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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 namespace playground2 {
     11 
     12 // Iterates over the entire system call range from 0..0xFFFFFFFFu. This
     13 // iterator is aware of how system calls look like and will skip quickly
     14 // over ranges that can't contain system calls. It iterates more slowly
     15 // whenever it reaches a range that is potentially problematic, returning
     16 // the last invalid value before a valid range of system calls, and the
     17 // first invalid value after a valid range of syscalls. It iterates over
     18 // individual values whenever it is in the normal range for system calls
     19 // (typically MIN_SYSCALL..MAX_SYSCALL).
     20 // If |invalid_only| is true, this iterator will only return invalid
     21 // syscall numbers, but will still skip quickly over invalid ranges,
     22 // returning the first invalid value in the range and then skipping
     23 // to the last invalid value in the range.
     24 //
     25 // Example usage:
     26 //   for (SyscallIterator iter(false); !iter.Done(); ) {
     27 //     uint32_t sysnum = iter.Next();
     28 //     // Do something with sysnum.
     29 //   }
     30 //
     31 // TODO(markus): Make this a classic C++ iterator.
     32 class SyscallIterator {
     33  public:
     34   explicit SyscallIterator(bool invalid_only)
     35       : invalid_only_(invalid_only),
     36         done_(false),
     37         num_(0) {}
     38 
     39   bool Done() const { return done_; }
     40   uint32_t Next();
     41   static bool IsValid(uint32_t num);
     42 
     43  private:
     44   static bool IsArmPrivate(uint32_t num);
     45 
     46   bool     invalid_only_;
     47   bool     done_;
     48   uint32_t num_;
     49 
     50   DISALLOW_IMPLICIT_CONSTRUCTORS(SyscallIterator);
     51 };
     52 
     53 }  // namespace playground2
     54 
     55 #endif  // SANDBOX_LINUX_SECCOMP_BPF_SYSCALL_ITERATOR_H__
     56 
     57