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 llvm::StringRef target_name = sym_name.GetStringRef();
510 // On AArch64, the trampoline name has a prefix (__AArch64ADRPThunk_ or
511 // __AArch64AbsLongThunk_) added to the function name. If we detect a
512 // trampoline with the prefix, we need to remove the prefix to find the
513 // function symbol.
514 if (target_name.consume_front("__AArch64ADRPThunk_") ||
515 target_name.consume_front("__AArch64AbsLongThunk_")) {
516 // An empty target name can happen for trampolines generated for
517 // section-referencing relocations.
518 if (!target_name.empty()) {
519 sym_name = ConstString(target_name);
520 }
521 }
522 images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
523 if (!target_symbols.GetSize())
524 return thread_plan_sp;
525
526 typedef std::vector<lldb::addr_t> AddressVector;
527 AddressVector addrs;
528 for (const SymbolContext &context : target_symbols) {
529 AddressRange range;
530 context.GetAddressRange(eSymbolContextEverything, 0, false, range);
531 lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
532 if (addr != LLDB_INVALID_ADDRESS)
533 addrs.push_back(addr);
534 }
535
536 if (addrs.size() > 0) {
537 AddressVector::iterator start = addrs.begin();
538 AddressVector::iterator end = addrs.end();
539
540 llvm::sort(start, end);
541 addrs.erase(std::unique(start, end), end);
542 thread_plan_sp =
543 std::make_shared<ThreadPlanRunToAddress>(thread, addrs, stop);
544 }
545
546 return thread_plan_sp;
547 }
548
LoadVDSO()549 void DynamicLoaderPOSIXDYLD::LoadVDSO() {
550 if (m_vdso_base == LLDB_INVALID_ADDRESS)
551 return;
552
553 FileSpec file("[vdso]");
554
555 MemoryRegionInfo info;
556 Status status = m_process->GetMemoryRegionInfo(m_vdso_base, info);
557 if (status.Fail()) {
558 Log *log = GetLog(LLDBLog::DynamicLoader);
559 LLDB_LOG(log, "Failed to get vdso region info: {0}", status);
560 return;
561 }
562
563 if (ModuleSP module_sp = m_process->ReadModuleFromMemory(
564 file, m_vdso_base, info.GetRange().GetByteSize())) {
565 UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_vdso_base, false);
566 m_process->GetTarget().GetImages().AppendIfNeeded(module_sp);
567 }
568 }
569
LoadInterpreterModule()570 ModuleSP DynamicLoaderPOSIXDYLD::LoadInterpreterModule() {
571 if (m_interpreter_base == LLDB_INVALID_ADDRESS)
572 return nullptr;
573
574 MemoryRegionInfo info;
575 Target &target = m_process->GetTarget();
576 Status status = m_process->GetMemoryRegionInfo(m_interpreter_base, info);
577 if (status.Fail() || info.GetMapped() != MemoryRegionInfo::eYes ||
578 info.GetName().IsEmpty()) {
579 Log *log = GetLog(LLDBLog::DynamicLoader);
580 LLDB_LOG(log, "Failed to get interpreter region info: {0}", status);
581 return nullptr;
582 }
583
584 FileSpec file(info.GetName().GetCString());
585 ModuleSpec module_spec(file, target.GetArchitecture());
586
587 // Don't notify that module is added here because its loading section
588 // addresses are not updated yet. We manually notify it below.
589 if (ModuleSP module_sp =
590 target.GetOrCreateModule(module_spec, /*notify=*/false)) {
591 UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_interpreter_base,
592 false);
593 // Manually notify that dynamic linker is loaded after updating load section
594 // addersses so that breakpoints can be resolved.
595 ModuleList module_list;
596 module_list.Append(module_sp);
597 target.ModulesDidLoad(module_list);
598 m_interpreter_module = module_sp;
599 return module_sp;
600 }
601 return nullptr;
602 }
603
LoadModuleAtAddress(const FileSpec & file,addr_t link_map_addr,addr_t base_addr,bool base_addr_is_offset)604 ModuleSP DynamicLoaderPOSIXDYLD::LoadModuleAtAddress(const FileSpec &file,
605 addr_t link_map_addr,
606 addr_t base_addr,
607 bool base_addr_is_offset) {
608 if (ModuleSP module_sp = DynamicLoader::LoadModuleAtAddress(
609 file, link_map_addr, base_addr, base_addr_is_offset))
610 return module_sp;
611
612 // This works around an dynamic linker "bug" on android <= 23, where the
613 // dynamic linker would report the application name
614 // (e.g. com.example.myapplication) instead of the main process binary
615 // (/system/bin/app_process(32)). The logic is not sound in general (it
616 // assumes base_addr is the real address, even though it actually is a load
617 // bias), but it happens to work on android because app_process has a file
618 // address of zero.
619 // This should be removed after we drop support for android-23.
620 if (m_process->GetTarget().GetArchitecture().GetTriple().isAndroid()) {
621 MemoryRegionInfo memory_info;
622 Status error = m_process->GetMemoryRegionInfo(base_addr, memory_info);
623 if (error.Success() && memory_info.GetMapped() &&
624 memory_info.GetRange().GetRangeBase() == base_addr &&
625 !(memory_info.GetName().IsEmpty())) {
626 if (ModuleSP module_sp = DynamicLoader::LoadModuleAtAddress(
627 FileSpec(memory_info.GetName().GetStringRef()), link_map_addr,
628 base_addr, base_addr_is_offset))
629 return module_sp;
630 }
631 }
632
633 return nullptr;
634 }
635
LoadAllCurrentModules()636 void DynamicLoaderPOSIXDYLD::LoadAllCurrentModules() {
637 DYLDRendezvous::iterator I;
638 DYLDRendezvous::iterator E;
639 ModuleList module_list;
640 Log *log = GetLog(LLDBLog::DynamicLoader);
641
642 LoadVDSO();
643
644 if (!m_rendezvous.Resolve()) {
645 LLDB_LOGF(log,
646 "DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD "
647 "rendezvous address",
648 __FUNCTION__);
649 return;
650 }
651
652 // The rendezvous class doesn't enumerate the main module, so track that
653 // ourselves here.
654 ModuleSP executable = GetTargetExecutable();
655 m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
656
657 std::vector<FileSpec> module_names;
658 for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
659 module_names.push_back(I->file_spec);
660 m_process->PrefetchModuleSpecs(
661 module_names, m_process->GetTarget().GetArchitecture().GetTriple());
662
663 for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I) {
664 ModuleSP module_sp =
665 LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
666 if (module_sp.get()) {
667 LLDB_LOG(log, "LoadAllCurrentModules loading module: {0}",
668 I->file_spec.GetFilename());
669 module_list.Append(module_sp);
670 } else {
671 Log *log = GetLog(LLDBLog::DynamicLoader);
672 LLDB_LOGF(
673 log,
674 "DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
675 __FUNCTION__, I->file_spec.GetPath().c_str(), I->base_addr);
676 }
677 }
678
679 m_process->GetTarget().ModulesDidLoad(module_list);
680 m_initial_modules_added = true;
681 }
682
ComputeLoadOffset()683 addr_t DynamicLoaderPOSIXDYLD::ComputeLoadOffset() {
684 addr_t virt_entry;
685
686 if (m_load_offset != LLDB_INVALID_ADDRESS)
687 return m_load_offset;
688
689 if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
690 return LLDB_INVALID_ADDRESS;
691
692 ModuleSP module = m_process->GetTarget().GetExecutableModule();
693 if (!module)
694 return LLDB_INVALID_ADDRESS;
695
696 ObjectFile *exe = module->GetObjectFile();
697 if (!exe)
698 return LLDB_INVALID_ADDRESS;
699
700 Address file_entry = exe->GetEntryPointAddress();
701
702 if (!file_entry.IsValid())
703 return LLDB_INVALID_ADDRESS;
704
705 m_load_offset = virt_entry - file_entry.GetFileAddress();
706 return m_load_offset;
707 }
708
EvalSpecialModulesStatus()709 void DynamicLoaderPOSIXDYLD::EvalSpecialModulesStatus() {
710 if (std::optional<uint64_t> vdso_base =
711 m_auxv->GetAuxValue(AuxVector::AUXV_AT_SYSINFO_EHDR))
712 m_vdso_base = *vdso_base;
713
714 if (std::optional<uint64_t> interpreter_base =
715 m_auxv->GetAuxValue(AuxVector::AUXV_AT_BASE))
716 m_interpreter_base = *interpreter_base;
717 }
718
GetEntryPoint()719 addr_t DynamicLoaderPOSIXDYLD::GetEntryPoint() {
720 if (m_entry_point != LLDB_INVALID_ADDRESS)
721 return m_entry_point;
722
723 if (m_auxv == nullptr)
724 return LLDB_INVALID_ADDRESS;
725
726 std::optional<uint64_t> entry_point =
727 m_auxv->GetAuxValue(AuxVector::AUXV_AT_ENTRY);
728 if (!entry_point)
729 return LLDB_INVALID_ADDRESS;
730
731 m_entry_point = static_cast<addr_t>(*entry_point);
732
733 const ArchSpec &arch = m_process->GetTarget().GetArchitecture();
734
735 // On ppc64, the entry point is actually a descriptor. Dereference it.
736 if (arch.GetMachine() == llvm::Triple::ppc64)
737 m_entry_point = ReadUnsignedIntWithSizeInBytes(m_entry_point, 8);
738
739 return m_entry_point;
740 }
741
742 lldb::addr_t
GetThreadLocalData(const lldb::ModuleSP module_sp,const lldb::ThreadSP thread,lldb::addr_t tls_file_addr)743 DynamicLoaderPOSIXDYLD::GetThreadLocalData(const lldb::ModuleSP module_sp,
744 const lldb::ThreadSP thread,
745 lldb::addr_t tls_file_addr) {
746 Log *log = GetLog(LLDBLog::DynamicLoader);
747 auto it = m_loaded_modules.find(module_sp);
748 if (it == m_loaded_modules.end()) {
749 LLDB_LOGF(
750 log, "GetThreadLocalData error: module(%s) not found in loaded modules",
751 module_sp->GetObjectName().AsCString());
752 return LLDB_INVALID_ADDRESS;
753 }
754
755 addr_t link_map = it->second;
756 if (link_map == LLDB_INVALID_ADDRESS || link_map == 0) {
757 LLDB_LOGF(log,
758 "GetThreadLocalData error: invalid link map address=0x%" PRIx64,
759 link_map);
760 return LLDB_INVALID_ADDRESS;
761 }
762
763 const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
764 if (!metadata.valid) {
765 LLDB_LOGF(log,
766 "GetThreadLocalData error: fail to read thread info metadata");
767 return LLDB_INVALID_ADDRESS;
768 }
769
770 LLDB_LOGF(log,
771 "GetThreadLocalData info: link_map=0x%" PRIx64
772 ", thread info metadata: "
773 "modid_offset=0x%" PRIx32 ", dtv_offset=0x%" PRIx32
774 ", tls_offset=0x%" PRIx32 ", dtv_slot_size=%" PRIx32 "\n",
775 link_map, metadata.modid_offset, metadata.dtv_offset,
776 metadata.tls_offset, metadata.dtv_slot_size);
777
778 // Get the thread pointer.
779 addr_t tp = thread->GetThreadPointer();
780 if (tp == LLDB_INVALID_ADDRESS) {
781 LLDB_LOGF(log, "GetThreadLocalData error: fail to read thread pointer");
782 return LLDB_INVALID_ADDRESS;
783 }
784
785 // Find the module's modid.
786 int modid_size = 4; // FIXME(spucci): This isn't right for big-endian 64-bit
787 int64_t modid = ReadUnsignedIntWithSizeInBytes(
788 link_map + metadata.modid_offset, modid_size);
789 if (modid == -1) {
790 LLDB_LOGF(log, "GetThreadLocalData error: fail to read modid");
791 return LLDB_INVALID_ADDRESS;
792 }
793
794 // Lookup the DTV structure for this thread.
795 addr_t dtv_ptr = tp + metadata.dtv_offset;
796 addr_t dtv = ReadPointer(dtv_ptr);
797 if (dtv == LLDB_INVALID_ADDRESS) {
798 LLDB_LOGF(log, "GetThreadLocalData error: fail to read dtv");
799 return LLDB_INVALID_ADDRESS;
800 }
801
802 // Find the TLS block for this module.
803 addr_t dtv_slot = dtv + metadata.dtv_slot_size * modid;
804 addr_t tls_block = ReadPointer(dtv_slot + metadata.tls_offset);
805
806 LLDB_LOGF(log,
807 "DynamicLoaderPOSIXDYLD::Performed TLS lookup: "
808 "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64
809 ", modid=%" PRId64 ", tls_block=0x%" PRIx64 "\n",
810 module_sp->GetObjectName().AsCString(""), link_map, tp,
811 (int64_t)modid, tls_block);
812
813 if (tls_block == LLDB_INVALID_ADDRESS) {
814 LLDB_LOGF(log, "GetThreadLocalData error: fail to read tls_block");
815 return LLDB_INVALID_ADDRESS;
816 } else
817 return tls_block + tls_file_addr;
818 }
819
ResolveExecutableModule(lldb::ModuleSP & module_sp)820 void DynamicLoaderPOSIXDYLD::ResolveExecutableModule(
821 lldb::ModuleSP &module_sp) {
822 Log *log = GetLog(LLDBLog::DynamicLoader);
823
824 if (m_process == nullptr)
825 return;
826
827 auto &target = m_process->GetTarget();
828 const auto platform_sp = target.GetPlatform();
829
830 ProcessInstanceInfo process_info;
831 if (!m_process->GetProcessInfo(process_info)) {
832 LLDB_LOGF(log,
833 "DynamicLoaderPOSIXDYLD::%s - failed to get process info for "
834 "pid %" PRIu64,
835 __FUNCTION__, m_process->GetID());
836 return;
837 }
838
839 LLDB_LOGF(
840 log, "DynamicLoaderPOSIXDYLD::%s - got executable by pid %" PRIu64 ": %s",
841 __FUNCTION__, m_process->GetID(),
842 process_info.GetExecutableFile().GetPath().c_str());
843
844 ModuleSpec module_spec(process_info.GetExecutableFile(),
845 process_info.GetArchitecture());
846 if (module_sp && module_sp->MatchesModuleSpec(module_spec))
847 return;
848
849 const auto executable_search_paths(Target::GetDefaultExecutableSearchPaths());
850 auto error = platform_sp->ResolveExecutable(
851 module_spec, module_sp,
852 !executable_search_paths.IsEmpty() ? &executable_search_paths : nullptr);
853 if (error.Fail()) {
854 StreamString stream;
855 module_spec.Dump(stream);
856
857 LLDB_LOGF(log,
858 "DynamicLoaderPOSIXDYLD::%s - failed to resolve executable "
859 "with module spec \"%s\": %s",
860 __FUNCTION__, stream.GetData(), error.AsCString());
861 return;
862 }
863
864 target.SetExecutableModule(module_sp, eLoadDependentsNo);
865 }
866
AlwaysRelyOnEHUnwindInfo(lldb_private::SymbolContext & sym_ctx)867 bool DynamicLoaderPOSIXDYLD::AlwaysRelyOnEHUnwindInfo(
868 lldb_private::SymbolContext &sym_ctx) {
869 ModuleSP module_sp;
870 if (sym_ctx.symbol)
871 module_sp = sym_ctx.symbol->GetAddressRef().GetModule();
872 if (!module_sp && sym_ctx.function)
873 module_sp =
874 sym_ctx.function->GetAddressRange().GetBaseAddress().GetModule();
875 if (!module_sp)
876 return false;
877
878 return module_sp->GetFileSpec().GetPath() == "[vdso]";
879 }
880
IsCoreFile() const881 bool DynamicLoaderPOSIXDYLD::IsCoreFile() const {
882 return !m_process->IsLiveDebugSession();
883 }
884