1 files changed, 152 insertions, 0 deletions
diff --git a/internal/generate/codegen.go b/internal/generate/codegen.go
new file mode 100644
index 0000000..9b9f52c
--- /dev/null
+++ b/internal/generate/codegen.go
@@ -0,0 +1,152 @@
+package generate
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// Syscall groups enter+exit formats by syscall name.
+type Syscall struct {
+	Name  string
+	Enter *Format
+	Exit  *Format
+}
+
+// GeneratedTracepoint holds a classified format ready for code generation.
+type GeneratedTracepoint struct {
+	Format         *Format
+	Classification ClassificationResult
+}
+
+// GenerateTracepointsC produces the full generated_tracepoints.c content from
+// concatenated sysfs format data parsed into formats.
+func GenerateTracepointsC(formats []Format) string {
+	syscalls := groupBySyscall(formats)
+	var b strings.Builder
+
+	b.WriteString("// Code generated - don't change manually!\n\n")
+
+	var accepted []GeneratedTracepoint
+	for _, sc := range syscalls {
+		tracepoints, reason := classifySyscall(sc)
+		if reason != "" {
+			fmt.Fprintf(&b, "/// %s\n", reason)
+			continue
+		}
+		accepted = append(accepted, tracepoints...)
+	}
+
+	sort.Slice(accepted, func(i, j int) bool {
+		return accepted[i].Format.ID > accepted[j].Format.ID
+	})
+
+	b.WriteString("\n")
+	for _, tp := range accepted {
+		fmt.Fprintf(&b, "#define %s %d\n", strings.ToUpper(tp.Format.Name), tp.Format.ID)
+	}
+	b.WriteString("\n")
+
+	for _, tp := range accepted {
+		b.WriteString(generateBPFHandler(tp))
+		b.WriteString("\n")
+	}
+
+	return b.String()
+}
+
+func groupBySyscall(formats []Format) []Syscall {
+	m := make(map[string]*Syscall)
+	var order []string
+
+	for i := range formats {
+		f := &formats[i]
+		parts := strings.SplitN(f.Name, "_", 3)
+		if len(parts) < 3 {
+			continue
+		}
+		enterExit := parts[1]
+		what := parts[2]
+
+		sc, ok := m[what]
+		if !ok {
+			sc = &Syscall{Name: what}
+			m[what] = sc
+			order = append(order, what)
+		}
+		if enterExit == "enter" {
+			sc.Enter = f
+		} else {
+			sc.Exit = f
+		}
+	}
+
+	result := make([]Syscall, 0, len(order))
+	for _, name := range order {
+		result = append(result, *m[name])
+	}
+	return result
+}
+
+func classifySyscall(sc Syscall) ([]GeneratedTracepoint, string) {
+	var enterClass, exitClass ClassificationResult
+	allCanGenerate := true
+
+	if sc.Enter != nil {
+		enterClass = ClassifyFormat(sc.Enter)
+		if enterClass.Kind == KindNone {
+			allCanGenerate = false
+		}
+	} else {
+		allCanGenerate = false
+	}
+
+	if sc.Exit != nil {
+		exitClass = ClassifyFormat(sc.Exit)
+		if exitClass.Kind == KindNone {
+			allCanGenerate = false
+		}
+	} else {
+		allCanGenerate = false
+	}
+
+	if !allCanGenerate {
+		names := syscallFormatNames(sc)
+		return nil, fmt.Sprintf("Ignoring %s as possibly not file I/O related", strings.Join(names, " "))
+	}
+
+	if isEnterRejected(enterClass.Kind) {
+		names := syscallFormatNames(sc)
+		return nil, fmt.Sprintf("Ignoring %s as enter-rejected", strings.Join(names, " "))
+	}
+
+	var result []GeneratedTracepoint
+	if sc.Enter != nil {
+		result = append(result, GeneratedTracepoint{Format: sc.Enter, Classification: enterClass})
+	}
+	if sc.Exit != nil {
+		result = append(result, GeneratedTracepoint{Format: sc.Exit, Classification: exitClass})
+	}
+	return result, ""
+}
+
+func isEnterRejected(kind TracepointKind) bool {
+	switch kind {
+	case KindFd, KindName, KindOpen, KindPathname, KindFcntl, KindNull, KindDup3, KindOpenByHandleAt:
+		return false
+	default:
+		return true
+	}
+}
+
+func syscallFormatNames(sc Syscall) []string {
+	var names []string
+	if sc.Enter != nil {
+		names = append(names, sc.Enter.Name)
+	}
+	if sc.Exit != nil {
+		names = append(names, sc.Exit.Name)
+	}
+	sort.Strings(names)
+	return names
+}