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