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