remove redundant guards and fix potential bugs

Signed-off-by: kwakubiney <kebiney@hotmail.com>
cilium · Jul 3, 2023 · fe0b65a · fe0b65a
1 parent 5ef8223
commit fe0b65a
Show file tree

Hide file tree

Showing 5 changed files with 23 additions and 38 deletions.
diff --git a/elf_reader_test.go b/elf_reader_test.go
@@ -212,6 +212,7 @@ func TestLoadCollectionSpec(t *testing.T) {
 				LogLevel: LogLevelBranch,
 			},
 		})
+
 		testutils.SkipIfNotSupported(t, err)
 		if err != nil {
 			t.Fatal(err)

diff --git a/link/syscalls.go b/link/syscalls.go
@@ -47,6 +47,10 @@ var haveProgAttach = internal.NewFeatureTest("BPF_PROG_ATTACH", "4.10", func() e
 })
 
 var haveProgAttachReplace = internal.NewFeatureTest("BPF_PROG_ATTACH atomic replacement of MULTI progs", "5.5", func() error {
+	if err := haveProgAttach(); err != nil {
+		return err
+	}
+
 	prog, err := ebpf.NewProgram(&ebpf.ProgramSpec{
 		Type:       ebpf.CGroupSKB,
 		AttachType: ebpf.AttachCGroupInetIngress,
@@ -56,12 +60,11 @@ var haveProgAttachReplace = internal.NewFeatureTest("BPF_PROG_ATTACH atomic repl
 			asm.Return(),
 		},
 	})
-	if err != nil {
-		if errors.Is(err, unix.EINVAL) {
-			return internal.ErrNotSupported
-		}
-		return err
+
+	if errors.Is(err, unix.EINVAL) {
+		return internal.ErrNotSupported
 	}
+
 	defer prog.Close()
 
 	// We know that we have BPF_PROG_ATTACH since we can load CGroupSKB programs.
@@ -85,10 +88,6 @@ var haveProgAttachReplace = internal.NewFeatureTest("BPF_PROG_ATTACH atomic repl
 		if errors.Is(err, unix.EBADF) {
 			return nil
 		}
-
-		if haveFeatErr := haveProgAttach(); haveFeatErr != nil {
-			return haveFeatErr
-		}
 	}
 	return err
 })

diff --git a/link/uprobe.go b/link/uprobe.go
@@ -4,7 +4,6 @@ import (
 	"debug/elf"
 	"errors"
 	"fmt"
-	"github.com/cilium/ebpf/internal/unix"
 	"os"
 	"sync"
 
@@ -20,7 +19,7 @@ var (
 	haveRefCtrOffsetPMU     = internal.NewFeatureTest("RefCtrOffsetPMU", "4.20", func() error {
 		_, err := os.Stat(uprobeRefCtrOffsetPMUPath)
 		if err != nil {
-			if errors.Is(err, unix.EINVAL) {
+			if errors.Is(err, os.ErrNotExist) {
 				return internal.ErrNotSupported
 			}
 			return err

diff --git a/map.go b/map.go
@@ -436,16 +436,17 @@ func (spec *MapSpec) createMap(inner *sys.FD, opts MapOptions) (_ *Map, err erro
 		if errors.Is(err, unix.EINVAL) && spec.Type == UnspecifiedMap {
 			return nil, fmt.Errorf("map create: cannot use type %s", UnspecifiedMap)
 		}
-		if attr.BtfFd == 0 {
-			return nil, fmt.Errorf("map create: %w (without BTF k/v)", err)
-		}
 
 		if spec.Flags&(unix.BPF_F_RDONLY_PROG|unix.BPF_F_WRONLY_PROG) > 0 || spec.Freeze {
 			if haveFeatErr := haveMapMutabilityModifiers(); err != nil {
 				return nil, fmt.Errorf("map create: %w", haveFeatErr)
 			}
 		}
 
+		if attr.BtfFd == 0 {
+			return nil, fmt.Errorf("map create: %w (without BTF k/v)", err)
+		}
+
 		if spec.Flags&unix.BPF_F_MMAPABLE > 0 {
 			if haveFeatErr := haveMmapableMaps(); err != nil {
 				return nil, fmt.Errorf("map create: %w", haveFeatErr)

diff --git a/syscalls.go b/syscalls.go
@@ -87,12 +87,11 @@ var haveMapMutabilityModifiers = internal.NewFeatureTest("read- and write-only m
 		MaxEntries: 1,
 		MapFlags:   unix.BPF_F_RDONLY_PROG,
 	})
+
 	if err != nil {
-		if errors.Is(err, unix.EINVAL) {
-			return internal.ErrNotSupported
-		}
-		return err
+		return internal.ErrNotSupported
 	}
+
 	_ = m.Close()
 	return nil
 })
@@ -107,10 +106,7 @@ var haveMmapableMaps = internal.NewFeatureTest("mmapable maps", "5.5", func() er
 		MapFlags:   unix.BPF_F_MMAPABLE,
 	})
 	if err != nil {
-		if errors.Is(err, unix.EINVAL) {
-			return internal.ErrNotSupported
-		}
-		return err
+		return internal.ErrNotSupported
 	}
 	_ = m.Close()
 	return nil
@@ -145,11 +141,9 @@ var haveNoPreallocMaps = internal.NewFeatureTest("prealloc maps", "4.6", func()
 		MaxEntries: 1,
 		MapFlags:   unix.BPF_F_NO_PREALLOC,
 	})
+
 	if err != nil {
-		if errors.Is(err, unix.EINVAL) {
-			return internal.ErrNotSupported
-		}
-		return err
+		return internal.ErrNotSupported
 	}
 	_ = m.Close()
 	return nil
@@ -191,10 +185,7 @@ var haveObjName = internal.NewFeatureTest("object names", "4.15", func() error {
 	fd, err := sys.MapCreate(&attr)
 
 	if err != nil {
-		if errors.Is(err, unix.EINVAL) {
-			return internal.ErrNotSupported
-		}
-		return err
+		return internal.ErrNotSupported
 	}
 
 	_ = fd.Close()
@@ -216,10 +207,7 @@ var objNameAllowsDot = internal.NewFeatureTest("dot in object names", "5.2", fun
 
 	fd, err := sys.MapCreate(&attr)
 	if err != nil {
-		if errors.Is(err, unix.EINVAL) {
-			return internal.ErrNotSupported
-		}
-		return err
+		return internal.ErrNotSupported
 	}
 
 	_ = fd.Close()
@@ -238,10 +226,7 @@ var haveBatchAPI = internal.NewFeatureTest("map batch api", "5.6", func() error
 	fd, err := sys.MapCreate(&attr)
 
 	if err != nil {
-		if errors.Is(err, unix.EINVAL) {
-			return internal.ErrNotSupported
-		}
-		return err
+		return internal.ErrNotSupported
 	}
 	defer fd.Close()