diff options
Diffstat (limited to 'vendor/github.com/cilium/ebpf/link/tracing.go')
-rw-r--r-- | vendor/github.com/cilium/ebpf/link/tracing.go | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/vendor/github.com/cilium/ebpf/link/tracing.go b/vendor/github.com/cilium/ebpf/link/tracing.go new file mode 100644 index 000000000..e47e61a3b --- /dev/null +++ b/vendor/github.com/cilium/ebpf/link/tracing.go @@ -0,0 +1,141 @@ +package link + +import ( + "fmt" + + "github.com/cilium/ebpf" + "github.com/cilium/ebpf/btf" + "github.com/cilium/ebpf/internal/sys" +) + +type tracing struct { + RawLink +} + +func (f *tracing) Update(new *ebpf.Program) error { + return fmt.Errorf("tracing update: %w", ErrNotSupported) +} + +// AttachFreplace attaches the given eBPF program to the function it replaces. +// +// The program and name can either be provided at link time, or can be provided +// at program load time. If they were provided at load time, they should be nil +// and empty respectively here, as they will be ignored by the kernel. +// Examples: +// +// AttachFreplace(dispatcher, "function", replacement) +// AttachFreplace(nil, "", replacement) +func AttachFreplace(targetProg *ebpf.Program, name string, prog *ebpf.Program) (Link, error) { + if (name == "") != (targetProg == nil) { + return nil, fmt.Errorf("must provide both or neither of name and targetProg: %w", errInvalidInput) + } + if prog == nil { + return nil, fmt.Errorf("prog cannot be nil: %w", errInvalidInput) + } + if prog.Type() != ebpf.Extension { + return nil, fmt.Errorf("eBPF program type %s is not an Extension: %w", prog.Type(), errInvalidInput) + } + + var ( + target int + typeID btf.TypeID + ) + if targetProg != nil { + btfHandle, err := targetProg.Handle() + if err != nil { + return nil, err + } + defer btfHandle.Close() + + spec, err := btfHandle.Spec(nil) + if err != nil { + return nil, err + } + + var function *btf.Func + if err := spec.TypeByName(name, &function); err != nil { + return nil, err + } + + target = targetProg.FD() + typeID, err = spec.TypeID(function) + if err != nil { + return nil, err + } + } + + link, err := AttachRawLink(RawLinkOptions{ + Target: target, + Program: prog, + Attach: ebpf.AttachNone, + BTF: typeID, + }) + if err != nil { + return nil, err + } + + return &tracing{*link}, nil +} + +type TracingOptions struct { + // Program must be of type Tracing with attach type + // AttachTraceFEntry/AttachTraceFExit/AttachModifyReturn or + // AttachTraceRawTp. + Program *ebpf.Program +} + +type LSMOptions struct { + // Program must be of type LSM with attach type + // AttachLSMMac. + Program *ebpf.Program +} + +// attachBTFID links all BPF program types (Tracing/LSM) that they attach to a btf_id. +func attachBTFID(program *ebpf.Program) (Link, error) { + if program.FD() < 0 { + return nil, fmt.Errorf("invalid program %w", sys.ErrClosedFd) + } + + fd, err := sys.RawTracepointOpen(&sys.RawTracepointOpenAttr{ + ProgFd: uint32(program.FD()), + }) + if err != nil { + return nil, err + } + + raw := RawLink{fd: fd} + info, err := raw.Info() + if err != nil { + raw.Close() + return nil, err + } + + if info.Type == RawTracepointType { + // Sadness upon sadness: a Tracing program with AttachRawTp returns + // a raw_tracepoint link. Other types return a tracing link. + return &rawTracepoint{raw}, nil + } + + return &tracing{RawLink: RawLink{fd: fd}}, nil +} + +// AttachTracing links a tracing (fentry/fexit/fmod_ret) BPF program or +// a BTF-powered raw tracepoint (tp_btf) BPF Program to a BPF hook defined +// in kernel modules. +func AttachTracing(opts TracingOptions) (Link, error) { + if t := opts.Program.Type(); t != ebpf.Tracing { + return nil, fmt.Errorf("invalid program type %s, expected Tracing", t) + } + + return attachBTFID(opts.Program) +} + +// AttachLSM links a Linux security module (LSM) BPF Program to a BPF +// hook defined in kernel modules. +func AttachLSM(opts LSMOptions) (Link, error) { + if t := opts.Program.Type(); t != ebpf.LSM { + return nil, fmt.Errorf("invalid program type %s, expected LSM", t) + } + + return attachBTFID(opts.Program) +} |