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/Target/JITLoaderList.h"
20 #include "lldb/Target/MemoryRegionInfo.h"
21 #include "lldb/Target/SectionLoadList.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Target/UnixSignals.h"
24 #include "lldb/Utility/LLDBAssert.h"
25 #include "lldb/Utility/Log.h"
26 #include "lldb/Utility/State.h"
27 
28 #include "llvm/Support/MemoryBuffer.h"
29 #include "llvm/Support/Threading.h"
30 
31 #include "Plugins/Process/Utility/StopInfoMachException.h"
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 = FileSystem::Instance().CreateDataBuffer(crash_file->GetPath(),
104                                                          header_size, 0);
105   if (!DataPtr)
106     return nullptr;
107 
108   lldbassert(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 =
117       FileSystem::Instance().CreateDataBuffer(crash_file->GetPath(), -1, 0);
118   if (!AllData)
119     return nullptr;
120 
121   auto minidump_parser = MinidumpParser::Create(AllData);
122   // check if the parser object is valid
123   if (!minidump_parser)
124     return nullptr;
125 
126   return std::make_shared<ProcessMinidump>(target_sp, listener_sp, *crash_file,
127                                            minidump_parser.getValue());
128 }
129 
130 bool ProcessMinidump::CanDebug(lldb::TargetSP target_sp,
131                                bool plugin_specified_by_name) {
132   return true;
133 }
134 
135 ProcessMinidump::ProcessMinidump(lldb::TargetSP target_sp,
136                                  lldb::ListenerSP listener_sp,
137                                  const FileSpec &core_file,
138                                  MinidumpParser minidump_parser)
139     : Process(target_sp, listener_sp), m_minidump_parser(minidump_parser),
140       m_core_file(core_file), m_is_wow64(false) {}
141 
142 ProcessMinidump::~ProcessMinidump() {
143   Clear();
144   // We need to call finalize on the process before destroying ourselves to
145   // make sure all of the broadcaster cleanup goes as planned. If we destruct
146   // this class, then Process::~Process() might have problems trying to fully
147   // destroy the broadcaster.
148   Finalize();
149 }
150 
151 void ProcessMinidump::Initialize() {
152   static llvm::once_flag g_once_flag;
153 
154   llvm::call_once(g_once_flag, []() {
155     PluginManager::RegisterPlugin(GetPluginNameStatic(),
156                                   GetPluginDescriptionStatic(),
157                                   ProcessMinidump::CreateInstance);
158   });
159 }
160 
161 void ProcessMinidump::Terminate() {
162   PluginManager::UnregisterPlugin(ProcessMinidump::CreateInstance);
163 }
164 
165 Status ProcessMinidump::DoLoadCore() {
166   Status error;
167 
168   // Minidump parser initialization & consistency checks
169   error = m_minidump_parser.Initialize();
170   if (error.Fail())
171     return error;
172 
173   // Do we support the minidump's architecture?
174   ArchSpec arch = GetArchitecture();
175   switch (arch.GetMachine()) {
176   case llvm::Triple::x86:
177   case llvm::Triple::x86_64:
178   case llvm::Triple::arm:
179   case llvm::Triple::aarch64:
180     // Any supported architectures must be listed here and also supported in
181     // ThreadMinidump::CreateRegisterContextForFrame().
182     break;
183   default:
184     error.SetErrorStringWithFormat("unsupported minidump architecture: %s",
185                                    arch.GetArchitectureName());
186     return error;
187   }
188   GetTarget().SetArchitecture(arch, true /*set_platform*/);
189 
190   m_thread_list = m_minidump_parser.GetThreads();
191   m_active_exception = m_minidump_parser.GetExceptionStream();
192   ReadModuleList();
193 
194   llvm::Optional<lldb::pid_t> pid = m_minidump_parser.GetPid();
195   if (!pid) {
196     error.SetErrorString("failed to parse PID");
197     return error;
198   }
199   SetID(pid.getValue());
200 
201   return error;
202 }
203 
204 ConstString ProcessMinidump::GetPluginName() { return GetPluginNameStatic(); }
205 
206 uint32_t ProcessMinidump::GetPluginVersion() { return 1; }
207 
208 Status ProcessMinidump::DoDestroy() { return Status(); }
209 
210 void ProcessMinidump::RefreshStateAfterStop() {
211   if (!m_active_exception)
212     return;
213 
214   if (m_active_exception->exception_record.exception_code ==
215       MinidumpException::DumpRequested) {
216     return;
217   }
218 
219   lldb::StopInfoSP stop_info;
220   lldb::ThreadSP stop_thread;
221 
222   Process::m_thread_list.SetSelectedThreadByID(m_active_exception->thread_id);
223   stop_thread = Process::m_thread_list.GetSelectedThread();
224   ArchSpec arch = GetArchitecture();
225 
226   if (arch.GetTriple().getOS() == llvm::Triple::Linux) {
227     stop_info = StopInfo::CreateStopReasonWithSignal(
228         *stop_thread, m_active_exception->exception_record.exception_code);
229   } else if (arch.GetTriple().getVendor() == llvm::Triple::Apple) {
230     stop_info = StopInfoMachException::CreateStopReasonWithMachException(
231         *stop_thread, m_active_exception->exception_record.exception_code, 2,
232         m_active_exception->exception_record.exception_flags,
233         m_active_exception->exception_record.exception_address, 0);
234   } else {
235     std::string desc;
236     llvm::raw_string_ostream desc_stream(desc);
237     desc_stream << "Exception "
238                 << llvm::format_hex(
239                        m_active_exception->exception_record.exception_code, 8)
240                 << " encountered at address "
241                 << llvm::format_hex(
242                        m_active_exception->exception_record.exception_address,
243                        8);
244     stop_info = StopInfo::CreateStopReasonWithException(
245         *stop_thread, desc_stream.str().c_str());
246   }
247 
248   stop_thread->SetStopInfo(stop_info);
249 }
250 
251 bool ProcessMinidump::IsAlive() { return true; }
252 
253 bool ProcessMinidump::WarnBeforeDetach() const { return false; }
254 
255 size_t ProcessMinidump::ReadMemory(lldb::addr_t addr, void *buf, size_t size,
256                                    Status &error) {
257   // Don't allow the caching that lldb_private::Process::ReadMemory does since
258   // we have it all cached in our dump file anyway.
259   return DoReadMemory(addr, buf, size, error);
260 }
261 
262 size_t ProcessMinidump::DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
263                                      Status &error) {
264 
265   llvm::ArrayRef<uint8_t> mem = m_minidump_parser.GetMemory(addr, size);
266   if (mem.empty()) {
267     error.SetErrorString("could not parse memory info");
268     return 0;
269   }
270 
271   std::memcpy(buf, mem.data(), mem.size());
272   return mem.size();
273 }
274 
275 ArchSpec ProcessMinidump::GetArchitecture() {
276   if (!m_is_wow64) {
277     return m_minidump_parser.GetArchitecture();
278   }
279 
280   llvm::Triple triple;
281   triple.setVendor(llvm::Triple::VendorType::UnknownVendor);
282   triple.setArch(llvm::Triple::ArchType::x86);
283   triple.setOS(llvm::Triple::OSType::Win32);
284   return ArchSpec(triple);
285 }
286 
287 Status ProcessMinidump::GetMemoryRegionInfo(lldb::addr_t load_addr,
288                                             MemoryRegionInfo &range_info) {
289   Status error;
290   auto info = m_minidump_parser.GetMemoryRegionInfo(load_addr);
291   if (!info) {
292     error.SetErrorString("No valid MemoryRegionInfo found!");
293     return error;
294   }
295   range_info = info.getValue();
296   return error;
297 }
298 
299 void ProcessMinidump::Clear() { Process::m_thread_list.Clear(); }
300 
301 bool ProcessMinidump::UpdateThreadList(ThreadList &old_thread_list,
302                                        ThreadList &new_thread_list) {
303   uint32_t num_threads = 0;
304   if (m_thread_list.size() > 0)
305     num_threads = m_thread_list.size();
306 
307   for (lldb::tid_t tid = 0; tid < num_threads; ++tid) {
308     llvm::ArrayRef<uint8_t> context;
309     if (!m_is_wow64)
310       context = m_minidump_parser.GetThreadContext(m_thread_list[tid]);
311     else
312       context = m_minidump_parser.GetThreadContextWow64(m_thread_list[tid]);
313 
314     lldb::ThreadSP thread_sp(
315         new ThreadMinidump(*this, m_thread_list[tid], context));
316     new_thread_list.AddThread(thread_sp);
317   }
318   return new_thread_list.GetSize(false) > 0;
319 }
320 
321 void ProcessMinidump::ReadModuleList() {
322   std::vector<const MinidumpModule *> filtered_modules =
323       m_minidump_parser.GetFilteredModuleList();
324 
325   for (auto module : filtered_modules) {
326     llvm::Optional<std::string> name =
327         m_minidump_parser.GetMinidumpString(module->module_name_rva);
328 
329     if (!name)
330       continue;
331 
332     Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_MODULES));
333     if (log) {
334       log->Printf("ProcessMinidump::%s found module: name: %s %#010" PRIx64
335                   "-%#010" PRIx64 " size: %" PRIu32,
336                   __FUNCTION__, name.getValue().c_str(),
337                   uint64_t(module->base_of_image),
338                   module->base_of_image + module->size_of_image,
339                   uint32_t(module->size_of_image));
340     }
341 
342     // check if the process is wow64 - a 32 bit windows process running on a
343     // 64 bit windows
344     if (llvm::StringRef(name.getValue()).endswith_lower("wow64.dll")) {
345       m_is_wow64 = true;
346     }
347 
348     const auto uuid = m_minidump_parser.GetModuleUUID(module);
349     auto file_spec = FileSpec(name.getValue(), GetArchitecture().GetTriple());
350     FileSystem::Instance().Resolve(file_spec);
351     ModuleSpec module_spec(file_spec, uuid);
352     Status error;
353     lldb::ModuleSP module_sp = GetTarget().GetSharedModule(module_spec, &error);
354     if (!module_sp || error.Fail()) {
355       // We failed to locate a matching local object file. Fortunately, the
356       // minidump format encodes enough information about each module's memory
357       // range to allow us to create placeholder modules.
358       //
359       // This enables most LLDB functionality involving address-to-module
360       // translations (ex. identifing the module for a stack frame PC) and
361       // modules/sections commands (ex. target modules list, ...)
362       if (log) {
363         log->Printf("Unable to locate the matching object file, creating a "
364                     "placeholder module for: %s",
365                     name.getValue().c_str());
366       }
367 
368       auto placeholder_module =
369           std::make_shared<PlaceholderModule>(module_spec);
370       placeholder_module->CreateImageSection(module, GetTarget());
371       module_sp = placeholder_module;
372       GetTarget().GetImages().Append(module_sp);
373     }
374 
375     if (log) {
376       log->Printf("ProcessMinidump::%s load module: name: %s", __FUNCTION__,
377                   name.getValue().c_str());
378     }
379 
380     bool load_addr_changed = false;
381     module_sp->SetLoadAddress(GetTarget(), module->base_of_image, false,
382                               load_addr_changed);
383   }
384 }
385 
386 bool ProcessMinidump::GetProcessInfo(ProcessInstanceInfo &info) {
387   info.Clear();
388   info.SetProcessID(GetID());
389   info.SetArchitecture(GetArchitecture());
390   lldb::ModuleSP module_sp = GetTarget().GetExecutableModule();
391   if (module_sp) {
392     const bool add_exe_file_as_first_arg = false;
393     info.SetExecutableFile(GetTarget().GetExecutableModule()->GetFileSpec(),
394                            add_exe_file_as_first_arg);
395   }
396   return true;
397 }
398 
399 // For minidumps there's no runtime generated code so we don't need JITLoader(s)
400 // Avoiding them will also speed up minidump loading since JITLoaders normally
401 // try to set up symbolic breakpoints, which in turn may force loading more
402 // debug information than needed.
403 JITLoaderList &ProcessMinidump::GetJITLoaders() {
404   if (!m_jit_loaders_ap) {
405     m_jit_loaders_ap = llvm::make_unique<JITLoaderList>();
406   }
407   return *m_jit_loaders_ap;
408 }
409