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 #include "ipc/ipc_channel.h" 6 7 #include <limits> 8 9 #include "base/atomic_sequence_num.h" 10 #include "base/rand_util.h" 11 #include "base/strings/stringprintf.h" 12 13 #if !defined(OS_NACL) 14 namespace { 15 16 // Global atomic used to guarantee channel IDs are unique. 17 base::StaticAtomicSequenceNumber g_last_id; 18 19 } // namespace 20 #endif 21 22 namespace IPC { 23 24 // static GenerateUniqueRandomChannelID()25std::string Channel::GenerateUniqueRandomChannelID() { 26 // Note: the string must start with the current process id, this is how 27 // some child processes determine the pid of the parent. 28 // 29 // This is composed of a unique incremental identifier, the process ID of 30 // the creator, an identifier for the child instance, and a strong random 31 // component. The strong random component prevents other processes from 32 // hijacking or squatting on predictable channel names. 33 34 int process_id = base::GetCurrentProcId(); 35 return base::StringPrintf("%d.%u.%d", 36 process_id, 37 g_last_id.GetNext(), 38 base::RandInt(0, std::numeric_limits<int32>::max())); 39 } 40 41 } // namespace IPC 42 43