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llvm-project/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp

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//===-- NativeProcessLinux.cpp -------------------------------- -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "NativeProcessLinux.h"
// C Includes
#include <errno.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
// C++ Includes
#include <fstream>
#include <mutex>
#include <sstream>
#include <string>
#include <unordered_map>
// Other libraries and framework includes
#include "lldb/Core/EmulateInstruction.h"
#include "lldb/Core/Error.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/RegisterValue.h"
#include "lldb/Core/State.h"
#include "lldb/Host/Host.h"
#include "lldb/Host/HostProcess.h"
#include "lldb/Host/ThreadLauncher.h"
#include "lldb/Host/common/NativeBreakpoint.h"
#include "lldb/Host/common/NativeRegisterContext.h"
#include "lldb/Host/linux/ProcessLauncherLinux.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/ProcessLaunchInfo.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/Utility/PseudoTerminal.h"
#include "lldb/Utility/StringExtractor.h"
#include "NativeThreadLinux.h"
#include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
#include "ProcFileReader.h"
#include "Procfs.h"
// System includes - They have to be included after framework includes because
// they define some
// macros which collide with variable names in other modules
#include <linux/unistd.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/wait.h>
#include "lldb/Host/linux/Personality.h"
#include "lldb/Host/linux/Ptrace.h"
#include "lldb/Host/linux/Uio.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 std::once_flag flag;
std::call_once(flag, [] {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_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 (log) {
if (is_supported)
log->Printf("%s: Detected kernel support for process_vm_readv syscall. "
"Fast memory reads enabled.",
__FUNCTION__);
else
log->Printf("%s: syscall process_vm_readv failed (error: %s). Fast "
"memory reads disabled.",
__FUNCTION__, strerror(errno));
}
});
return is_supported;
}
namespace {
void MaybeLogLaunchInfo(const ProcessLaunchInfo &info) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
if (!log)
return;
if (const FileAction *action = info.GetFileActionForFD(STDIN_FILENO))
log->Printf("%s: setting STDIN to '%s'", __FUNCTION__,
action->GetFileSpec().GetCString());
else
log->Printf("%s leaving STDIN as is", __FUNCTION__);
if (const FileAction *action = info.GetFileActionForFD(STDOUT_FILENO))
log->Printf("%s setting STDOUT to '%s'", __FUNCTION__,
action->GetFileSpec().GetCString());
else
log->Printf("%s leaving STDOUT as is", __FUNCTION__);
if (const FileAction *action = info.GetFileActionForFD(STDERR_FILENO))
log->Printf("%s setting STDERR to '%s'", __FUNCTION__,
action->GetFileSpec().GetCString());
else
log->Printf("%s leaving STDERR as is", __FUNCTION__);
int i = 0;
for (const char **args = info.GetArguments().GetConstArgumentVector(); *args;
++args, ++i)
log->Printf("%s arg %d: \"%s\"", __FUNCTION__, i,
*args ? *args : "nullptr");
}
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) {
StreamString buf;
Log *verbose_log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(
POSIX_LOG_PTRACE | POSIX_LOG_VERBOSE));
if (verbose_log) {
switch (req) {
case PTRACE_POKETEXT: {
DisplayBytes(buf, &data, 8);
verbose_log->Printf("PTRACE_POKETEXT %s", buf.GetData());
break;
}
case PTRACE_POKEDATA: {
DisplayBytes(buf, &data, 8);
verbose_log->Printf("PTRACE_POKEDATA %s", buf.GetData());
break;
}
case PTRACE_POKEUSER: {
DisplayBytes(buf, &data, 8);
verbose_log->Printf("PTRACE_POKEUSER %s", buf.GetData());
break;
}
case PTRACE_SETREGS: {
DisplayBytes(buf, data, data_size);
verbose_log->Printf("PTRACE_SETREGS %s", buf.GetData());
break;
}
case PTRACE_SETFPREGS: {
DisplayBytes(buf, data, data_size);
verbose_log->Printf("PTRACE_SETFPREGS %s", buf.GetData());
break;
}
case PTRACE_SETSIGINFO: {
DisplayBytes(buf, data, sizeof(siginfo_t));
verbose_log->Printf("PTRACE_SETSIGINFO %s", 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);
verbose_log->Printf("PTRACE_SETREGSET %s", 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 Error EnsureFDFlags(int fd, int flags) {
Error 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
// -----------------------------------------------------------------------------
Error NativeProcessProtocol::Launch(
ProcessLaunchInfo &launch_info,
NativeProcessProtocol::NativeDelegate &native_delegate, MainLoop &mainloop,
NativeProcessProtocolSP &native_process_sp) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
Error error;
// Verify the working directory is valid if one was specified.
FileSpec working_dir{launch_info.GetWorkingDirectory()};
if (working_dir &&
(!working_dir.ResolvePath() ||
working_dir.GetFileType() != FileSpec::eFileTypeDirectory)) {
error.SetErrorStringWithFormat("No such file or directory: %s",
working_dir.GetCString());
return error;
}
// Create the NativeProcessLinux in launch mode.
native_process_sp.reset(new NativeProcessLinux());
if (!native_process_sp->RegisterNativeDelegate(native_delegate)) {
native_process_sp.reset();
error.SetErrorStringWithFormat("failed to register the native delegate");
return error;
}
error = std::static_pointer_cast<NativeProcessLinux>(native_process_sp)
->LaunchInferior(mainloop, launch_info);
if (error.Fail()) {
native_process_sp.reset();
if (log)
log->Printf("NativeProcessLinux::%s failed to launch process: %s",
__FUNCTION__, error.AsCString());
return error;
}
launch_info.SetProcessID(native_process_sp->GetID());
return error;
}
Error NativeProcessProtocol::Attach(
lldb::pid_t pid, NativeProcessProtocol::NativeDelegate &native_delegate,
MainLoop &mainloop, NativeProcessProtocolSP &native_process_sp) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
if (log && log->GetMask().Test(POSIX_LOG_VERBOSE))
log->Printf("NativeProcessLinux::%s(pid = %" PRIi64 ")", __FUNCTION__, pid);
// Retrieve the architecture for the running process.
ArchSpec process_arch;
Error error = ResolveProcessArchitecture(pid, process_arch);
if (!error.Success())
return error;
std::shared_ptr<NativeProcessLinux> native_process_linux_sp(
new NativeProcessLinux());
if (!native_process_linux_sp->RegisterNativeDelegate(native_delegate)) {
error.SetErrorStringWithFormat("failed to register the native delegate");
return error;
}
native_process_linux_sp->AttachToInferior(mainloop, pid, error);
if (!error.Success())
return error;
native_process_sp = native_process_linux_sp;
return error;
}
// -----------------------------------------------------------------------------
// Public Instance Methods
// -----------------------------------------------------------------------------
NativeProcessLinux::NativeProcessLinux()
: NativeProcessProtocol(LLDB_INVALID_PROCESS_ID), m_arch(),
m_supports_mem_region(eLazyBoolCalculate), m_mem_region_cache(),
m_pending_notification_tid(LLDB_INVALID_THREAD_ID) {}
void NativeProcessLinux::AttachToInferior(MainLoop &mainloop, lldb::pid_t pid,
Error &error) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
if (log)
log->Printf("NativeProcessLinux::%s (pid = %" PRIi64 ")", __FUNCTION__,
pid);
m_sigchld_handle = mainloop.RegisterSignal(
SIGCHLD, [this](MainLoopBase &) { SigchldHandler(); }, error);
if (!m_sigchld_handle)
return;
error = ResolveProcessArchitecture(pid, m_arch);
if (!error.Success())
return;
// Set the architecture to the exe architecture.
if (log)
log->Printf("NativeProcessLinux::%s (pid = %" PRIi64
") detected architecture %s",
__FUNCTION__, pid, m_arch.GetArchitectureName());
m_pid = pid;
SetState(eStateAttaching);
Attach(pid, error);
}
Error NativeProcessLinux::LaunchInferior(MainLoop &mainloop,
ProcessLaunchInfo &launch_info) {
Error error;
m_sigchld_handle = mainloop.RegisterSignal(
SIGCHLD, [this](MainLoopBase &) { SigchldHandler(); }, error);
if (!m_sigchld_handle)
return error;
SetState(eStateLaunching);
MaybeLogLaunchInfo(launch_info);
::pid_t pid =
ProcessLauncherLinux().LaunchProcess(launch_info, error).GetProcessId();
if (error.Fail())
return error;
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
// Wait for the child process to trap on its call to execve.
::pid_t wpid;
int status;
if ((wpid = waitpid(pid, &status, 0)) < 0) {
error.SetErrorToErrno();
if (log)
log->Printf("NativeProcessLinux::%s waitpid for inferior failed with %s",
__FUNCTION__, error.AsCString());
// Mark the inferior as invalid.
// FIXME this could really use a new state - eStateLaunchFailure. For now,
// using eStateInvalid.
SetState(StateType::eStateInvalid);
return error;
}
assert(WIFSTOPPED(status) && (wpid == static_cast<::pid_t>(pid)) &&
"Could not sync with inferior process.");
if (log)
log->Printf("NativeProcessLinux::%s inferior started, now in stopped state",
__FUNCTION__);
error = SetDefaultPtraceOpts(pid);
if (error.Fail()) {
if (log)
log->Printf("NativeProcessLinux::%s inferior failed to set default "
"ptrace options: %s",
__FUNCTION__, error.AsCString());
// Mark the inferior as invalid.
// FIXME this could really use a new state - eStateLaunchFailure. For now,
// using eStateInvalid.
SetState(StateType::eStateInvalid);
return error;
}
// Release the master terminal descriptor and pass it off to the
// NativeProcessLinux instance. Similarly stash the inferior pid.
m_terminal_fd = launch_info.GetPTY().ReleaseMasterFileDescriptor();
m_pid = pid;
launch_info.SetProcessID(pid);
if (m_terminal_fd != -1) {
error = EnsureFDFlags(m_terminal_fd, O_NONBLOCK);
if (error.Fail()) {
if (log)
log->Printf("NativeProcessLinux::%s inferior EnsureFDFlags failed for "
"ensuring terminal O_NONBLOCK setting: %s",
__FUNCTION__, error.AsCString());
// Mark the inferior as invalid.
// FIXME this could really use a new state - eStateLaunchFailure. For
// now, using eStateInvalid.
SetState(StateType::eStateInvalid);
return error;
}
}
if (log)
log->Printf("NativeProcessLinux::%s() adding pid = %" PRIu64, __FUNCTION__,
uint64_t(pid));
ResolveProcessArchitecture(m_pid, m_arch);
NativeThreadLinuxSP thread_sp = AddThread(pid);
assert(thread_sp && "AddThread() returned a nullptr thread");
thread_sp->SetStoppedBySignal(SIGSTOP);
ThreadWasCreated(*thread_sp);
// Let our process instance know the thread has stopped.
SetCurrentThreadID(thread_sp->GetID());
SetState(StateType::eStateStopped);
if (log) {
if (error.Success())
log->Printf("NativeProcessLinux::%s inferior launching succeeded",
__FUNCTION__);
else
log->Printf("NativeProcessLinux::%s inferior launching failed: %s",
__FUNCTION__, error.AsCString());
}
return error;
}
::pid_t NativeProcessLinux::Attach(lldb::pid_t pid, Error &error) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
// Use a map to keep track of the threads which we have attached/need to
// attach.
Host::TidMap tids_to_attach;
if (pid <= 1) {
error.SetErrorToGenericError();
error.SetErrorString("Attaching to process 1 is not allowed.");
return -1;
}
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.
error = PtraceWrapper(PTRACE_ATTACH, tid);
if (error.Fail()) {
// No such thread. The thread may have exited.
// More error handling may be needed.
if (error.GetError() == ESRCH) {
it = tids_to_attach.erase(it);
continue;
} else
return -1;
}
int status;
// 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 ((status = waitpid(tid, NULL, __WALL)) < 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;
} else {
error.SetErrorToErrno();
return -1;
}
}
error = SetDefaultPtraceOpts(tid);
if (error.Fail())
return -1;
if (log)
log->Printf("NativeProcessLinux::%s() adding tid = %" PRIu64,
__FUNCTION__, tid);
it->second = true;
// Create the thread, mark it as stopped.
NativeThreadLinuxSP thread_sp(AddThread(static_cast<lldb::tid_t>(tid)));
assert(thread_sp && "AddThread() returned a nullptr");
// This will notify this is a new thread and tell the system it is
// stopped.
thread_sp->SetStoppedBySignal(SIGSTOP);
ThreadWasCreated(*thread_sp);
SetCurrentThreadID(thread_sp->GetID());
}
// move the loop forward
++it;
}
}
if (tids_to_attach.size() > 0) {
m_pid = pid;
// Let our process instance know the thread has stopped.
SetState(StateType::eStateStopped);
} else {
error.SetErrorToGenericError();
error.SetErrorString("No such process.");
return -1;
}
return pid;
}
Error 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);
}
static ExitType convert_pid_status_to_exit_type(int status) {
if (WIFEXITED(status))
return ExitType::eExitTypeExit;
else if (WIFSIGNALED(status))
return ExitType::eExitTypeSignal;
else if (WIFSTOPPED(status))
return ExitType::eExitTypeStop;
else {
// We don't know what this is.
return ExitType::eExitTypeInvalid;
}
}
static int convert_pid_status_to_return_code(int status) {
if (WIFEXITED(status))
return WEXITSTATUS(status);
else if (WIFSIGNALED(status))
return WTERMSIG(status);
else if (WIFSTOPPED(status))
return WSTOPSIG(status);
else {
// We don't know what this is.
return ExitType::eExitTypeInvalid;
}
}
// Handles all waitpid events from the inferior process.
void NativeProcessLinux::MonitorCallback(lldb::pid_t pid, bool exited,
int signal, int 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) {
if (log)
log->Printf(
"NativeProcessLinux::%s() got exit signal(%d) , tid = %" PRIu64
" (%s main thread)",
__FUNCTION__, signal, pid, is_main_thread ? "is" : "is not");
// This is a thread that exited. Ensure we're not tracking it anymore.
const bool thread_found = StopTrackingThread(pid);
if (is_main_thread) {
// We only set the exit status and notify the delegate if we haven't
// already set the process
// state to an exited state. We normally should have received a SIGTRAP |
// (PTRACE_EVENT_EXIT << 8)
// for the main thread.
const bool already_notified = (GetState() == StateType::eStateExited) ||
(GetState() == StateType::eStateCrashed);
if (!already_notified) {
if (log)
log->Printf("NativeProcessLinux::%s() tid = %" PRIu64
" handling main thread exit (%s), expected exit state "
"already set but state was %s instead, setting exit "
"state now",
__FUNCTION__, pid,
thread_found ? "stopped tracking thread metadata"
: "thread metadata not found",
StateAsCString(GetState()));
// The main thread exited. We're done monitoring. Report to delegate.
SetExitStatus(convert_pid_status_to_exit_type(status),
convert_pid_status_to_return_code(status), nullptr, true);
// Notify delegate that our process has exited.
SetState(StateType::eStateExited, true);
} else {
if (log)
log->Printf("NativeProcessLinux::%s() tid = %" PRIu64
" main thread now exited (%s)",
__FUNCTION__, pid,
thread_found ? "stopped tracking thread metadata"
: "thread metadata not found");
}
} else {
// Do we want to report to the delegate in this case? I think not. If
// this was an orderly
// thread exit, we would already have received the SIGTRAP |
// (PTRACE_EVENT_EXIT << 8) signal,
// and we would have done an all-stop then.
if (log)
log->Printf("NativeProcessLinux::%s() tid = %" PRIu64
" handling non-main thread exit (%s)",
__FUNCTION__, pid,
thread_found ? "stopped tracking thread metadata"
: "thread metadata not found");
}
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
if (log)
log->Printf("NativeProcessLinux::%s received notification about an "
"unknown tid %" PRIu64 ".",
__FUNCTION__, pid);
if (info_err.Fail()) {
if (log)
log->Printf("NativeProcessLinux::%s (tid %" PRIu64
") GetSignalInfo failed (%s). Ingoring this notification.",
__FUNCTION__, pid, info_err.AsCString());
return;
}
if (log && (info.si_code != SI_USER || info.si_pid != 0))
log->Printf("NativeProcessLinux::%s (tid %" PRIu64
") unexpected signal info (si_code: %d, si_pid: %d). "
"Treating as a new thread notification anyway.",
__FUNCTION__, pid, info.si_code, info.si_pid);
auto thread_sp = AddThread(pid);
// Resume the newly created thread.
ResumeThread(*thread_sp, eStateRunning, LLDB_INVALID_SIGNAL_NUMBER);
ThreadWasCreated(*thread_sp);
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.
if (log)
log->Printf(
"NativeProcessLinux::%s received a group stop for pid %" PRIu64
" tid %" PRIu64 ". Transparent handling of group stops not "
"supported, resuming the thread.",
__FUNCTION__, 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);
if (log)
log->Printf(
"NativeProcessLinux::%s GetSignalInfo failed: %s, tid = %" PRIu64
", signal = %d, status = %d (%s, %s, %s)",
__FUNCTION__, info_err.AsCString(), pid, signal, status,
info_err.GetError() == ESRCH ? "thread/process killed"
: "unknown reason",
is_main_thread ? "is main thread" : "is not main thread",
thread_found ? "thread metadata removed"
: "thread metadata not 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(convert_pid_status_to_exit_type(status),
convert_pid_status_to_return_code(status), nullptr, 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?
if (log)
log->Printf("NativeProcessLinux::%s pid %" PRIu64 " tid %" PRIu64
" non-main thread exit occurred, didn't tell delegate "
"anything since thread disappeared out from underneath "
"us",
__FUNCTION__, GetID(), pid);
}
}
}
}
void NativeProcessLinux::WaitForNewThread(::pid_t tid) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
NativeThreadLinuxSP new_thread_sp = GetThreadByID(tid);
if (new_thread_sp) {
// 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;
::pid_t wait_pid;
do {
if (log)
log->Printf("NativeProcessLinux::%s() received thread creation event for "
"tid %" PRIu32
". tid not tracked yet, waiting for thread to appear...",
__FUNCTION__, tid);
wait_pid = waitpid(tid, &status, __WALL);
} while (wait_pid == -1 && errno == EINTR);
// 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) {
if (log)
log->Printf(
"NativeProcessLinux::%s() waiting for tid %" PRIu32
" failed. Assuming the thread has disappeared in the meantime",
__FUNCTION__, 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)) {
if (log)
log->Printf("NativeProcessLinux::%s() waiting for tid %" PRIu32
" returned an 'exited' event. Not tracking the thread.",
__FUNCTION__, tid);
// Also a very improbable event.
return;
}
siginfo_t info;
Error error = GetSignalInfo(tid, &info);
if (error.Fail()) {
if (log)
log->Printf(
"NativeProcessLinux::%s() GetSignalInfo for tid %" PRIu32
" failed. Assuming the thread has disappeared in the meantime.",
__FUNCTION__, tid);
return;
}
if (((info.si_pid != 0) || (info.si_code != SI_USER)) && log) {
// We should be getting a thread creation signal here, but we received
// something
// else. There isn't much we can do about it now, so we will just log that.
// Since the
// thread is alive and we are receiving events from it, we shall pretend
// that it was
// created properly.
log->Printf("NativeProcessLinux::%s() GetSignalInfo for tid %" PRIu32
" received unexpected signal with code %d from pid %d.",
__FUNCTION__, tid, info.si_code, info.si_pid);
}
if (log)
log->Printf("NativeProcessLinux::%s() pid = %" PRIu64
": tracking new thread tid %" PRIu32,
__FUNCTION__, GetID(), tid);
new_thread_sp = AddThread(tid);
ResumeThread(*new_thread_sp, eStateRunning, LLDB_INVALID_SIGNAL_NUMBER);
ThreadWasCreated(*new_thread_sp);
}
void NativeProcessLinux::MonitorSIGTRAP(const siginfo_t &info,
NativeThreadLinux &thread) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_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()) {
if (log)
log->Printf("NativeProcessLinux::%s() pid %" PRIu64
" received thread creation event but GetEventMessage "
"failed so we don't know the new tid",
__FUNCTION__, thread.GetID());
} else
WaitForNewThread(event_message);
ResumeThread(thread, thread.GetState(), LLDB_INVALID_SIGNAL_NUMBER);
break;
}
case (SIGTRAP | (PTRACE_EVENT_EXEC << 8)): {
NativeThreadLinuxSP main_thread_sp;
if (log)
log->Printf("NativeProcessLinux::%s() received exec event, code = %d",
__FUNCTION__, 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.
if (log)
log->Printf("NativeProcessLinux::%s exec received, stop tracking all but "
"main thread",
__FUNCTION__);
for (auto thread_sp : m_threads) {
const bool is_main_thread = thread_sp && thread_sp->GetID() == GetID();
if (is_main_thread) {
main_thread_sp = std::static_pointer_cast<NativeThreadLinux>(thread_sp);
if (log)
log->Printf(
"NativeProcessLinux::%s found main thread with tid %" PRIu64
", keeping",
__FUNCTION__, main_thread_sp->GetID());
} else {
if (log)
log->Printf(
"NativeProcessLinux::%s discarding non-main-thread tid %" PRIu64
" due to exec",
__FUNCTION__, thread_sp->GetID());
}
}
m_threads.clear();
if (main_thread_sp) {
m_threads.push_back(main_thread_sp);
SetCurrentThreadID(main_thread_sp->GetID());
main_thread_sp->SetStoppedByExec();
} else {
SetCurrentThreadID(LLDB_INVALID_THREAD_ID);
if (log)
log->Printf("NativeProcessLinux::%s pid %" PRIu64
"no main thread found, discarded all threads, we're in a "
"no-thread state!",
__FUNCTION__, GetID());
}
// Tell coordinator about about the "new" (since exec) stopped main thread.
ThreadWasCreated(*main_thread_sp);
// Let our delegate know we have just exec'd.
NotifyDidExec();
// If we have a main thread, indicate we are stopped.
assert(main_thread_sp && "exec called during ptraced process but no main "
"thread metadata tracked");
// Let the process know we're stopped.
StopRunningThreads(main_thread_sp->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;
if (log) {
log->Printf("NativeProcessLinux::%s() received PTRACE_EVENT_EXIT, data = "
"%lx (WIFEXITED=%s,WIFSIGNALED=%s), pid = %" PRIu64 " (%s)",
__FUNCTION__, data, WIFEXITED(data) ? "true" : "false",
WIFSIGNALED(data) ? "true" : "false", thread.GetID(),
is_main_thread ? "is main thread" : "not main thread");
}
if (is_main_thread) {
SetExitStatus(convert_pid_status_to_exit_type(data),
convert_pid_status_to_return_code(data), nullptr, true);
}
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;
Error error = thread.GetRegisterContext()->GetWatchpointHitIndex(
wp_index, (uintptr_t)info.si_addr);
if (error.Fail() && log)
log->Printf("NativeProcessLinux::%s() "
"received error while checking for watchpoint hits, "
"pid = %" PRIu64 " error = %s",
__FUNCTION__, thread.GetID(), error.AsCString());
if (wp_index != LLDB_INVALID_INDEX32) {
MonitorWatchpoint(thread, wp_index);
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;
Error error = thread.GetRegisterContext()->GetWatchpointHitIndex(
wp_index, LLDB_INVALID_ADDRESS);
if (error.Fail() && log)
log->Printf("NativeProcessLinux::%s() "
"received error while checking for watchpoint hits, "
"pid = %" PRIu64 " error = %s",
__FUNCTION__, thread.GetID(), error.AsCString());
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):
if (log)
log->Printf("NativeProcessLinux::%s() received unknown SIGTRAP system "
"call stop event, pid %" PRIu64 "tid %" PRIu64 ", resuming",
__FUNCTION__, GetID(), thread.GetID());
// Ignore these signals until we know more about them.
ResumeThread(thread, thread.GetState(), LLDB_INVALID_SIGNAL_NUMBER);
break;
default:
assert(false && "Unexpected SIGTRAP code!");
if (log)
log->Printf("NativeProcessLinux::%s() pid %" PRIu64 "tid %" PRIu64
" received unhandled SIGTRAP code: 0x%d",
__FUNCTION__, GetID(), thread.GetID(), info.si_code);
break;
}
}
void NativeProcessLinux::MonitorTrace(NativeThreadLinux &thread) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
if (log)
log->Printf("NativeProcessLinux::%s() received trace event, pid = %" PRIu64
" (single stepping)",
__FUNCTION__, 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));
if (log)
log->Printf(
"NativeProcessLinux::%s() received breakpoint event, pid = %" PRIu64,
__FUNCTION__, thread.GetID());
// Mark the thread as stopped at breakpoint.
thread.SetStoppedByBreakpoint();
Error error = FixupBreakpointPCAsNeeded(thread);
if (error.Fail())
if (log)
log->Printf("NativeProcessLinux::%s() pid = %" PRIu64 " fixup: %s",
__FUNCTION__, thread.GetID(), error.AsCString());
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));
if (log)
log->Printf("NativeProcessLinux::%s() received watchpoint event, "
"pid = %" PRIu64 ", wp_index = %" PRIu32,
__FUNCTION__, 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(GetLogIfAllCategoriesSet(LIBLLDB_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.
if (info.si_code == SI_TKILL || info.si_code == SI_USER) {
if (log)
log->Printf("NativeProcessLinux::%s() received signal %s (%d) with code "
"%s, (siginfo pid = %d (%s), waitpid pid = %" PRIu64 ")",
__FUNCTION__, Host::GetSignalAsCString(signo), signo,
(info.si_code == SI_TKILL ? "SI_TKILL" : "SI_USER"),
info.si_pid, is_from_llgs ? "from llgs" : "not from llgs",
thread.GetID());
}
// Check for thread stop notification.
if (is_from_llgs && (info.si_code == SI_TKILL) && (signo == SIGSTOP)) {
// This is a tgkill()-based stop.
if (log)
log->Printf("NativeProcessLinux::%s() pid %" PRIu64 " tid %" PRIu64
", thread stopped",
__FUNCTION__, 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.
Error error = ResumeThread(thread, thread.GetState(), 0);
if (error.Fail() && log) {
log->Printf(
"NativeProcessLinux::%s failed to resume thread tid %" PRIu64
": %s",
__FUNCTION__, thread.GetID(), error.AsCString());
}
}
} else {
if (log) {
// Retrieve the signal name if the thread was stopped by a signal.
int stop_signo = 0;
const bool stopped_by_signal = thread.IsStopped(&stop_signo);
const char *signal_name = stopped_by_signal
? Host::GetSignalAsCString(stop_signo)
: "<not stopped by signal>";
if (!signal_name)
signal_name = "<no-signal-name>";
log->Printf("NativeProcessLinux::%s() pid %" PRIu64 " tid %" PRIu64
", thread was already marked as a stopped state (state=%s, "
"signal=%d (%s)), leaving stop signal as is",
__FUNCTION__, GetID(), thread.GetID(),
StateAsCString(thread_state), stop_signo, signal_name);
}
SignalIfAllThreadsStopped();
}
// Done handling.
return;
}
if (log)
log->Printf("NativeProcessLinux::%s() received signal %s", __FUNCTION__,
Host::GetSignalAsCString(signo));
// This thread is stopped.
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]);
Error 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);
}
Error NativeProcessLinux::SetupSoftwareSingleStepping(
NativeThreadLinux &thread) {
Error error;
NativeRegisterContextSP register_context_sp = thread.GetRegisterContext();
std::unique_ptr<EmulateInstruction> emulator_ap(
EmulateInstruction::FindPlugin(m_arch, eInstructionTypePCModifying,
nullptr));
if (emulator_ap == nullptr)
return Error("Instruction emulator not found!");
EmulatorBaton baton(this, register_context_sp.get());
emulator_ap->SetBaton(&baton);
emulator_ap->SetReadMemCallback(&ReadMemoryCallback);
emulator_ap->SetReadRegCallback(&ReadRegisterCallback);
emulator_ap->SetWriteMemCallback(&WriteMemoryCallback);
emulator_ap->SetWriteRegCallback(&WriteRegisterCallback);
if (!emulator_ap->ReadInstruction())
return Error("Read instruction failed!");
bool emulation_result =
emulator_ap->EvaluateInstruction(eEmulateInstructionOptionAutoAdvancePC);
const RegisterInfo *reg_info_pc = register_context_sp->GetRegisterInfo(
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
const RegisterInfo *reg_info_flags = register_context_sp->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_sp.get());
} 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_sp->GetPC() + emulator_ap->GetOpcode().GetByteSize();
next_flags = ReadFlags(register_context_sp.get());
} 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 Error("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.GetMachine() == llvm::Triple::mips64 ||
m_arch.GetMachine() == llvm::Triple::mips64el ||
m_arch.GetMachine() == llvm::Triple::mips ||
m_arch.GetMachine() == llvm::Triple::mipsel)
error = SetSoftwareBreakpoint(next_pc, 4);
else {
// No size hint is given for the next breakpoint
error = SetSoftwareBreakpoint(next_pc, 0);
}
if (error.Fail())
return error;
m_threads_stepping_with_breakpoint.insert({thread.GetID(), next_pc});
return Error();
}
bool NativeProcessLinux::SupportHardwareSingleStepping() const {
if (m_arch.GetMachine() == llvm::Triple::arm ||
m_arch.GetMachine() == llvm::Triple::mips64 ||
m_arch.GetMachine() == llvm::Triple::mips64el ||
m_arch.GetMachine() == llvm::Triple::mips ||
m_arch.GetMachine() == llvm::Triple::mipsel)
return false;
return true;
}
Error NativeProcessLinux::Resume(const ResumeActionList &resume_actions) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS | LIBLLDB_LOG_THREAD));
if (log)
log->Printf("NativeProcessLinux::%s called: pid %" PRIu64, __FUNCTION__,
GetID());
bool software_single_step = !SupportHardwareSingleStepping();
if (software_single_step) {
for (auto thread_sp : m_threads) {
assert(thread_sp && "thread list should not contain NULL threads");
const ResumeAction *const action =
resume_actions.GetActionForThread(thread_sp->GetID(), true);
if (action == nullptr)
continue;
if (action->state == eStateStepping) {
Error error = SetupSoftwareSingleStepping(
static_cast<NativeThreadLinux &>(*thread_sp));
if (error.Fail())
return error;
}
}
}
for (auto thread_sp : m_threads) {
assert(thread_sp && "thread list should not contain NULL threads");
const ResumeAction *const action =
resume_actions.GetActionForThread(thread_sp->GetID(), true);
if (action == nullptr) {
if (log)
log->Printf(
"NativeProcessLinux::%s no action specified for pid %" PRIu64
" tid %" PRIu64,
__FUNCTION__, GetID(), thread_sp->GetID());
continue;
}
if (log) {
log->Printf("NativeProcessLinux::%s processing resume action state %s "
"for pid %" PRIu64 " tid %" PRIu64,
__FUNCTION__, StateAsCString(action->state), GetID(),
thread_sp->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_sp), action->state,
signo);
break;
}
case eStateSuspended:
case eStateStopped:
lldbassert(0 && "Unexpected state");
default:
return Error("NativeProcessLinux::%s (): unexpected state %s specified "
"for pid %" PRIu64 ", tid %" PRIu64,
__FUNCTION__, StateAsCString(action->state), GetID(),
thread_sp->GetID());
}
}
return Error();
}
Error NativeProcessLinux::Halt() {
Error error;
if (kill(GetID(), SIGSTOP) != 0)
error.SetErrorToErrno();
return error;
}
Error NativeProcessLinux::Detach() {
Error 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 (auto thread_sp : m_threads) {
Error e = Detach(thread_sp->GetID());
if (e.Fail())
error =
e; // Save the error, but still attempt to detach from other threads.
}
return error;
}
Error NativeProcessLinux::Signal(int signo) {
Error error;
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
if (log)
log->Printf(
"NativeProcessLinux::%s: sending signal %d (%s) to pid %" PRIu64,
__FUNCTION__, signo, Host::GetSignalAsCString(signo), GetID());
if (kill(GetID(), signo))
error.SetErrorToErrno();
return error;
}
Error 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(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
NativeThreadProtocolSP running_thread_sp;
NativeThreadProtocolSP stopped_thread_sp;
if (log)
log->Printf(
"NativeProcessLinux::%s selecting running thread for interrupt target",
__FUNCTION__);
for (auto thread_sp : m_threads) {
// The thread shouldn't be null but lets just cover that here.
if (!thread_sp)
continue;
// If we have a running or stepping thread, we'll call that the
// target of the interrupt.
const auto thread_state = thread_sp->GetState();
if (thread_state == eStateRunning || thread_state == eStateStepping) {
running_thread_sp = thread_sp;
break;
} else if (!stopped_thread_sp && 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_sp = thread_sp;
}
}
if (!running_thread_sp && !stopped_thread_sp) {
Error error("found no running/stepping or live stopped threads as target "
"for interrupt");
if (log)
log->Printf("NativeProcessLinux::%s skipping due to error: %s",
__FUNCTION__, error.AsCString());
return error;
}
NativeThreadProtocolSP deferred_signal_thread_sp =
running_thread_sp ? running_thread_sp : stopped_thread_sp;
if (log)
log->Printf("NativeProcessLinux::%s pid %" PRIu64 " %s tid %" PRIu64
" chosen for interrupt target",
__FUNCTION__, GetID(),
running_thread_sp ? "running" : "stopped",
deferred_signal_thread_sp->GetID());
StopRunningThreads(deferred_signal_thread_sp->GetID());
return Error();
}
Error NativeProcessLinux::Kill() {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
if (log)
log->Printf("NativeProcessLinux::%s called for PID %" PRIu64, __FUNCTION__,
GetID());
Error 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.
if (log)
log->Printf("NativeProcessLinux::%s ignored for PID %" PRIu64
" due to current state: %s",
__FUNCTION__, GetID(), StateAsCString(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;
}
static Error
ParseMemoryRegionInfoFromProcMapsLine(const std::string &maps_line,
MemoryRegionInfo &memory_region_info) {
memory_region_info.Clear();
StringExtractor line_extractor(maps_line.c_str());
// Format: {address_start_hex}-{address_end_hex} perms offset dev inode
// pathname
// perms: rwxp (letter is present if set, '-' if not, final character is
// p=private, s=shared).
// Parse out the starting address
lldb::addr_t start_address = line_extractor.GetHexMaxU64(false, 0);
// Parse out hyphen separating start and end address from range.
if (!line_extractor.GetBytesLeft() || (line_extractor.GetChar() != '-'))
return Error(
"malformed /proc/{pid}/maps entry, missing dash between address range");
// Parse out the ending address
lldb::addr_t end_address = line_extractor.GetHexMaxU64(false, start_address);
// Parse out the space after the address.
if (!line_extractor.GetBytesLeft() || (line_extractor.GetChar() != ' '))
return Error("malformed /proc/{pid}/maps entry, missing space after range");
// Save the range.
memory_region_info.GetRange().SetRangeBase(start_address);
memory_region_info.GetRange().SetRangeEnd(end_address);
// Any memory region in /proc/{pid}/maps is by definition mapped into the
// process.
memory_region_info.SetMapped(MemoryRegionInfo::OptionalBool::eYes);
// Parse out each permission entry.
if (line_extractor.GetBytesLeft() < 4)
return Error("malformed /proc/{pid}/maps entry, missing some portion of "
"permissions");
// Handle read permission.
const char read_perm_char = line_extractor.GetChar();
if (read_perm_char == 'r')
memory_region_info.SetReadable(MemoryRegionInfo::OptionalBool::eYes);
else if (read_perm_char == '-')
memory_region_info.SetReadable(MemoryRegionInfo::OptionalBool::eNo);
else
return Error("unexpected /proc/{pid}/maps read permission char");
// Handle write permission.
const char write_perm_char = line_extractor.GetChar();
if (write_perm_char == 'w')
memory_region_info.SetWritable(MemoryRegionInfo::OptionalBool::eYes);
else if (write_perm_char == '-')
memory_region_info.SetWritable(MemoryRegionInfo::OptionalBool::eNo);
else
return Error("unexpected /proc/{pid}/maps write permission char");
// Handle execute permission.
const char exec_perm_char = line_extractor.GetChar();
if (exec_perm_char == 'x')
memory_region_info.SetExecutable(MemoryRegionInfo::OptionalBool::eYes);
else if (exec_perm_char == '-')
memory_region_info.SetExecutable(MemoryRegionInfo::OptionalBool::eNo);
else
return Error("unexpected /proc/{pid}/maps exec permission char");
line_extractor.GetChar(); // Read the private bit
line_extractor.SkipSpaces(); // Skip the separator
line_extractor.GetHexMaxU64(false, 0); // Read the offset
line_extractor.GetHexMaxU64(false, 0); // Read the major device number
line_extractor.GetChar(); // Read the device id separator
line_extractor.GetHexMaxU64(false, 0); // Read the major device number
line_extractor.SkipSpaces(); // Skip the separator
line_extractor.GetU64(0, 10); // Read the inode number
line_extractor.SkipSpaces();
const char *name = line_extractor.Peek();
if (name)
memory_region_info.SetName(name);
return Error();
}
Error 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.
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
Error error;
if (m_supports_mem_region == LazyBool::eLazyBoolNo) {
// We're done.
error.SetErrorString("unsupported");
return error;
}
// 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()) {
error = ProcFileReader::ProcessLineByLine(
GetID(), "maps", [&](const std::string &line) -> bool {
MemoryRegionInfo info;
const Error parse_error =
ParseMemoryRegionInfoFromProcMapsLine(line, info);
if (parse_error.Success()) {
m_mem_region_cache.push_back(info);
return true;
} else {
if (log)
log->Printf("NativeProcessLinux::%s failed to parse proc maps "
"line '%s': %s",
__FUNCTION__, line.c_str(), error.AsCString());
return false;
}
});
// If we had an error, we'll mark unsupported.
if (error.Fail()) {
m_supports_mem_region = LazyBool::eLazyBoolNo;
return error;
} else 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.
if (log)
log->Printf("NativeProcessLinux::%s failed to find any procfs maps "
"entries, assuming no support for memory region metadata "
"retrieval",
__FUNCTION__);
m_supports_mem_region = LazyBool::eLazyBoolNo;
error.SetErrorString("not supported");
return error;
}
if (log)
log->Printf("NativeProcessLinux::%s read %" PRIu64
" memory region entries from /proc/%" PRIu64 "/maps",
__FUNCTION__,
static_cast<uint64_t>(m_mem_region_cache.size()), GetID());
// We support memory retrieval, remember that.
m_supports_mem_region = LazyBool::eLazyBoolYes;
} else {
if (log)
log->Printf("NativeProcessLinux::%s reusing %" PRIu64
" cached memory region entries",
__FUNCTION__,
static_cast<uint64_t>(m_mem_region_cache.size()));
}
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;
// 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();
// 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;
}
void NativeProcessLinux::DoStopIDBumped(uint32_t newBumpId) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
if (log)
log->Printf("NativeProcessLinux::%s(newBumpId=%" PRIu32 ") called",
__FUNCTION__, newBumpId);
if (log)
log->Printf("NativeProcessLinux::%s clearing %" PRIu64
" entries from the cache",
__FUNCTION__, static_cast<uint64_t>(m_mem_region_cache.size()));
m_mem_region_cache.clear();
}
Error 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 Error("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 Error();
} else {
addr = LLDB_INVALID_ADDRESS;
return Error("unable to allocate %" PRIu64
" bytes of memory with permissions %s",
size, GetPermissionsAsCString(permissions));
}
#endif
}
Error NativeProcessLinux::DeallocateMemory(lldb::addr_t addr) {
// FIXME see comments in AllocateMemory - required lower-level
// bits not in place yet (ThreadPlans)
return Error("not implemented");
}
lldb::addr_t NativeProcessLinux::GetSharedLibraryInfoAddress() {
// punt on this for now
return LLDB_INVALID_ADDRESS;
}
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();
}
bool NativeProcessLinux::GetArchitecture(ArchSpec &arch) const {
arch = m_arch;
return true;
}
Error NativeProcessLinux::GetSoftwareBreakpointPCOffset(
uint32_t &actual_opcode_size) {
// FIXME put this behind a breakpoint protocol class that can be
// set per architecture. Need ARM, MIPS support here.
static const uint8_t g_i386_opcode[] = {0xCC};
static const uint8_t g_s390x_opcode[] = {0x00, 0x01};
switch (m_arch.GetMachine()) {
case llvm::Triple::x86:
case llvm::Triple::x86_64:
actual_opcode_size = static_cast<uint32_t>(sizeof(g_i386_opcode));
return Error();
case llvm::Triple::systemz:
actual_opcode_size = static_cast<uint32_t>(sizeof(g_s390x_opcode));
return Error();
case llvm::Triple::arm:
case llvm::Triple::aarch64:
case llvm::Triple::mips64:
case llvm::Triple::mips64el:
case llvm::Triple::mips:
case llvm::Triple::mipsel:
// On these architectures the PC don't get updated for breakpoint hits
actual_opcode_size = 0;
return Error();
default:
assert(false && "CPU type not supported!");
return Error("CPU type not supported");
}
}
Error NativeProcessLinux::SetBreakpoint(lldb::addr_t addr, uint32_t size,
bool hardware) {
if (hardware)
return Error("NativeProcessLinux does not support hardware breakpoints");
else
return SetSoftwareBreakpoint(addr, size);
}
Error NativeProcessLinux::GetSoftwareBreakpointTrapOpcode(
size_t trap_opcode_size_hint, size_t &actual_opcode_size,
const uint8_t *&trap_opcode_bytes) {
// FIXME put this behind a breakpoint protocol class that can be set per
// architecture. Need MIPS support here.
static const uint8_t g_aarch64_opcode[] = {0x00, 0x00, 0x20, 0xd4};
// The ARM reference recommends the use of 0xe7fddefe and 0xdefe but the
// linux kernel does otherwise.
static const uint8_t g_arm_breakpoint_opcode[] = {0xf0, 0x01, 0xf0, 0xe7};
static const uint8_t g_i386_opcode[] = {0xCC};
static const uint8_t g_mips64_opcode[] = {0x00, 0x00, 0x00, 0x0d};
static const uint8_t g_mips64el_opcode[] = {0x0d, 0x00, 0x00, 0x00};
static const uint8_t g_s390x_opcode[] = {0x00, 0x01};
static const uint8_t g_thumb_breakpoint_opcode[] = {0x01, 0xde};
switch (m_arch.GetMachine()) {
case llvm::Triple::aarch64:
trap_opcode_bytes = g_aarch64_opcode;
actual_opcode_size = sizeof(g_aarch64_opcode);
return Error();
case llvm::Triple::arm:
switch (trap_opcode_size_hint) {
case 2:
trap_opcode_bytes = g_thumb_breakpoint_opcode;
actual_opcode_size = sizeof(g_thumb_breakpoint_opcode);
return Error();
case 4:
trap_opcode_bytes = g_arm_breakpoint_opcode;
actual_opcode_size = sizeof(g_arm_breakpoint_opcode);
return Error();
default:
assert(false && "Unrecognised trap opcode size hint!");
return Error("Unrecognised trap opcode size hint!");
}
case llvm::Triple::x86:
case llvm::Triple::x86_64:
trap_opcode_bytes = g_i386_opcode;
actual_opcode_size = sizeof(g_i386_opcode);
return Error();
case llvm::Triple::mips:
case llvm::Triple::mips64:
trap_opcode_bytes = g_mips64_opcode;
actual_opcode_size = sizeof(g_mips64_opcode);
return Error();
case llvm::Triple::mipsel:
case llvm::Triple::mips64el:
trap_opcode_bytes = g_mips64el_opcode;
actual_opcode_size = sizeof(g_mips64el_opcode);
return Error();
case llvm::Triple::systemz:
trap_opcode_bytes = g_s390x_opcode;
actual_opcode_size = sizeof(g_s390x_opcode);
return Error();
default:
assert(false && "CPU type not supported!");
return Error("CPU type not supported");
}
}
#if 0
ProcessMessage::CrashReason
NativeProcessLinux::GetCrashReasonForSIGSEGV(const siginfo_t *info)
{
ProcessMessage::CrashReason reason;
assert(info->si_signo == SIGSEGV);
reason = ProcessMessage::eInvalidCrashReason;
switch (info->si_code)
{
default:
assert(false && "unexpected si_code for SIGSEGV");
break;
case SI_KERNEL:
// Linux will occasionally send spurious SI_KERNEL codes.
// (this is poorly documented in sigaction)
// One way to get this is via unaligned SIMD loads.
reason = ProcessMessage::eInvalidAddress; // for lack of anything better
break;
case SEGV_MAPERR:
reason = ProcessMessage::eInvalidAddress;
break;
case SEGV_ACCERR:
reason = ProcessMessage::ePrivilegedAddress;
break;
}
return reason;
}
#endif
#if 0
ProcessMessage::CrashReason
NativeProcessLinux::GetCrashReasonForSIGILL(const siginfo_t *info)
{
ProcessMessage::CrashReason reason;
assert(info->si_signo == SIGILL);
reason = ProcessMessage::eInvalidCrashReason;
switch (info->si_code)
{
default:
assert(false && "unexpected si_code for SIGILL");
break;
case ILL_ILLOPC:
reason = ProcessMessage::eIllegalOpcode;
break;
case ILL_ILLOPN:
reason = ProcessMessage::eIllegalOperand;
break;
case ILL_ILLADR:
reason = ProcessMessage::eIllegalAddressingMode;
break;
case ILL_ILLTRP:
reason = ProcessMessage::eIllegalTrap;
break;
case ILL_PRVOPC:
reason = ProcessMessage::ePrivilegedOpcode;
break;
case ILL_PRVREG:
reason = ProcessMessage::ePrivilegedRegister;
break;
case ILL_COPROC:
reason = ProcessMessage::eCoprocessorError;
break;
case ILL_BADSTK:
reason = ProcessMessage::eInternalStackError;
break;
}
return reason;
}
#endif
#if 0
ProcessMessage::CrashReason
NativeProcessLinux::GetCrashReasonForSIGFPE(const siginfo_t *info)
{
ProcessMessage::CrashReason reason;
assert(info->si_signo == SIGFPE);
reason = ProcessMessage::eInvalidCrashReason;
switch (info->si_code)
{
default:
assert(false && "unexpected si_code for SIGFPE");
break;
case FPE_INTDIV:
reason = ProcessMessage::eIntegerDivideByZero;
break;
case FPE_INTOVF:
reason = ProcessMessage::eIntegerOverflow;
break;
case FPE_FLTDIV:
reason = ProcessMessage::eFloatDivideByZero;
break;
case FPE_FLTOVF:
reason = ProcessMessage::eFloatOverflow;
break;
case FPE_FLTUND:
reason = ProcessMessage::eFloatUnderflow;
break;
case FPE_FLTRES:
reason = ProcessMessage::eFloatInexactResult;
break;
case FPE_FLTINV:
reason = ProcessMessage::eFloatInvalidOperation;
break;
case FPE_FLTSUB:
reason = ProcessMessage::eFloatSubscriptRange;
break;
}
return reason;
}
#endif
#if 0
ProcessMessage::CrashReason
NativeProcessLinux::GetCrashReasonForSIGBUS(const siginfo_t *info)
{
ProcessMessage::CrashReason reason;
assert(info->si_signo == SIGBUS);
reason = ProcessMessage::eInvalidCrashReason;
switch (info->si_code)
{
default:
assert(false && "unexpected si_code for SIGBUS");
break;
case BUS_ADRALN:
reason = ProcessMessage::eIllegalAlignment;
break;
case BUS_ADRERR:
reason = ProcessMessage::eIllegalAddress;
break;
case BUS_OBJERR:
reason = ProcessMessage::eHardwareError;
break;
}
return reason;
}
#endif
Error 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(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
if (log)
log->Printf("NativeProcessLinux::%s using process_vm_readv to read %zd "
"bytes from inferior address 0x%" PRIx64 ": %s",
__FUNCTION__, size, addr,
success ? "Success" : strerror(errno));
if (success)
return Error();
// 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_ALL));
if (log)
ProcessPOSIXLog::IncNestLevel();
if (log && ProcessPOSIXLog::AtTopNestLevel() &&
log->GetMask().Test(POSIX_LOG_MEMORY))
log->Printf("NativeProcessLinux::%s(%p, %p, %zd, _)", __FUNCTION__,
(void *)addr, buf, size);
for (bytes_read = 0; bytes_read < size; bytes_read += remainder) {
Error error = NativeProcessLinux::PtraceWrapper(
PTRACE_PEEKDATA, GetID(), (void *)addr, nullptr, 0, &data);
if (error.Fail()) {
if (log)
ProcessPOSIXLog::DecNestLevel();
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);
if (log && ProcessPOSIXLog::AtTopNestLevel() &&
(log->GetMask().Test(POSIX_LOG_MEMORY_DATA_LONG) ||
(log->GetMask().Test(POSIX_LOG_MEMORY_DATA_SHORT) &&
size <= POSIX_LOG_MEMORY_SHORT_BYTES))) {
uintptr_t print_dst = 0;
// Format bytes from data by moving into print_dst for log output
for (unsigned i = 0; i < remainder; ++i)
print_dst |= (((data >> i * 8) & 0xFF) << i * 8);
log->Printf("NativeProcessLinux::%s() [0x%" PRIx64 "]:0x%" PRIx64
" (0x%" PRIx64 ")",
__FUNCTION__, addr, uint64_t(print_dst), uint64_t(data));
}
addr += k_ptrace_word_size;
dst += k_ptrace_word_size;
}
if (log)
ProcessPOSIXLog::DecNestLevel();
return Error();
}
Error NativeProcessLinux::ReadMemoryWithoutTrap(lldb::addr_t addr, void *buf,
size_t size,
size_t &bytes_read) {
Error error = ReadMemory(addr, buf, size, bytes_read);
if (error.Fail())
return error;
return m_breakpoint_list.RemoveTrapsFromBuffer(addr, buf, size);
}
Error 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;
Error error;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_ALL));
if (log)
ProcessPOSIXLog::IncNestLevel();
if (log && ProcessPOSIXLog::AtTopNestLevel() &&
log->GetMask().Test(POSIX_LOG_MEMORY))
log->Printf("NativeProcessLinux::%s(0x%" PRIx64 ", %p, %zu)", __FUNCTION__,
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);
if (log && ProcessPOSIXLog::AtTopNestLevel() &&
(log->GetMask().Test(POSIX_LOG_MEMORY_DATA_LONG) ||
(log->GetMask().Test(POSIX_LOG_MEMORY_DATA_SHORT) &&
size <= POSIX_LOG_MEMORY_SHORT_BYTES)))
log->Printf("NativeProcessLinux::%s() [%p]:0x%lx (0x%lx)", __FUNCTION__,
(void *)addr, *(const unsigned long *)src, data);
error = NativeProcessLinux::PtraceWrapper(PTRACE_POKEDATA, GetID(),
(void *)addr, (void *)data);
if (error.Fail()) {
if (log)
ProcessPOSIXLog::DecNestLevel();
return error;
}
} else {
unsigned char buff[8];
size_t bytes_read;
error = ReadMemory(addr, buff, k_ptrace_word_size, bytes_read);
if (error.Fail()) {
if (log)
ProcessPOSIXLog::DecNestLevel();
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()) {
if (log)
ProcessPOSIXLog::DecNestLevel();
return error;
}
if (log && ProcessPOSIXLog::AtTopNestLevel() &&
(log->GetMask().Test(POSIX_LOG_MEMORY_DATA_LONG) ||
(log->GetMask().Test(POSIX_LOG_MEMORY_DATA_SHORT) &&
size <= POSIX_LOG_MEMORY_SHORT_BYTES)))
log->Printf("NativeProcessLinux::%s() [%p]:0x%lx (0x%lx)", __FUNCTION__,
(void *)addr, *(const unsigned long *)src,
*(unsigned long *)buff);
}
addr += k_ptrace_word_size;
src += k_ptrace_word_size;
}
if (log)
ProcessPOSIXLog::DecNestLevel();
return error;
}
Error NativeProcessLinux::GetSignalInfo(lldb::tid_t tid, void *siginfo) {
return PtraceWrapper(PTRACE_GETSIGINFO, tid, nullptr, siginfo);
}
Error NativeProcessLinux::GetEventMessage(lldb::tid_t tid,
unsigned long *message) {
return PtraceWrapper(PTRACE_GETEVENTMSG, tid, nullptr, message);
}
Error NativeProcessLinux::Detach(lldb::tid_t tid) {
if (tid == LLDB_INVALID_THREAD_ID)
return Error();
return PtraceWrapper(PTRACE_DETACH, tid);
}
bool NativeProcessLinux::HasThreadNoLock(lldb::tid_t thread_id) {
for (auto thread_sp : m_threads) {
assert(thread_sp && "thread list should not contain NULL threads");
if (thread_sp->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 = GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD);
if (log)
log->Printf("NativeProcessLinux::%s (tid: %" PRIu64 ")", __FUNCTION__,
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;
}
}
SignalIfAllThreadsStopped();
return found;
}
NativeThreadLinuxSP NativeProcessLinux::AddThread(lldb::tid_t thread_id) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
if (log) {
log->Printf("NativeProcessLinux::%s pid %" PRIu64
" adding thread with tid %" PRIu64,
__FUNCTION__, 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);
auto thread_sp = std::make_shared<NativeThreadLinux>(this, thread_id);
m_threads.push_back(thread_sp);
return thread_sp;
}
Error NativeProcessLinux::FixupBreakpointPCAsNeeded(NativeThreadLinux &thread) {
Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_BREAKPOINTS));
Error error;
// Find out the size of a breakpoint (might depend on where we are in the
// code).
NativeRegisterContextSP context_sp = thread.GetRegisterContext();
if (!context_sp) {
error.SetErrorString("cannot get a NativeRegisterContext for the thread");
if (log)
log->Printf("NativeProcessLinux::%s failed: %s", __FUNCTION__,
error.AsCString());
return error;
}
uint32_t breakpoint_size = 0;
error = GetSoftwareBreakpointPCOffset(breakpoint_size);
if (error.Fail()) {
if (log)
log->Printf("NativeProcessLinux::%s GetBreakpointSize() failed: %s",
__FUNCTION__, error.AsCString());
return error;
} else {
if (log)
log->Printf("NativeProcessLinux::%s breakpoint size: %" PRIu32,
__FUNCTION__, breakpoint_size);
}
// First try probing for a breakpoint at a software breakpoint location: PC -
// breakpoint size.
const lldb::addr_t initial_pc_addr =
context_sp->GetPCfromBreakpointLocation();
lldb::addr_t breakpoint_addr = initial_pc_addr;
if (breakpoint_size > 0) {
// Do not allow breakpoint probe to wrap around.
if (breakpoint_addr >= breakpoint_size)
breakpoint_addr -= breakpoint_size;
}
// Check if we stopped because of a breakpoint.
NativeBreakpointSP breakpoint_sp;
error = m_breakpoint_list.GetBreakpoint(breakpoint_addr, breakpoint_sp);
if (!error.Success() || !breakpoint_sp) {
// We didn't find one at a software probe location. Nothing to do.
if (log)
log->Printf(
"NativeProcessLinux::%s pid %" PRIu64
" no lldb breakpoint found at current pc with adjustment: 0x%" PRIx64,
__FUNCTION__, GetID(), breakpoint_addr);
return Error();
}
// If the breakpoint is not a software breakpoint, nothing to do.
if (!breakpoint_sp->IsSoftwareBreakpoint()) {
if (log)
log->Printf("NativeProcessLinux::%s pid %" PRIu64
" breakpoint found at 0x%" PRIx64
", not software, nothing to adjust",
__FUNCTION__, GetID(), breakpoint_addr);
return Error();
}
//
// We have a software breakpoint and need to adjust the PC.
//
// Sanity check.
if (breakpoint_size == 0) {
// Nothing to do! How did we get here?
if (log)
log->Printf(
"NativeProcessLinux::%s pid %" PRIu64
" breakpoint found at 0x%" PRIx64
", it is software, but the size is zero, nothing to do (unexpected)",
__FUNCTION__, GetID(), breakpoint_addr);
return Error();
}
// Change the program counter.
if (log)
log->Printf("NativeProcessLinux::%s pid %" PRIu64 " tid %" PRIu64
": changing PC from 0x%" PRIx64 " to 0x%" PRIx64,
__FUNCTION__, GetID(), thread.GetID(), initial_pc_addr,
breakpoint_addr);
error = context_sp->SetPC(breakpoint_addr);
if (error.Fail()) {
if (log)
log->Printf("NativeProcessLinux::%s pid %" PRIu64 " tid %" PRIu64
": failed to set PC: %s",
__FUNCTION__, GetID(), thread.GetID(), error.AsCString());
return error;
}
return error;
}
Error NativeProcessLinux::GetLoadedModuleFileSpec(const char *module_path,
FileSpec &file_spec) {
FileSpec module_file_spec(module_path, true);
bool found = false;
file_spec.Clear();
ProcFileReader::ProcessLineByLine(
GetID(), "maps", [&](const std::string &line) {
SmallVector<StringRef, 16> columns;
StringRef(line).split(columns, " ", -1, false);
if (columns.size() < 6)
return true; // continue searching
FileSpec this_file_spec(columns[5].str().c_str(), false);
if (this_file_spec.GetFilename() != module_file_spec.GetFilename())
return true; // continue searching
file_spec = this_file_spec;
found = true;
return false; // we are done
});
if (!found)
return Error("Module file (%s) not found in /proc/%" PRIu64 "/maps file!",
module_file_spec.GetFilename().AsCString(), GetID());
return Error();
}
Error NativeProcessLinux::GetFileLoadAddress(const llvm::StringRef &file_name,
lldb::addr_t &load_addr) {
load_addr = LLDB_INVALID_ADDRESS;
Error error = ProcFileReader::ProcessLineByLine(
GetID(), "maps", [&](const std::string &line) -> bool {
StringRef maps_row(line);
SmallVector<StringRef, 16> maps_columns;
maps_row.split(maps_columns, StringRef(" "), -1, false);
if (maps_columns.size() < 6) {
// Return true to continue reading the proc file
return true;
}
if (maps_columns[5] == file_name) {
StringExtractor addr_extractor(maps_columns[0].str().c_str());
load_addr = addr_extractor.GetHexMaxU64(false, LLDB_INVALID_ADDRESS);
// Return false to stop reading the proc file further
return false;
}
// Return true to continue reading the proc file
return true;
});
return error;
}
NativeThreadLinuxSP NativeProcessLinux::GetThreadByID(lldb::tid_t tid) {
return std::static_pointer_cast<NativeThreadLinux>(
NativeProcessProtocol::GetThreadByID(tid));
}
Error NativeProcessLinux::ResumeThread(NativeThreadLinux &thread,
lldb::StateType state, int signo) {
Log *const log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD);
if (log)
log->Printf("NativeProcessLinux::%s (tid: %" PRIu64 ")", __FUNCTION__,
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 && log) {
log->Printf("NativeProcessLinux::%s about to resume tid %" PRIu64
" per explicit request but we have a pending stop notification "
"(tid %" PRIu64 ") that is actively waiting for this thread to "
"stop. Valid sequence of events?",
__FUNCTION__, 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:
if (log)
log->Printf("NativeProcessLinux::%s Unhandled state %s.", __FUNCTION__,
StateAsCString(state));
llvm_unreachable("Unhandled state for resume");
}
}
//===----------------------------------------------------------------------===//
void NativeProcessLinux::StopRunningThreads(const lldb::tid_t triggering_tid) {
Log *const log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD);
if (log) {
log->Printf("NativeProcessLinux::%s about to process event: "
"(triggering_tid: %" PRIu64 ")",
__FUNCTION__, 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_sp : m_threads) {
if (StateIsRunningState(thread_sp->GetState()))
static_pointer_cast<NativeThreadLinux>(thread_sp)->RequestStop();
}
SignalIfAllThreadsStopped();
if (log) {
log->Printf("NativeProcessLinux::%s event processing done", __FUNCTION__);
}
}
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) {
Error error = RemoveBreakpoint(thread_info.second);
if (error.Fail())
if (log)
log->Printf("NativeProcessLinux::%s() pid = %" PRIu64
" remove stepping breakpoint: %s",
__FUNCTION__, thread_info.first, error.AsCString());
}
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 = GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD);
if (log)
log->Printf("NativeProcessLinux::%s (tid: %" PRIu64 ")", __FUNCTION__,
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(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
// Process all pending waitpid notifications.
while (true) {
int status = -1;
::pid_t wait_pid = waitpid(-1, &status, __WALL | __WNOTHREAD | WNOHANG);
if (wait_pid == 0)
break; // We are done.
if (wait_pid == -1) {
if (errno == EINTR)
continue;
Error error(errno, eErrorTypePOSIX);
if (log)
log->Printf("NativeProcessLinux::%s waitpid (-1, &status, __WALL | "
"__WNOTHREAD | WNOHANG) failed: %s",
__FUNCTION__, error.AsCString());
break;
}
bool exited = false;
int signal = 0;
int exit_status = 0;
const char *status_cstr = nullptr;
if (WIFSTOPPED(status)) {
signal = WSTOPSIG(status);
status_cstr = "STOPPED";
} else if (WIFEXITED(status)) {
exit_status = WEXITSTATUS(status);
status_cstr = "EXITED";
exited = true;
} else if (WIFSIGNALED(status)) {
signal = WTERMSIG(status);
status_cstr = "SIGNALED";
if (wait_pid == static_cast<::pid_t>(GetID())) {
exited = true;
exit_status = -1;
}
} else
status_cstr = "(\?\?\?)";
if (log)
log->Printf("NativeProcessLinux::%s: waitpid (-1, &status, __WALL | "
"__WNOTHREAD | WNOHANG)"
"=> pid = %" PRIi32
", status = 0x%8.8x (%s), signal = %i, exit_state = %i",
__FUNCTION__, wait_pid, status, status_cstr, signal,
exit_status);
MonitorCallback(wait_pid, exited, signal, exit_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*)
Error NativeProcessLinux::PtraceWrapper(int req, lldb::pid_t pid, void *addr,
void *data, size_t data_size,
long *result) {
Error 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;
if (log)
log->Printf("ptrace(%d, %" PRIu64 ", %p, %p, %zu)=%lX", req, pid, addr,
data, data_size, ret);
PtraceDisplayBytes(req, data, data_size);
if (log && error.GetError() != 0) {
const char *str;
switch (error.GetError()) {
case ESRCH:
str = "ESRCH";
break;
case EINVAL:
str = "EINVAL";
break;
case EBUSY:
str = "EBUSY";
break;
case EPERM:
str = "EPERM";
break;
default:
str = error.AsCString();
}
log->Printf("ptrace() failed; errno=%d (%s)", error.GetError(), str);
}
return error;
}
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