uprobe/kprobe: Add setupCelExpr and use it to setup cel expression

Signed-off-by: Jiri Olsa <jolsa@kernel.org>

Author: olsajiri

pkg/sensors/tracing/generic.go

@@ -10,9 +10,12 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/cilium/ebpf"
 	ebtf "github.com/cilium/ebpf/btf"
 
+	"github.com/cilium/tetragon/pkg/celbpf"
 	"github.com/cilium/tetragon/pkg/k8s/apis/cilium.io/v1alpha1"
+	"github.com/cilium/tetragon/pkg/sensors/program"
 
 	api "github.com/cilium/tetragon/pkg/api/tracingapi"
 	"github.com/cilium/tetragon/pkg/btf"
@@ -308,3 +311,15 @@ func useMacro[T any](filters []T, macrosFilters []T) ([]T, error) {
 	}
 	return append(filters, macrosFilters...), nil
 }
+
+func setupCelExpr(load *program.Program, selectors kprobeSelectors, fn string) {
+	if !celbpf.EnabledInBPF() || load.RewriteProg != nil {
+		return
+	}
+
+	rewriteProg := make(map[string]func(prog *ebpf.ProgramSpec) error)
+	if entry := selectors.entry; entry != nil {
+		rewriteProg[fn] = entry.CelExprFunctions().RewriteProg
+		load.RewriteProg = rewriteProg
+	}
+}

pkg/sensors/tracing/generickprobe.go

@@ -30,7 +30,6 @@ import (
 	"github.com/cilium/tetragon/pkg/asm"
 	"github.com/cilium/tetragon/pkg/bpf"
 	"github.com/cilium/tetragon/pkg/btf"
-	"github.com/cilium/tetragon/pkg/celbpf"
 	"github.com/cilium/tetragon/pkg/cgtracker"
 	"github.com/cilium/tetragon/pkg/config"
 	"github.com/cilium/tetragon/pkg/eventhandler"
@@ -1220,13 +1219,7 @@ func loadSingleKprobeSensor(id idtable.EntryID, bpfDir string, load *program.Pro
 		return err
 	}
 
-	rewriteProg := make(map[string]func(prog *ebpf.ProgramSpec) error)
-	if entry := gk.loadArgs.selectors.entry; entry != nil {
-		if celbpf.EnabledInBPF() {
-			rewriteProg["generic_kprobe_filter_arg"] = entry.CelExprFunctions().RewriteProg
-		}
-	}
-	load.RewriteProg = rewriteProg
+	setupCelExpr(load, gk.loadArgs.selectors, "generic_kprobe_filter_arg")
 
 	load.MapLoad = append(load.MapLoad, getMapLoad(load, gk, 0)...)
 
@@ -1264,13 +1257,7 @@ func loadMultiKprobeSensor(ids []idtable.EntryID, bpfDir string, load *program.P
 			return err
 		}
 
-		rewriteProg := make(map[string]func(prog *ebpf.ProgramSpec) error)
-		if entry := gk.loadArgs.selectors.entry; entry != nil {
-			if celbpf.EnabledInBPF() {
-				rewriteProg["generic_kprobe_filter_arg"] = entry.CelExprFunctions().RewriteProg
-			}
-		}
-		load.RewriteProg = rewriteProg
+		setupCelExpr(load, gk.loadArgs.selectors, "generic_kprobe_filter_arg")
 
 		load.MapLoad = append(load.MapLoad, getMapLoad(load, gk, uint32(index))...)
 

pkg/sensors/tracing/genericuprobe.go

@@ -19,7 +19,6 @@ import (
 	"github.com/cilium/ebpf"
 	lru "github.com/hashicorp/golang-lru/v2"
 
-	"github.com/cilium/tetragon/pkg/celbpf"
 	"github.com/cilium/tetragon/pkg/cgtracker"
 
 	"github.com/cilium/tetragon/pkg/asm"
@@ -203,13 +202,7 @@ func handleGenericUprobe(r *bytes.Reader) ([]observer.Event, error) {
 func loadSingleUprobeSensor(uprobeEntry *genericUprobe, args sensors.LoadProbeArgs) error {
 	load := args.Load
 
-	rewriteProg := make(map[string]func(prog *ebpf.ProgramSpec) error)
-	if entry := uprobeEntry.loadArgs.selectors.entry; entry != nil {
-		if celbpf.EnabledInBPF() {
-			rewriteProg["generic_uprobe_filter_arg"] = entry.CelExprFunctions().RewriteProg
-		}
-	}
-	load.RewriteProg = rewriteProg
+	setupCelExpr(load, uprobeEntry.loadArgs.selectors, "generic_uprobe_filter_arg")
 
 	// config_map data
 	var configData bytes.Buffer
@@ -318,15 +311,7 @@ func loadMultiUprobeSensor(ids []idtable.EntryID, args sensors.LoadProbeArgs) er
 			return errors.New("failed to match id")
 		}
 
-		rewriteProg := make(map[string]func(prog *ebpf.ProgramSpec) error)
-
-		if entry := uprobeEntry.loadArgs.selectors.entry; entry != nil {
-			if celbpf.EnabledInBPF() {
-				rewriteProg["generic_uprobe_filter_arg"] = entry.CelExprFunctions().RewriteProg
-			}
-		}
-
-		load.RewriteProg = rewriteProg
+		setupCelExpr(load, uprobeEntry.loadArgs.selectors, "generic_uprobe_filter_arg")
 
 		// config_map data
 		var configData bytes.Buffer