116 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me>3 */4 5#define _GNU_SOURCE6#include <stdio.h>7#include <unistd.h>8#include <bpf/bpf.h>9#include <bpf/libbpf.h>10#include "cgroup_helpers.h"11 12#define CGROUP_PATH "/my-cgroup"13 14int main(int argc, char **argv)15{16 pid_t remote_pid, local_pid = getpid();17 int cg2 = -1, idx = 0, rc = 1;18 struct bpf_link *link = NULL;19 struct bpf_program *prog;20 struct bpf_object *obj;21 char filename[256];22 int map_fd[2];23 24 snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);25 obj = bpf_object__open_file(filename, NULL);26 if (libbpf_get_error(obj)) {27 fprintf(stderr, "ERROR: opening BPF object file failed\n");28 return 0;29 }30 31 prog = bpf_object__find_program_by_name(obj, "bpf_prog1");32 if (!prog) {33 printf("finding a prog in obj file failed\n");34 goto cleanup;35 }36 37 /* load BPF program */38 if (bpf_object__load(obj)) {39 fprintf(stderr, "ERROR: loading BPF object file failed\n");40 goto cleanup;41 }42 43 map_fd[0] = bpf_object__find_map_fd_by_name(obj, "cgroup_map");44 map_fd[1] = bpf_object__find_map_fd_by_name(obj, "perf_map");45 if (map_fd[0] < 0 || map_fd[1] < 0) {46 fprintf(stderr, "ERROR: finding a map in obj file failed\n");47 goto cleanup;48 }49 50 link = bpf_program__attach(prog);51 if (libbpf_get_error(link)) {52 fprintf(stderr, "ERROR: bpf_program__attach failed\n");53 link = NULL;54 goto cleanup;55 }56 57 if (setup_cgroup_environment())58 goto err;59 60 cg2 = create_and_get_cgroup(CGROUP_PATH);61 62 if (cg2 < 0)63 goto err;64 65 if (bpf_map_update_elem(map_fd[0], &idx, &cg2, BPF_ANY)) {66 log_err("Adding target cgroup to map");67 goto err;68 }69 70 if (join_cgroup(CGROUP_PATH))71 goto err;72 73 /*74 * The installed helper program catched the sync call, and should75 * write it to the map.76 */77 78 sync();79 bpf_map_lookup_elem(map_fd[1], &idx, &remote_pid);80 81 if (local_pid != remote_pid) {82 fprintf(stderr,83 "BPF Helper didn't write correct PID to map, but: %d\n",84 remote_pid);85 goto err;86 }87 88 /* Verify the negative scenario; leave the cgroup */89 if (join_cgroup("/"))90 goto err;91 92 remote_pid = 0;93 bpf_map_update_elem(map_fd[1], &idx, &remote_pid, BPF_ANY);94 95 sync();96 bpf_map_lookup_elem(map_fd[1], &idx, &remote_pid);97 98 if (local_pid == remote_pid) {99 fprintf(stderr, "BPF cgroup negative test did not work\n");100 goto err;101 }102 103 rc = 0;104 105err:106 if (cg2 != -1)107 close(cg2);108 109 cleanup_cgroup_environment();110 111cleanup:112 bpf_link__destroy(link);113 bpf_object__close(obj);114 return rc;115}116