llgs: add proper exec support for Linux.
This change:
* properly captures execs in NativeProcessLinux.
* clears out all non-main-thread thread metadata in NativeProcessLinux on exec.
* adds a DidExec() method to the NativeProcessProtocol delegate.
* clears out the auxv data cache when we exec (on Linux).
This is a small part of the llgs for local Linux debugging work going on here:
https://github.com/tfiala/lldb/tree/dev-llgs-local
I'm breaking it into small patches.
llvm-svn: 216670
diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
index f004a8e..22f355a 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -1953,19 +1953,31 @@
if (ptrace_err == EINVAL)
{
// This is the first part of the Linux ptrace group-stop mechanism.
+ // (The other thing it can conceivably be is a call on a pid that no
+ // longer exists for some reason).
// The tracer (i.e. NativeProcessLinux) is expected to inject the signal
// into the tracee (i.e. inferior) at this point.
if (log)
- log->Printf ("NativeProcessLinux::%s() resuming from group-stop", __FUNCTION__);
+ log->Printf ("NativeProcessLinux::%s resuming from group-stop", __FUNCTION__);
// The inferior process is in 'group-stop', so deliver the stopping signal.
const bool signal_delivered = process->Resume (pid, info.si_signo);
if (log)
- log->Printf ("NativeProcessLinux::%s() pid %" PRIu64 " group-stop signal delivery of signal 0x%x (%s) - %s", __FUNCTION__, pid, info.si_signo, GetUnixSignals ().GetSignalAsCString (info.si_signo), signal_delivered ? "success" : "failed");
+ log->Printf ("NativeProcessLinux::%s pid %" PRIu64 " group-stop signal delivery of signal 0x%x (%s) - %s", __FUNCTION__, pid, info.si_signo, GetUnixSignals ().GetSignalAsCString (info.si_signo), signal_delivered ? "success" : "failed");
- assert(signal_delivered && "SIGSTOP delivery failed while in 'group-stop' state");
+ if (signal_delivered)
+ {
+ // All is well.
+ stop_monitoring = false;
+ }
+ else
+ {
+ if (log)
+ log->Printf ("NativeProcessLinux::%s pid %" PRIu64 " something looks horribly wrong - like the process we're monitoring died. Stop monitoring it.", __FUNCTION__, pid);
- stop_monitoring = false;
+ // Stop monitoring now.
+ return true;
+ }
}
else
{
@@ -2079,10 +2091,63 @@
}
case (SIGTRAP | (PTRACE_EVENT_EXEC << 8)):
+ {
+ NativeThreadProtocolSP main_thread_sp;
+
if (log)
log->Printf ("NativeProcessLinux::%s() received exec event, code = %d", __FUNCTION__, info->si_code ^ SIGTRAP);
- // FIXME stop all threads, mark thread stop reason as ThreadStopInfo.reason = eStopReasonExec;
+
+ // Remove all but the main thread here.
+ // FIXME check if we really need to do this - how does ptrace behave under exec when multiple threads were present
+ // before the exec? If we get all the detach signals right, we don't need to do this. However, it makes it clearer
+ // what we should really be tracking.
+ {
+ Mutex::Locker locker (m_threads_mutex);
+
+ 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 = 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 ());
+ reinterpret_cast<NativeThreadLinux*>(main_thread_sp.get())->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 ());
+ }
+ }
+
+ // 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");
+ SetState (StateType::eStateStopped);
+
break;
+ }
case (SIGTRAP | (PTRACE_EVENT_EXIT << 8)):
{