text: // Copyright (c) 2012 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_VERIFIER_H__
  #define SANDBOX_LINUX_SECCOMP_BPF_VERIFIER_H__
  
  #include <stdint.h>
  
  #include <vector>
  
  #include "base/macros.h"
  
  struct sock_filter;
  
  namespace sandbox {
  struct arch_seccomp_data;
  namespace bpf_dsl {
  class SandboxBPFDSLPolicy;
  class PolicyCompiler;
  }
  
  class Verifier {
   public:
    // Evaluate the BPF program for all possible inputs and verify that it
    // computes the correct result. We use the "evaluators" to determine
    // the full set of possible inputs that we have to iterate over.
    // Returns success, if the BPF filter accurately reflects the rules
    // set by the "evaluators".
    // Upon success, "err" is set to NULL. Upon failure, it contains a static
    // error message that does not need to be free()'d.
    static bool VerifyBPF(bpf_dsl::PolicyCompiler* compiler,
                          const std::vector<struct sock_filter>& program,
                          const bpf_dsl::SandboxBPFDSLPolicy& policy,
                          const char** err);
  
    // Evaluate a given BPF program for a particular set of system call
    // parameters. If evaluation failed for any reason, "err" will be set to
    // a non-NULL error string. Otherwise, the BPF program's result will be
    // returned by the function and "err" is NULL.
    // We do not actually implement the full BPF state machine, but only the
    // parts that can actually be generated by our BPF compiler. If this code
    // is used for purposes other than verifying the output of the sandbox's
    // BPF compiler, we might have to extend this BPF interpreter.
    static uint32_t EvaluateBPF(const std::vector<struct sock_filter>& program,
                                const struct arch_seccomp_data& data,
                                const char** err);
  
   private:
    DISALLOW_IMPLICIT_CONSTRUCTORS(Verifier);
  };
  
  }  // namespace sandbox
  
  #endif  // SANDBOX_LINUX_SECCOMP_BPF_VERIFIER_H__
  