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/Debugger.h"
12#include "lldb/Core/Module.h"
13#include "lldb/Core/ModuleList.h"
14#include "lldb/Core/ModuleSpec.h"
15#include "lldb/Core/PluginManager.h"
16#include "lldb/Core/Progress.h"
17#include "lldb/Core/Section.h"
18#include "lldb/Symbol/ObjectFile.h"
19#include "lldb/Target/MemoryRegionInfo.h"
20#include "lldb/Target/Platform.h"
21#include "lldb/Target/Process.h"
22#include "lldb/Target/Target.h"
23#include "lldb/Utility/ConstString.h"
24#include "lldb/Utility/LLDBLog.h"
25#include "lldb/Utility/Log.h"
26#include "lldb/lldb-private-interfaces.h"
27
28#include "llvm/ADT/StringRef.h"
29
30#include <memory>
31
32#include <cassert>
33
34using namespace lldb;
35using namespace lldb_private;
36
37DynamicLoader *DynamicLoader::FindPlugin(Process *process,
38 llvm::StringRef plugin_name) {
39 DynamicLoaderCreateInstance create_callback = nullptr;
40 if (!plugin_name.empty()) {
41 create_callback =
42 PluginManager::GetDynamicLoaderCreateCallbackForPluginName(name: plugin_name);
43 if (create_callback) {
44 std::unique_ptr<DynamicLoader> instance_up(
45 create_callback(process, true));
46 if (instance_up)
47 return instance_up.release();
48 }
49 } else {
50 for (uint32_t idx = 0;
51 (create_callback =
52 PluginManager::GetDynamicLoaderCreateCallbackAtIndex(idx)) !=
53 nullptr;
54 ++idx) {
55 std::unique_ptr<DynamicLoader> instance_up(
56 create_callback(process, false));
57 if (instance_up)
58 return instance_up.release();
59 }
60 }
61 return nullptr;
62}
63
64DynamicLoader::DynamicLoader(Process *process) : m_process(process) {}
65
66// Accessors to the global setting as to whether to stop at image (shared
67// library) loading/unloading.
68
69bool DynamicLoader::GetStopWhenImagesChange() const {
70 return m_process->GetStopOnSharedLibraryEvents();
71}
72
73void DynamicLoader::SetStopWhenImagesChange(bool stop) {
74 m_process->SetStopOnSharedLibraryEvents(stop);
75}
76
77ModuleSP DynamicLoader::GetTargetExecutable() {
78 Target &target = m_process->GetTarget();
79 ModuleSP executable = target.GetExecutableModule();
80
81 if (executable) {
82 if (FileSystem::Instance().Exists(file_spec: executable->GetFileSpec())) {
83 ModuleSpec module_spec(executable->GetFileSpec(),
84 executable->GetArchitecture());
85 auto module_sp = std::make_shared<Module>(args&: module_spec);
86 // If we're a coredump and we already have a main executable, we don't
87 // need to reload the module list that target already has
88 if (!m_process->IsLiveDebugSession()) {
89 return executable;
90 }
91 // Check if the executable has changed and set it to the target
92 // executable if they differ.
93 if (module_sp && module_sp->GetUUID().IsValid() &&
94 executable->GetUUID().IsValid()) {
95 if (module_sp->GetUUID() != executable->GetUUID())
96 executable.reset();
97 } else if (executable->FileHasChanged()) {
98 executable.reset();
99 }
100
101 if (!executable) {
102 executable = target.GetOrCreateModule(module_spec, notify: true /* notify */);
103 if (executable.get() != target.GetExecutableModulePointer()) {
104 // Don't load dependent images since we are in dyld where we will
105 // know and find out about all images that are loaded
106 target.SetExecutableModule(module_sp&: executable, load_dependent_files: eLoadDependentsNo);
107 }
108 }
109 }
110 }
111 return executable;
112}
113
114void DynamicLoader::UpdateLoadedSections(ModuleSP module, addr_t link_map_addr,
115 addr_t base_addr,
116 bool base_addr_is_offset) {
117 UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset);
118}
119
120void DynamicLoader::UpdateLoadedSectionsCommon(ModuleSP module,
121 addr_t base_addr,
122 bool base_addr_is_offset) {
123 bool changed;
124 module->SetLoadAddress(target&: m_process->GetTarget(), value: base_addr, value_is_offset: base_addr_is_offset,
125 changed);
126}
127
128void DynamicLoader::UnloadSections(const ModuleSP module) {
129 UnloadSectionsCommon(module);
130}
131
132void DynamicLoader::UnloadSectionsCommon(const ModuleSP module) {
133 Target &target = m_process->GetTarget();
134 const SectionList *sections = GetSectionListFromModule(module);
135
136 assert(sections && "SectionList missing from unloaded module.");
137
138 const size_t num_sections = sections->GetSize();
139 for (size_t i = 0; i < num_sections; ++i) {
140 SectionSP section_sp(sections->GetSectionAtIndex(idx: i));
141 target.SetSectionUnloaded(section_sp);
142 }
143}
144
145const SectionList *
146DynamicLoader::GetSectionListFromModule(const ModuleSP module) const {
147 SectionList *sections = nullptr;
148 if (module) {
149 ObjectFile *obj_file = module->GetObjectFile();
150 if (obj_file != nullptr) {
151 sections = obj_file->GetSectionList();
152 }
153 }
154 return sections;
155}
156
157ModuleSP DynamicLoader::FindModuleViaTarget(const FileSpec &file) {
158 Target &target = m_process->GetTarget();
159 ModuleSpec module_spec(file, target.GetArchitecture());
160 if (UUID uuid = m_process->FindModuleUUID(path: file.GetPath())) {
161 // Process may be able to augment the module_spec with UUID, e.g. ELF core.
162 module_spec.GetUUID() = uuid;
163 }
164
165 if (ModuleSP module_sp = target.GetImages().FindFirstModule(module_spec))
166 return module_sp;
167
168 if (ModuleSP module_sp = target.GetOrCreateModule(module_spec, notify: false))
169 return module_sp;
170
171 return nullptr;
172}
173
174ModuleSP DynamicLoader::LoadModuleAtAddress(const FileSpec &file,
175 addr_t link_map_addr,
176 addr_t base_addr,
177 bool base_addr_is_offset) {
178 if (ModuleSP module_sp = FindModuleViaTarget(file)) {
179 UpdateLoadedSections(module: module_sp, link_map_addr, base_addr,
180 base_addr_is_offset);
181 return module_sp;
182 }
183
184 return nullptr;
185}
186
187static ModuleSP ReadUnnamedMemoryModule(Process *process, addr_t addr,
188 llvm::StringRef name) {
189 char namebuf[80];
190 if (name.empty()) {
191 snprintf(s: namebuf, maxlen: sizeof(namebuf), format: "memory-image-0x%" PRIx64, addr);
192 name = namebuf;
193 }
194 return process->ReadModuleFromMemory(file_spec: FileSpec(name), header_addr: addr);
195}
196
197ModuleSP DynamicLoader::LoadBinaryWithUUIDAndAddress(
198 Process *process, llvm::StringRef name, UUID uuid, addr_t value,
199 bool value_is_offset, bool force_symbol_search, bool notify,
200 bool set_address_in_target, bool allow_memory_image_last_resort) {
201 ModuleSP memory_module_sp;
202 ModuleSP module_sp;
203 PlatformSP platform_sp = process->GetTarget().GetPlatform();
204 Target &target = process->GetTarget();
205 Status error;
206
207 StreamString prog_str;
208 if (!name.empty()) {
209 prog_str << name.str() << " ";
210 }
211 if (uuid.IsValid())
212 prog_str << uuid.GetAsString();
213 if (value_is_offset == 0 && value != LLDB_INVALID_ADDRESS) {
214 prog_str << "at 0x";
215 prog_str.PutHex64(uvalue: value);
216 }
217
218 if (!uuid.IsValid() && !value_is_offset) {
219 memory_module_sp = ReadUnnamedMemoryModule(process, addr: value, name);
220
221 if (memory_module_sp) {
222 uuid = memory_module_sp->GetUUID();
223 if (uuid.IsValid()) {
224 prog_str << " ";
225 prog_str << uuid.GetAsString();
226 }
227 }
228 }
229 ModuleSpec module_spec;
230 module_spec.GetUUID() = uuid;
231 FileSpec name_filespec(name);
232
233 if (uuid.IsValid()) {
234 Progress progress("Locating binary", prog_str.GetString().str());
235
236 // Has lldb already seen a module with this UUID?
237 // Or have external lookup enabled in DebugSymbols on macOS.
238 if (!module_sp)
239 error = ModuleList::GetSharedModule(module_spec, module_sp, module_search_paths_ptr: nullptr,
240 old_modules: nullptr, did_create_ptr: nullptr);
241
242 // Can lldb's symbol/executable location schemes
243 // find an executable and symbol file.
244 if (!module_sp) {
245 FileSpecList search_paths = Target::GetDefaultDebugFileSearchPaths();
246 StatisticsMap symbol_locator_map;
247 module_spec.GetSymbolFileSpec() =
248 PluginManager::LocateExecutableSymbolFile(module_spec, default_search_paths: search_paths,
249 map&: symbol_locator_map);
250 ModuleSpec objfile_module_spec =
251 PluginManager::LocateExecutableObjectFile(module_spec,
252 map&: symbol_locator_map);
253 module_spec.GetFileSpec() = objfile_module_spec.GetFileSpec();
254 if (FileSystem::Instance().Exists(file_spec: module_spec.GetFileSpec()) &&
255 FileSystem::Instance().Exists(file_spec: module_spec.GetSymbolFileSpec())) {
256 module_sp = std::make_shared<Module>(args&: module_spec);
257 }
258
259 if (module_sp) {
260 module_sp->GetSymbolLocatorStatistics().merge(map_to_merge: symbol_locator_map);
261 }
262 }
263
264 // If we haven't found a binary, or we don't have a SymbolFile, see
265 // if there is an external search tool that can find it.
266 if (!module_sp || !module_sp->GetSymbolFileFileSpec()) {
267 PluginManager::DownloadObjectAndSymbolFile(module_spec, error,
268 force_lookup: force_symbol_search);
269 if (FileSystem::Instance().Exists(file_spec: module_spec.GetFileSpec())) {
270 module_sp = std::make_shared<Module>(args&: module_spec);
271 } else if (force_symbol_search && error.AsCString(default_error_str: "") &&
272 error.AsCString(default_error_str: "")[0] != '\0') {
273 *target.GetDebugger().GetAsyncErrorStream() << error.AsCString();
274 }
275 }
276
277 // If we only found the executable, create a Module based on that.
278 if (!module_sp && FileSystem::Instance().Exists(file_spec: module_spec.GetFileSpec()))
279 module_sp = std::make_shared<Module>(args&: module_spec);
280 }
281
282 // If we couldn't find the binary anywhere else, as a last resort,
283 // read it out of memory.
284 if (allow_memory_image_last_resort && !module_sp.get() &&
285 value != LLDB_INVALID_ADDRESS && !value_is_offset) {
286 if (!memory_module_sp)
287 memory_module_sp = ReadUnnamedMemoryModule(process, addr: value, name);
288 if (memory_module_sp)
289 module_sp = memory_module_sp;
290 }
291
292 Log *log = GetLog(mask: LLDBLog::DynamicLoader);
293 if (module_sp.get()) {
294 // Ensure the Target has an architecture set in case
295 // we need it while processing this binary/eh_frame/debug info.
296 if (!target.GetArchitecture().IsValid())
297 target.SetArchitecture(arch_spec: module_sp->GetArchitecture());
298 target.GetImages().AppendIfNeeded(new_module: module_sp, notify: false);
299
300 bool changed = false;
301 if (set_address_in_target) {
302 if (module_sp->GetObjectFile()) {
303 if (value != LLDB_INVALID_ADDRESS) {
304 LLDB_LOGF(log,
305 "DynamicLoader::LoadBinaryWithUUIDAndAddress Loading "
306 "binary %s UUID %s at %s 0x%" PRIx64,
307 name.str().c_str(), uuid.GetAsString().c_str(),
308 value_is_offset ? "offset" : "address", value);
309 module_sp->SetLoadAddress(target, value, value_is_offset, changed);
310 } else {
311 // No address/offset/slide, load the binary at file address,
312 // offset 0.
313 LLDB_LOGF(log,
314 "DynamicLoader::LoadBinaryWithUUIDAndAddress Loading "
315 "binary %s UUID %s at file address",
316 name.str().c_str(), uuid.GetAsString().c_str());
317 module_sp->SetLoadAddress(target, value: 0, value_is_offset: true /* value_is_slide */,
318 changed);
319 }
320 } else {
321 // In-memory image, load at its true address, offset 0.
322 LLDB_LOGF(log,
323 "DynamicLoader::LoadBinaryWithUUIDAndAddress Loading binary "
324 "%s UUID %s from memory at address 0x%" PRIx64,
325 name.str().c_str(), uuid.GetAsString().c_str(), value);
326 module_sp->SetLoadAddress(target, value: 0, value_is_offset: true /* value_is_slide */,
327 changed);
328 }
329 }
330
331 if (notify) {
332 ModuleList added_module;
333 added_module.Append(module_sp, notify: false);
334 target.ModulesDidLoad(module_list&: added_module);
335 }
336 } else {
337 if (force_symbol_search) {
338 lldb::StreamUP s = target.GetDebugger().GetAsyncErrorStream();
339 s->Printf(format: "Unable to find file");
340 if (!name.empty())
341 s->Printf(format: " %s", name.str().c_str());
342 if (uuid.IsValid())
343 s->Printf(format: " with UUID %s", uuid.GetAsString().c_str());
344 if (value != LLDB_INVALID_ADDRESS) {
345 if (value_is_offset)
346 s->Printf(format: " with slide 0x%" PRIx64, value);
347 else
348 s->Printf(format: " at address 0x%" PRIx64, value);
349 }
350 s->Printf(format: "\n");
351 }
352 LLDB_LOGF(log,
353 "Unable to find binary %s with UUID %s and load it at "
354 "%s 0x%" PRIx64,
355 name.str().c_str(), uuid.GetAsString().c_str(),
356 value_is_offset ? "offset" : "address", value);
357 }
358
359 return module_sp;
360}
361
362int64_t DynamicLoader::ReadUnsignedIntWithSizeInBytes(addr_t addr,
363 int size_in_bytes) {
364 Status error;
365 uint64_t value =
366 m_process->ReadUnsignedIntegerFromMemory(load_addr: addr, byte_size: size_in_bytes, fail_value: 0, error);
367 if (error.Fail())
368 return -1;
369 else
370 return (int64_t)value;
371}
372
373addr_t DynamicLoader::ReadPointer(addr_t addr) {
374 Status error;
375 addr_t value = m_process->ReadPointerFromMemory(vm_addr: addr, error);
376 if (error.Fail())
377 return LLDB_INVALID_ADDRESS;
378 else
379 return value;
380}
381
382void DynamicLoader::LoadOperatingSystemPlugin(bool flush)
383{
384 if (m_process)
385 m_process->LoadOperatingSystemPlugin(flush);
386}
387

source code of lldb/source/Core/DynamicLoader.cpp