1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2016 Facebook
3  */
4 #include <linux/unistd.h>
5 #include <linux/bpf.h>
6 
7 #include <stdio.h>
8 #include <stdint.h>
9 #include <unistd.h>
10 #include <string.h>
11 #include <errno.h>
12 #include <fcntl.h>
13 
14 #include <bpf/bpf.h>
15 
16 static void usage(void)
17 {
18 	printf("Usage: test_cgrp2_array_pin [...]\n");
19 	printf("       -F <file>   File to pin an BPF cgroup array\n");
20 	printf("       -U <file>   Update an already pinned BPF cgroup array\n");
21 	printf("       -v <value>  Full path of the cgroup2\n");
22 	printf("       -h          Display this help\n");
23 }
24 
25 int main(int argc, char **argv)
26 {
27 	const char *pinned_file = NULL, *cg2 = NULL;
28 	int create_array = 1;
29 	int array_key = 0;
30 	int array_fd = -1;
31 	int cg2_fd = -1;
32 	int ret = -1;
33 	int opt;
34 
35 	while ((opt = getopt(argc, argv, "F:U:v:")) != -1) {
36 		switch (opt) {
37 		/* General args */
38 		case 'F':
39 			pinned_file = optarg;
40 			break;
41 		case 'U':
42 			pinned_file = optarg;
43 			create_array = 0;
44 			break;
45 		case 'v':
46 			cg2 = optarg;
47 			break;
48 		default:
49 			usage();
50 			goto out;
51 		}
52 	}
53 
54 	if (!cg2 || !pinned_file) {
55 		usage();
56 		goto out;
57 	}
58 
59 	cg2_fd = open(cg2, O_RDONLY);
60 	if (cg2_fd < 0) {
61 		fprintf(stderr, "open(%s,...): %s(%d)\n",
62 			cg2, strerror(errno), errno);
63 		goto out;
64 	}
65 
66 	if (create_array) {
67 		array_fd = bpf_map_create(BPF_MAP_TYPE_CGROUP_ARRAY, NULL,
68 					  sizeof(uint32_t), sizeof(uint32_t),
69 					  1, NULL);
70 		if (array_fd < 0) {
71 			fprintf(stderr,
72 				"bpf_create_map(BPF_MAP_TYPE_CGROUP_ARRAY,...): %s(%d)\n",
73 				strerror(errno), errno);
74 			goto out;
75 		}
76 	} else {
77 		array_fd = bpf_obj_get(pinned_file);
78 		if (array_fd < 0) {
79 			fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
80 				pinned_file, strerror(errno), errno);
81 			goto out;
82 		}
83 	}
84 
85 	ret = bpf_map_update_elem(array_fd, &array_key, &cg2_fd, 0);
86 	if (ret) {
87 		perror("bpf_map_update_elem");
88 		goto out;
89 	}
90 
91 	if (create_array) {
92 		ret = bpf_obj_pin(array_fd, pinned_file);
93 		if (ret) {
94 			fprintf(stderr, "bpf_obj_pin(..., %s): %s(%d)\n",
95 				pinned_file, strerror(errno), errno);
96 			goto out;
97 		}
98 	}
99 
100 out:
101 	if (array_fd != -1)
102 		close(array_fd);
103 	if (cg2_fd != -1)
104 		close(cg2_fd);
105 	return ret;
106 }
107