SAFE public projects git trees. - safe/jmp/linux-2.6/blob - arch/um/drivers/line.c

   1 /*
   2  * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/kernel.h"
   7 #include "linux/sched.h"
   8 #include "linux/slab.h"
   9 #include "linux/list.h"
  10 #include "linux/kd.h"
  11 #include "linux/interrupt.h"
  12 #include "asm/uaccess.h"
  13 #include "chan_kern.h"
  14 #include "irq_user.h"
  15 #include "line.h"
  16 #include "kern.h"
  17 #include "kern_util.h"
  18 #include "os.h"
  19 #include "irq_kern.h"
  20
  21 #define LINE_BUFSIZE 4096
  22
  23 static irqreturn_t line_interrupt(int irq, void *data)
  24 {
  25         struct chan *chan = data;
  26         struct line *line = chan->line;
  27         struct tty_struct *tty = line->tty;
  28
  29         if (line)
  30                 chan_interrupt(&line->chan_list, &line->task, tty, irq);
  31         return IRQ_HANDLED;
  32 }
  33
  34 static void line_timer_cb(struct work_struct *work)
  35 {
  36         struct line *line = container_of(work, struct line, task.work);
  37
  38         if(!line->throttled)
  39                 chan_interrupt(&line->chan_list, &line->task, line->tty,
  40                                line->driver->read_irq);
  41 }
  42
  43 /* Returns the free space inside the ring buffer of this line.
  44  *
  45  * Should be called while holding line->lock (this does not modify datas).
  46  */
  47 static int write_room(struct line *line)
  48 {
  49         int n;
  50
  51         if (line->buffer == NULL)
  52                 return LINE_BUFSIZE - 1;
  53
  54         /* This is for the case where the buffer is wrapped! */
  55         n = line->head - line->tail;
  56
  57         if (n <= 0)
  58                 n = LINE_BUFSIZE + n; /* The other case */
  59         return n - 1;
  60 }
  61
  62 int line_write_room(struct tty_struct *tty)
  63 {
  64         struct line *line = tty->driver_data;
  65         unsigned long flags;
  66         int room;
  67
  68         if (tty->stopped)
  69                 return 0;
  70
  71         spin_lock_irqsave(&line->lock, flags);
  72         room = write_room(line);
  73         spin_unlock_irqrestore(&line->lock, flags);
  74
  75         /*XXX: Warning to remove */
  76         if (0 == room)
  77                 printk(KERN_DEBUG "%s: %s: no room left in buffer\n",
  78                        __FUNCTION__,tty->name);
  79         return room;
  80 }
  81
  82 int line_chars_in_buffer(struct tty_struct *tty)
  83 {
  84         struct line *line = tty->driver_data;
  85         unsigned long flags;
  86         int ret;
  87
  88         spin_lock_irqsave(&line->lock, flags);
  89
  90         /*write_room subtracts 1 for the needed NULL, so we readd it.*/
  91         ret = LINE_BUFSIZE - (write_room(line) + 1);
  92         spin_unlock_irqrestore(&line->lock, flags);
  93
  94         return ret;
  95 }
  96
  97 /*
  98  * This copies the content of buf into the circular buffer associated with
  99  * this line.
 100  * The return value is the number of characters actually copied, i.e. the ones
 101  * for which there was space: this function is not supposed to ever flush out
 102  * the circular buffer.
 103  *
 104  * Must be called while holding line->lock!
 105  */
 106 static int buffer_data(struct line *line, const char *buf, int len)
 107 {
 108         int end, room;
 109
 110         if(line->buffer == NULL){
 111                 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
 112                 if (line->buffer == NULL) {
 113                         printk("buffer_data - atomic allocation failed\n");
 114                         return(0);
 115                 }
 116                 line->head = line->buffer;
 117                 line->tail = line->buffer;
 118         }
 119
 120         room = write_room(line);
 121         len = (len > room) ? room : len;
 122
 123         end = line->buffer + LINE_BUFSIZE - line->tail;
 124
 125         if (len < end){
 126                 memcpy(line->tail, buf, len);
 127                 line->tail += len;
 128         }
 129         else {
 130                 /* The circular buffer is wrapping */
 131                 memcpy(line->tail, buf, end);
 132                 buf += end;
 133                 memcpy(line->buffer, buf, len - end);
 134                 line->tail = line->buffer + len - end;
 135         }
 136
 137         return len;
 138 }
 139
 140 /*
 141  * Flushes the ring buffer to the output channels. That is, write_chan is
 142  * called, passing it line->head as buffer, and an appropriate count.
 143  *
 144  * On exit, returns 1 when the buffer is empty,
 145  * 0 when the buffer is not empty on exit,
 146  * and -errno when an error occurred.
 147  *
 148  * Must be called while holding line->lock!*/
 149 static int flush_buffer(struct line *line)
 150 {
 151         int n, count;
 152
 153         if ((line->buffer == NULL) || (line->head == line->tail))
 154                 return 1;
 155
 156         if (line->tail < line->head) {
 157                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
 158                 count = line->buffer + LINE_BUFSIZE - line->head;
 159
 160                 n = write_chan(&line->chan_list, line->head, count,
 161                                line->driver->write_irq);
 162                 if (n < 0)
 163                         return n;
 164                 if (n == count) {
 165                         /* We have flushed from ->head to buffer end, now we
 166                          * must flush only from the beginning to ->tail.*/
 167                         line->head = line->buffer;
 168                 } else {
 169                         line->head += n;
 170                         return 0;
 171                 }
 172         }
 173
 174         count = line->tail - line->head;
 175         n = write_chan(&line->chan_list, line->head, count,
 176                        line->driver->write_irq);
 177
 178         if(n < 0)
 179                 return n;
 180
 181         line->head += n;
 182         return line->head == line->tail;
 183 }
 184
 185 void line_flush_buffer(struct tty_struct *tty)
 186 {
 187         struct line *line = tty->driver_data;
 188         unsigned long flags;
 189         int err;
 190
 191         /*XXX: copied from line_write, verify if it is correct!*/
 192         if(tty->stopped)
 193                 return;
 194
 195         spin_lock_irqsave(&line->lock, flags);
 196         err = flush_buffer(line);
 197         /*if (err == 1)
 198                 err = 0;*/
 199         spin_unlock_irqrestore(&line->lock, flags);
 200         //return err;
 201 }
 202
 203 /* We map both ->flush_chars and ->put_char (which go in pair) onto ->flush_buffer
 204  * and ->write. Hope it's not that bad.*/
 205 void line_flush_chars(struct tty_struct *tty)
 206 {
 207         line_flush_buffer(tty);
 208 }
 209
 210 void line_put_char(struct tty_struct *tty, unsigned char ch)
 211 {
 212         line_write(tty, &ch, sizeof(ch));
 213 }
 214
 215 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
 216 {
 217         struct line *line = tty->driver_data;
 218         unsigned long flags;
 219         int n, ret = 0;
 220
 221         if(tty->stopped)
 222                 return 0;
 223
 224         spin_lock_irqsave(&line->lock, flags);
 225         if (line->head != line->tail)
 226                 ret = buffer_data(line, buf, len);
 227         else {
 228                 n = write_chan(&line->chan_list, buf, len,
 229                                line->driver->write_irq);
 230                 if (n < 0) {
 231                         ret = n;
 232                         goto out_up;
 233                 }
 234
 235                 len -= n;
 236                 ret += n;
 237                 if (len > 0)
 238                         ret += buffer_data(line, buf + n, len);
 239         }
 240 out_up:
 241         spin_unlock_irqrestore(&line->lock, flags);
 242         return ret;
 243 }
 244
 245 void line_set_termios(struct tty_struct *tty, struct ktermios * old)
 246 {
 247         /* nothing */
 248 }
 249
 250 static const struct {
 251         int  cmd;
 252         char *level;
 253         char *name;
 254 } tty_ioctls[] = {
 255         /* don't print these, they flood the log ... */
 256         { TCGETS,      NULL,       "TCGETS"      },
 257         { TCSETS,      NULL,       "TCSETS"      },
 258         { TCSETSW,     NULL,       "TCSETSW"     },
 259         { TCFLSH,      NULL,       "TCFLSH"      },
 260         { TCSBRK,      NULL,       "TCSBRK"      },
 261
 262         /* general tty stuff */
 263         { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
 264         { TCGETA,      KERN_DEBUG, "TCGETA"      },
 265         { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
 266         { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
 267         { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
 268
 269         /* linux-specific ones */
 270         { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
 271         { KDGKBMODE,   KERN_INFO,  "KDGKBMODE"   },
 272         { KDGKBTYPE,   KERN_INFO,  "KDGKBTYPE"   },
 273         { KDSIGACCEPT, KERN_INFO,  "KDSIGACCEPT" },
 274 };
 275
 276 int line_ioctl(struct tty_struct *tty, struct file * file,
 277                unsigned int cmd, unsigned long arg)
 278 {
 279         int ret;
 280         int i;
 281
 282         ret = 0;
 283         switch(cmd) {
 284 #ifdef TIOCGETP
 285         case TIOCGETP:
 286         case TIOCSETP:
 287         case TIOCSETN:
 288 #endif
 289 #ifdef TIOCGETC
 290         case TIOCGETC:
 291         case TIOCSETC:
 292 #endif
 293 #ifdef TIOCGLTC
 294         case TIOCGLTC:
 295         case TIOCSLTC:
 296 #endif
 297         case TCGETS:
 298         case TCSETSF:
 299         case TCSETSW:
 300         case TCSETS:
 301         case TCGETA:
 302         case TCSETAF:
 303         case TCSETAW:
 304         case TCSETA:
 305         case TCXONC:
 306         case TCFLSH:
 307         case TIOCOUTQ:
 308         case TIOCINQ:
 309         case TIOCGLCKTRMIOS:
 310         case TIOCSLCKTRMIOS:
 311         case TIOCPKT:
 312         case TIOCGSOFTCAR:
 313         case TIOCSSOFTCAR:
 314                 return -ENOIOCTLCMD;
 315 #if 0
 316         case TCwhatever:
 317                 /* do something */
 318                 break;
 319 #endif
 320         default:
 321                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
 322                         if (cmd == tty_ioctls[i].cmd)
 323                                 break;
 324                 if (i < ARRAY_SIZE(tty_ioctls)) {
 325                         if (NULL != tty_ioctls[i].level)
 326                                 printk("%s%s: %s: ioctl %s called\n",
 327                                        tty_ioctls[i].level, __FUNCTION__,
 328                                        tty->name, tty_ioctls[i].name);
 329                 } else {
 330                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
 331                                __FUNCTION__, tty->name, cmd);
 332                 }
 333                 ret = -ENOIOCTLCMD;
 334                 break;
 335         }
 336         return ret;
 337 }
 338
 339 void line_throttle(struct tty_struct *tty)
 340 {
 341         struct line *line = tty->driver_data;
 342
 343         deactivate_chan(&line->chan_list, line->driver->read_irq);
 344         line->throttled = 1;
 345 }
 346
 347 void line_unthrottle(struct tty_struct *tty)
 348 {
 349         struct line *line = tty->driver_data;
 350
 351         line->throttled = 0;
 352         chan_interrupt(&line->chan_list, &line->task, tty,
 353                        line->driver->read_irq);
 354
 355         /* Maybe there is enough stuff pending that calling the interrupt
 356          * throttles us again.  In this case, line->throttled will be 1
 357          * again and we shouldn't turn the interrupt back on.
 358          */
 359         if(!line->throttled)
 360                 reactivate_chan(&line->chan_list, line->driver->read_irq);
 361 }
 362
 363 static irqreturn_t line_write_interrupt(int irq, void *data)
 364 {
 365         struct chan *chan = data;
 366         struct line *line = chan->line;
 367         struct tty_struct *tty = line->tty;
 368         int err;
 369
 370         /* Interrupts are disabled here because we registered the interrupt with
 371          * IRQF_DISABLED (see line_setup_irq).*/
 372
 373         spin_lock(&line->lock);
 374         err = flush_buffer(line);
 375         if (err == 0) {
 376                 return IRQ_NONE;
 377         } else if(err < 0) {
 378                 line->head = line->buffer;
 379                 line->tail = line->buffer;
 380         }
 381         spin_unlock(&line->lock);
 382
 383         if(tty == NULL)
 384                 return IRQ_NONE;
 385
 386         if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
 387            (tty->ldisc.write_wakeup != NULL))
 388                 (tty->ldisc.write_wakeup)(tty);
 389
 390         /* BLOCKING mode
 391          * In blocking mode, everything sleeps on tty->write_wait.
 392          * Sleeping in the console driver would break non-blocking
 393          * writes.
 394          */
 395
 396         if (waitqueue_active(&tty->write_wait))
 397                 wake_up_interruptible(&tty->write_wait);
 398         return IRQ_HANDLED;
 399 }
 400
 401 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 402 {
 403         const struct line_driver *driver = line->driver;
 404         int err = 0, flags = IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM;
 405
 406         if (input)
 407                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 408                                        line_interrupt, flags,
 409                                        driver->read_irq_name, data);
 410         if (err)
 411                 return err;
 412         if (output)
 413                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 414                                         line_write_interrupt, flags,
 415                                         driver->write_irq_name, data);
 416         line->have_irq = 1;
 417         return err;
 418 }
 419
 420 /* Normally, a driver like this can rely mostly on the tty layer
 421  * locking, particularly when it comes to the driver structure.
 422  * However, in this case, mconsole requests can come in "from the
 423  * side", and race with opens and closes.
 424  *
 425  * mconsole config requests will want to be sure the device isn't in
 426  * use, and get_config, open, and close will want a stable
 427  * configuration.  The checking and modification of the configuration
 428  * is done under a spinlock.  Checking whether the device is in use is
 429  * line->tty->count > 1, also under the spinlock.
 430  *
 431  * tty->count serves to decide whether the device should be enabled or
 432  * disabled on the host.  If it's equal to 1, then we are doing the
 433  * first open or last close.  Otherwise, open and close just return.
 434  */
 435
 436 int line_open(struct line *lines, struct tty_struct *tty)
 437 {
 438         struct line *line = &lines[tty->index];
 439         int err = -ENODEV;
 440
 441         spin_lock(&line->count_lock);
 442         if(!line->valid)
 443                 goto out_unlock;
 444
 445         err = 0;
 446         if(tty->count > 1)
 447                 goto out_unlock;
 448
 449         spin_unlock(&line->count_lock);
 450
 451         tty->driver_data = line;
 452         line->tty = tty;
 453
 454         err = enable_chan(line);
 455         if (err)
 456                 return err;
 457
 458         INIT_DELAYED_WORK(&line->task, line_timer_cb);
 459
 460         if(!line->sigio){
 461                 chan_enable_winch(&line->chan_list, tty);
 462                 line->sigio = 1;
 463         }
 464
 465         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 466                          &tty->winsize.ws_col);
 467
 468         return err;
 469
 470 out_unlock:
 471         spin_unlock(&line->count_lock);
 472         return err;
 473 }
 474
 475 static void unregister_winch(struct tty_struct *tty);
 476
 477 void line_close(struct tty_struct *tty, struct file * filp)
 478 {
 479         struct line *line = tty->driver_data;
 480
 481         /* If line_open fails (and tty->driver_data is never set),
 482          * tty_open will call line_close.  So just return in this case.
 483          */
 484         if(line == NULL)
 485                 return;
 486
 487         /* We ignore the error anyway! */
 488         flush_buffer(line);
 489
 490         spin_lock(&line->count_lock);
 491         if(!line->valid)
 492                 goto out_unlock;
 493
 494         if(tty->count > 1)
 495                 goto out_unlock;
 496
 497         spin_unlock(&line->count_lock);
 498
 499         line->tty = NULL;
 500         tty->driver_data = NULL;
 501
 502         if(line->sigio){
 503                 unregister_winch(tty);
 504                 line->sigio = 0;
 505         }
 506
 507         return;
 508
 509 out_unlock:
 510         spin_unlock(&line->count_lock);
 511 }
 512
 513 void close_lines(struct line *lines, int nlines)
 514 {
 515         int i;
 516
 517         for(i = 0; i < nlines; i++)
 518                 close_chan(&lines[i].chan_list, 0);
 519 }
 520
 521 static int setup_one_line(struct line *lines, int n, char *init, int init_prio,
 522                           char **error_out)
 523 {
 524         struct line *line = &lines[n];
 525         int err = -EINVAL;
 526
 527         spin_lock(&line->count_lock);
 528
 529         if(line->tty != NULL){
 530                 *error_out = "Device is already open";
 531                 goto out;
 532         }
 533
 534         if (line->init_pri <= init_prio){
 535                 line->init_pri = init_prio;
 536                 if (!strcmp(init, "none"))
 537                         line->valid = 0;
 538                 else {
 539                         line->init_str = init;
 540                         line->valid = 1;
 541                 }
 542         }
 543         err = 0;
 544 out:
 545         spin_unlock(&line->count_lock);
 546         return err;
 547 }
 548
 549 /* Common setup code for both startup command line and mconsole initialization.
 550  * @lines contains the array (of size @num) to modify;
 551  * @init is the setup string;
 552  * @error_out is an error string in the case of failure;
 553  */
 554
 555 int line_setup(struct line *lines, unsigned int num, char *init,
 556                char **error_out)
 557 {
 558         int i, n, err;
 559         char *end;
 560
 561         if(*init == '=') {
 562                 /* We said con=/ssl= instead of con#=, so we are configuring all
 563                  * consoles at once.*/
 564                 n = -1;
 565         }
 566         else {
 567                 n = simple_strtoul(init, &end, 0);
 568                 if(*end != '='){
 569                         *error_out = "Couldn't parse device number";
 570                         return -EINVAL;
 571                 }
 572                 init = end;
 573         }
 574         init++;
 575
 576         if (n >= (signed int) num) {
 577                 *error_out = "Device number out of range";
 578                 return -EINVAL;
 579         }
 580         else if (n >= 0){
 581                 err = setup_one_line(lines, n, init, INIT_ONE, error_out);
 582                 if(err)
 583                         return err;
 584         }
 585         else {
 586                 for(i = 0; i < num; i++){
 587                         err = setup_one_line(lines, i, init, INIT_ALL,
 588                                              error_out);
 589                         if(err)
 590                                 return err;
 591                 }
 592         }
 593         return n == -1 ? num : n;
 594 }
 595
 596 int line_config(struct line *lines, unsigned int num, char *str,
 597                 const struct chan_opts *opts, char **error_out)
 598 {
 599         struct line *line;
 600         char *new;
 601         int n;
 602
 603         if(*str == '='){
 604                 *error_out = "Can't configure all devices from mconsole";
 605                 return -EINVAL;
 606         }
 607
 608         new = kstrdup(str, GFP_KERNEL);
 609         if(new == NULL){
 610                 *error_out = "Failed to allocate memory";
 611                 return -ENOMEM;
 612         }
 613         n = line_setup(lines, num, new, error_out);
 614         if(n < 0)
 615                 return n;
 616
 617         line = &lines[n];
 618         return parse_chan_pair(line->init_str, line, n, opts, error_out);
 619 }
 620
 621 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 622                     int size, char **error_out)
 623 {
 624         struct line *line;
 625         char *end;
 626         int dev, n = 0;
 627
 628         dev = simple_strtoul(name, &end, 0);
 629         if((*end != '\0') || (end == name)){
 630                 *error_out = "line_get_config failed to parse device number";
 631                 return 0;
 632         }
 633
 634         if((dev < 0) || (dev >= num)){
 635                 *error_out = "device number out of range";
 636                 return 0;
 637         }
 638
 639         line = &lines[dev];
 640
 641         spin_lock(&line->count_lock);
 642         if(!line->valid)
 643                 CONFIG_CHUNK(str, size, n, "none", 1);
 644         else if(line->tty == NULL)
 645                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 646         else n = chan_config_string(&line->chan_list, str, size, error_out);
 647         spin_unlock(&line->count_lock);
 648
 649         return n;
 650 }
 651
 652 int line_id(char **str, int *start_out, int *end_out)
 653 {
 654         char *end;
 655         int n;
 656
 657         n = simple_strtoul(*str, &end, 0);
 658         if((*end != '\0') || (end == *str))
 659                 return -1;
 660
 661         *str = end;
 662         *start_out = n;
 663         *end_out = n;
 664         return n;
 665 }
 666
 667 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 668 {
 669         int err;
 670         char config[sizeof("conxxxx=none\0")];
 671
 672         sprintf(config, "%d=none", n);
 673         err = line_setup(lines, num, config, error_out);
 674         if(err >= 0)
 675                 err = 0;
 676         return err;
 677 }
 678
 679 struct tty_driver *register_lines(struct line_driver *line_driver,
 680                                   const struct tty_operations *ops,
 681                                   struct line *lines, int nlines)
 682 {
 683         int i;
 684         struct tty_driver *driver = alloc_tty_driver(nlines);
 685
 686         if (!driver)
 687                 return NULL;
 688
 689         driver->driver_name = line_driver->name;
 690         driver->name = line_driver->device_name;
 691         driver->major = line_driver->major;
 692         driver->minor_start = line_driver->minor_start;
 693         driver->type = line_driver->type;
 694         driver->subtype = line_driver->subtype;
 695         driver->flags = TTY_DRIVER_REAL_RAW;
 696         driver->init_termios = tty_std_termios;
 697         tty_set_operations(driver, ops);
 698
 699         if (tty_register_driver(driver)) {
 700                 printk("%s: can't register %s driver\n",
 701                        __FUNCTION__,line_driver->name);
 702                 put_tty_driver(driver);
 703                 return NULL;
 704         }
 705
 706         for(i = 0; i < nlines; i++){
 707                 if(!lines[i].valid)
 708                         tty_unregister_device(driver, i);
 709         }
 710
 711         mconsole_register_dev(&line_driver->mc);
 712         return driver;
 713 }
 714
 715 static DEFINE_SPINLOCK(winch_handler_lock);
 716 static LIST_HEAD(winch_handlers);
 717
 718 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 719 {
 720         struct line *line;
 721         char *error;
 722         int i;
 723
 724         for(i = 0; i < nlines; i++){
 725                 line = &lines[i];
 726                 INIT_LIST_HEAD(&line->chan_list);
 727
 728                 if(line->init_str == NULL)
 729                         continue;
 730
 731                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
 732                 if(line->init_str == NULL)
 733                         printk("lines_init - kstrdup returned NULL\n");
 734
 735                 if(parse_chan_pair(line->init_str, line, i, opts, &error)){
 736                         printk("parse_chan_pair failed for device %d : %s\n",
 737                                i, error);
 738                         line->valid = 0;
 739                 }
 740         }
 741 }
 742
 743 struct winch {
 744         struct list_head list;
 745         int fd;
 746         int tty_fd;
 747         int pid;
 748         struct tty_struct *tty;
 749         unsigned long stack;
 750 };
 751
 752 static void free_winch(struct winch *winch, int free_irq_ok)
 753 {
 754         list_del(&winch->list);
 755
 756         if (winch->pid != -1)
 757                 os_kill_process(winch->pid, 1);
 758         if (winch->fd != -1)
 759                 os_close_file(winch->fd);
 760         if (winch->stack != 0)
 761                 free_stack(winch->stack, 0);
 762         if (free_irq_ok)
 763                 free_irq(WINCH_IRQ, winch);
 764         kfree(winch);
 765 }
 766
 767 static irqreturn_t winch_interrupt(int irq, void *data)
 768 {
 769         struct winch *winch = data;
 770         struct tty_struct *tty;
 771         struct line *line;
 772         int err;
 773         char c;
 774
 775         if(winch->fd != -1){
 776                 err = generic_read(winch->fd, &c, NULL);
 777                 if(err < 0){
 778                         if(err != -EAGAIN){
 779                                 printk("winch_interrupt : read failed, "
 780                                        "errno = %d\n", -err);
 781                                 printk("fd %d is losing SIGWINCH support\n",
 782                                        winch->tty_fd);
 783                                 free_winch(winch, 0);
 784                                 return IRQ_HANDLED;
 785                         }
 786                         goto out;
 787                 }
 788         }
 789         tty = winch->tty;
 790         if (tty != NULL) {
 791                 line = tty->driver_data;
 792                 chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 793                                  &tty->winsize.ws_col);
 794                 kill_pgrp(tty->pgrp, SIGWINCH, 1);
 795         }
 796  out:
 797         if(winch->fd != -1)
 798                 reactivate_fd(winch->fd, WINCH_IRQ);
 799         return IRQ_HANDLED;
 800 }
 801
 802 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
 803                         unsigned long stack)
 804 {
 805         struct winch *winch;
 806
 807         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 808         if (winch == NULL) {
 809                 printk("register_winch_irq - kmalloc failed\n");
 810                 goto cleanup;
 811         }
 812
 813         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 814                                    .fd          = fd,
 815                                    .tty_fd      = tty_fd,
 816                                    .pid         = pid,
 817                                    .tty         = tty,
 818                                    .stack       = stack });
 819
 820         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 821                            IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 822                            "winch", winch) < 0) {
 823                 printk("register_winch_irq - failed to register IRQ\n");
 824                 goto out_free;
 825         }
 826
 827         spin_lock(&winch_handler_lock);
 828         list_add(&winch->list, &winch_handlers);
 829         spin_unlock(&winch_handler_lock);
 830
 831         return;
 832
 833  out_free:
 834         kfree(winch);
 835  cleanup:
 836         os_kill_process(pid, 1);
 837         os_close_file(fd);
 838         if (stack != 0)
 839                 free_stack(stack, 0);
 840 }
 841
 842 static void unregister_winch(struct tty_struct *tty)
 843 {
 844         struct list_head *ele;
 845         struct winch *winch;
 846
 847         spin_lock(&winch_handler_lock);
 848
 849         list_for_each(ele, &winch_handlers){
 850                 winch = list_entry(ele, struct winch, list);
 851                 if(winch->tty == tty){
 852                         free_winch(winch, 1);
 853                         break;
 854                 }
 855         }
 856         spin_unlock(&winch_handler_lock);
 857 }
 858
 859 static void winch_cleanup(void)
 860 {
 861         struct list_head *ele, *next;
 862         struct winch *winch;
 863
 864         spin_lock(&winch_handler_lock);
 865
 866         list_for_each_safe(ele, next, &winch_handlers){
 867                 winch = list_entry(ele, struct winch, list);
 868                 free_winch(winch, 1);
 869         }
 870
 871         spin_unlock(&winch_handler_lock);
 872 }
 873 __uml_exitcall(winch_cleanup);
 874
 875 char *add_xterm_umid(char *base)
 876 {
 877         char *umid, *title;
 878         int len;
 879
 880         umid = get_umid();
 881         if(*umid == '\0')
 882                 return base;
 883
 884         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 885         title = kmalloc(len, GFP_KERNEL);
 886         if(title == NULL){
 887                 printk("Failed to allocate buffer for xterm title\n");
 888                 return base;
 889         }
 890
 891         snprintf(title, len, "%s (%s)", base, umid);
 892         return title;
 893 }