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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.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "ipc/ipc_message.h"
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include "base/atomic_sequence_num.h"
#include "base/containers/span.h"
#include "base/logging.h"
#include "base/pickle.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "ipc/ipc_message_attachment.h"
#include "ipc/ipc_message_attachment_set.h"
#if BUILDFLAG(IS_POSIX)
#include "base/file_descriptor_posix.h"
#include "ipc/ipc_platform_file_attachment_posix.h"
#endif
namespace {
base::AtomicSequenceNumber g_ref_num;
// Create a reference number for identifying IPC messages in traces. The return
// values has the reference number stored in the upper 24 bits, leaving the low
// 8 bits set to 0 for use as flags.
inline uint32_t GetRefNumUpper24() {
base::trace_event::TraceLog* trace_log =
base::trace_event::TraceLog::GetInstance();
uint32_t pid = trace_log ? trace_log->process_id() : 0;
uint32_t count = g_ref_num.GetNext();
// The 24 bit hash is composed of 14 bits of the count and 10 bits of the
// Process ID. With the current trace event buffer cap, the 14-bit count did
// not appear to wrap during a trace. Note that it is not a big deal if
// collisions occur, as this is only used for debugging and trace analysis.
return ((pid << 14) | (count & 0x3fff)) << 8;
}
} // namespace
namespace IPC {
//------------------------------------------------------------------------------
Message::~Message() = default;
Message::Message() : base::Pickle(sizeof(Header)) {
header()->routing = header()->type = 0;
header()->flags = GetRefNumUpper24();
#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
header()->num_fds = 0;
header()->pad = 0;
#endif
Init();
}
Message::Message(int32_t routing_id, uint32_t type, PriorityValue priority)
: base::Pickle(sizeof(Header)) {
header()->routing = routing_id;
header()->type = type;
DCHECK((priority & 0xffffff00) == 0);
header()->flags = priority | GetRefNumUpper24();
#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
header()->num_fds = 0;
header()->pad = 0;
#endif
Init();
}
Message::Message(const char* data, size_t data_len)
: base::Pickle(base::Pickle::kUnownedData,
base::as_bytes(base::span(data, data_len))) {
Init();
}
Message::Message(const Message& other) : base::Pickle(other) {
Init();
attachment_set_ = other.attachment_set_;
}
void Message::Init() {
dispatch_error_ = false;
#if BUILDFLAG(IPC_MESSAGE_LOG_ENABLED)
received_time_ = 0;
dont_log_ = false;
log_data_ = nullptr;
#endif
}
Message& Message::operator=(const Message& other) {
*static_cast<base::Pickle*>(this) = other;
attachment_set_ = other.attachment_set_;
return *this;
}
void Message::SetHeaderValues(int32_t routing, uint32_t type, uint32_t flags) {
// This should only be called when the message is already empty.
DCHECK(payload_size() == 0);
header()->routing = routing;
header()->type = type;
header()->flags = flags;
}
void Message::EnsureMessageAttachmentSet() {
if (!attachment_set_.get())
attachment_set_ = new MessageAttachmentSet;
}
#if BUILDFLAG(IPC_MESSAGE_LOG_ENABLED)
void Message::set_sent_time(int64_t time) {
DCHECK((header()->flags & HAS_SENT_TIME_BIT) == 0);
header()->flags |= HAS_SENT_TIME_BIT;
WriteInt64(time);
}
int64_t Message::sent_time() const {
if ((header()->flags & HAS_SENT_TIME_BIT) == 0)
return 0;
const char* data = end_of_payload();
data -= sizeof(int64_t);
return *(reinterpret_cast<const int64_t*>(data));
}
void Message::set_received_time(int64_t time) const {
received_time_ = time;
}
#endif // BUILDFLAG(IPC_MESSAGE_LOG_ENABLED)
Message::NextMessageInfo::NextMessageInfo()
: message_size(0), message_found(false), pickle_end(nullptr),
message_end(nullptr) {}
Message::NextMessageInfo::~NextMessageInfo() = default;
// static
void Message::FindNext(const char* range_start,
const char* range_end,
NextMessageInfo* info) {
DCHECK(info);
info->message_found = false;
info->message_size = 0;
size_t pickle_size = 0;
if (!base::Pickle::PeekNext(sizeof(Header),
range_start, range_end, &pickle_size))
return;
bool have_entire_pickle =
static_cast<size_t>(range_end - range_start) >= pickle_size;
info->message_size = pickle_size;
if (!have_entire_pickle)
return;
const char* pickle_end = range_start + pickle_size;
info->message_end = pickle_end;
info->pickle_end = pickle_end;
info->message_found = true;
}
bool Message::WriteAttachment(
scoped_refptr<base::Pickle::Attachment> attachment) {
size_t index;
bool success = attachment_set()->AddAttachment(
base::WrapRefCounted(static_cast<MessageAttachment*>(attachment.get())),
&index);
DCHECK(success);
// Write the index of the descriptor so that we don't have to
// keep the current descriptor as extra decoding state when deserialising.
WriteInt(static_cast<int>(index));
return success;
}
bool Message::ReadAttachment(
base::PickleIterator* iter,
scoped_refptr<base::Pickle::Attachment>* attachment) const {
int index;
if (!iter->ReadInt(&index))
return false;
MessageAttachmentSet* attachment_set = attachment_set_.get();
if (!attachment_set)
return false;
*attachment = attachment_set->GetAttachmentAt(index);
return nullptr != attachment->get();
}
bool Message::HasAttachments() const {
return attachment_set_.get() && !attachment_set_->empty();
}
} // namespace IPC
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