1 //===-- NativeThreadLinux.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 "NativeThreadLinux.h"
11 
12 #include <signal.h>
13 #include <sstream>
14 
15 #include "NativeProcessLinux.h"
16 #include "NativeRegisterContextLinux.h"
17 #include "SingleStepCheck.h"
18 
19 #include "lldb/Core/Log.h"
20 #include "lldb/Core/State.h"
21 #include "lldb/Host/HostNativeThread.h"
22 #include "lldb/Host/linux/Ptrace.h"
23 #include "lldb/Utility/LLDBAssert.h"
24 #include "lldb/lldb-enumerations.h"
25 
26 #include "llvm/ADT/SmallString.h"
27 
28 #include "Plugins/Process/POSIX/CrashReason.h"
29 
30 #include <sys/syscall.h>
31 // Try to define a macro to encapsulate the tgkill syscall
32 #define tgkill(pid, tid, sig)                                                  \
33   syscall(__NR_tgkill, static_cast<::pid_t>(pid), static_cast<::pid_t>(tid),   \
34           sig)
35 
36 using namespace lldb;
37 using namespace lldb_private;
38 using namespace lldb_private::process_linux;
39 
40 namespace {
41 void LogThreadStopInfo(Log &log, const ThreadStopInfo &stop_info,
42                        const char *const header) {
43   switch (stop_info.reason) {
44   case eStopReasonNone:
45     log.Printf("%s: %s no stop reason", __FUNCTION__, header);
46     return;
47   case eStopReasonTrace:
48     log.Printf("%s: %s trace, stopping signal 0x%" PRIx32, __FUNCTION__, header,
49                stop_info.details.signal.signo);
50     return;
51   case eStopReasonBreakpoint:
52     log.Printf("%s: %s breakpoint, stopping signal 0x%" PRIx32, __FUNCTION__,
53                header, stop_info.details.signal.signo);
54     return;
55   case eStopReasonWatchpoint:
56     log.Printf("%s: %s watchpoint, stopping signal 0x%" PRIx32, __FUNCTION__,
57                header, stop_info.details.signal.signo);
58     return;
59   case eStopReasonSignal:
60     log.Printf("%s: %s signal 0x%02" PRIx32, __FUNCTION__, header,
61                stop_info.details.signal.signo);
62     return;
63   case eStopReasonException:
64     log.Printf("%s: %s exception type 0x%02" PRIx64, __FUNCTION__, header,
65                stop_info.details.exception.type);
66     return;
67   case eStopReasonExec:
68     log.Printf("%s: %s exec, stopping signal 0x%" PRIx32, __FUNCTION__, header,
69                stop_info.details.signal.signo);
70     return;
71   case eStopReasonPlanComplete:
72     log.Printf("%s: %s plan complete", __FUNCTION__, header);
73     return;
74   case eStopReasonThreadExiting:
75     log.Printf("%s: %s thread exiting", __FUNCTION__, header);
76     return;
77   case eStopReasonInstrumentation:
78     log.Printf("%s: %s instrumentation", __FUNCTION__, header);
79     return;
80   default:
81     log.Printf("%s: %s invalid stop reason %" PRIu32, __FUNCTION__, header,
82                static_cast<uint32_t>(stop_info.reason));
83   }
84 }
85 }
86 
87 NativeThreadLinux::NativeThreadLinux(NativeProcessLinux *process,
88                                      lldb::tid_t tid)
89     : NativeThreadProtocol(process, tid), m_state(StateType::eStateInvalid),
90       m_stop_info(), m_reg_context_sp(), m_stop_description() {}
91 
92 std::string NativeThreadLinux::GetName() {
93   NativeProcessProtocolSP process_sp = m_process_wp.lock();
94   if (!process_sp)
95     return "<unknown: no process>";
96 
97   // const NativeProcessLinux *const process =
98   // reinterpret_cast<NativeProcessLinux*> (process_sp->get ());
99   llvm::SmallString<32> thread_name;
100   HostNativeThread::GetName(GetID(), thread_name);
101   return thread_name.c_str();
102 }
103 
104 lldb::StateType NativeThreadLinux::GetState() { return m_state; }
105 
106 bool NativeThreadLinux::GetStopReason(ThreadStopInfo &stop_info,
107                                       std::string &description) {
108   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
109 
110   description.clear();
111 
112   switch (m_state) {
113   case eStateStopped:
114   case eStateCrashed:
115   case eStateExited:
116   case eStateSuspended:
117   case eStateUnloaded:
118     if (log)
119       LogThreadStopInfo(*log, m_stop_info, "m_stop_info in thread:");
120     stop_info = m_stop_info;
121     description = m_stop_description;
122     if (log)
123       LogThreadStopInfo(*log, stop_info, "returned stop_info:");
124 
125     return true;
126 
127   case eStateInvalid:
128   case eStateConnected:
129   case eStateAttaching:
130   case eStateLaunching:
131   case eStateRunning:
132   case eStateStepping:
133   case eStateDetached:
134     if (log) {
135       log->Printf("NativeThreadLinux::%s tid %" PRIu64
136                   " in state %s cannot answer stop reason",
137                   __FUNCTION__, GetID(), StateAsCString(m_state));
138     }
139     return false;
140   }
141   llvm_unreachable("unhandled StateType!");
142 }
143 
144 NativeRegisterContextSP NativeThreadLinux::GetRegisterContext() {
145   // Return the register context if we already created it.
146   if (m_reg_context_sp)
147     return m_reg_context_sp;
148 
149   NativeProcessProtocolSP m_process_sp = m_process_wp.lock();
150   if (!m_process_sp)
151     return NativeRegisterContextSP();
152 
153   ArchSpec target_arch;
154   if (!m_process_sp->GetArchitecture(target_arch))
155     return NativeRegisterContextSP();
156 
157   const uint32_t concrete_frame_idx = 0;
158   m_reg_context_sp.reset(
159       NativeRegisterContextLinux::CreateHostNativeRegisterContextLinux(
160           target_arch, *this, concrete_frame_idx));
161 
162   return m_reg_context_sp;
163 }
164 
165 Error NativeThreadLinux::SetWatchpoint(lldb::addr_t addr, size_t size,
166                                        uint32_t watch_flags, bool hardware) {
167   if (!hardware)
168     return Error("not implemented");
169   if (m_state == eStateLaunching)
170     return Error();
171   Error error = RemoveWatchpoint(addr);
172   if (error.Fail())
173     return error;
174   NativeRegisterContextSP reg_ctx = GetRegisterContext();
175   uint32_t wp_index = reg_ctx->SetHardwareWatchpoint(addr, size, watch_flags);
176   if (wp_index == LLDB_INVALID_INDEX32)
177     return Error("Setting hardware watchpoint failed.");
178   m_watchpoint_index_map.insert({addr, wp_index});
179   return Error();
180 }
181 
182 Error NativeThreadLinux::RemoveWatchpoint(lldb::addr_t addr) {
183   auto wp = m_watchpoint_index_map.find(addr);
184   if (wp == m_watchpoint_index_map.end())
185     return Error();
186   uint32_t wp_index = wp->second;
187   m_watchpoint_index_map.erase(wp);
188   if (GetRegisterContext()->ClearHardwareWatchpoint(wp_index))
189     return Error();
190   return Error("Clearing hardware watchpoint failed.");
191 }
192 
193 Error NativeThreadLinux::SetHardwareBreakpoint(lldb::addr_t addr, size_t size) {
194   if (m_state == eStateLaunching)
195     return Error();
196 
197   Error error = RemoveHardwareBreakpoint(addr);
198   if (error.Fail())
199     return error;
200 
201   NativeRegisterContextSP reg_ctx = GetRegisterContext();
202   uint32_t bp_index = reg_ctx->SetHardwareBreakpoint(addr, size);
203 
204   if (bp_index == LLDB_INVALID_INDEX32)
205     return Error("Setting hardware breakpoint failed.");
206 
207   m_hw_break_index_map.insert({addr, bp_index});
208   return Error();
209 }
210 
211 Error NativeThreadLinux::RemoveHardwareBreakpoint(lldb::addr_t addr) {
212   auto bp = m_hw_break_index_map.find(addr);
213   if (bp == m_hw_break_index_map.end())
214     return Error();
215 
216   uint32_t bp_index = bp->second;
217   if (GetRegisterContext()->ClearHardwareBreakpoint(bp_index)) {
218     m_hw_break_index_map.erase(bp);
219     return Error();
220   }
221 
222   return Error("Clearing hardware breakpoint failed.");
223 }
224 
225 Error NativeThreadLinux::Resume(uint32_t signo) {
226   const StateType new_state = StateType::eStateRunning;
227   MaybeLogStateChange(new_state);
228   m_state = new_state;
229 
230   m_stop_info.reason = StopReason::eStopReasonNone;
231   m_stop_description.clear();
232 
233   // If watchpoints have been set, but none on this thread,
234   // then this is a new thread. So set all existing watchpoints.
235   if (m_watchpoint_index_map.empty()) {
236     NativeProcessLinux &process = GetProcess();
237 
238     const auto &watchpoint_map = process.GetWatchpointMap();
239     GetRegisterContext()->ClearAllHardwareWatchpoints();
240     for (const auto &pair : watchpoint_map) {
241       const auto &wp = pair.second;
242       SetWatchpoint(wp.m_addr, wp.m_size, wp.m_watch_flags, wp.m_hardware);
243     }
244   }
245 
246   // Set all active hardware breakpoint on all threads.
247   if (m_hw_break_index_map.empty()) {
248     NativeProcessLinux &process = GetProcess();
249 
250     const auto &hw_breakpoint_map = process.GetHardwareBreakpointMap();
251     GetRegisterContext()->ClearAllHardwareBreakpoints();
252     for (const auto &pair : hw_breakpoint_map) {
253       const auto &bp = pair.second;
254       SetHardwareBreakpoint(bp.m_addr, bp.m_size);
255     }
256   }
257 
258   intptr_t data = 0;
259 
260   if (signo != LLDB_INVALID_SIGNAL_NUMBER)
261     data = signo;
262 
263   return NativeProcessLinux::PtraceWrapper(PTRACE_CONT, GetID(), nullptr,
264                                            reinterpret_cast<void *>(data));
265 }
266 
267 Error NativeThreadLinux::SingleStep(uint32_t signo) {
268   const StateType new_state = StateType::eStateStepping;
269   MaybeLogStateChange(new_state);
270   m_state = new_state;
271   m_stop_info.reason = StopReason::eStopReasonNone;
272 
273   if(!m_step_workaround) {
274     // If we already hava a workaround inplace, don't reset it. Otherwise, the
275     // destructor of the existing instance will run after the new instance has
276     // fetched the cpu mask, and the thread will end up with the wrong mask.
277     m_step_workaround = SingleStepWorkaround::Get(m_tid);
278   }
279 
280   intptr_t data = 0;
281   if (signo != LLDB_INVALID_SIGNAL_NUMBER)
282     data = signo;
283 
284   // If hardware single-stepping is not supported, we just do a continue. The
285   // breakpoint on the
286   // next instruction has been setup in NativeProcessLinux::Resume.
287   return NativeProcessLinux::PtraceWrapper(
288       GetProcess().SupportHardwareSingleStepping() ? PTRACE_SINGLESTEP
289                                                    : PTRACE_CONT,
290       m_tid, nullptr, reinterpret_cast<void *>(data));
291 }
292 
293 void NativeThreadLinux::SetStoppedBySignal(uint32_t signo,
294                                            const siginfo_t *info) {
295   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
296   if (log)
297     log->Printf("NativeThreadLinux::%s called with signal 0x%02" PRIx32,
298                 __FUNCTION__, signo);
299 
300   SetStopped();
301 
302   m_stop_info.reason = StopReason::eStopReasonSignal;
303   m_stop_info.details.signal.signo = signo;
304 
305   m_stop_description.clear();
306   if (info) {
307     switch (signo) {
308     case SIGSEGV:
309     case SIGBUS:
310     case SIGFPE:
311     case SIGILL:
312       // In case of MIPS64 target, SI_KERNEL is generated for invalid 64bit
313       // address.
314       const auto reason =
315           (info->si_signo == SIGBUS && info->si_code == SI_KERNEL)
316               ? CrashReason::eInvalidAddress
317               : GetCrashReason(*info);
318       m_stop_description = GetCrashReasonString(reason, *info);
319       break;
320     }
321   }
322 }
323 
324 bool NativeThreadLinux::IsStopped(int *signo) {
325   if (!StateIsStoppedState(m_state, false))
326     return false;
327 
328   // If we are stopped by a signal, return the signo.
329   if (signo && m_state == StateType::eStateStopped &&
330       m_stop_info.reason == StopReason::eStopReasonSignal) {
331     *signo = m_stop_info.details.signal.signo;
332   }
333 
334   // Regardless, we are stopped.
335   return true;
336 }
337 
338 void NativeThreadLinux::SetStopped() {
339   if (m_state == StateType::eStateStepping)
340     m_step_workaround.reset();
341 
342   const StateType new_state = StateType::eStateStopped;
343   MaybeLogStateChange(new_state);
344   m_state = new_state;
345   m_stop_description.clear();
346 }
347 
348 void NativeThreadLinux::SetStoppedByExec() {
349   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
350   if (log)
351     log->Printf("NativeThreadLinux::%s()", __FUNCTION__);
352 
353   SetStopped();
354 
355   m_stop_info.reason = StopReason::eStopReasonExec;
356   m_stop_info.details.signal.signo = SIGSTOP;
357 }
358 
359 void NativeThreadLinux::SetStoppedByBreakpoint() {
360   SetStopped();
361 
362   m_stop_info.reason = StopReason::eStopReasonBreakpoint;
363   m_stop_info.details.signal.signo = SIGTRAP;
364   m_stop_description.clear();
365 }
366 
367 void NativeThreadLinux::SetStoppedByWatchpoint(uint32_t wp_index) {
368   SetStopped();
369 
370   lldbassert(wp_index != LLDB_INVALID_INDEX32 && "wp_index cannot be invalid");
371 
372   std::ostringstream ostr;
373   ostr << GetRegisterContext()->GetWatchpointAddress(wp_index) << " ";
374   ostr << wp_index;
375 
376   /*
377    * MIPS: Last 3bits of the watchpoint address are masked by the kernel. For
378    * example:
379    * 'n' is at 0x120010d00 and 'm' is 0x120010d04. When a watchpoint is set at
380    * 'm', then
381    * watch exception is generated even when 'n' is read/written. To handle this
382    * case,
383    * find the base address of the load/store instruction and append it in the
384    * stop-info
385    * packet.
386   */
387   ostr << " " << GetRegisterContext()->GetWatchpointHitAddress(wp_index);
388 
389   m_stop_description = ostr.str();
390 
391   m_stop_info.reason = StopReason::eStopReasonWatchpoint;
392   m_stop_info.details.signal.signo = SIGTRAP;
393 }
394 
395 bool NativeThreadLinux::IsStoppedAtBreakpoint() {
396   return GetState() == StateType::eStateStopped &&
397          m_stop_info.reason == StopReason::eStopReasonBreakpoint;
398 }
399 
400 bool NativeThreadLinux::IsStoppedAtWatchpoint() {
401   return GetState() == StateType::eStateStopped &&
402          m_stop_info.reason == StopReason::eStopReasonWatchpoint;
403 }
404 
405 void NativeThreadLinux::SetStoppedByTrace() {
406   SetStopped();
407 
408   m_stop_info.reason = StopReason::eStopReasonTrace;
409   m_stop_info.details.signal.signo = SIGTRAP;
410 }
411 
412 void NativeThreadLinux::SetStoppedWithNoReason() {
413   SetStopped();
414 
415   m_stop_info.reason = StopReason::eStopReasonNone;
416   m_stop_info.details.signal.signo = 0;
417 }
418 
419 void NativeThreadLinux::SetExited() {
420   const StateType new_state = StateType::eStateExited;
421   MaybeLogStateChange(new_state);
422   m_state = new_state;
423 
424   m_stop_info.reason = StopReason::eStopReasonThreadExiting;
425 }
426 
427 Error NativeThreadLinux::RequestStop() {
428   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
429 
430   NativeProcessLinux &process = GetProcess();
431 
432   lldb::pid_t pid = process.GetID();
433   lldb::tid_t tid = GetID();
434 
435   if (log)
436     log->Printf("NativeThreadLinux::%s requesting thread stop(pid: %" PRIu64
437                 ", tid: %" PRIu64 ")",
438                 __FUNCTION__, pid, tid);
439 
440   Error err;
441   errno = 0;
442   if (::tgkill(pid, tid, SIGSTOP) != 0) {
443     err.SetErrorToErrno();
444     if (log)
445       log->Printf("NativeThreadLinux::%s tgkill(%" PRIu64 ", %" PRIu64
446                   ", SIGSTOP) failed: %s",
447                   __FUNCTION__, pid, tid, err.AsCString());
448   }
449 
450   return err;
451 }
452 
453 void NativeThreadLinux::MaybeLogStateChange(lldb::StateType new_state) {
454   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
455   // If we're not logging, we're done.
456   if (!log)
457     return;
458 
459   // If this is a state change to the same state, we're done.
460   lldb::StateType old_state = m_state;
461   if (new_state == old_state)
462     return;
463 
464   NativeProcessProtocolSP m_process_sp = m_process_wp.lock();
465   lldb::pid_t pid =
466       m_process_sp ? m_process_sp->GetID() : LLDB_INVALID_PROCESS_ID;
467 
468   // Log it.
469   log->Printf("NativeThreadLinux: thread (pid=%" PRIu64 ", tid=%" PRIu64
470               ") changing from state %s to %s",
471               pid, GetID(), StateAsCString(old_state),
472               StateAsCString(new_state));
473 }
474 
475 NativeProcessLinux &NativeThreadLinux::GetProcess() {
476   auto process_sp = std::static_pointer_cast<NativeProcessLinux>(
477       NativeThreadProtocol::GetProcess());
478   assert(process_sp);
479   return *process_sp;
480 }
481