SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 chan *chan = data;
  27         struct line *line = chan->line;
  28         struct tty_struct *tty = line->tty;
  29
  30         if (line)
  31                 chan_interrupt(&line->chan_list, &line->task, tty, irq);
  32         return IRQ_HANDLED;
  33 }
  34
  35 static void line_timer_cb(void *arg)
  36 {
  37         struct line *line = arg;
  38
  39         chan_interrupt(&line->chan_list, &line->task, line->tty,
  40                        line->driver->read_irq);
  41 }
  42
  43 /* Returns the free space inside the ring buffer of this line.
  44  *
  45  * Should be called while holding line->lock (this does not modify datas).
  46  */
  47 static int write_room(struct line *line)
  48 {
  49         int n;
  50
  51         if (line->buffer == NULL)
  52                 return LINE_BUFSIZE - 1;
  53
  54         /* This is for the case where the buffer is wrapped! */
  55         n = line->head - line->tail;
  56
  57         if (n <= 0)
  58                 n = LINE_BUFSIZE + n; /* The other case */
  59         return n - 1;
  60 }
  61
  62 int line_write_room(struct tty_struct *tty)
  63 {
  64         struct line *line = tty->driver_data;
  65         unsigned long flags;
  66         int room;
  67
  68         if (tty->stopped)
  69                 return 0;
  70
  71         spin_lock_irqsave(&line->lock, flags);
  72         room = write_room(line);
  73         spin_unlock_irqrestore(&line->lock, flags);
  74
  75         /*XXX: Warning to remove */
  76         if (0 == room)
  77                 printk(KERN_DEBUG "%s: %s: no room left in buffer\n",
  78                        __FUNCTION__,tty->name);
  79         return room;
  80 }
  81
  82 int line_chars_in_buffer(struct tty_struct *tty)
  83 {
  84         struct line *line = tty->driver_data;
  85         unsigned long flags;
  86         int ret;
  87
  88         spin_lock_irqsave(&line->lock, flags);
  89
  90         /*write_room subtracts 1 for the needed NULL, so we readd it.*/
  91         ret = LINE_BUFSIZE - (write_room(line) + 1);
  92         spin_unlock_irqrestore(&line->lock, flags);
  93
  94         return ret;
  95 }
  96
  97 /*
  98  * This copies the content of buf into the circular buffer associated with
  99  * this line.
 100  * The return value is the number of characters actually copied, i.e. the ones
 101  * for which there was space: this function is not supposed to ever flush out
 102  * the circular buffer.
 103  *
 104  * Must be called while holding line->lock!
 105  */
 106 static int buffer_data(struct line *line, const char *buf, int len)
 107 {
 108         int end, room;
 109
 110         if(line->buffer == NULL){
 111                 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
 112                 if (line->buffer == NULL) {
 113                         printk("buffer_data - atomic allocation failed\n");
 114                         return(0);
 115                 }
 116                 line->head = line->buffer;
 117                 line->tail = line->buffer;
 118         }
 119
 120         room = write_room(line);
 121         len = (len > room) ? room : len;
 122
 123         end = line->buffer + LINE_BUFSIZE - line->tail;
 124
 125         if (len < end){
 126                 memcpy(line->tail, buf, len);
 127                 line->tail += len;
 128         }
 129         else {
 130                 /* The circular buffer is wrapping */
 131                 memcpy(line->tail, buf, end);
 132                 buf += end;
 133                 memcpy(line->buffer, buf, len - end);
 134                 line->tail = line->buffer + len - end;
 135         }
 136
 137         return len;
 138 }
 139
 140 /*
 141  * Flushes the ring buffer to the output channels. That is, write_chan is
 142  * called, passing it line->head as buffer, and an appropriate count.
 143  *
 144  * On exit, returns 1 when the buffer is empty,
 145  * 0 when the buffer is not empty on exit,
 146  * and -errno when an error occurred.
 147  *
 148  * Must be called while holding line->lock!*/
 149 static int flush_buffer(struct line *line)
 150 {
 151         int n, count;
 152
 153         if ((line->buffer == NULL) || (line->head == line->tail))
 154                 return 1;
 155
 156         if (line->tail < line->head) {
 157                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
 158                 count = line->buffer + LINE_BUFSIZE - line->head;
 159
 160                 n = write_chan(&line->chan_list, line->head, count,
 161                                line->driver->write_irq);
 162                 if (n < 0)
 163                         return n;
 164                 if (n == count) {
 165                         /* We have flushed from ->head to buffer end, now we
 166                          * must flush only from the beginning to ->tail.*/
 167                         line->head = line->buffer;
 168                 } else {
 169                         line->head += n;
 170                         return 0;
 171                 }
 172         }
 173
 174         count = line->tail - line->head;
 175         n = write_chan(&line->chan_list, line->head, count,
 176                        line->driver->write_irq);
 177
 178         if(n < 0)
 179                 return n;
 180
 181         line->head += n;
 182         return line->head == line->tail;
 183 }
 184
 185 void line_flush_buffer(struct tty_struct *tty)
 186 {
 187         struct line *line = tty->driver_data;
 188         unsigned long flags;
 189         int err;
 190
 191         /*XXX: copied from line_write, verify if it is correct!*/
 192         if(tty->stopped)
 193                 return;
 194                 //return 0;
 195
 196         spin_lock_irqsave(&line->lock, flags);
 197         err = flush_buffer(line);
 198         /*if (err == 1)
 199                 err = 0;*/
 200         spin_unlock_irqrestore(&line->lock, flags);
 201         //return err;
 202 }
 203
 204 /* We map both ->flush_chars and ->put_char (which go in pair) onto ->flush_buffer
 205  * and ->write. Hope it's not that bad.*/
 206 void line_flush_chars(struct tty_struct *tty)
 207 {
 208         line_flush_buffer(tty);
 209 }
 210
 211 void line_put_char(struct tty_struct *tty, unsigned char ch)
 212 {
 213         line_write(tty, &ch, sizeof(ch));
 214 }
 215
 216 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
 217 {
 218         struct line *line = tty->driver_data;
 219         unsigned long flags;
 220         int n, err, ret = 0;
 221
 222         if(tty->stopped)
 223                 return 0;
 224
 225         spin_lock_irqsave(&line->lock, flags);
 226         if (line->head != line->tail) {
 227                 ret = buffer_data(line, buf, len);
 228                 err = flush_buffer(line);
 229                 if (err <= 0 && (err != -EAGAIN || !ret))
 230                         ret = err;
 231         } else {
 232                 n = write_chan(&line->chan_list, buf, len,
 233                                line->driver->write_irq);
 234                 if (n < 0) {
 235                         ret = n;
 236                         goto out_up;
 237                 }
 238
 239                 len -= n;
 240                 ret += n;
 241                 if (len > 0)
 242                         ret += buffer_data(line, buf + n, len);
 243         }
 244 out_up:
 245         spin_unlock_irqrestore(&line->lock, flags);
 246         return ret;
 247 }
 248
 249 void line_set_termios(struct tty_struct *tty, struct termios * old)
 250 {
 251         /* nothing */
 252 }
 253
 254 static struct {
 255         int  cmd;
 256         char *level;
 257         char *name;
 258 } tty_ioctls[] = {
 259         /* don't print these, they flood the log ... */
 260         { TCGETS,      NULL,       "TCGETS"      },
 261         { TCSETS,      NULL,       "TCSETS"      },
 262         { TCSETSW,     NULL,       "TCSETSW"     },
 263         { TCFLSH,      NULL,       "TCFLSH"      },
 264         { TCSBRK,      NULL,       "TCSBRK"      },
 265
 266         /* general tty stuff */
 267         { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
 268         { TCGETA,      KERN_DEBUG, "TCGETA"      },
 269         { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
 270         { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
 271         { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
 272
 273         /* linux-specific ones */
 274         { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
 275         { KDGKBMODE,   KERN_INFO,  "KDGKBMODE"   },
 276         { KDGKBTYPE,   KERN_INFO,  "KDGKBTYPE"   },
 277         { KDSIGACCEPT, KERN_INFO,  "KDSIGACCEPT" },
 278 };
 279
 280 int line_ioctl(struct tty_struct *tty, struct file * file,
 281                unsigned int cmd, unsigned long arg)
 282 {
 283         int ret;
 284         int i;
 285
 286         ret = 0;
 287         switch(cmd) {
 288 #ifdef TIOCGETP
 289         case TIOCGETP:
 290         case TIOCSETP:
 291         case TIOCSETN:
 292 #endif
 293 #ifdef TIOCGETC
 294         case TIOCGETC:
 295         case TIOCSETC:
 296 #endif
 297 #ifdef TIOCGLTC
 298         case TIOCGLTC:
 299         case TIOCSLTC:
 300 #endif
 301         case TCGETS:
 302         case TCSETSF:
 303         case TCSETSW:
 304         case TCSETS:
 305         case TCGETA:
 306         case TCSETAF:
 307         case TCSETAW:
 308         case TCSETA:
 309         case TCXONC:
 310         case TCFLSH:
 311         case TIOCOUTQ:
 312         case TIOCINQ:
 313         case TIOCGLCKTRMIOS:
 314         case TIOCSLCKTRMIOS:
 315         case TIOCPKT:
 316         case TIOCGSOFTCAR:
 317         case TIOCSSOFTCAR:
 318                 return -ENOIOCTLCMD;
 319 #if 0
 320         case TCwhatever:
 321                 /* do something */
 322                 break;
 323 #endif
 324         default:
 325                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
 326                         if (cmd == tty_ioctls[i].cmd)
 327                                 break;
 328                 if (i < ARRAY_SIZE(tty_ioctls)) {
 329                         if (NULL != tty_ioctls[i].level)
 330                                 printk("%s%s: %s: ioctl %s called\n",
 331                                        tty_ioctls[i].level, __FUNCTION__,
 332                                        tty->name, tty_ioctls[i].name);
 333                 } else {
 334                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
 335                                __FUNCTION__, tty->name, cmd);
 336                 }
 337                 ret = -ENOIOCTLCMD;
 338                 break;
 339         }
 340         return ret;
 341 }
 342
 343 static irqreturn_t line_write_interrupt(int irq, void *data,
 344                                         struct pt_regs *unused)
 345 {
 346         struct chan *chan = data;
 347         struct line *line = chan->line;
 348         struct tty_struct *tty = line->tty;
 349         int err;
 350
 351         /* Interrupts are enabled here because we registered the interrupt with
 352          * SA_INTERRUPT (see line_setup_irq).*/
 353
 354         spin_lock_irq(&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_irq(&line->lock);
 363
 364         if(tty == NULL)
 365                 return IRQ_NONE;
 366
 367         if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
 368            (tty->ldisc.write_wakeup != NULL))
 369                 (tty->ldisc.write_wakeup)(tty);
 370
 371         /* BLOCKING mode
 372          * In blocking mode, everything sleeps on tty->write_wait.
 373          * Sleeping in the console driver would break non-blocking
 374          * writes.
 375          */
 376
 377         if (waitqueue_active(&tty->write_wait))
 378                 wake_up_interruptible(&tty->write_wait);
 379         return IRQ_HANDLED;
 380 }
 381
 382 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 383 {
 384         struct line_driver *driver = line->driver;
 385         int err = 0, flags = SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM;
 386
 387         if (input)
 388                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 389                                        line_interrupt, flags,
 390                                        driver->read_irq_name, data);
 391         if (err)
 392                 return err;
 393         if (output)
 394                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 395                                         line_write_interrupt, flags,
 396                                         driver->write_irq_name, data);
 397         line->have_irq = 1;
 398         return err;
 399 }
 400
 401 int line_open(struct line *lines, struct tty_struct *tty)
 402 {
 403         struct line *line;
 404         int err = -ENODEV;
 405
 406         line = &lines[tty->index];
 407         tty->driver_data = line;
 408
 409         /* The IRQ which takes this lock is not yet enabled and won't be run
 410          * before the end, so we don't need to use spin_lock_irq.*/
 411         spin_lock(&line->lock);
 412
 413         tty->driver_data = line;
 414         line->tty = tty;
 415         if(!line->valid)
 416                 goto out;
 417
 418         if(tty->count == 1){
 419                 /* Here the device is opened, if necessary, and interrupt
 420                  * is registered.
 421                  */
 422                 enable_chan(line);
 423                 INIT_WORK(&line->task, line_timer_cb, line);
 424
 425                 if(!line->sigio){
 426                         chan_enable_winch(&line->chan_list, tty);
 427                         line->sigio = 1;
 428                 }
 429
 430                 chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 431                                  &tty->winsize.ws_col);
 432         }
 433
 434         err = 0;
 435 out:
 436         spin_unlock(&line->lock);
 437         return err;
 438 }
 439
 440 static void unregister_winch(struct tty_struct *tty);
 441
 442 void line_close(struct tty_struct *tty, struct file * filp)
 443 {
 444         struct line *line = tty->driver_data;
 445
 446         /* XXX: I assume this should be called in process context, not with
 447          *  interrupts disabled!
 448          */
 449         spin_lock_irq(&line->lock);
 450
 451         /* We ignore the error anyway! */
 452         flush_buffer(line);
 453
 454         if(tty->count == 1){
 455                 line->tty = NULL;
 456                 tty->driver_data = NULL;
 457
 458                 if(line->sigio){
 459                         unregister_winch(tty);
 460                         line->sigio = 0;
 461                 }
 462         }
 463
 464         spin_unlock_irq(&line->lock);
 465 }
 466
 467 void close_lines(struct line *lines, int nlines)
 468 {
 469         int i;
 470
 471         for(i = 0; i < nlines; i++)
 472                 close_chan(&lines[i].chan_list, 0);
 473 }
 474
 475 /* Common setup code for both startup command line and mconsole initialization.
 476  * @lines contains the the array (of size @num) to modify;
 477  * @init is the setup string;
 478  */
 479
 480 int line_setup(struct line *lines, unsigned int num, char *init)
 481 {
 482         int i, n;
 483         char *end;
 484
 485         if(*init == '=') {
 486                 /* We said con=/ssl= instead of con#=, so we are configuring all
 487                  * consoles at once.*/
 488                 n = -1;
 489         }
 490         else {
 491                 n = simple_strtoul(init, &end, 0);
 492                 if(*end != '='){
 493                         printk(KERN_ERR "line_setup failed to parse \"%s\"\n",
 494                                init);
 495                         return 0;
 496                 }
 497                 init = end;
 498         }
 499         init++;
 500
 501         if (n >= (signed int) num) {
 502                 printk("line_setup - %d out of range ((0 ... %d) allowed)\n",
 503                        n, num - 1);
 504                 return 0;
 505         }
 506         else if (n >= 0){
 507                 if (lines[n].tty != NULL) {
 508                         printk("line_setup - device %d is open\n", n);
 509                         return 0;
 510                 }
 511                 if (lines[n].init_pri <= INIT_ONE){
 512                         lines[n].init_pri = INIT_ONE;
 513                         if (!strcmp(init, "none"))
 514                                 lines[n].valid = 0;
 515                         else {
 516                                 lines[n].init_str = init;
 517                                 lines[n].valid = 1;
 518                         }
 519                 }
 520         }
 521         else {
 522                 for(i = 0; i < num; i++){
 523                         if(lines[i].init_pri <= INIT_ALL){
 524                                 lines[i].init_pri = INIT_ALL;
 525                                 if(!strcmp(init, "none")) lines[i].valid = 0;
 526                                 else {
 527                                         lines[i].init_str = init;
 528                                         lines[i].valid = 1;
 529                                 }
 530                         }
 531                 }
 532         }
 533         return n == -1 ? num : n;
 534 }
 535
 536 int line_config(struct line *lines, unsigned int num, char *str,
 537                 struct chan_opts *opts)
 538 {
 539         struct line *line;
 540         char *new;
 541         int n;
 542
 543         if(*str == '='){
 544                 printk("line_config - can't configure all devices from "
 545                        "mconsole\n");
 546                 return 1;
 547         }
 548
 549         new = kstrdup(str, GFP_KERNEL);
 550         if(new == NULL){
 551                 printk("line_config - kstrdup failed\n");
 552                 return 1;
 553         }
 554         n = line_setup(lines, num, new);
 555         if(n < 0)
 556                 return 1;
 557
 558         line = &lines[n];
 559         return parse_chan_pair(line->init_str, line, n, opts);
 560 }
 561
 562 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 563                     int size, char **error_out)
 564 {
 565         struct line *line;
 566         char *end;
 567         int dev, n = 0;
 568
 569         dev = simple_strtoul(name, &end, 0);
 570         if((*end != '\0') || (end == name)){
 571                 *error_out = "line_get_config failed to parse device number";
 572                 return 0;
 573         }
 574
 575         if((dev < 0) || (dev >= num)){
 576                 *error_out = "device number out of range";
 577                 return 0;
 578         }
 579
 580         line = &lines[dev];
 581
 582         spin_lock(&line->lock);
 583         if(!line->valid)
 584                 CONFIG_CHUNK(str, size, n, "none", 1);
 585         else if(line->tty == NULL)
 586                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 587         else n = chan_config_string(&line->chan_list, str, size, error_out);
 588         spin_unlock(&line->lock);
 589
 590         return n;
 591 }
 592
 593 int line_id(char **str, int *start_out, int *end_out)
 594 {
 595         char *end;
 596         int n;
 597
 598         n = simple_strtoul(*str, &end, 0);
 599         if((*end != '\0') || (end == *str))
 600                 return -1;
 601
 602         *str = end;
 603         *start_out = n;
 604         *end_out = n;
 605         return n;
 606 }
 607
 608 int line_remove(struct line *lines, unsigned int num, int n)
 609 {
 610         int err;
 611         char config[sizeof("conxxxx=none\0")];
 612
 613         sprintf(config, "%d=none", n);
 614         err = line_setup(lines, num, config);
 615         if(err >= 0)
 616                 err = 0;
 617         return err;
 618 }
 619
 620 struct tty_driver *line_register_devfs(struct lines *set,
 621                          struct line_driver *line_driver,
 622                          struct tty_operations *ops, struct line *lines,
 623                          int nlines)
 624 {
 625         int i;
 626         struct tty_driver *driver = alloc_tty_driver(nlines);
 627
 628         if (!driver)
 629                 return NULL;
 630
 631         driver->driver_name = line_driver->name;
 632         driver->name = line_driver->device_name;
 633         driver->devfs_name = line_driver->devfs_name;
 634         driver->major = line_driver->major;
 635         driver->minor_start = line_driver->minor_start;
 636         driver->type = line_driver->type;
 637         driver->subtype = line_driver->subtype;
 638         driver->flags = TTY_DRIVER_REAL_RAW;
 639         driver->init_termios = tty_std_termios;
 640         tty_set_operations(driver, ops);
 641
 642         if (tty_register_driver(driver)) {
 643                 printk("%s: can't register %s driver\n",
 644                        __FUNCTION__,line_driver->name);
 645                 put_tty_driver(driver);
 646                 return NULL;
 647         }
 648
 649         for(i = 0; i < nlines; i++){
 650                 if(!lines[i].valid)
 651                         tty_unregister_device(driver, i);
 652         }
 653
 654         mconsole_register_dev(&line_driver->mc);
 655         return driver;
 656 }
 657
 658 static DEFINE_SPINLOCK(winch_handler_lock);
 659 static LIST_HEAD(winch_handlers);
 660
 661 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 662 {
 663         struct line *line;
 664         int i;
 665
 666         for(i = 0; i < nlines; i++){
 667                 line = &lines[i];
 668                 INIT_LIST_HEAD(&line->chan_list);
 669
 670                 if(line->init_str == NULL)
 671                         continue;
 672
 673                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
 674                 if(line->init_str == NULL)
 675                         printk("lines_init - kstrdup returned NULL\n");
 676
 677                 if(parse_chan_pair(line->init_str, line, i, opts)){
 678                         printk("parse_chan_pair failed for device %d\n", i);
 679                         line->valid = 0;
 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, &tty->winsize.ws_row,
 717                                  &tty->winsize.ws_col);
 718                 kill_pg(tty->pgrp, SIGWINCH, 1);
 719         }
 720  out:
 721         if(winch->fd != -1)
 722                 reactivate_fd(winch->fd, WINCH_IRQ);
 723         return IRQ_HANDLED;
 724 }
 725
 726 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
 727 {
 728         struct winch *winch;
 729
 730         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 731         if (winch == NULL) {
 732                 printk("register_winch_irq - kmalloc failed\n");
 733                 return;
 734         }
 735
 736         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 737                                    .fd          = fd,
 738                                    .tty_fd      = tty_fd,
 739                                    .pid         = pid,
 740                                    .tty         = tty });
 741
 742         spin_lock(&winch_handler_lock);
 743         list_add(&winch->list, &winch_handlers);
 744         spin_unlock(&winch_handler_lock);
 745
 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 }
 751
 752 static void unregister_winch(struct tty_struct *tty)
 753 {
 754         struct list_head *ele;
 755         struct winch *winch, *found = NULL;
 756
 757         spin_lock(&winch_handler_lock);
 758         list_for_each(ele, &winch_handlers){
 759                 winch = list_entry(ele, struct winch, list);
 760                 if(winch->tty == tty){
 761                         found = winch;
 762                         break;
 763                 }
 764         }
 765         if(found == NULL)
 766                 goto err;
 767
 768         list_del(&winch->list);
 769         spin_unlock(&winch_handler_lock);
 770
 771         if(winch->pid != -1)
 772                 os_kill_process(winch->pid, 1);
 773
 774         free_irq(WINCH_IRQ, winch);
 775         kfree(winch);
 776
 777         return;
 778 err:
 779         spin_unlock(&winch_handler_lock);
 780 }
 781
 782 /* XXX: No lock as it's an exitcall... is this valid? Depending on cleanup
 783  * order... are we sure that nothing else is done on the list? */
 784 static void winch_cleanup(void)
 785 {
 786         struct list_head *ele;
 787         struct winch *winch;
 788
 789         list_for_each(ele, &winch_handlers){
 790                 winch = list_entry(ele, struct winch, list);
 791                 if(winch->fd != -1){
 792                         /* Why is this different from the above free_irq(),
 793                          * which deactivates SIGIO? This searches the FD
 794                          * somewhere else and removes it from the list... */
 795                         deactivate_fd(winch->fd, WINCH_IRQ);
 796                         os_close_file(winch->fd);
 797                 }
 798                 if(winch->pid != -1)
 799                         os_kill_process(winch->pid, 1);
 800         }
 801 }
 802 __uml_exitcall(winch_cleanup);
 803
 804 char *add_xterm_umid(char *base)
 805 {
 806         char *umid, *title;
 807         int len;
 808
 809         umid = get_umid(1);
 810         if(umid == NULL)
 811                 return base;
 812
 813         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 814         title = kmalloc(len, GFP_KERNEL);
 815         if(title == NULL){
 816                 printk("Failed to allocate buffer for xterm title\n");
 817                 return base;
 818         }
 819
 820         snprintf(title, len, "%s (%s)", base, umid);
 821         return title;
 822 }