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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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