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// Copyright 2014 The Crashpad Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "minidump/minidump_file_writer.h"
#include <utility>
#include "base/logging.h"
#include "minidump/minidump_crashpad_info_writer.h"
#include "minidump/minidump_exception_writer.h"
#include "minidump/minidump_handle_writer.h"
#include "minidump/minidump_memory_info_writer.h"
#include "minidump/minidump_memory_writer.h"
#include "minidump/minidump_misc_info_writer.h"
#include "minidump/minidump_module_writer.h"
#include "minidump/minidump_system_info_writer.h"
#include "minidump/minidump_thread_id_map.h"
#include "minidump/minidump_thread_writer.h"
#include "minidump/minidump_unloaded_module_writer.h"
#include "minidump/minidump_user_extension_stream_data_source.h"
#include "minidump/minidump_user_stream_writer.h"
#include "minidump/minidump_writer_util.h"
#include "snapshot/exception_snapshot.h"
#include "snapshot/module_snapshot.h"
#include "snapshot/process_snapshot.h"
#include "util/file/file_writer.h"
#include "util/numeric/safe_assignment.h"
namespace crashpad {
MinidumpFileWriter::MinidumpFileWriter()
: MinidumpWritable(), header_(), streams_(), stream_types_() {
// Don’t set the signature field right away. Leave it set to 0, so that a
// partially-written minidump file isn’t confused for a complete and valid
// one. The header will be rewritten in WriteToFile().
header_.Signature = 0;
header_.Version = MINIDUMP_VERSION;
header_.CheckSum = 0;
header_.Flags = MiniDumpNormal;
}
MinidumpFileWriter::~MinidumpFileWriter() {
}
void MinidumpFileWriter::InitializeFromSnapshot(
const ProcessSnapshot* process_snapshot) {
DCHECK_EQ(state(), kStateMutable);
DCHECK_EQ(header_.Signature, 0u);
DCHECK_EQ(header_.TimeDateStamp, 0u);
DCHECK_EQ(static_cast<MINIDUMP_TYPE>(header_.Flags), MiniDumpNormal);
DCHECK(streams_.empty());
// This time is truncated to an integer number of seconds, not rounded, for
// compatibility with the truncation of process_snapshot->ProcessStartTime()
// done by MinidumpMiscInfoWriter::InitializeFromSnapshot(). Handling both
// timestamps in the same way allows the highest-fidelity computation of
// process uptime as the difference between the two values.
timeval snapshot_time;
process_snapshot->SnapshotTime(&snapshot_time);
SetTimestamp(snapshot_time.tv_sec);
const SystemSnapshot* system_snapshot = process_snapshot->System();
auto system_info = std::make_unique<MinidumpSystemInfoWriter>();
system_info->InitializeFromSnapshot(system_snapshot);
bool add_stream_result = AddStream(std::move(system_info));
DCHECK(add_stream_result);
auto misc_info = std::make_unique<MinidumpMiscInfoWriter>();
misc_info->InitializeFromSnapshot(process_snapshot);
add_stream_result = AddStream(std::move(misc_info));
DCHECK(add_stream_result);
auto memory_list = std::make_unique<MinidumpMemoryListWriter>();
auto thread_list = std::make_unique<MinidumpThreadListWriter>();
thread_list->SetMemoryListWriter(memory_list.get());
MinidumpThreadIDMap thread_id_map;
thread_list->InitializeFromSnapshot(process_snapshot->Threads(),
&thread_id_map);
add_stream_result = AddStream(std::move(thread_list));
DCHECK(add_stream_result);
const ExceptionSnapshot* exception_snapshot = process_snapshot->Exception();
if (exception_snapshot) {
auto exception = std::make_unique<MinidumpExceptionWriter>();
exception->InitializeFromSnapshot(exception_snapshot, thread_id_map);
add_stream_result = AddStream(std::move(exception));
DCHECK(add_stream_result);
}
auto module_list = std::make_unique<MinidumpModuleListWriter>();
module_list->InitializeFromSnapshot(process_snapshot->Modules());
add_stream_result = AddStream(std::move(module_list));
DCHECK(add_stream_result);
auto unloaded_modules = process_snapshot->UnloadedModules();
if (!unloaded_modules.empty()) {
auto unloaded_module_list =
std::make_unique<MinidumpUnloadedModuleListWriter>();
unloaded_module_list->InitializeFromSnapshot(unloaded_modules);
add_stream_result = AddStream(std::move(unloaded_module_list));
DCHECK(add_stream_result);
}
auto crashpad_info = std::make_unique<MinidumpCrashpadInfoWriter>();
crashpad_info->InitializeFromSnapshot(process_snapshot);
// Since the MinidumpCrashpadInfo stream is an extension, it’s safe to not add
// it to the minidump file if it wouldn’t carry any useful information.
if (crashpad_info->IsUseful()) {
add_stream_result = AddStream(std::move(crashpad_info));
DCHECK(add_stream_result);
}
std::vector<const MemoryMapRegionSnapshot*> memory_map_snapshot =
process_snapshot->MemoryMap();
if (!memory_map_snapshot.empty()) {
auto memory_info_list = std::make_unique<MinidumpMemoryInfoListWriter>();
memory_info_list->InitializeFromSnapshot(memory_map_snapshot);
add_stream_result = AddStream(std::move(memory_info_list));
DCHECK(add_stream_result);
}
std::vector<HandleSnapshot> handles_snapshot = process_snapshot->Handles();
if (!handles_snapshot.empty()) {
auto handle_data_writer = std::make_unique<MinidumpHandleDataWriter>();
handle_data_writer->InitializeFromSnapshot(handles_snapshot);
add_stream_result = AddStream(std::move(handle_data_writer));
DCHECK(add_stream_result);
}
memory_list->AddFromSnapshot(process_snapshot->ExtraMemory());
if (exception_snapshot) {
memory_list->AddFromSnapshot(exception_snapshot->ExtraMemory());
}
// These user streams must be added last. Otherwise, a user stream with the
// same type as a well-known stream could preempt the well-known stream. As it
// stands now, earlier-discovered user streams can still preempt
// later-discovered ones. The well-known memory list stream is added after
// these user streams, but only with a check here to avoid adding a user
// stream that would preempt the memory list stream.
for (const auto& module : process_snapshot->Modules()) {
for (const UserMinidumpStream* stream : module->CustomMinidumpStreams()) {
if (stream->stream_type() == kMinidumpStreamTypeMemoryList) {
LOG(WARNING) << "discarding duplicate stream of type "
<< stream->stream_type();
continue;
}
auto user_stream = std::make_unique<MinidumpUserStreamWriter>();
user_stream->InitializeFromSnapshot(stream);
AddStream(std::move(user_stream));
}
}
// The memory list stream should be added last. This keeps the “extra memory”
// at the end so that if the minidump file is truncated, other, more critical
// data is more likely to be preserved. Note that non-“extra” memory regions
// will not have to ride at the end of the file. Thread stack memory, for
// example, exists as a children of threads, and appears alongside them in the
// file, despite also being mentioned by the memory list stream.
add_stream_result = AddStream(std::move(memory_list));
DCHECK(add_stream_result);
}
void MinidumpFileWriter::SetTimestamp(time_t timestamp) {
DCHECK_EQ(state(), kStateMutable);
internal::MinidumpWriterUtil::AssignTimeT(&header_.TimeDateStamp, timestamp);
}
bool MinidumpFileWriter::AddStream(
std::unique_ptr<internal::MinidumpStreamWriter> stream) {
DCHECK_EQ(state(), kStateMutable);
MinidumpStreamType stream_type = stream->StreamType();
auto rv = stream_types_.insert(stream_type);
if (!rv.second) {
LOG(WARNING) << "discarding duplicate stream of type " << stream_type;
return false;
}
streams_.push_back(std::move(stream));
DCHECK_EQ(streams_.size(), stream_types_.size());
return true;
}
bool MinidumpFileWriter::AddUserExtensionStream(
std::unique_ptr<MinidumpUserExtensionStreamDataSource>
user_extension_stream_data) {
DCHECK_EQ(state(), kStateMutable);
auto user_stream = std::make_unique<MinidumpUserStreamWriter>();
user_stream->InitializeFromUserExtensionStream(
std::move(user_extension_stream_data));
return AddStream(std::move(user_stream));
}
bool MinidumpFileWriter::WriteEverything(FileWriterInterface* file_writer) {
DCHECK_EQ(state(), kStateMutable);
FileOffset start_offset = file_writer->Seek(0, SEEK_CUR);
if (start_offset < 0) {
return false;
}
if (!MinidumpWritable::WriteEverything(file_writer)) {
return false;
}
FileOffset end_offset = file_writer->Seek(0, SEEK_CUR);
if (end_offset < 0) {
return false;
}
// Now that the entire minidump file has been completely written, go back to
// the beginning and rewrite the header with the correct signature to identify
// it as a valid minidump file.
header_.Signature = MINIDUMP_SIGNATURE;
if (file_writer->Seek(start_offset, SEEK_SET) < 0) {
return false;
}
if (!file_writer->Write(&header_, sizeof(header_))) {
return false;
}
// Seek back to the end of the file, in case some non-minidump content will be
// written to the file after the minidump content.
return file_writer->Seek(end_offset, SEEK_SET) >= 0;
}
bool MinidumpFileWriter::Freeze() {
DCHECK_EQ(state(), kStateMutable);
if (!MinidumpWritable::Freeze()) {
return false;
}
size_t stream_count = streams_.size();
CHECK_EQ(stream_count, stream_types_.size());
if (!AssignIfInRange(&header_.NumberOfStreams, stream_count)) {
LOG(ERROR) << "stream_count " << stream_count << " out of range";
return false;
}
return true;
}
size_t MinidumpFileWriter::SizeOfObject() {
DCHECK_GE(state(), kStateFrozen);
DCHECK_EQ(streams_.size(), stream_types_.size());
return sizeof(header_) + streams_.size() * sizeof(MINIDUMP_DIRECTORY);
}
std::vector<internal::MinidumpWritable*> MinidumpFileWriter::Children() {
DCHECK_GE(state(), kStateFrozen);
DCHECK_EQ(streams_.size(), stream_types_.size());
std::vector<MinidumpWritable*> children;
for (const auto& stream : streams_) {
children.push_back(stream.get());
}
return children;
}
bool MinidumpFileWriter::WillWriteAtOffsetImpl(FileOffset offset) {
DCHECK_EQ(state(), kStateFrozen);
DCHECK_EQ(offset, 0);
DCHECK_EQ(streams_.size(), stream_types_.size());
auto directory_offset = streams_.empty() ? 0 : offset + sizeof(header_);
if (!AssignIfInRange(&header_.StreamDirectoryRva, directory_offset)) {
LOG(ERROR) << "offset " << directory_offset << " out of range";
return false;
}
return MinidumpWritable::WillWriteAtOffsetImpl(offset);
}
bool MinidumpFileWriter::WriteObject(FileWriterInterface* file_writer) {
DCHECK_EQ(state(), kStateWritable);
DCHECK_EQ(streams_.size(), stream_types_.size());
WritableIoVec iov;
iov.iov_base = &header_;
iov.iov_len = sizeof(header_);
std::vector<WritableIoVec> iovecs(1, iov);
for (const auto& stream : streams_) {
iov.iov_base = stream->DirectoryListEntry();
iov.iov_len = sizeof(MINIDUMP_DIRECTORY);
iovecs.push_back(iov);
}
return file_writer->WriteIoVec(&iovecs);
}
} // namespace crashpad