1 files changed, 385 insertions, 0 deletions
diff --git a/src/shm.cc b/src/shm.cc
new file mode 100644
index 0000000..5cd4a52
--- /dev/null
+++ b/src/shm.cc
@@ -0,0 +1,385 @@
+#include "main.hh"
+
+// NOTE(fusion): This looks like an interface to external tools. Looking at the
+// `bin` directory this program was in, there are other programs that probably
+// use this interface to control certain aspects of the server. My previous
+// assumption that each connection was dispatched into its own process may not
+// be correct after all.
+
+struct TSharedMemory {
+	int Command;
+	char CommandBuffer[256];
+	uint32 RoundNr;
+	uint32 ObjectCounter;
+	uint32 Errors;
+	int PlayersOnline;
+	int NewbiesOnline;
+	int PrintBufferPosition;
+	char PrintBuffer[200][128];
+	GAMESTATE GameState;
+	pid_t GameThreadPID;
+};
+
+static TSharedMemory *SHM = NULL;
+static bool IsGameServer = false;
+static bool VerboseOutput = false;
+
+void StartGame(void){
+	if(SHM != NULL){
+		if(SHM->GameState == GAME_STARTING){
+			SHM->GameState = GAME_RUNNING;
+		}
+	}else{
+		error("StartGame: SharedMemory existiert nicht.\n");
+	}
+}
+
+void CloseGame(void){
+	if(SHM != NULL){
+		if(SHM->GameState == GAME_RUNNING){
+			SHM->GameState = GAME_CLOSING;
+		}
+	}else{
+		error("CloseGame: SharedMemory existiert nicht.\n");
+	}
+}
+
+void EndGame(void){
+	if(SHM != NULL){
+		SHM->GameState = GAME_ENDING;
+	}else{
+		error("EndGame: SharedMemory existiert nicht.\n");
+	}
+}
+
+bool LoginAllowed(void){
+	bool Result = false;
+	if(SHM != NULL){
+		Result = SHM->GameState == GAME_RUNNING;
+	}else{
+		error("IsLoginAllowed: SharedMemory existiert nicht.\n");
+	}
+	return Result;
+}
+
+bool GameRunning(void){
+	bool Result = false;
+	if(SHM != NULL){
+		Result = SHM->GameState == GAME_STARTING
+				|| SHM->GameState == GAME_RUNNING
+				|| SHM->GameState == GAME_CLOSING;
+	}else{
+		error("GameRunning: SharedMemory existiert nicht.\n");
+	}
+	return Result;
+}
+
+bool GameStarting(void){
+	bool Result = false;
+	if(SHM != NULL){
+		Result = SHM->GameState == GAME_STARTING;
+	}else{
+		error("GameStarting: SharedMemory existiert nicht.\n");
+	}
+	return Result;
+}
+
+bool GameEnding(void){
+	bool Result = false;
+	if(SHM != NULL){
+		Result = SHM->GameState == GAME_CLOSING
+				|| SHM->GameState == GAME_ENDING;
+	}else{
+		error("GameEnding: SharedMemory existiert nicht.\n");
+	}
+	return Result;
+}
+
+pid_t GetGameThreadPID(void){
+	pid_t Pid = 0;
+	if(SHM != NULL){
+		Pid = SHM->GameThreadPID;
+	}
+	return Pid;
+}
+
+static void ErrorHandler(char *Text){
+	if(VerboseOutput){
+		printf("%s", Text);
+	}
+
+	if(SHM != NULL){
+		SHM->Errors += 1;
+		if(SHM->Errors <= 0x8000){
+			Log("error", Text);
+			if(SHM->Errors == 0x8000){
+				Log("error", "Zu viele Fehler. Keine weitere Protokollierung.\n");
+			}
+		}
+	}
+}
+
+static void PrintHandler(int Level, char *Text){
+	static Semaphore LogfileMutex(1);
+
+	if(Level > DebugLevel){
+		return;
+	}
+
+	if(VerboseOutput){
+		printf("%s", Text);
+	}
+
+	if(SHM != NULL){
+		// TODO(fusion): Does it even make sense to have this Semaphore here?
+		// It controls writes to the print buffer but reads outside this scope
+		// may be partial. But then, it doesn't seem like it is read anywhere
+		// else. Perhaps some external monitor tool, in which case do we even
+		// print from multiple threads?
+		LogfileMutex.down();
+		int Line = SHM->PrintBufferPosition;
+		char *Buffer = SHM->PrintBuffer[Line];
+		// TODO(fusion): Ughh...
+		strncpy(Buffer, Text, sizeof(SHM->PrintBuffer[0]) - 1);
+		Buffer[sizeof(SHM->PrintBuffer[0]) - 2] = 0;
+		if(Buffer[0] != 0){
+			usize TextLen = strlen(Buffer);
+			if(Buffer[TextLen - 1] != '\n'){
+				strcat(Buffer, "\n");
+			}
+		}
+		SHM->PrintBufferPosition = (Line + 1) % NARRAY(SHM->PrintBuffer);
+		LogfileMutex.up();
+	}
+}
+
+int GetPrintlogPosition(void){
+	int Result = 0;
+	if(SHM != NULL){
+		Result = SHM->PrintBufferPosition;
+	}
+	return Result;
+}
+
+char *GetPrintlogLine(int Line){
+	char *Result = NULL;
+	if(SHM != NULL && Line >= 0 && Line < NARRAY(SHM->PrintBuffer)){
+		Result = SHM->PrintBuffer[Line];
+	}
+	return Result;
+}
+
+void IncrementObjectCounter(void){
+	if(SHM != NULL){
+		SHM->ObjectCounter += 1;
+	}
+}
+
+void DecrementObjectCounter(void){
+	if(SHM != NULL){
+		SHM->ObjectCounter -= 1;
+	}
+}
+
+uint32 GetObjectCounter(void){
+	uint32 ObjectCounter = 0;
+	if(SHM != NULL){
+		ObjectCounter = SHM->ObjectCounter;
+	}
+	return ObjectCounter;
+}
+
+void IncrementPlayersOnline(void){
+	if(SHM != NULL){
+		SHM->PlayersOnline += 1;
+	}
+}
+
+void DecrementPlayersOnline(void){
+	if(SHM != NULL){
+		SHM->PlayersOnline -= 1;
+	}
+}
+
+int GetPlayersOnline(void){
+	int PlayersOnline = 0;
+	if(SHM != NULL){
+		PlayersOnline = SHM->PlayersOnline;
+	}
+	return PlayersOnline;
+}
+
+void IncrementNewbiesOnline(void){
+	if(SHM != NULL){
+		SHM->NewbiesOnline += 1;
+	}
+}
+
+void DecrementNewbiesOnline(void){
+	if(SHM != NULL){
+		SHM->NewbiesOnline -= 1;
+	}
+}
+
+int GetNewbiesOnline(void){
+	int NewbiesOnline = 0;
+	if(SHM != NULL){
+		NewbiesOnline = SHM->NewbiesOnline;
+	}
+	return NewbiesOnline;
+}
+
+void SetRoundNr(uint32 RoundNr){
+	if(SHM != NULL){
+		SHM->RoundNr = RoundNr;
+	}
+}
+
+uint32 GetRoundNr(void){
+	uint32 RoundNr = 0;
+	if(SHM != NULL){
+		RoundNr = SHM->RoundNr;
+	}
+	return RoundNr;
+}
+
+void SetCommand(int Command, char *Text){
+	if(SHM != NULL){
+		SHM->Command = Command;
+		if(Text == NULL){
+			SHM->CommandBuffer[0] = 0;
+		}else{
+			strncpy(SHM->CommandBuffer, sizeof(SHM->CommandBuffer), Text);
+			SHM->CommandBuffer[sizeof(SHM->CommandBuffer) - 1] = 0;
+		}
+	}
+}
+
+int GetCommand(void){
+	int Command = 0;
+	if(SHM != NULL){
+		Command = SHM->Command;
+	}
+	return Command;
+}
+
+char *GetCommandBuffer(void){
+	char *Buffer = NULL;
+	if(SHM != NULL && SHM->Command != 0){
+		Buffer = SHM->CommandBuffer;
+	}
+	return Buffer;
+}
+
+static bool DeleteSHM(void){
+	int SHMID = shmget(SHMKey, 0, 0);
+	if(SHMID == -1){
+		if(VerboseOutput){
+			puts("DeleteSHM: SharedMemory existiert nicht.");
+		}
+		return true;
+	}
+
+	if(shmctl(SHMID, IPC_RMID, NULL) == -1){
+		if(VerboseOutput){
+			// TODO(fusion): Include `errno` in the error message?
+			puts("DeleteSHM: Kann SharedMemory nicht löschen.");
+		}
+		return false;
+	}
+
+	return true;
+}
+
+static void CreateSHM(void){
+	bool Deleted = false;
+	while(true){
+		int SHMID = shmget(SHMKey, sizeof(TSharedMemory), IPC_CREAT | IPC_EXCL | 0777);
+		if(SHMID != -1){
+			return;
+		}
+
+		if(errno != EEXIST || Deleted){
+			if(VerboseOutput){
+				printf("CreateSHM: Kann SharedMemory nicht anlegen (Fehler %d).\n", errno);
+			}
+			throw "Cannot create SharedMemory";
+		}
+
+		if(!DeleteSHM()){
+			throw "Cannot delete SharedMemory";
+		}
+
+		Deleted = true;
+	}
+}
+
+static void AttachSHM(void){
+	int SHMID = shmget(SHMKey, sizeof(TSharedMemory), 0);
+	if(SHMID == -1){
+		if(VerboseOutput){
+			// TODO(fusion): Include `errno` in the error message?
+			puts("AttachSHM: Kann SharedMemory nicht fassen.");
+		}
+		SHM = NULL;
+		throw "Cannot get SharedMemory";
+	}
+
+	SHM = (TSharedMemory*)shmat(SHMID, NULL, 0);
+	if(SHM == (void*)-1){
+		if(VerboseOutput){
+			puts("AttachSHM: Kann SharedMemory nicht anbinden.");
+		}
+
+		SHM = NULL;
+		throw "Cannot attach SharedMemory";
+	}
+}
+
+static void DetachSHM(void){
+	if(SHM != NULL){
+		if(shmdt(SHM) == -1 && VerboseOutput){
+			puts("DetachSHM: Kann SharedMemory nicht löschen.");
+		}
+		SHM = NULL;
+	}
+}
+
+void InitSHM(bool Verbose){
+	IsGameServer = true;
+	VerboseOutput = Verbose;
+
+	CreateSHM();
+	AttachSHM();
+	SetErrorFunction(ErrorHandler);
+	SetPrintFunction(PrintHandler);
+
+	// NOTE(fusion): `CreateSHM` ensures a new shared memory segment is created
+	// and it should be always zero initialized as per the manual. Nevertheless
+	// the decompiled version was also clearing SHM, probably just in case.
+	memset(SHM, 0, sizeof(TSharedMemory));
+
+	strncpy(SHM->PrintBuffer[0], sizeof(SHM->PrintBuffer[0]),
+			"SHM initialized. System printing is working!\n");
+	SHM->PrintBuffer[0][sizeof(SHM->PrintBuffer[0]) - 1] = 0;
+
+	SHM->PrintBufferPosition = 1;
+	SHM->GameState = GAME_STARTING;
+	SHM->GameThreadPID = getpid();
+}
+
+void ExitSHM(void){
+	SetErrorFunction(NULL);
+	SetPrintFunction(NULL);
+	DetachSHM();
+	DeleteSHM();
+}
+
+void InitSHMExtern(bool Verbose){
+	VerboseOutput = Verbose;
+	AttachSHM();
+}
+
+void ExitSHMExtern(void){
+	DetachSHM();
+}