diff --git a/pkg/osutil/osutil.go b/pkg/osutil/osutil.go
index cd6a1cce..b50b6e45 100644
--- a/pkg/osutil/osutil.go
+++ b/pkg/osutil/osutil.go
@@ -130,11 +130,12 @@ func IsAccessible(name string) error {
 // FilesExist returns true if all files exist in dir.
 // Files are assumed to be relative names in slash notation.
 func FilesExist(dir string, files map[string]bool) bool {
-	for f, required := range files {
+	for pattern, required := range files {
 		if !required {
 			continue
 		}
-		if !IsExist(filepath.Join(dir, filepath.FromSlash(f))) {
+		files, err := filepath.Glob(filepath.Join(dir, filepath.FromSlash(pattern)))
+		if err != nil || len(files) == 0 {
 			return false
 		}
 	}
@@ -154,7 +155,18 @@ func CopyFiles(srcDir, dstDir string, files map[string]bool) error {
 	if err := MkdirAll(tmpDir); err != nil {
 		return err
 	}
+	if err := foreachPatternFile(srcDir, tmpDir, files, CopyFile); err != nil {
+		return err
+	}
+	if err := os.RemoveAll(dstDir); err != nil {
+		return err
+	}
+	return os.Rename(tmpDir, dstDir)
+}
+
+func foreachPatternFile(srcDir, dstDir string, files map[string]bool, fn func(src, dst string) error) error {
 	srcDir = filepath.Clean(srcDir)
+	dstDir = filepath.Clean(dstDir)
 	for pattern, required := range files {
 		files, err := filepath.Glob(filepath.Join(srcDir, filepath.FromSlash(pattern)))
 		if err != nil {
@@ -170,19 +182,16 @@ func CopyFiles(srcDir, dstDir string, files map[string]bool) error {
 			if !strings.HasPrefix(file, srcDir) {
 				return fmt.Errorf("file %q matched from %q in %q doesn't have src prefix", file, pattern, srcDir)
 			}
-			dst := filepath.Join(tmpDir, strings.TrimPrefix(file, srcDir))
+			dst := filepath.Join(dstDir, strings.TrimPrefix(file, srcDir))
 			if err := MkdirAll(filepath.Dir(dst)); err != nil {
 				return err
 			}
-			if err := CopyFile(file, dst); err != nil {
+			if err := fn(file, dst); err != nil {
 				return err
 			}
 		}
 	}
-	if err := os.RemoveAll(dstDir); err != nil {
-		return err
-	}
-	return os.Rename(tmpDir, dstDir)
+	return nil
 }
 
 func CopyDirRecursively(srcDir, dstDir string) error {
@@ -219,20 +228,7 @@ func LinkFiles(srcDir, dstDir string, files map[string]bool) error {
 	if err := MkdirAll(dstDir); err != nil {
 		return err
 	}
-	for f, required := range files {
-		src := filepath.Join(srcDir, filepath.FromSlash(f))
-		if !required && !IsExist(src) {
-			continue
-		}
-		dst := filepath.Join(dstDir, filepath.FromSlash(f))
-		if err := MkdirAll(filepath.Dir(dst)); err != nil {
-			return err
-		}
-		if err := os.Link(src, dst); err != nil {
-			return err
-		}
-	}
-	return nil
+	return foreachPatternFile(srcDir, dstDir, files, os.Link)
 }
 
 func MkdirAll(dir string) error {
diff --git a/pkg/osutil/osutil_test.go b/pkg/osutil/osutil_test.go
index 3d367a0c..168e7ba3 100644
--- a/pkg/osutil/osutil_test.go
+++ b/pkg/osutil/osutil_test.go
@@ -73,42 +73,53 @@ func TestCopyFiles(t *testing.T) {
 			},
 		},
 	}
-	for i, test := range tests {
-		t.Run(fmt.Sprint(i), func(t *testing.T) {
-			dir, err := ioutil.TempDir("", "syz-osutil-test")
-			if err != nil {
-				t.Fatal(err)
-			}
-			defer os.RemoveAll(dir)
-			src := filepath.Join(dir, "src")
-			dst := filepath.Join(dir, "dst")
-			for _, file := range test.files {
-				file = filepath.Join(src, filepath.FromSlash(file))
-				if err := MkdirAll(filepath.Dir(file)); err != nil {
-					t.Fatal(err)
-				}
-				if err := WriteFile(file, []byte{'a'}); err != nil {
-					t.Fatal(err)
-				}
-			}
-			if err := CopyFiles(src, dst, test.patterns); err != nil {
-				if test.err != "" {
-					if strings.Contains(err.Error(), test.err) {
-						return
+	for _, link := range []bool{false, true} {
+		fn, fnName := CopyFiles, "CopyFiles"
+		if link {
+			fn, fnName = LinkFiles, "LinkFiles"
+		}
+		t.Run(fnName, func(t *testing.T) {
+			for i, test := range tests {
+				t.Run(fmt.Sprint(i), func(t *testing.T) {
+					dir, err := ioutil.TempDir("", "syz-osutil-test")
+					if err != nil {
+						t.Fatal(err)
 					}
-					t.Fatalf("got err %q, want %q", err, test.err)
-				}
-				t.Fatal(err)
-			} else if test.err != "" {
-				t.Fatalf("got no err, want %q", test.err)
-			}
-			if err := os.RemoveAll(src); err != nil {
-				t.Fatal(err)
-			}
-			for _, file := range test.files {
-				if !IsExist(filepath.Join(dst, filepath.FromSlash(file))) {
-					t.Fatalf("%v does not exist in dst", file)
-				}
+					defer os.RemoveAll(dir)
+					src := filepath.Join(dir, "src")
+					dst := filepath.Join(dir, "dst")
+					for _, file := range test.files {
+						file = filepath.Join(src, filepath.FromSlash(file))
+						if err := MkdirAll(filepath.Dir(file)); err != nil {
+							t.Fatal(err)
+						}
+						if err := WriteFile(file, []byte{'a'}); err != nil {
+							t.Fatal(err)
+						}
+					}
+					if err := fn(src, dst, test.patterns); err != nil {
+						if test.err != "" {
+							if strings.Contains(err.Error(), test.err) {
+								return
+							}
+							t.Fatalf("got err %q, want %q", err, test.err)
+						}
+						t.Fatal(err)
+					} else if test.err != "" {
+						t.Fatalf("got no err, want %q", test.err)
+					}
+					if err := os.RemoveAll(src); err != nil {
+						t.Fatal(err)
+					}
+					for _, file := range test.files {
+						if !IsExist(filepath.Join(dst, filepath.FromSlash(file))) {
+							t.Fatalf("%v does not exist in dst", file)
+						}
+					}
+					if !FilesExist(dst, test.patterns) {
+						t.Fatalf("dst files don't exist after copy")
+					}
+				})
 			}
 		})
 	}