samples/bpf/test_cgrp2_array_pin.c

   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_create_map(BPF_MAP_TYPE_CGROUP_ARRAY,
  68                                           sizeof(uint32_t), sizeof(uint32_t),
  69                                           1, 0);
  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 }