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}