/* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me> * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. */ #define _GNU_SOURCE #include <stdio.h> #include <linux/bpf.h> #include <unistd.h> #include <bpf/bpf.h> #include "bpf_load.h" #include "cgroup_helpers.h" #define CGROUP_PATH "/my-cgroup" int main(int argc, char **argv) { pid_t remote_pid, local_pid = getpid(); int cg2, idx = 0, rc = 0; char filename[256]; snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); if (load_bpf_file(filename)) { printf("%s", bpf_log_buf); return 1; } if (setup_cgroup_environment()) goto err; cg2 = create_and_get_cgroup(CGROUP_PATH); if (!cg2) goto err; if (bpf_map_update_elem(map_fd[0], &idx, &cg2, BPF_ANY)) { log_err("Adding target cgroup to map"); goto err; } if (join_cgroup(CGROUP_PATH)) goto err; /* * The installed helper program catched the sync call, and should * write it to the map. */ sync(); bpf_map_lookup_elem(map_fd[1], &idx, &remote_pid); if (local_pid != remote_pid) { fprintf(stderr, "BPF Helper didn't write correct PID to map, but: %d\n", remote_pid); goto err; } /* Verify the negative scenario; leave the cgroup */ if (join_cgroup("/")) goto err; remote_pid = 0; bpf_map_update_elem(map_fd[1], &idx, &remote_pid, BPF_ANY); sync(); bpf_map_lookup_elem(map_fd[1], &idx, &remote_pid); if (local_pid == remote_pid) { fprintf(stderr, "BPF cgroup negative test did not work\n"); goto err; } goto out; err: rc = 1; out: close(cg2); cleanup_cgroup_environment(); return rc; }