mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-26 12:34:41 +08:00
d89af13c92
This commit refactors the existing cgroup program with libbpf bpf
loader. The original test_cgrp2_sock2 has keeped the bpf program
attached to the cgroup hierarchy even after the exit of user program.
To implement the same functionality with libbpf, this commit uses the
BPF_LINK_PINNING to pin the link attachment even after it is closed.
Since this uses LINK instead of ATTACH, detach of bpf program from
cgroup with 'test_cgrp2_sock' is not used anymore.
The code to mount the bpf was added to the .sh file in case the bpff
was not mounted on /sys/fs/bpf. Additionally, to fix the problem that
shell script cannot find the binary object from the current path,
relative path './' has been added in front of binary.
Fixes: 554ae6e792 ("samples/bpf: add userspace example for prohibiting sockets")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201124090310.24374-3-danieltimlee@gmail.com
96 lines
2.0 KiB
C
96 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/* eBPF example program:
|
|
*
|
|
* - Loads eBPF program
|
|
*
|
|
* The eBPF program loads a filter from file and attaches the
|
|
* program to a cgroup using BPF_PROG_ATTACH
|
|
*/
|
|
|
|
#define _GNU_SOURCE
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <stddef.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <net/if.h>
|
|
#include <linux/bpf.h>
|
|
#include <bpf/bpf.h>
|
|
#include <bpf/libbpf.h>
|
|
|
|
#include "bpf_insn.h"
|
|
|
|
static int usage(const char *argv0)
|
|
{
|
|
printf("Usage: %s cg-path filter-path [filter-id]\n", argv0);
|
|
return EXIT_FAILURE;
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
int cg_fd, err, ret = EXIT_FAILURE, filter_id = 0, prog_cnt = 0;
|
|
const char *link_pin_path = "/sys/fs/bpf/test_cgrp2_sock2";
|
|
struct bpf_link *link = NULL;
|
|
struct bpf_program *progs[2];
|
|
struct bpf_program *prog;
|
|
struct bpf_object *obj;
|
|
|
|
if (argc < 3)
|
|
return usage(argv[0]);
|
|
|
|
if (argc > 3)
|
|
filter_id = atoi(argv[3]);
|
|
|
|
cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY);
|
|
if (cg_fd < 0) {
|
|
printf("Failed to open cgroup path: '%s'\n", strerror(errno));
|
|
return ret;
|
|
}
|
|
|
|
obj = bpf_object__open_file(argv[2], NULL);
|
|
if (libbpf_get_error(obj)) {
|
|
printf("ERROR: opening BPF object file failed\n");
|
|
return ret;
|
|
}
|
|
|
|
bpf_object__for_each_program(prog, obj) {
|
|
progs[prog_cnt] = prog;
|
|
prog_cnt++;
|
|
}
|
|
|
|
if (filter_id >= prog_cnt) {
|
|
printf("Invalid program id; program not found in file\n");
|
|
goto cleanup;
|
|
}
|
|
|
|
/* load BPF program */
|
|
if (bpf_object__load(obj)) {
|
|
printf("ERROR: loading BPF object file failed\n");
|
|
goto cleanup;
|
|
}
|
|
|
|
link = bpf_program__attach_cgroup(progs[filter_id], cg_fd);
|
|
if (libbpf_get_error(link)) {
|
|
printf("ERROR: bpf_program__attach failed\n");
|
|
link = NULL;
|
|
goto cleanup;
|
|
}
|
|
|
|
err = bpf_link__pin(link, link_pin_path);
|
|
if (err < 0) {
|
|
printf("ERROR: bpf_link__pin failed: %d\n", err);
|
|
goto cleanup;
|
|
}
|
|
|
|
ret = EXIT_SUCCESS;
|
|
|
|
cleanup:
|
|
bpf_link__destroy(link);
|
|
bpf_object__close(obj);
|
|
return ret;
|
|
}
|