleanup;

	usleep(1);

	ASSERT_EQ(skel->bss->value, 42, "unexpected value");

cleanup:

	test_prog_array_init__destroy(skel);

}

/* SPDX-License-Identifier: GPL-2.0 */

/* Copyright (c) 2021 Hengqi Chen */

#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

const volatile pid_t my_pid = 0;

int value = 0;

SEC("raw_tp/sys_enter")

int tailcall_1(void *ctx)

{

	value = 42;

	return 0;

}

struct {

	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);

	__uint(max_entries, 2);

	__uint(key_size, sizeof(__u32));

	__array(values, int (void *));

} prog_array_init SEC(".maps") = {

	.values = {

		[1] = (void *)&tailcall_1,

	},

};

SEC("raw_tp/sys_enter")

int entry(void *ctx)

{

	pid_t pid = bpf_get_current_pid_tgid() >> 32;

	if (pid != my_pid)

		return 0;

	bpf_tail_call(ctx, &prog_array_init, 1);

	return 0;

}