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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef SANDBOX_LINUX_SECCOMP_BPF_SYSCALL_ITERATOR_H__
      6 #define SANDBOX_LINUX_SECCOMP_BPF_SYSCALL_ITERATOR_H__
      7 
      8 #include <stdint.h>
      9 
     10 #include "base/macros.h"
     11 #include "sandbox/sandbox_export.h"
     12 
     13 namespace sandbox {
     14 
     15 // Iterates over the entire system call range from 0..0xFFFFFFFFu. This
     16 // iterator is aware of how system calls look like and will skip quickly
     17 // over ranges that can't contain system calls. It iterates more slowly
     18 // whenever it reaches a range that is potentially problematic, returning
     19 // the last invalid value before a valid range of system calls, and the
     20 // first invalid value after a valid range of syscalls. It iterates over
     21 // individual values whenever it is in the normal range for system calls
     22 // (typically MIN_SYSCALL..MAX_SYSCALL).
     23 // If |invalid_only| is true, this iterator will only return invalid
     24 // syscall numbers, but will still skip quickly over invalid ranges,
     25 // returning the first invalid value in the range and then skipping
     26 // to the last invalid value in the range.
     27 //
     28 // Example usage:
     29 //   for (SyscallIterator iter(false); !iter.Done(); ) {
     30 //     uint32_t sysnum = iter.Next();
     31 //     // Do something with sysnum.
     32 //   }
     33 //
     34 // TODO(markus): Make this a classic C++ iterator.
     35 class SANDBOX_EXPORT SyscallIterator {
     36  public:
     37   explicit SyscallIterator(bool invalid_only)
     38       : invalid_only_(invalid_only), done_(false), num_(0) {}
     39 
     40   bool Done() const { return done_; }
     41   uint32_t Next();
     42   static bool IsValid(uint32_t num);
     43 
     44  private:
     45   static bool IsArmPrivate(uint32_t num);
     46 
     47   bool invalid_only_;
     48   bool done_;
     49   uint32_t num_;
     50 
     51   DISALLOW_IMPLICIT_CONSTRUCTORS(SyscallIterator);
     52 };
     53 
     54 }  // namespace sandbox
     55 
     56 #endif  // SANDBOX_LINUX_SECCOMP_BPF_SYSCALL_ITERATOR_H__
     57