1 //===-- DynamicLoader.cpp -------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "lldb/Target/DynamicLoader.h"
10 
11 #include "lldb/Core/Module.h"
12 #include "lldb/Core/ModuleList.h"
13 #include "lldb/Core/ModuleSpec.h"
14 #include "lldb/Core/PluginManager.h"
15 #include "lldb/Core/Section.h"
16 #include "lldb/Symbol/LocateSymbolFile.h"
17 #include "lldb/Symbol/ObjectFile.h"
18 #include "lldb/Target/MemoryRegionInfo.h"
19 #include "lldb/Target/Platform.h"
20 #include "lldb/Target/Process.h"
21 #include "lldb/Target/Target.h"
22 #include "lldb/Utility/ConstString.h"
23 #include "lldb/Utility/LLDBLog.h"
24 #include "lldb/Utility/Log.h"
25 #include "lldb/lldb-private-interfaces.h"
26 
27 #include "llvm/ADT/StringRef.h"
28 
29 #include <memory>
30 
31 #include <cassert>
32 
33 using namespace lldb;
34 using namespace lldb_private;
35 
36 DynamicLoader *DynamicLoader::FindPlugin(Process *process,
37                                          llvm::StringRef plugin_name) {
38   DynamicLoaderCreateInstance create_callback = nullptr;
39   if (!plugin_name.empty()) {
40     create_callback =
41         PluginManager::GetDynamicLoaderCreateCallbackForPluginName(plugin_name);
42     if (create_callback) {
43       std::unique_ptr<DynamicLoader> instance_up(
44           create_callback(process, true));
45       if (instance_up)
46         return instance_up.release();
47     }
48   } else {
49     for (uint32_t idx = 0;
50          (create_callback =
51               PluginManager::GetDynamicLoaderCreateCallbackAtIndex(idx)) !=
52          nullptr;
53          ++idx) {
54       std::unique_ptr<DynamicLoader> instance_up(
55           create_callback(process, false));
56       if (instance_up)
57         return instance_up.release();
58     }
59   }
60   return nullptr;
61 }
62 
63 DynamicLoader::DynamicLoader(Process *process) : m_process(process) {}
64 
65 // Accessors to the global setting as to whether to stop at image (shared
66 // library) loading/unloading.
67 
68 bool DynamicLoader::GetStopWhenImagesChange() const {
69   return m_process->GetStopOnSharedLibraryEvents();
70 }
71 
72 void DynamicLoader::SetStopWhenImagesChange(bool stop) {
73   m_process->SetStopOnSharedLibraryEvents(stop);
74 }
75 
76 ModuleSP DynamicLoader::GetTargetExecutable() {
77   Target &target = m_process->GetTarget();
78   ModuleSP executable = target.GetExecutableModule();
79 
80   if (executable) {
81     if (FileSystem::Instance().Exists(executable->GetFileSpec())) {
82       ModuleSpec module_spec(executable->GetFileSpec(),
83                              executable->GetArchitecture());
84       auto module_sp = std::make_shared<Module>(module_spec);
85 
86       // Check if the executable has changed and set it to the target
87       // executable if they differ.
88       if (module_sp && module_sp->GetUUID().IsValid() &&
89           executable->GetUUID().IsValid()) {
90         if (module_sp->GetUUID() != executable->GetUUID())
91           executable.reset();
92       } else if (executable->FileHasChanged()) {
93         executable.reset();
94       }
95 
96       if (!executable) {
97         executable = target.GetOrCreateModule(module_spec, true /* notify */);
98         if (executable.get() != target.GetExecutableModulePointer()) {
99           // Don't load dependent images since we are in dyld where we will
100           // know and find out about all images that are loaded
101           target.SetExecutableModule(executable, eLoadDependentsNo);
102         }
103       }
104     }
105   }
106   return executable;
107 }
108 
109 void DynamicLoader::UpdateLoadedSections(ModuleSP module, addr_t link_map_addr,
110                                          addr_t base_addr,
111                                          bool base_addr_is_offset) {
112   UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset);
113 }
114 
115 void DynamicLoader::UpdateLoadedSectionsCommon(ModuleSP module,
116                                                addr_t base_addr,
117                                                bool base_addr_is_offset) {
118   bool changed;
119   module->SetLoadAddress(m_process->GetTarget(), base_addr, base_addr_is_offset,
120                          changed);
121 }
122 
123 void DynamicLoader::UnloadSections(const ModuleSP module) {
124   UnloadSectionsCommon(module);
125 }
126 
127 void DynamicLoader::UnloadSectionsCommon(const ModuleSP module) {
128   Target &target = m_process->GetTarget();
129   const SectionList *sections = GetSectionListFromModule(module);
130 
131   assert(sections && "SectionList missing from unloaded module.");
132 
133   const size_t num_sections = sections->GetSize();
134   for (size_t i = 0; i < num_sections; ++i) {
135     SectionSP section_sp(sections->GetSectionAtIndex(i));
136     target.SetSectionUnloaded(section_sp);
137   }
138 }
139 
140 const SectionList *
141 DynamicLoader::GetSectionListFromModule(const ModuleSP module) const {
142   SectionList *sections = nullptr;
143   if (module) {
144     ObjectFile *obj_file = module->GetObjectFile();
145     if (obj_file != nullptr) {
146       sections = obj_file->GetSectionList();
147     }
148   }
149   return sections;
150 }
151 
152 ModuleSP DynamicLoader::FindModuleViaTarget(const FileSpec &file) {
153   Target &target = m_process->GetTarget();
154   ModuleSpec module_spec(file, target.GetArchitecture());
155 
156   if (ModuleSP module_sp = target.GetImages().FindFirstModule(module_spec))
157     return module_sp;
158 
159   if (ModuleSP module_sp = target.GetOrCreateModule(module_spec, false))
160     return module_sp;
161 
162   return nullptr;
163 }
164 
165 ModuleSP DynamicLoader::LoadModuleAtAddress(const FileSpec &file,
166                                             addr_t link_map_addr,
167                                             addr_t base_addr,
168                                             bool base_addr_is_offset) {
169   if (ModuleSP module_sp = FindModuleViaTarget(file)) {
170     UpdateLoadedSections(module_sp, link_map_addr, base_addr,
171                          base_addr_is_offset);
172     return module_sp;
173   }
174 
175   return nullptr;
176 }
177 
178 static ModuleSP ReadUnnamedMemoryModule(Process *process, addr_t addr,
179                                         llvm::StringRef name) {
180   char namebuf[80];
181   if (name.empty()) {
182     snprintf(namebuf, sizeof(namebuf), "memory-image-0x%" PRIx64, addr);
183     name = namebuf;
184   }
185   return process->ReadModuleFromMemory(FileSpec(name), addr);
186 }
187 
188 ModuleSP DynamicLoader::LoadBinaryWithUUIDAndAddress(
189     Process *process, llvm::StringRef name, UUID uuid, addr_t value,
190     bool value_is_offset, bool force_symbol_search, bool notify) {
191   ModuleSP memory_module_sp;
192   ModuleSP module_sp;
193   PlatformSP platform_sp = process->GetTarget().GetPlatform();
194   Target &target = process->GetTarget();
195   Status error;
196   ModuleSpec module_spec;
197   module_spec.GetUUID() = uuid;
198 
199   if (!uuid.IsValid() && !value_is_offset) {
200     memory_module_sp = ReadUnnamedMemoryModule(process, value, name);
201 
202     if (memory_module_sp)
203       uuid = memory_module_sp->GetUUID();
204   }
205 
206   if (uuid.IsValid()) {
207     ModuleSpec module_spec;
208     module_spec.GetUUID() = uuid;
209 
210     if (!module_sp)
211       module_sp = target.GetOrCreateModule(module_spec, false, &error);
212 
213     // If we haven't found a binary, or we don't have a SymbolFile, see
214     // if there is an external search tool that can find it.
215     if (force_symbol_search &&
216         (!module_sp || !module_sp->GetSymbolFileFileSpec())) {
217       Symbols::DownloadObjectAndSymbolFile(module_spec, error, true);
218       if (FileSystem::Instance().Exists(module_spec.GetFileSpec())) {
219         module_sp = std::make_shared<Module>(module_spec);
220       }
221     }
222   }
223 
224   // If we couldn't find the binary anywhere else, as a last resort,
225   // read it out of memory.
226   if (!module_sp.get() && value != LLDB_INVALID_ADDRESS && !value_is_offset) {
227     if (!memory_module_sp)
228       memory_module_sp = ReadUnnamedMemoryModule(process, value, name);
229     if (memory_module_sp)
230       module_sp = memory_module_sp;
231   }
232 
233   Log *log = GetLog(LLDBLog::DynamicLoader);
234   if (module_sp.get()) {
235     // Ensure the Target has an architecture set in case
236     // we need it while processing this binary/eh_frame/debug info.
237     if (!target.GetArchitecture().IsValid())
238       target.SetArchitecture(module_sp->GetArchitecture());
239     target.GetImages().AppendIfNeeded(module_sp, false);
240 
241     bool changed = false;
242     if (module_sp->GetObjectFile()) {
243       if (value != LLDB_INVALID_ADDRESS) {
244         LLDB_LOGF(log, "Loading binary UUID %s at %s 0x%" PRIx64,
245                   uuid.GetAsString().c_str(),
246                   value_is_offset ? "offset" : "address", value);
247         module_sp->SetLoadAddress(target, value, value_is_offset, changed);
248       } else {
249         // No address/offset/slide, load the binary at file address,
250         // offset 0.
251         LLDB_LOGF(log, "Loading binary UUID %s at file address",
252                   uuid.GetAsString().c_str());
253         module_sp->SetLoadAddress(target, 0, true /* value_is_slide */,
254                                   changed);
255       }
256     } else {
257       // In-memory image, load at its true address, offset 0.
258       LLDB_LOGF(log, "Loading binary UUID %s from memory at address 0x%" PRIx64,
259                 uuid.GetAsString().c_str(), value);
260       module_sp->SetLoadAddress(target, 0, true /* value_is_slide */, changed);
261     }
262 
263     if (notify) {
264       ModuleList added_module;
265       added_module.Append(module_sp, false);
266       target.ModulesDidLoad(added_module);
267     }
268   } else {
269     LLDB_LOGF(log, "Unable to find binary with UUID %s and load it at "
270                   "%s 0x%" PRIx64,
271                   uuid.GetAsString().c_str(),
272                   value_is_offset ? "offset" : "address", value);
273   }
274 
275   return module_sp;
276 }
277 
278 int64_t DynamicLoader::ReadUnsignedIntWithSizeInBytes(addr_t addr,
279                                                       int size_in_bytes) {
280   Status error;
281   uint64_t value =
282       m_process->ReadUnsignedIntegerFromMemory(addr, size_in_bytes, 0, error);
283   if (error.Fail())
284     return -1;
285   else
286     return (int64_t)value;
287 }
288 
289 addr_t DynamicLoader::ReadPointer(addr_t addr) {
290   Status error;
291   addr_t value = m_process->ReadPointerFromMemory(addr, error);
292   if (error.Fail())
293     return LLDB_INVALID_ADDRESS;
294   else
295     return value;
296 }
297 
298 void DynamicLoader::LoadOperatingSystemPlugin(bool flush)
299 {
300     if (m_process)
301         m_process->LoadOperatingSystemPlugin(flush);
302 }
303 
304