arch/um/drivers/line.c

   1 /*
   2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/irqreturn.h"
   7 #include "linux/kd.h"
   8 #include "chan_kern.h"
   9 #include "irq_kern.h"
  10 #include "irq_user.h"
  11 #include "kern_util.h"
  12 #include "os.h"
  13
  14 #define LINE_BUFSIZE 4096
  15
  16 static irqreturn_t line_interrupt(int irq, void *data)
  17 {
  18         struct chan *chan = data;
  19         struct line *line = chan->line;
  20         struct tty_struct *tty = line->tty;
  21
  22         if (line)
  23                 chan_interrupt(&line->chan_list, &line->task, tty, irq);
  24         return IRQ_HANDLED;
  25 }
  26
  27 static void line_timer_cb(struct work_struct *work)
  28 {
  29         struct line *line = container_of(work, struct line, task.work);
  30
  31         if (!line->throttled)
  32                 chan_interrupt(&line->chan_list, &line->task, line->tty,
  33                                line->driver->read_irq);
  34 }
  35
  36 /*
  37  * Returns the free space inside the ring buffer of this line.
  38  *
  39  * Should be called while holding line->lock (this does not modify data).
  40  */
  41 static int write_room(struct line *line)
  42 {
  43         int n;
  44
  45         if (line->buffer == NULL)
  46                 return LINE_BUFSIZE - 1;
  47
  48         /* This is for the case where the buffer is wrapped! */
  49         n = line->head - line->tail;
  50
  51         if (n <= 0)
  52                 n += LINE_BUFSIZE; /* The other case */
  53         return n - 1;
  54 }
  55
  56 int line_write_room(struct tty_struct *tty)
  57 {
  58         struct line *line = tty->driver_data;
  59         unsigned long flags;
  60         int room;
  61
  62         spin_lock_irqsave(&line->lock, flags);
  63         room = write_room(line);
  64         spin_unlock_irqrestore(&line->lock, flags);
  65
  66         return room;
  67 }
  68
  69 int line_chars_in_buffer(struct tty_struct *tty)
  70 {
  71         struct line *line = tty->driver_data;
  72         unsigned long flags;
  73         int ret;
  74
  75         spin_lock_irqsave(&line->lock, flags);
  76         /* write_room subtracts 1 for the needed NULL, so we readd it.*/
  77         ret = LINE_BUFSIZE - (write_room(line) + 1);
  78         spin_unlock_irqrestore(&line->lock, flags);
  79
  80         return ret;
  81 }
  82
  83 /*
  84  * This copies the content of buf into the circular buffer associated with
  85  * this line.
  86  * The return value is the number of characters actually copied, i.e. the ones
  87  * for which there was space: this function is not supposed to ever flush out
  88  * the circular buffer.
  89  *
  90  * Must be called while holding line->lock!
  91  */
  92 static int buffer_data(struct line *line, const char *buf, int len)
  93 {
  94         int end, room;
  95
  96         if (line->buffer == NULL) {
  97                 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
  98                 if (line->buffer == NULL) {
  99                         printk(KERN_ERR "buffer_data - atomic allocation "
 100                                "failed\n");
 101                         return 0;
 102                 }
 103                 line->head = line->buffer;
 104                 line->tail = line->buffer;
 105         }
 106
 107         room = write_room(line);
 108         len = (len > room) ? room : len;
 109
 110         end = line->buffer + LINE_BUFSIZE - line->tail;
 111
 112         if (len < end) {
 113                 memcpy(line->tail, buf, len);
 114                 line->tail += len;
 115         }
 116         else {
 117                 /* The circular buffer is wrapping */
 118                 memcpy(line->tail, buf, end);
 119                 buf += end;
 120                 memcpy(line->buffer, buf, len - end);
 121                 line->tail = line->buffer + len - end;
 122         }
 123
 124         return len;
 125 }
 126
 127 /*
 128  * Flushes the ring buffer to the output channels. That is, write_chan is
 129  * called, passing it line->head as buffer, and an appropriate count.
 130  *
 131  * On exit, returns 1 when the buffer is empty,
 132  * 0 when the buffer is not empty on exit,
 133  * and -errno when an error occurred.
 134  *
 135  * Must be called while holding line->lock!*/
 136 static int flush_buffer(struct line *line)
 137 {
 138         int n, count;
 139
 140         if ((line->buffer == NULL) || (line->head == line->tail))
 141                 return 1;
 142
 143         if (line->tail < line->head) {
 144                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
 145                 count = line->buffer + LINE_BUFSIZE - line->head;
 146
 147                 n = write_chan(&line->chan_list, line->head, count,
 148                                line->driver->write_irq);
 149                 if (n < 0)
 150                         return n;
 151                 if (n == count) {
 152                         /*
 153                          * We have flushed from ->head to buffer end, now we
 154                          * must flush only from the beginning to ->tail.
 155                          */
 156                         line->head = line->buffer;
 157                 } else {
 158                         line->head += n;
 159                         return 0;
 160                 }
 161         }
 162
 163         count = line->tail - line->head;
 164         n = write_chan(&line->chan_list, line->head, count,
 165                        line->driver->write_irq);
 166
 167         if (n < 0)
 168                 return n;
 169
 170         line->head += n;
 171         return line->head == line->tail;
 172 }
 173
 174 void line_flush_buffer(struct tty_struct *tty)
 175 {
 176         struct line *line = tty->driver_data;
 177         unsigned long flags;
 178         int err;
 179
 180         spin_lock_irqsave(&line->lock, flags);
 181         err = flush_buffer(line);
 182         spin_unlock_irqrestore(&line->lock, flags);
 183 }
 184
 185 /*
 186  * We map both ->flush_chars and ->put_char (which go in pair) onto
 187  * ->flush_buffer and ->write. Hope it's not that bad.
 188  */
 189 void line_flush_chars(struct tty_struct *tty)
 190 {
 191         line_flush_buffer(tty);
 192 }
 193
 194 int line_put_char(struct tty_struct *tty, unsigned char ch)
 195 {
 196         return line_write(tty, &ch, sizeof(ch));
 197 }
 198
 199 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
 200 {
 201         struct line *line = tty->driver_data;
 202         unsigned long flags;
 203         int n, ret = 0;
 204
 205         spin_lock_irqsave(&line->lock, flags);
 206         if (line->head != line->tail)
 207                 ret = buffer_data(line, buf, len);
 208         else {
 209                 n = write_chan(&line->chan_list, buf, len,
 210                                line->driver->write_irq);
 211                 if (n < 0) {
 212                         ret = n;
 213                         goto out_up;
 214                 }
 215
 216                 len -= n;
 217                 ret += n;
 218                 if (len > 0)
 219                         ret += buffer_data(line, buf + n, len);
 220         }
 221 out_up:
 222         spin_unlock_irqrestore(&line->lock, flags);
 223         return ret;
 224 }
 225
 226 void line_set_termios(struct tty_struct *tty, struct ktermios * old)
 227 {
 228         /* nothing */
 229 }
 230
 231 static const struct {
 232         int  cmd;
 233         char *level;
 234         char *name;
 235 } tty_ioctls[] = {
 236         /* don't print these, they flood the log ... */
 237         { TCGETS,      NULL,       "TCGETS"      },
 238         { TCSETS,      NULL,       "TCSETS"      },
 239         { TCSETSW,     NULL,       "TCSETSW"     },
 240         { TCFLSH,      NULL,       "TCFLSH"      },
 241         { TCSBRK,      NULL,       "TCSBRK"      },
 242
 243         /* general tty stuff */
 244         { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
 245         { TCGETA,      KERN_DEBUG, "TCGETA"      },
 246         { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
 247         { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
 248         { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
 249
 250         /* linux-specific ones */
 251         { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
 252         { KDGKBMODE,   KERN_INFO,  "KDGKBMODE"   },
 253         { KDGKBTYPE,   KERN_INFO,  "KDGKBTYPE"   },
 254         { KDSIGACCEPT, KERN_INFO,  "KDSIGACCEPT" },
 255 };
 256
 257 int line_ioctl(struct tty_struct *tty, struct file * file,
 258                unsigned int cmd, unsigned long arg)
 259 {
 260         int ret;
 261         int i;
 262
 263         ret = 0;
 264         switch(cmd) {
 265 #ifdef TIOCGETP
 266         case TIOCGETP:
 267         case TIOCSETP:
 268         case TIOCSETN:
 269 #endif
 270 #ifdef TIOCGETC
 271         case TIOCGETC:
 272         case TIOCSETC:
 273 #endif
 274 #ifdef TIOCGLTC
 275         case TIOCGLTC:
 276         case TIOCSLTC:
 277 #endif
 278         /* Note: these are out of date as we now have TCGETS2 etc but this
 279            whole lot should probably go away */
 280         case TCGETS:
 281         case TCSETSF:
 282         case TCSETSW:
 283         case TCSETS:
 284         case TCGETA:
 285         case TCSETAF:
 286         case TCSETAW:
 287         case TCSETA:
 288         case TCXONC:
 289         case TCFLSH:
 290         case TIOCOUTQ:
 291         case TIOCINQ:
 292         case TIOCGLCKTRMIOS:
 293         case TIOCSLCKTRMIOS:
 294         case TIOCPKT:
 295         case TIOCGSOFTCAR:
 296         case TIOCSSOFTCAR:
 297                 return -ENOIOCTLCMD;
 298 #if 0
 299         case TCwhatever:
 300                 /* do something */
 301                 break;
 302 #endif
 303         default:
 304                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
 305                         if (cmd == tty_ioctls[i].cmd)
 306                                 break;
 307                 if (i == ARRAY_SIZE(tty_ioctls)) {
 308                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
 309                                __func__, tty->name, cmd);
 310                 }
 311                 ret = -ENOIOCTLCMD;
 312                 break;
 313         }
 314         return ret;
 315 }
 316
 317 void line_throttle(struct tty_struct *tty)
 318 {
 319         struct line *line = tty->driver_data;
 320
 321         deactivate_chan(&line->chan_list, line->driver->read_irq);
 322         line->throttled = 1;
 323 }
 324
 325 void line_unthrottle(struct tty_struct *tty)
 326 {
 327         struct line *line = tty->driver_data;
 328
 329         line->throttled = 0;
 330         chan_interrupt(&line->chan_list, &line->task, tty,
 331                        line->driver->read_irq);
 332
 333         /*
 334          * Maybe there is enough stuff pending that calling the interrupt
 335          * throttles us again.  In this case, line->throttled will be 1
 336          * again and we shouldn't turn the interrupt back on.
 337          */
 338         if (!line->throttled)
 339                 reactivate_chan(&line->chan_list, line->driver->read_irq);
 340 }
 341
 342 static irqreturn_t line_write_interrupt(int irq, void *data)
 343 {
 344         struct chan *chan = data;
 345         struct line *line = chan->line;
 346         struct tty_struct *tty = line->tty;
 347         int err;
 348
 349         /*
 350          * Interrupts are disabled here because we registered the interrupt with
 351          * IRQF_DISABLED (see line_setup_irq).
 352          */
 353
 354         spin_lock(&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(&line->lock);
 363
 364         if (tty == NULL)
 365                 return IRQ_NONE;
 366
 367         tty_wakeup(tty);
 368         return IRQ_HANDLED;
 369 }
 370
 371 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 372 {
 373         const struct line_driver *driver = line->driver;
 374         int err = 0, flags = IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM;
 375
 376         if (input)
 377                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 378                                        line_interrupt, flags,
 379                                        driver->read_irq_name, data);
 380         if (err)
 381                 return err;
 382         if (output)
 383                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 384                                         line_write_interrupt, flags,
 385                                         driver->write_irq_name, data);
 386         line->have_irq = 1;
 387         return err;
 388 }
 389
 390 /*
 391  * Normally, a driver like this can rely mostly on the tty layer
 392  * locking, particularly when it comes to the driver structure.
 393  * However, in this case, mconsole requests can come in "from the
 394  * side", and race with opens and closes.
 395  *
 396  * mconsole config requests will want to be sure the device isn't in
 397  * use, and get_config, open, and close will want a stable
 398  * configuration.  The checking and modification of the configuration
 399  * is done under a spinlock.  Checking whether the device is in use is
 400  * line->tty->count > 1, also under the spinlock.
 401  *
 402  * tty->count serves to decide whether the device should be enabled or
 403  * disabled on the host.  If it's equal to 1, then we are doing the
 404  * first open or last close.  Otherwise, open and close just return.
 405  */
 406
 407 int line_open(struct line *lines, struct tty_struct *tty)
 408 {
 409         struct line *line = &lines[tty->index];
 410         int err = -ENODEV;
 411
 412         spin_lock(&line->count_lock);
 413         if (!line->valid)
 414                 goto out_unlock;
 415
 416         err = 0;
 417         if (tty->count > 1)
 418                 goto out_unlock;
 419
 420         spin_unlock(&line->count_lock);
 421
 422         tty->driver_data = line;
 423         line->tty = tty;
 424
 425         err = enable_chan(line);
 426         if (err)
 427                 return err;
 428
 429         INIT_DELAYED_WORK(&line->task, line_timer_cb);
 430
 431         if (!line->sigio) {
 432                 chan_enable_winch(&line->chan_list, tty);
 433                 line->sigio = 1;
 434         }
 435
 436         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 437                          &tty->winsize.ws_col);
 438
 439         return err;
 440
 441 out_unlock:
 442         spin_unlock(&line->count_lock);
 443         return err;
 444 }
 445
 446 static void unregister_winch(struct tty_struct *tty);
 447
 448 void line_close(struct tty_struct *tty, struct file * filp)
 449 {
 450         struct line *line = tty->driver_data;
 451
 452         /*
 453          * If line_open fails (and tty->driver_data is never set),
 454          * tty_open will call line_close.  So just return in this case.
 455          */
 456         if (line == NULL)
 457                 return;
 458
 459         /* We ignore the error anyway! */
 460         flush_buffer(line);
 461
 462         spin_lock(&line->count_lock);
 463         if (!line->valid)
 464                 goto out_unlock;
 465
 466         if (tty->count > 1)
 467                 goto out_unlock;
 468
 469         spin_unlock(&line->count_lock);
 470
 471         line->tty = NULL;
 472         tty->driver_data = NULL;
 473
 474         if (line->sigio) {
 475                 unregister_winch(tty);
 476                 line->sigio = 0;
 477         }
 478
 479         return;
 480
 481 out_unlock:
 482         spin_unlock(&line->count_lock);
 483 }
 484
 485 void close_lines(struct line *lines, int nlines)
 486 {
 487         int i;
 488
 489         for(i = 0; i < nlines; i++)
 490                 close_chan(&lines[i].chan_list, 0);
 491 }
 492
 493 static int setup_one_line(struct line *lines, int n, char *init, int init_prio,
 494                           char **error_out)
 495 {
 496         struct line *line = &lines[n];
 497         int err = -EINVAL;
 498
 499         spin_lock(&line->count_lock);
 500
 501         if (line->tty != NULL) {
 502                 *error_out = "Device is already open";
 503                 goto out;
 504         }
 505
 506         if (line->init_pri <= init_prio) {
 507                 line->init_pri = init_prio;
 508                 if (!strcmp(init, "none"))
 509                         line->valid = 0;
 510                 else {
 511                         line->init_str = init;
 512                         line->valid = 1;
 513                 }
 514         }
 515         err = 0;
 516 out:
 517         spin_unlock(&line->count_lock);
 518         return err;
 519 }
 520
 521 /*
 522  * Common setup code for both startup command line and mconsole initialization.
 523  * @lines contains the array (of size @num) to modify;
 524  * @init is the setup string;
 525  * @error_out is an error string in the case of failure;
 526  */
 527
 528 int line_setup(struct line *lines, unsigned int num, char *init,
 529                char **error_out)
 530 {
 531         int i, n, err;
 532         char *end;
 533
 534         if (*init == '=') {
 535                 /*
 536                  * We said con=/ssl= instead of con#=, so we are configuring all
 537                  * consoles at once.
 538                  */
 539                 n = -1;
 540         }
 541         else {
 542                 n = simple_strtoul(init, &end, 0);
 543                 if (*end != '=') {
 544                         *error_out = "Couldn't parse device number";
 545                         return -EINVAL;
 546                 }
 547                 init = end;
 548         }
 549         init++;
 550
 551         if (n >= (signed int) num) {
 552                 *error_out = "Device number out of range";
 553                 return -EINVAL;
 554         }
 555         else if (n >= 0) {
 556                 err = setup_one_line(lines, n, init, INIT_ONE, error_out);
 557                 if (err)
 558                         return err;
 559         }
 560         else {
 561                 for(i = 0; i < num; i++) {
 562                         err = setup_one_line(lines, i, init, INIT_ALL,
 563                                              error_out);
 564                         if (err)
 565                                 return err;
 566                 }
 567         }
 568         return n == -1 ? num : n;
 569 }
 570
 571 int line_config(struct line *lines, unsigned int num, char *str,
 572                 const struct chan_opts *opts, char **error_out)
 573 {
 574         struct line *line;
 575         char *new;
 576         int n;
 577
 578         if (*str == '=') {
 579                 *error_out = "Can't configure all devices from mconsole";
 580                 return -EINVAL;
 581         }
 582
 583         new = kstrdup(str, GFP_KERNEL);
 584         if (new == NULL) {
 585                 *error_out = "Failed to allocate memory";
 586                 return -ENOMEM;
 587         }
 588         n = line_setup(lines, num, new, error_out);
 589         if (n < 0)
 590                 return n;
 591
 592         line = &lines[n];
 593         return parse_chan_pair(line->init_str, line, n, opts, error_out);
 594 }
 595
 596 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 597                     int size, char **error_out)
 598 {
 599         struct line *line;
 600         char *end;
 601         int dev, n = 0;
 602
 603         dev = simple_strtoul(name, &end, 0);
 604         if ((*end != '\0') || (end == name)) {
 605                 *error_out = "line_get_config failed to parse device number";
 606                 return 0;
 607         }
 608
 609         if ((dev < 0) || (dev >= num)) {
 610                 *error_out = "device number out of range";
 611                 return 0;
 612         }
 613
 614         line = &lines[dev];
 615
 616         spin_lock(&line->count_lock);
 617         if (!line->valid)
 618                 CONFIG_CHUNK(str, size, n, "none", 1);
 619         else if (line->tty == NULL)
 620                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 621         else n = chan_config_string(&line->chan_list, str, size, error_out);
 622         spin_unlock(&line->count_lock);
 623
 624         return n;
 625 }
 626
 627 int line_id(char **str, int *start_out, int *end_out)
 628 {
 629         char *end;
 630         int n;
 631
 632         n = simple_strtoul(*str, &end, 0);
 633         if ((*end != '\0') || (end == *str))
 634                 return -1;
 635
 636         *str = end;
 637         *start_out = n;
 638         *end_out = n;
 639         return n;
 640 }
 641
 642 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 643 {
 644         int err;
 645         char config[sizeof("conxxxx=none\0")];
 646
 647         sprintf(config, "%d=none", n);
 648         err = line_setup(lines, num, config, error_out);
 649         if (err >= 0)
 650                 err = 0;
 651         return err;
 652 }
 653
 654 struct tty_driver *register_lines(struct line_driver *line_driver,
 655                                   const struct tty_operations *ops,
 656                                   struct line *lines, int nlines)
 657 {
 658         int i;
 659         struct tty_driver *driver = alloc_tty_driver(nlines);
 660
 661         if (!driver)
 662                 return NULL;
 663
 664         driver->driver_name = line_driver->name;
 665         driver->name = line_driver->device_name;
 666         driver->major = line_driver->major;
 667         driver->minor_start = line_driver->minor_start;
 668         driver->type = line_driver->type;
 669         driver->subtype = line_driver->subtype;
 670         driver->flags = TTY_DRIVER_REAL_RAW;
 671         driver->init_termios = tty_std_termios;
 672         tty_set_operations(driver, ops);
 673
 674         if (tty_register_driver(driver)) {
 675                 printk(KERN_ERR "register_lines : can't register %s driver\n",
 676                        line_driver->name);
 677                 put_tty_driver(driver);
 678                 return NULL;
 679         }
 680
 681         for(i = 0; i < nlines; i++) {
 682                 if (!lines[i].valid)
 683                         tty_unregister_device(driver, i);
 684         }
 685
 686         mconsole_register_dev(&line_driver->mc);
 687         return driver;
 688 }
 689
 690 static DEFINE_SPINLOCK(winch_handler_lock);
 691 static LIST_HEAD(winch_handlers);
 692
 693 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 694 {
 695         struct line *line;
 696         char *error;
 697         int i;
 698
 699         for(i = 0; i < nlines; i++) {
 700                 line = &lines[i];
 701                 INIT_LIST_HEAD(&line->chan_list);
 702
 703                 if (line->init_str == NULL)
 704                         continue;
 705
 706                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
 707                 if (line->init_str == NULL)
 708                         printk(KERN_ERR "lines_init - kstrdup returned NULL\n");
 709
 710                 if (parse_chan_pair(line->init_str, line, i, opts, &error)) {
 711                         printk(KERN_ERR "parse_chan_pair failed for "
 712                                "device %d : %s\n", i, error);
 713                         line->valid = 0;
 714                 }
 715         }
 716 }
 717
 718 struct winch {
 719         struct list_head list;
 720         int fd;
 721         int tty_fd;
 722         int pid;
 723         struct tty_struct *tty;
 724         unsigned long stack;
 725 };
 726
 727 static void free_winch(struct winch *winch, int free_irq_ok)
 728 {
 729         list_del(&winch->list);
 730
 731         if (winch->pid != -1)
 732                 os_kill_process(winch->pid, 1);
 733         if (winch->fd != -1)
 734                 os_close_file(winch->fd);
 735         if (winch->stack != 0)
 736                 free_stack(winch->stack, 0);
 737         if (free_irq_ok)
 738                 free_irq(WINCH_IRQ, winch);
 739         kfree(winch);
 740 }
 741
 742 static irqreturn_t winch_interrupt(int irq, void *data)
 743 {
 744         struct winch *winch = data;
 745         struct tty_struct *tty;
 746         struct line *line;
 747         int err;
 748         char c;
 749
 750         if (winch->fd != -1) {
 751                 err = generic_read(winch->fd, &c, NULL);
 752                 if (err < 0) {
 753                         if (err != -EAGAIN) {
 754                                 printk(KERN_ERR "winch_interrupt : "
 755                                        "read failed, errno = %d\n", -err);
 756                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
 757                                        "support\n", winch->tty_fd);
 758                                 free_winch(winch, 0);
 759                                 return IRQ_HANDLED;
 760                         }
 761                         goto out;
 762                 }
 763         }
 764         tty = winch->tty;
 765         if (tty != NULL) {
 766                 line = tty->driver_data;
 767                 if (line != NULL) {
 768                         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 769                                          &tty->winsize.ws_col);
 770                         kill_pgrp(tty->pgrp, SIGWINCH, 1);
 771                 }
 772         }
 773  out:
 774         if (winch->fd != -1)
 775                 reactivate_fd(winch->fd, WINCH_IRQ);
 776         return IRQ_HANDLED;
 777 }
 778
 779 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
 780                         unsigned long stack)
 781 {
 782         struct winch *winch;
 783
 784         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 785         if (winch == NULL) {
 786                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
 787                 goto cleanup;
 788         }
 789
 790         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 791                                    .fd          = fd,
 792                                    .tty_fd      = tty_fd,
 793                                    .pid         = pid,
 794                                    .tty         = tty,
 795                                    .stack       = stack });
 796
 797         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 798                            IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 799                            "winch", winch) < 0) {
 800                 printk(KERN_ERR "register_winch_irq - failed to register "
 801                        "IRQ\n");
 802                 goto out_free;
 803         }
 804
 805         spin_lock(&winch_handler_lock);
 806         list_add(&winch->list, &winch_handlers);
 807         spin_unlock(&winch_handler_lock);
 808
 809         return;
 810
 811  out_free:
 812         kfree(winch);
 813  cleanup:
 814         os_kill_process(pid, 1);
 815         os_close_file(fd);
 816         if (stack != 0)
 817                 free_stack(stack, 0);
 818 }
 819
 820 static void unregister_winch(struct tty_struct *tty)
 821 {
 822         struct list_head *ele;
 823         struct winch *winch;
 824
 825         spin_lock(&winch_handler_lock);
 826
 827         list_for_each(ele, &winch_handlers) {
 828                 winch = list_entry(ele, struct winch, list);
 829                 if (winch->tty == tty) {
 830                         free_winch(winch, 1);
 831                         break;
 832                 }
 833         }
 834         spin_unlock(&winch_handler_lock);
 835 }
 836
 837 static void winch_cleanup(void)
 838 {
 839         struct list_head *ele, *next;
 840         struct winch *winch;
 841
 842         spin_lock(&winch_handler_lock);
 843
 844         list_for_each_safe(ele, next, &winch_handlers) {
 845                 winch = list_entry(ele, struct winch, list);
 846                 free_winch(winch, 1);
 847         }
 848
 849         spin_unlock(&winch_handler_lock);
 850 }
 851 __uml_exitcall(winch_cleanup);
 852
 853 char *add_xterm_umid(char *base)
 854 {
 855         char *umid, *title;
 856         int len;
 857
 858         umid = get_umid();
 859         if (*umid == '\0')
 860                 return base;
 861
 862         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 863         title = kmalloc(len, GFP_KERNEL);
 864         if (title == NULL) {
 865                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
 866                 return base;
 867         }
 868
 869         snprintf(title, len, "%s (%s)", base, umid);
 870         return title;
 871 }