Support for Windows PuTTY connecting straight to a local serial port

[u/mdw/putty] / windows / winser.c

/*\r
 * Serial back end (Windows-specific).\r
 */\r
\r
/*\r
 * TODO:\r
 * \r
 *  - sending breaks?\r
 *     + looks as if you do this by calling SetCommBreak(handle),\r
 * 	 then waiting a bit, then doing ClearCommBreak(handle). A\r
 * 	 small job for timing.c, methinks.\r
 *\r
 *  - why are we dropping data when talking to judicator?\r
 */\r
\r
#include <stdio.h>\r
#include <stdlib.h>\r
#include <limits.h>\r
\r
#include "putty.h"\r
\r
#define SERIAL_MAX_BACKLOG 4096\r
\r
typedef struct serial_backend_data {\r
    HANDLE port;\r
    struct handle *out, *in;\r
    void *frontend;\r
    int bufsize;\r
} *Serial;\r
\r
static void serial_terminate(Serial serial)\r
{\r
    if (serial->out) {\r
	handle_free(serial->out);\r
	serial->out = NULL;\r
    }\r
    if (serial->in) {\r
	handle_free(serial->in);\r
	serial->in = NULL;\r
    }\r
    if (serial->port) {\r
	CloseHandle(serial->port);\r
	serial->port = NULL;\r
    }\r
}\r
\r
static int serial_gotdata(struct handle *h, void *data, int len)\r
{\r
    Serial serial = (Serial)handle_get_privdata(h);\r
    if (len <= 0) {\r
	const char *error_msg;\r
\r
	/*\r
	 * Currently, len==0 should never happen because we're\r
	 * ignoring EOFs. However, it seems not totally impossible\r
	 * that this same back end might be usable to talk to named\r
	 * pipes or some other non-serial device, in which case EOF\r
	 * may become meaningful here.\r
	 */\r
	if (len == 0)\r
	    error_msg = "End of file reading from serial device";\r
	else\r
	    error_msg = "Error reading from serial device";\r
\r
	serial_terminate(serial);\r
\r
	notify_remote_exit(serial->frontend);\r
\r
	logevent(serial->frontend, error_msg);\r
\r
	connection_fatal(serial->frontend, "%s", error_msg);\r
\r
	return 0;		       /* placate optimiser */\r
    } else {\r
	return from_backend(serial->frontend, 0, data, len);\r
    }\r
}\r
\r
static void serial_sentdata(struct handle *h, int new_backlog)\r
{\r
    Serial serial = (Serial)handle_get_privdata(h);\r
    if (new_backlog < 0) {\r
	const char *error_msg = "Error writing to serial device";\r
\r
	serial_terminate(serial);\r
\r
	notify_remote_exit(serial->frontend);\r
\r
	logevent(serial->frontend, error_msg);\r
\r
	connection_fatal(serial->frontend, "%s", error_msg);\r
    } else {\r
	serial->bufsize = new_backlog;\r
    }\r
}\r
\r
static const char *serial_configure(Serial serial, HANDLE serport, Config *cfg)\r
{\r
    DCB dcb;\r
    COMMTIMEOUTS timeouts;\r
\r
    /*\r
     * Set up the serial port parameters. If we can't even\r
     * GetCommState, we ignore the problem on the grounds that the\r
     * user might have pointed us at some other type of two-way\r
     * device instead of a serial port.\r
     */\r
    if (GetCommState(serport, &dcb)) {\r
	char *msg;\r
	const char *str;\r
\r
	/*\r
	 * Boilerplate.\r
	 */\r
	dcb.fBinary = TRUE;\r
	dcb.fDtrControl = DTR_CONTROL_ENABLE;\r
	dcb.fDsrSensitivity = FALSE;\r
	dcb.fTXContinueOnXoff = FALSE;\r
	dcb.fOutX = FALSE;\r
	dcb.fInX = FALSE;\r
	dcb.fErrorChar = FALSE;\r
	dcb.fNull = FALSE;\r
	dcb.fRtsControl = RTS_CONTROL_ENABLE;\r
	dcb.fAbortOnError = FALSE;\r
	dcb.fOutxCtsFlow = FALSE;\r
	dcb.fOutxDsrFlow = FALSE;\r
\r
	/*\r
	 * Configurable parameters.\r
	 */\r
	dcb.BaudRate = cfg->serspeed;\r
	msg = dupprintf("Configuring baud rate %d", cfg->serspeed);\r
	logevent(serial->frontend, msg);\r
	sfree(msg);\r
\r
	dcb.ByteSize = cfg->serdatabits;\r
	msg = dupprintf("Configuring %d data bits", cfg->serdatabits);\r
	logevent(serial->frontend, msg);\r
	sfree(msg);\r
\r
	switch (cfg->serstopbits) {\r
	  case 2: dcb.StopBits = ONESTOPBIT; str = "1"; break;\r
	  case 3: dcb.StopBits = ONE5STOPBITS; str = "1.5"; break;\r
	  case 4: dcb.StopBits = TWOSTOPBITS; str = "2"; break;\r
	  default: return "Invalid number of stop bits (need 1, 1.5 or 2)";\r
	}\r
	msg = dupprintf("Configuring %s data bits", str);\r
	logevent(serial->frontend, msg);\r
	sfree(msg);\r
\r
	switch (cfg->serparity) {\r
	  case SER_PAR_NONE: dcb.Parity = NOPARITY; str = "no"; break;\r
	  case SER_PAR_ODD: dcb.Parity = ODDPARITY; str = "odd"; break;\r
	  case SER_PAR_EVEN: dcb.Parity = EVENPARITY; str = "even"; break;\r
	  case SER_PAR_MARK: dcb.Parity = MARKPARITY; str = "mark"; break;\r
	  case SER_PAR_SPACE: dcb.Parity = SPACEPARITY; str = "space"; break;\r
	}\r
	msg = dupprintf("Configuring %s parity", str);\r
	logevent(serial->frontend, msg);\r
	sfree(msg);\r
\r
	switch (cfg->serflow) {\r
	  case SER_FLOW_NONE:\r
	    str = "no";\r
	    break;\r
	  case SER_FLOW_XONXOFF:\r
	    dcb.fOutX = dcb.fInX = TRUE;\r
	    str = "XON/XOFF";\r
	    break;\r
	  case SER_FLOW_RTSCTS:\r
	    dcb.fRtsControl = RTS_CONTROL_HANDSHAKE;\r
	    dcb.fOutxCtsFlow = TRUE;\r
	    str = "RTS/CTS";\r
	    break;\r
	  case SER_FLOW_DSRDTR:\r
	    dcb.fDtrControl = DTR_CONTROL_HANDSHAKE;\r
	    dcb.fOutxDsrFlow = TRUE;\r
	    str = "DSR/DTR";\r
	    break;\r
	}\r
	msg = dupprintf("Configuring %s flow control", str);\r
	logevent(serial->frontend, msg);\r
	sfree(msg);\r
\r
	if (!SetCommState(serport, &dcb))\r
	    return "Unable to configure serial port";\r
\r
	timeouts.ReadIntervalTimeout = 1;\r
	timeouts.ReadTotalTimeoutMultiplier = 0;\r
	timeouts.ReadTotalTimeoutConstant = 0;\r
	timeouts.WriteTotalTimeoutMultiplier = 0;\r
	timeouts.WriteTotalTimeoutConstant = 0;\r
	if (!SetCommTimeouts(serport, &timeouts))\r
	    return "Unable to configure serial timeouts";\r
    }\r
\r
    return NULL;\r
}\r
\r
/*\r
 * Called to set up the serial connection.\r
 * \r
 * Returns an error message, or NULL on success.\r
 *\r
 * Also places the canonical host name into `realhost'. It must be\r
 * freed by the caller.\r
 */\r
static const char *serial_init(void *frontend_handle, void **backend_handle,\r
			       Config *cfg,\r
			       char *host, int port, char **realhost, int nodelay,\r
			       int keepalive)\r
{\r
    Serial serial;\r
    HANDLE serport;\r
    const char *err;\r
\r
    serial = snew(struct serial_backend_data);\r
    serial->port = NULL;\r
    serial->out = serial->in = NULL;\r
    *backend_handle = serial;\r
\r
    serial->frontend = frontend_handle;\r
\r
    {\r
	char *msg = dupprintf("Opening serial device %s", host);\r
	logevent(serial->frontend, msg);\r
    }\r
\r
    serport = CreateFile(cfg->serline, GENERIC_READ | GENERIC_WRITE, 0, NULL,\r
			 OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);\r
    if (serport == INVALID_HANDLE_VALUE)\r
	return "Unable to open serial port";\r
\r
    err = serial_configure(serial, serport, cfg);\r
    if (err)\r
	return err;\r
\r
    serial->port = serport;\r
    serial->out = handle_output_new(serport, serial_sentdata, serial,\r
				    HANDLE_FLAG_OVERLAPPED);\r
    serial->in = handle_input_new(serport, serial_gotdata, serial,\r
				  HANDLE_FLAG_OVERLAPPED |\r
				  HANDLE_FLAG_IGNOREEOF);\r
\r
    *realhost = dupstr(cfg->serline);\r
\r
    return NULL;\r
}\r
\r
static void serial_free(void *handle)\r
{\r
    Serial serial = (Serial) handle;\r
\r
    serial_terminate(serial);\r
    sfree(serial);\r
}\r
\r
static void serial_reconfig(void *handle, Config *cfg)\r
{\r
    Serial serial = (Serial) handle;\r
    const char *err;\r
\r
    err = serial_configure(serial, serial->port, cfg);\r
\r
    /*\r
     * FIXME: what should we do if err returns something?\r
     */\r
}\r
\r
/*\r
 * Called to send data down the serial connection.\r
 */\r
static int serial_send(void *handle, char *buf, int len)\r
{\r
    Serial serial = (Serial) handle;\r
\r
    if (serial->out == NULL)\r
	return 0;\r
\r
    serial->bufsize = handle_write(serial->out, buf, len);\r
    return serial->bufsize;\r
}\r
\r
/*\r
 * Called to query the current sendability status.\r
 */\r
static int serial_sendbuffer(void *handle)\r
{\r
    Serial serial = (Serial) handle;\r
    return serial->bufsize;\r
}\r
\r
/*\r
 * Called to set the size of the window\r
 */\r
static void serial_size(void *handle, int width, int height)\r
{\r
    /* Do nothing! */\r
    return;\r
}\r
\r
/*\r
 * Send serial special codes.\r
 */\r
static void serial_special(void *handle, Telnet_Special code)\r
{\r
    /*\r
     * FIXME: serial break? XON? XOFF?\r
     */\r
    return;\r
}\r
\r
/*\r
 * Return a list of the special codes that make sense in this\r
 * protocol.\r
 */\r
static const struct telnet_special *serial_get_specials(void *handle)\r
{\r
    /*\r
     * FIXME: serial break? XON? XOFF?\r
     */\r
    return NULL;\r
}\r
\r
static int serial_connected(void *handle)\r
{\r
    return 1;			       /* always connected */\r
}\r
\r
static int serial_sendok(void *handle)\r
{\r
    return 1;\r
}\r
\r
static void serial_unthrottle(void *handle, int backlog)\r
{\r
    Serial serial = (Serial) handle;\r
    if (serial->in)\r
	handle_unthrottle(serial->in, backlog);\r
}\r
\r
static int serial_ldisc(void *handle, int option)\r
{\r
    /*\r
     * Local editing and local echo are off by default.\r
     */\r
    return 0;\r
}\r
\r
static void serial_provide_ldisc(void *handle, void *ldisc)\r
{\r
    /* This is a stub. */\r
}\r
\r
static void serial_provide_logctx(void *handle, void *logctx)\r
{\r
    /* This is a stub. */\r
}\r
\r
static int serial_exitcode(void *handle)\r
{\r
    Serial serial = (Serial) handle;\r
    if (serial->port != NULL)\r
        return -1;                     /* still connected */\r
    else\r
        /* Exit codes are a meaningless concept with serial ports */\r
        return INT_MAX;\r
}\r
\r
/*\r
 * cfg_info for Serial does nothing at all.\r
 */\r
static int serial_cfg_info(void *handle)\r
{\r
    return 0;\r
}\r
\r
Backend serial_backend = {\r
    serial_init,\r
    serial_free,\r
    serial_reconfig,\r
    serial_send,\r
    serial_sendbuffer,\r
    serial_size,\r
    serial_special,\r
    serial_get_specials,\r
    serial_connected,\r
    serial_exitcode,\r
    serial_sendok,\r
    serial_ldisc,\r
    serial_provide_ldisc,\r
    serial_provide_logctx,\r
    serial_unthrottle,\r
    serial_cfg_info,\r
    1\r
};\r