samples/bpf/test_cgrp2_array_pin.c

   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 }