Linux sandbox: implement new BPF testing macros

sandbox/linux/seccomp-bpf/bpf_tester_compatibility_delegate.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SANDBOX_LINUX_SECCOMP_BPF_BPF_TESTER_COMPATIBILITY_DELEGATE_H_
+#define SANDBOX_LINUX_SECCOMP_BPF_BPF_TESTER_COMPATIBILITY_DELEGATE_H_
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "base/memory/scoped_ptr.h"
+#include "sandbox/linux/seccomp-bpf/sandbox_bpf_compatibility_policy.h"
+#include "sandbox/linux/seccomp-bpf/sandbox_bpf_test_runner.h"
+#include "sandbox/linux/tests/sandbox_test_runner.h"
+#include "sandbox/linux/tests/unit_tests.h"
+
+namespace sandbox {
+
+// This templated class allows building a BPFTesterDelegate from a
+// deprecated-style BPF policy (that is a SyscallEvaluator function pointer,
+// instead of a SandboxBPFPolicy class), specified in |policy_function| and a
+// function pointer to a test in |test_function|.
+// This allows both the policy and the test function to take a pointer to an
+// object of type "Aux" as a parameter. This is used to implement the BPF_TEST
+// macro and should generally not be used directly.
+template <class Aux = void>
+class BPFTesterCompatibilityDelegate : public BPFTesterDelegate {
+ public:
+  typedef Aux AuxType;
+  BPFTesterCompatibilityDelegate(
+      void (*test_function)(AuxType*),
+      typename CompatibilityPolicy<AuxType>::SyscallEvaluator policy_function)
+      : aux_pointer_for_policy_(NULL),
+        test_function_(test_function),
+        policy_function_(policy_function) {
+    // This will be NULL iff AuxType is void.
+    aux_pointer_for_policy_ = NewAux();
+  }
+
+  virtual ~BPFTesterCompatibilityDelegate() {
+    DeleteAux(aux_pointer_for_policy_);
+  }
+
+  virtual scoped_ptr<SandboxBPFPolicy> GetSandboxBPFPolicy() OVERRIDE {
+    // The current method is guaranteed to only run in the child process
+    // running the test. In this process, the current object is guaranteed
+    // to live forever. So it's ok to pass aux_pointer_for_policy_ to
+    // the policy, which could in turn pass it to the kernel via Trap().
+    return scoped_ptr<SandboxBPFPolicy>(new CompatibilityPolicy<AuxType>(
+        policy_function_, aux_pointer_for_policy_));
+  }
+
+  virtual void RunTestFunction() OVERRIDE {
+    // Run the actual test.
+    // The current object is guaranteed to live forever in the child process
+    // where this will run.
+    test_function_(aux_pointer_for_policy_);
+  }
+
+ private:
+  // Allocate an object of type Aux. This is specialized to return NULL when
+  // trying to allocate a void.
+  static Aux* NewAux() { return new Aux(); }
+  static void DeleteAux(Aux* aux) { delete aux; }
+
+  AuxType* aux_pointer_for_policy_;
+  void (*test_function_)(AuxType*);
+  typename CompatibilityPolicy<AuxType>::SyscallEvaluator policy_function_;
+  DISALLOW_COPY_AND_ASSIGN(BPFTesterCompatibilityDelegate);
+};
+
+// Specialization of NewAux that returns NULL;
+template <>
+void* BPFTesterCompatibilityDelegate<void>::NewAux();
+template <>
+void BPFTesterCompatibilityDelegate<void>::DeleteAux(void* aux);
+
+}  // namespace sandbox
+
+#endif  // SANDBOX_LINUX_SECCOMP_BPF_BPF_TESTER_COMPATIBILITY_DELEGATE_H_