基于ebpf写一个hello_world
时间: 2024-01-03 17:04:46 浏览: 30
以下是基于eBPF写一个hello_world的步骤:
1.安装依赖项和工具链
```shell
sudo apt-get update
sudo apt-get install -y build-essential linux-headers-$(uname -r) libelf-dev clang llvm
```
2.创建一个名为helloworld.bpf.c的文件,并将以下代码复制到文件中:
```c
#include <linux/bpf.h>
#include <linux/version.h>
#include <stddef.h>
#include <stdint.h>
char _license[] SEC("license") = "GPL";
int _version SEC("version") = LINUX_VERSION_CODE;
SEC("kprobe/sys_clone")
int bpf_prog(void *ctx)
{
char msg[] = "Hello, World!";
bpf_trace_printk(msg, sizeof(msg));
return 0;
}
```
3.创建一个名为helloworld.c的文件,并将以下代码复制到文件中:
```c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/bpf.h>
#include <bpf/libbpf.h>
int main(int argc, char **argv)
{
struct bpf_object *obj; int prog_fd, err;
/* Load the BPF object file */
err = bpf_prog_load("helloworld.bpf.o", BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
if (err) {
fprintf(stderr, "Failed to load BPF object file: %s\n", strerror(-err));
return EXIT_FAILURE;
}
/* Attach the BPF program to the kprobe/sys_clone kernel function */
err = bpf_attach_kprobe(prog_fd, BPF_PROBE_ENTRY, "sys_clone");
if (err) {
fprintf(stderr, "Failed to attach BPF program to kprobe/sys_clone: %s\n", strerror(-err));
return EXIT_FAILURE;
}
/* Wait for the user to press Enter */
printf("Press Enter to detach the BPF program...\n");
getchar();
/* Detach the BPF program from the kprobe/sys_clone kernel function */
err = bpf_detach_kprobe(prog_fd, BPF_PROBE_ENTRY, "sys_clone");
if (err) {
fprintf(stderr, "Failed to detach BPF program from kprobe/sys_clone: %s\n", strerror(-err));
return EXIT_FAILURE;
}
/* Clean up */
bpf_object__close(obj);
return EXIT_SUCCESS;
}
```
4.编译和链接BPF程序
```shell
clang -O2 -target bpf -c helloworld.bpf.c -o helloworld.bpf.o
```
5.编译和链接用户空间程序
```shell
clang helloworld.c -o helloworld -lbpf
```
6.运行用户空间程序
```shell
sudo ./helloworld
```
7.在另一个终端窗口中查看BPF程序的输出
```shell
sudo cat /sys/kernel/debug/tracing/trace_pipe
```