// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 Facebook
 */
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <linux/perf_event.h>
#include <errno.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>

/* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
 * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
 */

static void usage(const char *cmd)
{
        printf("USAGE: %s [-i nr_tests] [-h]\n", cmd);
        printf("       -i nr_tests      # rounds of test to run\n");
        printf("       -h               # help\n");
}

static void verify_map(int map_id)
{
        __u32 key = 0;
        __u32 val;

        if (bpf_map_lookup_elem(map_id, &key, &val) != 0) {
                fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
                return;
        }
        if (val == 0) {
                fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
                return;
        }

        printf("verify map:%d val: %d\n", map_id, val);

        val = 0;
        if (bpf_map_update_elem(map_id, &key, &val, BPF_ANY) != 0) {
                fprintf(stderr, "map_update failed: %s\n", strerror(errno));
                return;
        }
}

static int test(char *filename, int nr_tests)
{
        int map0_fds[nr_tests], map1_fds[nr_tests], fd, i, j = 0;
        struct bpf_link **links = NULL;
        struct bpf_object *objs[nr_tests];
        struct bpf_program *prog;

        for (i = 0; i < nr_tests; i++) {
                objs[i] = bpf_object__open_file(filename, NULL);
                if (libbpf_get_error(objs[i])) {
                        fprintf(stderr, "opening BPF object file failed\n");
                        objs[i] = NULL;
                        goto cleanup;
                }

                /* One-time initialization */
                if (!links) {
                        int nr_progs = 0;

                        bpf_object__for_each_program(prog, objs[i])
                                nr_progs += 1;

                        links = calloc(nr_progs * nr_tests, sizeof(struct bpf_link *));

                        if (!links)
                                goto cleanup;
                }

                /* load BPF program */
                if (bpf_object__load(objs[i])) {
                        fprintf(stderr, "loading BPF object file failed\n");
                        goto cleanup;
                }

                map0_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
                                                              "enter_open_map");
                map1_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
                                                              "exit_open_map");
                if (map0_fds[i] < 0 || map1_fds[i] < 0) {
                        fprintf(stderr, "finding a map in obj file failed\n");
                        goto cleanup;
                }

                bpf_object__for_each_program(prog, objs[i]) {
                        links[j] = bpf_program__attach(prog);
                        if (libbpf_get_error(links[j])) {
                                fprintf(stderr, "bpf_program__attach failed\n");
                                links[j] = NULL;
                                goto cleanup;
                        }
                        j++;
                }
                printf("prog #%d: map ids %d %d\n", i, map0_fds[i], map1_fds[i]);
        }

        /* current load_bpf_file has perf_event_open default pid = -1
         * and cpu = 0, which permits attached bpf execution on
         * all cpus for all pid's. bpf program execution ignores
         * cpu affinity.
         */
        /* trigger some "open" operations */
        fd = open(filename, O_RDONLY);
        if (fd < 0) {
                fprintf(stderr, "open failed: %s\n", strerror(errno));
                return 1;
        }
        close(fd);

        /* verify the map */
        for (i = 0; i < nr_tests; i++) {
                verify_map(map0_fds[i]);
                verify_map(map1_fds[i]);
        }

cleanup:
        if (links) {
                for (j--; j >= 0; j--)
                        bpf_link__destroy(links[j]);

                free(links);
        }

        for (i--; i >= 0; i--)
                bpf_object__close(objs[i]);
        return 0;
}

int main(int argc, char **argv)
{
        int opt, nr_tests = 1;
        char filename[256];

        while ((opt = getopt(argc, argv, "i:h")) != -1) {
                switch (opt) {
                case 'i':
                        nr_tests = atoi(optarg);
                        break;
                case 'h':
                default:
                        usage(argv[0]);
                        return 0;
                }
        }

        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);

        return test(filename, nr_tests);
}