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         case TCGETS:
 279         case TCSETSF:
 280         case TCSETSW:
 281         case TCSETS:
 282         case TCGETA:
 283         case TCSETAF:
 284         case TCSETAW:
 285         case TCSETA:
 286         case TCXONC:
 287         case TCFLSH:
 288         case TIOCOUTQ:
 289         case TIOCINQ:
 290         case TIOCGLCKTRMIOS:
 291         case TIOCSLCKTRMIOS:
 292         case TIOCPKT:
 293         case TIOCGSOFTCAR:
 294         case TIOCSSOFTCAR:
 295                 return -ENOIOCTLCMD;
 296 #if 0
 297         case TCwhatever:
 298                 /* do something */
 299                 break;
 300 #endif
 301         default:
 302                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
 303                         if (cmd == tty_ioctls[i].cmd)
 304                                 break;
 305                 if (i == ARRAY_SIZE(tty_ioctls)) {
 306                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
 307                                __func__, tty->name, cmd);
 308                 }
 309                 ret = -ENOIOCTLCMD;
 310                 break;
 311         }
 312         return ret;
 313 }
 314
 315 void line_throttle(struct tty_struct *tty)
 316 {
 317         struct line *line = tty->driver_data;
 318
 319         deactivate_chan(&line->chan_list, line->driver->read_irq);
 320         line->throttled = 1;
 321 }
 322
 323 void line_unthrottle(struct tty_struct *tty)
 324 {
 325         struct line *line = tty->driver_data;
 326
 327         line->throttled = 0;
 328         chan_interrupt(&line->chan_list, &line->task, tty,
 329                        line->driver->read_irq);
 330
 331         /*
 332          * Maybe there is enough stuff pending that calling the interrupt
 333          * throttles us again.  In this case, line->throttled will be 1
 334          * again and we shouldn't turn the interrupt back on.
 335          */
 336         if (!line->throttled)
 337                 reactivate_chan(&line->chan_list, line->driver->read_irq);
 338 }
 339
 340 static irqreturn_t line_write_interrupt(int irq, void *data)
 341 {
 342         struct chan *chan = data;
 343         struct line *line = chan->line;
 344         struct tty_struct *tty = line->tty;
 345         int err;
 346
 347         /*
 348          * Interrupts are disabled here because we registered the interrupt with
 349          * IRQF_DISABLED (see line_setup_irq).
 350          */
 351
 352         spin_lock(&line->lock);
 353         err = flush_buffer(line);
 354         if (err == 0) {
 355                 return IRQ_NONE;
 356         } else if (err < 0) {
 357                 line->head = line->buffer;
 358                 line->tail = line->buffer;
 359         }
 360         spin_unlock(&line->lock);
 361
 362         if (tty == NULL)
 363                 return IRQ_NONE;
 364
 365         tty_wakeup(tty);
 366         return IRQ_HANDLED;
 367 }
 368
 369 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 370 {
 371         const struct line_driver *driver = line->driver;
 372         int err = 0, flags = IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM;
 373
 374         if (input)
 375                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 376                                        line_interrupt, flags,
 377                                        driver->read_irq_name, data);
 378         if (err)
 379                 return err;
 380         if (output)
 381                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 382                                         line_write_interrupt, flags,
 383                                         driver->write_irq_name, data);
 384         line->have_irq = 1;
 385         return err;
 386 }
 387
 388 /*
 389  * Normally, a driver like this can rely mostly on the tty layer
 390  * locking, particularly when it comes to the driver structure.
 391  * However, in this case, mconsole requests can come in "from the
 392  * side", and race with opens and closes.
 393  *
 394  * mconsole config requests will want to be sure the device isn't in
 395  * use, and get_config, open, and close will want a stable
 396  * configuration.  The checking and modification of the configuration
 397  * is done under a spinlock.  Checking whether the device is in use is
 398  * line->tty->count > 1, also under the spinlock.
 399  *
 400  * tty->count serves to decide whether the device should be enabled or
 401  * disabled on the host.  If it's equal to 1, then we are doing the
 402  * first open or last close.  Otherwise, open and close just return.
 403  */
 404
 405 int line_open(struct line *lines, struct tty_struct *tty)
 406 {
 407         struct line *line = &lines[tty->index];
 408         int err = -ENODEV;
 409
 410         spin_lock(&line->count_lock);
 411         if (!line->valid)
 412                 goto out_unlock;
 413
 414         err = 0;
 415         if (tty->count > 1)
 416                 goto out_unlock;
 417
 418         spin_unlock(&line->count_lock);
 419
 420         tty->driver_data = line;
 421         line->tty = tty;
 422
 423         err = enable_chan(line);
 424         if (err)
 425                 return err;
 426
 427         INIT_DELAYED_WORK(&line->task, line_timer_cb);
 428
 429         if (!line->sigio) {
 430                 chan_enable_winch(&line->chan_list, tty);
 431                 line->sigio = 1;
 432         }
 433
 434         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 435                          &tty->winsize.ws_col);
 436
 437         return err;
 438
 439 out_unlock:
 440         spin_unlock(&line->count_lock);
 441         return err;
 442 }
 443
 444 static void unregister_winch(struct tty_struct *tty);
 445
 446 void line_close(struct tty_struct *tty, struct file * filp)
 447 {
 448         struct line *line = tty->driver_data;
 449
 450         /*
 451          * If line_open fails (and tty->driver_data is never set),
 452          * tty_open will call line_close.  So just return in this case.
 453          */
 454         if (line == NULL)
 455                 return;
 456
 457         /* We ignore the error anyway! */
 458         flush_buffer(line);
 459
 460         spin_lock(&line->count_lock);
 461         if (!line->valid)
 462                 goto out_unlock;
 463
 464         if (tty->count > 1)
 465                 goto out_unlock;
 466
 467         spin_unlock(&line->count_lock);
 468
 469         line->tty = NULL;
 470         tty->driver_data = NULL;
 471
 472         if (line->sigio) {
 473                 unregister_winch(tty);
 474                 line->sigio = 0;
 475         }
 476
 477         return;
 478
 479 out_unlock:
 480         spin_unlock(&line->count_lock);
 481 }
 482
 483 void close_lines(struct line *lines, int nlines)
 484 {
 485         int i;
 486
 487         for(i = 0; i < nlines; i++)
 488                 close_chan(&lines[i].chan_list, 0);
 489 }
 490
 491 static int setup_one_line(struct line *lines, int n, char *init, int init_prio,
 492                           char **error_out)
 493 {
 494         struct line *line = &lines[n];
 495         int err = -EINVAL;
 496
 497         spin_lock(&line->count_lock);
 498
 499         if (line->tty != NULL) {
 500                 *error_out = "Device is already open";
 501                 goto out;
 502         }
 503
 504         if (line->init_pri <= init_prio) {
 505                 line->init_pri = init_prio;
 506                 if (!strcmp(init, "none"))
 507                         line->valid = 0;
 508                 else {
 509                         line->init_str = init;
 510                         line->valid = 1;
 511                 }
 512         }
 513         err = 0;
 514 out:
 515         spin_unlock(&line->count_lock);
 516         return err;
 517 }
 518
 519 /*
 520  * Common setup code for both startup command line and mconsole initialization.
 521  * @lines contains the array (of size @num) to modify;
 522  * @init is the setup string;
 523  * @error_out is an error string in the case of failure;
 524  */
 525
 526 int line_setup(struct line *lines, unsigned int num, char *init,
 527                char **error_out)
 528 {
 529         int i, n, err;
 530         char *end;
 531
 532         if (*init == '=') {
 533                 /*
 534                  * We said con=/ssl= instead of con#=, so we are configuring all
 535                  * consoles at once.
 536                  */
 537                 n = -1;
 538         }
 539         else {
 540                 n = simple_strtoul(init, &end, 0);
 541                 if (*end != '=') {
 542                         *error_out = "Couldn't parse device number";
 543                         return -EINVAL;
 544                 }
 545                 init = end;
 546         }
 547         init++;
 548
 549         if (n >= (signed int) num) {
 550                 *error_out = "Device number out of range";
 551                 return -EINVAL;
 552         }
 553         else if (n >= 0) {
 554                 err = setup_one_line(lines, n, init, INIT_ONE, error_out);
 555                 if (err)
 556                         return err;
 557         }
 558         else {
 559                 for(i = 0; i < num; i++) {
 560                         err = setup_one_line(lines, i, init, INIT_ALL,
 561                                              error_out);
 562                         if (err)
 563                                 return err;
 564                 }
 565         }
 566         return n == -1 ? num : n;
 567 }
 568
 569 int line_config(struct line *lines, unsigned int num, char *str,
 570                 const struct chan_opts *opts, char **error_out)
 571 {
 572         struct line *line;
 573         char *new;
 574         int n;
 575
 576         if (*str == '=') {
 577                 *error_out = "Can't configure all devices from mconsole";
 578                 return -EINVAL;
 579         }
 580
 581         new = kstrdup(str, GFP_KERNEL);
 582         if (new == NULL) {
 583                 *error_out = "Failed to allocate memory";
 584                 return -ENOMEM;
 585         }
 586         n = line_setup(lines, num, new, error_out);
 587         if (n < 0)
 588                 return n;
 589
 590         line = &lines[n];
 591         return parse_chan_pair(line->init_str, line, n, opts, error_out);
 592 }
 593
 594 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 595                     int size, char **error_out)
 596 {
 597         struct line *line;
 598         char *end;
 599         int dev, n = 0;
 600
 601         dev = simple_strtoul(name, &end, 0);
 602         if ((*end != '\0') || (end == name)) {
 603                 *error_out = "line_get_config failed to parse device number";
 604                 return 0;
 605         }
 606
 607         if ((dev < 0) || (dev >= num)) {
 608                 *error_out = "device number out of range";
 609                 return 0;
 610         }
 611
 612         line = &lines[dev];
 613
 614         spin_lock(&line->count_lock);
 615         if (!line->valid)
 616                 CONFIG_CHUNK(str, size, n, "none", 1);
 617         else if (line->tty == NULL)
 618                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 619         else n = chan_config_string(&line->chan_list, str, size, error_out);
 620         spin_unlock(&line->count_lock);
 621
 622         return n;
 623 }
 624
 625 int line_id(char **str, int *start_out, int *end_out)
 626 {
 627         char *end;
 628         int n;
 629
 630         n = simple_strtoul(*str, &end, 0);
 631         if ((*end != '\0') || (end == *str))
 632                 return -1;
 633
 634         *str = end;
 635         *start_out = n;
 636         *end_out = n;
 637         return n;
 638 }
 639
 640 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 641 {
 642         int err;
 643         char config[sizeof("conxxxx=none\0")];
 644
 645         sprintf(config, "%d=none", n);
 646         err = line_setup(lines, num, config, error_out);
 647         if (err >= 0)
 648                 err = 0;
 649         return err;
 650 }
 651
 652 struct tty_driver *register_lines(struct line_driver *line_driver,
 653                                   const struct tty_operations *ops,
 654                                   struct line *lines, int nlines)
 655 {
 656         int i;
 657         struct tty_driver *driver = alloc_tty_driver(nlines);
 658
 659         if (!driver)
 660                 return NULL;
 661
 662         driver->driver_name = line_driver->name;
 663         driver->name = line_driver->device_name;
 664         driver->major = line_driver->major;
 665         driver->minor_start = line_driver->minor_start;
 666         driver->type = line_driver->type;
 667         driver->subtype = line_driver->subtype;
 668         driver->flags = TTY_DRIVER_REAL_RAW;
 669         driver->init_termios = tty_std_termios;
 670         tty_set_operations(driver, ops);
 671
 672         if (tty_register_driver(driver)) {
 673                 printk(KERN_ERR "register_lines : can't register %s driver\n",
 674                        line_driver->name);
 675                 put_tty_driver(driver);
 676                 return NULL;
 677         }
 678
 679         for(i = 0; i < nlines; i++) {
 680                 if (!lines[i].valid)
 681                         tty_unregister_device(driver, i);
 682         }
 683
 684         mconsole_register_dev(&line_driver->mc);
 685         return driver;
 686 }
 687
 688 static DEFINE_SPINLOCK(winch_handler_lock);
 689 static LIST_HEAD(winch_handlers);
 690
 691 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 692 {
 693         struct line *line;
 694         char *error;
 695         int i;
 696
 697         for(i = 0; i < nlines; i++) {
 698                 line = &lines[i];
 699                 INIT_LIST_HEAD(&line->chan_list);
 700
 701                 if (line->init_str == NULL)
 702                         continue;
 703
 704                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
 705                 if (line->init_str == NULL)
 706                         printk(KERN_ERR "lines_init - kstrdup returned NULL\n");
 707
 708                 if (parse_chan_pair(line->init_str, line, i, opts, &error)) {
 709                         printk(KERN_ERR "parse_chan_pair failed for "
 710                                "device %d : %s\n", i, error);
 711                         line->valid = 0;
 712                 }
 713         }
 714 }
 715
 716 struct winch {
 717         struct list_head list;
 718         int fd;
 719         int tty_fd;
 720         int pid;
 721         struct tty_struct *tty;
 722         unsigned long stack;
 723 };
 724
 725 static void free_winch(struct winch *winch, int free_irq_ok)
 726 {
 727         list_del(&winch->list);
 728
 729         if (winch->pid != -1)
 730                 os_kill_process(winch->pid, 1);
 731         if (winch->fd != -1)
 732                 os_close_file(winch->fd);
 733         if (winch->stack != 0)
 734                 free_stack(winch->stack, 0);
 735         if (free_irq_ok)
 736                 free_irq(WINCH_IRQ, winch);
 737         kfree(winch);
 738 }
 739
 740 static irqreturn_t winch_interrupt(int irq, void *data)
 741 {
 742         struct winch *winch = data;
 743         struct tty_struct *tty;
 744         struct line *line;
 745         int err;
 746         char c;
 747
 748         if (winch->fd != -1) {
 749                 err = generic_read(winch->fd, &c, NULL);
 750                 if (err < 0) {
 751                         if (err != -EAGAIN) {
 752                                 printk(KERN_ERR "winch_interrupt : "
 753                                        "read failed, errno = %d\n", -err);
 754                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
 755                                        "support\n", winch->tty_fd);
 756                                 free_winch(winch, 0);
 757                                 return IRQ_HANDLED;
 758                         }
 759                         goto out;
 760                 }
 761         }
 762         tty = winch->tty;
 763         if (tty != NULL) {
 764                 line = tty->driver_data;
 765                 if (line != NULL) {
 766                         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 767                                          &tty->winsize.ws_col);
 768                         kill_pgrp(tty->pgrp, SIGWINCH, 1);
 769                 }
 770         }
 771  out:
 772         if (winch->fd != -1)
 773                 reactivate_fd(winch->fd, WINCH_IRQ);
 774         return IRQ_HANDLED;
 775 }
 776
 777 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
 778                         unsigned long stack)
 779 {
 780         struct winch *winch;
 781
 782         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 783         if (winch == NULL) {
 784                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
 785                 goto cleanup;
 786         }
 787
 788         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 789                                    .fd          = fd,
 790                                    .tty_fd      = tty_fd,
 791                                    .pid         = pid,
 792                                    .tty         = tty,
 793                                    .stack       = stack });
 794
 795         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 796                            IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 797                            "winch", winch) < 0) {
 798                 printk(KERN_ERR "register_winch_irq - failed to register "
 799                        "IRQ\n");
 800                 goto out_free;
 801         }
 802
 803         spin_lock(&winch_handler_lock);
 804         list_add(&winch->list, &winch_handlers);
 805         spin_unlock(&winch_handler_lock);
 806
 807         return;
 808
 809  out_free:
 810         kfree(winch);
 811  cleanup:
 812         os_kill_process(pid, 1);
 813         os_close_file(fd);
 814         if (stack != 0)
 815                 free_stack(stack, 0);
 816 }
 817
 818 static void unregister_winch(struct tty_struct *tty)
 819 {
 820         struct list_head *ele;
 821         struct winch *winch;
 822
 823         spin_lock(&winch_handler_lock);
 824
 825         list_for_each(ele, &winch_handlers) {
 826                 winch = list_entry(ele, struct winch, list);
 827                 if (winch->tty == tty) {
 828                         free_winch(winch, 1);
 829                         break;
 830                 }
 831         }
 832         spin_unlock(&winch_handler_lock);
 833 }
 834
 835 static void winch_cleanup(void)
 836 {
 837         struct list_head *ele, *next;
 838         struct winch *winch;
 839
 840         spin_lock(&winch_handler_lock);
 841
 842         list_for_each_safe(ele, next, &winch_handlers) {
 843                 winch = list_entry(ele, struct winch, list);
 844                 free_winch(winch, 1);
 845         }
 846
 847         spin_unlock(&winch_handler_lock);
 848 }
 849 __uml_exitcall(winch_cleanup);
 850
 851 char *add_xterm_umid(char *base)
 852 {
 853         char *umid, *title;
 854         int len;
 855
 856         umid = get_umid();
 857         if (*umid == '\0')
 858                 return base;
 859
 860         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 861         title = kmalloc(len, GFP_KERNEL);
 862         if (title == NULL) {
 863                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
 864                 return base;
 865         }
 866
 867         snprintf(title, len, "%s (%s)", base, umid);
 868         return title;
 869 }