Implement QPassSignals GDB package in lldb-server

Summary: QPassSignals package allows lldb client to tell lldb-server to ignore certain types of signals and re-inject them back to inferior without stopping execution.

Reviewers: jmajors, labath

Subscribers: danalbert, srhines, emaste, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D30286
Author: Eugene Zemtsov <ezemtsov@google.com>

llvm-svn: 296101

5 files changed, 48 insertions, 5 deletions

diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
index c3b6f4c352d..1ff8893192f 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -1037,6 +1037,13 @@ void NativeProcessLinux::MonitorSignal(const siginfo_t &info,
     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);
diff --git a/lldb/source/Plugins/Process/POSIX/CrashReason.cpp b/lldb/source/Plugins/Process/POSIX/CrashReason.cpp
index 77d6e287486..864418c9003 100644
--- a/lldb/source/Plugins/Process/POSIX/CrashReason.cpp
+++ b/lldb/source/Plugins/Process/POSIX/CrashReason.cpp
@@ -62,7 +62,6 @@ CrashReason GetCrashReasonForSIGSEGV(const siginfo_t &info) {
     return CrashReason::eBoundViolation;
   }
 
-  assert(false && "unexpected si_code for SIGSEGV");
   return CrashReason::eInvalidCrashReason;
 }
 
@@ -88,7 +87,6 @@ CrashReason GetCrashReasonForSIGILL(const siginfo_t &info) {
     return CrashReason::eInternalStackError;
   }
 
-  assert(false && "unexpected si_code for SIGILL");
   return CrashReason::eInvalidCrashReason;
 }
 
@@ -114,7 +112,6 @@ CrashReason GetCrashReasonForSIGFPE(const siginfo_t &info) {
     return CrashReason::eFloatSubscriptRange;
   }
 
-  assert(false && "unexpected si_code for SIGFPE");
   return CrashReason::eInvalidCrashReason;
 }
 
@@ -130,7 +127,6 @@ CrashReason GetCrashReasonForSIGBUS(const siginfo_t &info) {
     return CrashReason::eHardwareError;
   }
 
-  assert(false && "unexpected si_code for SIGBUS");
   return CrashReason::eInvalidCrashReason;
 }
 }
@@ -158,7 +154,7 @@ std::string GetCrashReasonString(CrashReason reason, lldb::addr_t fault_addr) {
 
   switch (reason) {
   default:
-    assert(false && "invalid CrashReason");
+    str = "unknown crash reason";
     break;
 
   case CrashReason::eInvalidAddress:
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
index 4e3c91b0473..82f8ff80497 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -838,6 +838,7 @@ GDBRemoteCommunicationServerCommon::Handle_qSupported(
   response.PutCString(";QListThreadsInStopReply+");
   response.PutCString(";qEcho+");
 #if defined(__linux__)
+  response.PutCString(";QPassSignals+");
   response.PutCString(";qXfer:auxv:read+");
 #endif
 
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
index b8f49973ad4..0beabc60ddc 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -181,6 +181,9 @@ void GDBRemoteCommunicationServerLLGS::RegisterPacketHandlers() {
                                 &GDBRemoteCommunicationServerLLGS::Handle_Z);
   RegisterMemberFunctionHandler(StringExtractorGDBRemote::eServerPacketType_z,
                                 &GDBRemoteCommunicationServerLLGS::Handle_z);
+  RegisterMemberFunctionHandler(
+      StringExtractorGDBRemote::eServerPacketType_QPassSignals,
+      &GDBRemoteCommunicationServerLLGS::Handle_QPassSignals);
 
   RegisterPacketHandler(StringExtractorGDBRemote::eServerPacketType_k,
                         [this](StringExtractorGDBRemote packet, Error &error,
@@ -3072,6 +3075,40 @@ GDBRemoteCommunicationServerLLGS::Handle_qFileLoadAddress(
   return SendPacketNoLock(response.GetString());
 }
 
+GDBRemoteCommunication::PacketResult
+GDBRemoteCommunicationServerLLGS::Handle_QPassSignals(
+    StringExtractorGDBRemote &packet) {
+  std::vector<int> signals;
+  packet.SetFilePos(strlen("QPassSignals:"));
+
+  // Read sequence of hex signal numbers divided by a semicolon and
+  // optionally spaces.
+  while (packet.GetBytesLeft() > 0) {
+    int signal = packet.GetS32(-1, 16);
+    if (signal < 0)
+      return SendIllFormedResponse(packet, "Failed to parse signal number.");
+    signals.push_back(signal);
+
+    packet.SkipSpaces();
+    char separator = packet.GetChar();
+    if (separator == '\0')
+      break; // End of string
+    if (separator != ';')
+      return SendIllFormedResponse(packet, "Invalid separator,"
+                                            " expected semicolon.");
+  }
+
+  // Fail if we don't have a current process.
+  if (!m_debugged_process_sp)
+    return SendErrorResponse(68);
+
+  Error error = m_debugged_process_sp->IgnoreSignals(signals);
+  if (error.Fail())
+    return SendErrorResponse(69);
+
+  return SendOKResponse();
+}
+
 void GDBRemoteCommunicationServerLLGS::MaybeCloseInferiorTerminalConnection() {
   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS));
 
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
index fa52cdaab49..e255b4cc486 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
@@ -203,6 +203,8 @@ protected:
 
   PacketResult Handle_qFileLoadAddress(StringExtractorGDBRemote &packet);
 
+  PacketResult Handle_QPassSignals(StringExtractorGDBRemote &packet);
+
   void SetCurrentThreadID(lldb::tid_t tid);
 
   lldb::tid_t GetCurrentThreadID() const;