62 lines
1.7 KiB
Go
62 lines
1.7 KiB
Go
// This program demonstrates attaching an eBPF program to a kernel symbol.
|
|
// The eBPF program will be attached to the start of the sys_execve
|
|
// kernel function and prints out the number of times it has been called
|
|
// every second.
|
|
package main
|
|
|
|
import (
|
|
"log"
|
|
"time"
|
|
|
|
"github.com/cilium/ebpf/link"
|
|
"github.com/cilium/ebpf/rlimit"
|
|
)
|
|
|
|
// $BPF_CLANG and $BPF_CFLAGS are set by the Makefile.
|
|
//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc $BPF_CLANG -cflags $BPF_CFLAGS bpf kprobe.c -- -I../headers
|
|
|
|
const mapKey uint32 = 0
|
|
|
|
func main() {
|
|
|
|
// Name of the kernel function to trace.
|
|
fn := "sys_execve"
|
|
|
|
// Allow the current process to lock memory for eBPF resources.
|
|
if err := rlimit.RemoveMemlock(); err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
|
|
// Load pre-compiled programs and maps into the kernel.
|
|
objs := bpfObjects{}
|
|
if err := loadBpfObjects(&objs, nil); err != nil {
|
|
log.Fatalf("loading objects: %v", err)
|
|
}
|
|
defer objs.Close()
|
|
|
|
// Open a Kprobe at the entry point of the kernel function and attach the
|
|
// pre-compiled program. Each time the kernel function enters, the program
|
|
// will increment the execution counter by 1. The read loop below polls this
|
|
// map value once per second.
|
|
kp, err := link.Kprobe(fn, objs.KprobeExecve, nil)
|
|
if err != nil {
|
|
log.Fatalf("opening kprobe: %s", err)
|
|
}
|
|
defer kp.Close()
|
|
|
|
// Read loop reporting the total amount of times the kernel
|
|
// function was entered, once per second.
|
|
ticker := time.NewTicker(1 * time.Second)
|
|
defer ticker.Stop()
|
|
|
|
log.Println("Waiting for events..")
|
|
|
|
for range ticker.C {
|
|
var value uint64
|
|
if err := objs.KprobeMap.Lookup(mapKey, &value); err != nil {
|
|
log.Fatalf("reading map: %v", err)
|
|
}
|
|
log.Printf("%s called %d times\n", fn, value)
|
|
}
|
|
}
|