kernel/debug: Report killing signals

Adds a `signal` field to the `team_deleted` event. Since killing
signals like `SIGKILL` and `SIGKILLTHR` do not generate a
`signal_received` event, debuggers would only see a `team_deleted`
message with the `status` field set to 0. This makes debuggers like
GDB think that the debuggee has exited with a status code of 0.

To correctly report these signals, when a killing signal is sent
to a team, this signal is relayed to the main thread instead of
defaulting to just a `SIGKILLTHR` for both cases.

Change-Id: If69c9e2e4d87bfbd31f654f5cb6f696ac69ef777
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7756
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: waddlesplash <[email protected]>

headers/os/kernel/debugger.h

@@ -561,6 +561,7 @@ typedef struct {
 	debug_origin	origin;			// thread is < 0, team is the deleted team
 									// (asynchronous message)
 	status_t		status;			// the exit code of the team
+	int				signal;			// the signal causing the exit, < 0 if none
 	team_usage_info	usage;			// the usage info of the team
 } debug_team_deleted;
 

headers/private/kernel/user_debugger.h

@@ -259,7 +259,7 @@ bool user_debug_handle_signal(int signal, struct sigaction *handler,
 void user_debug_stop_thread();
 void user_debug_team_created(team_id teamID);
 void user_debug_team_deleted(team_id teamID, port_id debuggerPort, status_t status,
-		team_usage_info* usageInfo);
+		int signal, team_usage_info* usageInfo);
 void user_debug_team_exec();
 void user_debug_update_new_thread_flags(Thread* thread);
 void user_debug_thread_created(thread_id threadID);

src/system/kernel/debug/user_debugger.cpp

@@ -1000,7 +1000,7 @@ user_debug_team_created(team_id teamID)
 
 
 void
-user_debug_team_deleted(team_id teamID, port_id debuggerPort, status_t status,
+user_debug_team_deleted(team_id teamID, port_id debuggerPort, status_t status, int signal,
 	team_usage_info* usageInfo)
 {
 	if (debuggerPort >= 0) {
@@ -1012,6 +1012,7 @@ user_debug_team_deleted(team_id teamID, port_id debuggerPort, status_t status,
 		message.origin.team = teamID;
 		message.origin.nub_port = -1;
 		message.status = status;
+		message.signal = signal;
 		message.usage = *usageInfo;
 		write_port_etc(debuggerPort, B_DEBUGGER_MESSAGE_TEAM_DELETED, &message,
 			sizeof(message), B_RELATIVE_TIMEOUT, 0);

src/system/kernel/signal.cpp

@@ -1654,7 +1654,7 @@ send_signal_to_team_locked(Team* team, uint32 signalNumber, Signal* signal,
 			// (only the main thread shuts down the team).
 			Thread* mainThread = team->main_thread;
 			if (mainThread != NULL) {
-				mainThread->AddPendingSignal(SIGKILLTHR);
+				mainThread->AddPendingSignal(signalNumber);
 
 				// wake up main thread
 				mainThread->going_to_suspend = false;

src/system/kernel/team.cpp

@@ -3345,7 +3345,17 @@ team_delete_team(Team* team, port_id debuggerPort)
 	}
 
 	// get team exit information
-	status_t exitStatus = team->exit.status;
+	status_t exitStatus = -1;
+	int signal = -1;
+
+	switch (team->exit.reason) {
+		case CLD_EXITED:
+			exitStatus = team->exit.status;
+			break;
+		case CLD_KILLED:
+			signal = team->exit.signal;
+			break;
+	}
 
 	teamLocker.Unlock();
 
@@ -3371,7 +3381,7 @@ team_delete_team(Team* team, port_id debuggerPort)
 	team->ReleaseReference();
 
 	// notify the debugger, that the team is gone
-	user_debug_team_deleted(teamID, debuggerPort, exitStatus, &usageInfo);
+	user_debug_team_deleted(teamID, debuggerPort, exitStatus, signal, &usageInfo);
 }