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 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
110static 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
125void chan_enable_winch(struct chan *chan, struct tty_port *port)
126{
127 if (chan && chan->primary && chan->ops->winch)
128 register_winch(fd: chan->fd, port);
129}
130
131static 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, irq: line->read_irq);
137}
138
139int 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(fd: chan->fd, input: chan->input, output: chan->output, line,
160 data: 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 */
180static DEFINE_SPINLOCK(irqs_to_free_lock);
181static LIST_HEAD(irqs_to_free);
182
183void 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(list: &irqs_to_free, head: &list);
192 spin_unlock_irqrestore(lock: &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
205static 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(new: &chan->free_list, head: &irqs_to_free);
215 spin_unlock_irqrestore(lock: &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
230void 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, delay_free_irq: 0);
241 }
242}
243
244void deactivate_chan(struct chan *chan, int irq)
245{
246 if (chan && chan->enabled)
247 deactivate_fd(chan->fd, irq);
248}
249
250int write_chan(struct chan *chan, const u8 *buf, size_t len, int write_irq)
251{
252 int n, ret = 0;
253
254 if (len == 0 || !chan || !chan->ops->write)
255 return 0;
256
257 n = chan->ops->write(chan->fd, buf, len, chan->data);
258 if (chan->primary) {
259 ret = n;
260 }
261 return ret;
262}
263
264int console_write_chan(struct chan *chan, const char *buf, int len)
265{
266 int n, ret = 0;
267
268 if (!chan || !chan->ops->console_write)
269 return 0;
270
271 n = chan->ops->console_write(chan->fd, buf, len);
272 if (chan->primary)
273 ret = n;
274 return ret;
275}
276
277int console_open_chan(struct line *line, struct console *co)
278{
279 int err;
280
281 err = open_chan(chans: &line->chan_list);
282 if (err)
283 return err;
284
285 printk(KERN_INFO "Console initialized on /dev/%s%d\n", co->name,
286 co->index);
287 return 0;
288}
289
290int chan_window_size(struct line *line, unsigned short *rows_out,
291 unsigned short *cols_out)
292{
293 struct chan *chan;
294
295 chan = line->chan_in;
296 if (chan && chan->primary) {
297 if (chan->ops->window_size == NULL)
298 return 0;
299 return chan->ops->window_size(chan->fd, chan->data,
300 rows_out, cols_out);
301 }
302 chan = line->chan_out;
303 if (chan && chan->primary) {
304 if (chan->ops->window_size == NULL)
305 return 0;
306 return chan->ops->window_size(chan->fd, chan->data,
307 rows_out, cols_out);
308 }
309 return 0;
310}
311
312static void free_one_chan(struct chan *chan)
313{
314 list_del(entry: &chan->list);
315
316 close_one_chan(chan, delay_free_irq: 0);
317
318 if (chan->ops->free != NULL)
319 (*chan->ops->free)(chan->data);
320
321 if (chan->primary && chan->output)
322 ignore_sigio_fd(chan->fd);
323 kfree(objp: chan);
324}
325
326static void free_chan(struct list_head *chans)
327{
328 struct list_head *ele, *next;
329 struct chan *chan;
330
331 list_for_each_safe(ele, next, chans) {
332 chan = list_entry(ele, struct chan, list);
333 free_one_chan(chan);
334 }
335}
336
337static int one_chan_config_string(struct chan *chan, char *str, int size,
338 char **error_out)
339{
340 int n = 0;
341
342 if (chan == NULL) {
343 CONFIG_CHUNK(str, size, n, "none", 1);
344 return n;
345 }
346
347 CONFIG_CHUNK(str, size, n, chan->ops->type, 0);
348
349 if (chan->dev == NULL) {
350 CONFIG_CHUNK(str, size, n, "", 1);
351 return n;
352 }
353
354 CONFIG_CHUNK(str, size, n, ":", 0);
355 CONFIG_CHUNK(str, size, n, chan->dev, 0);
356
357 return n;
358}
359
360static int chan_pair_config_string(struct chan *in, struct chan *out,
361 char *str, int size, char **error_out)
362{
363 int n;
364
365 n = one_chan_config_string(chan: in, str, size, error_out);
366 str += n;
367 size -= n;
368
369 if (in == out) {
370 CONFIG_CHUNK(str, size, n, "", 1);
371 return n;
372 }
373
374 CONFIG_CHUNK(str, size, n, ",", 1);
375 n = one_chan_config_string(chan: out, str, size, error_out);
376 str += n;
377 size -= n;
378 CONFIG_CHUNK(str, size, n, "", 1);
379
380 return n;
381}
382
383int chan_config_string(struct line *line, char *str, int size,
384 char **error_out)
385{
386 struct chan *in = line->chan_in, *out = line->chan_out;
387
388 if (in && !in->primary)
389 in = NULL;
390 if (out && !out->primary)
391 out = NULL;
392
393 return chan_pair_config_string(in, out, str, size, error_out);
394}
395
396struct chan_type {
397 char *key;
398 const struct chan_ops *ops;
399};
400
401static const struct chan_type chan_table[] = {
402 { "fd", &fd_ops },
403
404#ifdef CONFIG_NULL_CHAN
405 { "null", &null_ops },
406#else
407 { "null", &not_configged_ops },
408#endif
409
410#ifdef CONFIG_PORT_CHAN
411 { "port", &port_ops },
412#else
413 { "port", &not_configged_ops },
414#endif
415
416#ifdef CONFIG_PTY_CHAN
417 { "pty", &pty_ops },
418 { "pts", &pts_ops },
419#else
420 { "pty", &not_configged_ops },
421 { "pts", &not_configged_ops },
422#endif
423
424#ifdef CONFIG_TTY_CHAN
425 { "tty", &tty_ops },
426#else
427 { "tty", &not_configged_ops },
428#endif
429
430#ifdef CONFIG_XTERM_CHAN
431 { "xterm", &xterm_ops },
432#else
433 { "xterm", &not_configged_ops },
434#endif
435};
436
437static struct chan *parse_chan(struct line *line, char *str, int device,
438 const struct chan_opts *opts, char **error_out)
439{
440 const struct chan_type *entry;
441 const struct chan_ops *ops;
442 struct chan *chan;
443 void *data;
444 int i;
445
446 ops = NULL;
447 data = NULL;
448 for(i = 0; i < ARRAY_SIZE(chan_table); i++) {
449 entry = &chan_table[i];
450 if (!strncmp(str, entry->key, strlen(entry->key))) {
451 ops = entry->ops;
452 str += strlen(entry->key);
453 break;
454 }
455 }
456 if (ops == NULL) {
457 *error_out = "No match for configured backends";
458 return NULL;
459 }
460
461 data = (*ops->init)(str, device, opts);
462 if (data == NULL) {
463 *error_out = "Configuration failed";
464 return NULL;
465 }
466
467 chan = kmalloc(size: sizeof(*chan), GFP_ATOMIC);
468 if (chan == NULL) {
469 *error_out = "Memory allocation failed";
470 return NULL;
471 }
472 *chan = ((struct chan) { .list = LIST_HEAD_INIT(chan->list),
473 .free_list =
474 LIST_HEAD_INIT(chan->free_list),
475 .line = line,
476 .primary = 1,
477 .input = 0,
478 .output = 0,
479 .opened = 0,
480 .enabled = 0,
481 .fd = -1,
482 .ops = ops,
483 .data = data });
484 return chan;
485}
486
487int parse_chan_pair(char *str, struct line *line, int device,
488 const struct chan_opts *opts, char **error_out)
489{
490 struct list_head *chans = &line->chan_list;
491 struct chan *new;
492 char *in, *out;
493
494 if (!list_empty(head: chans)) {
495 line->chan_in = line->chan_out = NULL;
496 free_chan(chans);
497 INIT_LIST_HEAD(list: chans);
498 }
499
500 if (!str)
501 return 0;
502
503 out = strchr(str, ',');
504 if (out != NULL) {
505 in = str;
506 *out = '\0';
507 out++;
508 new = parse_chan(line, str: in, device, opts, error_out);
509 if (new == NULL)
510 return -1;
511
512 new->input = 1;
513 list_add(new: &new->list, head: chans);
514 line->chan_in = new;
515
516 new = parse_chan(line, str: out, device, opts, error_out);
517 if (new == NULL)
518 return -1;
519
520 list_add(new: &new->list, head: chans);
521 new->output = 1;
522 line->chan_out = new;
523 }
524 else {
525 new = parse_chan(line, str, device, opts, error_out);
526 if (new == NULL)
527 return -1;
528
529 list_add(new: &new->list, head: chans);
530 new->input = 1;
531 new->output = 1;
532 line->chan_in = line->chan_out = new;
533 }
534 return 0;
535}
536
537void chan_interrupt(struct line *line, int irq)
538{
539 struct tty_port *port = &line->port;
540 struct chan *chan = line->chan_in;
541 int err;
542 u8 c;
543
544 if (!chan || !chan->ops->read)
545 goto out;
546
547 do {
548 if (!tty_buffer_request_room(port, size: 1)) {
549 schedule_delayed_work(dwork: &line->task, delay: 1);
550 goto out;
551 }
552 err = chan->ops->read(chan->fd, &c, chan->data);
553 if (err > 0)
554 tty_insert_flip_char(port, ch: c, TTY_NORMAL);
555 } while (err > 0);
556
557 if (err == -EIO) {
558 if (chan->primary) {
559 tty_port_tty_hangup(port: &line->port, check_clocal: false);
560 if (line->chan_out != chan)
561 close_one_chan(chan: line->chan_out, delay_free_irq: 1);
562 }
563 close_one_chan(chan, delay_free_irq: 1);
564 if (chan->primary)
565 return;
566 }
567 out:
568 tty_flip_buffer_push(port);
569}
570

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