fix: event receiver loop from perf buffer

Signed-off-by: Alessio Greggi <ale_grey_91@hotmail.it>

ebpf/ebpf.c

@@ -83,7 +83,7 @@ int trace_syscall(struct trace_event_raw_sys_enter* args) {
 
  tc = bpf_map_lookup_elem(&tracing_status, &key_map_trace);
  if (!tc) {
- bpf_printk("error getting tracing status\n");
+ bpf_printk("error getting tracing status");
  return 1;
  }
  if (tc->status != 1) {

main.go

@@ -24,6 +24,8 @@ type event struct {
 //go:embed output/*
 var eBPFObject embed.FS
 var version = "test"
+var uprobeEnterFunc = "enter_function"
+var uprobeExitFunc = "exit_function"
 var tracepointCategory = "raw_syscalls"
 var tracepointName = "sys_enter"
 
@@ -89,15 +91,15 @@ func main() {
  }
 
  bpfModule.BPFLoadObject()
- enterFuncProbe, err := bpfModule.GetProgram("enter_function")
+ enterFuncProbe, err := bpfModule.GetProgram(uprobeEnterFunc)
  if err != nil {
- fmt.Printf("error loading program 'enter_function': %v\n", err)
+ fmt.Printf("error loading program '%s': %v\n", uprobeEnterFunc, err)
  os.Exit(-1)
  }
 
- exitFuncProbe, err := bpfModule.GetProgram("exit_function")
+ exitFuncProbe, err := bpfModule.GetProgram(uprobeExitFunc)
  if err != nil {
- fmt.Printf("error loading program 'exit_function': %v\n", err)
+ fmt.Printf("error loading program '%s': %v\n", uprobeExitFunc, err)
  os.Exit(-1)
  }
 
@@ -186,13 +188,19 @@ func main() {
 
  var syscalls []uint32
  go func() {
- for data := range eventsChannel {
- var e event
- if err := binary.Read(bytes.NewBuffer(data), binary.LittleEndian, &e); err != nil {
- fmt.Printf("failed to decode received data %q: %s\n", data, err)
- return
+ //for data := range eventsChannel {
+ for {
+ select {
+ case data := <-eventsChannel:
+ var e event
+ if err := binary.Read(bytes.NewBuffer(data), binary.LittleEndian, &e); err != nil {
+ fmt.Printf("failed to decode received data %q: %s\n", data, err)
+ return
+ }
+ syscalls = append(syscalls, e.SyscallID)
+ case lost := <-lostChannel:
+ fmt.Printf("lost %d data", lost)
  }
- syscalls = append(syscalls, e.SyscallID)
  }
  }()