14a102e877d66e51a1e28a4f5a64ce23b509050a
[linux-2.6.git] / arch / um / drivers / line.c
1 /*
2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5
6 #include "linux/irqreturn.h"
7 #include "linux/kd.h"
8 #include "chan_kern.h"
9 #include "irq_kern.h"
10 #include "irq_user.h"
11 #include "kern_util.h"
12 #include "os.h"
13
14 #define LINE_BUFSIZE 4096
15
16 static irqreturn_t line_interrupt(int irq, void *data)
17 {
18         struct chan *chan = data;
19         struct line *line = chan->line;
20         struct tty_struct *tty = line->tty;
21
22         if (line)
23                 chan_interrupt(&line->chan_list, &line->task, tty, irq);
24         return IRQ_HANDLED;
25 }
26
27 static void line_timer_cb(struct work_struct *work)
28 {
29         struct line *line = container_of(work, struct line, task.work);
30
31         if (!line->throttled)
32                 chan_interrupt(&line->chan_list, &line->task, line->tty,
33                                line->driver->read_irq);
34 }
35
36 /*
37  * Returns the free space inside the ring buffer of this line.
38  *
39  * Should be called while holding line->lock (this does not modify data).
40  */
41 static int write_room(struct line *line)
42 {
43         int n;
44
45         if (line->buffer == NULL)
46                 return LINE_BUFSIZE - 1;
47
48         /* This is for the case where the buffer is wrapped! */
49         n = line->head - line->tail;
50
51         if (n <= 0)
52                 n += LINE_BUFSIZE; /* The other case */
53         return n - 1;
54 }
55
56 int line_write_room(struct tty_struct *tty)
57 {
58         struct line *line = tty->driver_data;
59         unsigned long flags;
60         int room;
61
62         spin_lock_irqsave(&line->lock, flags);
63         room = write_room(line);
64         spin_unlock_irqrestore(&line->lock, flags);
65
66         return room;
67 }
68
69 int line_chars_in_buffer(struct tty_struct *tty)
70 {
71         struct line *line = tty->driver_data;
72         unsigned long flags;
73         int ret;
74
75         spin_lock_irqsave(&line->lock, flags);
76         /* write_room subtracts 1 for the needed NULL, so we readd it.*/
77         ret = LINE_BUFSIZE - (write_room(line) + 1);
78         spin_unlock_irqrestore(&line->lock, flags);
79
80         return ret;
81 }
82
83 /*
84  * This copies the content of buf into the circular buffer associated with
85  * this line.
86  * The return value is the number of characters actually copied, i.e. the ones
87  * for which there was space: this function is not supposed to ever flush out
88  * the circular buffer.
89  *
90  * Must be called while holding line->lock!
91  */
92 static int buffer_data(struct line *line, const char *buf, int len)
93 {
94         int end, room;
95
96         if (line->buffer == NULL) {
97                 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
98                 if (line->buffer == NULL) {
99                         printk(KERN_ERR "buffer_data - atomic allocation "
100                                "failed\n");
101                         return 0;
102                 }
103                 line->head = line->buffer;
104                 line->tail = line->buffer;
105         }
106
107         room = write_room(line);
108         len = (len > room) ? room : len;
109
110         end = line->buffer + LINE_BUFSIZE - line->tail;
111
112         if (len < end) {
113                 memcpy(line->tail, buf, len);
114                 line->tail += len;
115         }
116         else {
117                 /* The circular buffer is wrapping */
118                 memcpy(line->tail, buf, end);
119                 buf += end;
120                 memcpy(line->buffer, buf, len - end);
121                 line->tail = line->buffer + len - end;
122         }
123
124         return len;
125 }
126
127 /*
128  * Flushes the ring buffer to the output channels. That is, write_chan is
129  * called, passing it line->head as buffer, and an appropriate count.
130  *
131  * On exit, returns 1 when the buffer is empty,
132  * 0 when the buffer is not empty on exit,
133  * and -errno when an error occurred.
134  *
135  * Must be called while holding line->lock!*/
136 static int flush_buffer(struct line *line)
137 {
138         int n, count;
139
140         if ((line->buffer == NULL) || (line->head == line->tail))
141                 return 1;
142
143         if (line->tail < line->head) {
144                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
145                 count = line->buffer + LINE_BUFSIZE - line->head;
146
147                 n = write_chan(&line->chan_list, line->head, count,
148                                line->driver->write_irq);
149                 if (n < 0)
150                         return n;
151                 if (n == count) {
152                         /*
153                          * We have flushed from ->head to buffer end, now we
154                          * must flush only from the beginning to ->tail.
155                          */
156                         line->head = line->buffer;
157                 } else {
158                         line->head += n;
159                         return 0;
160                 }
161         }
162
163         count = line->tail - line->head;
164         n = write_chan(&line->chan_list, line->head, count,
165                        line->driver->write_irq);
166
167         if (n < 0)
168                 return n;
169
170         line->head += n;
171         return line->head == line->tail;
172 }
173
174 void line_flush_buffer(struct tty_struct *tty)
175 {
176         struct line *line = tty->driver_data;
177         unsigned long flags;
178         int err;
179
180         spin_lock_irqsave(&line->lock, flags);
181         err = flush_buffer(line);
182         spin_unlock_irqrestore(&line->lock, flags);
183 }
184
185 /*
186  * We map both ->flush_chars and ->put_char (which go in pair) onto
187  * ->flush_buffer and ->write. Hope it's not that bad.
188  */
189 void line_flush_chars(struct tty_struct *tty)
190 {
191         line_flush_buffer(tty);
192 }
193
194 int line_put_char(struct tty_struct *tty, unsigned char ch)
195 {
196         return line_write(tty, &ch, sizeof(ch));
197 }
198
199 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
200 {
201         struct line *line = tty->driver_data;
202         unsigned long flags;
203         int n, ret = 0;
204
205         spin_lock_irqsave(&line->lock, flags);
206         if (line->head != line->tail)
207                 ret = buffer_data(line, buf, len);
208         else {
209                 n = write_chan(&line->chan_list, buf, len,
210                                line->driver->write_irq);
211                 if (n < 0) {
212                         ret = n;
213                         goto out_up;
214                 }
215
216                 len -= n;
217                 ret += n;
218                 if (len > 0)
219                         ret += buffer_data(line, buf + n, len);
220         }
221 out_up:
222         spin_unlock_irqrestore(&line->lock, flags);
223         return ret;
224 }
225
226 void line_set_termios(struct tty_struct *tty, struct ktermios * old)
227 {
228         /* nothing */
229 }
230
231 static const struct {
232         int  cmd;
233         char *level;
234         char *name;
235 } tty_ioctls[] = {
236         /* don't print these, they flood the log ... */
237         { TCGETS,      NULL,       "TCGETS"      },
238         { TCSETS,      NULL,       "TCSETS"      },
239         { TCSETSW,     NULL,       "TCSETSW"     },
240         { TCFLSH,      NULL,       "TCFLSH"      },
241         { TCSBRK,      NULL,       "TCSBRK"      },
242
243         /* general tty stuff */
244         { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
245         { TCGETA,      KERN_DEBUG, "TCGETA"      },
246         { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
247         { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
248         { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
249
250         /* linux-specific ones */
251         { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
252         { KDGKBMODE,   KERN_INFO,  "KDGKBMODE"   },
253         { KDGKBTYPE,   KERN_INFO,  "KDGKBTYPE"   },
254         { KDSIGACCEPT, KERN_INFO,  "KDSIGACCEPT" },
255 };
256
257 int line_ioctl(struct tty_struct *tty, struct file * file,
258                unsigned int cmd, unsigned long arg)
259 {
260         int ret;
261         int i;
262
263         ret = 0;
264         switch(cmd) {
265 #ifdef TIOCGETP
266         case TIOCGETP:
267         case TIOCSETP:
268         case TIOCSETN:
269 #endif
270 #ifdef TIOCGETC
271         case TIOCGETC:
272         case TIOCSETC:
273 #endif
274 #ifdef TIOCGLTC
275         case TIOCGLTC:
276         case TIOCSLTC:
277 #endif
278         /* Note: these are out of date as we now have TCGETS2 etc but this
279            whole lot should probably go away */
280         case TCGETS:
281         case TCSETSF:
282         case TCSETSW:
283         case TCSETS:
284         case TCGETA:
285         case TCSETAF:
286         case TCSETAW:
287         case TCSETA:
288         case TCXONC:
289         case TCFLSH:
290         case TIOCOUTQ:
291         case TIOCINQ:
292         case TIOCGLCKTRMIOS:
293         case TIOCSLCKTRMIOS:
294         case TIOCPKT:
295         case TIOCGSOFTCAR:
296         case TIOCSSOFTCAR:
297                 return -ENOIOCTLCMD;
298 #if 0
299         case TCwhatever:
300                 /* do something */
301                 break;
302 #endif
303         default:
304                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
305                         if (cmd == tty_ioctls[i].cmd)
306                                 break;
307                 if (i == ARRAY_SIZE(tty_ioctls)) {
308                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
309                                __func__, tty->name, cmd);
310                 }
311                 ret = -ENOIOCTLCMD;
312                 break;
313         }
314         return ret;
315 }
316
317 void line_throttle(struct tty_struct *tty)
318 {
319         struct line *line = tty->driver_data;
320
321         deactivate_chan(&line->chan_list, line->driver->read_irq);
322         line->throttled = 1;
323 }
324
325 void line_unthrottle(struct tty_struct *tty)
326 {
327         struct line *line = tty->driver_data;
328
329         line->throttled = 0;
330         chan_interrupt(&line->chan_list, &line->task, tty,
331                        line->driver->read_irq);
332
333         /*
334          * Maybe there is enough stuff pending that calling the interrupt
335          * throttles us again.  In this case, line->throttled will be 1
336          * again and we shouldn't turn the interrupt back on.
337          */
338         if (!line->throttled)
339                 reactivate_chan(&line->chan_list, line->driver->read_irq);
340 }
341
342 static irqreturn_t line_write_interrupt(int irq, void *data)
343 {
344         struct chan *chan = data;
345         struct line *line = chan->line;
346         struct tty_struct *tty = line->tty;
347         int err;
348
349         /*
350          * Interrupts are disabled here because we registered the interrupt with
351          * IRQF_DISABLED (see line_setup_irq).
352          */
353
354         spin_lock(&line->lock);
355         err = flush_buffer(line);
356         if (err == 0) {
357                 return IRQ_NONE;
358         } else if (err < 0) {
359                 line->head = line->buffer;
360                 line->tail = line->buffer;
361         }
362         spin_unlock(&line->lock);
363
364         if (tty == NULL)
365                 return IRQ_NONE;
366
367         tty_wakeup(tty);
368         return IRQ_HANDLED;
369 }
370
371 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
372 {
373         const struct line_driver *driver = line->driver;
374         int err = 0, flags = IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM;
375
376         if (input)
377                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
378                                        line_interrupt, flags,
379                                        driver->read_irq_name, data);
380         if (err)
381                 return err;
382         if (output)
383                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
384                                         line_write_interrupt, flags,
385                                         driver->write_irq_name, data);
386         line->have_irq = 1;
387         return err;
388 }
389
390 /*
391  * Normally, a driver like this can rely mostly on the tty layer
392  * locking, particularly when it comes to the driver structure.
393  * However, in this case, mconsole requests can come in "from the
394  * side", and race with opens and closes.
395  *
396  * mconsole config requests will want to be sure the device isn't in
397  * use, and get_config, open, and close will want a stable
398  * configuration.  The checking and modification of the configuration
399  * is done under a spinlock.  Checking whether the device is in use is
400  * line->tty->count > 1, also under the spinlock.
401  *
402  * tty->count serves to decide whether the device should be enabled or
403  * disabled on the host.  If it's equal to 1, then we are doing the
404  * first open or last close.  Otherwise, open and close just return.
405  */
406
407 int line_open(struct line *lines, struct tty_struct *tty)
408 {
409         struct line *line = &lines[tty->index];
410         int err = -ENODEV;
411
412         spin_lock(&line->count_lock);
413         if (!line->valid)
414                 goto out_unlock;
415
416         err = 0;
417         if (tty->count > 1)
418                 goto out_unlock;
419
420         spin_unlock(&line->count_lock);
421
422         tty->driver_data = line;
423         line->tty = tty;
424
425         err = enable_chan(line);
426         if (err)
427                 return err;
428
429         INIT_DELAYED_WORK(&line->task, line_timer_cb);
430
431         if (!line->sigio) {
432                 chan_enable_winch(&line->chan_list, tty);
433                 line->sigio = 1;
434         }
435
436         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
437                          &tty->winsize.ws_col);
438
439         return err;
440
441 out_unlock:
442         spin_unlock(&line->count_lock);
443         return err;
444 }
445
446 static void unregister_winch(struct tty_struct *tty);
447
448 void line_close(struct tty_struct *tty, struct file * filp)
449 {
450         struct line *line = tty->driver_data;
451
452         /*
453          * If line_open fails (and tty->driver_data is never set),
454          * tty_open will call line_close.  So just return in this case.
455          */
456         if (line == NULL)
457                 return;
458
459         /* We ignore the error anyway! */
460         flush_buffer(line);
461
462         spin_lock(&line->count_lock);
463         if (!line->valid)
464                 goto out_unlock;
465
466         if (tty->count > 1)
467                 goto out_unlock;
468
469         spin_unlock(&line->count_lock);
470
471         line->tty = NULL;
472         tty->driver_data = NULL;
473
474         if (line->sigio) {
475                 unregister_winch(tty);
476                 line->sigio = 0;
477         }
478
479         return;
480
481 out_unlock:
482         spin_unlock(&line->count_lock);
483 }
484
485 void close_lines(struct line *lines, int nlines)
486 {
487         int i;
488
489         for(i = 0; i < nlines; i++)
490                 close_chan(&lines[i].chan_list, 0);
491 }
492
493 static int setup_one_line(struct line *lines, int n, char *init, int init_prio,
494                           char **error_out)
495 {
496         struct line *line = &lines[n];
497         int err = -EINVAL;
498
499         spin_lock(&line->count_lock);
500
501         if (line->tty != NULL) {
502                 *error_out = "Device is already open";
503                 goto out;
504         }
505
506         if (line->init_pri <= init_prio) {
507                 line->init_pri = init_prio;
508                 if (!strcmp(init, "none"))
509                         line->valid = 0;
510                 else {
511                         line->init_str = init;
512                         line->valid = 1;
513                 }
514         }
515         err = 0;
516 out:
517         spin_unlock(&line->count_lock);
518         return err;
519 }
520
521 /*
522  * Common setup code for both startup command line and mconsole initialization.
523  * @lines contains the array (of size @num) to modify;
524  * @init is the setup string;
525  * @error_out is an error string in the case of failure;
526  */
527
528 int line_setup(struct line *lines, unsigned int num, char *init,
529                char **error_out)
530 {
531         int i, n, err;
532         char *end;
533
534         if (*init == '=') {
535                 /*
536                  * We said con=/ssl= instead of con#=, so we are configuring all
537                  * consoles at once.
538                  */
539                 n = -1;
540         }
541         else {
542                 n = simple_strtoul(init, &end, 0);
543                 if (*end != '=') {
544                         *error_out = "Couldn't parse device number";
545                         return -EINVAL;
546                 }
547                 init = end;
548         }
549         init++;
550
551         if (n >= (signed int) num) {
552                 *error_out = "Device number out of range";
553                 return -EINVAL;
554         }
555         else if (n >= 0) {
556                 err = setup_one_line(lines, n, init, INIT_ONE, error_out);
557                 if (err)
558                         return err;
559         }
560         else {
561                 for(i = 0; i < num; i++) {
562                         err = setup_one_line(lines, i, init, INIT_ALL,
563                                              error_out);
564                         if (err)
565                                 return err;
566                 }
567         }
568         return n == -1 ? num : n;
569 }
570
571 int line_config(struct line *lines, unsigned int num, char *str,
572                 const struct chan_opts *opts, char **error_out)
573 {
574         struct line *line;
575         char *new;
576         int n;
577
578         if (*str == '=') {
579                 *error_out = "Can't configure all devices from mconsole";
580                 return -EINVAL;
581         }
582
583         new = kstrdup(str, GFP_KERNEL);
584         if (new == NULL) {
585                 *error_out = "Failed to allocate memory";
586                 return -ENOMEM;
587         }
588         n = line_setup(lines, num, new, error_out);
589         if (n < 0)
590                 return n;
591
592         line = &lines[n];
593         return parse_chan_pair(line->init_str, line, n, opts, error_out);
594 }
595
596 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
597                     int size, char **error_out)
598 {
599         struct line *line;
600         char *end;
601         int dev, n = 0;
602
603         dev = simple_strtoul(name, &end, 0);
604         if ((*end != '\0') || (end == name)) {
605                 *error_out = "line_get_config failed to parse device number";
606                 return 0;
607         }
608
609         if ((dev < 0) || (dev >= num)) {
610                 *error_out = "device number out of range";
611                 return 0;
612         }
613
614         line = &lines[dev];
615
616         spin_lock(&line->count_lock);
617         if (!line->valid)
618                 CONFIG_CHUNK(str, size, n, "none", 1);
619         else if (line->tty == NULL)
620                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
621         else n = chan_config_string(&line->chan_list, str, size, error_out);
622         spin_unlock(&line->count_lock);
623
624         return n;
625 }
626
627 int line_id(char **str, int *start_out, int *end_out)
628 {
629         char *end;
630         int n;
631
632         n = simple_strtoul(*str, &end, 0);
633         if ((*end != '\0') || (end == *str))
634                 return -1;
635
636         *str = end;
637         *start_out = n;
638         *end_out = n;
639         return n;
640 }
641
642 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
643 {
644         int err;
645         char config[sizeof("conxxxx=none\0")];
646
647         sprintf(config, "%d=none", n);
648         err = line_setup(lines, num, config, error_out);
649         if (err >= 0)
650                 err = 0;
651         return err;
652 }
653
654 struct tty_driver *register_lines(struct line_driver *line_driver,
655                                   const struct tty_operations *ops,
656                                   struct line *lines, int nlines)
657 {
658         int i;
659         struct tty_driver *driver = alloc_tty_driver(nlines);
660
661         if (!driver)
662                 return NULL;
663
664         driver->driver_name = line_driver->name;
665         driver->name = line_driver->device_name;
666         driver->major = line_driver->major;
667         driver->minor_start = line_driver->minor_start;
668         driver->type = line_driver->type;
669         driver->subtype = line_driver->subtype;
670         driver->flags = TTY_DRIVER_REAL_RAW;
671         driver->init_termios = tty_std_termios;
672         tty_set_operations(driver, ops);
673
674         if (tty_register_driver(driver)) {
675                 printk(KERN_ERR "register_lines : can't register %s driver\n",
676                        line_driver->name);
677                 put_tty_driver(driver);
678                 return NULL;
679         }
680
681         for(i = 0; i < nlines; i++) {
682                 if (!lines[i].valid)
683                         tty_unregister_device(driver, i);
684         }
685
686         mconsole_register_dev(&line_driver->mc);
687         return driver;
688 }
689
690 static DEFINE_SPINLOCK(winch_handler_lock);
691 static LIST_HEAD(winch_handlers);
692
693 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
694 {
695         struct line *line;
696         char *error;
697         int i;
698
699         for(i = 0; i < nlines; i++) {
700                 line = &lines[i];
701                 INIT_LIST_HEAD(&line->chan_list);
702
703                 if (line->init_str == NULL)
704                         continue;
705
706                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
707                 if (line->init_str == NULL)
708                         printk(KERN_ERR "lines_init - kstrdup returned NULL\n");
709
710                 if (parse_chan_pair(line->init_str, line, i, opts, &error)) {
711                         printk(KERN_ERR "parse_chan_pair failed for "
712                                "device %d : %s\n", i, error);
713                         line->valid = 0;
714                 }
715         }
716 }
717
718 struct winch {
719         struct list_head list;
720         int fd;
721         int tty_fd;
722         int pid;
723         struct tty_struct *tty;
724         unsigned long stack;
725 };
726
727 static void free_winch(struct winch *winch, int free_irq_ok)
728 {
729         list_del(&winch->list);
730
731         if (winch->pid != -1)
732                 os_kill_process(winch->pid, 1);
733         if (winch->fd != -1)
734                 os_close_file(winch->fd);
735         if (winch->stack != 0)
736                 free_stack(winch->stack, 0);
737         if (free_irq_ok)
738                 free_irq(WINCH_IRQ, winch);
739         kfree(winch);
740 }
741
742 static irqreturn_t winch_interrupt(int irq, void *data)
743 {
744         struct winch *winch = data;
745         struct tty_struct *tty;
746         struct line *line;
747         int err;
748         char c;
749
750         if (winch->fd != -1) {
751                 err = generic_read(winch->fd, &c, NULL);
752                 if (err < 0) {
753                         if (err != -EAGAIN) {
754                                 printk(KERN_ERR "winch_interrupt : "
755                                        "read failed, errno = %d\n", -err);
756                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
757                                        "support\n", winch->tty_fd);
758                                 free_winch(winch, 0);
759                                 return IRQ_HANDLED;
760                         }
761                         goto out;
762                 }
763         }
764         tty = winch->tty;
765         if (tty != NULL) {
766                 line = tty->driver_data;
767                 if (line != NULL) {
768                         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
769                                          &tty->winsize.ws_col);
770                         kill_pgrp(tty->pgrp, SIGWINCH, 1);
771                 }
772         }
773  out:
774         if (winch->fd != -1)
775                 reactivate_fd(winch->fd, WINCH_IRQ);
776         return IRQ_HANDLED;
777 }
778
779 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
780                         unsigned long stack)
781 {
782         struct winch *winch;
783
784         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
785         if (winch == NULL) {
786                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
787                 goto cleanup;
788         }
789
790         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
791                                    .fd          = fd,
792                                    .tty_fd      = tty_fd,
793                                    .pid         = pid,
794                                    .tty         = tty,
795                                    .stack       = stack });
796
797         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
798                            IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
799                            "winch", winch) < 0) {
800                 printk(KERN_ERR "register_winch_irq - failed to register "
801                        "IRQ\n");
802                 goto out_free;
803         }
804
805         spin_lock(&winch_handler_lock);
806         list_add(&winch->list, &winch_handlers);
807         spin_unlock(&winch_handler_lock);
808
809         return;
810
811  out_free:
812         kfree(winch);
813  cleanup:
814         os_kill_process(pid, 1);
815         os_close_file(fd);
816         if (stack != 0)
817                 free_stack(stack, 0);
818 }
819
820 static void unregister_winch(struct tty_struct *tty)
821 {
822         struct list_head *ele;
823         struct winch *winch;
824
825         spin_lock(&winch_handler_lock);
826
827         list_for_each(ele, &winch_handlers) {
828                 winch = list_entry(ele, struct winch, list);
829                 if (winch->tty == tty) {
830                         free_winch(winch, 1);
831                         break;
832                 }
833         }
834         spin_unlock(&winch_handler_lock);
835 }
836
837 static void winch_cleanup(void)
838 {
839         struct list_head *ele, *next;
840         struct winch *winch;
841
842         spin_lock(&winch_handler_lock);
843
844         list_for_each_safe(ele, next, &winch_handlers) {
845                 winch = list_entry(ele, struct winch, list);
846                 free_winch(winch, 1);
847         }
848
849         spin_unlock(&winch_handler_lock);
850 }
851 __uml_exitcall(winch_cleanup);
852
853 char *add_xterm_umid(char *base)
854 {
855         char *umid, *title;
856         int len;
857
858         umid = get_umid();
859         if (*umid == '\0')
860                 return base;
861
862         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
863         title = kmalloc(len, GFP_KERNEL);
864         if (title == NULL) {
865                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
866                 return base;
867         }
868
869         snprintf(title, len, "%s (%s)", base, umid);
870         return title;
871 }