1 //===-- ProcessMachCore.cpp -----------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include <cerrno>
10 #include <cstdlib>
11 
12 #include "llvm/Support/MathExtras.h"
13 #include "llvm/Support/Threading.h"
14 
15 #include "lldb/Core/Debugger.h"
16 #include "lldb/Core/Module.h"
17 #include "lldb/Core/ModuleSpec.h"
18 #include "lldb/Core/PluginManager.h"
19 #include "lldb/Core/Section.h"
20 #include "lldb/Host/Host.h"
21 #include "lldb/Symbol/LocateSymbolFile.h"
22 #include "lldb/Symbol/ObjectFile.h"
23 #include "lldb/Target/MemoryRegionInfo.h"
24 #include "lldb/Target/SectionLoadList.h"
25 #include "lldb/Target/Target.h"
26 #include "lldb/Target/Thread.h"
27 #include "lldb/Utility/DataBuffer.h"
28 #include "lldb/Utility/Log.h"
29 #include "lldb/Utility/State.h"
30 
31 #include "ProcessMachCore.h"
32 #include "Plugins/Process/Utility/StopInfoMachException.h"
33 #include "ThreadMachCore.h"
34 
35 // Needed for the plug-in names for the dynamic loaders.
36 #include "lldb/Host/SafeMachO.h"
37 
38 #include "Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.h"
39 #include "Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.h"
40 #include "Plugins/DynamicLoader/Static/DynamicLoaderStatic.h"
41 #include "Plugins/ObjectFile/Mach-O/ObjectFileMachO.h"
42 
43 #include <memory>
44 #include <mutex>
45 
46 using namespace lldb;
47 using namespace lldb_private;
48 
49 LLDB_PLUGIN_DEFINE(ProcessMachCore)
50 
51 llvm::StringRef ProcessMachCore::GetPluginDescriptionStatic() {
52   return "Mach-O core file debugging plug-in.";
53 }
54 
55 void ProcessMachCore::Terminate() {
56   PluginManager::UnregisterPlugin(ProcessMachCore::CreateInstance);
57 }
58 
59 lldb::ProcessSP ProcessMachCore::CreateInstance(lldb::TargetSP target_sp,
60                                                 ListenerSP listener_sp,
61                                                 const FileSpec *crash_file,
62                                                 bool can_connect) {
63   lldb::ProcessSP process_sp;
64   if (crash_file && !can_connect) {
65     const size_t header_size = sizeof(llvm::MachO::mach_header);
66     auto data_sp = FileSystem::Instance().CreateDataBuffer(
67         crash_file->GetPath(), header_size, 0);
68     if (data_sp && data_sp->GetByteSize() == header_size) {
69       DataExtractor data(data_sp, lldb::eByteOrderLittle, 4);
70 
71       lldb::offset_t data_offset = 0;
72       llvm::MachO::mach_header mach_header;
73       if (ObjectFileMachO::ParseHeader(data, &data_offset, mach_header)) {
74         if (mach_header.filetype == llvm::MachO::MH_CORE)
75           process_sp = std::make_shared<ProcessMachCore>(target_sp, listener_sp,
76                                                          *crash_file);
77       }
78     }
79   }
80   return process_sp;
81 }
82 
83 bool ProcessMachCore::CanDebug(lldb::TargetSP target_sp,
84                                bool plugin_specified_by_name) {
85   if (plugin_specified_by_name)
86     return true;
87 
88   // For now we are just making sure the file exists for a given module
89   if (!m_core_module_sp && FileSystem::Instance().Exists(m_core_file)) {
90     // Don't add the Target's architecture to the ModuleSpec - we may be
91     // working with a core file that doesn't have the correct cpusubtype in the
92     // header but we should still try to use it -
93     // ModuleSpecList::FindMatchingModuleSpec enforces a strict arch mach.
94     ModuleSpec core_module_spec(m_core_file);
95     Status error(ModuleList::GetSharedModule(core_module_spec, m_core_module_sp,
96                                              nullptr, nullptr, nullptr));
97 
98     if (m_core_module_sp) {
99       ObjectFile *core_objfile = m_core_module_sp->GetObjectFile();
100       if (core_objfile && core_objfile->GetType() == ObjectFile::eTypeCoreFile)
101         return true;
102     }
103   }
104   return false;
105 }
106 
107 // ProcessMachCore constructor
108 ProcessMachCore::ProcessMachCore(lldb::TargetSP target_sp,
109                                  ListenerSP listener_sp,
110                                  const FileSpec &core_file)
111     : PostMortemProcess(target_sp, listener_sp), m_core_aranges(),
112       m_core_range_infos(), m_core_module_sp(), m_core_file(core_file),
113       m_dyld_addr(LLDB_INVALID_ADDRESS),
114       m_mach_kernel_addr(LLDB_INVALID_ADDRESS) {}
115 
116 // Destructor
117 ProcessMachCore::~ProcessMachCore() {
118   Clear();
119   // We need to call finalize on the process before destroying ourselves to
120   // make sure all of the broadcaster cleanup goes as planned. If we destruct
121   // this class, then Process::~Process() might have problems trying to fully
122   // destroy the broadcaster.
123   Finalize();
124 }
125 
126 bool ProcessMachCore::GetDynamicLoaderAddress(lldb::addr_t addr) {
127   Log *log(GetLog(LLDBLog::DynamicLoader | LLDBLog::Process));
128   llvm::MachO::mach_header header;
129   Status error;
130   if (DoReadMemory(addr, &header, sizeof(header), error) != sizeof(header))
131     return false;
132   if (header.magic == llvm::MachO::MH_CIGAM ||
133       header.magic == llvm::MachO::MH_CIGAM_64) {
134     header.magic = llvm::ByteSwap_32(header.magic);
135     header.cputype = llvm::ByteSwap_32(header.cputype);
136     header.cpusubtype = llvm::ByteSwap_32(header.cpusubtype);
137     header.filetype = llvm::ByteSwap_32(header.filetype);
138     header.ncmds = llvm::ByteSwap_32(header.ncmds);
139     header.sizeofcmds = llvm::ByteSwap_32(header.sizeofcmds);
140     header.flags = llvm::ByteSwap_32(header.flags);
141   }
142 
143   // TODO: swap header if needed...
144   // printf("0x%16.16" PRIx64 ": magic = 0x%8.8x, file_type= %u\n", vaddr,
145   // header.magic, header.filetype);
146   if (header.magic == llvm::MachO::MH_MAGIC ||
147       header.magic == llvm::MachO::MH_MAGIC_64) {
148     // Check MH_EXECUTABLE to see if we can find the mach image that contains
149     // the shared library list. The dynamic loader (dyld) is what contains the
150     // list for user applications, and the mach kernel contains a global that
151     // has the list of kexts to load
152     switch (header.filetype) {
153     case llvm::MachO::MH_DYLINKER:
154       // printf("0x%16.16" PRIx64 ": file_type = MH_DYLINKER\n", vaddr);
155       // Address of dyld "struct mach_header" in the core file
156       LLDB_LOGF(log,
157                 "ProcessMachCore::GetDynamicLoaderAddress found a user "
158                 "process dyld binary image at 0x%" PRIx64,
159                 addr);
160       m_dyld_addr = addr;
161       return true;
162 
163     case llvm::MachO::MH_EXECUTE:
164       // printf("0x%16.16" PRIx64 ": file_type = MH_EXECUTE\n", vaddr);
165       // Check MH_EXECUTABLE file types to see if the dynamic link object flag
166       // is NOT set. If it isn't, then we have a mach_kernel.
167       if ((header.flags & llvm::MachO::MH_DYLDLINK) == 0) {
168         LLDB_LOGF(log,
169                   "ProcessMachCore::GetDynamicLoaderAddress found a mach "
170                   "kernel binary image at 0x%" PRIx64,
171                   addr);
172         // Address of the mach kernel "struct mach_header" in the core file.
173         m_mach_kernel_addr = addr;
174         return true;
175       }
176       break;
177     }
178   }
179   return false;
180 }
181 
182 // We have a hint about a binary -- a UUID, possibly a load address.
183 // Try to load a file with that UUID into lldb, and if we have a load
184 // address, set it correctly.  Else assume that the binary was loaded
185 // with no slide.
186 static bool load_standalone_binary(UUID uuid, addr_t value,
187                                    bool value_is_offset, Target &target) {
188   if (uuid.IsValid()) {
189     ModuleSpec module_spec;
190     module_spec.GetUUID() = uuid;
191 
192     // Look up UUID in global module cache before attempting
193     // dsymForUUID-like action.
194     ModuleSP module_sp;
195     Status error = ModuleList::GetSharedModule(module_spec, module_sp, nullptr,
196                                                nullptr, nullptr);
197 
198     if (!module_sp.get()) {
199       // Force a a dsymForUUID lookup, if that tool is available.
200       if (!module_spec.GetSymbolFileSpec())
201         Symbols::DownloadObjectAndSymbolFile(module_spec, true);
202 
203       if (FileSystem::Instance().Exists(module_spec.GetFileSpec())) {
204         module_sp = std::make_shared<Module>(module_spec);
205       }
206     }
207 
208     // If we couldn't find the binary anywhere else, as a last resort,
209     // read it out of memory in the corefile.
210     if (!module_sp.get() && value != LLDB_INVALID_ADDRESS && !value_is_offset) {
211       char namebuf[80];
212       snprintf(namebuf, sizeof(namebuf), "mem-image-0x%" PRIx64, value);
213       module_sp =
214           target.GetProcessSP()->ReadModuleFromMemory(FileSpec(namebuf), value);
215     }
216 
217     if (module_sp.get()) {
218       target.SetArchitecture(module_sp->GetObjectFile()->GetArchitecture());
219       target.GetImages().AppendIfNeeded(module_sp, false);
220 
221       bool changed = false;
222       if (module_sp->GetObjectFile()) {
223         if (value != LLDB_INVALID_ADDRESS) {
224           module_sp->SetLoadAddress(target, value, value_is_offset, changed);
225         } else {
226           // No address/offset/slide, load the binary at file address,
227           // offset 0.
228           const bool value_is_slide = true;
229           module_sp->SetLoadAddress(target, 0, value_is_slide, changed);
230         }
231       } else {
232         // In-memory image, load at its true address, offset 0.
233         const bool value_is_slide = true;
234         module_sp->SetLoadAddress(target, 0, value_is_slide, changed);
235       }
236 
237       ModuleList added_module;
238       added_module.Append(module_sp, false);
239       target.ModulesDidLoad(added_module);
240 
241       // Flush info in the process (stack frames, etc).
242       ProcessSP process_sp(target.GetProcessSP());
243       if (process_sp)
244         process_sp->Flush();
245 
246       return true;
247     }
248   }
249   return false;
250 }
251 
252 // Process Control
253 Status ProcessMachCore::DoLoadCore() {
254   Log *log(GetLog(LLDBLog::DynamicLoader | LLDBLog::Process));
255   Status error;
256   if (!m_core_module_sp) {
257     error.SetErrorString("invalid core module");
258     return error;
259   }
260 
261   ObjectFile *core_objfile = m_core_module_sp->GetObjectFile();
262   if (core_objfile == nullptr) {
263     error.SetErrorString("invalid core object file");
264     return error;
265   }
266 
267   if (core_objfile->GetNumThreadContexts() == 0) {
268     error.SetErrorString("core file doesn't contain any LC_THREAD load "
269                          "commands, or the LC_THREAD architecture is not "
270                          "supported in this lldb");
271     return error;
272   }
273 
274   SectionList *section_list = core_objfile->GetSectionList();
275   if (section_list == nullptr) {
276     error.SetErrorString("core file has no sections");
277     return error;
278   }
279 
280   const uint32_t num_sections = section_list->GetNumSections(0);
281   if (num_sections == 0) {
282     error.SetErrorString("core file has no sections");
283     return error;
284   }
285 
286   SetCanJIT(false);
287 
288   llvm::MachO::mach_header header;
289   DataExtractor data(&header, sizeof(header),
290                      m_core_module_sp->GetArchitecture().GetByteOrder(),
291                      m_core_module_sp->GetArchitecture().GetAddressByteSize());
292 
293   bool ranges_are_sorted = true;
294   addr_t vm_addr = 0;
295   for (uint32_t i = 0; i < num_sections; ++i) {
296     Section *section = section_list->GetSectionAtIndex(i).get();
297     if (section && section->GetFileSize() > 0) {
298       lldb::addr_t section_vm_addr = section->GetFileAddress();
299       FileRange file_range(section->GetFileOffset(), section->GetFileSize());
300       VMRangeToFileOffset::Entry range_entry(
301           section_vm_addr, section->GetByteSize(), file_range);
302 
303       if (vm_addr > section_vm_addr)
304         ranges_are_sorted = false;
305       vm_addr = section->GetFileAddress();
306       VMRangeToFileOffset::Entry *last_entry = m_core_aranges.Back();
307 
308       if (last_entry &&
309           last_entry->GetRangeEnd() == range_entry.GetRangeBase() &&
310           last_entry->data.GetRangeEnd() == range_entry.data.GetRangeBase()) {
311         last_entry->SetRangeEnd(range_entry.GetRangeEnd());
312         last_entry->data.SetRangeEnd(range_entry.data.GetRangeEnd());
313       } else {
314         m_core_aranges.Append(range_entry);
315       }
316       // Some core files don't fill in the permissions correctly. If that is
317       // the case assume read + execute so clients don't think the memory is
318       // not readable, or executable. The memory isn't writable since this
319       // plug-in doesn't implement DoWriteMemory.
320       uint32_t permissions = section->GetPermissions();
321       if (permissions == 0)
322         permissions = lldb::ePermissionsReadable | lldb::ePermissionsExecutable;
323       m_core_range_infos.Append(VMRangeToPermissions::Entry(
324           section_vm_addr, section->GetByteSize(), permissions));
325     }
326   }
327   if (!ranges_are_sorted) {
328     m_core_aranges.Sort();
329     m_core_range_infos.Sort();
330   }
331 
332   bool found_main_binary_definitively = false;
333 
334   addr_t objfile_binary_value;
335   bool objfile_binary_value_is_offset;
336   UUID objfile_binary_uuid;
337   ObjectFile::BinaryType type;
338   if (core_objfile->GetCorefileMainBinaryInfo(objfile_binary_value,
339                                               objfile_binary_value_is_offset,
340                                               objfile_binary_uuid, type)) {
341     if (log) {
342       log->Printf(
343           "ProcessMachCore::DoLoadCore: using binary hint from 'main bin spec' "
344           "LC_NOTE with UUID %s value 0x%" PRIx64
345           " value is offset %d and type %d",
346           objfile_binary_uuid.GetAsString().c_str(), objfile_binary_value,
347           objfile_binary_value_is_offset, type);
348     }
349     if (objfile_binary_value != LLDB_INVALID_ADDRESS &&
350         !objfile_binary_value_is_offset) {
351       if (type == ObjectFile::eBinaryTypeUser) {
352         m_dyld_addr = objfile_binary_value;
353         m_dyld_plugin_name = DynamicLoaderMacOSXDYLD::GetPluginNameStatic();
354         found_main_binary_definitively = true;
355       }
356       if (type == ObjectFile::eBinaryTypeKernel) {
357         m_mach_kernel_addr = objfile_binary_value;
358         m_dyld_plugin_name = DynamicLoaderDarwinKernel::GetPluginNameStatic();
359         found_main_binary_definitively = true;
360       }
361     }
362     if (!found_main_binary_definitively) {
363       // ObjectFile::eBinaryTypeStandalone, undeclared types
364       if (load_standalone_binary(objfile_binary_uuid, objfile_binary_value,
365                                  objfile_binary_value_is_offset, GetTarget())) {
366         found_main_binary_definitively = true;
367         m_dyld_plugin_name = DynamicLoaderStatic::GetPluginNameStatic();
368       }
369     }
370   }
371 
372   // This checks for the presence of an LC_IDENT string in a core file;
373   // LC_IDENT is very obsolete and should not be used in new code, but if the
374   // load command is present, let's use the contents.
375   UUID ident_uuid;
376   addr_t ident_binary_addr = LLDB_INVALID_ADDRESS;
377   if (!found_main_binary_definitively) {
378     std::string corefile_identifier = core_objfile->GetIdentifierString();
379 
380     // Search for UUID= and stext= strings in the identifier str.
381     if (corefile_identifier.find("UUID=") != std::string::npos) {
382       size_t p = corefile_identifier.find("UUID=") + strlen("UUID=");
383       std::string uuid_str = corefile_identifier.substr(p, 36);
384       ident_uuid.SetFromStringRef(uuid_str);
385       if (log)
386         log->Printf("Got a UUID from LC_IDENT/kern ver str LC_NOTE: %s",
387                     ident_uuid.GetAsString().c_str());
388     }
389     if (corefile_identifier.find("stext=") != std::string::npos) {
390       size_t p = corefile_identifier.find("stext=") + strlen("stext=");
391       if (corefile_identifier[p] == '0' && corefile_identifier[p + 1] == 'x') {
392         ident_binary_addr =
393             ::strtoul(corefile_identifier.c_str() + p, nullptr, 16);
394         if (log)
395           log->Printf("Got a load address from LC_IDENT/kern ver str "
396                       "LC_NOTE: 0x%" PRIx64,
397                       ident_binary_addr);
398       }
399     }
400 
401     // Search for a "Darwin Kernel" str indicating kernel; else treat as
402     // standalone
403     if (corefile_identifier.find("Darwin Kernel") != std::string::npos &&
404         ident_uuid.IsValid() && ident_binary_addr != LLDB_INVALID_ADDRESS) {
405       if (log)
406         log->Printf("ProcessMachCore::DoLoadCore: Found kernel binary via "
407                     "LC_IDENT/kern ver str LC_NOTE");
408       m_mach_kernel_addr = ident_binary_addr;
409       found_main_binary_definitively = true;
410     } else if (ident_uuid.IsValid()) {
411       // We have no address specified, only a UUID.  Load it at the file
412       // address.
413       const bool value_is_offset = false;
414       if (load_standalone_binary(ident_uuid, ident_binary_addr, value_is_offset,
415                                  GetTarget())) {
416         found_main_binary_definitively = true;
417         m_dyld_plugin_name = DynamicLoaderStatic::GetPluginNameStatic();
418       }
419     }
420   }
421 
422   bool did_load_extra_binaries = core_objfile->LoadCoreFileImages(*this);
423   // If we have a "all image infos" LC_NOTE, try to load all of the
424   // binaries listed, and set their Section load addresses in the Target.
425   if (found_main_binary_definitively == false && did_load_extra_binaries) {
426     m_dyld_plugin_name = DynamicLoaderDarwinKernel::GetPluginNameStatic();
427     found_main_binary_definitively = true;
428   }
429 
430   if (!found_main_binary_definitively &&
431       (m_dyld_addr == LLDB_INVALID_ADDRESS ||
432        m_mach_kernel_addr == LLDB_INVALID_ADDRESS)) {
433     // We need to locate the main executable in the memory ranges we have in
434     // the core file.  We need to search for both a user-process dyld binary
435     // and a kernel binary in memory; we must look at all the pages in the
436     // binary so we don't miss one or the other.  Step through all memory
437     // segments searching for a kernel binary and for a user process dyld --
438     // we'll decide which to prefer later if both are present.
439 
440     const size_t num_core_aranges = m_core_aranges.GetSize();
441     for (size_t i = 0; i < num_core_aranges; ++i) {
442       const VMRangeToFileOffset::Entry *entry =
443           m_core_aranges.GetEntryAtIndex(i);
444       lldb::addr_t section_vm_addr_start = entry->GetRangeBase();
445       lldb::addr_t section_vm_addr_end = entry->GetRangeEnd();
446       for (lldb::addr_t section_vm_addr = section_vm_addr_start;
447            section_vm_addr < section_vm_addr_end; section_vm_addr += 0x1000) {
448         GetDynamicLoaderAddress(section_vm_addr);
449       }
450     }
451   }
452 
453   if (!found_main_binary_definitively &&
454       m_mach_kernel_addr != LLDB_INVALID_ADDRESS) {
455     // In the case of multiple kernel images found in the core file via
456     // exhaustive search, we may not pick the correct one.  See if the
457     // DynamicLoaderDarwinKernel's search heuristics might identify the correct
458     // one. Most of the time, I expect the address from SearchForDarwinKernel()
459     // will be the same as the address we found via exhaustive search.
460 
461     if (!GetTarget().GetArchitecture().IsValid() && m_core_module_sp.get()) {
462       GetTarget().SetArchitecture(m_core_module_sp->GetArchitecture());
463     }
464 
465     // SearchForDarwinKernel will end up calling back into this this class in
466     // the GetImageInfoAddress method which will give it the
467     // m_mach_kernel_addr/m_dyld_addr it already has.  Save that aside and set
468     // m_mach_kernel_addr/m_dyld_addr to an invalid address temporarily so
469     // DynamicLoaderDarwinKernel does a real search for the kernel using its
470     // own heuristics.
471 
472     addr_t saved_mach_kernel_addr = m_mach_kernel_addr;
473     addr_t saved_user_dyld_addr = m_dyld_addr;
474     m_mach_kernel_addr = LLDB_INVALID_ADDRESS;
475     m_dyld_addr = LLDB_INVALID_ADDRESS;
476 
477     addr_t better_kernel_address =
478         DynamicLoaderDarwinKernel::SearchForDarwinKernel(this);
479 
480     m_mach_kernel_addr = saved_mach_kernel_addr;
481     m_dyld_addr = saved_user_dyld_addr;
482 
483     if (better_kernel_address != LLDB_INVALID_ADDRESS) {
484       LLDB_LOGF(log, "ProcessMachCore::DoLoadCore: Using the kernel address "
485                      "from DynamicLoaderDarwinKernel");
486       m_mach_kernel_addr = better_kernel_address;
487     }
488   }
489 
490   if (m_dyld_plugin_name.empty()) {
491     // If we found both a user-process dyld and a kernel binary, we need to
492     // decide which to prefer.
493     if (GetCorefilePreference() == eKernelCorefile) {
494       if (m_mach_kernel_addr != LLDB_INVALID_ADDRESS) {
495         LLDB_LOGF(log,
496                   "ProcessMachCore::DoLoadCore: Using kernel corefile image "
497                   "at 0x%" PRIx64,
498                   m_mach_kernel_addr);
499         m_dyld_plugin_name = DynamicLoaderDarwinKernel::GetPluginNameStatic();
500       } else if (m_dyld_addr != LLDB_INVALID_ADDRESS) {
501         LLDB_LOGF(log,
502                   "ProcessMachCore::DoLoadCore: Using user process dyld "
503                   "image at 0x%" PRIx64,
504                   m_dyld_addr);
505         m_dyld_plugin_name = DynamicLoaderMacOSXDYLD::GetPluginNameStatic();
506       }
507     } else {
508       if (m_dyld_addr != LLDB_INVALID_ADDRESS) {
509         LLDB_LOGF(log,
510                   "ProcessMachCore::DoLoadCore: Using user process dyld "
511                   "image at 0x%" PRIx64,
512                   m_dyld_addr);
513         m_dyld_plugin_name = DynamicLoaderMacOSXDYLD::GetPluginNameStatic();
514       } else if (m_mach_kernel_addr != LLDB_INVALID_ADDRESS) {
515         LLDB_LOGF(log,
516                   "ProcessMachCore::DoLoadCore: Using kernel corefile image "
517                   "at 0x%" PRIx64,
518                   m_mach_kernel_addr);
519         m_dyld_plugin_name = DynamicLoaderDarwinKernel::GetPluginNameStatic();
520       }
521     }
522   }
523 
524   if (m_dyld_plugin_name != DynamicLoaderMacOSXDYLD::GetPluginNameStatic()) {
525     // For non-user process core files, the permissions on the core file
526     // segments are usually meaningless, they may be just "read", because we're
527     // dealing with kernel coredumps or early startup coredumps and the dumper
528     // is grabbing pages of memory without knowing what they are.  If they
529     // aren't marked as "executable", that can break the unwinder which will
530     // check a pc value to see if it is in an executable segment and stop the
531     // backtrace early if it is not ("executable" and "unknown" would both be
532     // fine, but "not executable" will break the unwinder).
533     size_t core_range_infos_size = m_core_range_infos.GetSize();
534     for (size_t i = 0; i < core_range_infos_size; i++) {
535       VMRangeToPermissions::Entry *ent =
536           m_core_range_infos.GetMutableEntryAtIndex(i);
537       ent->data = lldb::ePermissionsReadable | lldb::ePermissionsExecutable;
538     }
539   }
540 
541   // Even if the architecture is set in the target, we need to override it to
542   // match the core file which is always single arch.
543   ArchSpec arch(m_core_module_sp->GetArchitecture());
544   if (arch.GetCore() == ArchSpec::eCore_x86_32_i486) {
545     arch = Platform::GetAugmentedArchSpec(GetTarget().GetPlatform().get(), "i386");
546   }
547   if (arch.IsValid())
548     GetTarget().SetArchitecture(arch);
549 
550   addr_t address_mask = core_objfile->GetAddressMask();
551   if (address_mask != 0) {
552     SetCodeAddressMask(address_mask);
553     SetDataAddressMask(address_mask);
554   }
555   return error;
556 }
557 
558 lldb_private::DynamicLoader *ProcessMachCore::GetDynamicLoader() {
559   if (m_dyld_up.get() == nullptr)
560     m_dyld_up.reset(DynamicLoader::FindPlugin(this, m_dyld_plugin_name));
561   return m_dyld_up.get();
562 }
563 
564 bool ProcessMachCore::DoUpdateThreadList(ThreadList &old_thread_list,
565                                          ThreadList &new_thread_list) {
566   if (old_thread_list.GetSize(false) == 0) {
567     // Make up the thread the first time this is called so we can setup our one
568     // and only core thread state.
569     ObjectFile *core_objfile = m_core_module_sp->GetObjectFile();
570 
571     if (core_objfile) {
572       const uint32_t num_threads = core_objfile->GetNumThreadContexts();
573       for (lldb::tid_t tid = 0; tid < num_threads; ++tid) {
574         ThreadSP thread_sp(new ThreadMachCore(*this, tid));
575         new_thread_list.AddThread(thread_sp);
576       }
577     }
578   } else {
579     const uint32_t num_threads = old_thread_list.GetSize(false);
580     for (uint32_t i = 0; i < num_threads; ++i)
581       new_thread_list.AddThread(old_thread_list.GetThreadAtIndex(i, false));
582   }
583   return new_thread_list.GetSize(false) > 0;
584 }
585 
586 void ProcessMachCore::RefreshStateAfterStop() {
587   // Let all threads recover from stopping and do any clean up based on the
588   // previous thread state (if any).
589   m_thread_list.RefreshStateAfterStop();
590   // SetThreadStopInfo (m_last_stop_packet);
591 }
592 
593 Status ProcessMachCore::DoDestroy() { return Status(); }
594 
595 // Process Queries
596 
597 bool ProcessMachCore::IsAlive() { return true; }
598 
599 bool ProcessMachCore::WarnBeforeDetach() const { return false; }
600 
601 // Process Memory
602 size_t ProcessMachCore::ReadMemory(addr_t addr, void *buf, size_t size,
603                                    Status &error) {
604   // Don't allow the caching that lldb_private::Process::ReadMemory does since
605   // in core files we have it all cached our our core file anyway.
606   return DoReadMemory(addr, buf, size, error);
607 }
608 
609 size_t ProcessMachCore::DoReadMemory(addr_t addr, void *buf, size_t size,
610                                      Status &error) {
611   ObjectFile *core_objfile = m_core_module_sp->GetObjectFile();
612   size_t bytes_read = 0;
613 
614   if (core_objfile) {
615     // Segments are not always contiguous in mach-o core files. We have core
616     // files that have segments like:
617     //            Address    Size       File off   File size
618     //            ---------- ---------- ---------- ----------
619     // LC_SEGMENT 0x000f6000 0x00001000 0x1d509ee8 0x00001000 --- ---   0
620     // 0x00000000 __TEXT LC_SEGMENT 0x0f600000 0x00100000 0x1d50aee8 0x00100000
621     // --- ---   0 0x00000000 __TEXT LC_SEGMENT 0x000f7000 0x00001000
622     // 0x1d60aee8 0x00001000 --- ---   0 0x00000000 __TEXT
623     //
624     // Any if the user executes the following command:
625     //
626     // (lldb) mem read 0xf6ff0
627     //
628     // We would attempt to read 32 bytes from 0xf6ff0 but would only get 16
629     // unless we loop through consecutive memory ranges that are contiguous in
630     // the address space, but not in the file data.
631     while (bytes_read < size) {
632       const addr_t curr_addr = addr + bytes_read;
633       const VMRangeToFileOffset::Entry *core_memory_entry =
634           m_core_aranges.FindEntryThatContains(curr_addr);
635 
636       if (core_memory_entry) {
637         const addr_t offset = curr_addr - core_memory_entry->GetRangeBase();
638         const addr_t bytes_left = core_memory_entry->GetRangeEnd() - curr_addr;
639         const size_t bytes_to_read =
640             std::min(size - bytes_read, (size_t)bytes_left);
641         const size_t curr_bytes_read = core_objfile->CopyData(
642             core_memory_entry->data.GetRangeBase() + offset, bytes_to_read,
643             (char *)buf + bytes_read);
644         if (curr_bytes_read == 0)
645           break;
646         bytes_read += curr_bytes_read;
647       } else {
648         // Only set the error if we didn't read any bytes
649         if (bytes_read == 0)
650           error.SetErrorStringWithFormat(
651               "core file does not contain 0x%" PRIx64, curr_addr);
652         break;
653       }
654     }
655   }
656 
657   return bytes_read;
658 }
659 
660 Status ProcessMachCore::GetMemoryRegionInfo(addr_t load_addr,
661                                             MemoryRegionInfo &region_info) {
662   region_info.Clear();
663   const VMRangeToPermissions::Entry *permission_entry =
664       m_core_range_infos.FindEntryThatContainsOrFollows(load_addr);
665   if (permission_entry) {
666     if (permission_entry->Contains(load_addr)) {
667       region_info.GetRange().SetRangeBase(permission_entry->GetRangeBase());
668       region_info.GetRange().SetRangeEnd(permission_entry->GetRangeEnd());
669       const Flags permissions(permission_entry->data);
670       region_info.SetReadable(permissions.Test(ePermissionsReadable)
671                                   ? MemoryRegionInfo::eYes
672                                   : MemoryRegionInfo::eNo);
673       region_info.SetWritable(permissions.Test(ePermissionsWritable)
674                                   ? MemoryRegionInfo::eYes
675                                   : MemoryRegionInfo::eNo);
676       region_info.SetExecutable(permissions.Test(ePermissionsExecutable)
677                                     ? MemoryRegionInfo::eYes
678                                     : MemoryRegionInfo::eNo);
679       region_info.SetMapped(MemoryRegionInfo::eYes);
680     } else if (load_addr < permission_entry->GetRangeBase()) {
681       region_info.GetRange().SetRangeBase(load_addr);
682       region_info.GetRange().SetRangeEnd(permission_entry->GetRangeBase());
683       region_info.SetReadable(MemoryRegionInfo::eNo);
684       region_info.SetWritable(MemoryRegionInfo::eNo);
685       region_info.SetExecutable(MemoryRegionInfo::eNo);
686       region_info.SetMapped(MemoryRegionInfo::eNo);
687     }
688     return Status();
689   }
690 
691   region_info.GetRange().SetRangeBase(load_addr);
692   region_info.GetRange().SetRangeEnd(LLDB_INVALID_ADDRESS);
693   region_info.SetReadable(MemoryRegionInfo::eNo);
694   region_info.SetWritable(MemoryRegionInfo::eNo);
695   region_info.SetExecutable(MemoryRegionInfo::eNo);
696   region_info.SetMapped(MemoryRegionInfo::eNo);
697   return Status();
698 }
699 
700 void ProcessMachCore::Clear() { m_thread_list.Clear(); }
701 
702 void ProcessMachCore::Initialize() {
703   static llvm::once_flag g_once_flag;
704 
705   llvm::call_once(g_once_flag, []() {
706     PluginManager::RegisterPlugin(GetPluginNameStatic(),
707                                   GetPluginDescriptionStatic(), CreateInstance);
708   });
709 }
710 
711 addr_t ProcessMachCore::GetImageInfoAddress() {
712   // If we found both a user-process dyld and a kernel binary, we need to
713   // decide which to prefer.
714   if (GetCorefilePreference() == eKernelCorefile) {
715     if (m_mach_kernel_addr != LLDB_INVALID_ADDRESS) {
716       return m_mach_kernel_addr;
717     }
718     return m_dyld_addr;
719   } else {
720     if (m_dyld_addr != LLDB_INVALID_ADDRESS) {
721       return m_dyld_addr;
722     }
723     return m_mach_kernel_addr;
724   }
725 }
726 
727 lldb_private::ObjectFile *ProcessMachCore::GetCoreObjectFile() {
728   return m_core_module_sp->GetObjectFile();
729 }
730