package link import ( "fmt" "github.com/cilium/ebpf" ) // Tracepoint attaches the given eBPF program to the tracepoint with the given // group and name. See /sys/kernel/debug/tracing/events to find available // tracepoints. The top-level directory is the group, the event's subdirectory // is the name. Example: // // tp, err := Tracepoint("syscalls", "sys_enter_fork", prog) // // Losing the reference to the resulting Link (tp) will close the Tracepoint // and prevent further execution of prog. The Link must be Closed during // program shutdown to avoid leaking system resources. // // Note that attaching eBPF programs to syscalls (sys_enter_*/sys_exit_*) is // only possible as of kernel 4.14 (commit cf5f5ce). func Tracepoint(group, name string, prog *ebpf.Program) (Link, error) { if group == "" || name == "" { return nil, fmt.Errorf("group and name cannot be empty: %w", errInvalidInput) } if prog == nil { return nil, fmt.Errorf("prog cannot be nil: %w", errInvalidInput) } if !rgxTraceEvent.MatchString(group) || !rgxTraceEvent.MatchString(name) { return nil, fmt.Errorf("group and name '%s/%s' must be alphanumeric or underscore: %w", group, name, errInvalidInput) } if prog.Type() != ebpf.TracePoint { return nil, fmt.Errorf("eBPF program type %s is not a Tracepoint: %w", prog.Type(), errInvalidInput) } tid, err := getTraceEventID(group, name) if err != nil { return nil, err } fd, err := openTracepointPerfEvent(tid, perfAllThreads) if err != nil { return nil, err } pe := &perfEvent{ fd: fd, tracefsID: tid, group: group, name: name, typ: tracepointEvent, } if err := pe.attach(prog); err != nil { pe.Close() return nil, err } return pe, nil }