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
14static 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
22static 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
30static 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
36static int not_configged_read(int fd, u8 *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
43static int not_configged_write(int fd, const u8 *buf, size_t 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
50static 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
57static 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
65static 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
71static 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
84static inline bool need_output_blocking(void)
85{
86 return time_travel_mode == TT_MODE_INFCPU ||
87 time_travel_mode == TT_MODE_EXTERNAL;
88}
89
90static int open_one_chan(struct chan *chan)
91{
92 int fd, err;
93
94 if (chan->opened)
95 return 0;
96
97 if (chan->ops->open == NULL)
98 fd = 0;
99 else fd = (*chan->ops->open)(chan->input, chan->output, chan->primary,
100 chan->data, &chan->dev);
101 if (fd < 0)
102 return fd;
103
104 err = os_set_fd_block(fd, 0);
105 if (err)
106 goto out_close;
107
108 chan->fd_in = fd;
109 chan->fd_out = fd;
110
111 /*
112 * In time-travel modes infinite-CPU and external we need to guarantee
113 * that any writes to the output succeed immdiately from the point of
114 * the VM. The best way to do this is to put the FD in blocking mode
115 * and simply wait/retry until everything is written.
116 * As every write is guaranteed to complete, we also do not need to
117 * request an IRQ for the output.
118 *
119 * Note that input cannot happen in a time synchronized way. We permit
120 * it, but time passes very quickly if anything waits for a read.
121 */
122 if (chan->output && need_output_blocking()) {
123 err = os_dup_file(chan->fd_out);
124 if (err < 0)
125 goto out_close;
126
127 chan->fd_out = err;
128
129 err = os_set_fd_block(chan->fd_out, 1);
130 if (err) {
131 os_close_file(chan->fd_out);
132 goto out_close;
133 }
134 }
135
136 chan->opened = 1;
137 return 0;
138
139out_close:
140 (*chan->ops->close)(fd, chan->data);
141 return err;
142}
143
144static int open_chan(struct list_head *chans)
145{
146 struct list_head *ele;
147 struct chan *chan;
148 int ret, err = 0;
149
150 list_for_each(ele, chans) {
151 chan = list_entry(ele, struct chan, list);
152 ret = open_one_chan(chan);
153 if (chan->primary)
154 err = ret;
155 }
156 return err;
157}
158
159void chan_enable_winch(struct chan *chan, struct tty_port *port)
160{
161 if (chan && chan->primary && chan->ops->winch)
162 register_winch(fd: chan->fd_in, port);
163}
164
165static void line_timer_cb(struct work_struct *work)
166{
167 struct line *line = container_of(work, struct line, task.work);
168
169 if (!line->throttled)
170 chan_interrupt(line, irq: line->read_irq);
171}
172
173int enable_chan(struct line *line)
174{
175 struct list_head *ele;
176 struct chan *chan;
177 int err;
178
179 INIT_DELAYED_WORK(&line->task, line_timer_cb);
180
181 list_for_each(ele, &line->chan_list) {
182 chan = list_entry(ele, struct chan, list);
183 err = open_one_chan(chan);
184 if (err) {
185 if (chan->primary)
186 goto out_close;
187
188 continue;
189 }
190
191 if (chan->enabled)
192 continue;
193 err = line_setup_irq(fd: chan->fd_in, input: chan->input,
194 output: chan->output && !need_output_blocking(),
195 line, data: chan);
196 if (err)
197 goto out_close;
198
199 chan->enabled = 1;
200 }
201
202 return 0;
203
204 out_close:
205 close_chan(line);
206 return err;
207}
208
209/* Items are added in IRQ context, when free_irq can't be called, and
210 * removed in process context, when it can.
211 * This handles interrupt sources which disappear, and which need to
212 * be permanently disabled. This is discovered in IRQ context, but
213 * the freeing of the IRQ must be done later.
214 */
215static DEFINE_RAW_SPINLOCK(irqs_to_free_lock);
216static LIST_HEAD(irqs_to_free);
217
218void free_irqs(void)
219{
220 struct chan *chan;
221 LIST_HEAD(list);
222 struct list_head *ele;
223 unsigned long flags;
224
225 raw_spin_lock_irqsave(&irqs_to_free_lock, flags);
226 list_splice_init(list: &irqs_to_free, head: &list);
227 raw_spin_unlock_irqrestore(&irqs_to_free_lock, flags);
228
229 list_for_each(ele, &list) {
230 chan = list_entry(ele, struct chan, free_list);
231
232 if (chan->input && chan->enabled)
233 um_free_irq(chan->line->read_irq, chan);
234 if (chan->output && chan->enabled &&
235 !need_output_blocking())
236 um_free_irq(chan->line->write_irq, chan);
237 chan->enabled = 0;
238 }
239}
240
241static void close_one_chan(struct chan *chan, int delay_free_irq)
242{
243 unsigned long flags;
244
245 if (!chan->opened)
246 return;
247
248 if (delay_free_irq) {
249 raw_spin_lock_irqsave(&irqs_to_free_lock, flags);
250 list_add(new: &chan->free_list, head: &irqs_to_free);
251 raw_spin_unlock_irqrestore(&irqs_to_free_lock, flags);
252 } else {
253 if (chan->input && chan->enabled)
254 um_free_irq(chan->line->read_irq, chan);
255 if (chan->output && chan->enabled &&
256 !need_output_blocking())
257 um_free_irq(chan->line->write_irq, chan);
258 chan->enabled = 0;
259 }
260 if (chan->fd_out != chan->fd_in)
261 os_close_file(chan->fd_out);
262 if (chan->ops->close != NULL)
263 (*chan->ops->close)(chan->fd_in, chan->data);
264
265 chan->opened = 0;
266 chan->fd_in = -1;
267 chan->fd_out = -1;
268}
269
270void close_chan(struct line *line)
271{
272 struct chan *chan;
273
274 /* Close in reverse order as open in case more than one of them
275 * refers to the same device and they save and restore that device's
276 * state. Then, the first one opened will have the original state,
277 * so it must be the last closed.
278 */
279 list_for_each_entry_reverse(chan, &line->chan_list, list) {
280 close_one_chan(chan, delay_free_irq: 0);
281 }
282}
283
284void deactivate_chan(struct chan *chan, int irq)
285{
286 if (chan && chan->enabled)
287 deactivate_fd(chan->fd_in, irq);
288}
289
290int write_chan(struct chan *chan, const u8 *buf, size_t len, int write_irq)
291{
292 int n, ret = 0;
293
294 if (len == 0 || !chan || !chan->ops->write)
295 return 0;
296
297 n = chan->ops->write(chan->fd_out, buf, len, chan->data);
298 if (chan->primary) {
299 ret = n;
300 }
301 return ret;
302}
303
304int console_write_chan(struct chan *chan, const char *buf, int len)
305{
306 int n, ret = 0;
307
308 if (!chan || !chan->ops->console_write)
309 return 0;
310
311 n = chan->ops->console_write(chan->fd_out, buf, len);
312 if (chan->primary)
313 ret = n;
314 return ret;
315}
316
317int console_open_chan(struct line *line, struct console *co)
318{
319 int err;
320
321 err = open_chan(chans: &line->chan_list);
322 if (err)
323 return err;
324
325 printk(KERN_INFO "Console initialized on /dev/%s%d\n", co->name,
326 co->index);
327 return 0;
328}
329
330int chan_window_size(struct line *line, unsigned short *rows_out,
331 unsigned short *cols_out)
332{
333 struct chan *chan;
334
335 chan = line->chan_in;
336 if (chan && chan->primary) {
337 if (chan->ops->window_size == NULL)
338 return 0;
339 return chan->ops->window_size(chan->fd_in, chan->data,
340 rows_out, cols_out);
341 }
342 chan = line->chan_out;
343 if (chan && chan->primary) {
344 if (chan->ops->window_size == NULL)
345 return 0;
346 return chan->ops->window_size(chan->fd_in, chan->data,
347 rows_out, cols_out);
348 }
349 return 0;
350}
351
352static void free_one_chan(struct chan *chan)
353{
354 list_del(entry: &chan->list);
355
356 close_one_chan(chan, delay_free_irq: 0);
357
358 if (chan->ops->free != NULL)
359 (*chan->ops->free)(chan->data);
360
361 if (chan->primary && chan->output)
362 ignore_sigio_fd(chan->fd_in);
363 kfree(objp: chan);
364}
365
366static void free_chan(struct list_head *chans)
367{
368 struct list_head *ele, *next;
369 struct chan *chan;
370
371 list_for_each_safe(ele, next, chans) {
372 chan = list_entry(ele, struct chan, list);
373 free_one_chan(chan);
374 }
375}
376
377static int one_chan_config_string(struct chan *chan, char *str, int size,
378 char **error_out)
379{
380 int n = 0;
381
382 if (chan == NULL) {
383 CONFIG_CHUNK(str, size, n, "none", 1);
384 return n;
385 }
386
387 CONFIG_CHUNK(str, size, n, chan->ops->type, 0);
388
389 if (chan->dev == NULL) {
390 CONFIG_CHUNK(str, size, n, "", 1);
391 return n;
392 }
393
394 CONFIG_CHUNK(str, size, n, ":", 0);
395 CONFIG_CHUNK(str, size, n, chan->dev, 0);
396
397 return n;
398}
399
400static int chan_pair_config_string(struct chan *in, struct chan *out,
401 char *str, int size, char **error_out)
402{
403 int n;
404
405 n = one_chan_config_string(chan: in, str, size, error_out);
406 str += n;
407 size -= n;
408
409 if (in == out) {
410 CONFIG_CHUNK(str, size, n, "", 1);
411 return n;
412 }
413
414 CONFIG_CHUNK(str, size, n, ",", 1);
415 n = one_chan_config_string(chan: out, str, size, error_out);
416 str += n;
417 size -= n;
418 CONFIG_CHUNK(str, size, n, "", 1);
419
420 return n;
421}
422
423int chan_config_string(struct line *line, char *str, int size,
424 char **error_out)
425{
426 struct chan *in = line->chan_in, *out = line->chan_out;
427
428 if (in && !in->primary)
429 in = NULL;
430 if (out && !out->primary)
431 out = NULL;
432
433 return chan_pair_config_string(in, out, str, size, error_out);
434}
435
436struct chan_type {
437 char *key;
438 const struct chan_ops *ops;
439};
440
441static const struct chan_type chan_table[] = {
442 { "fd", &fd_ops },
443
444#ifdef CONFIG_NULL_CHAN
445 { "null", &null_ops },
446#else
447 { "null", &not_configged_ops },
448#endif
449
450#ifdef CONFIG_PORT_CHAN
451 { "port", &port_ops },
452#else
453 { "port", &not_configged_ops },
454#endif
455
456#ifdef CONFIG_PTY_CHAN
457 { "pty", &pty_ops },
458 { "pts", &pts_ops },
459#else
460 { "pty", &not_configged_ops },
461 { "pts", &not_configged_ops },
462#endif
463
464#ifdef CONFIG_TTY_CHAN
465 { "tty", &tty_ops },
466#else
467 { "tty", &not_configged_ops },
468#endif
469
470#ifdef CONFIG_XTERM_CHAN
471 { "xterm", &xterm_ops },
472#else
473 { "xterm", &not_configged_ops },
474#endif
475};
476
477static struct chan *parse_chan(struct line *line, char *str, int device,
478 const struct chan_opts *opts, char **error_out)
479{
480 const struct chan_type *entry;
481 const struct chan_ops *ops;
482 struct chan *chan;
483 void *data;
484 int i;
485
486 ops = NULL;
487 data = NULL;
488 for(i = 0; i < ARRAY_SIZE(chan_table); i++) {
489 entry = &chan_table[i];
490 if (!strncmp(str, entry->key, strlen(entry->key))) {
491 ops = entry->ops;
492 str += strlen(entry->key);
493 break;
494 }
495 }
496 if (ops == NULL) {
497 *error_out = "No match for configured backends";
498 return NULL;
499 }
500
501 data = (*ops->init)(str, device, opts);
502 if (data == NULL) {
503 *error_out = "Configuration failed";
504 return NULL;
505 }
506
507 chan = kmalloc(sizeof(*chan), GFP_ATOMIC);
508 if (chan == NULL) {
509 *error_out = "Memory allocation failed";
510 return NULL;
511 }
512 *chan = ((struct chan) { .list = LIST_HEAD_INIT(chan->list),
513 .free_list =
514 LIST_HEAD_INIT(chan->free_list),
515 .line = line,
516 .primary = 1,
517 .input = 0,
518 .output = 0,
519 .opened = 0,
520 .enabled = 0,
521 .fd_in = -1,
522 .fd_out = -1,
523 .ops = ops,
524 .data = data });
525 return chan;
526}
527
528int parse_chan_pair(char *str, struct line *line, int device,
529 const struct chan_opts *opts, char **error_out)
530{
531 struct list_head *chans = &line->chan_list;
532 struct chan *new;
533 char *in, *out;
534
535 if (!list_empty(head: chans)) {
536 line->chan_in = line->chan_out = NULL;
537 free_chan(chans);
538 INIT_LIST_HEAD(list: chans);
539 }
540
541 if (!str)
542 return 0;
543
544 out = strchr(str, ',');
545 if (out != NULL) {
546 in = str;
547 *out = '\0';
548 out++;
549 new = parse_chan(line, str: in, device, opts, error_out);
550 if (new == NULL)
551 return -1;
552
553 new->input = 1;
554 list_add(new: &new->list, head: chans);
555 line->chan_in = new;
556
557 new = parse_chan(line, str: out, device, opts, error_out);
558 if (new == NULL)
559 return -1;
560
561 list_add(new: &new->list, head: chans);
562 new->output = 1;
563 line->chan_out = new;
564 }
565 else {
566 new = parse_chan(line, str, device, opts, error_out);
567 if (new == NULL)
568 return -1;
569
570 list_add(new: &new->list, head: chans);
571 new->input = 1;
572 new->output = 1;
573 line->chan_in = line->chan_out = new;
574 }
575 return 0;
576}
577
578void chan_interrupt(struct line *line, int irq)
579{
580 struct tty_port *port = &line->port;
581 struct chan *chan = line->chan_in;
582 int err;
583 u8 c;
584
585 if (!chan || !chan->ops->read)
586 goto out;
587
588 do {
589 if (!tty_buffer_request_room(port, size: 1)) {
590 schedule_delayed_work(dwork: &line->task, delay: 1);
591 goto out;
592 }
593 err = chan->ops->read(chan->fd_in, &c, chan->data);
594 if (err > 0)
595 tty_insert_flip_char(port, ch: c, TTY_NORMAL);
596 } while (err > 0);
597
598 if (err == -EIO) {
599 if (chan->primary) {
600 tty_port_tty_hangup(port: &line->port, check_clocal: false);
601 if (line->chan_out != chan)
602 close_one_chan(chan: line->chan_out, delay_free_irq: 1);
603 }
604 close_one_chan(chan, delay_free_irq: 1);
605 if (chan->primary)
606 return;
607 }
608 out:
609 tty_flip_buffer_push(port);
610}
611

source code of linux/arch/um/drivers/chan_kern.c