1 //===-- DynamicLoaderPOSIX.h ------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // C Includes
11 // C++ Includes
12 // Other libraries and framework includes
13 #include "lldb/Core/PluginManager.h"
14 #include "lldb/Core/Log.h"
15 #include "lldb/Core/Module.h"
16 #include "lldb/Core/ModuleSpec.h"
17 #include "lldb/Core/Section.h"
18 #include "lldb/Symbol/ObjectFile.h"
19 #include "lldb/Target/Process.h"
20 #include "lldb/Target/Target.h"
21 #include "lldb/Target/Thread.h"
22 #include "lldb/Target/ThreadPlanRunToAddress.h"
23 #include "lldb/Breakpoint/BreakpointLocation.h"
24 
25 #include "AuxVector.h"
26 #include "DynamicLoaderPOSIXDYLD.h"
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 
31 void
32 DynamicLoaderPOSIXDYLD::Initialize()
33 {
34     PluginManager::RegisterPlugin(GetPluginNameStatic(),
35                                   GetPluginDescriptionStatic(),
36                                   CreateInstance);
37 }
38 
39 void
40 DynamicLoaderPOSIXDYLD::Terminate()
41 {
42 }
43 
44 lldb_private::ConstString
45 DynamicLoaderPOSIXDYLD::GetPluginName()
46 {
47     return GetPluginNameStatic();
48 }
49 
50 lldb_private::ConstString
51 DynamicLoaderPOSIXDYLD::GetPluginNameStatic()
52 {
53     static ConstString g_name("linux-dyld");
54     return g_name;
55 }
56 
57 const char *
58 DynamicLoaderPOSIXDYLD::GetPluginDescriptionStatic()
59 {
60     return "Dynamic loader plug-in that watches for shared library "
61            "loads/unloads in POSIX processes.";
62 }
63 
64 void
65 DynamicLoaderPOSIXDYLD::GetPluginCommandHelp(const char *command, Stream *strm)
66 {
67 }
68 
69 uint32_t
70 DynamicLoaderPOSIXDYLD::GetPluginVersion()
71 {
72     return 1;
73 }
74 
75 DynamicLoader *
76 DynamicLoaderPOSIXDYLD::CreateInstance(Process *process, bool force)
77 {
78     bool create = force;
79     if (!create)
80     {
81         const llvm::Triple &triple_ref = process->GetTarget().GetArchitecture().GetTriple();
82         if (triple_ref.getOS() == llvm::Triple::Linux ||
83             triple_ref.getOS() == llvm::Triple::FreeBSD)
84             create = true;
85     }
86 
87     if (create)
88         return new DynamicLoaderPOSIXDYLD (process);
89     return NULL;
90 }
91 
92 DynamicLoaderPOSIXDYLD::DynamicLoaderPOSIXDYLD(Process *process)
93     : DynamicLoader(process),
94       m_rendezvous(process),
95       m_load_offset(LLDB_INVALID_ADDRESS),
96       m_entry_point(LLDB_INVALID_ADDRESS),
97       m_auxv(),
98       m_dyld_bid(LLDB_INVALID_BREAK_ID)
99 {
100 }
101 
102 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD()
103 {
104     if (m_dyld_bid != LLDB_INVALID_BREAK_ID)
105     {
106         m_process->GetTarget().RemoveBreakpointByID (m_dyld_bid);
107         m_dyld_bid = LLDB_INVALID_BREAK_ID;
108     }
109 }
110 
111 void
112 DynamicLoaderPOSIXDYLD::DidAttach()
113 {
114     ModuleSP executable;
115     addr_t load_offset;
116 
117     m_auxv.reset(new AuxVector(m_process));
118 
119     executable = GetTargetExecutable();
120     load_offset = ComputeLoadOffset();
121 
122     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
123     {
124         ModuleList module_list;
125         module_list.Append(executable);
126         UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset);
127         LoadAllCurrentModules();
128         m_process->GetTarget().ModulesDidLoad(module_list);
129     }
130 }
131 
132 void
133 DynamicLoaderPOSIXDYLD::DidLaunch()
134 {
135     ModuleSP executable;
136     addr_t load_offset;
137 
138     m_auxv.reset(new AuxVector(m_process));
139 
140     executable = GetTargetExecutable();
141     load_offset = ComputeLoadOffset();
142 
143     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
144     {
145         ModuleList module_list;
146         module_list.Append(executable);
147         UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset);
148         ProbeEntry();
149         m_process->GetTarget().ModulesDidLoad(module_list);
150     }
151 }
152 
153 ModuleSP
154 DynamicLoaderPOSIXDYLD::GetTargetExecutable()
155 {
156     Target &target = m_process->GetTarget();
157     ModuleSP executable = target.GetExecutableModule();
158 
159     if (executable.get())
160     {
161         if (executable->GetFileSpec().Exists())
162         {
163             ModuleSpec module_spec (executable->GetFileSpec(), executable->GetArchitecture());
164             ModuleSP module_sp (new Module (module_spec));
165 
166             // Check if the executable has changed and set it to the target executable if they differ.
167             if (module_sp.get() && module_sp->GetUUID().IsValid() && executable->GetUUID().IsValid())
168             {
169                 if (module_sp->GetUUID() != executable->GetUUID())
170                     executable.reset();
171             }
172             else if (executable->FileHasChanged())
173             {
174                 executable.reset();
175             }
176 
177             if (!executable.get())
178             {
179                 executable = target.GetSharedModule(module_spec);
180                 if (executable.get() != target.GetExecutableModulePointer())
181                 {
182                     // Don't load dependent images since we are in dyld where we will know
183                     // and find out about all images that are loaded
184                     const bool get_dependent_images = false;
185                     target.SetExecutableModule(executable, get_dependent_images);
186                 }
187             }
188         }
189     }
190     return executable;
191 }
192 
193 Error
194 DynamicLoaderPOSIXDYLD::ExecutePluginCommand(Args &command, Stream *strm)
195 {
196     return Error();
197 }
198 
199 Log *
200 DynamicLoaderPOSIXDYLD::EnablePluginLogging(Stream *strm, Args &command)
201 {
202     return NULL;
203 }
204 
205 Error
206 DynamicLoaderPOSIXDYLD::CanLoadImage()
207 {
208     return Error();
209 }
210 
211 void
212 DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module, addr_t link_map_addr, addr_t base_addr)
213 {
214     Target &target = m_process->GetTarget();
215     const SectionList *sections = GetSectionListFromModule(module);
216 
217     assert(sections && "SectionList missing from loaded module.");
218 
219     m_loaded_modules[module] = link_map_addr;
220 
221     const size_t num_sections = sections->GetSize();
222 
223     for (unsigned i = 0; i < num_sections; ++i)
224     {
225         SectionSP section_sp (sections->GetSectionAtIndex(i));
226         lldb::addr_t new_load_addr = section_sp->GetFileAddress() + base_addr;
227 
228         // If the file address of the section is zero then this is not an
229         // allocatable/loadable section (property of ELF sh_addr).  Skip it.
230         if (new_load_addr == base_addr)
231             continue;
232 
233         target.SetSectionLoadAddress(section_sp, new_load_addr);
234     }
235 }
236 
237 void
238 DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module)
239 {
240     Target &target = m_process->GetTarget();
241     const SectionList *sections = GetSectionListFromModule(module);
242 
243     assert(sections && "SectionList missing from unloaded module.");
244 
245     m_loaded_modules.erase(module);
246 
247     const size_t num_sections = sections->GetSize();
248     for (size_t i = 0; i < num_sections; ++i)
249     {
250         SectionSP section_sp (sections->GetSectionAtIndex(i));
251         target.SetSectionUnloaded(section_sp);
252     }
253 }
254 
255 void
256 DynamicLoaderPOSIXDYLD::ProbeEntry()
257 {
258     Breakpoint *entry_break;
259     addr_t entry;
260 
261     if ((entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
262         return;
263 
264     entry_break = m_process->GetTarget().CreateBreakpoint(entry, true, false).get();
265     entry_break->SetCallback(EntryBreakpointHit, this, true);
266     entry_break->SetBreakpointKind("shared-library-event");
267 }
268 
269 // The runtime linker has run and initialized the rendezvous structure once the
270 // process has hit its entry point.  When we hit the corresponding breakpoint we
271 // interrogate the rendezvous structure to get the load addresses of all
272 // dependent modules for the process.  Similarly, we can discover the runtime
273 // linker function and setup a breakpoint to notify us of any dynamically loaded
274 // modules (via dlopen).
275 bool
276 DynamicLoaderPOSIXDYLD::EntryBreakpointHit(void *baton,
277                                            StoppointCallbackContext *context,
278                                            user_id_t break_id,
279                                            user_id_t break_loc_id)
280 {
281     DynamicLoaderPOSIXDYLD* dyld_instance;
282 
283     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
284     dyld_instance->LoadAllCurrentModules();
285     dyld_instance->SetRendezvousBreakpoint();
286     return false; // Continue running.
287 }
288 
289 void
290 DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint()
291 {
292     addr_t break_addr = m_rendezvous.GetBreakAddress();
293     Target &target = m_process->GetTarget();
294 
295     if (m_dyld_bid == LLDB_INVALID_BREAK_ID)
296     {
297         Breakpoint *dyld_break = target.CreateBreakpoint (break_addr, true, false).get();
298         dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
299         dyld_break->SetBreakpointKind ("shared-library-event");
300         m_dyld_bid = dyld_break->GetID();
301     }
302 
303     // Make sure our breakpoint is at the right address.
304     assert (target.GetBreakpointByID(m_dyld_bid)->FindLocationByAddress(break_addr)->GetBreakpoint().GetID() == m_dyld_bid);
305 }
306 
307 bool
308 DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(void *baton,
309                                                 StoppointCallbackContext *context,
310                                                 user_id_t break_id,
311                                                 user_id_t break_loc_id)
312 {
313     DynamicLoaderPOSIXDYLD* dyld_instance;
314 
315     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
316     dyld_instance->RefreshModules();
317 
318     // Return true to stop the target, false to just let the target run.
319     return dyld_instance->GetStopWhenImagesChange();
320 }
321 
322 void
323 DynamicLoaderPOSIXDYLD::RefreshModules()
324 {
325     if (!m_rendezvous.Resolve())
326         return;
327 
328     DYLDRendezvous::iterator I;
329     DYLDRendezvous::iterator E;
330 
331     ModuleList &loaded_modules = m_process->GetTarget().GetImages();
332 
333     if (m_rendezvous.ModulesDidLoad())
334     {
335         ModuleList new_modules;
336 
337         E = m_rendezvous.loaded_end();
338         for (I = m_rendezvous.loaded_begin(); I != E; ++I)
339         {
340             FileSpec file(I->path.c_str(), true);
341             ModuleSP module_sp = LoadModuleAtAddress(file, I->link_addr, I->base_addr);
342             if (module_sp.get())
343             {
344                 loaded_modules.AppendIfNeeded(module_sp);
345                 new_modules.Append(module_sp);
346             }
347         }
348         m_process->GetTarget().ModulesDidLoad(new_modules);
349     }
350 
351     if (m_rendezvous.ModulesDidUnload())
352     {
353         ModuleList old_modules;
354 
355         E = m_rendezvous.unloaded_end();
356         for (I = m_rendezvous.unloaded_begin(); I != E; ++I)
357         {
358             FileSpec file(I->path.c_str(), true);
359             ModuleSpec module_spec (file);
360             ModuleSP module_sp =
361                 loaded_modules.FindFirstModule (module_spec);
362 
363             if (module_sp.get())
364             {
365                 old_modules.Append(module_sp);
366                 UnloadSections(module_sp);
367             }
368         }
369         loaded_modules.Remove(old_modules);
370         m_process->GetTarget().ModulesDidUnload(old_modules, false);
371     }
372 }
373 
374 ThreadPlanSP
375 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread, bool stop)
376 {
377     ThreadPlanSP thread_plan_sp;
378 
379     StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
380     const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
381     Symbol *sym = context.symbol;
382 
383     if (sym == NULL || !sym->IsTrampoline())
384         return thread_plan_sp;
385 
386     const ConstString &sym_name = sym->GetMangled().GetName(Mangled::ePreferMangled);
387     if (!sym_name)
388         return thread_plan_sp;
389 
390     SymbolContextList target_symbols;
391     Target &target = thread.GetProcess()->GetTarget();
392     const ModuleList &images = target.GetImages();
393 
394     images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
395     size_t num_targets = target_symbols.GetSize();
396     if (!num_targets)
397         return thread_plan_sp;
398 
399     typedef std::vector<lldb::addr_t> AddressVector;
400     AddressVector addrs;
401     for (size_t i = 0; i < num_targets; ++i)
402     {
403         SymbolContext context;
404         AddressRange range;
405         if (target_symbols.GetContextAtIndex(i, context))
406         {
407             context.GetAddressRange(eSymbolContextEverything, 0, false, range);
408             lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
409             if (addr != LLDB_INVALID_ADDRESS)
410                 addrs.push_back(addr);
411         }
412     }
413 
414     if (addrs.size() > 0)
415     {
416         AddressVector::iterator start = addrs.begin();
417         AddressVector::iterator end = addrs.end();
418 
419         std::sort(start, end);
420         addrs.erase(std::unique(start, end), end);
421         thread_plan_sp.reset(new ThreadPlanRunToAddress(thread, addrs, stop));
422     }
423 
424     return thread_plan_sp;
425 }
426 
427 void
428 DynamicLoaderPOSIXDYLD::LoadAllCurrentModules()
429 {
430     DYLDRendezvous::iterator I;
431     DYLDRendezvous::iterator E;
432     ModuleList module_list;
433 
434     if (!m_rendezvous.Resolve())
435     {
436         Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
437         if (log)
438             log->Printf("DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD rendezvous address",
439                         __FUNCTION__);
440         return;
441     }
442 
443     // The rendezvous class doesn't enumerate the main module, so track
444     // that ourselves here.
445     ModuleSP executable = GetTargetExecutable();
446     m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
447 
448 
449     for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
450     {
451         const char *module_path = I->path.c_str();
452         FileSpec file(module_path, false);
453         ModuleSP module_sp = LoadModuleAtAddress(file, I->link_addr, I->base_addr);
454         if (module_sp.get())
455         {
456             module_list.Append(module_sp);
457         }
458         else
459         {
460             Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
461             if (log)
462                 log->Printf("DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
463                             __FUNCTION__, module_path, I->base_addr);
464         }
465     }
466 
467     m_process->GetTarget().ModulesDidLoad(module_list);
468 }
469 
470 ModuleSP
471 DynamicLoaderPOSIXDYLD::LoadModuleAtAddress(const FileSpec &file, addr_t link_map_addr, addr_t base_addr)
472 {
473     Target &target = m_process->GetTarget();
474     ModuleList &modules = target.GetImages();
475     ModuleSP module_sp;
476 
477     ModuleSpec module_spec (file, target.GetArchitecture());
478     if ((module_sp = modules.FindFirstModule (module_spec)))
479     {
480         UpdateLoadedSections(module_sp, link_map_addr, base_addr);
481     }
482     else if ((module_sp = target.GetSharedModule(module_spec)))
483     {
484         UpdateLoadedSections(module_sp, link_map_addr, base_addr);
485     }
486 
487     return module_sp;
488 }
489 
490 addr_t
491 DynamicLoaderPOSIXDYLD::ComputeLoadOffset()
492 {
493     addr_t virt_entry;
494 
495     if (m_load_offset != LLDB_INVALID_ADDRESS)
496         return m_load_offset;
497 
498     if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
499         return LLDB_INVALID_ADDRESS;
500 
501     ModuleSP module = m_process->GetTarget().GetExecutableModule();
502     if (!module)
503         return LLDB_INVALID_ADDRESS;
504 
505     ObjectFile *exe = module->GetObjectFile();
506     Address file_entry = exe->GetEntryPointAddress();
507 
508     if (!file_entry.IsValid())
509         return LLDB_INVALID_ADDRESS;
510 
511     m_load_offset = virt_entry - file_entry.GetFileAddress();
512     return m_load_offset;
513 }
514 
515 addr_t
516 DynamicLoaderPOSIXDYLD::GetEntryPoint()
517 {
518     if (m_entry_point != LLDB_INVALID_ADDRESS)
519         return m_entry_point;
520 
521     if (m_auxv.get() == NULL)
522         return LLDB_INVALID_ADDRESS;
523 
524     AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AT_ENTRY);
525 
526     if (I == m_auxv->end())
527         return LLDB_INVALID_ADDRESS;
528 
529     m_entry_point = static_cast<addr_t>(I->value);
530     return m_entry_point;
531 }
532 
533 const SectionList *
534 DynamicLoaderPOSIXDYLD::GetSectionListFromModule(const ModuleSP module) const
535 {
536     SectionList *sections = nullptr;
537     if (module.get())
538     {
539         ObjectFile *obj_file = module->GetObjectFile();
540         if (obj_file)
541         {
542             sections = obj_file->GetSectionList();
543         }
544     }
545     return sections;
546 }
547 
548 static int ReadInt(Process *process, addr_t addr)
549 {
550     Error error;
551     int value = (int)process->ReadUnsignedIntegerFromMemory(addr, sizeof(uint32_t), 0, error);
552     if (error.Fail())
553         return -1;
554     else
555         return value;
556 }
557 
558 static addr_t ReadPointer(Process *process, addr_t addr)
559 {
560     Error error;
561     addr_t value = process->ReadPointerFromMemory(addr, error);
562     if (error.Fail())
563         return LLDB_INVALID_ADDRESS;
564     else
565         return value;
566 }
567 
568 lldb::addr_t
569 DynamicLoaderPOSIXDYLD::GetThreadLocalData (const lldb::ModuleSP module, const lldb::ThreadSP thread)
570 {
571     auto it = m_loaded_modules.find (module);
572     if (it == m_loaded_modules.end())
573         return LLDB_INVALID_ADDRESS;
574 
575     addr_t link_map = it->second;
576     if (link_map == LLDB_INVALID_ADDRESS)
577         return LLDB_INVALID_ADDRESS;
578 
579     const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
580     if (!metadata.valid)
581         return LLDB_INVALID_ADDRESS;
582 
583     // Get the thread pointer.
584     addr_t tp = thread->GetThreadPointer ();
585     if (tp == LLDB_INVALID_ADDRESS)
586         return LLDB_INVALID_ADDRESS;
587 
588     // Find the module's modid.
589     int modid = ReadInt (m_process, link_map + metadata.modid_offset);
590     if (modid == -1)
591         return LLDB_INVALID_ADDRESS;
592 
593     // Lookup the DTV stucture for this thread.
594     addr_t dtv_ptr = tp + metadata.dtv_offset;
595     addr_t dtv = ReadPointer (m_process, dtv_ptr);
596     if (dtv == LLDB_INVALID_ADDRESS)
597         return LLDB_INVALID_ADDRESS;
598 
599     // Find the TLS block for this module.
600     addr_t dtv_slot = dtv + metadata.dtv_slot_size*modid;
601     addr_t tls_block = ReadPointer (m_process, dtv_slot + metadata.tls_offset);
602 
603     Module *mod = module.get();
604     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
605     if (log)
606         log->Printf("DynamicLoaderPOSIXDYLD::Performed TLS lookup: "
607                     "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64 ", modid=%i, tls_block=0x%" PRIx64 "\n",
608                     mod->GetObjectName().AsCString(""), link_map, tp, modid, tls_block);
609 
610     return tls_block;
611 }
612