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llvm-project/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
Pavel Labath 08c38f77c5 Revert "Implement xfer:libraries-svr4:read packet" 
D62502, together with D62503 have broken the builds which have XML
support enabled. Reverting D62503 (r364355) fixed that, but has broken
has left some of the tests introduced by D62502 broken more or less
nondeternimistically (it depended on whether the system happens to place
the library list near unreadable pages of memory). I attempted to make a
partial fix for this in r364748, but Jan Kratochvil pointed out that
this reintroduces the problem which reverting D62503 was trying to
solve.

So instead, I back out the whole thing so we can get back to a clean
slate that works for everyone. We can figure out a way forward from
there.

This reverts r364748, r363772 and r363707.

llvm-svn: 364751
2019-07-01 12:41:20 +00:00

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//===-- 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");
for (auto i = m_threads.begin(); i != m_threads.end();) {
if ((*i)->GetID() == GetID())
i = m_threads.erase(i);
else
++i;
}
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 &reg_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 &reg_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 &reg_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 &regsiter_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(llvm::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;
}
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