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serial: Changed order of flags PARENB and PARODD in deletion to same order as in...
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1/*
2 * This file is part of the libsigrok project.
3 *
4 * Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
5 * Copyright (C) 2010-2012 Uwe Hermann <uwe@hermann-uwe.de>
6 * Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
7 *
8 * This program is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22#include <string.h>
23#include <sys/types.h>
24#include <sys/stat.h>
25#include <fcntl.h>
26#include <unistd.h>
27#ifdef _WIN32
28#include <windows.h>
29#else
30#include <termios.h>
31#include <sys/ioctl.h>
32#endif
33#include <stdlib.h>
34#include <errno.h>
35#include <glib.h>
36#include "libsigrok.h"
37#include "libsigrok-internal.h"
38
39/* Message logging helpers with subsystem-specific prefix string. */
40#define LOG_PREFIX "serial: "
41#define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
42#define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
43#define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
44#define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
45#define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
46#define sr_err(s, args...) sr_err(LOG_PREFIX s, ## args)
47
48// FIXME: Must be moved, or rather passed as function argument.
49#ifdef _WIN32
50static HANDLE hdl;
51#endif
52
53/**
54 * Open the specified serial port.
55 *
56 * @param serial Previously initialized serial port structure.
57 * @param flags Flags to use when opening the serial port. Possible flags
58 * include SERIAL_RDWR, SERIAL_RDONLY, SERIAL_NONBLOCK.
59 *
60 * If the serial structure contains a serialcomm string, it will be
61 * passed to serial_set_paramstr() after the port is opened.
62 *
63 * @return SR_OK on success, SR_ERR on failure.
64 */
65SR_PRIV int serial_open(struct sr_serial_dev_inst *serial, int flags)
66{
67 int flags_local = 0;
68#ifdef _WIN32
69 DWORD desired_access = 0, flags_and_attributes = 0;
70#endif
71
72 if (!serial) {
73 sr_dbg("Invalid serial port.");
74 return SR_ERR;
75 }
76
77 sr_spew("Opening serial port '%s' (flags %d).", serial->port, flags);
78
79#ifdef _WIN32
80 /* Map 'flags' to the OS-specific settings. */
81 desired_access |= GENERIC_READ;
82 flags_and_attributes = FILE_ATTRIBUTE_NORMAL;
83 if (flags & SERIAL_RDWR)
84 desired_access |= GENERIC_WRITE;
85 if (flags & SERIAL_NONBLOCK)
86 flags_and_attributes |= FILE_FLAG_OVERLAPPED;
87
88 hdl = CreateFile(serial->port, desired_access, 0, 0,
89 OPEN_EXISTING, flags_and_attributes, 0);
90 if (hdl == INVALID_HANDLE_VALUE) {
91 sr_err("Error opening serial port '%s'.", serial->port);
92 return SR_ERR;
93 }
94#else
95 /* Map 'flags' to the OS-specific settings. */
96 if (flags & SERIAL_RDWR)
97 flags_local |= O_RDWR;
98 if (flags & SERIAL_RDONLY)
99 flags_local |= O_RDONLY;
100 if (flags & SERIAL_NONBLOCK)
101 flags_local |= O_NONBLOCK;
102
103 if ((serial->fd = open(serial->port, flags_local)) < 0) {
104 sr_err("Error opening serial port '%s': %s.", serial->port,
105 strerror(errno));
106 return SR_ERR;
107 }
108
109 sr_spew("Opened serial port '%s' (fd %d).", serial->port, serial->fd);
110#endif
111
112 if (serial->serialcomm)
113 return serial_set_paramstr(serial, serial->serialcomm);
114 else
115 return SR_OK;
116}
117
118/**
119 * Close the specified serial port.
120 *
121 * @param serial Previously initialized serial port structure.
122 *
123 * @return SR_OK on success, SR_ERR on failure.
124 */
125SR_PRIV int serial_close(struct sr_serial_dev_inst *serial)
126{
127 int ret;
128
129 if (!serial) {
130 sr_dbg("Invalid serial port.");
131 return SR_ERR;
132 }
133
134 if (serial->fd == -1) {
135 sr_dbg("Cannot close unopened serial port %s (fd %d).",
136 serial->port, serial->fd);
137 return SR_ERR;
138 }
139
140 sr_spew("Closing serial port %s (fd %d).", serial->port, serial->fd);
141 ret = SR_OK;
142
143#ifdef _WIN32
144 /* Returns non-zero upon success, 0 upon failure. */
145 if (CloseHandle(hdl) == 0)
146 ret = SR_ERR;
147#else
148 /* Returns 0 upon success, -1 upon failure. */
149 if (close(serial->fd) < 0) {
150 sr_err("Error closing serial port: %s (fd %d).", strerror(errno),
151 serial->fd);
152 ret = SR_ERR;
153 }
154#endif
155
156 serial->fd = -1;
157
158 return ret;
159}
160
161/**
162 * Flush serial port buffers.
163 *
164 * @param serial Previously initialized serial port structure.
165 *
166 * @return SR_OK on success, SR_ERR on failure.
167 */
168SR_PRIV int serial_flush(struct sr_serial_dev_inst *serial)
169{
170 int ret;
171
172 if (!serial) {
173 sr_dbg("Invalid serial port.");
174 return SR_ERR;
175 }
176
177 if (serial->fd == -1) {
178 sr_dbg("Cannot flush unopened serial port %s (fd %d).",
179 serial->port, serial->fd);
180 return SR_ERR;
181 }
182
183 sr_spew("Flushing serial port %s (fd %d).", serial->port, serial->fd);
184 ret = SR_OK;
185
186#ifdef _WIN32
187 /* Returns non-zero upon success, 0 upon failure. */
188 if (PurgeComm(hdl, PURGE_RXCLEAR | PURGE_TXCLEAR) == 0) {
189 sr_err("Error flushing serial port: %s.", strerror(errno));
190 ret = SR_ERR;
191 }
192#else
193 /* Returns 0 upon success, -1 upon failure. */
194 if (tcflush(serial->fd, TCIOFLUSH) < 0) {
195 sr_err("Error flushing serial port: %s.", strerror(errno));
196 ret = SR_ERR;
197 }
198
199 return ret;
200#endif
201}
202
203/**
204 * Write a number of bytes to the specified serial port.
205 *
206 * @param serial Previously initialized serial port structure.
207 * @param buf Buffer containing the bytes to write.
208 * @param count Number of bytes to write.
209 *
210 * @return The number of bytes written, or -1 upon failure.
211 */
212SR_PRIV int serial_write(struct sr_serial_dev_inst *serial,
213 const void *buf, size_t count)
214{
215 ssize_t ret;
216
217 if (!serial) {
218 sr_dbg("Invalid serial port.");
219 return -1;
220 }
221
222 if (serial->fd == -1) {
223 sr_dbg("Cannot use unopened serial port %s (fd %d).",
224 serial->port, serial->fd);
225 return -1;
226 }
227
228#ifdef _WIN32
229 DWORD tmp = 0;
230
231 /* FIXME */
232 /* Returns non-zero upon success, 0 upon failure. */
233 WriteFile(hdl, buf, count, &tmp, NULL);
234#else
235 /* Returns the number of bytes written, or -1 upon failure. */
236 ret = write(serial->fd, buf, count);
237 if (ret < 0)
238 sr_err("Write error: %s.", strerror(errno));
239 else
240 sr_spew("Wrote %d/%d bytes (fd %d).", ret, count, serial->fd);
241#endif
242
243 return ret;
244}
245
246/**
247 * Read a number of bytes from the specified serial port.
248 *
249 * @param serial Previously initialized serial port structure.
250 * @param buf Buffer where to store the bytes that are read.
251 * @param count The number of bytes to read.
252 *
253 * @return The number of bytes read, or -1 upon failure.
254 */
255SR_PRIV int serial_read(struct sr_serial_dev_inst *serial, void *buf,
256 size_t count)
257{
258 ssize_t ret;
259
260 if (!serial) {
261 sr_dbg("Invalid serial port.");
262 return -1;
263 }
264
265 if (serial->fd == -1) {
266 sr_dbg("Cannot use unopened serial port %s (fd %d).",
267 serial->port, serial->fd);
268 return -1;
269 }
270
271#ifdef _WIN32
272 DWORD tmp = 0;
273
274 /* FIXME */
275 /* Returns non-zero upon success, 0 upon failure. */
276 return ReadFile(hdl, buf, count, &tmp, NULL);
277#else
278 /* Returns the number of bytes read, or -1 upon failure. */
279 ret = read(serial->fd, buf, count);
280#endif
281
282 return ret;
283}
284
285/**
286 * Set serial parameters for the specified serial port.
287 *
288 * @param serial Previously initialized serial port structure.
289 * @param baudrate The baudrate to set.
290 * @param bits The number of data bits to use.
291 * @param parity The parity setting to use (0 = none, 1 = even, 2 = odd).
292 * @param stopbits The number of stop bits to use (1 or 2).
293 * @param flowcontrol The flow control settings to use (0 = none, 1 = RTS/CTS,
294 * 2 = XON/XOFF).
295 *
296 * @return SR_OK upon success, SR_ERR upon failure.
297 */
298SR_PRIV int serial_set_params(struct sr_serial_dev_inst *serial, int baudrate,
299 int bits, int parity, int stopbits,
300 int flowcontrol, int rts, int dtr)
301{
302 if (!serial) {
303 sr_dbg("Invalid serial port.");
304 return SR_ERR;
305 }
306
307 if (serial->fd == -1) {
308 sr_dbg("Cannot configure unopened serial port %s (fd %d).",
309 serial->port, serial->fd);
310 return SR_ERR;
311 }
312
313 sr_spew("Setting serial parameters on port %s (fd %d).", serial->port,
314 serial->fd);
315
316#ifdef _WIN32
317 DCB dcb;
318
319 if (!GetCommState(hdl, &dcb)) {
320 sr_err("Failed to get comm state on port %s (fd %d): %d.",
321 serial->port, serial->fd, GetLastError());
322 return SR_ERR;
323 }
324
325 switch (baudrate) {
326 /*
327 * The baudrates 50/75/134/150/200/1800/230400/460800 do not seem to
328 * have documented CBR_* macros.
329 */
330 case 110:
331 dcb.BaudRate = CBR_110;
332 break;
333 case 300:
334 dcb.BaudRate = CBR_300;
335 break;
336 case 600:
337 dcb.BaudRate = CBR_600;
338 break;
339 case 1200:
340 dcb.BaudRate = CBR_1200;
341 break;
342 case 2400:
343 dcb.BaudRate = CBR_2400;
344 break;
345 case 4800:
346 dcb.BaudRate = CBR_4800;
347 break;
348 case 9600:
349 dcb.BaudRate = CBR_9600;
350 break;
351 case 14400:
352 dcb.BaudRate = CBR_14400; /* Not available on Unix? */
353 break;
354 case 19200:
355 dcb.BaudRate = CBR_19200;
356 break;
357 case 38400:
358 dcb.BaudRate = CBR_38400;
359 break;
360 case 57600:
361 dcb.BaudRate = CBR_57600;
362 break;
363 case 115200:
364 dcb.BaudRate = CBR_115200;
365 break;
366 case 128000:
367 dcb.BaudRate = CBR_128000; /* Not available on Unix? */
368 break;
369 case 256000:
370 dcb.BaudRate = CBR_256000; /* Not available on Unix? */
371 break;
372 default:
373 sr_err("Unsupported baudrate: %d.", baudrate);
374 return SR_ERR;
375 }
376 sr_spew("Configuring baudrate to %d (%d).", baudrate, dcb.BaudRate);
377
378 sr_spew("Configuring %d data bits.", bits);
379 dcb.ByteSize = bits;
380
381 sr_spew("Configuring %d stop bits.", stopbits);
382 switch (stopbits) {
383 /* Note: There's also ONE5STOPBITS == 1.5 (unneeded so far). */
384 case 1:
385 dcb.StopBits = ONESTOPBIT;
386 break;
387 case 2:
388 dcb.StopBits = TWOSTOPBITS;
389 break;
390 default:
391 sr_err("Unsupported stopbits number: %d.", stopbits);
392 return SR_ERR;
393 }
394
395 switch (parity) {
396 /* Note: There's also SPACEPARITY, MARKPARITY (unneeded so far). */
397 case SERIAL_PARITY_NONE:
398 sr_spew("Configuring no parity.");
399 dcb.Parity = NOPARITY;
400 break;
401 case SERIAL_PARITY_EVEN:
402 sr_spew("Configuring even parity.");
403 dcb.Parity = EVENPARITY;
404 break;
405 case SERIAL_PARITY_ODD:
406 sr_spew("Configuring odd parity.");
407 dcb.Parity = ODDPARITY;
408 break;
409 default:
410 sr_err("Unsupported parity setting: %d.", parity);
411 return SR_ERR;
412 }
413
414 if (rts != -1) {
415 sr_spew("Setting RTS %s.", rts ? "high" : "low");
416 if (rts)
417 dcb.fRtsControl = RTS_CONTROL_ENABLE;
418 else
419 dcb.fRtsControl = RTS_CONTROL_DISABLE;
420 }
421
422 if (dtr != -1) {
423 sr_spew("Setting DTR %s.", dtr ? "high" : "low");
424 if (dtr)
425 dcb.fDtrControl = DTR_CONTROL_ENABLE;
426 else
427 dcb.fDtrControl = DTR_CONTROL_DISABLE;
428 }
429
430 if (!SetCommState(hdl, &dcb)) {
431 sr_err("Failed to set comm state on port %s (fd %d): %d.",
432 serial->port, serial->fd, GetLastError());
433 return SR_ERR;
434 }
435#else
436 struct termios term;
437 speed_t baud;
438 int ret, controlbits;
439
440 if (tcgetattr(serial->fd, &term) < 0) {
441 sr_err("tcgetattr() error on port %s (fd %d): %s.",
442 serial->port, serial->fd, strerror(errno));
443 return SR_ERR;
444 }
445
446 switch (baudrate) {
447 case 50:
448 baud = B50;
449 break;
450 case 75:
451 baud = B75;
452 break;
453 case 110:
454 baud = B110;
455 break;
456 case 134:
457 baud = B134;
458 break;
459 case 150:
460 baud = B150;
461 break;
462 case 200:
463 baud = B200;
464 break;
465 case 300:
466 baud = B300;
467 break;
468 case 600:
469 baud = B600;
470 break;
471 case 1200:
472 baud = B1200;
473 break;
474 case 1800:
475 baud = B1800;
476 break;
477 case 2400:
478 baud = B2400;
479 break;
480 case 4800:
481 baud = B4800;
482 break;
483 case 9600:
484 baud = B9600;
485 break;
486 case 19200:
487 baud = B19200;
488 break;
489 case 38400:
490 baud = B38400;
491 break;
492 case 57600:
493 baud = B57600;
494 break;
495 case 115200:
496 baud = B115200;
497 break;
498 case 230400:
499 baud = B230400;
500 break;
501#if !defined(__APPLE__) && !defined(__OpenBSD__)
502 case 460800:
503 baud = B460800;
504 break;
505#endif
506 default:
507 sr_err("Unsupported baudrate: %d.", baudrate);
508 return SR_ERR;
509 }
510
511 sr_spew("Configuring output baudrate to %d (%d).", baudrate, baud);
512 if (cfsetospeed(&term, baud) < 0) {
513 sr_err("cfsetospeed() error: %s.", strerror(errno));
514 return SR_ERR;
515 }
516
517 sr_spew("Configuring input baudrate to %d (%d).", baudrate, baud);
518 if (cfsetispeed(&term, baud) < 0) {
519 sr_err("cfsetispeed() error: %s.", strerror(errno));
520 return SR_ERR;
521 }
522
523 sr_spew("Configuring %d data bits.", bits);
524 term.c_cflag &= ~CSIZE;
525 switch (bits) {
526 case 8:
527 term.c_cflag |= CS8;
528 break;
529 case 7:
530 term.c_cflag |= CS7;
531 break;
532 default:
533 sr_err("Unsupported data bits number %d.", bits);
534 return SR_ERR;
535 }
536
537 sr_spew("Configuring %d stop bits.", stopbits);
538 term.c_cflag &= ~CSTOPB;
539 switch (stopbits) {
540 case 1:
541 term.c_cflag &= ~CSTOPB;
542 break;
543 case 2:
544 term.c_cflag |= CSTOPB;
545 break;
546 default:
547 sr_err("Unsupported stopbits number %d.", stopbits);
548 return SR_ERR;
549 }
550
551 term.c_iflag &= ~(IXON | IXOFF);
552 term.c_cflag &= ~CRTSCTS;
553 switch (flowcontrol) {
554 case 0:
555 /* No flow control. */
556 sr_spew("Configuring no flow control.");
557 break;
558 case 1:
559 sr_spew("Configuring RTS/CTS flow control.");
560 term.c_cflag |= CRTSCTS;
561 break;
562 case 2:
563 sr_spew("Configuring XON/XOFF flow control.");
564 term.c_iflag |= IXON | IXOFF;
565 break;
566 default:
567 sr_err("Unsupported flow control setting %d.", flowcontrol);
568 return SR_ERR;
569 }
570
571 term.c_iflag &= ~IGNPAR;
572 term.c_cflag &= ~(PARENB | PARODD);
573 switch (parity) {
574 case SERIAL_PARITY_NONE:
575 sr_spew("Configuring no parity.");
576 term.c_iflag |= IGNPAR;
577 break;
578 case SERIAL_PARITY_EVEN:
579 sr_spew("Configuring even parity.");
580 term.c_cflag |= PARENB;
581 break;
582 case SERIAL_PARITY_ODD:
583 sr_spew("Configuring odd parity.");
584 term.c_cflag |= PARENB | PARODD;
585 break;
586 default:
587 sr_err("Unsupported parity setting %d.", parity);
588 return SR_ERR;
589 }
590
591 /* Turn off all serial port cooking. */
592 term.c_iflag &= ~(ISTRIP | INLCR | ICRNL);
593 term.c_oflag &= ~(ONLCR | OCRNL | ONOCR);
594#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
595 term.c_oflag &= ~OFILL;
596#endif
597
598 /* Disable canonical mode, and don't echo input characters. */
599 term.c_lflag &= ~(ICANON | ECHO);
600
601 /* Write the configured settings. */
602 if (tcsetattr(serial->fd, TCSADRAIN, &term) < 0) {
603 sr_err("tcsetattr() error: %s.", strerror(errno));
604 return SR_ERR;
605 }
606
607 if (rts != -1) {
608 sr_spew("Setting RTS %s.", rts ? "high" : "low");
609 controlbits = TIOCM_RTS;
610 if ((ret = ioctl(serial->fd, rts ? TIOCMBIS : TIOCMBIC,
611 &controlbits)) < 0) {
612 sr_err("Error setting RTS: %s.", strerror(errno));
613 return SR_ERR;
614 }
615 }
616
617 if (dtr != -1) {
618 sr_spew("Setting DTR %s.", dtr ? "high" : "low");
619 controlbits = TIOCM_DTR;
620 if ((ret = ioctl(serial->fd, dtr ? TIOCMBIS : TIOCMBIC,
621 &controlbits)) < 0) {
622 sr_err("Error setting DTR: %s.", strerror(errno));
623 return SR_ERR;
624 }
625 }
626
627#endif
628
629 return SR_OK;
630}
631
632/**
633 * Set serial parameters for the specified serial port.
634 *
635 * @param serial Previously initialized serial port structure.
636 * @param paramstr A serial communication parameters string, in the form
637 * of <speed>/<data bits><parity><stopbits><flow>, for example "9600/8n1" or
638 * "600/7o2" or "460800/8n1/flow=2" where flow is 0 for none, 1 for rts/cts and 2 for xon/xoff.
639 *
640 * @return SR_OK upon success, SR_ERR upon failure.
641 */
642#define SERIAL_COMM_SPEC "^(\\d+)/([78])([neo])([12])(.*)$"
643SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial,
644 const char *paramstr)
645{
646 GRegex *reg;
647 GMatchInfo *match;
648 int speed, databits, parity, stopbits, flow, rts, dtr, i;
649 char *mstr, **opts, **kv;
650
651 speed = databits = parity = stopbits = flow = 0;
652 rts = dtr = -1;
653 sr_spew("Parsing parameters from \"%s\".", paramstr);
654 reg = g_regex_new(SERIAL_COMM_SPEC, 0, 0, NULL);
655 if (g_regex_match(reg, paramstr, 0, &match)) {
656 if ((mstr = g_match_info_fetch(match, 1)))
657 speed = strtoul(mstr, NULL, 10);
658 g_free(mstr);
659 if ((mstr = g_match_info_fetch(match, 2)))
660 databits = strtoul(mstr, NULL, 10);
661 g_free(mstr);
662 if ((mstr = g_match_info_fetch(match, 3))) {
663 switch (mstr[0]) {
664 case 'n':
665 parity = SERIAL_PARITY_NONE;
666 break;
667 case 'e':
668 parity = SERIAL_PARITY_EVEN;
669 break;
670 case 'o':
671 parity = SERIAL_PARITY_ODD;
672 break;
673 }
674 }
675 g_free(mstr);
676 if ((mstr = g_match_info_fetch(match, 4)))
677 stopbits = strtoul(mstr, NULL, 10);
678 g_free(mstr);
679 if ((mstr = g_match_info_fetch(match, 5)) && mstr[0] != '\0') {
680 if (mstr[0] != '/') {
681 sr_dbg("missing separator before extra options");
682 speed = 0;
683 } else {
684 /* A set of "key=value" options separated by / */
685 opts = g_strsplit(mstr + 1, "/", 0);
686 for (i = 0; opts[i]; i++) {
687 kv = g_strsplit(opts[i], "=", 2);
688 if (!strncmp(kv[0], "rts", 3)) {
689 if (kv[1][0] == '1')
690 rts = 1;
691 else if (kv[1][0] == '0')
692 rts = 0;
693 else {
694 sr_dbg("invalid value for rts: %c", kv[1][0]);
695 speed = 0;
696 }
697 } else if (!strncmp(kv[0], "dtr", 3)) {
698 if (kv[1][0] == '1')
699 dtr = 1;
700 else if (kv[1][0] == '0')
701 dtr = 0;
702 else {
703 sr_dbg("invalid value for dtr: %c", kv[1][0]);
704 speed = 0;
705 }
706 } else if (!strncmp(kv[0], "flow", 4)) {
707 if (kv[1][0] == '0')
708 flow = 0;
709 else if (kv[1][0] == '1')
710 flow = 1;
711 else if (kv[1][0] == '2')
712 flow = 2;
713 else {
714 sr_dbg("invalid value for flow: %c", kv[1][0]);
715 speed = 0;
716 }
717 }
718 g_strfreev(kv);
719 }
720 g_strfreev(opts);
721 }
722 }
723 g_free(mstr);
724 }
725 g_match_info_unref(match);
726 g_regex_unref(reg);
727
728 if (speed) {
729 return serial_set_params(serial, speed, databits, parity,
730 stopbits, flow, rts, dtr);
731 } else {
732 sr_dbg("Could not infer speed from parameter string.");
733 return SR_ERR_ARG;
734 }
735}
736
737/**
738 * Read a line from the specified serial port.
739 *
740 * @param serial Previously initialized serial port structure.
741 * @param buf Buffer where to store the bytes that are read.
742 * @param buflen Size of the buffer.
743 * @param timeout_ms How long to wait for a line to come in.
744 *
745 * Reading stops when CR of LR is found, which is stripped from the buffer.
746 *
747 * @return SR_OK on success, SR_ERR on failure.
748 */
749SR_PRIV int serial_readline(struct sr_serial_dev_inst *serial, char **buf,
750 int *buflen, gint64 timeout_ms)
751{
752 gint64 start;
753 int maxlen, len;
754
755 if (!serial || serial->fd == -1) {
756 sr_dbg("Invalid serial port.");
757 return SR_ERR;
758 }
759
760 if (serial->fd == -1) {
761 sr_dbg("Cannot use unopened serial port %s (fd %d).",
762 serial->port, serial->fd);
763 return -1;
764 }
765
766 timeout_ms *= 1000;
767 start = g_get_monotonic_time();
768
769 maxlen = *buflen;
770 *buflen = len = 0;
771 while(1) {
772 len = maxlen - *buflen - 1;
773 if (len < 1)
774 break;
775 len = serial_read(serial, *buf + *buflen, 1);
776 if (len > 0) {
777 *buflen += len;
778 *(*buf + *buflen) = '\0';
779 if (*buflen > 0 && (*(*buf + *buflen - 1) == '\r'
780 || *(*buf + *buflen - 1) == '\n')) {
781 /* Strip CR/LF and terminate. */
782 *(*buf + --*buflen) = '\0';
783 break;
784 }
785 }
786 if (g_get_monotonic_time() - start > timeout_ms)
787 /* Timeout */
788 break;
789 if (len < 1)
790 g_usleep(2000);
791 }
792 if (*buflen)
793 sr_dbg("Received %d: '%s'.", *buflen, *buf);
794
795 return SR_OK;
796}
797
798/**
799 * Try to find a valid packet in a serial data stream.
800 *
801 * @param serial Previously initialized serial port structure.
802 * @param buf Buffer containing the bytes to write.
803 * @param count Size of the buffer.
804 * @param packet_size Size, in bytes, of a valid packet.
805 * @param is_valid Callback that assesses whether the packet is valid or not.
806 * @param timeout_ms The timeout after which, if no packet is detected, to
807 * abort scanning.
808 * @param baudrate The baudrate of the serial port. This parameter is not
809 * critical, but it helps fine tune the serial port polling
810 * delay.
811 *
812 * @return SR_OK if a valid packet is found within the given timeout,
813 * SR_ERR upon failure.
814 */
815SR_PRIV int serial_stream_detect(struct sr_serial_dev_inst *serial,
816 uint8_t *buf, size_t *buflen,
817 size_t packet_size, packet_valid_t is_valid,
818 uint64_t timeout_ms, int baudrate)
819{
820 uint64_t start, time, byte_delay_us;
821 size_t ibuf, i, maxlen;
822 int len;
823
824 maxlen = *buflen;
825
826 sr_dbg("Detecting packets on FD %d (timeout = %" PRIu64
827 "ms, baudrate = %d).", serial->fd, timeout_ms, baudrate);
828
829 if (maxlen < (packet_size / 2) ) {
830 sr_err("Buffer size must be at least twice the packet size.");
831 return SR_ERR;
832 }
833
834 /* Assume 8n1 transmission. That is 10 bits for every byte. */
835 byte_delay_us = 10 * (1000000 / baudrate);
836 start = g_get_monotonic_time();
837
838 i = ibuf = len = 0;
839 while (ibuf < maxlen) {
840 len = serial_read(serial, &buf[ibuf], 1);
841 if (len > 0) {
842 ibuf += len;
843 } else if (len == 0) {
844 /* No logging, already done in serial_read(). */
845 } else {
846 /* Error reading byte, but continuing anyway. */
847 }
848
849 time = g_get_monotonic_time() - start;
850 time /= 1000;
851
852 if ((ibuf - i) >= packet_size) {
853 /* We have at least a packet's worth of data. */
854 if (is_valid(&buf[i])) {
855 sr_spew("Found valid %d-byte packet after "
856 "%" PRIu64 "ms.", (ibuf - i), time);
857 *buflen = ibuf;
858 return SR_OK;
859 } else {
860 sr_spew("Got %d bytes, but not a valid "
861 "packet.", (ibuf - i));
862 }
863 /* Not a valid packet. Continue searching. */
864 i++;
865 }
866 if (time >= timeout_ms) {
867 /* Timeout */
868 sr_dbg("Detection timed out after %dms.", time);
869 break;
870 }
871 if (len < 1)
872 g_usleep(byte_delay_us);
873 }
874
875 *buflen = ibuf;
876
877 sr_err("Didn't find a valid packet (read %d bytes).", *buflen);
878
879 return SR_ERR;
880}
Hardware access and backend lib