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