New VDD function: hangup (disconnect) for "drop DTR" support in FOSSIL driver

and virtual UART VDD.
New hangup named event, for VDD to use to disconnect socket at program's
request (dropped DTR).

src/sbbs3/sbbsexec.c

@@ -71,6 +71,8 @@ BYTE uart_divisor_latch_msb		= 0x00;
 
 BOOL		virtualize_uart=TRUE;
 double		yield_interval=1.0;
+BOOL		hangup_supported=TRUE;
+HANDLE		hangup_event=NULL;
 HANDLE		hungup_event=NULL;
 HANDLE		interrupt_event=NULL;
 HANDLE		rdslot=INVALID_HANDLE_VALUE;
@@ -106,6 +108,14 @@ static void lprintf(int level, const char *fmt, ...)
     lputs(level,sbuf);
 }
 
+void hangup()
+{
+	if(hangup_supported && hangup_event!=NULL) {
+		lprintf(LOG_DEBUG,"Hanging-up at application request");
+		SetEvent(hangup_event);
+	}
+}
+
 void parse_ini(char* program)
 {
 	char section[MAX_PATH+1];
@@ -118,6 +128,7 @@ void parse_ini(char* program)
 	if(iniGetBool(ini,program,"Debug",FALSE))
 		log_level=LOG_DEBUG;
 	yield_interval=iniGetFloat(ini,program,"YieldInterval",yield_interval);
+	hangup_supported=iniGetBool(ini,program,"CanDisconnect",hangup_supported);
 
 	lprintf(LOG_INFO,"Parsed %s section of %s"
 		,program==ROOT_SECTION ? "root" : program
@@ -322,6 +333,8 @@ VOID uart_wrport(WORD port, BYTE data)
 			break;
 		case UART_MCR:
 			uart_mcr_reg = data;
+			if((uart_mcr_reg&UART_MSR_DCD) == 0)
+				hangup();
 			break;
 		case UART_SCRATCH:
 			uart_scratch_reg = data;
@@ -506,6 +519,18 @@ __declspec(dllexport) void __cdecl VDDDispatch(void)
 				break;
 			}
 
+			sprintf(str,"sbbsexec_hangup%d",node_num);
+			hangup_event=OpenEvent(
+				EVENT_ALL_ACCESS,	/* access flag  */
+				FALSE,				/* inherit flag  */
+				str);				/* pointer to event-object name  */
+			if(hangup_event==NULL) {
+				lprintf(LOG_ERR,"!VDD_OPEN: Error %d opening %s"
+					,GetLastError(),str);
+				retval=4;
+				break;
+			}
+
 			status_poll=0;
 			inbuf_poll=0;
 			online_poll=0;
@@ -554,6 +579,9 @@ __declspec(dllexport) void __cdecl VDDDispatch(void)
 			CloseHandle(wrslot);
 			if(hungup_event!=NULL)
 				CloseHandle(hungup_event);
+			if(hangup_event!=NULL)
+				CloseHandle(hangup_event);
+
 			RingBufDispose(&rdbuf);
 			status_poll=0;
 			retval=0;
@@ -740,6 +768,10 @@ __declspec(dllexport) void __cdecl VDDDispatch(void)
 			lputs(LOG_INFO, p);
 			break;
 
+		case VDD_HANGUP:
+			hangup();
+			break;
+
 		default:
 			lprintf(LOG_ERR,"!UNKNOWN VDD_OP: %d",getBL());
 			break;

src/sbbs3/xtrn.cpp

@@ -351,6 +351,7 @@ static void add_env_var(str_list_t* list, const char* var, const char* val)
 	if(wrslot!=INVALID_HANDLE_VALUE)	CloseHandle(wrslot);		\
 	if(start_event!=NULL)				CloseHandle(start_event);	\
 	if(hungup_event!=NULL)				CloseHandle(hungup_event);	\
+	if(hangup_event!=NULL)				CloseHandle(hangup_event);	\
 	ReleaseMutex(exec_mutex);										\
 	SetLastError(last_error)
 
@@ -388,6 +389,7 @@ int sbbs_t::external(const char* cmdline, long mode, const char* startup_dir)
 	HANDLE	wrslot=INVALID_HANDLE_VALUE;
 	HANDLE  start_event=NULL;
 	HANDLE	hungup_event=NULL;
+	HANDLE	hangup_event=NULL;
 	HANDLE	rdoutpipe;
 	HANDLE	wrinpipe;
     PROCESS_INFORMATION process_info;
@@ -542,6 +544,18 @@ int sbbs_t::external(const char* cmdline, long mode, const char* startup_dir)
 				return(GetLastError());
 			}
 
+			sprintf(str,"sbbsexec_hangup%d",cfg.node_num);
+			if((hangup_event=CreateEvent(
+				 NULL	// pointer to security attributes
+				,TRUE	// flag for manual-reset event
+				,FALSE  // flag for initial state
+				,str	// pointer to event-object name
+				))==NULL) {
+				XTRN_CLEANUP;
+				errormsg(WHERE, ERR_CREATE, str, 0);
+				return(GetLastError());
+			}
+
 			sprintf(str,"\\\\.\\mailslot\\sbbsexec\\rd%d"
 				,cfg.node_num);
 			rdslot=CreateMailslot(str
@@ -976,9 +990,18 @@ int sbbs_t::external(const char* cmdline, long mode, const char* startup_dir)
 
 				/* only check process termination after 300 milliseconds of no I/O */
 				/* to allow for last minute reception of output from DOS programs */
-				if(loop_since_io>=3
-					&& WaitForSingleObject(process_info.hProcess,0)==WAIT_OBJECT_0)
-					break;	/* Process Terminated */
+				if(loop_since_io>=3) {
+
+					if(hangup_event!=NULL
+						&& WaitForSingleObject(hangup_event,0)==WAIT_OBJECT_0) {
+						lprintf(LOG_NOTICE,"Node %d External program requested hangup (dropped DTR)"
+							,cfg.node_num);
+						hangup();
+					}
+
+					if(WaitForSingleObject(process_info.hProcess,0)==WAIT_OBJECT_0)
+						break;	/* Process Terminated */
+				}
 
 				/* only check node for interrupt flag every 3 seconds of no I/O */
 				if((loop_since_io%30)==0) {