1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me> |
3 | */ |
4 | |
5 | #define _GNU_SOURCE |
6 | #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 | |
14 | int 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(s: filename, maxlen: sizeof(filename), format: "%s.bpf.o" , argv[0]); |
25 | obj = bpf_object__open_file(filename, NULL); |
26 | if (libbpf_get_error(obj)) { |
27 | fprintf(stderr, format: "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(format: "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, format: "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, format: "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, format: "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 should |
75 | * 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 | format: "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, format: "BPF cgroup negative test did not work\n" ); |
100 | goto err; |
101 | } |
102 | |
103 | rc = 0; |
104 | |
105 | err: |
106 | if (cg2 != -1) |
107 | close(fd: cg2); |
108 | |
109 | cleanup_cgroup_environment(); |
110 | |
111 | cleanup: |
112 | bpf_link__destroy(link); |
113 | bpf_object__close(obj); |
114 | return rc; |
115 | } |
116 | |