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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ipc/ipc_channel.h"
#include <stddef.h>
#include <stdint.h>
#include <limits>
#include "base/atomic_sequence_num.h"
#include "base/rand_util.h"
#include "base/strings/stringprintf.h"
#include "build/build_config.h"
namespace {
// Global atomic used to guarantee channel IDs are unique.
base::AtomicSequenceNumber g_last_id;
} // namespace
namespace IPC {
// static
constexpr size_t Channel::kMaximumMessageSize;
// static
std::string Channel::GenerateUniqueRandomChannelID() {
// Note: the string must start with the current process id, this is how
// some child processes determine the pid of the parent.
//
// This is composed of a unique incremental identifier, the process ID of
// the creator, an identifier for the child instance, and a strong random
// component. The strong random component prevents other processes from
// hijacking or squatting on predictable channel names.
int process_id = base::GetCurrentProcId();
return base::StringPrintf("%d.%u.%d",
process_id,
g_last_id.GetNext(),
base::RandInt(0, std::numeric_limits<int32_t>::max()));
}
} // namespace IPC
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