Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 157 insertions, 0 deletions

diff --git a/pkg/bpf/program_builder_test.go b/pkg/bpf/program_builder_test.go
new file mode 100644
index 000000000..7e4f06584
--- /dev/null
+++ b/pkg/bpf/program_builder_test.go
@@ -0,0 +1,157 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package bpf
+
+import (
+	"fmt"
+	"testing"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+)
+
+func validate(p *ProgramBuilder, expected []linux.BPFInstruction) error {
+	instructions, err := p.Instructions()
+	if err != nil {
+		return fmt.Errorf("Instructions() failed: %v", err)
+	}
+	got, err := DecodeProgram(instructions)
+	if err != nil {
+		return fmt.Errorf("DecodeProgram('instructions') failed: %v", err)
+	}
+	expectedDecoded, err := DecodeProgram(expected)
+	if err != nil {
+		return fmt.Errorf("DecodeProgram('expected') failed: %v", err)
+	}
+	if got != expectedDecoded {
+		return fmt.Errorf("DecodeProgram() failed, expected: %q, got: %q", expectedDecoded, got)
+	}
+	return nil
+}
+
+func TestProgramBuilderSimple(t *testing.T) {
+	p := NewProgramBuilder()
+	p.AddStmt(Ld+Abs+W, 10)
+	p.AddJump(Jmp+Ja, 10, 0, 0)
+
+	expected := []linux.BPFInstruction{
+		Stmt(Ld+Abs+W, 10),
+		Jump(Jmp+Ja, 10, 0, 0),
+	}
+
+	if err := validate(p, expected); err != nil {
+		t.Errorf("Validate() failed: %v", err)
+	}
+}
+
+func TestProgramBuilderLabels(t *testing.T) {
+	p := NewProgramBuilder()
+	p.AddJumpTrueLabel(Jmp+Jeq+K, 11, "label_1", 0)
+	p.AddJumpFalseLabel(Jmp+Jeq+K, 12, 0, "label_2")
+	p.AddJumpLabels(Jmp+Jeq+K, 13, "label_3", "label_4")
+	if err := p.AddLabel("label_1"); err != nil {
+		t.Errorf("AddLabel(label_1) failed: %v", err)
+	}
+	p.AddStmt(Ld+Abs+W, 1)
+	if err := p.AddLabel("label_3"); err != nil {
+		t.Errorf("AddLabel(label_3) failed: %v", err)
+	}
+	p.AddJumpLabels(Jmp+Jeq+K, 14, "label_4", "label_5")
+	if err := p.AddLabel("label_2"); err != nil {
+		t.Errorf("AddLabel(label_2) failed: %v", err)
+	}
+	p.AddJumpLabels(Jmp+Jeq+K, 15, "label_4", "label_6")
+	if err := p.AddLabel("label_4"); err != nil {
+		t.Errorf("AddLabel(label_4) failed: %v", err)
+	}
+	p.AddStmt(Ld+Abs+W, 4)
+	if err := p.AddLabel("label_5"); err != nil {
+		t.Errorf("AddLabel(label_5) failed: %v", err)
+	}
+	if err := p.AddLabel("label_6"); err != nil {
+		t.Errorf("AddLabel(label_6) failed: %v", err)
+	}
+	p.AddStmt(Ld+Abs+W, 5)
+
+	expected := []linux.BPFInstruction{
+		Jump(Jmp+Jeq+K, 11, 2, 0),
+		Jump(Jmp+Jeq+K, 12, 0, 3),
+		Jump(Jmp+Jeq+K, 13, 1, 3),
+		Stmt(Ld+Abs+W, 1),
+		Jump(Jmp+Jeq+K, 14, 1, 2),
+		Jump(Jmp+Jeq+K, 15, 0, 1),
+		Stmt(Ld+Abs+W, 4),
+		Stmt(Ld+Abs+W, 5),
+	}
+	if err := validate(p, expected); err != nil {
+		t.Errorf("Validate() failed: %v", err)
+	}
+	// Calling validate()=>p.Instructions() again to make sure
+	// Instructions can be called multiple times without ruining
+	// the program.
+	if err := validate(p, expected); err != nil {
+		t.Errorf("Validate() failed: %v", err)
+	}
+}
+
+func TestProgramBuilderMissingErrorTarget(t *testing.T) {
+	p := NewProgramBuilder()
+	p.AddJumpTrueLabel(Jmp+Jeq+K, 10, "label_1", 0)
+	if _, err := p.Instructions(); err == nil {
+		t.Errorf("Instructions() should have failed")
+	}
+}
+
+func TestProgramBuilderLabelWithNoInstruction(t *testing.T) {
+	p := NewProgramBuilder()
+	p.AddJumpTrueLabel(Jmp+Jeq+K, 10, "label_1", 0)
+	if err := p.AddLabel("label_1"); err != nil {
+		t.Errorf("AddLabel(label_1) failed: %v", err)
+	}
+	if _, err := p.Instructions(); err == nil {
+		t.Errorf("Instructions() should have failed")
+	}
+}
+
+func TestProgramBuilderUnusedLabel(t *testing.T) {
+	p := NewProgramBuilder()
+	if err := p.AddLabel("unused"); err == nil {
+		t.Errorf("AddLabel(unused) should have failed")
+	}
+}
+
+func TestProgramBuilderLabelAddedTwice(t *testing.T) {
+	p := NewProgramBuilder()
+	p.AddJumpTrueLabel(Jmp+Jeq+K, 10, "label_1", 0)
+	if err := p.AddLabel("label_1"); err != nil {
+		t.Errorf("AddLabel(label_1) failed: %v", err)
+	}
+	p.AddStmt(Ld+Abs+W, 0)
+	if err := p.AddLabel("label_1"); err == nil {
+		t.Errorf("AddLabel(label_1) failed: %v", err)
+	}
+}
+
+func TestProgramBuilderJumpBackwards(t *testing.T) {
+	p := NewProgramBuilder()
+	p.AddJumpTrueLabel(Jmp+Jeq+K, 10, "label_1", 0)
+	if err := p.AddLabel("label_1"); err != nil {
+		t.Errorf("AddLabel(label_1) failed: %v", err)
+	}
+	p.AddStmt(Ld+Abs+W, 0)
+	p.AddJumpTrueLabel(Jmp+Jeq+K, 10, "label_1", 0)
+	if _, err := p.Instructions(); err == nil {
+		t.Errorf("Instructions() should have failed")
+	}
+}