LXR linux/samples/bpf/test_cgrp2_array

   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 "libbpf.h"
  18
  19static 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
  28int 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
 103out:
 104        if (array_fd != -1)
 105                close(array_fd);
 106        if (cg2_fd != -1)
 107                close(cg2_fd);
 108        return ret;
 109}
 110