no need of debugfs package.

older kernels may not have some of the tracepoints.

2 files changed, 3 insertions, 62 deletions

diff --git a/internal/debugfs/debugfs.go b/internal/debugfs/debugfs.go
deleted file mode 100644
index 80ac436..0000000
--- a/internal/debugfs/debugfs.go
+++ /dev/null
@@ -1,57 +0,0 @@
-package debugfs
-
-import (
-	"bufio"
-	"fmt"
-	"os"
-	"path/filepath"
-	"strings"
-)
-
-// Return tracepoints with 'unsigned int fd', which are I/O tracepoints on FDs
-func TracepointsWithFd() ([]string, error) {
-	return tracepointsWith("unsigned int fd")
-}
-
-func tracepointsWith(field string) ([]string, error) {
-	var tracepoints []string
-
-	matches, err := filepath.Glob("/sys/kernel/debug/tracing/events/syscalls/*/format")
-	if err != nil {
-		return tracepoints, err
-	}
-	if len(matches) == 0 {
-		return tracepoints, fmt.Errorf("Unable to gather tracepoints with FDs")
-	}
-
-	for _, formatPath := range matches {
-		has, err := hasField(formatPath, field)
-		if err != nil {
-			return tracepoints, err
-		}
-		if !has {
-			continue
-		}
-		tracepoints = append(tracepoints, filepath.Base(filepath.Dir(formatPath)))
-	}
-
-	return tracepoints, nil
-}
-
-func hasField(formatPath, field string) (bool, error) {
-	file, err := os.Open(formatPath)
-	if err != nil {
-		return false, err
-	}
-	defer file.Close()
-
-	scanner := bufio.NewScanner(file)
-	for scanner.Scan() {
-		line := scanner.Text()
-		if strings.Contains(line, fmt.Sprintf("field:%s;", field)) {
-			return true, nil
-		}
-	}
-
-	return false, nil
-}
diff --git a/internal/ioriotng.go b/internal/ioriotng.go
index d252030..46cc0e5 100644
--- a/internal/ioriotng.go
+++ b/internal/ioriotng.go
@@ -5,7 +5,6 @@ import "C"
 import (
 	"fmt"
 
-	"ioriotng/internal/debugfs"
 	"ioriotng/internal/flags"
 	"ioriotng/internal/generated/tracepoints"
 
@@ -21,7 +20,9 @@ func attachTracepoints(bpfModule *bpf.Module) error {
 		fmt.Println("Attached prog handle_" + name)
 
 		if _, err = prog.AttachTracepoint("syscalls", name); err != nil {
-			return fmt.Errorf("Failed to attach to %s tracepoint: %v", name, err)
+			// OK, older Kernel versions may not have this tracepoint!
+			fmt.Println(fmt.Errorf("Failed to attach to %s tracepoint: %v", name, err))
+			continue
 		}
 		fmt.Println("Attached tracepoint " + name)
 	}
@@ -30,9 +31,6 @@ func attachTracepoints(bpfModule *bpf.Module) error {
 }
 
 func Run(flags flags.Flags) {
-	// Print out tracepoints with fd to consider for implementation!
-	fmt.Println(debugfs.TracepointsWithFd())
-
 	bpfModule, err := bpf.NewModuleFromFile("ioriotng.bpf.o")
 	if err != nil {
 		panic(err)