1 //===-- ProcessMinidump.cpp -------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // Project includes
11 #include "ProcessMinidump.h"
12 #include "ThreadMinidump.h"
13 
14 // Other libraries and framework includes
15 #include "lldb/Core/Module.h"
16 #include "lldb/Core/ModuleSpec.h"
17 #include "lldb/Core/PluginManager.h"
18 #include "lldb/Core/Section.h"
19 #include "lldb/Core/State.h"
20 #include "lldb/Target/DynamicLoader.h"
21 #include "lldb/Target/MemoryRegionInfo.h"
22 #include "lldb/Target/SectionLoadList.h"
23 #include "lldb/Target/Target.h"
24 #include "lldb/Target/UnixSignals.h"
25 #include "lldb/Utility/DataBufferLLVM.h"
26 #include "lldb/Utility/LLDBAssert.h"
27 #include "lldb/Utility/Log.h"
28 
29 #include "llvm/Support/MemoryBuffer.h"
30 #include "llvm/Support/Threading.h"
31 
32 // C includes
33 // C++ includes
34 
35 using namespace lldb;
36 using namespace lldb_private;
37 using namespace minidump;
38 
39 //------------------------------------------------------------------
40 /// A placeholder module used for minidumps, where the original
41 /// object files may not be available (so we can't parse the object
42 /// files to extract the set of sections/segments)
43 ///
44 /// This placeholder module has a single synthetic section (.module_image)
45 /// which represents the module memory range covering the whole module.
46 //------------------------------------------------------------------
47 class PlaceholderModule : public Module {
48 public:
49   PlaceholderModule(const ModuleSpec &module_spec) :
50     Module(module_spec.GetFileSpec(), module_spec.GetArchitecture()) {
51     if (module_spec.GetUUID().IsValid())
52       SetUUID(module_spec.GetUUID());
53   }
54 
55   // Creates a synthetic module section covering the whole module image (and
56   // sets the section load address as well)
57   void CreateImageSection(const MinidumpModule *module, Target& target) {
58     const ConstString section_name(".module_image");
59     lldb::SectionSP section_sp(new Section(
60         shared_from_this(),     // Module to which this section belongs.
61         nullptr,                // ObjectFile
62         0,                      // Section ID.
63         section_name,           // Section name.
64         eSectionTypeContainer,  // Section type.
65         module->base_of_image,  // VM address.
66         module->size_of_image,  // VM size in bytes of this section.
67         0,                      // Offset of this section in the file.
68         module->size_of_image,  // Size of the section as found in the file.
69         12,                     // Alignment of the section (log2)
70         0,                      // Flags for this section.
71         1));                    // Number of host bytes per target byte
72     section_sp->SetPermissions(ePermissionsExecutable | ePermissionsReadable);
73     GetSectionList()->AddSection(section_sp);
74     target.GetSectionLoadList().SetSectionLoadAddress(
75         section_sp, module->base_of_image);
76   }
77 
78   ObjectFile *GetObjectFile() override { return nullptr; }
79 
80   SectionList *GetSectionList() override {
81     return Module::GetUnifiedSectionList();
82   }
83 };
84 
85 ConstString ProcessMinidump::GetPluginNameStatic() {
86   static ConstString g_name("minidump");
87   return g_name;
88 }
89 
90 const char *ProcessMinidump::GetPluginDescriptionStatic() {
91   return "Minidump plug-in.";
92 }
93 
94 lldb::ProcessSP ProcessMinidump::CreateInstance(lldb::TargetSP target_sp,
95                                                 lldb::ListenerSP listener_sp,
96                                                 const FileSpec *crash_file) {
97   if (!crash_file)
98     return nullptr;
99 
100   lldb::ProcessSP process_sp;
101   // Read enough data for the Minidump header
102   constexpr size_t header_size = sizeof(MinidumpHeader);
103   auto DataPtr =
104       DataBufferLLVM::CreateSliceFromPath(crash_file->GetPath(), header_size, 0);
105   if (!DataPtr)
106     return nullptr;
107 
108   assert(DataPtr->GetByteSize() == header_size);
109 
110   // first, only try to parse the header, beacuse we need to be fast
111   llvm::ArrayRef<uint8_t> HeaderBytes = DataPtr->GetData();
112   const MinidumpHeader *header = MinidumpHeader::Parse(HeaderBytes);
113   if (header == nullptr)
114     return nullptr;
115 
116   auto AllData = DataBufferLLVM::CreateSliceFromPath(crash_file->GetPath(), -1, 0);
117   if (!AllData)
118     return nullptr;
119 
120   auto minidump_parser = MinidumpParser::Create(AllData);
121   // check if the parser object is valid
122   if (!minidump_parser)
123     return nullptr;
124 
125   return std::make_shared<ProcessMinidump>(target_sp, listener_sp, *crash_file,
126                                            minidump_parser.getValue());
127 }
128 
129 bool ProcessMinidump::CanDebug(lldb::TargetSP target_sp,
130                                bool plugin_specified_by_name) {
131   return true;
132 }
133 
134 ProcessMinidump::ProcessMinidump(lldb::TargetSP target_sp,
135                                  lldb::ListenerSP listener_sp,
136                                  const FileSpec &core_file,
137                                  MinidumpParser minidump_parser)
138     : Process(target_sp, listener_sp), m_minidump_parser(minidump_parser),
139       m_core_file(core_file), m_is_wow64(false) {}
140 
141 ProcessMinidump::~ProcessMinidump() {
142   Clear();
143   // We need to call finalize on the process before destroying ourselves to
144   // make sure all of the broadcaster cleanup goes as planned. If we destruct
145   // this class, then Process::~Process() might have problems trying to fully
146   // destroy the broadcaster.
147   Finalize();
148 }
149 
150 void ProcessMinidump::Initialize() {
151   static llvm::once_flag g_once_flag;
152 
153   llvm::call_once(g_once_flag, []() {
154     PluginManager::RegisterPlugin(GetPluginNameStatic(),
155                                   GetPluginDescriptionStatic(),
156                                   ProcessMinidump::CreateInstance);
157   });
158 }
159 
160 void ProcessMinidump::Terminate() {
161   PluginManager::UnregisterPlugin(ProcessMinidump::CreateInstance);
162 }
163 
164 Status ProcessMinidump::DoLoadCore() {
165   Status error;
166 
167   m_thread_list = m_minidump_parser.GetThreads();
168   m_active_exception = m_minidump_parser.GetExceptionStream();
169   ReadModuleList();
170   GetTarget().SetArchitecture(GetArchitecture());
171 
172   llvm::Optional<lldb::pid_t> pid = m_minidump_parser.GetPid();
173   if (!pid) {
174     error.SetErrorString("failed to parse PID");
175     return error;
176   }
177   SetID(pid.getValue());
178 
179   return error;
180 }
181 
182 DynamicLoader *ProcessMinidump::GetDynamicLoader() {
183   if (m_dyld_ap.get() == nullptr)
184     m_dyld_ap.reset(DynamicLoader::FindPlugin(this, nullptr));
185   return m_dyld_ap.get();
186 }
187 
188 ConstString ProcessMinidump::GetPluginName() { return GetPluginNameStatic(); }
189 
190 uint32_t ProcessMinidump::GetPluginVersion() { return 1; }
191 
192 Status ProcessMinidump::DoDestroy() { return Status(); }
193 
194 void ProcessMinidump::RefreshStateAfterStop() {
195   if (!m_active_exception)
196     return;
197 
198   if (m_active_exception->exception_record.exception_code ==
199       MinidumpException::DumpRequested) {
200     return;
201   }
202 
203   lldb::StopInfoSP stop_info;
204   lldb::ThreadSP stop_thread;
205 
206   Process::m_thread_list.SetSelectedThreadByID(m_active_exception->thread_id);
207   stop_thread = Process::m_thread_list.GetSelectedThread();
208   ArchSpec arch = GetArchitecture();
209 
210   if (arch.GetTriple().getOS() == llvm::Triple::Linux) {
211     stop_info = StopInfo::CreateStopReasonWithSignal(
212         *stop_thread, m_active_exception->exception_record.exception_code);
213   } else {
214     std::string desc;
215     llvm::raw_string_ostream desc_stream(desc);
216     desc_stream << "Exception "
217                 << llvm::format_hex(
218                        m_active_exception->exception_record.exception_code, 8)
219                 << " encountered at address "
220                 << llvm::format_hex(
221                        m_active_exception->exception_record.exception_address,
222                        8);
223     stop_info = StopInfo::CreateStopReasonWithException(
224         *stop_thread, desc_stream.str().c_str());
225   }
226 
227   stop_thread->SetStopInfo(stop_info);
228 }
229 
230 bool ProcessMinidump::IsAlive() { return true; }
231 
232 bool ProcessMinidump::WarnBeforeDetach() const { return false; }
233 
234 size_t ProcessMinidump::ReadMemory(lldb::addr_t addr, void *buf, size_t size,
235                                    Status &error) {
236   // Don't allow the caching that lldb_private::Process::ReadMemory does since
237   // we have it all cached in our dump file anyway.
238   return DoReadMemory(addr, buf, size, error);
239 }
240 
241 size_t ProcessMinidump::DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
242                                      Status &error) {
243 
244   llvm::ArrayRef<uint8_t> mem = m_minidump_parser.GetMemory(addr, size);
245   if (mem.empty()) {
246     error.SetErrorString("could not parse memory info");
247     return 0;
248   }
249 
250   std::memcpy(buf, mem.data(), mem.size());
251   return mem.size();
252 }
253 
254 ArchSpec ProcessMinidump::GetArchitecture() {
255   if (!m_is_wow64) {
256     return m_minidump_parser.GetArchitecture();
257   }
258 
259   llvm::Triple triple;
260   triple.setVendor(llvm::Triple::VendorType::UnknownVendor);
261   triple.setArch(llvm::Triple::ArchType::x86);
262   triple.setOS(llvm::Triple::OSType::Win32);
263   return ArchSpec(triple);
264 }
265 
266 Status ProcessMinidump::GetMemoryRegionInfo(lldb::addr_t load_addr,
267                                             MemoryRegionInfo &range_info) {
268   Status error;
269   auto info = m_minidump_parser.GetMemoryRegionInfo(load_addr);
270   if (!info) {
271     error.SetErrorString("No valid MemoryRegionInfo found!");
272     return error;
273   }
274   range_info = info.getValue();
275   return error;
276 }
277 
278 void ProcessMinidump::Clear() { Process::m_thread_list.Clear(); }
279 
280 bool ProcessMinidump::UpdateThreadList(ThreadList &old_thread_list,
281                                        ThreadList &new_thread_list) {
282   uint32_t num_threads = 0;
283   if (m_thread_list.size() > 0)
284     num_threads = m_thread_list.size();
285 
286   for (lldb::tid_t tid = 0; tid < num_threads; ++tid) {
287     llvm::ArrayRef<uint8_t> context;
288     if (!m_is_wow64)
289       context = m_minidump_parser.GetThreadContext(m_thread_list[tid]);
290     else
291       context = m_minidump_parser.GetThreadContextWow64(m_thread_list[tid]);
292 
293     lldb::ThreadSP thread_sp(
294         new ThreadMinidump(*this, m_thread_list[tid], context));
295     new_thread_list.AddThread(thread_sp);
296   }
297   return new_thread_list.GetSize(false) > 0;
298 }
299 
300 void ProcessMinidump::ReadModuleList() {
301   std::vector<const MinidumpModule *> filtered_modules =
302       m_minidump_parser.GetFilteredModuleList();
303 
304   for (auto module : filtered_modules) {
305     llvm::Optional<std::string> name =
306         m_minidump_parser.GetMinidumpString(module->module_name_rva);
307 
308     if (!name)
309       continue;
310 
311     Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_MODULES));
312     if (log) {
313       log->Printf("ProcessMinidump::%s found module: name: %s %#010" PRIx64
314                   "-%#010" PRIx64 " size: %" PRIu32,
315                   __FUNCTION__, name.getValue().c_str(),
316                   uint64_t(module->base_of_image),
317                   module->base_of_image + module->size_of_image,
318                   uint32_t(module->size_of_image));
319     }
320 
321     // check if the process is wow64 - a 32 bit windows process running on a
322     // 64 bit windows
323     if (llvm::StringRef(name.getValue()).endswith_lower("wow64.dll")) {
324       m_is_wow64 = true;
325     }
326 
327     const auto uuid = m_minidump_parser.GetModuleUUID(module);
328     const auto file_spec =
329         FileSpec(name.getValue(), true, GetArchitecture().GetTriple());
330     ModuleSpec module_spec(file_spec, uuid);
331     Status error;
332     lldb::ModuleSP module_sp = GetTarget().GetSharedModule(module_spec, &error);
333     if (!module_sp || error.Fail()) {
334       // We failed to locate a matching local object file. Fortunately, the
335       // minidump format encodes enough information about each module's memory
336       // range to allow us to create placeholder modules.
337       //
338       // This enables most LLDB functionality involving address-to-module
339       // translations (ex. identifing the module for a stack frame PC) and
340       // modules/sections commands (ex. target modules list, ...)
341       auto placeholder_module =
342           std::make_shared<PlaceholderModule>(module_spec);
343       placeholder_module->CreateImageSection(module, GetTarget());
344       module_sp = placeholder_module;
345       GetTarget().GetImages().Append(module_sp);
346     }
347 
348     if (log) {
349       log->Printf("ProcessMinidump::%s load module: name: %s", __FUNCTION__,
350                   name.getValue().c_str());
351     }
352 
353     bool load_addr_changed = false;
354     module_sp->SetLoadAddress(GetTarget(), module->base_of_image, false,
355                               load_addr_changed);
356   }
357 }
358 
359 bool ProcessMinidump::GetProcessInfo(ProcessInstanceInfo &info) {
360   info.Clear();
361   info.SetProcessID(GetID());
362   info.SetArchitecture(GetArchitecture());
363   lldb::ModuleSP module_sp = GetTarget().GetExecutableModule();
364   if (module_sp) {
365     const bool add_exe_file_as_first_arg = false;
366     info.SetExecutableFile(GetTarget().GetExecutableModule()->GetFileSpec(),
367                            add_exe_file_as_first_arg);
368   }
369   return true;
370 }
371