Handle unknown flags for openat2

Amp-Thread-ID: https://ampcode.com/threads/T-019c7faf-baaa-704f-af15-8aeba9df4628
Co-authored-by: Amp <amp@ampcode.com>

3 files changed, 26 insertions, 14 deletions

diff --git a/FIXES.md b/FIXES.md
new file mode 100644
index 0000000..0bd8700
--- /dev/null
+++ b/FIXES.md
@@ -0,0 +1,5 @@
+## Plan
+1. Prevent `openat2` file tracking from panicking on unknown flags by allowing `-1` (unknown) flags in userland and covering it with a focused test.
+2. Decide whether to enable `name_to_handle_at`/`open_by_handle_at` tracing or remove the correlation logic if the tracepoints stay excluded.
+3. Add `close_range` handling that removes all fds in the range from the fd table.
+4. Improve `io_uring_*` attribution by correlating setup/enter operations with returned fds or otherwise marking them as non-file-backed operations.
diff --git a/internal/file/file.go b/internal/file/file.go
index 85894c9..ff8dae2 100644
--- a/internal/file/file.go
+++ b/internal/file/file.go
@@ -24,15 +24,15 @@ type FdFile struct {
 }
 
 func NewFd(fd int32, name string, flags int32) FdFile {
-	f := FdFile{
-		fd:    fd,
-		name:  name,
-		flags: Flags(flags),
-	}
-	if f.flags == -1 {
-		panic(fmt.Sprintf("DEBUG with -1 flags: %v", f))
-	}
-	return f
+        f := FdFile{
+                fd:    fd,
+                name:  name,
+                flags: Flags(flags),
+        }
+        if f.flags == -1 {
+                f.flags = unknownFlag
+        }
+        return f
 }
 
 func NewFdWithPid(fd int32, pid uint32) (f FdFile) {
diff --git a/internal/file/file_test.go b/internal/file/file_test.go
index 22610ea..726de5a 100644
--- a/internal/file/file_test.go
+++ b/internal/file/file_test.go
@@ -6,10 +6,17 @@ import (
 )
 
 func TestStringValue(t *testing.T) {
-	var array [128]byte
-	copy(array[:], "test string")
+        var array [128]byte
+        copy(array[:], "test string")
 
-	if str := types.StringValue(array[:]); str != "test string" {
-		t.Errorf("epxected 'test string' but got '%s' with bytes '%v'", str, []byte(str))
-	}
+        if str := types.StringValue(array[:]); str != "test string" {
+                t.Errorf("epxected 'test string' but got '%s' with bytes '%v'", str, []byte(str))
+        }
+}
+
+func TestNewFdUnknownFlags(t *testing.T) {
+        fdFile := NewFd(1, "test.txt", -1)
+        if fdFile.Flags() != unknownFlag {
+                t.Errorf("expected unknown flags, got %v", fdFile.Flags())
+        }
 }