samples/bpf/test_cgrp2_array_pin.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /* Copyright (c) 2016 Facebook
0003  */
0004 #include <linux/unistd.h>
0005 #include <linux/bpf.h>
0006
0007 #include <stdio.h>
0008 #include <stdint.h>
0009 #include <unistd.h>
0010 #include <string.h>
0011 #include <errno.h>
0012 #include <fcntl.h>
0013
0014 #include <bpf/bpf.h>
0015
0016 static void usage(void)
0017 {
0018     printf("Usage: test_cgrp2_array_pin [...]\n");
0019     printf("       -F <file>   File to pin an BPF cgroup array\n");
0020     printf("       -U <file>   Update an already pinned BPF cgroup array\n");
0021     printf("       -v <value>  Full path of the cgroup2\n");
0022     printf("       -h          Display this help\n");
0023 }
0024
0025 int main(int argc, char **argv)
0026 {
0027     const char *pinned_file = NULL, *cg2 = NULL;
0028     int create_array = 1;
0029     int array_key = 0;
0030     int array_fd = -1;
0031     int cg2_fd = -1;
0032     int ret = -1;
0033     int opt;
0034
0035     while ((opt = getopt(argc, argv, "F:U:v:")) != -1) {
0036         switch (opt) {
0037         /* General args */
0038         case 'F':
0039             pinned_file = optarg;
0040             break;
0041         case 'U':
0042             pinned_file = optarg;
0043             create_array = 0;
0044             break;
0045         case 'v':
0046             cg2 = optarg;
0047             break;
0048         default:
0049             usage();
0050             goto out;
0051         }
0052     }
0053
0054     if (!cg2 || !pinned_file) {
0055         usage();
0056         goto out;
0057     }
0058
0059     cg2_fd = open(cg2, O_RDONLY);
0060     if (cg2_fd < 0) {
0061         fprintf(stderr, "open(%s,...): %s(%d)\n",
0062             cg2, strerror(errno), errno);
0063         goto out;
0064     }
0065
0066     if (create_array) {
0067         array_fd = bpf_map_create(BPF_MAP_TYPE_CGROUP_ARRAY, NULL,
0068                       sizeof(uint32_t), sizeof(uint32_t),
0069                       1, NULL);
0070         if (array_fd < 0) {
0071             fprintf(stderr,
0072                 "bpf_create_map(BPF_MAP_TYPE_CGROUP_ARRAY,...): %s(%d)\n",
0073                 strerror(errno), errno);
0074             goto out;
0075         }
0076     } else {
0077         array_fd = bpf_obj_get(pinned_file);
0078         if (array_fd < 0) {
0079             fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
0080                 pinned_file, strerror(errno), errno);
0081             goto out;
0082         }
0083     }
0084
0085     ret = bpf_map_update_elem(array_fd, &array_key, &cg2_fd, 0);
0086     if (ret) {
0087         perror("bpf_map_update_elem");
0088         goto out;
0089     }
0090
0091     if (create_array) {
0092         ret = bpf_obj_pin(array_fd, pinned_file);
0093         if (ret) {
0094             fprintf(stderr, "bpf_obj_pin(..., %s): %s(%d)\n",
0095                 pinned_file, strerror(errno), errno);
0096             goto out;
0097         }
0098     }
0099
0100 out:
0101     if (array_fd != -1)
0102         close(array_fd);
0103     if (cg2_fd != -1)
0104         close(cg2_fd);
0105     return ret;
0106 }