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 
24 #include "AuxVector.h"
25 #include "DynamicLoaderPOSIXDYLD.h"
26 
27 using namespace lldb;
28 using namespace lldb_private;
29 
30 void
31 DynamicLoaderPOSIXDYLD::Initialize()
32 {
33     PluginManager::RegisterPlugin(GetPluginNameStatic(),
34                                   GetPluginDescriptionStatic(),
35                                   CreateInstance);
36 }
37 
38 void
39 DynamicLoaderPOSIXDYLD::Terminate()
40 {
41 }
42 
43 const char *
44 DynamicLoaderPOSIXDYLD::GetPluginName()
45 {
46     return "DynamicLoaderPOSIXDYLD";
47 }
48 
49 const char *
50 DynamicLoaderPOSIXDYLD::GetShortPluginName()
51 {
52     return "linux-dyld";
53 }
54 
55 const char *
56 DynamicLoaderPOSIXDYLD::GetPluginNameStatic()
57 {
58     return "dynamic-loader.linux-dyld";
59 }
60 
61 const char *
62 DynamicLoaderPOSIXDYLD::GetPluginDescriptionStatic()
63 {
64     return "Dynamic loader plug-in that watches for shared library "
65            "loads/unloads in POSIX processes.";
66 }
67 
68 void
69 DynamicLoaderPOSIXDYLD::GetPluginCommandHelp(const char *command, Stream *strm)
70 {
71 }
72 
73 uint32_t
74 DynamicLoaderPOSIXDYLD::GetPluginVersion()
75 {
76     return 1;
77 }
78 
79 DynamicLoader *
80 DynamicLoaderPOSIXDYLD::CreateInstance(Process *process, bool force)
81 {
82     bool create = force;
83     if (!create)
84     {
85         const llvm::Triple &triple_ref = process->GetTarget().GetArchitecture().GetTriple();
86         if (triple_ref.getOS() == llvm::Triple::Linux ||
87             triple_ref.getOS() == llvm::Triple::FreeBSD)
88             create = true;
89     }
90 
91     if (create)
92         return new DynamicLoaderPOSIXDYLD (process);
93     return NULL;
94 }
95 
96 DynamicLoaderPOSIXDYLD::DynamicLoaderPOSIXDYLD(Process *process)
97     : DynamicLoader(process),
98       m_rendezvous(process),
99       m_load_offset(LLDB_INVALID_ADDRESS),
100       m_entry_point(LLDB_INVALID_ADDRESS),
101       m_auxv()
102 {
103 }
104 
105 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD()
106 {
107 }
108 
109 void
110 DynamicLoaderPOSIXDYLD::DidAttach()
111 {
112     ModuleSP executable;
113     addr_t load_offset;
114 
115     m_auxv.reset(new AuxVector(m_process));
116 
117     executable = GetTargetExecutable();
118     load_offset = ComputeLoadOffset();
119 
120     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
121     {
122         ModuleList module_list;
123         module_list.Append(executable);
124         UpdateLoadedSections(executable, load_offset);
125         LoadAllCurrentModules();
126         m_process->GetTarget().ModulesDidLoad(module_list);
127     }
128 }
129 
130 void
131 DynamicLoaderPOSIXDYLD::DidLaunch()
132 {
133     ModuleSP executable;
134     addr_t load_offset;
135 
136     m_auxv.reset(new AuxVector(m_process));
137 
138     executable = GetTargetExecutable();
139     load_offset = ComputeLoadOffset();
140 
141     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
142     {
143         ModuleList module_list;
144         module_list.Append(executable);
145         UpdateLoadedSections(executable, load_offset);
146         ProbeEntry();
147         m_process->GetTarget().ModulesDidLoad(module_list);
148     }
149 }
150 
151 ModuleSP
152 DynamicLoaderPOSIXDYLD::GetTargetExecutable()
153 {
154     Target &target = m_process->GetTarget();
155     ModuleSP executable = target.GetExecutableModule();
156 
157     if (executable.get())
158     {
159         if (executable->GetFileSpec().Exists())
160         {
161             ModuleSpec module_spec (executable->GetFileSpec(), executable->GetArchitecture());
162             ModuleSP module_sp (new Module (module_spec));
163 
164             // Check if the executable has changed and set it to the target executable if they differ.
165             if (module_sp.get() && module_sp->GetUUID().IsValid() && executable->GetUUID().IsValid())
166             {
167                 if (module_sp->GetUUID() != executable->GetUUID())
168                     executable.reset();
169             }
170             else if (executable->FileHasChanged())
171             {
172                 executable.reset();
173             }
174 
175             if (!executable.get())
176             {
177                 executable = target.GetSharedModule(module_spec);
178                 if (executable.get() != target.GetExecutableModulePointer())
179                 {
180                     // Don't load dependent images since we are in dyld where we will know
181                     // and find out about all images that are loaded
182                     const bool get_dependent_images = false;
183                     target.SetExecutableModule(executable, get_dependent_images);
184                 }
185             }
186         }
187     }
188     return executable;
189 }
190 
191 Error
192 DynamicLoaderPOSIXDYLD::ExecutePluginCommand(Args &command, Stream *strm)
193 {
194     return Error();
195 }
196 
197 Log *
198 DynamicLoaderPOSIXDYLD::EnablePluginLogging(Stream *strm, Args &command)
199 {
200     return NULL;
201 }
202 
203 Error
204 DynamicLoaderPOSIXDYLD::CanLoadImage()
205 {
206     return Error();
207 }
208 
209 void
210 DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module, addr_t base_addr)
211 {
212     ObjectFile *obj_file = module->GetObjectFile();
213     SectionList *sections = obj_file->GetSectionList();
214     SectionLoadList &load_list = m_process->GetTarget().GetSectionLoadList();
215     const size_t num_sections = sections->GetSize();
216 
217     for (unsigned i = 0; i < num_sections; ++i)
218     {
219         SectionSP section_sp (sections->GetSectionAtIndex(i));
220         lldb::addr_t new_load_addr = section_sp->GetFileAddress() + base_addr;
221         lldb::addr_t old_load_addr = load_list.GetSectionLoadAddress(section_sp);
222 
223         // If the file address of the section is zero then this is not an
224         // allocatable/loadable section (property of ELF sh_addr).  Skip it.
225         if (new_load_addr == base_addr)
226             continue;
227 
228         if (old_load_addr == LLDB_INVALID_ADDRESS ||
229             old_load_addr != new_load_addr)
230             load_list.SetSectionLoadAddress(section_sp, new_load_addr);
231     }
232 }
233 
234 void
235 DynamicLoaderPOSIXDYLD::ProbeEntry()
236 {
237     Breakpoint *entry_break;
238     addr_t entry;
239 
240     if ((entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
241         return;
242 
243     entry_break = m_process->GetTarget().CreateBreakpoint(entry, true).get();
244     entry_break->SetCallback(EntryBreakpointHit, this, true);
245     entry_break->SetBreakpointKind("shared-library-event");
246 }
247 
248 // The runtime linker has run and initialized the rendezvous structure once the
249 // process has hit its entry point.  When we hit the corresponding breakpoint we
250 // interrogate the rendezvous structure to get the load addresses of all
251 // dependent modules for the process.  Similarly, we can discover the runtime
252 // linker function and setup a breakpoint to notify us of any dynamically loaded
253 // modules (via dlopen).
254 bool
255 DynamicLoaderPOSIXDYLD::EntryBreakpointHit(void *baton,
256                                            StoppointCallbackContext *context,
257                                            user_id_t break_id,
258                                            user_id_t break_loc_id)
259 {
260     DynamicLoaderPOSIXDYLD* dyld_instance;
261 
262     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
263     dyld_instance->LoadAllCurrentModules();
264     dyld_instance->SetRendezvousBreakpoint();
265     return false; // Continue running.
266 }
267 
268 void
269 DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint()
270 {
271     Breakpoint *dyld_break;
272     addr_t break_addr;
273 
274     break_addr = m_rendezvous.GetBreakAddress();
275     dyld_break = m_process->GetTarget().CreateBreakpoint(break_addr, true).get();
276     dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
277     dyld_break->SetBreakpointKind ("shared-library-event");
278 }
279 
280 bool
281 DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(void *baton,
282                                                 StoppointCallbackContext *context,
283                                                 user_id_t break_id,
284                                                 user_id_t break_loc_id)
285 {
286     DynamicLoaderPOSIXDYLD* dyld_instance;
287 
288     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
289     dyld_instance->RefreshModules();
290 
291     // Return true to stop the target, false to just let the target run.
292     return dyld_instance->GetStopWhenImagesChange();
293 }
294 
295 void
296 DynamicLoaderPOSIXDYLD::RefreshModules()
297 {
298     if (!m_rendezvous.Resolve())
299         return;
300 
301     DYLDRendezvous::iterator I;
302     DYLDRendezvous::iterator E;
303 
304     ModuleList &loaded_modules = m_process->GetTarget().GetImages();
305 
306     if (m_rendezvous.ModulesDidLoad())
307     {
308         ModuleList new_modules;
309 
310         E = m_rendezvous.loaded_end();
311         for (I = m_rendezvous.loaded_begin(); I != E; ++I)
312         {
313             FileSpec file(I->path.c_str(), true);
314             ModuleSP module_sp = LoadModuleAtAddress(file, I->base_addr);
315             if (module_sp.get())
316                 loaded_modules.AppendIfNeeded(module_sp);
317         }
318     }
319 
320     if (m_rendezvous.ModulesDidUnload())
321     {
322         ModuleList old_modules;
323 
324         E = m_rendezvous.unloaded_end();
325         for (I = m_rendezvous.unloaded_begin(); I != E; ++I)
326         {
327             FileSpec file(I->path.c_str(), true);
328             ModuleSpec module_spec (file);
329             ModuleSP module_sp =
330                 loaded_modules.FindFirstModule (module_spec);
331             if (module_sp.get())
332                 old_modules.Append(module_sp);
333         }
334         loaded_modules.Remove(old_modules);
335     }
336 }
337 
338 ThreadPlanSP
339 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread, bool stop)
340 {
341     ThreadPlanSP thread_plan_sp;
342 
343     StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
344     const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
345     Symbol *sym = context.symbol;
346 
347     if (sym == NULL || !sym->IsTrampoline())
348         return thread_plan_sp;
349 
350     const ConstString &sym_name = sym->GetMangled().GetName(Mangled::ePreferMangled);
351     if (!sym_name)
352         return thread_plan_sp;
353 
354     SymbolContextList target_symbols;
355     Target &target = thread.GetProcess()->GetTarget();
356     const ModuleList &images = target.GetImages();
357 
358     images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
359     size_t num_targets = target_symbols.GetSize();
360     if (!num_targets)
361         return thread_plan_sp;
362 
363     typedef std::vector<lldb::addr_t> AddressVector;
364     AddressVector addrs;
365     for (size_t i = 0; i < num_targets; ++i)
366     {
367         SymbolContext context;
368         AddressRange range;
369         if (target_symbols.GetContextAtIndex(i, context))
370         {
371             context.GetAddressRange(eSymbolContextEverything, 0, false, range);
372             lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
373             if (addr != LLDB_INVALID_ADDRESS)
374                 addrs.push_back(addr);
375         }
376     }
377 
378     if (addrs.size() > 0)
379     {
380         AddressVector::iterator start = addrs.begin();
381         AddressVector::iterator end = addrs.end();
382 
383         std::sort(start, end);
384         addrs.erase(std::unique(start, end), end);
385         thread_plan_sp.reset(new ThreadPlanRunToAddress(thread, addrs, stop));
386     }
387 
388     return thread_plan_sp;
389 }
390 
391 void
392 DynamicLoaderPOSIXDYLD::LoadAllCurrentModules()
393 {
394     DYLDRendezvous::iterator I;
395     DYLDRendezvous::iterator E;
396     ModuleList module_list;
397 
398     if (!m_rendezvous.Resolve())
399         return;
400 
401     for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
402     {
403         FileSpec file(I->path.c_str(), false);
404         ModuleSP module_sp = LoadModuleAtAddress(file, I->base_addr);
405         if (module_sp.get())
406             module_list.Append(module_sp);
407     }
408 
409     m_process->GetTarget().ModulesDidLoad(module_list);
410 }
411 
412 ModuleSP
413 DynamicLoaderPOSIXDYLD::LoadModuleAtAddress(const FileSpec &file, addr_t base_addr)
414 {
415     Target &target = m_process->GetTarget();
416     ModuleList &modules = target.GetImages();
417     ModuleSP module_sp;
418 
419     ModuleSpec module_spec (file, target.GetArchitecture());
420     if ((module_sp = modules.FindFirstModule (module_spec)))
421     {
422         UpdateLoadedSections(module_sp, base_addr);
423     }
424     else if ((module_sp = target.GetSharedModule(module_spec)))
425     {
426         UpdateLoadedSections(module_sp, base_addr);
427         modules.Append(module_sp);
428     }
429 
430     return module_sp;
431 }
432 
433 addr_t
434 DynamicLoaderPOSIXDYLD::ComputeLoadOffset()
435 {
436     addr_t virt_entry;
437 
438     if (m_load_offset != LLDB_INVALID_ADDRESS)
439         return m_load_offset;
440 
441     if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
442         return LLDB_INVALID_ADDRESS;
443 
444     ModuleSP module = m_process->GetTarget().GetExecutableModule();
445     ObjectFile *exe = module->GetObjectFile();
446     Address file_entry = exe->GetEntryPointAddress();
447 
448     if (!file_entry.IsValid())
449         return LLDB_INVALID_ADDRESS;
450 
451     m_load_offset = virt_entry - file_entry.GetFileAddress();
452     return m_load_offset;
453 }
454 
455 addr_t
456 DynamicLoaderPOSIXDYLD::GetEntryPoint()
457 {
458     if (m_entry_point != LLDB_INVALID_ADDRESS)
459         return m_entry_point;
460 
461     if (m_auxv.get() == NULL)
462         return LLDB_INVALID_ADDRESS;
463 
464     AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AT_ENTRY);
465 
466     if (I == m_auxv->end())
467         return LLDB_INVALID_ADDRESS;
468 
469     m_entry_point = static_cast<addr_t>(I->value);
470     return m_entry_point;
471 }
472