1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6 #include <linux/irqreturn.h>
7 #include <linux/kd.h>
8 #include <linux/sched/signal.h>
9 #include <linux/slab.h>
10
11 #include "chan.h"
12 #include <irq_kern.h>
13 #include <irq_user.h>
14 #include <kern_util.h>
15 #include <os.h>
16
17 #define LINE_BUFSIZE 4096
18
19 static irqreturn_t line_interrupt(int irq, void *data)
20 {
21 struct chan *chan = data;
22 struct line *line = chan->line;
23
24 if (line)
25 chan_interrupt(line, irq);
26
27 return IRQ_HANDLED;
28 }
29
30 /*
31 * Returns the free space inside the ring buffer of this line.
32 *
33 * Should be called while holding line->lock (this does not modify data).
34 */
35 static unsigned int write_room(struct line *line)
36 {
37 int n;
38
39 if (line->buffer == NULL)
40 return LINE_BUFSIZE - 1;
41
42 /* This is for the case where the buffer is wrapped! */
43 n = line->head - line->tail;
44
45 if (n <= 0)
46 n += LINE_BUFSIZE; /* The other case */
47 return n - 1;
48 }
49
50 unsigned int line_write_room(struct tty_struct *tty)
51 {
52 struct line *line = tty->driver_data;
53 unsigned long flags;
54 unsigned int room;
55
56 spin_lock_irqsave(&line->lock, flags);
57 room = write_room(line);
58 spin_unlock_irqrestore(&line->lock, flags);
59
60 return room;
61 }
62
63 unsigned int line_chars_in_buffer(struct tty_struct *tty)
64 {
65 struct line *line = tty->driver_data;
66 unsigned long flags;
67 unsigned int ret;
68
69 spin_lock_irqsave(&line->lock, flags);
70 /* write_room subtracts 1 for the needed NULL, so we readd it.*/
71 ret = LINE_BUFSIZE - (write_room(line) + 1);
72 spin_unlock_irqrestore(&line->lock, flags);
73
74 return ret;
75 }
76
77 /*
78 * This copies the content of buf into the circular buffer associated with
79 * this line.
80 * The return value is the number of characters actually copied, i.e. the ones
81 * for which there was space: this function is not supposed to ever flush out
82 * the circular buffer.
83 *
84 * Must be called while holding line->lock!
85 */
86 static int buffer_data(struct line *line, const u8 *buf, size_t len)
87 {
88 int end, room;
89
90 if (line->buffer == NULL) {
91 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
92 if (line->buffer == NULL) {
93 printk(KERN_ERR "buffer_data - atomic allocation "
94 "failed\n");
95 return 0;
96 }
97 line->head = line->buffer;
98 line->tail = line->buffer;
99 }
100
101 room = write_room(line);
102 len = (len > room) ? room : len;
103
104 end = line->buffer + LINE_BUFSIZE - line->tail;
105
106 if (len < end) {
107 memcpy(line->tail, buf, len);
108 line->tail += len;
109 }
110 else {
111 /* The circular buffer is wrapping */
112 memcpy(line->tail, buf, end);
113 buf += end;
114 memcpy(line->buffer, buf, len - end);
115 line->tail = line->buffer + len - end;
116 }
117
118 return len;
119 }
120
121 /*
122 * Flushes the ring buffer to the output channels. That is, write_chan is
123 * called, passing it line->head as buffer, and an appropriate count.
124 *
125 * On exit, returns 1 when the buffer is empty,
126 * 0 when the buffer is not empty on exit,
127 * and -errno when an error occurred.
128 *
129 * Must be called while holding line->lock!*/
130 static int flush_buffer(struct line *line)
131 {
132 int n, count;
133
134 if ((line->buffer == NULL) || (line->head == line->tail))
135 return 1;
136
137 if (line->tail < line->head) {
138 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
139 count = line->buffer + LINE_BUFSIZE - line->head;
140
141 n = write_chan(line->chan_out, line->head, count,
142 line->write_irq);
143 if (n < 0)
144 return n;
145 if (n == count) {
146 /*
147 * We have flushed from ->head to buffer end, now we
148 * must flush only from the beginning to ->tail.
149 */
150 line->head = line->buffer;
151 } else {
152 line->head += n;
153 return 0;
154 }
155 }
156
157 count = line->tail - line->head;
158 n = write_chan(line->chan_out, line->head, count,
159 line->write_irq);
160
161 if (n < 0)
162 return n;
163
164 line->head += n;
165 return line->head == line->tail;
166 }
167
168 void line_flush_buffer(struct tty_struct *tty)
169 {
170 struct line *line = tty->driver_data;
171 unsigned long flags;
172
173 spin_lock_irqsave(&line->lock, flags);
174 flush_buffer(line);
175 spin_unlock_irqrestore(&line->lock, flags);
176 }
177
178 /*
179 * We map both ->flush_chars and ->put_char (which go in pair) onto
180 * ->flush_buffer and ->write. Hope it's not that bad.
181 */
182 void line_flush_chars(struct tty_struct *tty)
183 {
184 line_flush_buffer(tty);
185 }
186
187 ssize_t line_write(struct tty_struct *tty, const u8 *buf, size_t len)
188 {
189 struct line *line = tty->driver_data;
190 unsigned long flags;
191 int n, ret = 0;
192
193 spin_lock_irqsave(&line->lock, flags);
194 if (line->head != line->tail)
195 ret = buffer_data(line, buf, len);
196 else {
197 n = write_chan(line->chan_out, buf, len,
198 line->write_irq);
199 if (n < 0) {
200 ret = n;
201 goto out_up;
202 }
203
204 len -= n;
205 ret += n;
206 if (len > 0)
207 ret += buffer_data(line, buf + n, len);
208 }
209 out_up:
210 spin_unlock_irqrestore(&line->lock, flags);
211 return ret;
212 }
213
214 void line_throttle(struct tty_struct *tty)
215 {
216 struct line *line = tty->driver_data;
217
218 deactivate_chan(line->chan_in, line->read_irq);
219 line->throttled = 1;
220 }
221
222 void line_unthrottle(struct tty_struct *tty)
223 {
224 struct line *line = tty->driver_data;
225
226 line->throttled = 0;
227 chan_interrupt(line, line->read_irq);
228 }
229
230 static irqreturn_t line_write_interrupt(int irq, void *data)
231 {
232 struct chan *chan = data;
233 struct line *line = chan->line;
234 int err;
235
236 /*
237 * Interrupts are disabled here because genirq keep irqs disabled when
238 * calling the action handler.
239 */
240
241 spin_lock(&line->lock);
242 err = flush_buffer(line);
243 if (err == 0) {
244 spin_unlock(&line->lock);
245 return IRQ_NONE;
246 } else if ((err < 0) && (err != -EAGAIN)) {
247 line->head = line->buffer;
248 line->tail = line->buffer;
249 }
250 spin_unlock(&line->lock);
251
252 tty_port_tty_wakeup(&line->port);
253
254 return IRQ_HANDLED;
255 }
256
257 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
258 {
259 const struct line_driver *driver = line->driver;
260 int err;
261
262 if (input) {
263 err = um_request_irq(UM_IRQ_ALLOC, fd, IRQ_READ,
264 line_interrupt, 0,
265 driver->read_irq_name, data);
266 if (err < 0)
267 return err;
268
269 line->read_irq = err;
270 }
271
272 if (output) {
273 err = um_request_irq(UM_IRQ_ALLOC, fd, IRQ_WRITE,
274 line_write_interrupt, 0,
275 driver->write_irq_name, data);
276 if (err < 0)
277 return err;
278
279 line->write_irq = err;
280 }
281
282 return 0;
283 }
284
285 static int line_activate(struct tty_port *port, struct tty_struct *tty)
286 {
287 int ret;
288 struct line *line = tty->driver_data;
289
290 ret = enable_chan(line);
291 if (ret)
292 return ret;
293
294 if (!line->sigio) {
295 chan_enable_winch(line->chan_out, port);
296 line->sigio = 1;
297 }
298
299 chan_window_size(line, &tty->winsize.ws_row,
300 &tty->winsize.ws_col);
301
302 return 0;
303 }
304
305 static void unregister_winch(struct tty_struct *tty);
306
307 static void line_destruct(struct tty_port *port)
308 {
309 struct tty_struct *tty = tty_port_tty_get(port);
310 struct line *line = tty->driver_data;
311
312 if (line->sigio) {
313 unregister_winch(tty);
314 line->sigio = 0;
315 }
316 }
317
318 static const struct tty_port_operations line_port_ops = {
319 .activate = line_activate,
320 .destruct = line_destruct,
321 };
322
323 int line_open(struct tty_struct *tty, struct file *filp)
324 {
325 struct line *line = tty->driver_data;
326
327 return tty_port_open(&line->port, tty, filp);
328 }
329
330 int line_install(struct tty_driver *driver, struct tty_struct *tty,
331 struct line *line)
332 {
333 int ret;
334
335 ret = tty_standard_install(driver, tty);
336 if (ret)
337 return ret;
338
339 tty->driver_data = line;
340
341 return 0;
342 }
343
344 void line_close(struct tty_struct *tty, struct file * filp)
345 {
346 struct line *line = tty->driver_data;
347
348 tty_port_close(&line->port, tty, filp);
349 }
350
351 void line_hangup(struct tty_struct *tty)
352 {
353 struct line *line = tty->driver_data;
354
355 tty_port_hangup(&line->port);
356 }
357
358 void close_lines(struct line *lines, int nlines)
359 {
360 int i;
361
362 for(i = 0; i < nlines; i++)
363 close_chan(&lines[i]);
364 }
365
366 int setup_one_line(struct line *lines, int n, char *init,
367 const struct chan_opts *opts, char **error_out)
368 {
369 struct line *line = &lines[n];
370 struct tty_driver *driver = line->driver->driver;
371 int err = -EINVAL;
372
373 if (line->port.count) {
374 *error_out = "Device is already open";
375 goto out;
376 }
377
378 if (!strcmp(init, "none")) {
379 if (line->valid) {
380 line->valid = 0;
381 kfree(line->init_str);
382 tty_unregister_device(driver, n);
383 parse_chan_pair(NULL, line, n, opts, error_out);
384 err = 0;
385 }
386 *error_out = "configured as 'none'";
387 } else {
388 char *new = kstrdup(init, GFP_KERNEL);
389 if (!new) {
390 *error_out = "Failed to allocate memory";
391 return -ENOMEM;
392 }
393 if (line->valid) {
394 tty_unregister_device(driver, n);
395 kfree(line->init_str);
396 }
397 line->init_str = new;
398 line->valid = 1;
399 err = parse_chan_pair(new, line, n, opts, error_out);
400 if (!err) {
401 struct device *d = tty_port_register_device(&line->port,
402 driver, n, NULL);
403 if (IS_ERR(d)) {
404 *error_out = "Failed to register device";
405 err = PTR_ERR(d);
406 parse_chan_pair(NULL, line, n, opts, error_out);
407 }
408 }
409 if (err) {
410 *error_out = "failed to parse channel pair";
411 line->init_str = NULL;
412 line->valid = 0;
413 kfree(new);
414 }
415 }
416 out:
417 return err;
418 }
419
420 /*
421 * Common setup code for both startup command line and mconsole initialization.
422 * @lines contains the array (of size @num) to modify;
423 * @init is the setup string;
424 * @error_out is an error string in the case of failure;
425 */
426
427 int line_setup(char **conf, unsigned int num, char **def,
428 char *init, char *name)
429 {
430 char *error;
431
432 if (*init == '=') {
433 /*
434 * We said con=/ssl= instead of con#=, so we are configuring all
435 * consoles at once.
436 */
437 *def = init + 1;
438 } else {
439 char *end;
440 unsigned n = simple_strtoul(init, &end, 0);
441
442 if (*end != '=') {
443 error = "Couldn't parse device number";
444 goto out;
445 }
446 if (n >= num) {
447 error = "Device number out of range";
448 goto out;
449 }
450 conf[n] = end + 1;
451 }
452 return 0;
453
454 out:
455 printk(KERN_ERR "Failed to set up %s with "
456 "configuration string \"%s\" : %s\n", name, init, error);
457 return -EINVAL;
458 }
459
460 int line_config(struct line *lines, unsigned int num, char *str,
461 const struct chan_opts *opts, char **error_out)
462 {
463 char *end;
464 int n;
465
466 if (*str == '=') {
467 *error_out = "Can't configure all devices from mconsole";
468 return -EINVAL;
469 }
470
471 n = simple_strtoul(str, &end, 0);
472 if (*end++ != '=') {
473 *error_out = "Couldn't parse device number";
474 return -EINVAL;
475 }
476 if (n >= num) {
477 *error_out = "Device number out of range";
478 return -EINVAL;
479 }
480
481 return setup_one_line(lines, n, end, opts, error_out);
482 }
483
484 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
485 int size, char **error_out)
486 {
487 struct line *line;
488 char *end;
489 int dev, n = 0;
490
491 dev = simple_strtoul(name, &end, 0);
492 if ((*end != '\0') || (end == name)) {
493 *error_out = "line_get_config failed to parse device number";
494 return 0;
495 }
496
497 if ((dev < 0) || (dev >= num)) {
498 *error_out = "device number out of range";
499 return 0;
500 }
501
502 line = &lines[dev];
503
504 if (!line->valid)
505 CONFIG_CHUNK(str, size, n, "none", 1);
506 else {
507 struct tty_struct *tty = tty_port_tty_get(&line->port);
508 if (tty == NULL) {
509 CONFIG_CHUNK(str, size, n, line->init_str, 1);
510 } else {
511 n = chan_config_string(line, str, size, error_out);
512 tty_kref_put(tty);
513 }
514 }
515
516 return n;
517 }
518
519 int line_id(char **str, int *start_out, int *end_out)
520 {
521 char *end;
522 int n;
523
524 n = simple_strtoul(*str, &end, 0);
525 if ((*end != '\0') || (end == *str))
526 return -1;
527
528 *str = end;
529 *start_out = n;
530 *end_out = n;
531 return n;
532 }
533
534 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
535 {
536 if (n >= num) {
537 *error_out = "Device number out of range";
538 return -EINVAL;
539 }
540 return setup_one_line(lines, n, "none", NULL, error_out);
541 }
542
543 int register_lines(struct line_driver *line_driver,
544 const struct tty_operations *ops,
545 struct line *lines, int nlines)
546 {
547 struct tty_driver *driver;
548 int err;
549 int i;
550
551 driver = tty_alloc_driver(nlines, TTY_DRIVER_REAL_RAW |
552 TTY_DRIVER_DYNAMIC_DEV);
553 if (IS_ERR(driver))
554 return PTR_ERR(driver);
555
556 driver->driver_name = line_driver->name;
557 driver->name = line_driver->device_name;
558 driver->major = line_driver->major;
559 driver->minor_start = line_driver->minor_start;
560 driver->type = line_driver->type;
561 driver->subtype = line_driver->subtype;
562 driver->init_termios = tty_std_termios;
563
564 for (i = 0; i < nlines; i++) {
565 tty_port_init(&lines[i].port);
566 lines[i].port.ops = &line_port_ops;
567 spin_lock_init(&lines[i].lock);
568 lines[i].driver = line_driver;
569 INIT_LIST_HEAD(&lines[i].chan_list);
570 }
571 tty_set_operations(driver, ops);
572
573 err = tty_register_driver(driver);
574 if (err) {
575 printk(KERN_ERR "register_lines : can't register %s driver\n",
576 line_driver->name);
577 tty_driver_kref_put(driver);
578 for (i = 0; i < nlines; i++)
579 tty_port_destroy(&lines[i].port);
580 return err;
581 }
582
583 line_driver->driver = driver;
584 mconsole_register_dev(&line_driver->mc);
585 return 0;
586 }
587
588 static DEFINE_SPINLOCK(winch_handler_lock);
589 static LIST_HEAD(winch_handlers);
590
591 struct winch {
592 struct list_head list;
593 int fd;
594 int tty_fd;
595 int pid;
596 struct tty_port *port;
597 unsigned long stack;
598 struct work_struct work;
599 };
600
601 static void __free_winch(struct work_struct *work)
602 {
603 struct winch *winch = container_of(work, struct winch, work);
604 um_free_irq(WINCH_IRQ, winch);
605
606 if (winch->pid != -1)
607 os_kill_process(winch->pid, 1);
608 if (winch->stack != 0)
609 free_stack(winch->stack, 0);
610 kfree(winch);
611 }
612
613 static void free_winch(struct winch *winch)
614 {
615 int fd = winch->fd;
616 winch->fd = -1;
617 if (fd != -1)
618 os_close_file(fd);
619 __free_winch(&winch->work);
620 }
621
622 static irqreturn_t winch_interrupt(int irq, void *data)
623 {
624 struct winch *winch = data;
625 struct tty_struct *tty;
626 struct line *line;
627 int fd = winch->fd;
628 int err;
629 char c;
630 struct pid *pgrp;
631
632 if (fd != -1) {
633 err = generic_read(fd, &c, NULL);
634 /* A read of 2 means the winch thread failed and has warned */
635 if (err < 0 || (err == 1 && c == 2)) {
636 if (err != -EAGAIN) {
637 winch->fd = -1;
638 list_del(&winch->list);
639 os_close_file(fd);
640 if (err < 0) {
641 printk(KERN_ERR "winch_interrupt : read failed, errno = %d\n",
642 -err);
643 printk(KERN_ERR "fd %d is losing SIGWINCH support\n",
644 winch->tty_fd);
645 }
646 INIT_WORK(&winch->work, __free_winch);
647 schedule_work(&winch->work);
648 return IRQ_HANDLED;
649 }
650 goto out;
651 }
652 }
653 tty = tty_port_tty_get(winch->port);
654 if (tty != NULL) {
655 line = tty->driver_data;
656 if (line != NULL) {
657 chan_window_size(line, &tty->winsize.ws_row,
658 &tty->winsize.ws_col);
659 pgrp = tty_get_pgrp(tty);
660 if (pgrp)
661 kill_pgrp(pgrp, SIGWINCH, 1);
662 put_pid(pgrp);
663 }
664 tty_kref_put(tty);
665 }
666 out:
667 return IRQ_HANDLED;
668 }
669
670 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_port *port,
671 unsigned long stack)
672 {
673 struct winch *winch;
674
675 winch = kmalloc(sizeof(*winch), GFP_KERNEL);
676 if (winch == NULL) {
677 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
678 goto cleanup;
679 }
680
681 *winch = ((struct winch) { .fd = fd,
682 .tty_fd = tty_fd,
683 .pid = pid,
684 .port = port,
685 .stack = stack });
686
687 spin_lock(&winch_handler_lock);
688 list_add(&winch->list, &winch_handlers);
689 spin_unlock(&winch_handler_lock);
690
691 if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
692 IRQF_SHARED, "winch", winch) < 0) {
693 printk(KERN_ERR "register_winch_irq - failed to register "
694 "IRQ\n");
695 spin_lock(&winch_handler_lock);
696 list_del(&winch->list);
697 spin_unlock(&winch_handler_lock);
698 goto out_free;
699 }
700
701 return;
702
703 out_free:
704 kfree(winch);
705 cleanup:
706 os_kill_process(pid, 1);
707 os_close_file(fd);
708 if (stack != 0)
709 free_stack(stack, 0);
710 }
711
712 static void unregister_winch(struct tty_struct *tty)
713 {
714 struct list_head *ele, *next;
715 struct winch *winch;
716 struct tty_struct *wtty;
717
718 spin_lock(&winch_handler_lock);
719
720 list_for_each_safe(ele, next, &winch_handlers) {
721 winch = list_entry(ele, struct winch, list);
722 wtty = tty_port_tty_get(winch->port);
723 if (wtty == tty) {
724 list_del(&winch->list);
725 spin_unlock(&winch_handler_lock);
726 free_winch(winch);
727 break;
728 }
729 tty_kref_put(wtty);
730 }
731 spin_unlock(&winch_handler_lock);
732 }
733
734 static void winch_cleanup(void)
735 {
736 struct winch *winch;
737
738 spin_lock(&winch_handler_lock);
739 while ((winch = list_first_entry_or_null(&winch_handlers,
740 struct winch, list))) {
741 list_del(&winch->list);
742 spin_unlock(&winch_handler_lock);
743
744 free_winch(winch);
745
746 spin_lock(&winch_handler_lock);
747 }
748
749 spin_unlock(&winch_handler_lock);
750 }
751 __uml_exitcall(winch_cleanup);
752
753 char *add_xterm_umid(char *base)
754 {
755 char *umid, *title;
756 int len;
757
758 umid = get_umid();
759 if (*umid == '\0')
760 return base;
761
762 len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
763 title = kmalloc(len, GFP_KERNEL);
764 if (title == NULL) {
765 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
766 return base;
767 }
768
769 snprintf(title, len, "%s (%s)", base, umid);
770 return title;
771 }
772
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