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1 /*
2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
3  * Licensed under the GPL
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->driver->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->driver->read_irq, chan);
199 		if (chan->output && chan->enabled)
200 			um_free_irq(chan->line->driver->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 	}
217 	else {
218 		if (chan->input && chan->enabled)
219 			um_free_irq(chan->line->driver->read_irq, chan);
220 		if (chan->output && chan->enabled)
221 			um_free_irq(chan->line->driver->write_irq, chan);
222 		chan->enabled = 0;
223 	}
224 	if (chan->ops->close != NULL)
225 		(*chan->ops->close)(chan->fd, chan->data);
226 
227 	chan->opened = 0;
228 	chan->fd = -1;
229 }
230 
close_chan(struct line * line)231 void close_chan(struct line *line)
232 {
233 	struct chan *chan;
234 
235 	/* Close in reverse order as open in case more than one of them
236 	 * refers to the same device and they save and restore that device's
237 	 * state.  Then, the first one opened will have the original state,
238 	 * so it must be the last closed.
239 	 */
240 	list_for_each_entry_reverse(chan, &line->chan_list, list) {
241 		close_one_chan(chan, 0);
242 	}
243 }
244 
deactivate_chan(struct chan * chan,int irq)245 void deactivate_chan(struct chan *chan, int irq)
246 {
247 	if (chan && chan->enabled)
248 		deactivate_fd(chan->fd, irq);
249 }
250 
reactivate_chan(struct chan * chan,int irq)251 void reactivate_chan(struct chan *chan, int irq)
252 {
253 	if (chan && chan->enabled)
254 		reactivate_fd(chan->fd, irq);
255 }
256 
write_chan(struct chan * chan,const char * buf,int len,int write_irq)257 int write_chan(struct chan *chan, const char *buf, int len,
258 	       int write_irq)
259 {
260 	int n, ret = 0;
261 
262 	if (len == 0 || !chan || !chan->ops->write)
263 		return 0;
264 
265 	n = chan->ops->write(chan->fd, buf, len, chan->data);
266 	if (chan->primary) {
267 		ret = n;
268 		if ((ret == -EAGAIN) || ((ret >= 0) && (ret < len)))
269 			reactivate_fd(chan->fd, write_irq);
270 	}
271 	return ret;
272 }
273 
console_write_chan(struct chan * chan,const char * buf,int len)274 int console_write_chan(struct chan *chan, const char *buf, int len)
275 {
276 	int n, ret = 0;
277 
278 	if (!chan || !chan->ops->console_write)
279 		return 0;
280 
281 	n = chan->ops->console_write(chan->fd, buf, len);
282 	if (chan->primary)
283 		ret = n;
284 	return ret;
285 }
286 
console_open_chan(struct line * line,struct console * co)287 int console_open_chan(struct line *line, struct console *co)
288 {
289 	int err;
290 
291 	err = open_chan(&line->chan_list);
292 	if (err)
293 		return err;
294 
295 	printk(KERN_INFO "Console initialized on /dev/%s%d\n", co->name,
296 	       co->index);
297 	return 0;
298 }
299 
chan_window_size(struct line * line,unsigned short * rows_out,unsigned short * cols_out)300 int chan_window_size(struct line *line, unsigned short *rows_out,
301 		      unsigned short *cols_out)
302 {
303 	struct chan *chan;
304 
305 	chan = line->chan_in;
306 	if (chan && chan->primary) {
307 		if (chan->ops->window_size == NULL)
308 			return 0;
309 		return chan->ops->window_size(chan->fd, chan->data,
310 					      rows_out, cols_out);
311 	}
312 	chan = line->chan_out;
313 	if (chan && chan->primary) {
314 		if (chan->ops->window_size == NULL)
315 			return 0;
316 		return chan->ops->window_size(chan->fd, chan->data,
317 					      rows_out, cols_out);
318 	}
319 	return 0;
320 }
321 
free_one_chan(struct chan * chan)322 static void free_one_chan(struct chan *chan)
323 {
324 	list_del(&chan->list);
325 
326 	close_one_chan(chan, 0);
327 
328 	if (chan->ops->free != NULL)
329 		(*chan->ops->free)(chan->data);
330 
331 	if (chan->primary && chan->output)
332 		ignore_sigio_fd(chan->fd);
333 	kfree(chan);
334 }
335 
free_chan(struct list_head * chans)336 static void free_chan(struct list_head *chans)
337 {
338 	struct list_head *ele, *next;
339 	struct chan *chan;
340 
341 	list_for_each_safe(ele, next, chans) {
342 		chan = list_entry(ele, struct chan, list);
343 		free_one_chan(chan);
344 	}
345 }
346 
one_chan_config_string(struct chan * chan,char * str,int size,char ** error_out)347 static int one_chan_config_string(struct chan *chan, char *str, int size,
348 				  char **error_out)
349 {
350 	int n = 0;
351 
352 	if (chan == NULL) {
353 		CONFIG_CHUNK(str, size, n, "none", 1);
354 		return n;
355 	}
356 
357 	CONFIG_CHUNK(str, size, n, chan->ops->type, 0);
358 
359 	if (chan->dev == NULL) {
360 		CONFIG_CHUNK(str, size, n, "", 1);
361 		return n;
362 	}
363 
364 	CONFIG_CHUNK(str, size, n, ":", 0);
365 	CONFIG_CHUNK(str, size, n, chan->dev, 0);
366 
367 	return n;
368 }
369 
chan_pair_config_string(struct chan * in,struct chan * out,char * str,int size,char ** error_out)370 static int chan_pair_config_string(struct chan *in, struct chan *out,
371 				   char *str, int size, char **error_out)
372 {
373 	int n;
374 
375 	n = one_chan_config_string(in, str, size, error_out);
376 	str += n;
377 	size -= n;
378 
379 	if (in == out) {
380 		CONFIG_CHUNK(str, size, n, "", 1);
381 		return n;
382 	}
383 
384 	CONFIG_CHUNK(str, size, n, ",", 1);
385 	n = one_chan_config_string(out, str, size, error_out);
386 	str += n;
387 	size -= n;
388 	CONFIG_CHUNK(str, size, n, "", 1);
389 
390 	return n;
391 }
392 
chan_config_string(struct line * line,char * str,int size,char ** error_out)393 int chan_config_string(struct line *line, char *str, int size,
394 		       char **error_out)
395 {
396 	struct chan *in = line->chan_in, *out = line->chan_out;
397 
398 	if (in && !in->primary)
399 		in = NULL;
400 	if (out && !out->primary)
401 		out = NULL;
402 
403 	return chan_pair_config_string(in, out, str, size, error_out);
404 }
405 
406 struct chan_type {
407 	char *key;
408 	const struct chan_ops *ops;
409 };
410 
411 static const struct chan_type chan_table[] = {
412 	{ "fd", &fd_ops },
413 
414 #ifdef CONFIG_NULL_CHAN
415 	{ "null", &null_ops },
416 #else
417 	{ "null", &not_configged_ops },
418 #endif
419 
420 #ifdef CONFIG_PORT_CHAN
421 	{ "port", &port_ops },
422 #else
423 	{ "port", &not_configged_ops },
424 #endif
425 
426 #ifdef CONFIG_PTY_CHAN
427 	{ "pty", &pty_ops },
428 	{ "pts", &pts_ops },
429 #else
430 	{ "pty", &not_configged_ops },
431 	{ "pts", &not_configged_ops },
432 #endif
433 
434 #ifdef CONFIG_TTY_CHAN
435 	{ "tty", &tty_ops },
436 #else
437 	{ "tty", &not_configged_ops },
438 #endif
439 
440 #ifdef CONFIG_XTERM_CHAN
441 	{ "xterm", &xterm_ops },
442 #else
443 	{ "xterm", &not_configged_ops },
444 #endif
445 };
446 
parse_chan(struct line * line,char * str,int device,const struct chan_opts * opts,char ** error_out)447 static struct chan *parse_chan(struct line *line, char *str, int device,
448 			       const struct chan_opts *opts, char **error_out)
449 {
450 	const struct chan_type *entry;
451 	const struct chan_ops *ops;
452 	struct chan *chan;
453 	void *data;
454 	int i;
455 
456 	ops = NULL;
457 	data = NULL;
458 	for(i = 0; i < ARRAY_SIZE(chan_table); i++) {
459 		entry = &chan_table[i];
460 		if (!strncmp(str, entry->key, strlen(entry->key))) {
461 			ops = entry->ops;
462 			str += strlen(entry->key);
463 			break;
464 		}
465 	}
466 	if (ops == NULL) {
467 		*error_out = "No match for configured backends";
468 		return NULL;
469 	}
470 
471 	data = (*ops->init)(str, device, opts);
472 	if (data == NULL) {
473 		*error_out = "Configuration failed";
474 		return NULL;
475 	}
476 
477 	chan = kmalloc(sizeof(*chan), GFP_ATOMIC);
478 	if (chan == NULL) {
479 		*error_out = "Memory allocation failed";
480 		return NULL;
481 	}
482 	*chan = ((struct chan) { .list	 	= LIST_HEAD_INIT(chan->list),
483 				 .free_list 	=
484 				 	LIST_HEAD_INIT(chan->free_list),
485 				 .line		= line,
486 				 .primary	= 1,
487 				 .input		= 0,
488 				 .output 	= 0,
489 				 .opened  	= 0,
490 				 .enabled  	= 0,
491 				 .fd 		= -1,
492 				 .ops 		= ops,
493 				 .data 		= data });
494 	return chan;
495 }
496 
parse_chan_pair(char * str,struct line * line,int device,const struct chan_opts * opts,char ** error_out)497 int parse_chan_pair(char *str, struct line *line, int device,
498 		    const struct chan_opts *opts, char **error_out)
499 {
500 	struct list_head *chans = &line->chan_list;
501 	struct chan *new;
502 	char *in, *out;
503 
504 	if (!list_empty(chans)) {
505 		line->chan_in = line->chan_out = NULL;
506 		free_chan(chans);
507 		INIT_LIST_HEAD(chans);
508 	}
509 
510 	if (!str)
511 		return 0;
512 
513 	out = strchr(str, ',');
514 	if (out != NULL) {
515 		in = str;
516 		*out = '\0';
517 		out++;
518 		new = parse_chan(line, in, device, opts, error_out);
519 		if (new == NULL)
520 			return -1;
521 
522 		new->input = 1;
523 		list_add(&new->list, chans);
524 		line->chan_in = new;
525 
526 		new = parse_chan(line, out, device, opts, error_out);
527 		if (new == NULL)
528 			return -1;
529 
530 		list_add(&new->list, chans);
531 		new->output = 1;
532 		line->chan_out = new;
533 	}
534 	else {
535 		new = parse_chan(line, str, device, opts, error_out);
536 		if (new == NULL)
537 			return -1;
538 
539 		list_add(&new->list, chans);
540 		new->input = 1;
541 		new->output = 1;
542 		line->chan_in = line->chan_out = new;
543 	}
544 	return 0;
545 }
546 
chan_interrupt(struct line * line,int irq)547 void chan_interrupt(struct line *line, int irq)
548 {
549 	struct tty_port *port = &line->port;
550 	struct chan *chan = line->chan_in;
551 	int err;
552 	char c;
553 
554 	if (!chan || !chan->ops->read)
555 		goto out;
556 
557 	do {
558 		if (!tty_buffer_request_room(port, 1)) {
559 			schedule_delayed_work(&line->task, 1);
560 			goto out;
561 		}
562 		err = chan->ops->read(chan->fd, &c, chan->data);
563 		if (err > 0)
564 			tty_insert_flip_char(port, c, TTY_NORMAL);
565 	} while (err > 0);
566 
567 	if (err == 0)
568 		reactivate_fd(chan->fd, irq);
569 	if (err == -EIO) {
570 		if (chan->primary) {
571 			tty_port_tty_hangup(&line->port, false);
572 			if (line->chan_out != chan)
573 				close_one_chan(line->chan_out, 1);
574 		}
575 		close_one_chan(chan, 1);
576 		if (chan->primary)
577 			return;
578 	}
579  out:
580 	tty_flip_buffer_push(port);
581 }
582