1 //===-- DynamicLoaderPOSIXDYLD.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 // Main header include
10 #include "DynamicLoaderPOSIXDYLD.h"
11 
12 #include "lldb/Breakpoint/BreakpointLocation.h"
13 #include "lldb/Core/Module.h"
14 #include "lldb/Core/ModuleSpec.h"
15 #include "lldb/Core/PluginManager.h"
16 #include "lldb/Core/Section.h"
17 #include "lldb/Symbol/Function.h"
18 #include "lldb/Symbol/ObjectFile.h"
19 #include "lldb/Target/MemoryRegionInfo.h"
20 #include "lldb/Target/Platform.h"
21 #include "lldb/Target/Target.h"
22 #include "lldb/Target/Thread.h"
23 #include "lldb/Target/ThreadPlanRunToAddress.h"
24 #include "lldb/Utility/LLDBLog.h"
25 #include "lldb/Utility/Log.h"
26 #include "lldb/Utility/ProcessInfo.h"
27 
28 #include <memory>
29 #include <optional>
30 
31 using namespace lldb;
32 using namespace lldb_private;
33 
LLDB_PLUGIN_DEFINE_ADV(DynamicLoaderPOSIXDYLD,DynamicLoaderPosixDYLD)34 LLDB_PLUGIN_DEFINE_ADV(DynamicLoaderPOSIXDYLD, DynamicLoaderPosixDYLD)
35 
36 void DynamicLoaderPOSIXDYLD::Initialize() {
37   PluginManager::RegisterPlugin(GetPluginNameStatic(),
38                                 GetPluginDescriptionStatic(), CreateInstance);
39 }
40 
Terminate()41 void DynamicLoaderPOSIXDYLD::Terminate() {}
42 
GetPluginDescriptionStatic()43 llvm::StringRef DynamicLoaderPOSIXDYLD::GetPluginDescriptionStatic() {
44   return "Dynamic loader plug-in that watches for shared library "
45          "loads/unloads in POSIX processes.";
46 }
47 
CreateInstance(Process * process,bool force)48 DynamicLoader *DynamicLoaderPOSIXDYLD::CreateInstance(Process *process,
49                                                       bool force) {
50   bool create = force;
51   if (!create) {
52     const llvm::Triple &triple_ref =
53         process->GetTarget().GetArchitecture().GetTriple();
54     if (triple_ref.getOS() == llvm::Triple::FreeBSD ||
55         triple_ref.getOS() == llvm::Triple::Linux ||
56         triple_ref.getOS() == llvm::Triple::NetBSD ||
57         triple_ref.getOS() == llvm::Triple::OpenBSD)
58       create = true;
59   }
60 
61   if (create)
62     return new DynamicLoaderPOSIXDYLD(process);
63   return nullptr;
64 }
65 
DynamicLoaderPOSIXDYLD(Process * process)66 DynamicLoaderPOSIXDYLD::DynamicLoaderPOSIXDYLD(Process *process)
67     : DynamicLoader(process), m_rendezvous(process),
68       m_load_offset(LLDB_INVALID_ADDRESS), m_entry_point(LLDB_INVALID_ADDRESS),
69       m_auxv(), m_dyld_bid(LLDB_INVALID_BREAK_ID),
70       m_vdso_base(LLDB_INVALID_ADDRESS),
71       m_interpreter_base(LLDB_INVALID_ADDRESS), m_initial_modules_added(false) {
72 }
73 
~DynamicLoaderPOSIXDYLD()74 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD() {
75   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
76     m_process->GetTarget().RemoveBreakpointByID(m_dyld_bid);
77     m_dyld_bid = LLDB_INVALID_BREAK_ID;
78   }
79 }
80 
DidAttach()81 void DynamicLoaderPOSIXDYLD::DidAttach() {
82   Log *log = GetLog(LLDBLog::DynamicLoader);
83   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s() pid %" PRIu64, __FUNCTION__,
84             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
85   m_auxv = std::make_unique<AuxVector>(m_process->GetAuxvData());
86 
87   LLDB_LOGF(
88       log, "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " reloaded auxv data",
89       __FUNCTION__, m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
90 
91   ModuleSP executable_sp = GetTargetExecutable();
92   ResolveExecutableModule(executable_sp);
93   m_rendezvous.UpdateExecutablePath();
94 
95   // find the main process load offset
96   addr_t load_offset = ComputeLoadOffset();
97   LLDB_LOGF(log,
98             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
99             " executable '%s', load_offset 0x%" PRIx64,
100             __FUNCTION__,
101             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
102             executable_sp ? executable_sp->GetFileSpec().GetPath().c_str()
103                           : "<null executable>",
104             load_offset);
105 
106   EvalSpecialModulesStatus();
107 
108   // if we dont have a load address we cant re-base
109   bool rebase_exec = load_offset != LLDB_INVALID_ADDRESS;
110 
111   // if we have a valid executable
112   if (executable_sp.get()) {
113     lldb_private::ObjectFile *obj = executable_sp->GetObjectFile();
114     if (obj) {
115       // don't rebase if the module already has a load address
116       Target &target = m_process->GetTarget();
117       Address addr = obj->GetImageInfoAddress(&target);
118       if (addr.GetLoadAddress(&target) != LLDB_INVALID_ADDRESS)
119         rebase_exec = false;
120     }
121   } else {
122     // no executable, nothing to re-base
123     rebase_exec = false;
124   }
125 
126   // if the target executable should be re-based
127   if (rebase_exec) {
128     ModuleList module_list;
129 
130     module_list.Append(executable_sp);
131     LLDB_LOGF(log,
132               "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
133               " added executable '%s' to module load list",
134               __FUNCTION__,
135               m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
136               executable_sp->GetFileSpec().GetPath().c_str());
137 
138     UpdateLoadedSections(executable_sp, LLDB_INVALID_ADDRESS, load_offset,
139                          true);
140 
141     LoadAllCurrentModules();
142 
143     m_process->GetTarget().ModulesDidLoad(module_list);
144     if (log) {
145       LLDB_LOGF(log,
146                 "DynamicLoaderPOSIXDYLD::%s told the target about the "
147                 "modules that loaded:",
148                 __FUNCTION__);
149       for (auto module_sp : module_list.Modules()) {
150         LLDB_LOGF(log, "-- [module] %s (pid %" PRIu64 ")",
151                   module_sp ? module_sp->GetFileSpec().GetPath().c_str()
152                             : "<null>",
153                   m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
154       }
155     }
156   }
157 
158   if (executable_sp.get()) {
159     if (!SetRendezvousBreakpoint()) {
160       // If we cannot establish rendezvous breakpoint right now we'll try again
161       // at entry point.
162       ProbeEntry();
163     }
164   }
165 }
166 
DidLaunch()167 void DynamicLoaderPOSIXDYLD::DidLaunch() {
168   Log *log = GetLog(LLDBLog::DynamicLoader);
169   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s()", __FUNCTION__);
170 
171   ModuleSP executable;
172   addr_t load_offset;
173 
174   m_auxv = std::make_unique<AuxVector>(m_process->GetAuxvData());
175 
176   executable = GetTargetExecutable();
177   load_offset = ComputeLoadOffset();
178   EvalSpecialModulesStatus();
179 
180   if (executable.get() && load_offset != LLDB_INVALID_ADDRESS) {
181     ModuleList module_list;
182     module_list.Append(executable);
183     UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset, true);
184 
185     LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s about to call ProbeEntry()",
186               __FUNCTION__);
187 
188     if (!SetRendezvousBreakpoint()) {
189       // If we cannot establish rendezvous breakpoint right now we'll try again
190       // at entry point.
191       ProbeEntry();
192     }
193 
194     LoadVDSO();
195     m_process->GetTarget().ModulesDidLoad(module_list);
196   }
197 }
198 
CanLoadImage()199 Status DynamicLoaderPOSIXDYLD::CanLoadImage() { return Status(); }
200 
UpdateLoadedSections(ModuleSP module,addr_t link_map_addr,addr_t base_addr,bool base_addr_is_offset)201 void DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module,
202                                                   addr_t link_map_addr,
203                                                   addr_t base_addr,
204                                                   bool base_addr_is_offset) {
205   m_loaded_modules[module] = link_map_addr;
206   UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset);
207 }
208 
UnloadSections(const ModuleSP module)209 void DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module) {
210   m_loaded_modules.erase(module);
211 
212   UnloadSectionsCommon(module);
213 }
214 
ProbeEntry()215 void DynamicLoaderPOSIXDYLD::ProbeEntry() {
216   Log *log = GetLog(LLDBLog::DynamicLoader);
217 
218   // If we have a core file, we don't need any breakpoints.
219   if (IsCoreFile())
220     return;
221 
222   const addr_t entry = GetEntryPoint();
223   if (entry == LLDB_INVALID_ADDRESS) {
224     LLDB_LOGF(
225         log,
226         "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
227         " GetEntryPoint() returned no address, not setting entry breakpoint",
228         __FUNCTION__, m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
229     return;
230   }
231 
232   LLDB_LOGF(log,
233             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
234             " GetEntryPoint() returned address 0x%" PRIx64
235             ", setting entry breakpoint",
236             __FUNCTION__,
237             m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID, entry);
238 
239   if (m_process) {
240     Breakpoint *const entry_break =
241         m_process->GetTarget().CreateBreakpoint(entry, true, false).get();
242     entry_break->SetCallback(EntryBreakpointHit, this, true);
243     entry_break->SetBreakpointKind("shared-library-event");
244 
245     // Shoudn't hit this more than once.
246     entry_break->SetOneShot(true);
247   }
248 }
249 
250 // The runtime linker has run and initialized the rendezvous structure once the
251 // process has hit its entry point.  When we hit the corresponding breakpoint
252 // we interrogate the rendezvous structure to get the load addresses of all
253 // dependent modules for the process.  Similarly, we can discover the runtime
254 // linker function and setup a breakpoint to notify us of any dynamically
255 // loaded modules (via dlopen).
EntryBreakpointHit(void * baton,StoppointCallbackContext * context,user_id_t break_id,user_id_t break_loc_id)256 bool DynamicLoaderPOSIXDYLD::EntryBreakpointHit(
257     void *baton, StoppointCallbackContext *context, user_id_t break_id,
258     user_id_t break_loc_id) {
259   assert(baton && "null baton");
260   if (!baton)
261     return false;
262 
263   Log *log = GetLog(LLDBLog::DynamicLoader);
264   DynamicLoaderPOSIXDYLD *const dyld_instance =
265       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
266   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
267             __FUNCTION__,
268             dyld_instance->m_process ? dyld_instance->m_process->GetID()
269                                      : LLDB_INVALID_PROCESS_ID);
270 
271   // Disable the breakpoint --- if a stop happens right after this, which we've
272   // seen on occasion, we don't want the breakpoint stepping thread-plan logic
273   // to show a breakpoint instruction at the disassembled entry point to the
274   // program.  Disabling it prevents it.  (One-shot is not enough - one-shot
275   // removal logic only happens after the breakpoint goes public, which wasn't
276   // happening in our scenario).
277   if (dyld_instance->m_process) {
278     BreakpointSP breakpoint_sp =
279         dyld_instance->m_process->GetTarget().GetBreakpointByID(break_id);
280     if (breakpoint_sp) {
281       LLDB_LOGF(log,
282                 "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
283                 " disabling breakpoint id %" PRIu64,
284                 __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
285       breakpoint_sp->SetEnabled(false);
286     } else {
287       LLDB_LOGF(log,
288                 "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
289                 " failed to find breakpoint for breakpoint id %" PRIu64,
290                 __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
291     }
292   } else {
293     LLDB_LOGF(log,
294               "DynamicLoaderPOSIXDYLD::%s breakpoint id %" PRIu64
295               " no Process instance!  Cannot disable breakpoint",
296               __FUNCTION__, break_id);
297   }
298 
299   dyld_instance->LoadAllCurrentModules();
300   dyld_instance->SetRendezvousBreakpoint();
301   return false; // Continue running.
302 }
303 
SetRendezvousBreakpoint()304 bool DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint() {
305   Log *log = GetLog(LLDBLog::DynamicLoader);
306 
307   // If we have a core file, we don't need any breakpoints.
308   if (IsCoreFile())
309     return false;
310 
311   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
312     LLDB_LOG(log,
313              "Rendezvous breakpoint breakpoint id {0} for pid {1}"
314              "is already set.",
315              m_dyld_bid,
316              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
317     return true;
318   }
319 
320   addr_t break_addr;
321   Target &target = m_process->GetTarget();
322   BreakpointSP dyld_break;
323   if (m_rendezvous.IsValid() && m_rendezvous.GetBreakAddress() != 0) {
324     break_addr = m_rendezvous.GetBreakAddress();
325     LLDB_LOG(log, "Setting rendezvous break address for pid {0} at {1:x}",
326              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
327              break_addr);
328     dyld_break = target.CreateBreakpoint(break_addr, true, false);
329   } else {
330     LLDB_LOG(log, "Rendezvous structure is not set up yet. "
331                   "Trying to locate rendezvous breakpoint in the interpreter "
332                   "by symbol name.");
333     // Function names from different dynamic loaders that are known to be
334     // used as rendezvous between the loader and debuggers.
335     static std::vector<std::string> DebugStateCandidates{
336         "_dl_debug_state", "rtld_db_dlactivity", "__dl_rtld_db_dlactivity",
337         "r_debug_state",   "_r_debug_state",     "_rtld_debug_state",
338     };
339 
340     ModuleSP interpreter = LoadInterpreterModule();
341     FileSpecList containingModules;
342     if (interpreter)
343       containingModules.Append(interpreter->GetFileSpec());
344     else
345       containingModules.Append(
346           m_process->GetTarget().GetExecutableModulePointer()->GetFileSpec());
347 
348     dyld_break = target.CreateBreakpoint(
349         &containingModules, /*containingSourceFiles=*/nullptr,
350         DebugStateCandidates, eFunctionNameTypeFull, eLanguageTypeC,
351         /*m_offset=*/0,
352         /*skip_prologue=*/eLazyBoolNo,
353         /*internal=*/true,
354         /*request_hardware=*/false);
355   }
356 
357   if (dyld_break->GetNumResolvedLocations() != 1) {
358     LLDB_LOG(
359         log,
360         "Rendezvous breakpoint has abnormal number of"
361         " resolved locations ({0}) in pid {1}. It's supposed to be exactly 1.",
362         dyld_break->GetNumResolvedLocations(),
363         m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
364 
365     target.RemoveBreakpointByID(dyld_break->GetID());
366     return false;
367   }
368 
369   BreakpointLocationSP location = dyld_break->GetLocationAtIndex(0);
370   LLDB_LOG(log,
371            "Successfully set rendezvous breakpoint at address {0:x} "
372            "for pid {1}",
373            location->GetLoadAddress(),
374            m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
375 
376   dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
377   dyld_break->SetBreakpointKind("shared-library-event");
378   m_dyld_bid = dyld_break->GetID();
379   return true;
380 }
381 
RendezvousBreakpointHit(void * baton,StoppointCallbackContext * context,user_id_t break_id,user_id_t break_loc_id)382 bool DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(
383     void *baton, StoppointCallbackContext *context, user_id_t break_id,
384     user_id_t break_loc_id) {
385   assert(baton && "null baton");
386   if (!baton)
387     return false;
388 
389   Log *log = GetLog(LLDBLog::DynamicLoader);
390   DynamicLoaderPOSIXDYLD *const dyld_instance =
391       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
392   LLDB_LOGF(log, "DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
393             __FUNCTION__,
394             dyld_instance->m_process ? dyld_instance->m_process->GetID()
395                                      : LLDB_INVALID_PROCESS_ID);
396 
397   dyld_instance->RefreshModules();
398 
399   // Return true to stop the target, false to just let the target run.
400   const bool stop_when_images_change = dyld_instance->GetStopWhenImagesChange();
401   LLDB_LOGF(log,
402             "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
403             " stop_when_images_change=%s",
404             __FUNCTION__,
405             dyld_instance->m_process ? dyld_instance->m_process->GetID()
406                                      : LLDB_INVALID_PROCESS_ID,
407             stop_when_images_change ? "true" : "false");
408   return stop_when_images_change;
409 }
410 
RefreshModules()411 void DynamicLoaderPOSIXDYLD::RefreshModules() {
412   if (!m_rendezvous.Resolve())
413     return;
414 
415   // The rendezvous class doesn't enumerate the main module, so track that
416   // ourselves here.
417   ModuleSP executable = GetTargetExecutable();
418   m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
419 
420   DYLDRendezvous::iterator I;
421   DYLDRendezvous::iterator E;
422 
423   ModuleList &loaded_modules = m_process->GetTarget().GetImages();
424 
425   if (m_rendezvous.ModulesDidLoad() || !m_initial_modules_added) {
426     ModuleList new_modules;
427 
428     // If this is the first time rendezvous breakpoint fires, we need
429     // to take care of adding all the initial modules reported by
430     // the loader.  This is necessary to list ld-linux.so on Linux,
431     // and all DT_NEEDED entries on *BSD.
432     if (m_initial_modules_added) {
433       I = m_rendezvous.loaded_begin();
434       E = m_rendezvous.loaded_end();
435     } else {
436       I = m_rendezvous.begin();
437       E = m_rendezvous.end();
438       m_initial_modules_added = true;
439     }
440     for (; I != E; ++I) {
441       // Don't load a duplicate copy of ld.so if we have already loaded it
442       // earlier in LoadInterpreterModule. If we instead loaded then unloaded it
443       // later, the section information for ld.so would be removed. That
444       // information is required for placing breakpoints on Arm/Thumb systems.
445       if ((m_interpreter_module.lock() != nullptr) &&
446           (I->base_addr == m_interpreter_base))
447         continue;
448 
449       ModuleSP module_sp =
450           LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
451       if (!module_sp.get())
452         continue;
453 
454       if (module_sp->GetObjectFile()->GetBaseAddress().GetLoadAddress(
455               &m_process->GetTarget()) == m_interpreter_base) {
456         ModuleSP interpreter_sp = m_interpreter_module.lock();
457         if (m_interpreter_module.lock() == nullptr) {
458           m_interpreter_module = module_sp;
459         } else if (module_sp == interpreter_sp) {
460           // Module already loaded.
461           continue;
462         }
463       }
464 
465       loaded_modules.AppendIfNeeded(module_sp);
466       new_modules.Append(module_sp);
467     }
468     m_process->GetTarget().ModulesDidLoad(new_modules);
469   }
470 
471   if (m_rendezvous.ModulesDidUnload()) {
472     ModuleList old_modules;
473 
474     E = m_rendezvous.unloaded_end();
475     for (I = m_rendezvous.unloaded_begin(); I != E; ++I) {
476       ModuleSpec module_spec{I->file_spec};
477       ModuleSP module_sp = loaded_modules.FindFirstModule(module_spec);
478 
479       if (module_sp.get()) {
480         old_modules.Append(module_sp);
481         UnloadSections(module_sp);
482       }
483     }
484     loaded_modules.Remove(old_modules);
485     m_process->GetTarget().ModulesDidUnload(old_modules, false);
486   }
487 }
488 
489 ThreadPlanSP
GetStepThroughTrampolinePlan(Thread & thread,bool stop)490 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread,
491                                                      bool stop) {
492   ThreadPlanSP thread_plan_sp;
493 
494   StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
495   const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
496   Symbol *sym = context.symbol;
497 
498   if (sym == nullptr || !sym->IsTrampoline())
499     return thread_plan_sp;
500 
501   ConstString sym_name = sym->GetMangled().GetName(Mangled::ePreferMangled);
502   if (!sym_name)
503     return thread_plan_sp;
504 
505   SymbolContextList target_symbols;
506   Target &target = thread.GetProcess()->GetTarget();
507   const ModuleList &images = target.GetImages();
508 
509   images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
510   if (!target_symbols.GetSize())
511     return thread_plan_sp;
512 
513   typedef std::vector<lldb::addr_t> AddressVector;
514   AddressVector addrs;
515   for (const SymbolContext &context : target_symbols) {
516     AddressRange range;
517     context.GetAddressRange(eSymbolContextEverything, 0, false, range);
518     lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
519     if (addr != LLDB_INVALID_ADDRESS)
520       addrs.push_back(addr);
521   }
522 
523   if (addrs.size() > 0) {
524     AddressVector::iterator start = addrs.begin();
525     AddressVector::iterator end = addrs.end();
526 
527     llvm::sort(start, end);
528     addrs.erase(std::unique(start, end), end);
529     thread_plan_sp =
530         std::make_shared<ThreadPlanRunToAddress>(thread, addrs, stop);
531   }
532 
533   return thread_plan_sp;
534 }
535 
LoadVDSO()536 void DynamicLoaderPOSIXDYLD::LoadVDSO() {
537   if (m_vdso_base == LLDB_INVALID_ADDRESS)
538     return;
539 
540   FileSpec file("[vdso]");
541 
542   MemoryRegionInfo info;
543   Status status = m_process->GetMemoryRegionInfo(m_vdso_base, info);
544   if (status.Fail()) {
545     Log *log = GetLog(LLDBLog::DynamicLoader);
546     LLDB_LOG(log, "Failed to get vdso region info: {0}", status);
547     return;
548   }
549 
550   if (ModuleSP module_sp = m_process->ReadModuleFromMemory(
551           file, m_vdso_base, info.GetRange().GetByteSize())) {
552     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_vdso_base, false);
553     m_process->GetTarget().GetImages().AppendIfNeeded(module_sp);
554   }
555 }
556 
LoadInterpreterModule()557 ModuleSP DynamicLoaderPOSIXDYLD::LoadInterpreterModule() {
558   if (m_interpreter_base == LLDB_INVALID_ADDRESS)
559     return nullptr;
560 
561   MemoryRegionInfo info;
562   Target &target = m_process->GetTarget();
563   Status status = m_process->GetMemoryRegionInfo(m_interpreter_base, info);
564   if (status.Fail() || info.GetMapped() != MemoryRegionInfo::eYes ||
565       info.GetName().IsEmpty()) {
566     Log *log = GetLog(LLDBLog::DynamicLoader);
567     LLDB_LOG(log, "Failed to get interpreter region info: {0}", status);
568     return nullptr;
569   }
570 
571   FileSpec file(info.GetName().GetCString());
572   ModuleSpec module_spec(file, target.GetArchitecture());
573 
574   if (ModuleSP module_sp = target.GetOrCreateModule(module_spec,
575                                                     true /* notify */)) {
576     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_interpreter_base,
577                          false);
578     m_interpreter_module = module_sp;
579     return module_sp;
580   }
581   return nullptr;
582 }
583 
LoadModuleAtAddress(const FileSpec & file,addr_t link_map_addr,addr_t base_addr,bool base_addr_is_offset)584 ModuleSP DynamicLoaderPOSIXDYLD::LoadModuleAtAddress(const FileSpec &file,
585                                                      addr_t link_map_addr,
586                                                      addr_t base_addr,
587                                                      bool base_addr_is_offset) {
588   if (ModuleSP module_sp = DynamicLoader::LoadModuleAtAddress(
589           file, link_map_addr, base_addr, base_addr_is_offset))
590     return module_sp;
591 
592   // This works around an dynamic linker "bug" on android <= 23, where the
593   // dynamic linker would report the application name
594   // (e.g. com.example.myapplication) instead of the main process binary
595   // (/system/bin/app_process(32)). The logic is not sound in general (it
596   // assumes base_addr is the real address, even though it actually is a load
597   // bias), but it happens to work on android because app_process has a file
598   // address of zero.
599   // This should be removed after we drop support for android-23.
600   if (m_process->GetTarget().GetArchitecture().GetTriple().isAndroid()) {
601     MemoryRegionInfo memory_info;
602     Status error = m_process->GetMemoryRegionInfo(base_addr, memory_info);
603     if (error.Success() && memory_info.GetMapped() &&
604         memory_info.GetRange().GetRangeBase() == base_addr &&
605         !(memory_info.GetName().IsEmpty())) {
606       if (ModuleSP module_sp = DynamicLoader::LoadModuleAtAddress(
607               FileSpec(memory_info.GetName().GetStringRef()), link_map_addr,
608               base_addr, base_addr_is_offset))
609         return module_sp;
610     }
611   }
612 
613   return nullptr;
614 }
615 
LoadAllCurrentModules()616 void DynamicLoaderPOSIXDYLD::LoadAllCurrentModules() {
617   DYLDRendezvous::iterator I;
618   DYLDRendezvous::iterator E;
619   ModuleList module_list;
620   Log *log = GetLog(LLDBLog::DynamicLoader);
621 
622   LoadVDSO();
623 
624   if (!m_rendezvous.Resolve()) {
625     LLDB_LOGF(log,
626               "DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD "
627               "rendezvous address",
628               __FUNCTION__);
629     return;
630   }
631 
632   // The rendezvous class doesn't enumerate the main module, so track that
633   // ourselves here.
634   ModuleSP executable = GetTargetExecutable();
635   m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
636 
637   std::vector<FileSpec> module_names;
638   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
639     module_names.push_back(I->file_spec);
640   m_process->PrefetchModuleSpecs(
641       module_names, m_process->GetTarget().GetArchitecture().GetTriple());
642 
643   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I) {
644     ModuleSP module_sp =
645         LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
646     if (module_sp.get()) {
647       LLDB_LOG(log, "LoadAllCurrentModules loading module: {0}",
648                I->file_spec.GetFilename());
649       module_list.Append(module_sp);
650     } else {
651       Log *log = GetLog(LLDBLog::DynamicLoader);
652       LLDB_LOGF(
653           log,
654           "DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
655           __FUNCTION__, I->file_spec.GetPath().c_str(), I->base_addr);
656     }
657   }
658 
659   m_process->GetTarget().ModulesDidLoad(module_list);
660   m_initial_modules_added = true;
661 }
662 
ComputeLoadOffset()663 addr_t DynamicLoaderPOSIXDYLD::ComputeLoadOffset() {
664   addr_t virt_entry;
665 
666   if (m_load_offset != LLDB_INVALID_ADDRESS)
667     return m_load_offset;
668 
669   if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
670     return LLDB_INVALID_ADDRESS;
671 
672   ModuleSP module = m_process->GetTarget().GetExecutableModule();
673   if (!module)
674     return LLDB_INVALID_ADDRESS;
675 
676   ObjectFile *exe = module->GetObjectFile();
677   if (!exe)
678     return LLDB_INVALID_ADDRESS;
679 
680   Address file_entry = exe->GetEntryPointAddress();
681 
682   if (!file_entry.IsValid())
683     return LLDB_INVALID_ADDRESS;
684 
685   m_load_offset = virt_entry - file_entry.GetFileAddress();
686   return m_load_offset;
687 }
688 
EvalSpecialModulesStatus()689 void DynamicLoaderPOSIXDYLD::EvalSpecialModulesStatus() {
690   if (std::optional<uint64_t> vdso_base =
691           m_auxv->GetAuxValue(AuxVector::AUXV_AT_SYSINFO_EHDR))
692     m_vdso_base = *vdso_base;
693 
694   if (std::optional<uint64_t> interpreter_base =
695           m_auxv->GetAuxValue(AuxVector::AUXV_AT_BASE))
696     m_interpreter_base = *interpreter_base;
697 }
698 
GetEntryPoint()699 addr_t DynamicLoaderPOSIXDYLD::GetEntryPoint() {
700   if (m_entry_point != LLDB_INVALID_ADDRESS)
701     return m_entry_point;
702 
703   if (m_auxv == nullptr)
704     return LLDB_INVALID_ADDRESS;
705 
706   std::optional<uint64_t> entry_point =
707       m_auxv->GetAuxValue(AuxVector::AUXV_AT_ENTRY);
708   if (!entry_point)
709     return LLDB_INVALID_ADDRESS;
710 
711   m_entry_point = static_cast<addr_t>(*entry_point);
712 
713   const ArchSpec &arch = m_process->GetTarget().GetArchitecture();
714 
715   // On ppc64, the entry point is actually a descriptor.  Dereference it.
716   if (arch.GetMachine() == llvm::Triple::ppc64)
717     m_entry_point = ReadUnsignedIntWithSizeInBytes(m_entry_point, 8);
718 
719   return m_entry_point;
720 }
721 
722 lldb::addr_t
GetThreadLocalData(const lldb::ModuleSP module_sp,const lldb::ThreadSP thread,lldb::addr_t tls_file_addr)723 DynamicLoaderPOSIXDYLD::GetThreadLocalData(const lldb::ModuleSP module_sp,
724                                            const lldb::ThreadSP thread,
725                                            lldb::addr_t tls_file_addr) {
726   Log *log = GetLog(LLDBLog::DynamicLoader);
727   auto it = m_loaded_modules.find(module_sp);
728   if (it == m_loaded_modules.end()) {
729     LLDB_LOGF(
730         log, "GetThreadLocalData error: module(%s) not found in loaded modules",
731         module_sp->GetObjectName().AsCString());
732     return LLDB_INVALID_ADDRESS;
733   }
734 
735   addr_t link_map = it->second;
736   if (link_map == LLDB_INVALID_ADDRESS || link_map == 0) {
737     LLDB_LOGF(log,
738               "GetThreadLocalData error: invalid link map address=0x%" PRIx64,
739               link_map);
740     return LLDB_INVALID_ADDRESS;
741   }
742 
743   const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
744   if (!metadata.valid) {
745     LLDB_LOGF(log,
746               "GetThreadLocalData error: fail to read thread info metadata");
747     return LLDB_INVALID_ADDRESS;
748   }
749 
750   LLDB_LOGF(log,
751             "GetThreadLocalData info: link_map=0x%" PRIx64
752             ", thread info metadata: "
753             "modid_offset=0x%" PRIx32 ", dtv_offset=0x%" PRIx32
754             ", tls_offset=0x%" PRIx32 ", dtv_slot_size=%" PRIx32 "\n",
755             link_map, metadata.modid_offset, metadata.dtv_offset,
756             metadata.tls_offset, metadata.dtv_slot_size);
757 
758   // Get the thread pointer.
759   addr_t tp = thread->GetThreadPointer();
760   if (tp == LLDB_INVALID_ADDRESS) {
761     LLDB_LOGF(log, "GetThreadLocalData error: fail to read thread pointer");
762     return LLDB_INVALID_ADDRESS;
763   }
764 
765   // Find the module's modid.
766   int modid_size = 4; // FIXME(spucci): This isn't right for big-endian 64-bit
767   int64_t modid = ReadUnsignedIntWithSizeInBytes(
768       link_map + metadata.modid_offset, modid_size);
769   if (modid == -1) {
770     LLDB_LOGF(log, "GetThreadLocalData error: fail to read modid");
771     return LLDB_INVALID_ADDRESS;
772   }
773 
774   // Lookup the DTV structure for this thread.
775   addr_t dtv_ptr = tp + metadata.dtv_offset;
776   addr_t dtv = ReadPointer(dtv_ptr);
777   if (dtv == LLDB_INVALID_ADDRESS) {
778     LLDB_LOGF(log, "GetThreadLocalData error: fail to read dtv");
779     return LLDB_INVALID_ADDRESS;
780   }
781 
782   // Find the TLS block for this module.
783   addr_t dtv_slot = dtv + metadata.dtv_slot_size * modid;
784   addr_t tls_block = ReadPointer(dtv_slot + metadata.tls_offset);
785 
786   LLDB_LOGF(log,
787             "DynamicLoaderPOSIXDYLD::Performed TLS lookup: "
788             "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64
789             ", modid=%" PRId64 ", tls_block=0x%" PRIx64 "\n",
790             module_sp->GetObjectName().AsCString(""), link_map, tp,
791             (int64_t)modid, tls_block);
792 
793   if (tls_block == LLDB_INVALID_ADDRESS) {
794     LLDB_LOGF(log, "GetThreadLocalData error: fail to read tls_block");
795     return LLDB_INVALID_ADDRESS;
796   } else
797     return tls_block + tls_file_addr;
798 }
799 
ResolveExecutableModule(lldb::ModuleSP & module_sp)800 void DynamicLoaderPOSIXDYLD::ResolveExecutableModule(
801     lldb::ModuleSP &module_sp) {
802   Log *log = GetLog(LLDBLog::DynamicLoader);
803 
804   if (m_process == nullptr)
805     return;
806 
807   auto &target = m_process->GetTarget();
808   const auto platform_sp = target.GetPlatform();
809 
810   ProcessInstanceInfo process_info;
811   if (!m_process->GetProcessInfo(process_info)) {
812     LLDB_LOGF(log,
813               "DynamicLoaderPOSIXDYLD::%s - failed to get process info for "
814               "pid %" PRIu64,
815               __FUNCTION__, m_process->GetID());
816     return;
817   }
818 
819   LLDB_LOGF(
820       log, "DynamicLoaderPOSIXDYLD::%s - got executable by pid %" PRIu64 ": %s",
821       __FUNCTION__, m_process->GetID(),
822       process_info.GetExecutableFile().GetPath().c_str());
823 
824   ModuleSpec module_spec(process_info.GetExecutableFile(),
825                          process_info.GetArchitecture());
826   if (module_sp && module_sp->MatchesModuleSpec(module_spec))
827     return;
828 
829   const auto executable_search_paths(Target::GetDefaultExecutableSearchPaths());
830   auto error = platform_sp->ResolveExecutable(
831       module_spec, module_sp,
832       !executable_search_paths.IsEmpty() ? &executable_search_paths : nullptr);
833   if (error.Fail()) {
834     StreamString stream;
835     module_spec.Dump(stream);
836 
837     LLDB_LOGF(log,
838               "DynamicLoaderPOSIXDYLD::%s - failed to resolve executable "
839               "with module spec \"%s\": %s",
840               __FUNCTION__, stream.GetData(), error.AsCString());
841     return;
842   }
843 
844   target.SetExecutableModule(module_sp, eLoadDependentsNo);
845 }
846 
AlwaysRelyOnEHUnwindInfo(lldb_private::SymbolContext & sym_ctx)847 bool DynamicLoaderPOSIXDYLD::AlwaysRelyOnEHUnwindInfo(
848     lldb_private::SymbolContext &sym_ctx) {
849   ModuleSP module_sp;
850   if (sym_ctx.symbol)
851     module_sp = sym_ctx.symbol->GetAddressRef().GetModule();
852   if (!module_sp && sym_ctx.function)
853     module_sp =
854         sym_ctx.function->GetAddressRange().GetBaseAddress().GetModule();
855   if (!module_sp)
856     return false;
857 
858   return module_sp->GetFileSpec().GetPath() == "[vdso]";
859 }
860 
IsCoreFile() const861 bool DynamicLoaderPOSIXDYLD::IsCoreFile() const {
862   return !m_process->IsLiveDebugSession();
863 }
864