// SPDX-License-Identifier: GPL-2.0-only
#include <stdio.h>
#include <fcntl.h>
#include <poll.h>
#include <time.h>
#include <signal.h>
#include <bpf/libbpf.h>

static __u64 time_get_ns(void)
{
        struct timespec ts;

        clock_gettime(CLOCK_MONOTONIC, &ts);
        return ts.tv_sec * 1000000000ull + ts.tv_nsec;
}

static __u64 start_time;
static __u64 cnt;

#define MAX_CNT 100000ll

static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size)
{
        struct {
                __u64 pid;
                __u64 cookie;
        } *e = data;

        if (e->cookie != 0x12345678) {
                printf("BUG pid %llx cookie %llx sized %d\n",
                       e->pid, e->cookie, size);
                return;
        }

        cnt++;

        if (cnt == MAX_CNT) {
                printf("recv %lld events per sec\n",
                       MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
                return;
        }
}

int main(int argc, char **argv)
{
        struct bpf_link *link = NULL;
        struct bpf_program *prog;
        struct perf_buffer *pb;
        struct bpf_object *obj;
        int map_fd, ret = 0;
        char filename[256];
        FILE *f;

        snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);
        obj = bpf_object__open_file(filename, NULL);
        if (libbpf_get_error(obj)) {
                fprintf(stderr, "ERROR: opening BPF object file failed\n");
                return 0;
        }

        /* load BPF program */
        if (bpf_object__load(obj)) {
                fprintf(stderr, "ERROR: loading BPF object file failed\n");
                goto cleanup;
        }

        map_fd = bpf_object__find_map_fd_by_name(obj, "my_map");
        if (map_fd < 0) {
                fprintf(stderr, "ERROR: finding a map in obj file failed\n");
                goto cleanup;
        }

        prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
        if (libbpf_get_error(prog)) {
                fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
                goto cleanup;
        }

        link = bpf_program__attach(prog);
        if (libbpf_get_error(link)) {
                fprintf(stderr, "ERROR: bpf_program__attach failed\n");
                link = NULL;
                goto cleanup;
        }

        pb = perf_buffer__new(map_fd, 8, print_bpf_output, NULL, NULL, NULL);
        ret = libbpf_get_error(pb);
        if (ret) {
                printf("failed to setup perf_buffer: %d\n", ret);
                return 1;
        }

        f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r");
        (void) f;

        start_time = time_get_ns();
        while ((ret = perf_buffer__poll(pb, 1000)) >= 0 && cnt < MAX_CNT) {
        }
        kill(0, SIGINT);

cleanup:
        bpf_link__destroy(link);
        bpf_object__close(obj);
        return ret;
}