Bug Summary

File:src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/../../../llvm/lldb/source/Plugins/DynamicLoader/Hexagon-DYLD/HexagonDYLDRendezvous.cpp
Warning:line 92, column 9
Although the value stored to 'cursor' is used in the enclosing expression, the value is never actually read from 'cursor'

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name HexagonDYLDRendezvous.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/../include -I /usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/obj -I /usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -I /usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/../../../llvm/lldb/include -I /usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/../../../llvm/lldb/source -I /usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/obj/../include/lldb/Plugins -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -stack-protector 2 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/liblldbPluginDynamicLoader/../../../llvm/lldb/source/Plugins/DynamicLoader/Hexagon-DYLD/HexagonDYLDRendezvous.cpp
1//===-- HexagonDYLDRendezvous.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/Core/Module.h"
10#include "lldb/Symbol/Symbol.h"
11#include "lldb/Symbol/SymbolContext.h"
12#include "lldb/Target/Process.h"
13#include "lldb/Target/Target.h"
14#include "lldb/Utility/Log.h"
15#include "lldb/Utility/Status.h"
16
17#include "lldb/Symbol/ObjectFile.h"
18#include "lldb/Target/Process.h"
19#include "lldb/Target/Target.h"
20
21#include "HexagonDYLDRendezvous.h"
22
23using namespace lldb;
24using namespace lldb_private;
25
26/// Locates the address of the rendezvous structure. Returns the address on
27/// success and LLDB_INVALID_ADDRESS on failure.
28static addr_t ResolveRendezvousAddress(Process *process) {
29 addr_t info_location;
30 addr_t info_addr;
31 Status error;
32
33 info_location = process->GetImageInfoAddress();
34
35 if (info_location == LLDB_INVALID_ADDRESS0xffffffffffffffffULL)
36 return LLDB_INVALID_ADDRESS0xffffffffffffffffULL;
37
38 info_addr = process->ReadPointerFromMemory(info_location, error);
39 if (error.Fail())
40 return LLDB_INVALID_ADDRESS0xffffffffffffffffULL;
41
42 if (info_addr == 0)
43 return LLDB_INVALID_ADDRESS0xffffffffffffffffULL;
44
45 return info_addr;
46}
47
48HexagonDYLDRendezvous::HexagonDYLDRendezvous(Process *process)
49 : m_process(process), m_rendezvous_addr(LLDB_INVALID_ADDRESS0xffffffffffffffffULL), m_current(),
50 m_previous(), m_soentries(), m_added_soentries(), m_removed_soentries() {
51 m_thread_info.valid = false;
52
53 // Cache a copy of the executable path
54 if (m_process) {
55 Module *exe_mod = m_process->GetTarget().GetExecutableModulePointer();
56 if (exe_mod)
57 exe_mod->GetFileSpec().GetPath(m_exe_path, PATH_MAX1024);
58 }
59}
60
61bool HexagonDYLDRendezvous::Resolve() {
62 const size_t word_size = 4;
63 Rendezvous info;
64 size_t address_size;
65 size_t padding;
66 addr_t info_addr;
67 addr_t cursor;
68
69 address_size = m_process->GetAddressByteSize();
70 padding = address_size - word_size;
71
72 if (m_rendezvous_addr == LLDB_INVALID_ADDRESS0xffffffffffffffffULL)
73 cursor = info_addr = ResolveRendezvousAddress(m_process);
74 else
75 cursor = info_addr = m_rendezvous_addr;
76
77 if (cursor == LLDB_INVALID_ADDRESS0xffffffffffffffffULL)
78 return false;
79
80 if (!(cursor = ReadWord(cursor, &info.version, word_size)))
81 return false;
82
83 if (!(cursor = ReadPointer(cursor + padding, &info.map_addr)))
84 return false;
85
86 if (!(cursor = ReadPointer(cursor, &info.brk)))
87 return false;
88
89 if (!(cursor = ReadWord(cursor, &info.state, word_size)))
90 return false;
91
92 if (!(cursor = ReadPointer(cursor + padding, &info.ldbase)))
Although the value stored to 'cursor' is used in the enclosing expression, the value is never actually read from 'cursor'
93 return false;
94
95 // The rendezvous was successfully read. Update our internal state.
96 m_rendezvous_addr = info_addr;
97 m_previous = m_current;
98 m_current = info;
99
100 return UpdateSOEntries();
101}
102
103void HexagonDYLDRendezvous::SetRendezvousAddress(lldb::addr_t addr) {
104 m_rendezvous_addr = addr;
105}
106
107bool HexagonDYLDRendezvous::IsValid() {
108 return m_rendezvous_addr != LLDB_INVALID_ADDRESS0xffffffffffffffffULL;
109}
110
111bool HexagonDYLDRendezvous::UpdateSOEntries() {
112 SOEntry entry;
113
114 if (m_current.map_addr == 0)
115 return false;
116
117 // When the previous and current states are consistent this is the first time
118 // we have been asked to update. Just take a snapshot of the currently
119 // loaded modules.
120 if (m_previous.state == eConsistent && m_current.state == eConsistent)
121 return TakeSnapshot(m_soentries);
122
123 // If we are about to add or remove a shared object clear out the current
124 // state and take a snapshot of the currently loaded images.
125 if (m_current.state == eAdd || m_current.state == eDelete) {
126 // this is a fudge so that we can clear the assert below.
127 m_previous.state = eConsistent;
128 // We hit this assert on the 2nd run of this function after running the
129 // calc example
130 assert(m_previous.state == eConsistent)((void)0);
131 m_soentries.clear();
132 m_added_soentries.clear();
133 m_removed_soentries.clear();
134 return TakeSnapshot(m_soentries);
135 }
136 assert(m_current.state == eConsistent)((void)0);
137
138 // Otherwise check the previous state to determine what to expect and update
139 // accordingly.
140 if (m_previous.state == eAdd)
141 return UpdateSOEntriesForAddition();
142 else if (m_previous.state == eDelete)
143 return UpdateSOEntriesForDeletion();
144
145 return false;
146}
147
148bool HexagonDYLDRendezvous::UpdateSOEntriesForAddition() {
149 SOEntry entry;
150 iterator pos;
151
152 assert(m_previous.state == eAdd)((void)0);
153
154 if (m_current.map_addr == 0)
155 return false;
156
157 for (addr_t cursor = m_current.map_addr; cursor != 0; cursor = entry.next) {
158 if (!ReadSOEntryFromMemory(cursor, entry))
159 return false;
160
161 // Only add shared libraries and not the executable. On Linux this is
162 // indicated by an empty path in the entry. On FreeBSD it is the name of
163 // the executable.
164 if (entry.path.empty() || ::strcmp(entry.path.c_str(), m_exe_path) == 0)
165 continue;
166
167 pos = std::find(m_soentries.begin(), m_soentries.end(), entry);
168 if (pos == m_soentries.end()) {
169 m_soentries.push_back(entry);
170 m_added_soentries.push_back(entry);
171 }
172 }
173
174 return true;
175}
176
177bool HexagonDYLDRendezvous::UpdateSOEntriesForDeletion() {
178 SOEntryList entry_list;
179 iterator pos;
180
181 assert(m_previous.state == eDelete)((void)0);
182
183 if (!TakeSnapshot(entry_list))
184 return false;
185
186 for (iterator I = begin(); I != end(); ++I) {
187 pos = std::find(entry_list.begin(), entry_list.end(), *I);
188 if (pos == entry_list.end())
189 m_removed_soentries.push_back(*I);
190 }
191
192 m_soentries = entry_list;
193 return true;
194}
195
196bool HexagonDYLDRendezvous::TakeSnapshot(SOEntryList &entry_list) {
197 SOEntry entry;
198
199 if (m_current.map_addr == 0)
200 return false;
201
202 for (addr_t cursor = m_current.map_addr; cursor != 0; cursor = entry.next) {
203 if (!ReadSOEntryFromMemory(cursor, entry))
204 return false;
205
206 // Only add shared libraries and not the executable. On Linux this is
207 // indicated by an empty path in the entry. On FreeBSD it is the name of
208 // the executable.
209 if (entry.path.empty() || ::strcmp(entry.path.c_str(), m_exe_path) == 0)
210 continue;
211
212 entry_list.push_back(entry);
213 }
214
215 return true;
216}
217
218addr_t HexagonDYLDRendezvous::ReadWord(addr_t addr, uint64_t *dst,
219 size_t size) {
220 Status error;
221
222 *dst = m_process->ReadUnsignedIntegerFromMemory(addr, size, 0, error);
223 if (error.Fail())
224 return 0;
225
226 return addr + size;
227}
228
229addr_t HexagonDYLDRendezvous::ReadPointer(addr_t addr, addr_t *dst) {
230 Status error;
231
232 *dst = m_process->ReadPointerFromMemory(addr, error);
233 if (error.Fail())
234 return 0;
235
236 return addr + m_process->GetAddressByteSize();
237}
238
239std::string HexagonDYLDRendezvous::ReadStringFromMemory(addr_t addr) {
240 std::string str;
241 Status error;
242 size_t size;
243 char c;
244
245 if (addr == LLDB_INVALID_ADDRESS0xffffffffffffffffULL)
246 return std::string();
247
248 for (;;) {
249 size = m_process->ReadMemory(addr, &c, 1, error);
250 if (size != 1 || error.Fail())
251 return std::string();
252 if (c == 0)
253 break;
254 else {
255 str.push_back(c);
256 addr++;
257 }
258 }
259
260 return str;
261}
262
263bool HexagonDYLDRendezvous::ReadSOEntryFromMemory(lldb::addr_t addr,
264 SOEntry &entry) {
265 entry.clear();
266 entry.link_addr = addr;
267
268 if (!(addr = ReadPointer(addr, &entry.base_addr)))
269 return false;
270
271 if (!(addr = ReadPointer(addr, &entry.path_addr)))
272 return false;
273
274 if (!(addr = ReadPointer(addr, &entry.dyn_addr)))
275 return false;
276
277 if (!(addr = ReadPointer(addr, &entry.next)))
278 return false;
279
280 if (!(addr = ReadPointer(addr, &entry.prev)))
281 return false;
282
283 entry.path = ReadStringFromMemory(entry.path_addr);
284
285 return true;
286}
287
288bool HexagonDYLDRendezvous::FindMetadata(const char *name, PThreadField field,
289 uint32_t &value) {
290 Target &target = m_process->GetTarget();
291
292 SymbolContextList list;
293 target.GetImages().FindSymbolsWithNameAndType(ConstString(name),
294 eSymbolTypeAny, list);
295 if (list.IsEmpty())
296 return false;
297
298 Address address = list[0].symbol->GetAddress();
299 addr_t addr = address.GetLoadAddress(&target);
300 if (addr == LLDB_INVALID_ADDRESS0xffffffffffffffffULL)
301 return false;
302
303 Status error;
304 value = (uint32_t)m_process->ReadUnsignedIntegerFromMemory(
305 addr + field * sizeof(uint32_t), sizeof(uint32_t), 0, error);
306 if (error.Fail())
307 return false;
308
309 if (field == eSize)
310 value /= 8; // convert bits to bytes
311
312 return true;
313}
314
315const HexagonDYLDRendezvous::ThreadInfo &
316HexagonDYLDRendezvous::GetThreadInfo() {
317 if (!m_thread_info.valid) {
318 bool ok = true;
319
320 ok &= FindMetadata("_thread_db_pthread_dtvp", eOffset,
321 m_thread_info.dtv_offset);
322 ok &=
323 FindMetadata("_thread_db_dtv_dtv", eSize, m_thread_info.dtv_slot_size);
324 ok &= FindMetadata("_thread_db_link_map_l_tls_modid", eOffset,
325 m_thread_info.modid_offset);
326 ok &= FindMetadata("_thread_db_dtv_t_pointer_val", eOffset,
327 m_thread_info.tls_offset);
328
329 if (ok)
330 m_thread_info.valid = true;
331 }
332
333 return m_thread_info;
334}
335
336void HexagonDYLDRendezvous::DumpToLog(Log *log) const {
337 int state = GetState();
338
339 if (!log)
340 return;
341
342 log->PutCString("HexagonDYLDRendezvous:");
343 LLDB_LOGF(log, " Address: %" PRIx64, GetRendezvousAddress())do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" Address: %" "llx", GetRendezvousAddress
()); } while (0);
344 LLDB_LOGF(log, " Version: %" PRIu64, GetVersion())do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" Version: %" "llu", GetVersion())
; } while (0);
345 LLDB_LOGF(log, " Link : %" PRIx64, GetLinkMapAddress())do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" Link : %" "llx", GetLinkMapAddress
()); } while (0);
346 LLDB_LOGF(log, " Break : %" PRIx64, GetBreakAddress())do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" Break : %" "llx", GetBreakAddress
()); } while (0);
347 LLDB_LOGF(log, " LDBase : %" PRIx64, GetLDBase())do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" LDBase : %" "llx", GetLDBase());
} while (0);
348 LLDB_LOGF(log, " State : %s",do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" State : %s", (state == eConsistent
) ? "consistent" : (state == eAdd) ? "add" : (state == eDelete
) ? "delete" : "unknown"); } while (0)
349 (state == eConsistent)do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" State : %s", (state == eConsistent
) ? "consistent" : (state == eAdd) ? "add" : (state == eDelete
) ? "delete" : "unknown"); } while (0)
350 ? "consistent"do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" State : %s", (state == eConsistent
) ? "consistent" : (state == eAdd) ? "add" : (state == eDelete
) ? "delete" : "unknown"); } while (0)
351 : (state == eAdd) ? "add"do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" State : %s", (state == eConsistent
) ? "consistent" : (state == eAdd) ? "add" : (state == eDelete
) ? "delete" : "unknown"); } while (0)
352 : (state == eDelete) ? "delete" : "unknown")do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" State : %s", (state == eConsistent
) ? "consistent" : (state == eAdd) ? "add" : (state == eDelete
) ? "delete" : "unknown"); } while (0);
353
354 iterator I = begin();
355 iterator E = end();
356
357 if (I != E)
358 log->PutCString("HexagonDYLDRendezvous SOEntries:");
359
360 for (int i = 1; I != E; ++I, ++i) {
361 LLDB_LOGF(log, "\n SOEntry [%d] %s", i, I->path.c_str())do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf("\n SOEntry [%d] %s", i, I->path
.c_str()); } while (0);
362 LLDB_LOGF(log, " Base : %" PRIx64, I->base_addr)do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" Base : %" "llx", I->base_addr
); } while (0);
363 LLDB_LOGF(log, " Path : %" PRIx64, I->path_addr)do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" Path : %" "llx", I->path_addr
); } while (0);
364 LLDB_LOGF(log, " Dyn : %" PRIx64, I->dyn_addr)do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" Dyn : %" "llx", I->dyn_addr
); } while (0);
365 LLDB_LOGF(log, " Next : %" PRIx64, I->next)do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" Next : %" "llx", I->next);
} while (0);
366 LLDB_LOGF(log, " Prev : %" PRIx64, I->prev)do { ::lldb_private::Log *log_private = (log); if (log_private
) log_private->Printf(" Prev : %" "llx", I->prev);
} while (0);
367 }
368}