//===-- NativeProcessLinux.cpp -------------------------------- -*- C++ -*-===//
//
// 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 "NativeProcessLinux.h"
#include <errno.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <fstream>
#include <mutex>
#include <sstream>
#include <string>
#include <unordered_map>
#include "lldb/Core/EmulateInstruction.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Host/Host.h"
#include "lldb/Host/HostProcess.h"
#include "lldb/Host/ProcessLaunchInfo.h"
#include "lldb/Host/PseudoTerminal.h"
#include "lldb/Host/ThreadLauncher.h"
#include "lldb/Host/common/NativeRegisterContext.h"
#include "lldb/Host/linux/Ptrace.h"
#include "lldb/Host/linux/Uio.h"
#include "lldb/Host/posix/ProcessLauncherPosixFork.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/Utility/RegisterValue.h"
#include "lldb/Utility/State.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/StringExtractor.h"
#include "llvm/Support/Errno.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Threading.h"
#include "NativeThreadLinux.h"
#include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
#include "Plugins/Process/Utility/LinuxProcMaps.h"
#include "Procfs.h"
#include <linux/unistd.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/wait.h>
// Support hardware breakpoints in case it has not been defined
#ifndef TRAP_HWBKPT
#define TRAP_HWBKPT 4
#endif
using namespace lldb;
using namespace lldb_private;
using namespace lldb_private::process_linux;
using namespace llvm;
// Private bits we only need internally.
static bool ProcessVmReadvSupported() {
static bool is_supported;
static llvm::once_flag flag;
llvm::call_once(flag, [] {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
uint32_t source = 0x47424742;
uint32_t dest = 0;
struct iovec local, remote;
remote.iov_base = &source;
local.iov_base = &dest;
remote.iov_len = local.iov_len = sizeof source;
// We shall try if cross-process-memory reads work by attempting to read a
// value from our own process.
ssize_t res = process_vm_readv(getpid(), &local, 1, &remote, 1, 0);
is_supported = (res == sizeof(source) && source == dest);
if (is_supported)
LLDB_LOG(log,
"Detected kernel support for process_vm_readv syscall. "
"Fast memory reads enabled.");
else
LLDB_LOG(log,
"syscall process_vm_readv failed (error: {0}). Fast memory "
"reads disabled.",
llvm::sys::StrError());
});
return is_supported;
}
namespace {
void MaybeLogLaunchInfo(const ProcessLaunchInfo &info) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
if (!log)
return;
if (const FileAction *action = info.GetFileActionForFD(STDIN_FILENO))
LLDB_LOG(log, "setting STDIN to '{0}'", action->GetFileSpec());
else
LLDB_LOG(log, "leaving STDIN as is");
if (const FileAction *action = info.GetFileActionForFD(STDOUT_FILENO))
LLDB_LOG(log, "setting STDOUT to '{0}'", action->GetFileSpec());
else
LLDB_LOG(log, "leaving STDOUT as is");
if (const FileAction *action = info.GetFileActionForFD(STDERR_FILENO))
LLDB_LOG(log, "setting STDERR to '{0}'", action->GetFileSpec());
else
LLDB_LOG(log, "leaving STDERR as is");
int i = 0;
for (const char **args = info.GetArguments().GetConstArgumentVector(); *args;
++args, ++i)
LLDB_LOG(log, "arg {0}: '{1}'", i, *args);
}
void DisplayBytes(StreamString &s, void *bytes, uint32_t count) {
uint8_t *ptr = (uint8_t *)bytes;
const uint32_t loop_count = std::min<uint32_t>(DEBUG_PTRACE_MAXBYTES, count);
for (uint32_t i = 0; i < loop_count; i++) {
s.Printf("[%x]", *ptr);
ptr++;
}
}
void PtraceDisplayBytes(int &req, void *data, size_t data_size) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
if (!log)
return;
StreamString buf;
switch (req) {
case PTRACE_POKETEXT: {
DisplayBytes(buf, &data, 8);
LLDB_LOGV(log, "PTRACE_POKETEXT {0}", buf.GetData());
break;
}
case PTRACE_POKEDATA: {
DisplayBytes(buf, &data, 8);
LLDB_LOGV(log, "PTRACE_POKEDATA {0}", buf.GetData());
break;
}
case PTRACE_POKEUSER: {
DisplayBytes(buf, &data, 8);
LLDB_LOGV(log, "PTRACE_POKEUSER {0}", buf.GetData());
break;
}
case PTRACE_SETREGS: {
DisplayBytes(buf, data, data_size);
LLDB_LOGV(log, "PTRACE_SETREGS {0}", buf.GetData());
break;
}
case PTRACE_SETFPREGS: {
DisplayBytes(buf, data, data_size);
LLDB_LOGV(log, "PTRACE_SETFPREGS {0}", buf.GetData());
break;
}
case PTRACE_SETSIGINFO: {
DisplayBytes(buf, data, sizeof(siginfo_t));
LLDB_LOGV(log, "PTRACE_SETSIGINFO {0}", buf.GetData());
break;
}
case PTRACE_SETREGSET: {
// Extract iov_base from data, which is a pointer to the struct iovec
DisplayBytes(buf, *(void **)data, data_size);
LLDB_LOGV(log, "PTRACE_SETREGSET {0}", buf.GetData());
break;
}
default: {}
}
}
static constexpr unsigned k_ptrace_word_size = sizeof(void *);
static_assert(sizeof(long) >= k_ptrace_word_size,
"Size of long must be larger than ptrace word size");
} // end of anonymous namespace
// Simple helper function to ensure flags are enabled on the given file
// descriptor.
static Status EnsureFDFlags(int fd, int flags) {
Status error;
int status = fcntl(fd, F_GETFL);
if (status == -1) {
error.SetErrorToErrno();
return error;
}
if (fcntl(fd, F_SETFL, status | flags) == -1) {
error.SetErrorToErrno();
return error;
}
return error;
}
// Public Static Methods
llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
NativeProcessLinux::Factory::Launch(ProcessLaunchInfo &launch_info,
NativeDelegate &native_delegate,
MainLoop &mainloop) const {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
MaybeLogLaunchInfo(launch_info);
Status status;
::pid_t pid = ProcessLauncherPosixFork()
.LaunchProcess(launch_info, status)
.GetProcessId();
LLDB_LOG(log, "pid = {0:x}", pid);
if (status.Fail()) {
LLDB_LOG(log, "failed to launch process: {0}", status);
return status.ToError();
}
// Wait for the child process to trap on its call to execve.
int wstatus;
::pid_t wpid = llvm::sys::RetryAfterSignal(-1, ::waitpid, pid, &wstatus, 0);
assert(wpid == pid);
(void)wpid;
if (!WIFSTOPPED(wstatus)) {
LLDB_LOG(log, "Could not sync with inferior process: wstatus={1}",
WaitStatus::Decode(wstatus));
return llvm::make_error<StringError>("Could not sync with inferior process",
llvm::inconvertibleErrorCode());
}
LLDB_LOG(log, "inferior started, now in stopped state");
ProcessInstanceInfo Info;
if (!Host::GetProcessInfo(pid, Info)) {
return llvm::make_error<StringError>("Cannot get process architecture",
llvm::inconvertibleErrorCode());
}
// Set the architecture to the exe architecture.
LLDB_LOG(log, "pid = {0:x}, detected architecture {1}", pid,
Info.GetArchitecture().GetArchitectureName());
status = SetDefaultPtraceOpts(pid);
if (status.Fail()) {
LLDB_LOG(log, "failed to set default ptrace options: {0}", status);
return status.ToError();
}
return std::unique_ptr<NativeProcessLinux>(new NativeProcessLinux(
pid, launch_info.GetPTY().ReleaseMasterFileDescriptor(), native_delegate,
Info.GetArchitecture(), mainloop, {pid}));
}
llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
NativeProcessLinux::Factory::Attach(
lldb::pid_t pid, NativeProcessProtocol::NativeDelegate &native_delegate,
MainLoop &mainloop) const {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
LLDB_LOG(log, "pid = {0:x}", pid);
// Retrieve the architecture for the running process.
ProcessInstanceInfo Info;
if (!Host::GetProcessInfo(pid, Info)) {
return llvm::make_error<StringError>("Cannot get process architecture",
llvm::inconvertibleErrorCode());
}
auto tids_or = NativeProcessLinux::Attach(pid);
if (!tids_or)
return tids_or.takeError();
return std::unique_ptr<NativeProcessLinux>(new NativeProcessLinux(
pid, -1, native_delegate, Info.GetArchitecture(), mainloop, *tids_or));
}
// Public Instance Methods
NativeProcessLinux::NativeProcessLinux(::pid_t pid, int terminal_fd,
NativeDelegate &delegate,
const ArchSpec &arch, MainLoop &mainloop,
llvm::ArrayRef<::pid_t> tids)
: NativeProcessELF(pid, terminal_fd, delegate), m_arch(arch) {
if (m_terminal_fd != -1) {
Status status = EnsureFDFlags(m_terminal_fd, O_NONBLOCK);
assert(status.Success());
}
Status status;
m_sigchld_handle = mainloop.RegisterSignal(
SIGCHLD, [this](MainLoopBase &) { SigchldHandler(); }, status);
assert(m_sigchld_handle && status.Success());
for (const auto &tid : tids) {
NativeThreadLinux &thread = AddThread(tid);
thread.SetStoppedBySignal(SIGSTOP);
ThreadWasCreated(thread);
}
// Let our process instance know the thread has stopped.
SetCurrentThreadID(tids[0]);
SetState(StateType::eStateStopped, false);
// Proccess any signals we received before installing our handler
SigchldHandler();
}
llvm::Expected<std::vector<::pid_t>> NativeProcessLinux::Attach(::pid_t pid) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
Status status;
// Use a map to keep track of the threads which we have attached/need to
// attach.
Host::TidMap tids_to_attach;
while (Host::FindProcessThreads(pid, tids_to_attach)) {
for (Host::TidMap::iterator it = tids_to_attach.begin();
it != tids_to_attach.end();) {
if (it->second == false) {
lldb::tid_t tid = it->first;
// Attach to the requested process.
// An attach will cause the thread to stop with a SIGSTOP.
if ((status = PtraceWrapper(PTRACE_ATTACH, tid)).Fail()) {
// No such thread. The thread may have exited. More error handling
// may be needed.
if (status.GetError() == ESRCH) {
it = tids_to_attach.erase(it);
continue;
}
return status.ToError();
}
int wpid =
llvm::sys::RetryAfterSignal(-1, ::waitpid, tid, nullptr, __WALL);
// Need to use __WALL otherwise we receive an error with errno=ECHLD At
// this point we should have a thread stopped if waitpid succeeds.
if (wpid < 0) {
// No such thread. The thread may have exited. More error handling
// may be needed.
if (errno == ESRCH) {
it = tids_to_attach.erase(it);
continue;
}
return llvm::errorCodeToError(
std::error_code(errno, std::generic_category()));
}
if ((status = SetDefaultPtraceOpts(tid)).Fail())
return status.ToError();
LLDB_LOG(log, "adding tid = {0}", tid);
it->second = true;
}
// move the loop forward
++it;
}
}
size_t tid_count = tids_to_attach.size();
if (tid_count == 0)
return llvm::make_error<StringError>("No such process",
llvm::inconvertibleErrorCode());
std::vector<::pid_t> tids;
tids.reserve(tid_count);
for (const auto &p : tids_to_attach)
tids.push_back(p.first);
return std::move(tids);
}
Status NativeProcessLinux::SetDefaultPtraceOpts(lldb::pid_t pid) {
long ptrace_opts = 0;
// Have the child raise an event on exit. This is used to keep the child in
// limbo until it is destroyed.
ptrace_opts |= PTRACE_O_TRACEEXIT;
// Have the tracer trace threads which spawn in the inferior process.
// TODO: if we want to support tracing the inferiors' child, add the
// appropriate ptrace flags here (PTRACE_O_TRACEFORK, PTRACE_O_TRACEVFORK)
ptrace_opts |= PTRACE_O_TRACECLONE;
// Have the tracer notify us before execve returns (needed to disable legacy
// SIGTRAP generation)
ptrace_opts |= PTRACE_O_TRACEEXEC;
return PtraceWrapper(PTRACE_SETOPTIONS, pid, nullptr, (void *)ptrace_opts);
}
// Handles all waitpid events from the inferior process.
void NativeProcessLinux::MonitorCallback(lldb::pid_t pid, bool exited,
WaitStatus status) {
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS));
// Certain activities differ based on whether the pid is the tid of the main
// thread.
const bool is_main_thread = (pid == GetID());
// Handle when the thread exits.
if (exited) {
LLDB_LOG(log,
"got exit status({0}) , tid = {1} ({2} main thread), process "
"state = {3}",
status, pid, is_main_thread ? "is" : "is not", GetState());
// This is a thread that exited. Ensure we're not tracking it anymore.
StopTrackingThread(pid);
if (is_main_thread) {
// The main thread exited. We're done monitoring. Report to delegate.
SetExitStatus(status, true);
// Notify delegate that our process has exited.
SetState(StateType::eStateExited, true);
}
return;
}
siginfo_t info;
const auto info_err = GetSignalInfo(pid, &info);
auto thread_sp = GetThreadByID(pid);
if (!thread_sp) {
// Normally, the only situation when we cannot find the thread is if we
// have just received a new thread notification. This is indicated by
// GetSignalInfo() returning si_code == SI_USER and si_pid == 0
LLDB_LOG(log, "received notification about an unknown tid {0}.", pid);
if (info_err.Fail()) {
LLDB_LOG(log,
"(tid {0}) GetSignalInfo failed ({1}). "
"Ingoring this notification.",
pid, info_err);
return;
}
LLDB_LOG(log, "tid {0}, si_code: {1}, si_pid: {2}", pid, info.si_code,
info.si_pid);
NativeThreadLinux &thread = AddThread(pid);
// Resume the newly created thread.
ResumeThread(thread, eStateRunning, LLDB_INVALID_SIGNAL_NUMBER);
ThreadWasCreated(thread);
return;
}
// Get details on the signal raised.
if (info_err.Success()) {
// We have retrieved the signal info. Dispatch appropriately.
if (info.si_signo == SIGTRAP)
MonitorSIGTRAP(info, *thread_sp);
else
MonitorSignal(info, *thread_sp, exited);
} else {
if (info_err.GetError() == EINVAL) {
// This is a group stop reception for this tid. We can reach here if we
// reinject SIGSTOP, SIGSTP, SIGTTIN or SIGTTOU into the tracee,
// triggering the group-stop mechanism. Normally receiving these would
// stop the process, pending a SIGCONT. Simulating this state in a
// debugger is hard and is generally not needed (one use case is
// debugging background task being managed by a shell). For general use,
// it is sufficient to stop the process in a signal-delivery stop which
// happens before the group stop. This done by MonitorSignal and works
// correctly for all signals.
LLDB_LOG(log,
"received a group stop for pid {0} tid {1}. Transparent "
"handling of group stops not supported, resuming the "
"thread.",
GetID(), pid);
ResumeThread(*thread_sp, thread_sp->GetState(),
LLDB_INVALID_SIGNAL_NUMBER);
} else {
// ptrace(GETSIGINFO) failed (but not due to group-stop).
// A return value of ESRCH means the thread/process is no longer on the
// system, so it was killed somehow outside of our control. Either way,
// we can't do anything with it anymore.
// Stop tracking the metadata for the thread since it's entirely off the
// system now.
const bool thread_found = StopTrackingThread(pid);
LLDB_LOG(log,
"GetSignalInfo failed: {0}, tid = {1}, status = {2}, "
"status = {3}, main_thread = {4}, thread_found: {5}",
info_err, pid, status, status, is_main_thread, thread_found);
if (is_main_thread) {
// Notify the delegate - our process is not available but appears to
// have been killed outside our control. Is eStateExited the right
// exit state in this case?
SetExitStatus(status, true);
SetState(StateType::eStateExited, true);
} else {
// This thread was pulled out from underneath us. Anything to do here?
// Do we want to do an all stop?
LLDB_LOG(log,
"pid {0} tid {1} non-main thread exit occurred, didn't "
"tell delegate anything since thread disappeared out "
"from underneath us",
GetID(), pid);
}
}
}
}
void NativeProcessLinux::WaitForNewThread(::pid_t tid) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
if (GetThreadByID(tid)) {
// We are already tracking the thread - we got the event on the new thread
// (see MonitorSignal) before this one. We are done.
return;
}
// The thread is not tracked yet, let's wait for it to appear.
int status = -1;
LLDB_LOG(log,
"received thread creation event for tid {0}. tid not tracked "
"yet, waiting for thread to appear...",
tid);
::pid_t wait_pid = llvm::sys::RetryAfterSignal(-1, ::waitpid, tid, &status, __WALL);
// Since we are waiting on a specific tid, this must be the creation event.
// But let's do some checks just in case.
if (wait_pid != tid) {
LLDB_LOG(log,
"waiting for tid {0} failed. Assuming the thread has "
"disappeared in the meantime",
tid);
// The only way I know of this could happen is if the whole process was
// SIGKILLed in the mean time. In any case, we can't do anything about that
// now.
return;
}
if (WIFEXITED(status)) {
LLDB_LOG(log,
"waiting for tid {0} returned an 'exited' event. Not "
"tracking the thread.",
tid);
// Also a very improbable event.
return;
}
LLDB_LOG(log, "pid = {0}: tracking new thread tid {1}", GetID(), tid);
NativeThreadLinux &new_thread = AddThread(tid);
ResumeThread(new_thread, eStateRunning, LLDB_INVALID_SIGNAL_NUMBER);
ThreadWasCreated(new_thread);
}
void NativeProcessLinux::MonitorSIGTRAP(const siginfo_t &info,
NativeThreadLinux &thread) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
const bool is_main_thread = (thread.GetID() == GetID());
assert(info.si_signo == SIGTRAP && "Unexpected child signal!");
switch (info.si_code) {
// TODO: these two cases are required if we want to support tracing of the
// inferiors' children. We'd need this to debug a monitor. case (SIGTRAP |
// (PTRACE_EVENT_FORK << 8)): case (SIGTRAP | (PTRACE_EVENT_VFORK << 8)):
case (SIGTRAP | (PTRACE_EVENT_CLONE << 8)): {
// This is the notification on the parent thread which informs us of new
// thread creation. We don't want to do anything with the parent thread so
// we just resume it. In case we want to implement "break on thread
// creation" functionality, we would need to stop here.
unsigned long event_message = 0;
if (GetEventMessage(thread.GetID(), &event_message).Fail()) {
LLDB_LOG(log,
"pid {0} received thread creation event but "
"GetEventMessage failed so we don't know the new tid",
thread.GetID());
} else
WaitForNewThread(event_message);
ResumeThread(thread, thread.GetState(), LLDB_INVALID_SIGNAL_NUMBER);
break;
}
case (SIGTRAP | (PTRACE_EVENT_EXEC << 8)): {
LLDB_LOG(log, "received exec event, code = {0}", info.si_code ^ SIGTRAP);
// Exec clears any pending notifications.
m_pending_notification_tid = LLDB_INVALID_THREAD_ID;
// Remove all but the main thread here. Linux fork creates a new process
// which only copies the main thread.
LLDB_LOG(log, "exec received, stop tracking all but main thread");
llvm::erase_if(m_threads, [&](std::unique_ptr<NativeThreadProtocol> &t) {
return t->GetID() != GetID();
});
assert(m_threads.size() == 1);
auto *main_thread = static_cast<NativeThreadLinux *>(m_threads[0].get());
SetCurrentThreadID(main_thread->GetID());
main_thread->SetStoppedByExec();
// Tell coordinator about about the "new" (since exec) stopped main thread.
ThreadWasCreated(*main_thread);
// Let our delegate know we have just exec'd.
NotifyDidExec();
// Let the process know we're stopped.
StopRunningThreads(main_thread->GetID());
break;
}
case (SIGTRAP | (PTRACE_EVENT_EXIT << 8)): {
// The inferior process or one of its threads is about to exit. We don't
// want to do anything with the thread so we just resume it. In case we
// want to implement "break on thread exit" functionality, we would need to
// stop here.
unsigned long data = 0;
if (GetEventMessage(thread.GetID(), &data).Fail())
data = -1;
LLDB_LOG(log,
"received PTRACE_EVENT_EXIT, data = {0:x}, WIFEXITED={1}, "
"WIFSIGNALED={2}, pid = {3}, main_thread = {4}",
data, WIFEXITED(data), WIFSIGNALED(data), thread.GetID(),
is_main_thread);
StateType state = thread.GetState();
if (!StateIsRunningState(state)) {
// Due to a kernel bug, we may sometimes get this stop after the inferior
// gets a SIGKILL. This confuses our state tracking logic in
// ResumeThread(), since normally, we should not be receiving any ptrace
// events while the inferior is stopped. This makes sure that the
// inferior is resumed and exits normally.
state = eStateRunning;
}
ResumeThread(thread, state, LLDB_INVALID_SIGNAL_NUMBER);
break;
}
case 0:
case TRAP_TRACE: // We receive this on single stepping.
case TRAP_HWBKPT: // We receive this on watchpoint hit
{
// If a watchpoint was hit, report it
uint32_t wp_index;
Status error = thread.GetRegisterContext().GetWatchpointHitIndex(
wp_index, (uintptr_t)info.si_addr);
if (error.Fail())
LLDB_LOG(log,
"received error while checking for watchpoint hits, pid = "
"{0}, error = {1}",
thread.GetID(), error);
if (wp_index != LLDB_INVALID_INDEX32) {
MonitorWatchpoint(thread, wp_index);
break;
}
// If a breakpoint was hit, report it
uint32_t bp_index;
error = thread.GetRegisterContext().GetHardwareBreakHitIndex(
bp_index, (uintptr_t)info.si_addr);
if (error.Fail())
LLDB_LOG(log, "received error while checking for hardware "
"breakpoint hits, pid = {0}, error = {1}",
thread.GetID(), error);
if (bp_index != LLDB_INVALID_INDEX32) {
MonitorBreakpoint(thread);
break;
}
// Otherwise, report step over
MonitorTrace(thread);
break;
}
case SI_KERNEL:
#if defined __mips__
// For mips there is no special signal for watchpoint So we check for
// watchpoint in kernel trap
{
// If a watchpoint was hit, report it
uint32_t wp_index;
Status error = thread.GetRegisterContext().GetWatchpointHitIndex(
wp_index, LLDB_INVALID_ADDRESS);
if (error.Fail())
LLDB_LOG(log,
"received error while checking for watchpoint hits, pid = "
"{0}, error = {1}",
thread.GetID(), error);
if (wp_index != LLDB_INVALID_INDEX32) {
MonitorWatchpoint(thread, wp_index);
break;
}
}
// NO BREAK
#endif
case TRAP_BRKPT:
MonitorBreakpoint(thread);
break;
case SIGTRAP:
case (SIGTRAP | 0x80):
LLDB_LOG(
log,
"received unknown SIGTRAP stop event ({0}, pid {1} tid {2}, resuming",
info.si_code, GetID(), thread.GetID());
// Ignore these signals until we know more about them.
ResumeThread(thread, thread.GetState(), LLDB_INVALID_SIGNAL_NUMBER);
break;
default:
LLDB_LOG(log, "received unknown SIGTRAP stop event ({0}, pid {1} tid {2}",
info.si_code, GetID(), thread.GetID());
MonitorSignal(info, thread, false);
break;
}
}
void NativeProcessLinux::MonitorTrace(NativeThreadLinux &thread) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
LLDB_LOG(log, "received trace event, pid = {0}", thread.GetID());
// This thread is currently stopped.
thread.SetStoppedByTrace();
StopRunningThreads(thread.GetID());
}
void NativeProcessLinux::MonitorBreakpoint(NativeThreadLinux &thread) {
Log *log(
GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS | LIBLLDB_LOG_BREAKPOINTS));
LLDB_LOG(log, "received breakpoint event, pid = {0}", thread.GetID());
// Mark the thread as stopped at breakpoint.
thread.SetStoppedByBreakpoint();
FixupBreakpointPCAsNeeded(thread);
if (m_threads_stepping_with_breakpoint.find(thread.GetID()) !=
m_threads_stepping_with_breakpoint.end())
thread.SetStoppedByTrace();
StopRunningThreads(thread.GetID());
}
void NativeProcessLinux::MonitorWatchpoint(NativeThreadLinux &thread,
uint32_t wp_index) {
Log *log(
GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS | LIBLLDB_LOG_WATCHPOINTS));
LLDB_LOG(log, "received watchpoint event, pid = {0}, wp_index = {1}",
thread.GetID(), wp_index);
// Mark the thread as stopped at watchpoint. The address is at
// (lldb::addr_t)info->si_addr if we need it.
thread.SetStoppedByWatchpoint(wp_index);
// We need to tell all other running threads before we notify the delegate
// about this stop.
StopRunningThreads(thread.GetID());
}
void NativeProcessLinux::MonitorSignal(const siginfo_t &info,
NativeThreadLinux &thread, bool exited) {
const int signo = info.si_signo;
const bool is_from_llgs = info.si_pid == getpid();
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
// POSIX says that process behaviour is undefined after it ignores a SIGFPE,
// SIGILL, SIGSEGV, or SIGBUS *unless* that signal was generated by a kill(2)
// or raise(3). Similarly for tgkill(2) on Linux.
//
// IOW, user generated signals never generate what we consider to be a
// "crash".
//
// Similarly, ACK signals generated by this monitor.
// Handle the signal.
LLDB_LOG(log,
"received signal {0} ({1}) with code {2}, (siginfo pid = {3}, "
"waitpid pid = {4})",
Host::GetSignalAsCString(signo), signo, info.si_code,
thread.GetID());
// Check for thread stop notification.
if (is_from_llgs && (info.si_code == SI_TKILL) && (signo == SIGSTOP)) {
// This is a tgkill()-based stop.
LLDB_LOG(log, "pid {0} tid {1}, thread stopped", GetID(), thread.GetID());
// Check that we're not already marked with a stop reason. Note this thread
// really shouldn't already be marked as stopped - if we were, that would
// imply that the kernel signaled us with the thread stopping which we
// handled and marked as stopped, and that, without an intervening resume,
// we received another stop. It is more likely that we are missing the
// marking of a run state somewhere if we find that the thread was marked
// as stopped.
const StateType thread_state = thread.GetState();
if (!StateIsStoppedState(thread_state, false)) {
// An inferior thread has stopped because of a SIGSTOP we have sent it.
// Generally, these are not important stops and we don't want to report
// them as they are just used to stop other threads when one thread (the
// one with the *real* stop reason) hits a breakpoint (watchpoint,
// etc...). However, in the case of an asynchronous Interrupt(), this
// *is* the real stop reason, so we leave the signal intact if this is
// the thread that was chosen as the triggering thread.
if (m_pending_notification_tid != LLDB_INVALID_THREAD_ID) {
if (m_pending_notification_tid == thread.GetID())
thread.SetStoppedBySignal(SIGSTOP, &info);
else
thread.SetStoppedWithNoReason();
SetCurrentThreadID(thread.GetID());
SignalIfAllThreadsStopped();
} else {
// We can end up here if stop was initiated by LLGS but by this time a
// thread stop has occurred - maybe initiated by another event.
Status error = ResumeThread(thread, thread.GetState(), 0);
if (error.Fail())
LLDB_LOG(log, "failed to resume thread {0}: {1}", thread.GetID(),
error);
}
} else {
LLDB_LOG(log,
"pid {0} tid {1}, thread was already marked as a stopped "
"state (state={2}), leaving stop signal as is",
GetID(), thread.GetID(), thread_state);
SignalIfAllThreadsStopped();
}
// Done handling.
return;
}
// Check if debugger should stop at this signal or just ignore it and resume
// the inferior.
if (m_signals_to_ignore.find(signo) != m_signals_to_ignore.end()) {
ResumeThread(thread, thread.GetState(), signo);
return;
}
// This thread is stopped.
LLDB_LOG(log, "received signal {0}", Host::GetSignalAsCString(signo));
thread.SetStoppedBySignal(signo, &info);
// Send a stop to the debugger after we get all other threads to stop.
StopRunningThreads(thread.GetID());
}
namespace {
struct EmulatorBaton {
NativeProcessLinux &m_process;
NativeRegisterContext &m_reg_context;
// eRegisterKindDWARF -> RegsiterValue
std::unordered_map<uint32_t, RegisterValue> m_register_values;
EmulatorBaton(NativeProcessLinux &process, NativeRegisterContext ®_context)
: m_process(process), m_reg_context(reg_context) {}
};
} // anonymous namespace
static size_t ReadMemoryCallback(EmulateInstruction *instruction, void *baton,
const EmulateInstruction::Context &context,
lldb::addr_t addr, void *dst, size_t length) {
EmulatorBaton *emulator_baton = static_cast<EmulatorBaton *>(baton);
size_t bytes_read;
emulator_baton->m_process.ReadMemory(addr, dst, length, bytes_read);
return bytes_read;
}
static bool ReadRegisterCallback(EmulateInstruction *instruction, void *baton,
const RegisterInfo *reg_info,
RegisterValue ®_value) {
EmulatorBaton *emulator_baton = static_cast<EmulatorBaton *>(baton);
auto it = emulator_baton->m_register_values.find(
reg_info->kinds[eRegisterKindDWARF]);
if (it != emulator_baton->m_register_values.end()) {
reg_value = it->second;
return true;
}
// The emulator only fill in the dwarf regsiter numbers (and in some case the
// generic register numbers). Get the full register info from the register
// context based on the dwarf register numbers.
const RegisterInfo *full_reg_info =
emulator_baton->m_reg_context.GetRegisterInfo(
eRegisterKindDWARF, reg_info->kinds[eRegisterKindDWARF]);
Status error =
emulator_baton->m_reg_context.ReadRegister(full_reg_info, reg_value);
if (error.Success())
return true;
return false;
}
static bool WriteRegisterCallback(EmulateInstruction *instruction, void *baton,
const EmulateInstruction::Context &context,
const RegisterInfo *reg_info,
const RegisterValue ®_value) {
EmulatorBaton *emulator_baton = static_cast<EmulatorBaton *>(baton);
emulator_baton->m_register_values[reg_info->kinds[eRegisterKindDWARF]] =
reg_value;
return true;
}
static size_t WriteMemoryCallback(EmulateInstruction *instruction, void *baton,
const EmulateInstruction::Context &context,
lldb::addr_t addr, const void *dst,
size_t length) {
return length;
}
static lldb::addr_t ReadFlags(NativeRegisterContext ®siter_context) {
const RegisterInfo *flags_info = regsiter_context.GetRegisterInfo(
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_FLAGS);
return regsiter_context.ReadRegisterAsUnsigned(flags_info,
LLDB_INVALID_ADDRESS);
}
Status
NativeProcessLinux::SetupSoftwareSingleStepping(NativeThreadLinux &thread) {
Status error;
NativeRegisterContext& register_context = thread.GetRegisterContext();
std::unique_ptr<EmulateInstruction> emulator_up(
EmulateInstruction::FindPlugin(m_arch, eInstructionTypePCModifying,
nullptr));
if (emulator_up == nullptr)
return Status("Instruction emulator not found!");
EmulatorBaton baton(*this, register_context);
emulator_up->SetBaton(&baton);
emulator_up->SetReadMemCallback(&ReadMemoryCallback);
emulator_up->SetReadRegCallback(&ReadRegisterCallback);
emulator_up->SetWriteMemCallback(&WriteMemoryCallback);
emulator_up->SetWriteRegCallback(&WriteRegisterCallback);
if (!emulator_up->ReadInstruction())
return Status("Read instruction failed!");
bool emulation_result =
emulator_up->EvaluateInstruction(eEmulateInstructionOptionAutoAdvancePC);
const RegisterInfo *reg_info_pc = register_context.GetRegisterInfo(
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
const RegisterInfo *reg_info_flags = register_context.GetRegisterInfo(
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_FLAGS);
auto pc_it =
baton.m_register_values.find(reg_info_pc->kinds[eRegisterKindDWARF]);
auto flags_it =
baton.m_register_values.find(reg_info_flags->kinds[eRegisterKindDWARF]);
lldb::addr_t next_pc;
lldb::addr_t next_flags;
if (emulation_result) {
assert(pc_it != baton.m_register_values.end() &&
"Emulation was successfull but PC wasn't updated");
next_pc = pc_it->second.GetAsUInt64();
if (flags_it != baton.m_register_values.end())
next_flags = flags_it->second.GetAsUInt64();
else
next_flags = ReadFlags(register_context);
} else if (pc_it == baton.m_register_values.end()) {
// Emulate instruction failed and it haven't changed PC. Advance PC with
// the size of the current opcode because the emulation of all
// PC modifying instruction should be successful. The failure most
// likely caused by a not supported instruction which don't modify PC.
next_pc = register_context.GetPC() + emulator_up->GetOpcode().GetByteSize();
next_flags = ReadFlags(register_context);
} else {
// The instruction emulation failed after it modified the PC. It is an
// unknown error where we can't continue because the next instruction is
// modifying the PC but we don't know how.
return Status("Instruction emulation failed unexpectedly.");
}
if (m_arch.GetMachine() == llvm::Triple::arm) {
if (next_flags & 0x20) {
// Thumb mode
error = SetSoftwareBreakpoint(next_pc, 2);
} else {
// Arm mode
error = SetSoftwareBreakpoint(next_pc, 4);
}
} else if (m_arch.IsMIPS() || m_arch.GetTriple().isPPC64())
error = SetSoftwareBreakpoint(next_pc, 4);
else {
// No size hint is given for the next breakpoint
error = SetSoftwareBreakpoint(next_pc, 0);
}
// If setting the breakpoint fails because next_pc is out of the address
// space, ignore it and let the debugee segfault.
if (error.GetError() == EIO || error.GetError() == EFAULT) {
return Status();
} else if (error.Fail())
return error;
m_threads_stepping_with_breakpoint.insert({thread.GetID(), next_pc});
return Status();
}
bool NativeProcessLinux::SupportHardwareSingleStepping() const {
if (m_arch.GetMachine() == llvm::Triple::arm || m_arch.IsMIPS())
return false;
return true;
}
Status NativeProcessLinux::Resume(const ResumeActionList &resume_actions) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
LLDB_LOG(log, "pid {0}", GetID());
bool software_single_step = !SupportHardwareSingleStepping();
if (software_single_step) {
for (const auto &thread : m_threads) {
assert(thread && "thread list should not contain NULL threads");
const ResumeAction *const action =
resume_actions.GetActionForThread(thread->GetID(), true);
if (action == nullptr)
continue;
if (action->state == eStateStepping) {
Status error = SetupSoftwareSingleStepping(
static_cast<NativeThreadLinux &>(*thread));
if (error.Fail())
return error;
}
}
}
for (const auto &thread : m_threads) {
assert(thread && "thread list should not contain NULL threads");
const ResumeAction *const action =
resume_actions.GetActionForThread(thread->GetID(), true);
if (action == nullptr) {
LLDB_LOG(log, "no action specified for pid {0} tid {1}", GetID(),
thread->GetID());
continue;
}
LLDB_LOG(log, "processing resume action state {0} for pid {1} tid {2}",
action->state, GetID(), thread->GetID());
switch (action->state) {
case eStateRunning:
case eStateStepping: {
// Run the thread, possibly feeding it the signal.
const int signo = action->signal;
ResumeThread(static_cast<NativeThreadLinux &>(*thread), action->state,
signo);
break;
}
case eStateSuspended:
case eStateStopped:
llvm_unreachable("Unexpected state");
default:
return Status("NativeProcessLinux::%s (): unexpected state %s specified "
"for pid %" PRIu64 ", tid %" PRIu64,
__FUNCTION__, StateAsCString(action->state), GetID(),
thread->GetID());
}
}
return Status();
}
Status NativeProcessLinux::Halt() {
Status error;
if (kill(GetID(), SIGSTOP) != 0)
error.SetErrorToErrno();
return error;
}
Status NativeProcessLinux::Detach() {
Status error;
// Stop monitoring the inferior.
m_sigchld_handle.reset();
// Tell ptrace to detach from the process.
if (GetID() == LLDB_INVALID_PROCESS_ID)
return error;
for (const auto &thread : m_threads) {
Status e = Detach(thread->GetID());
if (e.Fail())
error =
e; // Save the error, but still attempt to detach from other threads.
}
m_processor_trace_monitor.clear();
m_pt_proces_trace_id = LLDB_INVALID_UID;
return error;
}
Status NativeProcessLinux::Signal(int signo) {
Status error;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
LLDB_LOG(log, "sending signal {0} ({1}) to pid {1}", signo,
Host::GetSignalAsCString(signo), GetID());
if (kill(GetID(), signo))
error.SetErrorToErrno();
return error;
}
Status NativeProcessLinux::Interrupt() {
// Pick a running thread (or if none, a not-dead stopped thread) as the
// chosen thread that will be the stop-reason thread.
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
NativeThreadProtocol *running_thread = nullptr;
NativeThreadProtocol *stopped_thread = nullptr;
LLDB_LOG(log, "selecting running thread for interrupt target");
for (const auto &thread : m_threads) {
// If we have a running or stepping thread, we'll call that the target of
// the interrupt.
const auto thread_state = thread->GetState();
if (thread_state == eStateRunning || thread_state == eStateStepping) {
running_thread = thread.get();
break;
} else if (!stopped_thread && StateIsStoppedState(thread_state, true)) {
// Remember the first non-dead stopped thread. We'll use that as a
// backup if there are no running threads.
stopped_thread = thread.get();
}
}
if (!running_thread && !stopped_thread) {
Status error("found no running/stepping or live stopped threads as target "
"for interrupt");
LLDB_LOG(log, "skipping due to error: {0}", error);
return error;
}
NativeThreadProtocol *deferred_signal_thread =
running_thread ? running_thread : stopped_thread;
LLDB_LOG(log, "pid {0} {1} tid {2} chosen for interrupt target", GetID(),
running_thread ? "running" : "stopped",
deferred_signal_thread->GetID());
StopRunningThreads(deferred_signal_thread->GetID());
return Status();
}
Status NativeProcessLinux::Kill() {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
LLDB_LOG(log, "pid {0}", GetID());
Status error;
switch (m_state) {
case StateType::eStateInvalid:
case StateType::eStateExited:
case StateType::eStateCrashed:
case StateType::eStateDetached:
case StateType::eStateUnloaded:
// Nothing to do - the process is already dead.
LLDB_LOG(log, "ignored for PID {0} due to current state: {1}", GetID(),
m_state);
return error;
case StateType::eStateConnected:
case StateType::eStateAttaching:
case StateType::eStateLaunching:
case StateType::eStateStopped:
case StateType::eStateRunning:
case StateType::eStateStepping:
case StateType::eStateSuspended:
// We can try to kill a process in these states.
break;
}
if (kill(GetID(), SIGKILL) != 0) {
error.SetErrorToErrno();
return error;
}
return error;
}
Status NativeProcessLinux::GetMemoryRegionInfo(lldb::addr_t load_addr,
MemoryRegionInfo &range_info) {
// FIXME review that the final memory region returned extends to the end of
// the virtual address space,
// with no perms if it is not mapped.
// Use an approach that reads memory regions from /proc/{pid}/maps. Assume
// proc maps entries are in ascending order.
// FIXME assert if we find differently.
if (m_supports_mem_region == LazyBool::eLazyBoolNo) {
// We're done.
return Status("unsupported");
}
Status error = PopulateMemoryRegionCache();
if (error.Fail()) {
return error;
}
lldb::addr_t prev_base_address = 0;
// FIXME start by finding the last region that is <= target address using
// binary search. Data is sorted.
// There can be a ton of regions on pthreads apps with lots of threads.
for (auto it = m_mem_region_cache.begin(); it != m_mem_region_cache.end();
++it) {
MemoryRegionInfo &proc_entry_info = it->first;
// Sanity check assumption that /proc/{pid}/maps entries are ascending.
assert((proc_entry_info.GetRange().GetRangeBase() >= prev_base_address) &&
"descending /proc/pid/maps entries detected, unexpected");
prev_base_address = proc_entry_info.GetRange().GetRangeBase();
UNUSED_IF_ASSERT_DISABLED(prev_base_address);
// If the target address comes before this entry, indicate distance to next
// region.
if (load_addr < proc_entry_info.GetRange().GetRangeBase()) {
range_info.GetRange().SetRangeBase(load_addr);
range_info.GetRange().SetByteSize(
proc_entry_info.GetRange().GetRangeBase() - load_addr);
range_info.SetReadable(MemoryRegionInfo::OptionalBool::eNo);
range_info.SetWritable(MemoryRegionInfo::OptionalBool::eNo);
range_info.SetExecutable(MemoryRegionInfo::OptionalBool::eNo);
range_info.SetMapped(MemoryRegionInfo::OptionalBool::eNo);
return error;
} else if (proc_entry_info.GetRange().Contains(load_addr)) {
// The target address is within the memory region we're processing here.
range_info = proc_entry_info;
return error;
}
// The target memory address comes somewhere after the region we just
// parsed.
}
// If we made it here, we didn't find an entry that contained the given
// address. Return the load_addr as start and the amount of bytes betwwen
// load address and the end of the memory as size.
range_info.GetRange().SetRangeBase(load_addr);
range_info.GetRange().SetRangeEnd(LLDB_INVALID_ADDRESS);
range_info.SetReadable(MemoryRegionInfo::OptionalBool::eNo);
range_info.SetWritable(MemoryRegionInfo::OptionalBool::eNo);
range_info.SetExecutable(MemoryRegionInfo::OptionalBool::eNo);
range_info.SetMapped(MemoryRegionInfo::OptionalBool::eNo);
return error;
}
Status NativeProcessLinux::PopulateMemoryRegionCache() {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
// If our cache is empty, pull the latest. There should always be at least
// one memory region if memory region handling is supported.
if (!m_mem_region_cache.empty()) {
LLDB_LOG(log, "reusing {0} cached memory region entries",
m_mem_region_cache.size());
return Status();
}
auto BufferOrError = getProcFile(GetID(), "maps");
if (!BufferOrError) {
m_supports_mem_region = LazyBool::eLazyBoolNo;
return BufferOrError.getError();
}
Status Result;
ParseLinuxMapRegions(BufferOrError.get()->getBuffer(),
[&](const MemoryRegionInfo &Info, const Status &ST) {
if (ST.Success()) {
FileSpec file_spec(Info.GetName().GetCString());
FileSystem::Instance().Resolve(file_spec);
m_mem_region_cache.emplace_back(Info, file_spec);
return true;
} else {
m_supports_mem_region = LazyBool::eLazyBoolNo;
LLDB_LOG(log, "failed to parse proc maps: {0}", ST);
Result = ST;
return false;
}
});
if (Result.Fail())
return Result;
if (m_mem_region_cache.empty()) {
// No entries after attempting to read them. This shouldn't happen if
// /proc/{pid}/maps is supported. Assume we don't support map entries via
// procfs.
m_supports_mem_region = LazyBool::eLazyBoolNo;
LLDB_LOG(log,
"failed to find any procfs maps entries, assuming no support "
"for memory region metadata retrieval");
return Status("not supported");
}
LLDB_LOG(log, "read {0} memory region entries from /proc/{1}/maps",
m_mem_region_cache.size(), GetID());
// We support memory retrieval, remember that.
m_supports_mem_region = LazyBool::eLazyBoolYes;
return Status();
}
void NativeProcessLinux::DoStopIDBumped(uint32_t newBumpId) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
LLDB_LOG(log, "newBumpId={0}", newBumpId);
LLDB_LOG(log, "clearing {0} entries from memory region cache",
m_mem_region_cache.size());
m_mem_region_cache.clear();
}
Status NativeProcessLinux::AllocateMemory(size_t size, uint32_t permissions,
lldb::addr_t &addr) {
// FIXME implementing this requires the equivalent of
// InferiorCallPOSIX::InferiorCallMmap, which depends on functional ThreadPlans
// working with Native*Protocol.
#if 1
return Status("not implemented yet");
#else
addr = LLDB_INVALID_ADDRESS;
unsigned prot = 0;
if (permissions & lldb::ePermissionsReadable)
prot |= eMmapProtRead;
if (permissions & lldb::ePermissionsWritable)
prot |= eMmapProtWrite;
if (permissions & lldb::ePermissionsExecutable)
prot |= eMmapProtExec;
// TODO implement this directly in NativeProcessLinux
// (and lift to NativeProcessPOSIX if/when that class is refactored out).
if (InferiorCallMmap(this, addr, 0, size, prot,
eMmapFlagsAnon | eMmapFlagsPrivate, -1, 0)) {
m_addr_to_mmap_size[addr] = size;
return Status();
} else {
addr = LLDB_INVALID_ADDRESS;
return Status("unable to allocate %" PRIu64
" bytes of memory with permissions %s",
size, GetPermissionsAsCString(permissions));
}
#endif
}
Status NativeProcessLinux::DeallocateMemory(lldb::addr_t addr) {
// FIXME see comments in AllocateMemory - required lower-level
// bits not in place yet (ThreadPlans)
return Status("not implemented");
}
size_t NativeProcessLinux::UpdateThreads() {
// The NativeProcessLinux monitoring threads are always up to date with
// respect to thread state and they keep the thread list populated properly.
// All this method needs to do is return the thread count.
return m_threads.size();
}
Status NativeProcessLinux::SetBreakpoint(lldb::addr_t addr, uint32_t size,
bool hardware) {
if (hardware)
return SetHardwareBreakpoint(addr, size);
else
return SetSoftwareBreakpoint(addr, size);
}
Status NativeProcessLinux::RemoveBreakpoint(lldb::addr_t addr, bool hardware) {
if (hardware)
return RemoveHardwareBreakpoint(addr);
else
return NativeProcessProtocol::RemoveBreakpoint(addr);
}
llvm::Expected<llvm::ArrayRef<uint8_t>>
NativeProcessLinux::GetSoftwareBreakpointTrapOpcode(size_t size_hint) {
// The ARM reference recommends the use of 0xe7fddefe and 0xdefe but the
// linux kernel does otherwise.
static const uint8_t g_arm_opcode[] = {0xf0, 0x01, 0xf0, 0xe7};
static const uint8_t g_thumb_opcode[] = {0x01, 0xde};
switch (GetArchitecture().GetMachine()) {
case llvm::Triple::arm:
switch (size_hint) {
case 2:
return llvm::makeArrayRef(g_thumb_opcode);
case 4:
return llvm::makeArrayRef(g_arm_opcode);
default:
return llvm::createStringError(llvm::inconvertibleErrorCode(),
"Unrecognised trap opcode size hint!");
}
default:
return NativeProcessProtocol::GetSoftwareBreakpointTrapOpcode(size_hint);
}
}
Status NativeProcessLinux::ReadMemory(lldb::addr_t addr, void *buf, size_t size,
size_t &bytes_read) {
if (ProcessVmReadvSupported()) {
// The process_vm_readv path is about 50 times faster than ptrace api. We
// want to use this syscall if it is supported.
const ::pid_t pid = GetID();
struct iovec local_iov, remote_iov;
local_iov.iov_base = buf;
local_iov.iov_len = size;
remote_iov.iov_base = reinterpret_cast<void *>(addr);
remote_iov.iov_len = size;
bytes_read = process_vm_readv(pid, &local_iov, 1, &remote_iov, 1, 0);
const bool success = bytes_read == size;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
LLDB_LOG(log,
"using process_vm_readv to read {0} bytes from inferior "
"address {1:x}: {2}",
size, addr, success ? "Success" : llvm::sys::StrError(errno));
if (success)
return Status();
// else the call failed for some reason, let's retry the read using ptrace
// api.
}
unsigned char *dst = static_cast<unsigned char *>(buf);
size_t remainder;
long data;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_MEMORY));
LLDB_LOG(log, "addr = {0}, buf = {1}, size = {2}", addr, buf, size);
for (bytes_read = 0; bytes_read < size; bytes_read += remainder) {
Status error = NativeProcessLinux::PtraceWrapper(
PTRACE_PEEKDATA, GetID(), (void *)addr, nullptr, 0, &data);
if (error.Fail())
return error;
remainder = size - bytes_read;
remainder = remainder > k_ptrace_word_size ? k_ptrace_word_size : remainder;
// Copy the data into our buffer
memcpy(dst, &data, remainder);
LLDB_LOG(log, "[{0:x}]:{1:x}", addr, data);
addr += k_ptrace_word_size;
dst += k_ptrace_word_size;
}
return Status();
}
Status NativeProcessLinux::WriteMemory(lldb::addr_t addr, const void *buf,
size_t size, size_t &bytes_written) {
const unsigned char *src = static_cast<const unsigned char *>(buf);
size_t remainder;
Status error;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_MEMORY));
LLDB_LOG(log, "addr = {0}, buf = {1}, size = {2}", addr, buf, size);
for (bytes_written = 0; bytes_written < size; bytes_written += remainder) {
remainder = size - bytes_written;
remainder = remainder > k_ptrace_word_size ? k_ptrace_word_size : remainder;
if (remainder == k_ptrace_word_size) {
unsigned long data = 0;
memcpy(&data, src, k_ptrace_word_size);
LLDB_LOG(log, "[{0:x}]:{1:x}", addr, data);
error = NativeProcessLinux::PtraceWrapper(PTRACE_POKEDATA, GetID(),
(void *)addr, (void *)data);
if (error.Fail())
return error;
} else {
unsigned char buff[8];
size_t bytes_read;
error = ReadMemory(addr, buff, k_ptrace_word_size, bytes_read);
if (error.Fail())
return error;
memcpy(buff, src, remainder);
size_t bytes_written_rec;
error = WriteMemory(addr, buff, k_ptrace_word_size, bytes_written_rec);
if (error.Fail())
return error;
LLDB_LOG(log, "[{0:x}]:{1:x} ({2:x})", addr, *(const unsigned long *)src,
*(unsigned long *)buff);
}
addr += k_ptrace_word_size;
src += k_ptrace_word_size;
}
return error;
}
Status NativeProcessLinux::GetSignalInfo(lldb::tid_t tid, void *siginfo) {
return PtraceWrapper(PTRACE_GETSIGINFO, tid, nullptr, siginfo);
}
Status NativeProcessLinux::GetEventMessage(lldb::tid_t tid,
unsigned long *message) {
return PtraceWrapper(PTRACE_GETEVENTMSG, tid, nullptr, message);
}
Status NativeProcessLinux::Detach(lldb::tid_t tid) {
if (tid == LLDB_INVALID_THREAD_ID)
return Status();
return PtraceWrapper(PTRACE_DETACH, tid);
}
bool NativeProcessLinux::HasThreadNoLock(lldb::tid_t thread_id) {
for (const auto &thread : m_threads) {
assert(thread && "thread list should not contain NULL threads");
if (thread->GetID() == thread_id) {
// We have this thread.
return true;
}
}
// We don't have this thread.
return false;
}
bool NativeProcessLinux::StopTrackingThread(lldb::tid_t thread_id) {
Log *const log = ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD);
LLDB_LOG(log, "tid: {0})", thread_id);
bool found = false;
for (auto it = m_threads.begin(); it != m_threads.end(); ++it) {
if (*it && ((*it)->GetID() == thread_id)) {
m_threads.erase(it);
found = true;
break;
}
}
if (found)
StopTracingForThread(thread_id);
SignalIfAllThreadsStopped();
return found;
}
NativeThreadLinux &NativeProcessLinux::AddThread(lldb::tid_t thread_id) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD));
LLDB_LOG(log, "pid {0} adding thread with tid {1}", GetID(), thread_id);
assert(!HasThreadNoLock(thread_id) &&
"attempted to add a thread by id that already exists");
// If this is the first thread, save it as the current thread
if (m_threads.empty())
SetCurrentThreadID(thread_id);
m_threads.push_back(std::make_unique<NativeThreadLinux>(*this, thread_id));
if (m_pt_proces_trace_id != LLDB_INVALID_UID) {
auto traceMonitor = ProcessorTraceMonitor::Create(
GetID(), thread_id, m_pt_process_trace_config, true);
if (traceMonitor) {
m_pt_traced_thread_group.insert(thread_id);
m_processor_trace_monitor.insert(
std::make_pair(thread_id, std::move(*traceMonitor)));
} else {
LLDB_LOG(log, "failed to start trace on thread {0}", thread_id);
Status error(traceMonitor.takeError());
LLDB_LOG(log, "error {0}", error);
}
}
return static_cast<NativeThreadLinux &>(*m_threads.back());
}
Status NativeProcessLinux::GetLoadedModuleFileSpec(const char *module_path,
FileSpec &file_spec) {
Status error = PopulateMemoryRegionCache();
if (error.Fail())
return error;
FileSpec module_file_spec(module_path);
FileSystem::Instance().Resolve(module_file_spec);
file_spec.Clear();
for (const auto &it : m_mem_region_cache) {
if (it.second.GetFilename() == module_file_spec.GetFilename()) {
file_spec = it.second;
return Status();
}
}
return Status("Module file (%s) not found in /proc/%" PRIu64 "/maps file!",
module_file_spec.GetFilename().AsCString(), GetID());
}
Status NativeProcessLinux::GetFileLoadAddress(const llvm::StringRef &file_name,
lldb::addr_t &load_addr) {
load_addr = LLDB_INVALID_ADDRESS;
Status error = PopulateMemoryRegionCache();
if (error.Fail())
return error;
FileSpec file(file_name);
for (const auto &it : m_mem_region_cache) {
if (it.second == file) {
load_addr = it.first.GetRange().GetRangeBase();
return Status();
}
}
return Status("No load address found for specified file.");
}
NativeThreadLinux *NativeProcessLinux::GetThreadByID(lldb::tid_t tid) {
return static_cast<NativeThreadLinux *>(
NativeProcessProtocol::GetThreadByID(tid));
}
Status NativeProcessLinux::ResumeThread(NativeThreadLinux &thread,
lldb::StateType state, int signo) {
Log *const log = ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD);
LLDB_LOG(log, "tid: {0}", thread.GetID());
// Before we do the resume below, first check if we have a pending stop
// notification that is currently waiting for all threads to stop. This is
// potentially a buggy situation since we're ostensibly waiting for threads
// to stop before we send out the pending notification, and here we are
// resuming one before we send out the pending stop notification.
if (m_pending_notification_tid != LLDB_INVALID_THREAD_ID) {
LLDB_LOG(log,
"about to resume tid {0} per explicit request but we have a "
"pending stop notification (tid {1}) that is actively "
"waiting for this thread to stop. Valid sequence of events?",
thread.GetID(), m_pending_notification_tid);
}
// Request a resume. We expect this to be synchronous and the system to
// reflect it is running after this completes.
switch (state) {
case eStateRunning: {
const auto resume_result = thread.Resume(signo);
if (resume_result.Success())
SetState(eStateRunning, true);
return resume_result;
}
case eStateStepping: {
const auto step_result = thread.SingleStep(signo);
if (step_result.Success())
SetState(eStateRunning, true);
return step_result;
}
default:
LLDB_LOG(log, "Unhandled state {0}.", state);
llvm_unreachable("Unhandled state for resume");
}
}
//===----------------------------------------------------------------------===//
void NativeProcessLinux::StopRunningThreads(const lldb::tid_t triggering_tid) {
Log *const log = ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD);
LLDB_LOG(log, "about to process event: (triggering_tid: {0})",
triggering_tid);
m_pending_notification_tid = triggering_tid;
// Request a stop for all the thread stops that need to be stopped and are
// not already known to be stopped.
for (const auto &thread : m_threads) {
if (StateIsRunningState(thread->GetState()))
static_cast<NativeThreadLinux *>(thread.get())->RequestStop();
}
SignalIfAllThreadsStopped();
LLDB_LOG(log, "event processing done");
}
void NativeProcessLinux::SignalIfAllThreadsStopped() {
if (m_pending_notification_tid == LLDB_INVALID_THREAD_ID)
return; // No pending notification. Nothing to do.
for (const auto &thread_sp : m_threads) {
if (StateIsRunningState(thread_sp->GetState()))
return; // Some threads are still running. Don't signal yet.
}
// We have a pending notification and all threads have stopped.
Log *log(
GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS | LIBLLDB_LOG_BREAKPOINTS));
// Clear any temporary breakpoints we used to implement software single
// stepping.
for (const auto &thread_info : m_threads_stepping_with_breakpoint) {
Status error = RemoveBreakpoint(thread_info.second);
if (error.Fail())
LLDB_LOG(log, "pid = {0} remove stepping breakpoint: {1}",
thread_info.first, error);
}
m_threads_stepping_with_breakpoint.clear();
// Notify the delegate about the stop
SetCurrentThreadID(m_pending_notification_tid);
SetState(StateType::eStateStopped, true);
m_pending_notification_tid = LLDB_INVALID_THREAD_ID;
}
void NativeProcessLinux::ThreadWasCreated(NativeThreadLinux &thread) {
Log *const log = ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD);
LLDB_LOG(log, "tid: {0}", thread.GetID());
if (m_pending_notification_tid != LLDB_INVALID_THREAD_ID &&
StateIsRunningState(thread.GetState())) {
// We will need to wait for this new thread to stop as well before firing
// the notification.
thread.RequestStop();
}
}
void NativeProcessLinux::SigchldHandler() {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
// Process all pending waitpid notifications.
while (true) {
int status = -1;
::pid_t wait_pid = llvm::sys::RetryAfterSignal(-1, ::waitpid, -1, &status,
__WALL | __WNOTHREAD | WNOHANG);
if (wait_pid == 0)
break; // We are done.
if (wait_pid == -1) {
Status error(errno, eErrorTypePOSIX);
LLDB_LOG(log, "waitpid (-1, &status, _) failed: {0}", error);
break;
}
WaitStatus wait_status = WaitStatus::Decode(status);
bool exited = wait_status.type == WaitStatus::Exit ||
(wait_status.type == WaitStatus::Signal &&
wait_pid == static_cast<::pid_t>(GetID()));
LLDB_LOG(
log,
"waitpid (-1, &status, _) => pid = {0}, status = {1}, exited = {2}",
wait_pid, wait_status, exited);
MonitorCallback(wait_pid, exited, wait_status);
}
}
// Wrapper for ptrace to catch errors and log calls. Note that ptrace sets
// errno on error because -1 can be a valid result (i.e. for PTRACE_PEEK*)
Status NativeProcessLinux::PtraceWrapper(int req, lldb::pid_t pid, void *addr,
void *data, size_t data_size,
long *result) {
Status error;
long int ret;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
PtraceDisplayBytes(req, data, data_size);
errno = 0;
if (req == PTRACE_GETREGSET || req == PTRACE_SETREGSET)
ret = ptrace(static_cast<__ptrace_request>(req), static_cast<::pid_t>(pid),
*(unsigned int *)addr, data);
else
ret = ptrace(static_cast<__ptrace_request>(req), static_cast<::pid_t>(pid),
addr, data);
if (ret == -1)
error.SetErrorToErrno();
if (result)
*result = ret;
LLDB_LOG(log, "ptrace({0}, {1}, {2}, {3}, {4})={5:x}", req, pid, addr, data,
data_size, ret);
PtraceDisplayBytes(req, data, data_size);
if (error.Fail())
LLDB_LOG(log, "ptrace() failed: {0}", error);
return error;
}
llvm::Expected<ProcessorTraceMonitor &>
NativeProcessLinux::LookupProcessorTraceInstance(lldb::user_id_t traceid,
lldb::tid_t thread) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
if (thread == LLDB_INVALID_THREAD_ID && traceid == m_pt_proces_trace_id) {
LLDB_LOG(log, "thread not specified: {0}", traceid);
return Status("tracing not active thread not specified").ToError();
}
for (auto& iter : m_processor_trace_monitor) {
if (traceid == iter.second->GetTraceID() &&
(thread == iter.first || thread == LLDB_INVALID_THREAD_ID))
return *(iter.second);
}
LLDB_LOG(log, "traceid not being traced: {0}", traceid);
return Status("tracing not active for this thread").ToError();
}
Status NativeProcessLinux::GetMetaData(lldb::user_id_t traceid,
lldb::tid_t thread,
llvm::MutableArrayRef<uint8_t> &buffer,
size_t offset) {
TraceOptions trace_options;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
Status error;
LLDB_LOG(log, "traceid {0}", traceid);
auto perf_monitor = LookupProcessorTraceInstance(traceid, thread);
if (!perf_monitor) {
LLDB_LOG(log, "traceid not being traced: {0}", traceid);
buffer = buffer.slice(buffer.size());
error = perf_monitor.takeError();
return error;
}
return (*perf_monitor).ReadPerfTraceData(buffer, offset);
}
Status NativeProcessLinux::GetData(lldb::user_id_t traceid, lldb::tid_t thread,
llvm::MutableArrayRef<uint8_t> &buffer,
size_t offset) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
Status error;
LLDB_LOG(log, "traceid {0}", traceid);
auto perf_monitor = LookupProcessorTraceInstance(traceid, thread);
if (!perf_monitor) {
LLDB_LOG(log, "traceid not being traced: {0}", traceid);
buffer = buffer.slice(buffer.size());
error = perf_monitor.takeError();
return error;
}
return (*perf_monitor).ReadPerfTraceAux(buffer, offset);
}
Status NativeProcessLinux::GetTraceConfig(lldb::user_id_t traceid,
TraceOptions &config) {
Status error;
if (config.getThreadID() == LLDB_INVALID_THREAD_ID &&
m_pt_proces_trace_id == traceid) {
if (m_pt_proces_trace_id == LLDB_INVALID_UID) {
error.SetErrorString("tracing not active for this process");
return error;
}
config = m_pt_process_trace_config;
} else {
auto perf_monitor =
LookupProcessorTraceInstance(traceid, config.getThreadID());
if (!perf_monitor) {
error = perf_monitor.takeError();
return error;
}
error = (*perf_monitor).GetTraceConfig(config);
}
return error;
}
lldb::user_id_t
NativeProcessLinux::StartTraceGroup(const TraceOptions &config,
Status &error) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
if (config.getType() != TraceType::eTraceTypeProcessorTrace)
return LLDB_INVALID_UID;
if (m_pt_proces_trace_id != LLDB_INVALID_UID) {
error.SetErrorString("tracing already active on this process");
return m_pt_proces_trace_id;
}
for (const auto &thread_sp : m_threads) {
if (auto traceInstance = ProcessorTraceMonitor::Create(
GetID(), thread_sp->GetID(), config, true)) {
m_pt_traced_thread_group.insert(thread_sp->GetID());
m_processor_trace_monitor.insert(
std::make_pair(thread_sp->GetID(), std::move(*traceInstance)));
}
}
m_pt_process_trace_config = config;
error = ProcessorTraceMonitor::GetCPUType(m_pt_process_trace_config);
// Trace on Complete process will have traceid of 0
m_pt_proces_trace_id = 0;
LLDB_LOG(log, "Process Trace ID {0}", m_pt_proces_trace_id);
return m_pt_proces_trace_id;
}
lldb::user_id_t NativeProcessLinux::StartTrace(const TraceOptions &config,
Status &error) {
if (config.getType() != TraceType::eTraceTypeProcessorTrace)
return NativeProcessProtocol::StartTrace(config, error);
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
lldb::tid_t threadid = config.getThreadID();
if (threadid == LLDB_INVALID_THREAD_ID)
return StartTraceGroup(config, error);
auto thread_sp = GetThreadByID(threadid);
if (!thread_sp) {
// Thread not tracked by lldb so don't trace.
error.SetErrorString("invalid thread id");
return LLDB_INVALID_UID;
}
const auto &iter = m_processor_trace_monitor.find(threadid);
if (iter != m_processor_trace_monitor.end()) {
LLDB_LOG(log, "Thread already being traced");
error.SetErrorString("tracing already active on this thread");
return LLDB_INVALID_UID;
}
auto traceMonitor =
ProcessorTraceMonitor::Create(GetID(), threadid, config, false);
if (!traceMonitor) {
error = traceMonitor.takeError();
LLDB_LOG(log, "error {0}", error);
return LLDB_INVALID_UID;
}
lldb::user_id_t ret_trace_id = (*traceMonitor)->GetTraceID();
m_processor_trace_monitor.insert(
std::make_pair(threadid, std::move(*traceMonitor)));
return ret_trace_id;
}
Status NativeProcessLinux::StopTracingForThread(lldb::tid_t thread) {
Status error;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
LLDB_LOG(log, "Thread {0}", thread);
const auto& iter = m_processor_trace_monitor.find(thread);
if (iter == m_processor_trace_monitor.end()) {
error.SetErrorString("tracing not active for this thread");
return error;
}
if (iter->second->GetTraceID() == m_pt_proces_trace_id) {
// traceid maps to the whole process so we have to erase it from the thread
// group.
LLDB_LOG(log, "traceid maps to process");
m_pt_traced_thread_group.erase(thread);
}
m_processor_trace_monitor.erase(iter);
return error;
}
Status NativeProcessLinux::StopTrace(lldb::user_id_t traceid,
lldb::tid_t thread) {
Status error;
TraceOptions trace_options;
trace_options.setThreadID(thread);
error = NativeProcessLinux::GetTraceConfig(traceid, trace_options);
if (error.Fail())
return error;
switch (trace_options.getType()) {
case lldb::TraceType::eTraceTypeProcessorTrace:
if (traceid == m_pt_proces_trace_id &&
thread == LLDB_INVALID_THREAD_ID)
StopProcessorTracingOnProcess();
else
error = StopProcessorTracingOnThread(traceid, thread);
break;
default:
error.SetErrorString("trace not supported");
break;
}
return error;
}
void NativeProcessLinux::StopProcessorTracingOnProcess() {
for (auto thread_id_iter : m_pt_traced_thread_group)
m_processor_trace_monitor.erase(thread_id_iter);
m_pt_traced_thread_group.clear();
m_pt_proces_trace_id = LLDB_INVALID_UID;
}
Status NativeProcessLinux::StopProcessorTracingOnThread(lldb::user_id_t traceid,
lldb::tid_t thread) {
Status error;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
if (thread == LLDB_INVALID_THREAD_ID) {
for (auto& iter : m_processor_trace_monitor) {
if (iter.second->GetTraceID() == traceid) {
// Stopping a trace instance for an individual thread hence there will
// only be one traceid that can match.
m_processor_trace_monitor.erase(iter.first);
return error;
}
LLDB_LOG(log, "Trace ID {0}", iter.second->GetTraceID());
}
LLDB_LOG(log, "Invalid TraceID");
error.SetErrorString("invalid trace id");
return error;
}
// thread is specified so we can use find function on the map.
const auto& iter = m_processor_trace_monitor.find(thread);
if (iter == m_processor_trace_monitor.end()) {
// thread not found in our map.
LLDB_LOG(log, "thread not being traced");
error.SetErrorString("tracing not active for this thread");
return error;
}
if (iter->second->GetTraceID() != traceid) {
// traceid did not match so it has to be invalid.
LLDB_LOG(log, "Invalid TraceID");
error.SetErrorString("invalid trace id");
return error;
}
LLDB_LOG(log, "UID - {0} , Thread -{1}", traceid, thread);
if (traceid == m_pt_proces_trace_id) {
// traceid maps to the whole process so we have to erase it from the thread
// group.
LLDB_LOG(log, "traceid maps to process");
m_pt_traced_thread_group.erase(thread);
}
m_processor_trace_monitor.erase(iter);
return error;
}