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//===-- NativeThreadLinux.cpp ---------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "NativeThreadLinux.h"
#include <signal.h>
#include <sstream>
#include "NativeProcessLinux.h"
#include "NativeRegisterContextLinux.h"
#include "SingleStepCheck.h"
#include "lldb/Host/HostNativeThread.h"
#include "lldb/Host/linux/Ptrace.h"
#include "lldb/Host/linux/Support.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/State.h"
#include "lldb/lldb-enumerations.h"
#include "llvm/ADT/SmallString.h"
#include "Plugins/Process/POSIX/CrashReason.h"
#include <sys/syscall.h>
// Try to define a macro to encapsulate the tgkill syscall
#define tgkill(pid, tid, sig) \
syscall(__NR_tgkill, static_cast<::pid_t>(pid), static_cast<::pid_t>(tid), \
sig)
using namespace lldb;
using namespace lldb_private;
using namespace lldb_private::process_linux;
namespace {
void LogThreadStopInfo(Log &log, const ThreadStopInfo &stop_info,
const char *const header) {
switch (stop_info.reason) {
case eStopReasonNone:
log.Printf("%s: %s no stop reason", __FUNCTION__, header);
return;
case eStopReasonTrace:
log.Printf("%s: %s trace, stopping signal 0x%" PRIx32, __FUNCTION__, header,
stop_info.details.signal.signo);
return;
case eStopReasonBreakpoint:
log.Printf("%s: %s breakpoint, stopping signal 0x%" PRIx32, __FUNCTION__,
header, stop_info.details.signal.signo);
return;
case eStopReasonWatchpoint:
log.Printf("%s: %s watchpoint, stopping signal 0x%" PRIx32, __FUNCTION__,
header, stop_info.details.signal.signo);
return;
case eStopReasonSignal:
log.Printf("%s: %s signal 0x%02" PRIx32, __FUNCTION__, header,
stop_info.details.signal.signo);
return;
case eStopReasonException:
log.Printf("%s: %s exception type 0x%02" PRIx64, __FUNCTION__, header,
stop_info.details.exception.type);
return;
case eStopReasonExec:
log.Printf("%s: %s exec, stopping signal 0x%" PRIx32, __FUNCTION__, header,
stop_info.details.signal.signo);
return;
case eStopReasonPlanComplete:
log.Printf("%s: %s plan complete", __FUNCTION__, header);
return;
case eStopReasonThreadExiting:
log.Printf("%s: %s thread exiting", __FUNCTION__, header);
return;
case eStopReasonInstrumentation:
log.Printf("%s: %s instrumentation", __FUNCTION__, header);
return;
default:
log.Printf("%s: %s invalid stop reason %" PRIu32, __FUNCTION__, header,
static_cast<uint32_t>(stop_info.reason));
}
}
}
NativeThreadLinux::NativeThreadLinux(NativeProcessLinux &process,
lldb::tid_t tid)
: NativeThreadProtocol(process, tid), m_state(StateType::eStateInvalid),
m_stop_info(),
m_reg_context_up(
NativeRegisterContextLinux::CreateHostNativeRegisterContextLinux(
process.GetArchitecture(), *this)),
m_stop_description() {}
std::string NativeThreadLinux::GetName() {
NativeProcessLinux &process = GetProcess();
auto BufferOrError = getProcFile(process.GetID(), GetID(), "comm");
if (!BufferOrError)
return "";
return std::string(BufferOrError.get()->getBuffer().rtrim('\n'));
}
lldb::StateType NativeThreadLinux::GetState() { return m_state; }
bool NativeThreadLinux::GetStopReason(ThreadStopInfo &stop_info,
std::string &description) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
description.clear();
switch (m_state) {
case eStateStopped:
case eStateCrashed:
case eStateExited:
case eStateSuspended:
case eStateUnloaded:
if (log)
LogThreadStopInfo(*log, m_stop_info, "m_stop_info in thread:");
stop_info = m_stop_info;
description = m_stop_description;
if (log)
LogThreadStopInfo(*log, stop_info, "returned stop_info:");
return true;
case eStateInvalid:
case eStateConnected:
case eStateAttaching:
case eStateLaunching:
case eStateRunning:
case eStateStepping:
case eStateDetached:
if (log) {
LLDB_LOGF(log,
"NativeThreadLinux::%s tid %" PRIu64
" in state %s cannot answer stop reason",
__FUNCTION__, GetID(), StateAsCString(m_state));
}
return false;
}
llvm_unreachable("unhandled StateType!");
}
Status NativeThreadLinux::SetWatchpoint(lldb::addr_t addr, size_t size,
uint32_t watch_flags, bool hardware) {
if (!hardware)
return Status("not implemented");
if (m_state == eStateLaunching)
return Status();
Status error = RemoveWatchpoint(addr);
if (error.Fail())
return error;
uint32_t wp_index =
m_reg_context_up->SetHardwareWatchpoint(addr, size, watch_flags);
if (wp_index == LLDB_INVALID_INDEX32)
return Status("Setting hardware watchpoint failed.");
m_watchpoint_index_map.insert({addr, wp_index});
return Status();
}
Status NativeThreadLinux::RemoveWatchpoint(lldb::addr_t addr) {
auto wp = m_watchpoint_index_map.find(addr);
if (wp == m_watchpoint_index_map.end())
return Status();
uint32_t wp_index = wp->second;
m_watchpoint_index_map.erase(wp);
if (m_reg_context_up->ClearHardwareWatchpoint(wp_index))
return Status();
return Status("Clearing hardware watchpoint failed.");
}
Status NativeThreadLinux::SetHardwareBreakpoint(lldb::addr_t addr,
size_t size) {
if (m_state == eStateLaunching)
return Status();
Status error = RemoveHardwareBreakpoint(addr);
if (error.Fail())
return error;
uint32_t bp_index = m_reg_context_up->SetHardwareBreakpoint(addr, size);
if (bp_index == LLDB_INVALID_INDEX32)
return Status("Setting hardware breakpoint failed.");
m_hw_break_index_map.insert({addr, bp_index});
return Status();
}
Status NativeThreadLinux::RemoveHardwareBreakpoint(lldb::addr_t addr) {
auto bp = m_hw_break_index_map.find(addr);
if (bp == m_hw_break_index_map.end())
return Status();
uint32_t bp_index = bp->second;
if (m_reg_context_up->ClearHardwareBreakpoint(bp_index)) {
m_hw_break_index_map.erase(bp);
return Status();
}
return Status("Clearing hardware breakpoint failed.");
}
Status NativeThreadLinux::Resume(uint32_t signo) {
const StateType new_state = StateType::eStateRunning;
MaybeLogStateChange(new_state);
m_state = new_state;
m_stop_info.reason = StopReason::eStopReasonNone;
m_stop_description.clear();
// If watchpoints have been set, but none on this thread, then this is a new
// thread. So set all existing watchpoints.
if (m_watchpoint_index_map.empty()) {
NativeProcessLinux &process = GetProcess();
const auto &watchpoint_map = process.GetWatchpointMap();
m_reg_context_up->ClearAllHardwareWatchpoints();
for (const auto &pair : watchpoint_map) {
const auto &wp = pair.second;
SetWatchpoint(wp.m_addr, wp.m_size, wp.m_watch_flags, wp.m_hardware);
}
}
// Set all active hardware breakpoint on all threads.
if (m_hw_break_index_map.empty()) {
NativeProcessLinux &process = GetProcess();
const auto &hw_breakpoint_map = process.GetHardwareBreakpointMap();
m_reg_context_up->ClearAllHardwareBreakpoints();
for (const auto &pair : hw_breakpoint_map) {
const auto &bp = pair.second;
SetHardwareBreakpoint(bp.m_addr, bp.m_size);
}
}
intptr_t data = 0;
if (signo != LLDB_INVALID_SIGNAL_NUMBER)
data = signo;
return NativeProcessLinux::PtraceWrapper(PTRACE_CONT, GetID(), nullptr,
reinterpret_cast<void *>(data));
}
Status NativeThreadLinux::SingleStep(uint32_t signo) {
const StateType new_state = StateType::eStateStepping;
MaybeLogStateChange(new_state);
m_state = new_state;
m_stop_info.reason = StopReason::eStopReasonNone;
if(!m_step_workaround) {
// If we already hava a workaround inplace, don't reset it. Otherwise, the
// destructor of the existing instance will run after the new instance has
// fetched the cpu mask, and the thread will end up with the wrong mask.
m_step_workaround = SingleStepWorkaround::Get(m_tid);
}
intptr_t data = 0;
if (signo != LLDB_INVALID_SIGNAL_NUMBER)
data = signo;
// If hardware single-stepping is not supported, we just do a continue. The
// breakpoint on the next instruction has been setup in
// NativeProcessLinux::Resume.
return NativeProcessLinux::PtraceWrapper(
GetProcess().SupportHardwareSingleStepping() ? PTRACE_SINGLESTEP
: PTRACE_CONT,
m_tid, nullptr, reinterpret_cast<void *>(data));
}
void NativeThreadLinux::SetStoppedBySignal(uint32_t signo,
const siginfo_t *info) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
LLDB_LOGF(log, "NativeThreadLinux::%s called with signal 0x%02" PRIx32,
__FUNCTION__, signo);
SetStopped();
m_stop_info.reason = StopReason::eStopReasonSignal;
m_stop_info.details.signal.signo = signo;
m_stop_description.clear();
if (info) {
switch (signo) {
case SIGSEGV:
case SIGBUS:
case SIGFPE:
case SIGILL:
// In case of MIPS64 target, SI_KERNEL is generated for invalid 64bit
// address.
const auto reason =
(info->si_signo == SIGBUS && info->si_code == SI_KERNEL)
? CrashReason::eInvalidAddress
: GetCrashReason(*info);
m_stop_description = GetCrashReasonString(reason, *info);
break;
}
}
}
bool NativeThreadLinux::IsStopped(int *signo) {
if (!StateIsStoppedState(m_state, false))
return false;
// If we are stopped by a signal, return the signo.
if (signo && m_state == StateType::eStateStopped &&
m_stop_info.reason == StopReason::eStopReasonSignal) {
*signo = m_stop_info.details.signal.signo;
}
// Regardless, we are stopped.
return true;
}
void NativeThreadLinux::SetStopped() {
if (m_state == StateType::eStateStepping)
m_step_workaround.reset();
// On every stop, clear any cached register data structures
GetRegisterContext().InvalidateAllRegisters();
const StateType new_state = StateType::eStateStopped;
MaybeLogStateChange(new_state);
m_state = new_state;
m_stop_description.clear();
}
void NativeThreadLinux::SetStoppedByExec() {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
LLDB_LOGF(log, "NativeThreadLinux::%s()", __FUNCTION__);
SetStopped();
m_stop_info.reason = StopReason::eStopReasonExec;
m_stop_info.details.signal.signo = SIGSTOP;
}
void NativeThreadLinux::SetStoppedByBreakpoint() {
SetStopped();
m_stop_info.reason = StopReason::eStopReasonBreakpoint;
m_stop_info.details.signal.signo = SIGTRAP;
m_stop_description.clear();
}
void NativeThreadLinux::SetStoppedByWatchpoint(uint32_t wp_index) {
SetStopped();
lldbassert(wp_index != LLDB_INVALID_INDEX32 && "wp_index cannot be invalid");
std::ostringstream ostr;
ostr << m_reg_context_up->GetWatchpointAddress(wp_index) << " ";
ostr << wp_index;
/*
* MIPS: Last 3bits of the watchpoint address are masked by the kernel. For
* example:
* 'n' is at 0x120010d00 and 'm' is 0x120010d04. When a watchpoint is set at
* 'm', then
* watch exception is generated even when 'n' is read/written. To handle this
* case,
* find the base address of the load/store instruction and append it in the
* stop-info
* packet.
*/
ostr << " " << m_reg_context_up->GetWatchpointHitAddress(wp_index);
m_stop_description = ostr.str();
m_stop_info.reason = StopReason::eStopReasonWatchpoint;
m_stop_info.details.signal.signo = SIGTRAP;
}
bool NativeThreadLinux::IsStoppedAtBreakpoint() {
return GetState() == StateType::eStateStopped &&
m_stop_info.reason == StopReason::eStopReasonBreakpoint;
}
bool NativeThreadLinux::IsStoppedAtWatchpoint() {
return GetState() == StateType::eStateStopped &&
m_stop_info.reason == StopReason::eStopReasonWatchpoint;
}
void NativeThreadLinux::SetStoppedByTrace() {
SetStopped();
m_stop_info.reason = StopReason::eStopReasonTrace;
m_stop_info.details.signal.signo = SIGTRAP;
}
void NativeThreadLinux::SetStoppedWithNoReason() {
SetStopped();
m_stop_info.reason = StopReason::eStopReasonNone;
m_stop_info.details.signal.signo = 0;
}
void NativeThreadLinux::SetExited() {
const StateType new_state = StateType::eStateExited;
MaybeLogStateChange(new_state);
m_state = new_state;
m_stop_info.reason = StopReason::eStopReasonThreadExiting;
}
Status NativeThreadLinux::RequestStop() {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
NativeProcessLinux &process = GetProcess();
lldb::pid_t pid = process.GetID();
lldb::tid_t tid = GetID();
LLDB_LOGF(log,
"NativeThreadLinux::%s requesting thread stop(pid: %" PRIu64
", tid: %" PRIu64 ")",
__FUNCTION__, pid, tid);
Status err;
errno = 0;
if (::tgkill(pid, tid, SIGSTOP) != 0) {
err.SetErrorToErrno();
LLDB_LOGF(log,
"NativeThreadLinux::%s tgkill(%" PRIu64 ", %" PRIu64
", SIGSTOP) failed: %s",
__FUNCTION__, pid, tid, err.AsCString());
}
return err;
}
void NativeThreadLinux::MaybeLogStateChange(lldb::StateType new_state) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
// If we're not logging, we're done.
if (!log)
return;
// If this is a state change to the same state, we're done.
lldb::StateType old_state = m_state;
if (new_state == old_state)
return;
LLDB_LOG(log, "pid={0}, tid={1}: changing from state {2} to {3}",
m_process.GetID(), GetID(), old_state, new_state);
}
NativeProcessLinux &NativeThreadLinux::GetProcess() {
return static_cast<NativeProcessLinux &>(m_process);
}