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 "linux/sched.h"
   9 #include "linux/slab.h"
  10 #include "chan_kern.h"
  11 #include "irq_kern.h"
  12 #include "irq_user.h"
  13 #include "kern_util.h"
  14 #include "os.h"
  15
  16 #define LINE_BUFSIZE 4096
  17
  18 static irqreturn_t line_interrupt(int irq, void *data)
  19 {
  20         struct chan *chan = data;
  21         struct line *line = chan->line;
  22
  23         if (line)
  24                 chan_interrupt(&line->chan_list, &line->task, line->tty, irq);
  25         return IRQ_HANDLED;
  26 }
  27
  28 static void line_timer_cb(struct work_struct *work)
  29 {
  30         struct line *line = container_of(work, struct line, task.work);
  31
  32         if (!line->throttled)
  33                 chan_interrupt(&line->chan_list, &line->task, line->tty,
  34                                line->driver->read_irq);
  35 }
  36
  37 /*
  38  * Returns the free space inside the ring buffer of this line.
  39  *
  40  * Should be called while holding line->lock (this does not modify data).
  41  */
  42 static int write_room(struct line *line)
  43 {
  44         int n;
  45
  46         if (line->buffer == NULL)
  47                 return LINE_BUFSIZE - 1;
  48
  49         /* This is for the case where the buffer is wrapped! */
  50         n = line->head - line->tail;
  51
  52         if (n <= 0)
  53                 n += LINE_BUFSIZE; /* The other case */
  54         return n - 1;
  55 }
  56
  57 int line_write_room(struct tty_struct *tty)
  58 {
  59         struct line *line = tty->driver_data;
  60         unsigned long flags;
  61         int room;
  62
  63         spin_lock_irqsave(&line->lock, flags);
  64         room = write_room(line);
  65         spin_unlock_irqrestore(&line->lock, flags);
  66
  67         return room;
  68 }
  69
  70 int line_chars_in_buffer(struct tty_struct *tty)
  71 {
  72         struct line *line = tty->driver_data;
  73         unsigned long flags;
  74         int ret;
  75
  76         spin_lock_irqsave(&line->lock, flags);
  77         /* write_room subtracts 1 for the needed NULL, so we readd it.*/
  78         ret = LINE_BUFSIZE - (write_room(line) + 1);
  79         spin_unlock_irqrestore(&line->lock, flags);
  80
  81         return ret;
  82 }
  83
  84 /*
  85  * This copies the content of buf into the circular buffer associated with
  86  * this line.
  87  * The return value is the number of characters actually copied, i.e. the ones
  88  * for which there was space: this function is not supposed to ever flush out
  89  * the circular buffer.
  90  *
  91  * Must be called while holding line->lock!
  92  */
  93 static int buffer_data(struct line *line, const char *buf, int len)
  94 {
  95         int end, room;
  96
  97         if (line->buffer == NULL) {
  98                 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
  99                 if (line->buffer == NULL) {
 100                         printk(KERN_ERR "buffer_data - atomic allocation "
 101                                "failed\n");
 102                         return 0;
 103                 }
 104                 line->head = line->buffer;
 105                 line->tail = line->buffer;
 106         }
 107
 108         room = write_room(line);
 109         len = (len > room) ? room : len;
 110
 111         end = line->buffer + LINE_BUFSIZE - line->tail;
 112
 113         if (len < end) {
 114                 memcpy(line->tail, buf, len);
 115                 line->tail += len;
 116         }
 117         else {
 118                 /* The circular buffer is wrapping */
 119                 memcpy(line->tail, buf, end);
 120                 buf += end;
 121                 memcpy(line->buffer, buf, len - end);
 122                 line->tail = line->buffer + len - end;
 123         }
 124
 125         return len;
 126 }
 127
 128 /*
 129  * Flushes the ring buffer to the output channels. That is, write_chan is
 130  * called, passing it line->head as buffer, and an appropriate count.
 131  *
 132  * On exit, returns 1 when the buffer is empty,
 133  * 0 when the buffer is not empty on exit,
 134  * and -errno when an error occurred.
 135  *
 136  * Must be called while holding line->lock!*/
 137 static int flush_buffer(struct line *line)
 138 {
 139         int n, count;
 140
 141         if ((line->buffer == NULL) || (line->head == line->tail))
 142                 return 1;
 143
 144         if (line->tail < line->head) {
 145                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
 146                 count = line->buffer + LINE_BUFSIZE - line->head;
 147
 148                 n = write_chan(&line->chan_list, line->head, count,
 149                                line->driver->write_irq);
 150                 if (n < 0)
 151                         return n;
 152                 if (n == count) {
 153                         /*
 154                          * We have flushed from ->head to buffer end, now we
 155                          * must flush only from the beginning to ->tail.
 156                          */
 157                         line->head = line->buffer;
 158                 } else {
 159                         line->head += n;
 160                         return 0;
 161                 }
 162         }
 163
 164         count = line->tail - line->head;
 165         n = write_chan(&line->chan_list, line->head, count,
 166                        line->driver->write_irq);
 167
 168         if (n < 0)
 169                 return n;
 170
 171         line->head += n;
 172         return line->head == line->tail;
 173 }
 174
 175 void line_flush_buffer(struct tty_struct *tty)
 176 {
 177         struct line *line = tty->driver_data;
 178         unsigned long flags;
 179         int err;
 180
 181         spin_lock_irqsave(&line->lock, flags);
 182         err = flush_buffer(line);
 183         spin_unlock_irqrestore(&line->lock, flags);
 184 }
 185
 186 /*
 187  * We map both ->flush_chars and ->put_char (which go in pair) onto
 188  * ->flush_buffer and ->write. Hope it's not that bad.
 189  */
 190 void line_flush_chars(struct tty_struct *tty)
 191 {
 192         line_flush_buffer(tty);
 193 }
 194
 195 int line_put_char(struct tty_struct *tty, unsigned char ch)
 196 {
 197         return line_write(tty, &ch, sizeof(ch));
 198 }
 199
 200 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
 201 {
 202         struct line *line = tty->driver_data;
 203         unsigned long flags;
 204         int n, ret = 0;
 205
 206         spin_lock_irqsave(&line->lock, flags);
 207         if (line->head != line->tail)
 208                 ret = buffer_data(line, buf, len);
 209         else {
 210                 n = write_chan(&line->chan_list, buf, len,
 211                                line->driver->write_irq);
 212                 if (n < 0) {
 213                         ret = n;
 214                         goto out_up;
 215                 }
 216
 217                 len -= n;
 218                 ret += n;
 219                 if (len > 0)
 220                         ret += buffer_data(line, buf + n, len);
 221         }
 222 out_up:
 223         spin_unlock_irqrestore(&line->lock, flags);
 224         return ret;
 225 }
 226
 227 void line_set_termios(struct tty_struct *tty, struct ktermios * old)
 228 {
 229         /* nothing */
 230 }
 231
 232 static const struct {
 233         int  cmd;
 234         char *level;
 235         char *name;
 236 } tty_ioctls[] = {
 237         /* don't print these, they flood the log ... */
 238         { TCGETS,      NULL,       "TCGETS"      },
 239         { TCSETS,      NULL,       "TCSETS"      },
 240         { TCSETSW,     NULL,       "TCSETSW"     },
 241         { TCFLSH,      NULL,       "TCFLSH"      },
 242         { TCSBRK,      NULL,       "TCSBRK"      },
 243
 244         /* general tty stuff */
 245         { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
 246         { TCGETA,      KERN_DEBUG, "TCGETA"      },
 247         { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
 248         { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
 249         { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
 250
 251         /* linux-specific ones */
 252         { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
 253         { KDGKBMODE,   KERN_INFO,  "KDGKBMODE"   },
 254         { KDGKBTYPE,   KERN_INFO,  "KDGKBTYPE"   },
 255         { KDSIGACCEPT, KERN_INFO,  "KDSIGACCEPT" },
 256 };
 257
 258 int line_ioctl(struct tty_struct *tty, struct file * file,
 259                unsigned int cmd, unsigned long arg)
 260 {
 261         int ret;
 262         int i;
 263
 264         ret = 0;
 265         switch(cmd) {
 266 #ifdef TIOCGETP
 267         case TIOCGETP:
 268         case TIOCSETP:
 269         case TIOCSETN:
 270 #endif
 271 #ifdef TIOCGETC
 272         case TIOCGETC:
 273         case TIOCSETC:
 274 #endif
 275 #ifdef TIOCGLTC
 276         case TIOCGLTC:
 277         case TIOCSLTC:
 278 #endif
 279         /* Note: these are out of date as we now have TCGETS2 etc but this
 280            whole lot should probably go away */
 281         case TCGETS:
 282         case TCSETSF:
 283         case TCSETSW:
 284         case TCSETS:
 285         case TCGETA:
 286         case TCSETAF:
 287         case TCSETAW:
 288         case TCSETA:
 289         case TCXONC:
 290         case TCFLSH:
 291         case TIOCOUTQ:
 292         case TIOCINQ:
 293         case TIOCGLCKTRMIOS:
 294         case TIOCSLCKTRMIOS:
 295         case TIOCPKT:
 296         case TIOCGSOFTCAR:
 297         case TIOCSSOFTCAR:
 298                 return -ENOIOCTLCMD;
 299 #if 0
 300         case TCwhatever:
 301                 /* do something */
 302                 break;
 303 #endif
 304         default:
 305                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
 306                         if (cmd == tty_ioctls[i].cmd)
 307                                 break;
 308                 if (i == ARRAY_SIZE(tty_ioctls)) {
 309                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
 310                                __func__, tty->name, cmd);
 311                 }
 312                 ret = -ENOIOCTLCMD;
 313                 break;
 314         }
 315         return ret;
 316 }
 317
 318 void line_throttle(struct tty_struct *tty)
 319 {
 320         struct line *line = tty->driver_data;
 321
 322         deactivate_chan(&line->chan_list, line->driver->read_irq);
 323         line->throttled = 1;
 324 }
 325
 326 void line_unthrottle(struct tty_struct *tty)
 327 {
 328         struct line *line = tty->driver_data;
 329
 330         line->throttled = 0;
 331         chan_interrupt(&line->chan_list, &line->task, tty,
 332                        line->driver->read_irq);
 333
 334         /*
 335          * Maybe there is enough stuff pending that calling the interrupt
 336          * throttles us again.  In this case, line->throttled will be 1
 337          * again and we shouldn't turn the interrupt back on.
 338          */
 339         if (!line->throttled)
 340                 reactivate_chan(&line->chan_list, line->driver->read_irq);
 341 }
 342
 343 static irqreturn_t line_write_interrupt(int irq, void *data)
 344 {
 345         struct chan *chan = data;
 346         struct line *line = chan->line;
 347         struct tty_struct *tty = line->tty;
 348         int err;
 349
 350         /*
 351          * Interrupts are disabled here because we registered the interrupt with
 352          * IRQF_DISABLED (see line_setup_irq).
 353          */
 354
 355         spin_lock(&line->lock);
 356         err = flush_buffer(line);
 357         if (err == 0) {
 358                 return IRQ_NONE;
 359         } else if (err < 0) {
 360                 line->head = line->buffer;
 361                 line->tail = line->buffer;
 362         }
 363         spin_unlock(&line->lock);
 364
 365         if (tty == NULL)
 366                 return IRQ_NONE;
 367
 368         tty_wakeup(tty);
 369         return IRQ_HANDLED;
 370 }
 371
 372 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 373 {
 374         const struct line_driver *driver = line->driver;
 375         int err = 0, flags = IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM;
 376
 377         if (input)
 378                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 379                                        line_interrupt, flags,
 380                                        driver->read_irq_name, data);
 381         if (err)
 382                 return err;
 383         if (output)
 384                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 385                                         line_write_interrupt, flags,
 386                                         driver->write_irq_name, data);
 387         line->have_irq = 1;
 388         return err;
 389 }
 390
 391 /*
 392  * Normally, a driver like this can rely mostly on the tty layer
 393  * locking, particularly when it comes to the driver structure.
 394  * However, in this case, mconsole requests can come in "from the
 395  * side", and race with opens and closes.
 396  *
 397  * mconsole config requests will want to be sure the device isn't in
 398  * use, and get_config, open, and close will want a stable
 399  * configuration.  The checking and modification of the configuration
 400  * is done under a spinlock.  Checking whether the device is in use is
 401  * line->tty->count > 1, also under the spinlock.
 402  *
 403  * tty->count serves to decide whether the device should be enabled or
 404  * disabled on the host.  If it's equal to 1, then we are doing the
 405  * first open or last close.  Otherwise, open and close just return.
 406  */
 407
 408 int line_open(struct line *lines, struct tty_struct *tty)
 409 {
 410         struct line *line = &lines[tty->index];
 411         int err = -ENODEV;
 412
 413         spin_lock(&line->count_lock);
 414         if (!line->valid)
 415                 goto out_unlock;
 416
 417         err = 0;
 418         if (tty->count > 1)
 419                 goto out_unlock;
 420
 421         spin_unlock(&line->count_lock);
 422
 423         tty->driver_data = line;
 424         line->tty = tty;
 425
 426         err = enable_chan(line);
 427         if (err)
 428                 return err;
 429
 430         INIT_DELAYED_WORK(&line->task, line_timer_cb);
 431
 432         if (!line->sigio) {
 433                 chan_enable_winch(&line->chan_list, tty);
 434                 line->sigio = 1;
 435         }
 436
 437         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 438                          &tty->winsize.ws_col);
 439
 440         return err;
 441
 442 out_unlock:
 443         spin_unlock(&line->count_lock);
 444         return err;
 445 }
 446
 447 static void unregister_winch(struct tty_struct *tty);
 448
 449 void line_close(struct tty_struct *tty, struct file * filp)
 450 {
 451         struct line *line = tty->driver_data;
 452
 453         /*
 454          * If line_open fails (and tty->driver_data is never set),
 455          * tty_open will call line_close.  So just return in this case.
 456          */
 457         if (line == NULL)
 458                 return;
 459
 460         /* We ignore the error anyway! */
 461         flush_buffer(line);
 462
 463         spin_lock(&line->count_lock);
 464         if (!line->valid)
 465                 goto out_unlock;
 466
 467         if (tty->count > 1)
 468                 goto out_unlock;
 469
 470         spin_unlock(&line->count_lock);
 471
 472         line->tty = NULL;
 473         tty->driver_data = NULL;
 474
 475         if (line->sigio) {
 476                 unregister_winch(tty);
 477                 line->sigio = 0;
 478         }
 479
 480         return;
 481
 482 out_unlock:
 483         spin_unlock(&line->count_lock);
 484 }
 485
 486 void close_lines(struct line *lines, int nlines)
 487 {
 488         int i;
 489
 490         for(i = 0; i < nlines; i++)
 491                 close_chan(&lines[i].chan_list, 0);
 492 }
 493
 494 static int setup_one_line(struct line *lines, int n, char *init, int init_prio,
 495                           char **error_out)
 496 {
 497         struct line *line = &lines[n];
 498         int err = -EINVAL;
 499
 500         spin_lock(&line->count_lock);
 501
 502         if (line->tty != NULL) {
 503                 *error_out = "Device is already open";
 504                 goto out;
 505         }
 506
 507         if (line->init_pri <= init_prio) {
 508                 line->init_pri = init_prio;
 509                 if (!strcmp(init, "none"))
 510                         line->valid = 0;
 511                 else {
 512                         line->init_str = init;
 513                         line->valid = 1;
 514                 }
 515         }
 516         err = 0;
 517 out:
 518         spin_unlock(&line->count_lock);
 519         return err;
 520 }
 521
 522 /*
 523  * Common setup code for both startup command line and mconsole initialization.
 524  * @lines contains the array (of size @num) to modify;
 525  * @init is the setup string;
 526  * @error_out is an error string in the case of failure;
 527  */
 528
 529 int line_setup(struct line *lines, unsigned int num, char *init,
 530                char **error_out)
 531 {
 532         int i, n, err;
 533         char *end;
 534
 535         if (*init == '=') {
 536                 /*
 537                  * We said con=/ssl= instead of con#=, so we are configuring all
 538                  * consoles at once.
 539                  */
 540                 n = -1;
 541         }
 542         else {
 543                 n = simple_strtoul(init, &end, 0);
 544                 if (*end != '=') {
 545                         *error_out = "Couldn't parse device number";
 546                         return -EINVAL;
 547                 }
 548                 init = end;
 549         }
 550         init++;
 551
 552         if (n >= (signed int) num) {
 553                 *error_out = "Device number out of range";
 554                 return -EINVAL;
 555         }
 556         else if (n >= 0) {
 557                 err = setup_one_line(lines, n, init, INIT_ONE, error_out);
 558                 if (err)
 559                         return err;
 560         }
 561         else {
 562                 for(i = 0; i < num; i++) {
 563                         err = setup_one_line(lines, i, init, INIT_ALL,
 564                                              error_out);
 565                         if (err)
 566                                 return err;
 567                 }
 568         }
 569         return n == -1 ? num : n;
 570 }
 571
 572 int line_config(struct line *lines, unsigned int num, char *str,
 573                 const struct chan_opts *opts, char **error_out)
 574 {
 575         struct line *line;
 576         char *new;
 577         int n;
 578
 579         if (*str == '=') {
 580                 *error_out = "Can't configure all devices from mconsole";
 581                 return -EINVAL;
 582         }
 583
 584         new = kstrdup(str, GFP_KERNEL);
 585         if (new == NULL) {
 586                 *error_out = "Failed to allocate memory";
 587                 return -ENOMEM;
 588         }
 589         n = line_setup(lines, num, new, error_out);
 590         if (n < 0)
 591                 return n;
 592
 593         line = &lines[n];
 594         return parse_chan_pair(line->init_str, line, n, opts, error_out);
 595 }
 596
 597 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 598                     int size, char **error_out)
 599 {
 600         struct line *line;
 601         char *end;
 602         int dev, n = 0;
 603
 604         dev = simple_strtoul(name, &end, 0);
 605         if ((*end != '\0') || (end == name)) {
 606                 *error_out = "line_get_config failed to parse device number";
 607                 return 0;
 608         }
 609
 610         if ((dev < 0) || (dev >= num)) {
 611                 *error_out = "device number out of range";
 612                 return 0;
 613         }
 614
 615         line = &lines[dev];
 616
 617         spin_lock(&line->count_lock);
 618         if (!line->valid)
 619                 CONFIG_CHUNK(str, size, n, "none", 1);
 620         else if (line->tty == NULL)
 621                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 622         else n = chan_config_string(&line->chan_list, str, size, error_out);
 623         spin_unlock(&line->count_lock);
 624
 625         return n;
 626 }
 627
 628 int line_id(char **str, int *start_out, int *end_out)
 629 {
 630         char *end;
 631         int n;
 632
 633         n = simple_strtoul(*str, &end, 0);
 634         if ((*end != '\0') || (end == *str))
 635                 return -1;
 636
 637         *str = end;
 638         *start_out = n;
 639         *end_out = n;
 640         return n;
 641 }
 642
 643 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 644 {
 645         int err;
 646         char config[sizeof("conxxxx=none\0")];
 647
 648         sprintf(config, "%d=none", n);
 649         err = line_setup(lines, num, config, error_out);
 650         if (err >= 0)
 651                 err = 0;
 652         return err;
 653 }
 654
 655 struct tty_driver *register_lines(struct line_driver *line_driver,
 656                                   const struct tty_operations *ops,
 657                                   struct line *lines, int nlines)
 658 {
 659         int i;
 660         struct tty_driver *driver = alloc_tty_driver(nlines);
 661
 662         if (!driver)
 663                 return NULL;
 664
 665         driver->driver_name = line_driver->name;
 666         driver->name = line_driver->device_name;
 667         driver->major = line_driver->major;
 668         driver->minor_start = line_driver->minor_start;
 669         driver->type = line_driver->type;
 670         driver->subtype = line_driver->subtype;
 671         driver->flags = TTY_DRIVER_REAL_RAW;
 672         driver->init_termios = tty_std_termios;
 673         tty_set_operations(driver, ops);
 674
 675         if (tty_register_driver(driver)) {
 676                 printk(KERN_ERR "register_lines : can't register %s driver\n",
 677                        line_driver->name);
 678                 put_tty_driver(driver);
 679                 return NULL;
 680         }
 681
 682         for(i = 0; i < nlines; i++) {
 683                 if (!lines[i].valid)
 684                         tty_unregister_device(driver, i);
 685         }
 686
 687         mconsole_register_dev(&line_driver->mc);
 688         return driver;
 689 }
 690
 691 static DEFINE_SPINLOCK(winch_handler_lock);
 692 static LIST_HEAD(winch_handlers);
 693
 694 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 695 {
 696         struct line *line;
 697         char *error;
 698         int i;
 699
 700         for(i = 0; i < nlines; i++) {
 701                 line = &lines[i];
 702                 INIT_LIST_HEAD(&line->chan_list);
 703
 704                 if (line->init_str == NULL)
 705                         continue;
 706
 707                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
 708                 if (line->init_str == NULL)
 709                         printk(KERN_ERR "lines_init - kstrdup returned NULL\n");
 710
 711                 if (parse_chan_pair(line->init_str, line, i, opts, &error)) {
 712                         printk(KERN_ERR "parse_chan_pair failed for "
 713                                "device %d : %s\n", i, error);
 714                         line->valid = 0;
 715                 }
 716         }
 717 }
 718
 719 struct winch {
 720         struct list_head list;
 721         int fd;
 722         int tty_fd;
 723         int pid;
 724         struct tty_struct *tty;
 725         unsigned long stack;
 726 };
 727
 728 static void free_winch(struct winch *winch, int free_irq_ok)
 729 {
 730         if (free_irq_ok)
 731                 free_irq(WINCH_IRQ, winch);
 732
 733         list_del(&winch->list);
 734
 735         if (winch->pid != -1)
 736                 os_kill_process(winch->pid, 1);
 737         if (winch->fd != -1)
 738                 os_close_file(winch->fd);
 739         if (winch->stack != 0)
 740                 free_stack(winch->stack, 0);
 741         kfree(winch);
 742 }
 743
 744 static irqreturn_t winch_interrupt(int irq, void *data)
 745 {
 746         struct winch *winch = data;
 747         struct tty_struct *tty;
 748         struct line *line;
 749         int err;
 750         char c;
 751
 752         if (winch->fd != -1) {
 753                 err = generic_read(winch->fd, &c, NULL);
 754                 if (err < 0) {
 755                         if (err != -EAGAIN) {
 756                                 printk(KERN_ERR "winch_interrupt : "
 757                                        "read failed, errno = %d\n", -err);
 758                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
 759                                        "support\n", winch->tty_fd);
 760                                 free_winch(winch, 0);
 761                                 return IRQ_HANDLED;
 762                         }
 763                         goto out;
 764                 }
 765         }
 766         tty = winch->tty;
 767         if (tty != NULL) {
 768                 line = tty->driver_data;
 769                 if (line != NULL) {
 770                         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 771                                          &tty->winsize.ws_col);
 772                         kill_pgrp(tty->pgrp, SIGWINCH, 1);
 773                 }
 774         }
 775  out:
 776         if (winch->fd != -1)
 777                 reactivate_fd(winch->fd, WINCH_IRQ);
 778         return IRQ_HANDLED;
 779 }
 780
 781 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
 782                         unsigned long stack)
 783 {
 784         struct winch *winch;
 785
 786         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 787         if (winch == NULL) {
 788                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
 789                 goto cleanup;
 790         }
 791
 792         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 793                                    .fd          = fd,
 794                                    .tty_fd      = tty_fd,
 795                                    .pid         = pid,
 796                                    .tty         = tty,
 797                                    .stack       = stack });
 798
 799         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 800                            IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 801                            "winch", winch) < 0) {
 802                 printk(KERN_ERR "register_winch_irq - failed to register "
 803                        "IRQ\n");
 804                 goto out_free;
 805         }
 806
 807         spin_lock(&winch_handler_lock);
 808         list_add(&winch->list, &winch_handlers);
 809         spin_unlock(&winch_handler_lock);
 810
 811         return;
 812
 813  out_free:
 814         kfree(winch);
 815  cleanup:
 816         os_kill_process(pid, 1);
 817         os_close_file(fd);
 818         if (stack != 0)
 819                 free_stack(stack, 0);
 820 }
 821
 822 static void unregister_winch(struct tty_struct *tty)
 823 {
 824         struct list_head *ele, *next;
 825         struct winch *winch;
 826
 827         spin_lock(&winch_handler_lock);
 828
 829         list_for_each_safe(ele, next, &winch_handlers) {
 830                 winch = list_entry(ele, struct winch, list);
 831                 if (winch->tty == tty) {
 832                         free_winch(winch, 1);
 833                         break;
 834                 }
 835         }
 836         spin_unlock(&winch_handler_lock);
 837 }
 838
 839 static void winch_cleanup(void)
 840 {
 841         struct list_head *ele, *next;
 842         struct winch *winch;
 843
 844         spin_lock(&winch_handler_lock);
 845
 846         list_for_each_safe(ele, next, &winch_handlers) {
 847                 winch = list_entry(ele, struct winch, list);
 848                 free_winch(winch, 1);
 849         }
 850
 851         spin_unlock(&winch_handler_lock);
 852 }
 853 __uml_exitcall(winch_cleanup);
 854
 855 char *add_xterm_umid(char *base)
 856 {
 857         char *umid, *title;
 858         int len;
 859
 860         umid = get_umid();
 861         if (*umid == '\0')
 862                 return base;
 863
 864         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 865         title = kmalloc(len, GFP_KERNEL);
 866         if (title == NULL) {
 867                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
 868                 return base;
 869         }
 870
 871         snprintf(title, len, "%s (%s)", base, umid);
 872         return title;
 873 }