1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
4  */
5 
6 #include <linux/slab.h>
7 #include <linux/tty.h>
8 #include <linux/tty_flip.h>
9 #include "chan.h"
10 #include <os.h>
11 #include <irq_kern.h>
12 
13 #ifdef CONFIG_NOCONFIG_CHAN
not_configged_init(char * str,int device,const struct chan_opts * opts)14 static void *not_configged_init(char *str, int device,
15 				const struct chan_opts *opts)
16 {
17 	printk(KERN_ERR "Using a channel type which is configured out of "
18 	       "UML\n");
19 	return NULL;
20 }
21 
not_configged_open(int input,int output,int primary,void * data,char ** dev_out)22 static int not_configged_open(int input, int output, int primary, void *data,
23 			      char **dev_out)
24 {
25 	printk(KERN_ERR "Using a channel type which is configured out of "
26 	       "UML\n");
27 	return -ENODEV;
28 }
29 
not_configged_close(int fd,void * data)30 static void not_configged_close(int fd, void *data)
31 {
32 	printk(KERN_ERR "Using a channel type which is configured out of "
33 	       "UML\n");
34 }
35 
not_configged_read(int fd,char * c_out,void * data)36 static int not_configged_read(int fd, char *c_out, void *data)
37 {
38 	printk(KERN_ERR "Using a channel type which is configured out of "
39 	       "UML\n");
40 	return -EIO;
41 }
42 
not_configged_write(int fd,const char * buf,int len,void * data)43 static int not_configged_write(int fd, const char *buf, int len, void *data)
44 {
45 	printk(KERN_ERR "Using a channel type which is configured out of "
46 	       "UML\n");
47 	return -EIO;
48 }
49 
not_configged_console_write(int fd,const char * buf,int len)50 static int not_configged_console_write(int fd, const char *buf, int len)
51 {
52 	printk(KERN_ERR "Using a channel type which is configured out of "
53 	       "UML\n");
54 	return -EIO;
55 }
56 
not_configged_window_size(int fd,void * data,unsigned short * rows,unsigned short * cols)57 static int not_configged_window_size(int fd, void *data, unsigned short *rows,
58 				     unsigned short *cols)
59 {
60 	printk(KERN_ERR "Using a channel type which is configured out of "
61 	       "UML\n");
62 	return -ENODEV;
63 }
64 
not_configged_free(void * data)65 static void not_configged_free(void *data)
66 {
67 	printk(KERN_ERR "Using a channel type which is configured out of "
68 	       "UML\n");
69 }
70 
71 static const struct chan_ops not_configged_ops = {
72 	.init		= not_configged_init,
73 	.open		= not_configged_open,
74 	.close		= not_configged_close,
75 	.read		= not_configged_read,
76 	.write		= not_configged_write,
77 	.console_write	= not_configged_console_write,
78 	.window_size	= not_configged_window_size,
79 	.free		= not_configged_free,
80 	.winch		= 0,
81 };
82 #endif /* CONFIG_NOCONFIG_CHAN */
83 
open_one_chan(struct chan * chan)84 static int open_one_chan(struct chan *chan)
85 {
86 	int fd, err;
87 
88 	if (chan->opened)
89 		return 0;
90 
91 	if (chan->ops->open == NULL)
92 		fd = 0;
93 	else fd = (*chan->ops->open)(chan->input, chan->output, chan->primary,
94 				     chan->data, &chan->dev);
95 	if (fd < 0)
96 		return fd;
97 
98 	err = os_set_fd_block(fd, 0);
99 	if (err) {
100 		(*chan->ops->close)(fd, chan->data);
101 		return err;
102 	}
103 
104 	chan->fd = fd;
105 
106 	chan->opened = 1;
107 	return 0;
108 }
109 
open_chan(struct list_head * chans)110 static int open_chan(struct list_head *chans)
111 {
112 	struct list_head *ele;
113 	struct chan *chan;
114 	int ret, err = 0;
115 
116 	list_for_each(ele, chans) {
117 		chan = list_entry(ele, struct chan, list);
118 		ret = open_one_chan(chan);
119 		if (chan->primary)
120 			err = ret;
121 	}
122 	return err;
123 }
124 
chan_enable_winch(struct chan * chan,struct tty_port * port)125 void chan_enable_winch(struct chan *chan, struct tty_port *port)
126 {
127 	if (chan && chan->primary && chan->ops->winch)
128 		register_winch(chan->fd, port);
129 }
130 
line_timer_cb(struct work_struct * work)131 static void line_timer_cb(struct work_struct *work)
132 {
133 	struct line *line = container_of(work, struct line, task.work);
134 
135 	if (!line->throttled)
136 		chan_interrupt(line, line->read_irq);
137 }
138 
enable_chan(struct line * line)139 int enable_chan(struct line *line)
140 {
141 	struct list_head *ele;
142 	struct chan *chan;
143 	int err;
144 
145 	INIT_DELAYED_WORK(&line->task, line_timer_cb);
146 
147 	list_for_each(ele, &line->chan_list) {
148 		chan = list_entry(ele, struct chan, list);
149 		err = open_one_chan(chan);
150 		if (err) {
151 			if (chan->primary)
152 				goto out_close;
153 
154 			continue;
155 		}
156 
157 		if (chan->enabled)
158 			continue;
159 		err = line_setup_irq(chan->fd, chan->input, chan->output, line,
160 				     chan);
161 		if (err)
162 			goto out_close;
163 
164 		chan->enabled = 1;
165 	}
166 
167 	return 0;
168 
169  out_close:
170 	close_chan(line);
171 	return err;
172 }
173 
174 /* Items are added in IRQ context, when free_irq can't be called, and
175  * removed in process context, when it can.
176  * This handles interrupt sources which disappear, and which need to
177  * be permanently disabled.  This is discovered in IRQ context, but
178  * the freeing of the IRQ must be done later.
179  */
180 static DEFINE_SPINLOCK(irqs_to_free_lock);
181 static LIST_HEAD(irqs_to_free);
182 
free_irqs(void)183 void free_irqs(void)
184 {
185 	struct chan *chan;
186 	LIST_HEAD(list);
187 	struct list_head *ele;
188 	unsigned long flags;
189 
190 	spin_lock_irqsave(&irqs_to_free_lock, flags);
191 	list_splice_init(&irqs_to_free, &list);
192 	spin_unlock_irqrestore(&irqs_to_free_lock, flags);
193 
194 	list_for_each(ele, &list) {
195 		chan = list_entry(ele, struct chan, free_list);
196 
197 		if (chan->input && chan->enabled)
198 			um_free_irq(chan->line->read_irq, chan);
199 		if (chan->output && chan->enabled)
200 			um_free_irq(chan->line->write_irq, chan);
201 		chan->enabled = 0;
202 	}
203 }
204 
close_one_chan(struct chan * chan,int delay_free_irq)205 static void close_one_chan(struct chan *chan, int delay_free_irq)
206 {
207 	unsigned long flags;
208 
209 	if (!chan->opened)
210 		return;
211 
212 	if (delay_free_irq) {
213 		spin_lock_irqsave(&irqs_to_free_lock, flags);
214 		list_add(&chan->free_list, &irqs_to_free);
215 		spin_unlock_irqrestore(&irqs_to_free_lock, flags);
216 	} else {
217 		if (chan->input && chan->enabled)
218 			um_free_irq(chan->line->read_irq, chan);
219 		if (chan->output && chan->enabled)
220 			um_free_irq(chan->line->write_irq, chan);
221 		chan->enabled = 0;
222 	}
223 	if (chan->ops->close != NULL)
224 		(*chan->ops->close)(chan->fd, chan->data);
225 
226 	chan->opened = 0;
227 	chan->fd = -1;
228 }
229 
close_chan(struct line * line)230 void close_chan(struct line *line)
231 {
232 	struct chan *chan;
233 
234 	/* Close in reverse order as open in case more than one of them
235 	 * refers to the same device and they save and restore that device's
236 	 * state.  Then, the first one opened will have the original state,
237 	 * so it must be the last closed.
238 	 */
239 	list_for_each_entry_reverse(chan, &line->chan_list, list) {
240 		close_one_chan(chan, 0);
241 	}
242 }
243 
deactivate_chan(struct chan * chan,int irq)244 void deactivate_chan(struct chan *chan, int irq)
245 {
246 	if (chan && chan->enabled)
247 		deactivate_fd(chan->fd, irq);
248 }
249 
write_chan(struct chan * chan,const char * buf,int len,int write_irq)250 int write_chan(struct chan *chan, const char *buf, int len,
251 	       int write_irq)
252 {
253 	int n, ret = 0;
254 
255 	if (len == 0 || !chan || !chan->ops->write)
256 		return 0;
257 
258 	n = chan->ops->write(chan->fd, buf, len, chan->data);
259 	if (chan->primary) {
260 		ret = n;
261 	}
262 	return ret;
263 }
264 
console_write_chan(struct chan * chan,const char * buf,int len)265 int console_write_chan(struct chan *chan, const char *buf, int len)
266 {
267 	int n, ret = 0;
268 
269 	if (!chan || !chan->ops->console_write)
270 		return 0;
271 
272 	n = chan->ops->console_write(chan->fd, buf, len);
273 	if (chan->primary)
274 		ret = n;
275 	return ret;
276 }
277 
console_open_chan(struct line * line,struct console * co)278 int console_open_chan(struct line *line, struct console *co)
279 {
280 	int err;
281 
282 	err = open_chan(&line->chan_list);
283 	if (err)
284 		return err;
285 
286 	printk(KERN_INFO "Console initialized on /dev/%s%d\n", co->name,
287 	       co->index);
288 	return 0;
289 }
290 
chan_window_size(struct line * line,unsigned short * rows_out,unsigned short * cols_out)291 int chan_window_size(struct line *line, unsigned short *rows_out,
292 		      unsigned short *cols_out)
293 {
294 	struct chan *chan;
295 
296 	chan = line->chan_in;
297 	if (chan && chan->primary) {
298 		if (chan->ops->window_size == NULL)
299 			return 0;
300 		return chan->ops->window_size(chan->fd, chan->data,
301 					      rows_out, cols_out);
302 	}
303 	chan = line->chan_out;
304 	if (chan && chan->primary) {
305 		if (chan->ops->window_size == NULL)
306 			return 0;
307 		return chan->ops->window_size(chan->fd, chan->data,
308 					      rows_out, cols_out);
309 	}
310 	return 0;
311 }
312 
free_one_chan(struct chan * chan)313 static void free_one_chan(struct chan *chan)
314 {
315 	list_del(&chan->list);
316 
317 	close_one_chan(chan, 0);
318 
319 	if (chan->ops->free != NULL)
320 		(*chan->ops->free)(chan->data);
321 
322 	if (chan->primary && chan->output)
323 		ignore_sigio_fd(chan->fd);
324 	kfree(chan);
325 }
326 
free_chan(struct list_head * chans)327 static void free_chan(struct list_head *chans)
328 {
329 	struct list_head *ele, *next;
330 	struct chan *chan;
331 
332 	list_for_each_safe(ele, next, chans) {
333 		chan = list_entry(ele, struct chan, list);
334 		free_one_chan(chan);
335 	}
336 }
337 
one_chan_config_string(struct chan * chan,char * str,int size,char ** error_out)338 static int one_chan_config_string(struct chan *chan, char *str, int size,
339 				  char **error_out)
340 {
341 	int n = 0;
342 
343 	if (chan == NULL) {
344 		CONFIG_CHUNK(str, size, n, "none", 1);
345 		return n;
346 	}
347 
348 	CONFIG_CHUNK(str, size, n, chan->ops->type, 0);
349 
350 	if (chan->dev == NULL) {
351 		CONFIG_CHUNK(str, size, n, "", 1);
352 		return n;
353 	}
354 
355 	CONFIG_CHUNK(str, size, n, ":", 0);
356 	CONFIG_CHUNK(str, size, n, chan->dev, 0);
357 
358 	return n;
359 }
360 
chan_pair_config_string(struct chan * in,struct chan * out,char * str,int size,char ** error_out)361 static int chan_pair_config_string(struct chan *in, struct chan *out,
362 				   char *str, int size, char **error_out)
363 {
364 	int n;
365 
366 	n = one_chan_config_string(in, str, size, error_out);
367 	str += n;
368 	size -= n;
369 
370 	if (in == out) {
371 		CONFIG_CHUNK(str, size, n, "", 1);
372 		return n;
373 	}
374 
375 	CONFIG_CHUNK(str, size, n, ",", 1);
376 	n = one_chan_config_string(out, str, size, error_out);
377 	str += n;
378 	size -= n;
379 	CONFIG_CHUNK(str, size, n, "", 1);
380 
381 	return n;
382 }
383 
chan_config_string(struct line * line,char * str,int size,char ** error_out)384 int chan_config_string(struct line *line, char *str, int size,
385 		       char **error_out)
386 {
387 	struct chan *in = line->chan_in, *out = line->chan_out;
388 
389 	if (in && !in->primary)
390 		in = NULL;
391 	if (out && !out->primary)
392 		out = NULL;
393 
394 	return chan_pair_config_string(in, out, str, size, error_out);
395 }
396 
397 struct chan_type {
398 	char *key;
399 	const struct chan_ops *ops;
400 };
401 
402 static const struct chan_type chan_table[] = {
403 	{ "fd", &fd_ops },
404 
405 #ifdef CONFIG_NULL_CHAN
406 	{ "null", &null_ops },
407 #else
408 	{ "null", &not_configged_ops },
409 #endif
410 
411 #ifdef CONFIG_PORT_CHAN
412 	{ "port", &port_ops },
413 #else
414 	{ "port", &not_configged_ops },
415 #endif
416 
417 #ifdef CONFIG_PTY_CHAN
418 	{ "pty", &pty_ops },
419 	{ "pts", &pts_ops },
420 #else
421 	{ "pty", &not_configged_ops },
422 	{ "pts", &not_configged_ops },
423 #endif
424 
425 #ifdef CONFIG_TTY_CHAN
426 	{ "tty", &tty_ops },
427 #else
428 	{ "tty", &not_configged_ops },
429 #endif
430 
431 #ifdef CONFIG_XTERM_CHAN
432 	{ "xterm", &xterm_ops },
433 #else
434 	{ "xterm", &not_configged_ops },
435 #endif
436 };
437 
parse_chan(struct line * line,char * str,int device,const struct chan_opts * opts,char ** error_out)438 static struct chan *parse_chan(struct line *line, char *str, int device,
439 			       const struct chan_opts *opts, char **error_out)
440 {
441 	const struct chan_type *entry;
442 	const struct chan_ops *ops;
443 	struct chan *chan;
444 	void *data;
445 	int i;
446 
447 	ops = NULL;
448 	data = NULL;
449 	for(i = 0; i < ARRAY_SIZE(chan_table); i++) {
450 		entry = &chan_table[i];
451 		if (!strncmp(str, entry->key, strlen(entry->key))) {
452 			ops = entry->ops;
453 			str += strlen(entry->key);
454 			break;
455 		}
456 	}
457 	if (ops == NULL) {
458 		*error_out = "No match for configured backends";
459 		return NULL;
460 	}
461 
462 	data = (*ops->init)(str, device, opts);
463 	if (data == NULL) {
464 		*error_out = "Configuration failed";
465 		return NULL;
466 	}
467 
468 	chan = kmalloc(sizeof(*chan), GFP_ATOMIC);
469 	if (chan == NULL) {
470 		*error_out = "Memory allocation failed";
471 		return NULL;
472 	}
473 	*chan = ((struct chan) { .list	 	= LIST_HEAD_INIT(chan->list),
474 				 .free_list 	=
475 				 	LIST_HEAD_INIT(chan->free_list),
476 				 .line		= line,
477 				 .primary	= 1,
478 				 .input		= 0,
479 				 .output 	= 0,
480 				 .opened  	= 0,
481 				 .enabled  	= 0,
482 				 .fd 		= -1,
483 				 .ops 		= ops,
484 				 .data 		= data });
485 	return chan;
486 }
487 
parse_chan_pair(char * str,struct line * line,int device,const struct chan_opts * opts,char ** error_out)488 int parse_chan_pair(char *str, struct line *line, int device,
489 		    const struct chan_opts *opts, char **error_out)
490 {
491 	struct list_head *chans = &line->chan_list;
492 	struct chan *new;
493 	char *in, *out;
494 
495 	if (!list_empty(chans)) {
496 		line->chan_in = line->chan_out = NULL;
497 		free_chan(chans);
498 		INIT_LIST_HEAD(chans);
499 	}
500 
501 	if (!str)
502 		return 0;
503 
504 	out = strchr(str, ',');
505 	if (out != NULL) {
506 		in = str;
507 		*out = '\0';
508 		out++;
509 		new = parse_chan(line, in, device, opts, error_out);
510 		if (new == NULL)
511 			return -1;
512 
513 		new->input = 1;
514 		list_add(&new->list, chans);
515 		line->chan_in = new;
516 
517 		new = parse_chan(line, out, device, opts, error_out);
518 		if (new == NULL)
519 			return -1;
520 
521 		list_add(&new->list, chans);
522 		new->output = 1;
523 		line->chan_out = new;
524 	}
525 	else {
526 		new = parse_chan(line, str, device, opts, error_out);
527 		if (new == NULL)
528 			return -1;
529 
530 		list_add(&new->list, chans);
531 		new->input = 1;
532 		new->output = 1;
533 		line->chan_in = line->chan_out = new;
534 	}
535 	return 0;
536 }
537 
chan_interrupt(struct line * line,int irq)538 void chan_interrupt(struct line *line, int irq)
539 {
540 	struct tty_port *port = &line->port;
541 	struct chan *chan = line->chan_in;
542 	int err;
543 	char c;
544 
545 	if (!chan || !chan->ops->read)
546 		goto out;
547 
548 	do {
549 		if (!tty_buffer_request_room(port, 1)) {
550 			schedule_delayed_work(&line->task, 1);
551 			goto out;
552 		}
553 		err = chan->ops->read(chan->fd, &c, chan->data);
554 		if (err > 0)
555 			tty_insert_flip_char(port, c, TTY_NORMAL);
556 	} while (err > 0);
557 
558 	if (err == -EIO) {
559 		if (chan->primary) {
560 			tty_port_tty_hangup(&line->port, false);
561 			if (line->chan_out != chan)
562 				close_one_chan(line->chan_out, 1);
563 		}
564 		close_one_chan(chan, 1);
565 		if (chan->primary)
566 			return;
567 	}
568  out:
569 	tty_flip_buffer_push(port);
570 }
571