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- // SPDX-License-Identifier: GPL-2.0-only
- /* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me>
- */
- #define _GNU_SOURCE
- #include <stdio.h>
- #include <unistd.h>
- #include <bpf/bpf.h>
- #include <bpf/libbpf.h>
- #include "cgroup_helpers.h"
- #define CGROUP_PATH "/my-cgroup"
- int main(int argc, char **argv)
- {
- pid_t remote_pid, local_pid = getpid();
- struct bpf_link *link = NULL;
- struct bpf_program *prog;
- int cg2, idx = 0, rc = 1;
- struct bpf_object *obj;
- char filename[256];
- int map_fd[2];
- snprintf(filename, sizeof(filename), "%s_kern.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;
- }
- prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
- if (!prog) {
- printf("finding a prog in obj file failed\n");
- goto cleanup;
- }
- /* load BPF program */
- if (bpf_object__load(obj)) {
- fprintf(stderr, "ERROR: loading BPF object file failed\n");
- goto cleanup;
- }
- map_fd[0] = bpf_object__find_map_fd_by_name(obj, "cgroup_map");
- map_fd[1] = bpf_object__find_map_fd_by_name(obj, "perf_map");
- if (map_fd[0] < 0 || map_fd[1] < 0) {
- fprintf(stderr, "ERROR: finding a map 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;
- }
- if (setup_cgroup_environment())
- goto err;
- cg2 = create_and_get_cgroup(CGROUP_PATH);
- if (cg2 < 0)
- 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;
- }
- rc = 0;
- err:
- close(cg2);
- cleanup_cgroup_environment();
- cleanup:
- bpf_link__destroy(link);
- bpf_object__close(obj);
- return rc;
- }
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