1 /* Copyright (c) 2016 Facebook
2  *
3  * This program is free software; you can redistribute it and/or
4  * modify it under the terms of version 2 of the GNU General Public
5  * License as published by the Free Software Foundation.
6  */
7 #include <linux/unistd.h>
8 #include <linux/bpf.h>
9 
10 #include <stdio.h>
11 #include <stdint.h>
12 #include <unistd.h>
13 #include <string.h>
14 #include <errno.h>
15 #include <fcntl.h>
16 
17 #include <bpf/bpf.h>
18 
19 static void usage(void)
20 {
21 	printf("Usage: test_cgrp2_array_pin [...]\n");
22 	printf("       -F <file>   File to pin an BPF cgroup array\n");
23 	printf("       -U <file>   Update an already pinned BPF cgroup array\n");
24 	printf("       -v <value>  Full path of the cgroup2\n");
25 	printf("       -h          Display this help\n");
26 }
27 
28 int main(int argc, char **argv)
29 {
30 	const char *pinned_file = NULL, *cg2 = NULL;
31 	int create_array = 1;
32 	int array_key = 0;
33 	int array_fd = -1;
34 	int cg2_fd = -1;
35 	int ret = -1;
36 	int opt;
37 
38 	while ((opt = getopt(argc, argv, "F:U:v:")) != -1) {
39 		switch (opt) {
40 		/* General args */
41 		case 'F':
42 			pinned_file = optarg;
43 			break;
44 		case 'U':
45 			pinned_file = optarg;
46 			create_array = 0;
47 			break;
48 		case 'v':
49 			cg2 = optarg;
50 			break;
51 		default:
52 			usage();
53 			goto out;
54 		}
55 	}
56 
57 	if (!cg2 || !pinned_file) {
58 		usage();
59 		goto out;
60 	}
61 
62 	cg2_fd = open(cg2, O_RDONLY);
63 	if (cg2_fd < 0) {
64 		fprintf(stderr, "open(%s,...): %s(%d)\n",
65 			cg2, strerror(errno), errno);
66 		goto out;
67 	}
68 
69 	if (create_array) {
70 		array_fd = bpf_create_map(BPF_MAP_TYPE_CGROUP_ARRAY,
71 					  sizeof(uint32_t), sizeof(uint32_t),
72 					  1, 0);
73 		if (array_fd < 0) {
74 			fprintf(stderr,
75 				"bpf_create_map(BPF_MAP_TYPE_CGROUP_ARRAY,...): %s(%d)\n",
76 				strerror(errno), errno);
77 			goto out;
78 		}
79 	} else {
80 		array_fd = bpf_obj_get(pinned_file);
81 		if (array_fd < 0) {
82 			fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
83 				pinned_file, strerror(errno), errno);
84 			goto out;
85 		}
86 	}
87 
88 	ret = bpf_map_update_elem(array_fd, &array_key, &cg2_fd, 0);
89 	if (ret) {
90 		perror("bpf_map_update_elem");
91 		goto out;
92 	}
93 
94 	if (create_array) {
95 		ret = bpf_obj_pin(array_fd, pinned_file);
96 		if (ret) {
97 			fprintf(stderr, "bpf_obj_pin(..., %s): %s(%d)\n",
98 				pinned_file, strerror(errno), errno);
99 			goto out;
100 		}
101 	}
102 
103 out:
104 	if (array_fd != -1)
105 		close(array_fd);
106 	if (cg2_fd != -1)
107 		close(cg2_fd);
108 	return ret;
109 }
110