[lldb] [Process/NetBSD] Implement thread name getting

[mgorny]

Summary

Implement thread name getting sysctl() on NetBSD. Also fix the incorrect type in pthread_setname_np() in the relevant test.

[mgorny]

Went a bit further and implemented the missing feature.

[krytarowski]

lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.cpp

23

Please include before this header <sys/types.h>. If it works, that header is likely pulled from some indirect location.

[mgorny]

Added sys/types.h.

[labath]

lldb/packages/Python/lldbsuite/test/tools/lldb-server/thread-name/main.cpp

13

I think const_cast<char *>(name) ought to be enough.

lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.cpp

123

Thread-safety technically doesn't matter in this part of the code, but I think it would be good practice to use llvm::StrError (llvm/Support/Errno.h) anyway.

[krytarowski]

lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.cpp

123

strerror is thread safe on NetBSD, but probably better to pick llvm interfaces.

[mgorny]

Implemented review suggestions. Thanks!

lldb/packages/Python/lldbsuite/test/tools/lldb-server/thread-name/TestGdbRemoteThreadName.py

def run_and_check_name(self, expected_name):
         self.assertIsNotNone(context)
 
         sigint = lldbutil.get_signal_number("SIGINT")
         self.assertEqual(sigint, int(context.get("signal"), 16))
         kv_dict = self.parse_key_val_dict(context.get("key_vals_text"))
         self.assertEqual(expected_name, kv_dict.get("name"))
 
     @skipIfWindows # the test is not updated for Windows.
-    @skipIfNetBSD # build failure due to pthread_setname_np prototype
     @llgs_test
     def test(self):
         """ Make sure lldb-server can retrieve inferior thread name"""
         self.init_llgs_test()
         self.build()
         self.set_inferior_startup_launch()
         procs = self.prep_debug_monitor_and_inferior()
 
         self.run_and_check_name("hello world")
         self.run_and_check_name("goodbye world")

lldb/packages/Python/lldbsuite/test/tools/lldb-server/thread-name/main.cpp

 #include <pthread.h>
 #include <signal.h>
 
 void set_thread_name(const char *name) {
 #if defined(__APPLE__)
   ::pthread_setname_np(name);
 #elif defined(__FreeBSD__)
   ::pthread_set_name_np(::pthread_self(), name);
 #elif defined(__linux__)
   ::pthread_setname_np(::pthread_self(), name);
 #elif defined(__NetBSD__)
-  ::pthread_setname_np(::pthread_self(), "%s", name);
+  ::pthread_setname_np(::pthread_self(), "%s", const_cast<char *>(name));
 #endif
 }
 
 int main() {
   set_thread_name("hello world");
   raise(SIGINT);
   set_thread_name("goodbye world");
   raise(SIGINT);
   return 0;
 }

lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.cpp

 
 #include "NativeProcessNetBSD.h"
 
 #include "Plugins/Process/POSIX/CrashReason.h"
 #include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
 #include "lldb/Utility/LLDBAssert.h"
 #include "lldb/Utility/RegisterValue.h"
 #include "lldb/Utility/State.h"
+#include "llvm/Support/Errno.h"
 
 #include <sstream>
 
+// clang-format off
+#include <sys/types.h>
+#include <sys/sysctl.h>
+// clang-format on
+
 using namespace lldb;
 using namespace lldb_private;
 using namespace lldb_private::process_netbsd;
 
 NativeThreadNetBSD::NativeThreadNetBSD(NativeProcessNetBSD &process,
                                        lldb::tid_t tid)
     : NativeThreadProtocol(process, tid), m_state(StateType::eStateInvalid),
       m_stop_info(), m_reg_context_up(
void NativeThreadNetBSD::SetRunning() {
   m_stop_info.reason = StopReason::eStopReasonNone;
 }
 
 void NativeThreadNetBSD::SetStepping() {
   m_state = StateType::eStateStepping;
   m_stop_info.reason = StopReason::eStopReasonNone;
 }
 
-std::string NativeThreadNetBSD::GetName() { return std::string(""); }
+std::string NativeThreadNetBSD::GetName() {
+  Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD));
+
+  std::vector<struct kinfo_lwp> infos;
+  int mib[5] = {CTL_KERN, KERN_LWP, static_cast<int>(m_process.GetID()),
+                sizeof(struct kinfo_lwp), 0};
+  size_t size;
+
+  if (::sysctl(mib, 5, nullptr, &size, nullptr, 0) == -1 || size == 0) {
+    LLDB_LOG(log, "sysctl() for LWP info size failed: {0}",
+             llvm::sys::StrError());
+    return "";
+  }
+
+  mib[4] = size / sizeof(size_t);
+  infos.resize(size / sizeof(struct kinfo_lwp));
+
+  if (sysctl(mib, 5, infos.data(), &size, NULL, 0) == -1 || size == 0) {
+    LLDB_LOG(log, "sysctl() for LWP info failed: {0}", llvm::sys::StrError());
+    return "";
+  }
+
+  size_t nlwps = size / sizeof(struct kinfo_lwp);
+  for (size_t i = 0; i < nlwps; i++) {
+    if (static_cast<lldb::tid_t>(infos[i].l_lid) == m_tid) {
+      return infos[i].l_name;
+    }
+  }
+
+  LLDB_LOG(log, "unable to find lwp {0} in LWP infos", m_tid);
+  return "";
+}
 
 lldb::StateType NativeThreadNetBSD::GetState() { return m_state; }
 
 bool NativeThreadNetBSD::GetStopReason(ThreadStopInfo &stop_info,
                                        std::string &description) {
   Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD));
 
   description.clear();