Update from chromium 62675d9fb31fb8cedc40f68e78e8445a74f362e7

sandbox/linux/seccomp-bpf/syscall_iterator.h

+// 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_SYSCALL_ITERATOR_H__
+#define SANDBOX_LINUX_SECCOMP_BPF_SYSCALL_ITERATOR_H__
+
+#include <stdint.h>
+
+#include "base/macros.h"
+#include "sandbox/sandbox_export.h"
+
+namespace sandbox {
+
+// TODO(mdempsky): Rename this header to syscall_set.h.
+
+// Iterates over the entire system call range from 0..0xFFFFFFFFu. This
+// iterator is aware of how system calls look like and will skip quickly
+// over ranges that can't contain system calls. It iterates more slowly
+// whenever it reaches a range that is potentially problematic, returning
+// the last invalid value before a valid range of system calls, and the
+// first invalid value after a valid range of syscalls. It iterates over
+// individual values whenever it is in the normal range for system calls
+// (typically MIN_SYSCALL..MAX_SYSCALL).
+//
+// Example usage:
+//   for (uint32_t sysnum : SyscallSet::All()) {
+//     // Do something with sysnum.
+//   }
+class SANDBOX_EXPORT SyscallSet {
+ public:
+  class Iterator;
+
+  SyscallSet(const SyscallSet& ss) : set_(ss.set_) {}
+  ~SyscallSet() {}
+
+  Iterator begin() const;
+  Iterator end() const;
+
+  // All returns a SyscallSet that contains both valid and invalid
+  // system call numbers.
+  static SyscallSet All() { return SyscallSet(Set::ALL); }
+
+  // InvalidOnly returns a SyscallSet that contains only invalid
+  // system call numbers, but still omits numbers in the middle of a
+  // range of invalid system call numbers.
+  static SyscallSet InvalidOnly() { return SyscallSet(Set::INVALID_ONLY); }
+
+  // IsValid returns whether |num| specifies a valid system call
+  // number.
+  static bool IsValid(uint32_t num);
+
+ private:
+  enum class Set { ALL, INVALID_ONLY };
+
+  explicit SyscallSet(Set set) : set_(set) {}
+
+  Set set_;
+
+  friend bool operator==(const SyscallSet&, const SyscallSet&);
+  DISALLOW_ASSIGN(SyscallSet);
+};
+
+SANDBOX_EXPORT bool operator==(const SyscallSet& lhs, const SyscallSet& rhs);
+
+// Iterator provides C++ input iterator semantics for traversing a
+// SyscallSet.
+class SyscallSet::Iterator {
+ public:
+  Iterator(const Iterator& it)
+      : set_(it.set_), done_(it.done_), num_(it.num_) {}
+  ~Iterator() {}
+
+  uint32_t operator*() const;
+  Iterator& operator++();
+
+ private:
+  Iterator(Set set, bool done);
+
+  Set set_;
+  bool done_;
+  uint32_t num_;
+
+  friend SyscallSet;
+  friend bool operator==(const Iterator&, const Iterator&);
+  DISALLOW_ASSIGN(Iterator);
+};
+
+SANDBOX_EXPORT bool operator==(const SyscallSet::Iterator& lhs,
+                               const SyscallSet::Iterator& rhs);
+SANDBOX_EXPORT bool operator!=(const SyscallSet::Iterator& lhs,
+                               const SyscallSet::Iterator& rhs);
+
+}  // namespace sandbox
+
+#endif  // SANDBOX_LINUX_SECCOMP_BPF_SYSCALL_ITERATOR_H__