make ioriotng able to run without .c source files present

4 files changed, 36 insertions, 78 deletions

diff --git a/.gitignore b/.gitignore
index bb65147..95947f5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,4 @@ ioriotng
 /ioriotng.bpf.c
 *.o
 vmlinux.h
-
+tracepoint_list.go
diff --git a/Makefile b/Makefile
index 19460a8..8dc859e 100644
--- a/Makefile
+++ b/Makefile
@@ -14,8 +14,19 @@ bpfbuild:
 	make -C ./internal/c redo
 	if [ ! -e ioriotng.bpf.o ]; then cp -v ./internal/c/ioriotng.bpf.o .; fi
 
+.PHONY: tracepoint_list.go
+tracepoint_list.go:
+	# Fetch tracepoint probes from C code and generate list for Go userland code to auto-attach to.
+	echo "// Auto-generated from C, don't change manually!" > ./internal/tracepoints/tracepoint_list.go
+	echo 'package tracepoints' >> ./internal/tracepoints/tracepoint_list.go
+	echo >> ./internal/tracepoints/tracepoint_list.go
+	echo 'var tracepointList = []string{' >> ./internal/tracepoints/tracepoint_list.go
+	sed -n -E '/^SEC.*sys_(enter|exit)_/ { s/[")]//g; s/.*sys_(.*)/\t"\1",/; p; }' \
+		./internal/c/tracepoints/*.c >> ./internal/tracepoints/tracepoint_list.go
+	echo '}' >> ./internal/tracepoints/tracepoint_list.go
+
 .PHONY: gobuild
-gobuild:
+gobuild: tracepoint_list.go
 	go build -tags netgo -ldflags '-w -extldflags "-static"' -o ioriotng ./cmd/ioriotng/main.go
 
 .PHONY: clean
diff --git a/internal/tracepoints/syscalls.go b/internal/tracepoints/syscalls.go
deleted file mode 100644
index ccc4f58..0000000
--- a/internal/tracepoints/syscalls.go
+++ /dev/null
@@ -1,76 +0,0 @@
-package tracepoints
-
-import (
-	"fmt"
-	"os"
-	"regexp"
-	"strings"
-
-	bpf "github.com/aquasecurity/libbpfgo"
-)
-
-// SEC("tracepoint/syscalls/sys_exit_openat")
-var syscallRe = regexp.MustCompile(`sys_((enter|exit).*)"\)`)
-
-func filterLines(lines []string) ([]string, error) {
-	var syscalls []string
-
-	for _, line := range lines {
-		matches := syscallRe.FindStringSubmatch(line)
-		if len(matches) < 1 {
-			continue
-		}
-		syscalls = append(syscalls, matches[1])
-	}
-
-	return syscalls, nil
-}
-
-// Filter out all used syscall tracepoints from *.bpf.c
-func tracedSyscalls() ([]string, error) {
-	var syscalls []string
-	const syscallDir = "internal/c/tracepoints"
-
-	files, err := os.ReadDir(syscallDir)
-	if err != nil {
-		return syscalls, err
-	}
-
-	for _, file := range files {
-		fileName := file.Name()
-		if !strings.HasSuffix(fileName, ".c") {
-			continue
-		}
-		content, err := os.ReadFile(fmt.Sprintf("%s/%s", syscallDir, fileName))
-		if err != nil {
-			return syscalls, err
-		}
-		syscalls_, err := filterLines(strings.Split(string(content), "\n"))
-		if err != nil {
-			return syscalls, err
-		}
-		syscalls = append(syscalls, syscalls_...)
-	}
-
-	return syscalls, nil
-}
-
-func AttachSyscalls(bpfModule *bpf.Module) error {
-	syscalls, err := tracedSyscalls()
-	if err != nil {
-		return err
-	}
-	for _, name := range syscalls {
-		// Attach to tracepoint
-		prog, err := bpfModule.GetProgram(fmt.Sprintf("handle_%s", name))
-		if err != nil {
-			return fmt.Errorf("Failed to get BPF program handle_%s: %v", name, err)
-		}
-		fmt.Println("Attached prog handle_" + name)
-		if _, err = prog.AttachTracepoint("syscalls", fmt.Sprintf("sys_%s", name)); err != nil {
-			return fmt.Errorf("Failed to attach to sys_%s tracepoint: %v", name, err)
-		}
-		fmt.Println("Attached tracepoint sys_" + name)
-	}
-	return nil
-}
diff --git a/internal/tracepoints/tracepoints.go b/internal/tracepoints/tracepoints.go
new file mode 100644
index 0000000..1b6cf56
--- /dev/null
+++ b/internal/tracepoints/tracepoints.go
@@ -0,0 +1,23 @@
+package tracepoints
+
+import (
+	"fmt"
+
+	bpf "github.com/aquasecurity/libbpfgo"
+)
+
+func AttachSyscalls(bpfModule *bpf.Module) error {
+	for _, name := range tracepointList {
+		// Attach to tracepoint
+		prog, err := bpfModule.GetProgram(fmt.Sprintf("handle_%s", name))
+		if err != nil {
+			return fmt.Errorf("Failed to get BPF program handle_%s: %v", name, err)
+		}
+		fmt.Println("Attached prog handle_" + name)
+		if _, err = prog.AttachTracepoint("syscalls", fmt.Sprintf("sys_%s", name)); err != nil {
+			return fmt.Errorf("Failed to attach to sys_%s tracepoint: %v", name, err)
+		}
+		fmt.Println("Attached tracepoint sys_" + name)
+	}
+	return nil
+}