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[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 "os.h"
12
13 #define LINE_BUFSIZE 4096
14
15 static irqreturn_t line_interrupt(int irq, void *data)
16 {
17         struct chan *chan = data;
18         struct line *line = chan->line;
19         struct tty_struct *tty = line->tty;
20
21         if (line)
22                 chan_interrupt(&line->chan_list, &line->task, tty, irq);
23         return IRQ_HANDLED;
24 }
25
26 static void line_timer_cb(struct work_struct *work)
27 {
28         struct line *line = container_of(work, struct line, task.work);
29
30         if (!line->throttled)
31                 chan_interrupt(&line->chan_list, &line->task, line->tty,
32                                line->driver->read_irq);
33 }
34
35 /*
36  * Returns the free space inside the ring buffer of this line.
37  *
38  * Should be called while holding line->lock (this does not modify data).
39  */
40 static int write_room(struct line *line)
41 {
42         int n;
43
44         if (line->buffer == NULL)
45                 return LINE_BUFSIZE - 1;
46
47         /* This is for the case where the buffer is wrapped! */
48         n = line->head - line->tail;
49
50         if (n <= 0)
51                 n = LINE_BUFSIZE + n; /* The other case */
52         return n - 1;
53 }
54
55 int line_write_room(struct tty_struct *tty)
56 {
57         struct line *line = tty->driver_data;
58         unsigned long flags;
59         int room;
60
61         if (tty->stopped)
62                 return 0;
63
64         spin_lock_irqsave(&line->lock, flags);
65         room = write_room(line);
66         spin_unlock_irqrestore(&line->lock, flags);
67
68         /*XXX: Warning to remove */
69         if (0 == room)
70                 printk(KERN_DEBUG "%s: %s: no room left in buffer\n",
71                        __FUNCTION__,tty->name);
72         return room;
73 }
74
75 int line_chars_in_buffer(struct tty_struct *tty)
76 {
77         struct line *line = tty->driver_data;
78         unsigned long flags;
79         int ret;
80
81         spin_lock_irqsave(&line->lock, flags);
82
83         /*write_room subtracts 1 for the needed NULL, so we readd it.*/
84         ret = LINE_BUFSIZE - (write_room(line) + 1);
85         spin_unlock_irqrestore(&line->lock, flags);
86
87         return ret;
88 }
89
90 /*
91  * This copies the content of buf into the circular buffer associated with
92  * this line.
93  * The return value is the number of characters actually copied, i.e. the ones
94  * for which there was space: this function is not supposed to ever flush out
95  * the circular buffer.
96  *
97  * Must be called while holding line->lock!
98  */
99 static int buffer_data(struct line *line, const char *buf, int len)
100 {
101         int end, room;
102
103         if (line->buffer == NULL) {
104                 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
105                 if (line->buffer == NULL) {
106                         printk(KERN_ERR "buffer_data - atomic allocation "
107                                "failed\n");
108                         return 0;
109                 }
110                 line->head = line->buffer;
111                 line->tail = line->buffer;
112         }
113
114         room = write_room(line);
115         len = (len > room) ? room : len;
116
117         end = line->buffer + LINE_BUFSIZE - line->tail;
118
119         if (len < end) {
120                 memcpy(line->tail, buf, len);
121                 line->tail += len;
122         }
123         else {
124                 /* The circular buffer is wrapping */
125                 memcpy(line->tail, buf, end);
126                 buf += end;
127                 memcpy(line->buffer, buf, len - end);
128                 line->tail = line->buffer + len - end;
129         }
130
131         return len;
132 }
133
134 /*
135  * Flushes the ring buffer to the output channels. That is, write_chan is
136  * called, passing it line->head as buffer, and an appropriate count.
137  *
138  * On exit, returns 1 when the buffer is empty,
139  * 0 when the buffer is not empty on exit,
140  * and -errno when an error occurred.
141  *
142  * Must be called while holding line->lock!*/
143 static int flush_buffer(struct line *line)
144 {
145         int n, count;
146
147         if ((line->buffer == NULL) || (line->head == line->tail))
148                 return 1;
149
150         if (line->tail < line->head) {
151                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
152                 count = line->buffer + LINE_BUFSIZE - line->head;
153
154                 n = write_chan(&line->chan_list, line->head, count,
155                                line->driver->write_irq);
156                 if (n < 0)
157                         return n;
158                 if (n == count) {
159                         /*
160                          * We have flushed from ->head to buffer end, now we
161                          * must flush only from the beginning to ->tail.
162                          */
163                         line->head = line->buffer;
164                 } else {
165                         line->head += n;
166                         return 0;
167                 }
168         }
169
170         count = line->tail - line->head;
171         n = write_chan(&line->chan_list, line->head, count,
172                        line->driver->write_irq);
173
174         if (n < 0)
175                 return n;
176
177         line->head += n;
178         return line->head == line->tail;
179 }
180
181 void line_flush_buffer(struct tty_struct *tty)
182 {
183         struct line *line = tty->driver_data;
184         unsigned long flags;
185         int err;
186
187         /*XXX: copied from line_write, verify if it is correct!*/
188         if (tty->stopped)
189                 return;
190
191         spin_lock_irqsave(&line->lock, flags);
192         err = flush_buffer(line);
193         spin_unlock_irqrestore(&line->lock, flags);
194 }
195
196 /*
197  * We map both ->flush_chars and ->put_char (which go in pair) onto
198  * ->flush_buffer and ->write. Hope it's not that bad.
199  */
200 void line_flush_chars(struct tty_struct *tty)
201 {
202         line_flush_buffer(tty);
203 }
204
205 void line_put_char(struct tty_struct *tty, unsigned char ch)
206 {
207         line_write(tty, &ch, sizeof(ch));
208 }
209
210 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
211 {
212         struct line *line = tty->driver_data;
213         unsigned long flags;
214         int n, ret = 0;
215
216         if (tty->stopped)
217                 return 0;
218
219         spin_lock_irqsave(&line->lock, flags);
220         if (line->head != line->tail)
221                 ret = buffer_data(line, buf, len);
222         else {
223                 n = write_chan(&line->chan_list, buf, len,
224                                line->driver->write_irq);
225                 if (n < 0) {
226                         ret = n;
227                         goto out_up;
228                 }
229
230                 len -= n;
231                 ret += n;
232                 if (len > 0)
233                         ret += buffer_data(line, buf + n, len);
234         }
235 out_up:
236         spin_unlock_irqrestore(&line->lock, flags);
237         return ret;
238 }
239
240 void line_set_termios(struct tty_struct *tty, struct ktermios * old)
241 {
242         /* nothing */
243 }
244
245 static const struct {
246         int  cmd;
247         char *level;
248         char *name;
249 } tty_ioctls[] = {
250         /* don't print these, they flood the log ... */
251         { TCGETS,      NULL,       "TCGETS"      },
252         { TCSETS,      NULL,       "TCSETS"      },
253         { TCSETSW,     NULL,       "TCSETSW"     },
254         { TCFLSH,      NULL,       "TCFLSH"      },
255         { TCSBRK,      NULL,       "TCSBRK"      },
256
257         /* general tty stuff */
258         { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
259         { TCGETA,      KERN_DEBUG, "TCGETA"      },
260         { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
261         { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
262         { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
263
264         /* linux-specific ones */
265         { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
266         { KDGKBMODE,   KERN_INFO,  "KDGKBMODE"   },
267         { KDGKBTYPE,   KERN_INFO,  "KDGKBTYPE"   },
268         { KDSIGACCEPT, KERN_INFO,  "KDSIGACCEPT" },
269 };
270
271 int line_ioctl(struct tty_struct *tty, struct file * file,
272                unsigned int cmd, unsigned long arg)
273 {
274         int ret;
275         int i;
276
277         ret = 0;
278         switch(cmd) {
279 #ifdef TIOCGETP
280         case TIOCGETP:
281         case TIOCSETP:
282         case TIOCSETN:
283 #endif
284 #ifdef TIOCGETC
285         case TIOCGETC:
286         case TIOCSETC:
287 #endif
288 #ifdef TIOCGLTC
289         case TIOCGLTC:
290         case TIOCSLTC:
291 #endif
292         case TCGETS:
293         case TCSETSF:
294         case TCSETSW:
295         case TCSETS:
296         case TCGETA:
297         case TCSETAF:
298         case TCSETAW:
299         case TCSETA:
300         case TCXONC:
301         case TCFLSH:
302         case TIOCOUTQ:
303         case TIOCINQ:
304         case TIOCGLCKTRMIOS:
305         case TIOCSLCKTRMIOS:
306         case TIOCPKT:
307         case TIOCGSOFTCAR:
308         case TIOCSSOFTCAR:
309                 return -ENOIOCTLCMD;
310 #if 0
311         case TCwhatever:
312                 /* do something */
313                 break;
314 #endif
315         default:
316                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
317                         if (cmd == tty_ioctls[i].cmd)
318                                 break;
319                 if (i == ARRAY_SIZE(tty_ioctls)) {
320                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
321                                __FUNCTION__, tty->name, cmd);
322                 }
323                 ret = -ENOIOCTLCMD;
324                 break;
325         }
326         return ret;
327 }
328
329 void line_throttle(struct tty_struct *tty)
330 {
331         struct line *line = tty->driver_data;
332
333         deactivate_chan(&line->chan_list, line->driver->read_irq);
334         line->throttled = 1;
335 }
336
337 void line_unthrottle(struct tty_struct *tty)
338 {
339         struct line *line = tty->driver_data;
340
341         line->throttled = 0;
342         chan_interrupt(&line->chan_list, &line->task, tty,
343                        line->driver->read_irq);
344
345         /*
346          * Maybe there is enough stuff pending that calling the interrupt
347          * throttles us again.  In this case, line->throttled will be 1
348          * again and we shouldn't turn the interrupt back on.
349          */
350         if (!line->throttled)
351                 reactivate_chan(&line->chan_list, line->driver->read_irq);
352 }
353
354 static irqreturn_t line_write_interrupt(int irq, void *data)
355 {
356         struct chan *chan = data;
357         struct line *line = chan->line;
358         struct tty_struct *tty = line->tty;
359         int err;
360
361         /*
362          * Interrupts are disabled here because we registered the interrupt with
363          * IRQF_DISABLED (see line_setup_irq).
364          */
365
366         spin_lock(&line->lock);
367         err = flush_buffer(line);
368         if (err == 0) {
369                 return IRQ_NONE;
370         } else if (err < 0) {
371                 line->head = line->buffer;
372                 line->tail = line->buffer;
373         }
374         spin_unlock(&line->lock);
375
376         if (tty == NULL)
377                 return IRQ_NONE;
378
379         if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
380            (tty->ldisc.write_wakeup != NULL))
381                 (tty->ldisc.write_wakeup)(tty);
382
383         /*
384          * BLOCKING mode
385          * In blocking mode, everything sleeps on tty->write_wait.
386          * Sleeping in the console driver would break non-blocking
387          * writes.
388          */
389
390         if (waitqueue_active(&tty->write_wait))
391                 wake_up_interruptible(&tty->write_wait);
392         return IRQ_HANDLED;
393 }
394
395 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
396 {
397         const struct line_driver *driver = line->driver;
398         int err = 0, flags = IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM;
399
400         if (input)
401                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
402                                        line_interrupt, flags,
403                                        driver->read_irq_name, data);
404         if (err)
405                 return err;
406         if (output)
407                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
408                                         line_write_interrupt, flags,
409                                         driver->write_irq_name, data);
410         line->have_irq = 1;
411         return err;
412 }
413
414 /*
415  * Normally, a driver like this can rely mostly on the tty layer
416  * locking, particularly when it comes to the driver structure.
417  * However, in this case, mconsole requests can come in "from the
418  * side", and race with opens and closes.
419  *
420  * mconsole config requests will want to be sure the device isn't in
421  * use, and get_config, open, and close will want a stable
422  * configuration.  The checking and modification of the configuration
423  * is done under a spinlock.  Checking whether the device is in use is
424  * line->tty->count > 1, also under the spinlock.
425  *
426  * tty->count serves to decide whether the device should be enabled or
427  * disabled on the host.  If it's equal to 1, then we are doing the
428  * first open or last close.  Otherwise, open and close just return.
429  */
430
431 int line_open(struct line *lines, struct tty_struct *tty)
432 {
433         struct line *line = &lines[tty->index];
434         int err = -ENODEV;
435
436         spin_lock(&line->count_lock);
437         if (!line->valid)
438                 goto out_unlock;
439
440         err = 0;
441         if (tty->count > 1)
442                 goto out_unlock;
443
444         spin_unlock(&line->count_lock);
445
446         tty->driver_data = line;
447         line->tty = tty;
448
449         err = enable_chan(line);
450         if (err)
451                 return err;
452
453         INIT_DELAYED_WORK(&line->task, line_timer_cb);
454
455         if (!line->sigio) {
456                 chan_enable_winch(&line->chan_list, tty);
457                 line->sigio = 1;
458         }
459
460         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
461                          &tty->winsize.ws_col);
462
463         return err;
464
465 out_unlock:
466         spin_unlock(&line->count_lock);
467         return err;
468 }
469
470 static void unregister_winch(struct tty_struct *tty);
471
472 void line_close(struct tty_struct *tty, struct file * filp)
473 {
474         struct line *line = tty->driver_data;
475
476         /*
477          * If line_open fails (and tty->driver_data is never set),
478          * tty_open will call line_close.  So just return in this case.
479          */
480         if (line == NULL)
481                 return;
482
483         /* We ignore the error anyway! */
484         flush_buffer(line);
485
486         spin_lock(&line->count_lock);
487         if (!line->valid)
488                 goto out_unlock;
489
490         if (tty->count > 1)
491                 goto out_unlock;
492
493         spin_unlock(&line->count_lock);
494
495         line->tty = NULL;
496         tty->driver_data = NULL;
497
498         if (line->sigio) {
499                 unregister_winch(tty);
500                 line->sigio = 0;
501         }
502
503         return;
504
505 out_unlock:
506         spin_unlock(&line->count_lock);
507 }
508
509 void close_lines(struct line *lines, int nlines)
510 {
511         int i;
512
513         for(i = 0; i < nlines; i++)
514                 close_chan(&lines[i].chan_list, 0);
515 }
516
517 static int setup_one_line(struct line *lines, int n, char *init, int init_prio,
518                           char **error_out)
519 {
520         struct line *line = &lines[n];
521         int err = -EINVAL;
522
523         spin_lock(&line->count_lock);
524
525         if (line->tty != NULL) {
526                 *error_out = "Device is already open";
527                 goto out;
528         }
529
530         if (line->init_pri <= init_prio) {
531                 line->init_pri = init_prio;
532                 if (!strcmp(init, "none"))
533                         line->valid = 0;
534                 else {
535                         line->init_str = init;
536                         line->valid = 1;
537                 }
538         }
539         err = 0;
540 out:
541         spin_unlock(&line->count_lock);
542         return err;
543 }
544
545 /*
546  * Common setup code for both startup command line and mconsole initialization.
547  * @lines contains the array (of size @num) to modify;
548  * @init is the setup string;
549  * @error_out is an error string in the case of failure;
550  */
551
552 int line_setup(struct line *lines, unsigned int num, char *init,
553                char **error_out)
554 {
555         int i, n, err;
556         char *end;
557
558         if (*init == '=') {
559                 /*
560                  * We said con=/ssl= instead of con#=, so we are configuring all
561                  * consoles at once.
562                  */
563                 n = -1;
564         }
565         else {
566                 n = simple_strtoul(init, &end, 0);
567                 if (*end != '=') {
568                         *error_out = "Couldn't parse device number";
569                         return -EINVAL;
570                 }
571                 init = end;
572         }
573         init++;
574
575         if (n >= (signed int) num) {
576                 *error_out = "Device number out of range";
577                 return -EINVAL;
578         }
579         else if (n >= 0) {
580                 err = setup_one_line(lines, n, init, INIT_ONE, error_out);
581                 if (err)
582                         return err;
583         }
584         else {
585                 for(i = 0; i < num; i++) {
586                         err = setup_one_line(lines, i, init, INIT_ALL,
587                                              error_out);
588                         if (err)
589                                 return err;
590                 }
591         }
592         return n == -1 ? num : n;
593 }
594
595 int line_config(struct line *lines, unsigned int num, char *str,
596                 const struct chan_opts *opts, char **error_out)
597 {
598         struct line *line;
599         char *new;
600         int n;
601
602         if (*str == '=') {
603                 *error_out = "Can't configure all devices from mconsole";
604                 return -EINVAL;
605         }
606
607         new = kstrdup(str, GFP_KERNEL);
608         if (new == NULL) {
609                 *error_out = "Failed to allocate memory";
610                 return -ENOMEM;
611         }
612         n = line_setup(lines, num, new, error_out);
613         if (n < 0)
614                 return n;
615
616         line = &lines[n];
617         return parse_chan_pair(line->init_str, line, n, opts, error_out);
618 }
619
620 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
621                     int size, char **error_out)
622 {
623         struct line *line;
624         char *end;
625         int dev, n = 0;
626
627         dev = simple_strtoul(name, &end, 0);
628         if ((*end != '\0') || (end == name)) {
629                 *error_out = "line_get_config failed to parse device number";
630                 return 0;
631         }
632
633         if ((dev < 0) || (dev >= num)) {
634                 *error_out = "device number out of range";
635                 return 0;
636         }
637
638         line = &lines[dev];
639
640         spin_lock(&line->count_lock);
641         if (!line->valid)
642                 CONFIG_CHUNK(str, size, n, "none", 1);
643         else if (line->tty == NULL)
644                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
645         else n = chan_config_string(&line->chan_list, str, size, error_out);
646         spin_unlock(&line->count_lock);
647
648         return n;
649 }
650
651 int line_id(char **str, int *start_out, int *end_out)
652 {
653         char *end;
654         int n;
655
656         n = simple_strtoul(*str, &end, 0);
657         if ((*end != '\0') || (end == *str))
658                 return -1;
659
660         *str = end;
661         *start_out = n;
662         *end_out = n;
663         return n;
664 }
665
666 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
667 {
668         int err;
669         char config[sizeof("conxxxx=none\0")];
670
671         sprintf(config, "%d=none", n);
672         err = line_setup(lines, num, config, error_out);
673         if (err >= 0)
674                 err = 0;
675         return err;
676 }
677
678 struct tty_driver *register_lines(struct line_driver *line_driver,
679                                   const struct tty_operations *ops,
680                                   struct line *lines, int nlines)
681 {
682         int i;
683         struct tty_driver *driver = alloc_tty_driver(nlines);
684
685         if (!driver)
686                 return NULL;
687
688         driver->driver_name = line_driver->name;
689         driver->name = line_driver->device_name;
690         driver->major = line_driver->major;
691         driver->minor_start = line_driver->minor_start;
692         driver->type = line_driver->type;
693         driver->subtype = line_driver->subtype;
694         driver->flags = TTY_DRIVER_REAL_RAW;
695         driver->init_termios = tty_std_termios;
696         tty_set_operations(driver, ops);
697
698         if (tty_register_driver(driver)) {
699                 printk(KERN_ERR "register_lines : can't register %s driver\n",
700                        line_driver->name);
701                 put_tty_driver(driver);
702                 return NULL;
703         }
704
705         for(i = 0; i < nlines; i++) {
706                 if (!lines[i].valid)
707                         tty_unregister_device(driver, i);
708         }
709
710         mconsole_register_dev(&line_driver->mc);
711         return driver;
712 }
713
714 static DEFINE_SPINLOCK(winch_handler_lock);
715 static LIST_HEAD(winch_handlers);
716
717 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
718 {
719         struct line *line;
720         char *error;
721         int i;
722
723         for(i = 0; i < nlines; i++) {
724                 line = &lines[i];
725                 INIT_LIST_HEAD(&line->chan_list);
726
727                 if (line->init_str == NULL)
728                         continue;
729
730                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
731                 if (line->init_str == NULL)
732                         printk(KERN_ERR "lines_init - kstrdup returned NULL\n");
733
734                 if (parse_chan_pair(line->init_str, line, i, opts, &error)) {
735                         printk(KERN_ERR "parse_chan_pair failed for "
736                                "device %d : %s\n", i, error);
737                         line->valid = 0;
738                 }
739         }
740 }
741
742 struct winch {
743         struct list_head list;
744         int fd;
745         int tty_fd;
746         int pid;
747         struct tty_struct *tty;
748         unsigned long stack;
749 };
750
751 static void free_winch(struct winch *winch, int free_irq_ok)
752 {
753         list_del(&winch->list);
754
755         if (winch->pid != -1)
756                 os_kill_process(winch->pid, 1);
757         if (winch->fd != -1)
758                 os_close_file(winch->fd);
759         if (winch->stack != 0)
760                 free_stack(winch->stack, 0);
761         if (free_irq_ok)
762                 free_irq(WINCH_IRQ, winch);
763         kfree(winch);
764 }
765
766 static irqreturn_t winch_interrupt(int irq, void *data)
767 {
768         struct winch *winch = data;
769         struct tty_struct *tty;
770         struct line *line;
771         int err;
772         char c;
773
774         if (winch->fd != -1) {
775                 err = generic_read(winch->fd, &c, NULL);
776                 if (err < 0) {
777                         if (err != -EAGAIN) {
778                                 printk(KERN_ERR "winch_interrupt : "
779                                        "read failed, errno = %d\n", -err);
780                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
781                                        "support\n", winch->tty_fd);
782                                 free_winch(winch, 0);
783                                 return IRQ_HANDLED;
784                         }
785                         goto out;
786                 }
787         }
788         tty = winch->tty;
789         if (tty != NULL) {
790                 line = tty->driver_data;
791                 chan_window_size(&line->chan_list, &tty->winsize.ws_row,
792                                  &tty->winsize.ws_col);
793                 kill_pgrp(tty->pgrp, SIGWINCH, 1);
794         }
795  out:
796         if (winch->fd != -1)
797                 reactivate_fd(winch->fd, WINCH_IRQ);
798         return IRQ_HANDLED;
799 }
800
801 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
802                         unsigned long stack)
803 {
804         struct winch *winch;
805
806         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
807         if (winch == NULL) {
808                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
809                 goto cleanup;
810         }
811
812         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
813                                    .fd          = fd,
814                                    .tty_fd      = tty_fd,
815                                    .pid         = pid,
816                                    .tty         = tty,
817                                    .stack       = stack });
818
819         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
820                            IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
821                            "winch", winch) < 0) {
822                 printk(KERN_ERR "register_winch_irq - failed to register "
823                        "IRQ\n");
824                 goto out_free;
825         }
826
827         spin_lock(&winch_handler_lock);
828         list_add(&winch->list, &winch_handlers);
829         spin_unlock(&winch_handler_lock);
830
831         return;
832
833  out_free:
834         kfree(winch);
835  cleanup:
836         os_kill_process(pid, 1);
837         os_close_file(fd);
838         if (stack != 0)
839                 free_stack(stack, 0);
840 }
841
842 static void unregister_winch(struct tty_struct *tty)
843 {
844         struct list_head *ele;
845         struct winch *winch;
846
847         spin_lock(&winch_handler_lock);
848
849         list_for_each(ele, &winch_handlers) {
850                 winch = list_entry(ele, struct winch, list);
851                 if (winch->tty == tty) {
852                         free_winch(winch, 1);
853                         break;
854                 }
855         }
856         spin_unlock(&winch_handler_lock);
857 }
858
859 static void winch_cleanup(void)
860 {
861         struct list_head *ele, *next;
862         struct winch *winch;
863
864         spin_lock(&winch_handler_lock);
865
866         list_for_each_safe(ele, next, &winch_handlers) {
867                 winch = list_entry(ele, struct winch, list);
868                 free_winch(winch, 1);
869         }
870
871         spin_unlock(&winch_handler_lock);
872 }
873 __uml_exitcall(winch_cleanup);
874
875 char *add_xterm_umid(char *base)
876 {
877         char *umid, *title;
878         int len;
879
880         umid = get_umid();
881         if (*umid == '\0')
882                 return base;
883
884         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
885         title = kmalloc(len, GFP_KERNEL);
886         if (title == NULL) {
887                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
888                 return base;
889         }
890
891         snprintf(title, len, "%s (%s)", base, umid);
892         return title;
893 }