Disable a bunch of undesirable termios flags. ICRNL, in particular,
[u/mdw/putty] / unix / uxser.c
1 /*
2 * Serial back end (Unix-specific).
3 */
4
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <assert.h>
8 #include <limits.h>
9
10 #include <errno.h>
11 #include <unistd.h>
12 #include <fcntl.h>
13 #include <termios.h>
14
15 #include "putty.h"
16 #include "tree234.h"
17
18 #define SERIAL_MAX_BACKLOG 4096
19
20 typedef struct serial_backend_data {
21 void *frontend;
22 int fd;
23 int finished;
24 int inbufsize;
25 bufchain output_data;
26 } *Serial;
27
28 /*
29 * We store our serial backends in a tree sorted by fd, so that
30 * when we get an uxsel notification we know which backend instance
31 * is the owner of the serial port that caused it.
32 */
33 static int serial_compare_by_fd(void *av, void *bv)
34 {
35 Serial a = (Serial)av;
36 Serial b = (Serial)bv;
37
38 if (a->fd < b->fd)
39 return -1;
40 else if (a->fd > b->fd)
41 return +1;
42 return 0;
43 }
44
45 static int serial_find_by_fd(void *av, void *bv)
46 {
47 int a = *(int *)av;
48 Serial b = (Serial)bv;
49
50 if (a < b->fd)
51 return -1;
52 else if (a > b->fd)
53 return +1;
54 return 0;
55 }
56
57 static tree234 *serial_by_fd = NULL;
58
59 static int serial_select_result(int fd, int event);
60 static void serial_uxsel_setup(Serial serial);
61 static void serial_try_write(Serial serial);
62
63 static const char *serial_configure(Serial serial, Config *cfg)
64 {
65 struct termios options;
66 int bflag, bval;
67 const char *str;
68 char *msg;
69
70 if (serial->fd < 0)
71 return "Unable to reconfigure already-closed serial connection";
72
73 tcgetattr(serial->fd, &options);
74
75 /*
76 * Find the appropriate baud rate flag.
77 */
78 #define SETBAUD(x) (bflag = B ## x, bval = x)
79 #define CHECKBAUD(x) do { if (cfg->serspeed >= x) SETBAUD(x); } while (0)
80 SETBAUD(50);
81 #ifdef B75
82 CHECKBAUD(75);
83 #endif
84 #ifdef B110
85 CHECKBAUD(110);
86 #endif
87 #ifdef B134
88 CHECKBAUD(134);
89 #endif
90 #ifdef B150
91 CHECKBAUD(150);
92 #endif
93 #ifdef B200
94 CHECKBAUD(200);
95 #endif
96 #ifdef B300
97 CHECKBAUD(300);
98 #endif
99 #ifdef B600
100 CHECKBAUD(600);
101 #endif
102 #ifdef B1200
103 CHECKBAUD(1200);
104 #endif
105 #ifdef B1800
106 CHECKBAUD(1800);
107 #endif
108 #ifdef B2400
109 CHECKBAUD(2400);
110 #endif
111 #ifdef B4800
112 CHECKBAUD(4800);
113 #endif
114 #ifdef B9600
115 CHECKBAUD(9600);
116 #endif
117 #ifdef B19200
118 CHECKBAUD(19200);
119 #endif
120 #ifdef B38400
121 CHECKBAUD(38400);
122 #endif
123 #ifdef B57600
124 CHECKBAUD(57600);
125 #endif
126 #ifdef B76800
127 CHECKBAUD(76800);
128 #endif
129 #ifdef B115200
130 CHECKBAUD(115200);
131 #endif
132 #ifdef B230400
133 CHECKBAUD(230400);
134 #endif
135 #undef CHECKBAUD
136 #undef SETBAUD
137 cfsetispeed(&options, bflag);
138 cfsetospeed(&options, bflag);
139 msg = dupprintf("Configuring baud rate %d", bval);
140 logevent(serial->frontend, msg);
141 sfree(msg);
142
143 options.c_cflag &= ~CSIZE;
144 switch (cfg->serdatabits) {
145 case 5: options.c_cflag |= CS5; break;
146 case 6: options.c_cflag |= CS6; break;
147 case 7: options.c_cflag |= CS7; break;
148 case 8: options.c_cflag |= CS8; break;
149 default: return "Invalid number of data bits (need 5, 6, 7 or 8)";
150 }
151 msg = dupprintf("Configuring %d data bits", cfg->serdatabits);
152 logevent(serial->frontend, msg);
153 sfree(msg);
154
155 if (cfg->serstopbits >= 4) {
156 options.c_cflag |= CSTOPB;
157 } else {
158 options.c_cflag &= ~CSTOPB;
159 }
160 msg = dupprintf("Configuring %d stop bits",
161 (options.c_cflag & CSTOPB ? 2 : 1));
162 logevent(serial->frontend, msg);
163 sfree(msg);
164
165 options.c_iflag &= ~(IXON|IXOFF);
166 #ifdef CRTSCTS
167 options.c_cflag &= ~CRTSCTS;
168 #endif
169 #ifdef CNEW_RTSCTS
170 options.c_cflag &= ~CNEW_RTSCTS;
171 #endif
172 if (cfg->serflow == SER_FLOW_XONXOFF) {
173 options.c_iflag |= IXON | IXOFF;
174 str = "XON/XOFF";
175 } else if (cfg->serflow == SER_FLOW_RTSCTS) {
176 #ifdef CRTSCTS
177 options.c_cflag |= CRTSCTS;
178 #endif
179 #ifdef CNEW_RTSCTS
180 options.c_cflag |= CNEW_RTSCTS;
181 #endif
182 str = "RTS/CTS";
183 } else
184 str = "no";
185 msg = dupprintf("Configuring %s flow control", str);
186 logevent(serial->frontend, msg);
187 sfree(msg);
188
189 /* Parity */
190 if (cfg->serparity == SER_PAR_ODD) {
191 options.c_cflag |= PARENB;
192 options.c_cflag |= PARODD;
193 str = "odd";
194 } else if (cfg->serparity == SER_PAR_EVEN) {
195 options.c_cflag |= PARENB;
196 options.c_cflag &= ~PARODD;
197 str = "even";
198 } else {
199 options.c_cflag &= ~PARENB;
200 str = "no";
201 }
202 msg = dupprintf("Configuring %s parity", str);
203 logevent(serial->frontend, msg);
204 sfree(msg);
205
206 options.c_cflag |= CLOCAL | CREAD;
207 options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
208 options.c_iflag &= ~(ISTRIP | IGNCR | INLCR | ICRNL
209 #ifdef IUCLC
210 | IUCLC
211 #endif
212 );
213 options.c_oflag &= ~(OPOST
214 #ifdef ONLCR
215 | ONLCR
216 #endif
217 | OCRNL | ONOCR | ONLRET);
218 options.c_cc[VMIN] = 1;
219 options.c_cc[VTIME] = 0;
220
221 if (tcsetattr(serial->fd, TCSANOW, &options) < 0)
222 return "Unable to configure serial port";
223
224 return NULL;
225 }
226
227 /*
228 * Called to set up the serial connection.
229 *
230 * Returns an error message, or NULL on success.
231 *
232 * Also places the canonical host name into `realhost'. It must be
233 * freed by the caller.
234 */
235 static const char *serial_init(void *frontend_handle, void **backend_handle,
236 Config *cfg,
237 char *host, int port, char **realhost, int nodelay,
238 int keepalive)
239 {
240 Serial serial;
241 const char *err;
242
243 serial = snew(struct serial_backend_data);
244 *backend_handle = serial;
245
246 serial->frontend = frontend_handle;
247 serial->finished = FALSE;
248 serial->inbufsize = 0;
249 bufchain_init(&serial->output_data);
250
251 {
252 char *msg = dupprintf("Opening serial device %s", cfg->serline);
253 logevent(serial->frontend, msg);
254 }
255
256 serial->fd = open(cfg->serline, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK);
257 if (serial->fd < 0)
258 return "Unable to open serial port";
259
260 err = serial_configure(serial, cfg);
261 if (err)
262 return err;
263
264 *realhost = dupstr(cfg->serline);
265
266 if (!serial_by_fd)
267 serial_by_fd = newtree234(serial_compare_by_fd);
268 add234(serial_by_fd, serial);
269
270 serial_uxsel_setup(serial);
271
272 /*
273 * Specials are always available.
274 */
275 update_specials_menu(serial->frontend);
276
277 return NULL;
278 }
279
280 static void serial_close(Serial serial)
281 {
282 if (serial->fd >= 0) {
283 close(serial->fd);
284 serial->fd = -1;
285 }
286 }
287
288 static void serial_free(void *handle)
289 {
290 Serial serial = (Serial) handle;
291
292 serial_close(serial);
293
294 bufchain_clear(&serial->output_data);
295
296 sfree(serial);
297 }
298
299 static void serial_reconfig(void *handle, Config *cfg)
300 {
301 Serial serial = (Serial) handle;
302 const char *err;
303
304 err = serial_configure(serial, cfg);
305
306 /*
307 * FIXME: what should we do if err returns something?
308 */
309 }
310
311 static int serial_select_result(int fd, int event)
312 {
313 Serial serial;
314 char buf[4096];
315 int ret;
316 int finished = FALSE;
317
318 serial = find234(serial_by_fd, &fd, serial_find_by_fd);
319
320 if (!serial)
321 return 1; /* spurious event; keep going */
322
323 if (event == 1) {
324 ret = read(serial->fd, buf, sizeof(buf));
325
326 if (ret == 0) {
327 /*
328 * Shouldn't happen on a real serial port, but I'm open
329 * to the idea that there might be two-way devices we
330 * can treat _like_ serial ports which can return EOF.
331 */
332 finished = TRUE;
333 } else if (ret < 0) {
334 perror("read serial port");
335 exit(1);
336 } else if (ret > 0) {
337 serial->inbufsize = from_backend(serial->frontend, 0, buf, ret);
338 serial_uxsel_setup(serial); /* might acquire backlog and freeze */
339 }
340 } else if (event == 2) {
341 /*
342 * Attempt to send data down the pty.
343 */
344 serial_try_write(serial);
345 }
346
347 if (finished) {
348 serial_close(serial);
349
350 serial->finished = TRUE;
351
352 notify_remote_exit(serial->frontend);
353 }
354
355 return !finished;
356 }
357
358 static void serial_uxsel_setup(Serial serial)
359 {
360 int rwx = 0;
361
362 if (serial->inbufsize <= SERIAL_MAX_BACKLOG)
363 rwx |= 1;
364 if (bufchain_size(&serial->output_data))
365 rwx |= 2; /* might also want to write to it */
366 uxsel_set(serial->fd, rwx, serial_select_result);
367 }
368
369 static void serial_try_write(Serial serial)
370 {
371 void *data;
372 int len, ret;
373
374 assert(serial->fd >= 0);
375
376 while (bufchain_size(&serial->output_data) > 0) {
377 bufchain_prefix(&serial->output_data, &data, &len);
378 ret = write(serial->fd, data, len);
379
380 if (ret < 0 && (errno == EWOULDBLOCK)) {
381 /*
382 * We've sent all we can for the moment.
383 */
384 break;
385 }
386 if (ret < 0) {
387 perror("write serial port");
388 exit(1);
389 }
390 bufchain_consume(&serial->output_data, ret);
391 }
392
393 serial_uxsel_setup(serial);
394 }
395
396 /*
397 * Called to send data down the serial connection.
398 */
399 static int serial_send(void *handle, char *buf, int len)
400 {
401 Serial serial = (Serial) handle;
402
403 if (serial->fd < 0)
404 return 0;
405
406 bufchain_add(&serial->output_data, buf, len);
407 serial_try_write(serial);
408
409 return bufchain_size(&serial->output_data);
410 }
411
412 /*
413 * Called to query the current sendability status.
414 */
415 static int serial_sendbuffer(void *handle)
416 {
417 Serial serial = (Serial) handle;
418 return bufchain_size(&serial->output_data);
419 }
420
421 /*
422 * Called to set the size of the window
423 */
424 static void serial_size(void *handle, int width, int height)
425 {
426 /* Do nothing! */
427 return;
428 }
429
430 /*
431 * Send serial special codes.
432 */
433 static void serial_special(void *handle, Telnet_Special code)
434 {
435 Serial serial = (Serial) handle;
436
437 if (serial->fd >= 0 && code == TS_BRK) {
438 tcsendbreak(serial->fd, 0);
439 logevent(serial->frontend, "Sending serial break at user request");
440 }
441
442 return;
443 }
444
445 /*
446 * Return a list of the special codes that make sense in this
447 * protocol.
448 */
449 static const struct telnet_special *serial_get_specials(void *handle)
450 {
451 static const struct telnet_special specials[] = {
452 {"Break", TS_BRK},
453 {NULL, TS_EXITMENU}
454 };
455 return specials;
456 }
457
458 static int serial_connected(void *handle)
459 {
460 return 1; /* always connected */
461 }
462
463 static int serial_sendok(void *handle)
464 {
465 return 1;
466 }
467
468 static void serial_unthrottle(void *handle, int backlog)
469 {
470 Serial serial = (Serial) handle;
471 serial->inbufsize = backlog;
472 serial_uxsel_setup(serial);
473 }
474
475 static int serial_ldisc(void *handle, int option)
476 {
477 /*
478 * Local editing and local echo are off by default.
479 */
480 return 0;
481 }
482
483 static void serial_provide_ldisc(void *handle, void *ldisc)
484 {
485 /* This is a stub. */
486 }
487
488 static void serial_provide_logctx(void *handle, void *logctx)
489 {
490 /* This is a stub. */
491 }
492
493 static int serial_exitcode(void *handle)
494 {
495 Serial serial = (Serial) handle;
496 if (serial->fd >= 0)
497 return -1; /* still connected */
498 else
499 /* Exit codes are a meaningless concept with serial ports */
500 return INT_MAX;
501 }
502
503 /*
504 * cfg_info for Serial does nothing at all.
505 */
506 static int serial_cfg_info(void *handle)
507 {
508 return 0;
509 }
510
511 Backend serial_backend = {
512 serial_init,
513 serial_free,
514 serial_reconfig,
515 serial_send,
516 serial_sendbuffer,
517 serial_size,
518 serial_special,
519 serial_get_specials,
520 serial_connected,
521 serial_exitcode,
522 serial_sendok,
523 serial_ldisc,
524 serial_provide_ldisc,
525 serial_provide_logctx,
526 serial_unthrottle,
527 serial_cfg_info,
528 1
529 };