1 //===-- DynamicLoader.cpp ---------------------------------------*- 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 #include "lldb/Target/DynamicLoader.h"
11 
12 #include "lldb/Core/Module.h"
13 #include "lldb/Core/ModuleList.h" // for ModuleList
14 #include "lldb/Core/ModuleSpec.h"
15 #include "lldb/Core/PluginManager.h"
16 #include "lldb/Core/Section.h"
17 #include "lldb/Symbol/ObjectFile.h" // for ObjectFile
18 #include "lldb/Target/MemoryRegionInfo.h"
19 #include "lldb/Target/Process.h"
20 #include "lldb/Target/Target.h"
21 #include "lldb/Utility/ConstString.h"     // for ConstString
22 #include "lldb/lldb-private-interfaces.h" // for DynamicLoaderCreateInstance
23 
24 #include "llvm/ADT/StringRef.h" // for StringRef
25 
26 #include <memory> // for shared_ptr, unique_ptr
27 
28 #include <assert.h> // for assert
29 
30 using namespace lldb;
31 using namespace lldb_private;
32 
33 DynamicLoader *DynamicLoader::FindPlugin(Process *process,
34                                          const char *plugin_name) {
35   DynamicLoaderCreateInstance create_callback = nullptr;
36   if (plugin_name) {
37     ConstString const_plugin_name(plugin_name);
38     create_callback =
39         PluginManager::GetDynamicLoaderCreateCallbackForPluginName(
40             const_plugin_name);
41     if (create_callback) {
42       std::unique_ptr<DynamicLoader> instance_ap(
43           create_callback(process, true));
44       if (instance_ap)
45         return instance_ap.release();
46     }
47   } else {
48     for (uint32_t idx = 0;
49          (create_callback =
50               PluginManager::GetDynamicLoaderCreateCallbackAtIndex(idx)) !=
51          nullptr;
52          ++idx) {
53       std::unique_ptr<DynamicLoader> instance_ap(
54           create_callback(process, false));
55       if (instance_ap)
56         return instance_ap.release();
57     }
58   }
59   return nullptr;
60 }
61 
62 DynamicLoader::DynamicLoader(Process *process) : m_process(process) {}
63 
64 DynamicLoader::~DynamicLoader() = default;
65 
66 //----------------------------------------------------------------------
67 // Accessosors to the global setting as to whether to stop at image (shared
68 // library) loading/unloading.
69 //----------------------------------------------------------------------
70 
71 bool DynamicLoader::GetStopWhenImagesChange() const {
72   return m_process->GetStopOnSharedLibraryEvents();
73 }
74 
75 void DynamicLoader::SetStopWhenImagesChange(bool stop) {
76   m_process->SetStopOnSharedLibraryEvents(stop);
77 }
78 
79 ModuleSP DynamicLoader::GetTargetExecutable() {
80   Target &target = m_process->GetTarget();
81   ModuleSP executable = target.GetExecutableModule();
82 
83   if (executable) {
84     if (FileSystem::Instance().Exists(executable->GetFileSpec())) {
85       ModuleSpec module_spec(executable->GetFileSpec(),
86                              executable->GetArchitecture());
87       auto module_sp = std::make_shared<Module>(module_spec);
88 
89       // Check if the executable has changed and set it to the target
90       // executable if they differ.
91       if (module_sp && module_sp->GetUUID().IsValid() &&
92           executable->GetUUID().IsValid()) {
93         if (module_sp->GetUUID() != executable->GetUUID())
94           executable.reset();
95       } else if (executable->FileHasChanged()) {
96         executable.reset();
97       }
98 
99       if (!executable) {
100         executable = target.GetSharedModule(module_spec);
101         if (executable.get() != target.GetExecutableModulePointer()) {
102           // Don't load dependent images since we are in dyld where we will
103           // know and find out about all images that are loaded
104           target.SetExecutableModule(executable, eLoadDependentsNo);
105         }
106       }
107     }
108   }
109   return executable;
110 }
111 
112 void DynamicLoader::UpdateLoadedSections(ModuleSP module, addr_t link_map_addr,
113                                          addr_t base_addr,
114                                          bool base_addr_is_offset) {
115   UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset);
116 }
117 
118 void DynamicLoader::UpdateLoadedSectionsCommon(ModuleSP module,
119                                                addr_t base_addr,
120                                                bool base_addr_is_offset) {
121   bool changed;
122   module->SetLoadAddress(m_process->GetTarget(), base_addr, base_addr_is_offset,
123                          changed);
124 }
125 
126 void DynamicLoader::UnloadSections(const ModuleSP module) {
127   UnloadSectionsCommon(module);
128 }
129 
130 void DynamicLoader::UnloadSectionsCommon(const ModuleSP module) {
131   Target &target = m_process->GetTarget();
132   const SectionList *sections = GetSectionListFromModule(module);
133 
134   assert(sections && "SectionList missing from unloaded module.");
135 
136   const size_t num_sections = sections->GetSize();
137   for (size_t i = 0; i < num_sections; ++i) {
138     SectionSP section_sp(sections->GetSectionAtIndex(i));
139     target.SetSectionUnloaded(section_sp);
140   }
141 }
142 
143 const SectionList *
144 DynamicLoader::GetSectionListFromModule(const ModuleSP module) const {
145   SectionList *sections = nullptr;
146   if (module) {
147     ObjectFile *obj_file = module->GetObjectFile();
148     if (obj_file != nullptr) {
149       sections = obj_file->GetSectionList();
150     }
151   }
152   return sections;
153 }
154 
155 ModuleSP DynamicLoader::LoadModuleAtAddress(const FileSpec &file,
156                                             addr_t link_map_addr,
157                                             addr_t base_addr,
158                                             bool base_addr_is_offset) {
159   Target &target = m_process->GetTarget();
160   ModuleList &modules = target.GetImages();
161   ModuleSpec module_spec(file, target.GetArchitecture());
162   ModuleSP module_sp;
163 
164   if ((module_sp = modules.FindFirstModule(module_spec))) {
165     UpdateLoadedSections(module_sp, link_map_addr, base_addr,
166                          base_addr_is_offset);
167     return module_sp;
168   }
169 
170   if ((module_sp = target.GetSharedModule(module_spec))) {
171     UpdateLoadedSections(module_sp, link_map_addr, base_addr,
172                          base_addr_is_offset);
173     return module_sp;
174   }
175 
176   bool check_alternative_file_name = true;
177   if (base_addr_is_offset) {
178     // Try to fetch the load address of the file from the process as we need
179     // absolute load address to read the file out of the memory instead of a
180     // load bias.
181     bool is_loaded = false;
182     lldb::addr_t load_addr;
183     Status error = m_process->GetFileLoadAddress(file, is_loaded, load_addr);
184     if (error.Success() && is_loaded) {
185       check_alternative_file_name = false;
186       base_addr = load_addr;
187     }
188   }
189 
190   // We failed to find the module based on its name. Lets try to check if we
191   // can find a different name based on the memory region info.
192   if (check_alternative_file_name) {
193     MemoryRegionInfo memory_info;
194     Status error = m_process->GetMemoryRegionInfo(base_addr, memory_info);
195     if (error.Success() && memory_info.GetMapped() &&
196         memory_info.GetRange().GetRangeBase() == base_addr &&
197         !(memory_info.GetName().IsEmpty())) {
198       ModuleSpec new_module_spec(
199           FileSpec(memory_info.GetName().AsCString(), false),
200           target.GetArchitecture());
201 
202       if ((module_sp = modules.FindFirstModule(new_module_spec))) {
203         UpdateLoadedSections(module_sp, link_map_addr, base_addr, false);
204         return module_sp;
205       }
206 
207       if ((module_sp = target.GetSharedModule(new_module_spec))) {
208         UpdateLoadedSections(module_sp, link_map_addr, base_addr, false);
209         return module_sp;
210       }
211     }
212   }
213 
214   if ((module_sp = m_process->ReadModuleFromMemory(file, base_addr))) {
215     UpdateLoadedSections(module_sp, link_map_addr, base_addr, false);
216     target.GetImages().AppendIfNeeded(module_sp);
217   }
218 
219   return module_sp;
220 }
221 
222 int64_t DynamicLoader::ReadUnsignedIntWithSizeInBytes(addr_t addr,
223                                                       int size_in_bytes) {
224   Status error;
225   uint64_t value =
226       m_process->ReadUnsignedIntegerFromMemory(addr, size_in_bytes, 0, error);
227   if (error.Fail())
228     return -1;
229   else
230     return (int64_t)value;
231 }
232 
233 addr_t DynamicLoader::ReadPointer(addr_t addr) {
234   Status error;
235   addr_t value = m_process->ReadPointerFromMemory(addr, error);
236   if (error.Fail())
237     return LLDB_INVALID_ADDRESS;
238   else
239     return value;
240 }
241 
242 void DynamicLoader::LoadOperatingSystemPlugin(bool flush)
243 {
244     if (m_process)
245         m_process->LoadOperatingSystemPlugin(flush);
246 }
247 
248