[PATCH] uml: hot-unplug code cleanup
[linux-2.6.git] / arch / um / drivers / line.c
1 /* 
2  * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
3  * Licensed under the GPL
4  */
5
6 #include "linux/sched.h"
7 #include "linux/slab.h"
8 #include "linux/list.h"
9 #include "linux/kd.h"
10 #include "linux/interrupt.h"
11 #include "linux/devfs_fs_kernel.h"
12 #include "asm/uaccess.h"
13 #include "chan_kern.h"
14 #include "irq_user.h"
15 #include "line.h"
16 #include "kern.h"
17 #include "user_util.h"
18 #include "kern_util.h"
19 #include "os.h"
20 #include "irq_kern.h"
21
22 #define LINE_BUFSIZE 4096
23
24 static irqreturn_t line_interrupt(int irq, void *data, struct pt_regs *unused)
25 {
26         struct tty_struct *tty = data;
27         struct line *line = tty->driver_data;
28
29         if (line)
30                 chan_interrupt(&line->chan_list, &line->task, tty, irq);
31         return IRQ_HANDLED;
32 }
33
34 static void line_timer_cb(void *arg)
35 {
36         struct tty_struct *tty = arg;
37         struct line *line = tty->driver_data;
38
39         line_interrupt(line->driver->read_irq, arg, NULL);
40 }
41
42 /* Returns the free space inside the ring buffer of this line.
43  *
44  * Should be called while holding line->lock (this does not modify datas).
45  */
46 static int write_room(struct line *line)
47 {
48         int n;
49
50         if (line->buffer == NULL)
51                 return LINE_BUFSIZE - 1;
52
53         /* This is for the case where the buffer is wrapped! */
54         n = line->head - line->tail;
55
56         if (n <= 0)
57                 n = LINE_BUFSIZE + n; /* The other case */
58         return n - 1;
59 }
60
61 int line_write_room(struct tty_struct *tty)
62 {
63         struct line *line = tty->driver_data;
64         unsigned long flags;
65         int room;
66
67         if (tty->stopped)
68                 return 0;
69
70         spin_lock_irqsave(&line->lock, flags);
71         room = write_room(line);
72         spin_unlock_irqrestore(&line->lock, flags);
73
74         /*XXX: Warning to remove */
75         if (0 == room)
76                 printk(KERN_DEBUG "%s: %s: no room left in buffer\n",
77                        __FUNCTION__,tty->name);
78         return room;
79 }
80
81 int line_chars_in_buffer(struct tty_struct *tty)
82 {
83         struct line *line = tty->driver_data;
84         unsigned long flags;
85         int ret;
86
87         spin_lock_irqsave(&line->lock, flags);
88
89         /*write_room subtracts 1 for the needed NULL, so we readd it.*/
90         ret = LINE_BUFSIZE - (write_room(line) + 1);
91         spin_unlock_irqrestore(&line->lock, flags);
92
93         return ret;
94 }
95
96 /*
97  * This copies the content of buf into the circular buffer associated with
98  * this line.
99  * The return value is the number of characters actually copied, i.e. the ones
100  * for which there was space: this function is not supposed to ever flush out
101  * the circular buffer.
102  *
103  * Must be called while holding line->lock!
104  */
105 static int buffer_data(struct line *line, const char *buf, int len)
106 {
107         int end, room;
108
109         if(line->buffer == NULL){
110                 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
111                 if (line->buffer == NULL) {
112                         printk("buffer_data - atomic allocation failed\n");
113                         return(0);
114                 }
115                 line->head = line->buffer;
116                 line->tail = line->buffer;
117         }
118
119         room = write_room(line);
120         len = (len > room) ? room : len;
121
122         end = line->buffer + LINE_BUFSIZE - line->tail;
123
124         if (len < end){
125                 memcpy(line->tail, buf, len);
126                 line->tail += len;
127         } else {
128                 /* The circular buffer is wrapping */
129                 memcpy(line->tail, buf, end);
130                 buf += end;
131                 memcpy(line->buffer, buf, len - end);
132                 line->tail = line->buffer + len - end;
133         }
134
135         return len;
136 }
137
138 /*
139  * Flushes the ring buffer to the output channels. That is, write_chan is
140  * called, passing it line->head as buffer, and an appropriate count.
141  *
142  * On exit, returns 1 when the buffer is empty,
143  * 0 when the buffer is not empty on exit,
144  * and -errno when an error occurred.
145  *
146  * Must be called while holding line->lock!*/
147 static int flush_buffer(struct line *line)
148 {
149         int n, count;
150
151         if ((line->buffer == NULL) || (line->head == line->tail))
152                 return 1;
153
154         if (line->tail < line->head) {
155                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
156                 count = line->buffer + LINE_BUFSIZE - line->head;
157
158                 n = write_chan(&line->chan_list, line->head, count,
159                                line->driver->write_irq);
160                 if (n < 0)
161                         return n;
162                 if (n == count) {
163                         /* We have flushed from ->head to buffer end, now we
164                          * must flush only from the beginning to ->tail.*/
165                         line->head = line->buffer;
166                 } else {
167                         line->head += n;
168                         return 0;
169                 }
170         }
171
172         count = line->tail - line->head;
173         n = write_chan(&line->chan_list, line->head, count, 
174                        line->driver->write_irq);
175
176         if(n < 0)
177                 return n;
178
179         line->head += n;
180         return line->head == line->tail;
181 }
182
183 void line_flush_buffer(struct tty_struct *tty)
184 {
185         struct line *line = tty->driver_data;
186         unsigned long flags;
187         int err;
188
189         /*XXX: copied from line_write, verify if it is correct!*/
190         if(tty->stopped)
191                 return;
192                 //return 0;
193
194         spin_lock_irqsave(&line->lock, flags);
195         err = flush_buffer(line);
196         /*if (err == 1)
197                 err = 0;*/
198         spin_unlock_irqrestore(&line->lock, flags);
199         //return err;
200 }
201
202 /* We map both ->flush_chars and ->put_char (which go in pair) onto ->flush_buffer
203  * and ->write. Hope it's not that bad.*/
204 void line_flush_chars(struct tty_struct *tty)
205 {
206         line_flush_buffer(tty);
207 }
208
209 void line_put_char(struct tty_struct *tty, unsigned char ch)
210 {
211         line_write(tty, &ch, sizeof(ch));
212 }
213
214 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
215 {
216         struct line *line = tty->driver_data;
217         unsigned long flags;
218         int n, err, ret = 0;
219
220         if(tty->stopped)
221                 return 0;
222
223         spin_lock_irqsave(&line->lock, flags);
224         if (line->head != line->tail) {
225                 ret = buffer_data(line, buf, len);
226                 err = flush_buffer(line);
227                 if (err <= 0 && (err != -EAGAIN || !ret))
228                         ret = err;
229         } else {
230                 n = write_chan(&line->chan_list, buf, len, 
231                                line->driver->write_irq);
232                 if (n < 0) {
233                         ret = n;
234                         goto out_up;
235                 }
236
237                 len -= n;
238                 ret += n;
239                 if (len > 0)
240                         ret += buffer_data(line, buf + n, len);
241         }
242 out_up:
243         spin_unlock_irqrestore(&line->lock, flags);
244         return ret;
245 }
246
247 void line_set_termios(struct tty_struct *tty, struct termios * old)
248 {
249         /* nothing */
250 }
251
252 static struct {
253         int  cmd;
254         char *level;
255         char *name;
256 } tty_ioctls[] = {
257         /* don't print these, they flood the log ... */
258         { TCGETS,      NULL,       "TCGETS"      },
259         { TCSETS,      NULL,       "TCSETS"      },
260         { TCSETSW,     NULL,       "TCSETSW"     },
261         { TCFLSH,      NULL,       "TCFLSH"      },
262         { TCSBRK,      NULL,       "TCSBRK"      },
263
264         /* general tty stuff */
265         { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
266         { TCGETA,      KERN_DEBUG, "TCGETA"      },
267         { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
268         { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
269         { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
270
271         /* linux-specific ones */
272         { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
273         { KDGKBMODE,   KERN_INFO,  "KDGKBMODE"   },
274         { KDGKBTYPE,   KERN_INFO,  "KDGKBTYPE"   },
275         { KDSIGACCEPT, KERN_INFO,  "KDSIGACCEPT" },
276 };
277
278 int line_ioctl(struct tty_struct *tty, struct file * file,
279                unsigned int cmd, unsigned long arg)
280 {
281         int ret;
282         int i;
283
284         ret = 0;
285         switch(cmd) {
286 #ifdef TIOCGETP
287         case TIOCGETP:
288         case TIOCSETP:
289         case TIOCSETN:
290 #endif
291 #ifdef TIOCGETC
292         case TIOCGETC:
293         case TIOCSETC:
294 #endif
295 #ifdef TIOCGLTC
296         case TIOCGLTC:
297         case TIOCSLTC:
298 #endif
299         case TCGETS:
300         case TCSETSF:
301         case TCSETSW:
302         case TCSETS:
303         case TCGETA:
304         case TCSETAF:
305         case TCSETAW:
306         case TCSETA:
307         case TCXONC:
308         case TCFLSH:
309         case TIOCOUTQ:
310         case TIOCINQ:
311         case TIOCGLCKTRMIOS:
312         case TIOCSLCKTRMIOS:
313         case TIOCPKT:
314         case TIOCGSOFTCAR:
315         case TIOCSSOFTCAR:
316                 return -ENOIOCTLCMD;
317 #if 0
318         case TCwhatever:
319                 /* do something */
320                 break;
321 #endif
322         default:
323                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
324                         if (cmd == tty_ioctls[i].cmd)
325                                 break;
326                 if (i < ARRAY_SIZE(tty_ioctls)) {
327                         if (NULL != tty_ioctls[i].level)
328                                 printk("%s%s: %s: ioctl %s called\n",
329                                        tty_ioctls[i].level, __FUNCTION__,
330                                        tty->name, tty_ioctls[i].name);
331                 } else {
332                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
333                                __FUNCTION__, tty->name, cmd);
334                 }
335                 ret = -ENOIOCTLCMD;
336                 break;
337         }
338         return ret;
339 }
340
341 static irqreturn_t line_write_interrupt(int irq, void *data,
342                                         struct pt_regs *unused)
343 {
344         struct tty_struct *tty = data;
345         struct line *line = tty->driver_data;
346         int err;
347
348         /* Interrupts are enabled here because we registered the interrupt with
349          * SA_INTERRUPT (see line_setup_irq).*/
350
351         spin_lock_irq(&line->lock);
352         err = flush_buffer(line);
353         if (err == 0) {
354                 return IRQ_NONE;
355         } else if(err < 0) {
356                 line->head = line->buffer;
357                 line->tail = line->buffer;
358         }
359         spin_unlock_irq(&line->lock);
360
361         if(tty == NULL)
362                 return IRQ_NONE;
363
364         if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
365            (tty->ldisc.write_wakeup != NULL))
366                 (tty->ldisc.write_wakeup)(tty);
367         
368         /* BLOCKING mode
369          * In blocking mode, everything sleeps on tty->write_wait.
370          * Sleeping in the console driver would break non-blocking
371          * writes.
372          */
373
374         if (waitqueue_active(&tty->write_wait))
375                 wake_up_interruptible(&tty->write_wait);
376         return IRQ_HANDLED;
377 }
378
379 int line_setup_irq(int fd, int input, int output, struct tty_struct *tty)
380 {
381         struct line *line = tty->driver_data;
382         struct line_driver *driver = line->driver;
383         int err = 0, flags = SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM;
384
385         if (input)
386                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
387                                        line_interrupt, flags, 
388                                        driver->read_irq_name, tty);
389         if (err)
390                 return err;
391         if (output)
392                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
393                                         line_write_interrupt, flags, 
394                                         driver->write_irq_name, tty);
395         line->have_irq = 1;
396         return err;
397 }
398
399 void line_disable(struct tty_struct *tty, int current_irq)
400 {
401         struct line *line = tty->driver_data;
402
403         if(!line->have_irq)
404                 return;
405
406         if(line->driver->read_irq == current_irq)
407                 free_irq_later(line->driver->read_irq, tty);
408         else {
409                 free_irq(line->driver->read_irq, tty);
410         }
411
412         if(line->driver->write_irq == current_irq)
413                 free_irq_later(line->driver->write_irq, tty);
414         else {
415                 free_irq(line->driver->write_irq, tty);
416         }
417
418         line->have_irq = 0;
419 }
420
421 int line_open(struct line *lines, struct tty_struct *tty,
422               struct chan_opts *opts)
423 {
424         struct line *line;
425         int err = 0;
426
427         line = &lines[tty->index];
428         tty->driver_data = line;
429
430         /* The IRQ which takes this lock is not yet enabled and won't be run
431          * before the end, so we don't need to use spin_lock_irq.*/
432         spin_lock(&line->lock);
433         if (tty->count == 1) {
434                 if (!line->valid) {
435                         err = -ENODEV;
436                         goto out;
437                 }
438                 if (list_empty(&line->chan_list)) {
439                         err = parse_chan_pair(line->init_str, &line->chan_list,
440                                               line->init_pri, tty->index, opts);
441                         if(err) goto out;
442                         err = open_chan(&line->chan_list);
443                         if(err) goto out;
444                 }
445                 /* Here the interrupt is registered.*/
446                 enable_chan(&line->chan_list, tty);
447                 INIT_WORK(&line->task, line_timer_cb, tty);
448         }
449
450         if(!line->sigio){
451                 chan_enable_winch(&line->chan_list, tty);
452                 line->sigio = 1;
453         }
454         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
455                          &tty->winsize.ws_col);
456         line->count++;
457
458 out:
459         spin_unlock(&line->lock);
460         return err;
461 }
462
463 static void unregister_winch(struct tty_struct *tty);
464
465 void line_close(struct tty_struct *tty, struct file * filp)
466 {
467         struct line *line = tty->driver_data;
468
469         /* XXX: I assume this should be called in process context, not with
470          *  interrupts disabled!
471          */
472         spin_lock_irq(&line->lock);
473
474         /* We ignore the error anyway! */
475         flush_buffer(line);
476
477         line->count--;
478         if (tty->count == 1) {
479                 line_disable(tty, -1);
480                 tty->driver_data = NULL;
481         }
482
483         if((line->count == 0) && line->sigio){
484                 unregister_winch(tty);
485                 line->sigio = 0;
486         }
487
488         spin_unlock_irq(&line->lock);
489 }
490
491 void close_lines(struct line *lines, int nlines)
492 {
493         int i;
494
495         for(i = 0; i < nlines; i++)
496                 close_chan(&lines[i].chan_list);
497 }
498
499 /* Common setup code for both startup command line and mconsole initialization.
500  * @lines contains the the array (of size @num) to modify;
501  * @init is the setup string;
502  * @all_allowed is a boolean saying if we can setup the whole @lines
503  * at once. For instance, it will be usually true for startup init. (where we
504  * can use con=xterm) and false for mconsole.*/
505
506 int line_setup(struct line *lines, unsigned int num, char *init, int all_allowed)
507 {
508         int i, n;
509         char *end;
510
511         if(*init == '=') {
512                 /* We said con=/ssl= instead of con#=, so we are configuring all
513                  * consoles at once.*/
514                 n = -1;
515         } else {
516                 n = simple_strtoul(init, &end, 0);
517                 if(*end != '='){
518                         printk(KERN_ERR "line_setup failed to parse \"%s\"\n", 
519                                init);
520                         return 0;
521                 }
522                 init = end;
523         }
524         init++;
525
526         if (n >= (signed int) num) {
527                 printk("line_setup - %d out of range ((0 ... %d) allowed)\n",
528                        n, num - 1);
529                 return 0;
530         } else if (n >= 0){
531                 if (lines[n].count > 0) {
532                         printk("line_setup - device %d is open\n", n);
533                         return 0;
534                 }
535                 if (lines[n].init_pri <= INIT_ONE){
536                         lines[n].init_pri = INIT_ONE;
537                         if (!strcmp(init, "none"))
538                                 lines[n].valid = 0;
539                         else {
540                                 lines[n].init_str = init;
541                                 lines[n].valid = 1;
542                         }       
543                 }
544         } else if(!all_allowed){
545                 printk("line_setup - can't configure all devices from "
546                        "mconsole\n");
547                 return 0;
548         } else {
549                 for(i = 0; i < num; i++){
550                         if(lines[i].init_pri <= INIT_ALL){
551                                 lines[i].init_pri = INIT_ALL;
552                                 if(!strcmp(init, "none")) lines[i].valid = 0;
553                                 else {
554                                         lines[i].init_str = init;
555                                         lines[i].valid = 1;
556                                 }
557                         }
558                 }
559         }
560         return 1;
561 }
562
563 int line_config(struct line *lines, unsigned int num, char *str)
564 {
565         char *new = uml_strdup(str);
566
567         if(new == NULL){
568                 printk("line_config - uml_strdup failed\n");
569                 return -ENOMEM;
570         }
571         return !line_setup(lines, num, new, 0);
572 }
573
574 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
575                     int size, char **error_out)
576 {
577         struct line *line;
578         char *end;
579         int dev, n = 0;
580
581         dev = simple_strtoul(name, &end, 0);
582         if((*end != '\0') || (end == name)){
583                 *error_out = "line_get_config failed to parse device number";
584                 return 0;
585         }
586
587         if((dev < 0) || (dev >= num)){
588                 *error_out = "device number out of range";
589                 return 0;
590         }
591
592         line = &lines[dev];
593
594         spin_lock(&line->lock);
595         if(!line->valid)
596                 CONFIG_CHUNK(str, size, n, "none", 1);
597         else if(line->count == 0)
598                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
599         else n = chan_config_string(&line->chan_list, str, size, error_out);
600         spin_unlock(&line->lock);
601
602         return n;
603 }
604
605 int line_id(char **str, int *start_out, int *end_out)
606 {
607         char *end;
608         int n;
609
610         n = simple_strtoul(*str, &end, 0);
611         if((*end != '\0') || (end == *str))
612                 return -1;
613
614         *str = end;
615         *start_out = n;
616         *end_out = n;
617         return n;
618 }
619
620 int line_remove(struct line *lines, unsigned int num, int n)
621 {
622         char config[sizeof("conxxxx=none\0")];
623
624         sprintf(config, "%d=none", n);
625         return !line_setup(lines, num, config, 0);
626 }
627
628 struct tty_driver *line_register_devfs(struct lines *set,
629                          struct line_driver *line_driver, 
630                          struct tty_operations *ops, struct line *lines,
631                          int nlines)
632 {
633         int i;
634         struct tty_driver *driver = alloc_tty_driver(nlines);
635
636         if (!driver)
637                 return NULL;
638
639         driver->driver_name = line_driver->name;
640         driver->name = line_driver->device_name;
641         driver->devfs_name = line_driver->devfs_name;
642         driver->major = line_driver->major;
643         driver->minor_start = line_driver->minor_start;
644         driver->type = line_driver->type;
645         driver->subtype = line_driver->subtype;
646         driver->flags = TTY_DRIVER_REAL_RAW;
647         driver->init_termios = tty_std_termios;
648         tty_set_operations(driver, ops);
649
650         if (tty_register_driver(driver)) {
651                 printk("%s: can't register %s driver\n",
652                        __FUNCTION__,line_driver->name);
653                 put_tty_driver(driver);
654                 return NULL;
655         }
656
657         for(i = 0; i < nlines; i++){
658                 if(!lines[i].valid) 
659                         tty_unregister_device(driver, i);
660         }
661
662         mconsole_register_dev(&line_driver->mc);
663         return driver;
664 }
665
666 void lines_init(struct line *lines, int nlines)
667 {
668         struct line *line;
669         int i;
670
671         for(i = 0; i < nlines; i++){
672                 line = &lines[i];
673                 INIT_LIST_HEAD(&line->chan_list);
674                 spin_lock_init(&line->lock);
675                 if(line->init_str != NULL){
676                         line->init_str = uml_strdup(line->init_str);
677                         if(line->init_str == NULL)
678                                 printk("lines_init - uml_strdup returned "
679                                        "NULL\n");
680                 }
681         }
682 }
683
684 struct winch {
685         struct list_head list;
686         int fd;
687         int tty_fd;
688         int pid;
689         struct tty_struct *tty;
690 };
691
692 irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
693 {
694         struct winch *winch = data;
695         struct tty_struct *tty;
696         struct line *line;
697         int err;
698         char c;
699
700         if(winch->fd != -1){
701                 err = generic_read(winch->fd, &c, NULL);
702                 if(err < 0){
703                         if(err != -EAGAIN){
704                                 printk("winch_interrupt : read failed, "
705                                        "errno = %d\n", -err);
706                                 printk("fd %d is losing SIGWINCH support\n",
707                                        winch->tty_fd);
708                                 return IRQ_HANDLED;
709                         }
710                         goto out;
711                 }
712         }
713         tty  = winch->tty;
714         if (tty != NULL) {
715                 line = tty->driver_data;
716                 chan_window_size(&line->chan_list,
717                                  &tty->winsize.ws_row, 
718                                  &tty->winsize.ws_col);
719                 kill_pg(tty->pgrp, SIGWINCH, 1);
720         }
721  out:
722         if(winch->fd != -1)
723                 reactivate_fd(winch->fd, WINCH_IRQ);
724         return IRQ_HANDLED;
725 }
726
727 DECLARE_MUTEX(winch_handler_sem);
728 LIST_HEAD(winch_handlers);
729
730 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
731 {
732         struct winch *winch;
733
734         down(&winch_handler_sem);
735         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
736         if (winch == NULL) {
737                 printk("register_winch_irq - kmalloc failed\n");
738                 goto out;
739         }
740         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
741                                    .fd          = fd,
742                                    .tty_fd      = tty_fd,
743                                    .pid         = pid,
744                                    .tty         = tty });
745         list_add(&winch->list, &winch_handlers);
746         if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
747                           SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM, 
748                           "winch", winch) < 0)
749                 printk("register_winch_irq - failed to register IRQ\n");
750  out:
751         up(&winch_handler_sem);
752 }
753
754 static void unregister_winch(struct tty_struct *tty)
755 {
756         struct list_head *ele;
757         struct winch *winch, *found = NULL;
758
759         down(&winch_handler_sem);
760         list_for_each(ele, &winch_handlers){
761                 winch = list_entry(ele, struct winch, list);
762                 if(winch->tty == tty){
763                         found = winch;
764                         break;
765                 }
766         }
767
768         if(found == NULL)
769                 goto out;
770
771         if(winch->pid != -1)
772                 os_kill_process(winch->pid, 1);
773
774         free_irq(WINCH_IRQ, winch);
775         list_del(&winch->list);
776         kfree(winch);
777  out:
778         up(&winch_handler_sem);
779 }
780
781 static void winch_cleanup(void)
782 {
783         struct list_head *ele;
784         struct winch *winch;
785
786         list_for_each(ele, &winch_handlers){
787                 winch = list_entry(ele, struct winch, list);
788                 if(winch->fd != -1){
789                         deactivate_fd(winch->fd, WINCH_IRQ);
790                         os_close_file(winch->fd);
791                 }
792                 if(winch->pid != -1) 
793                         os_kill_process(winch->pid, 1);
794         }
795 }
796 __uml_exitcall(winch_cleanup);
797
798 char *add_xterm_umid(char *base)
799 {
800         char *umid, *title;
801         int len;
802
803         umid = get_umid(1);
804         if(umid == NULL)
805                 return base;
806         
807         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
808         title = kmalloc(len, GFP_KERNEL);
809         if(title == NULL){
810                 printk("Failed to allocate buffer for xterm title\n");
811                 return base;
812         }
813
814         snprintf(title, len, "%s (%s)", base, umid);
815         return title;
816 }