git.oblomov.eu Git - 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/sched.h"
   7 #include "linux/slab.h"
   8 #include "linux/list.h"
   9 #include "linux/kd.h"
  10 #include "linux/interrupt.h"
  11 #include "asm/uaccess.h"
  12 #include "chan_kern.h"
  13 #include "irq_user.h"
  14 #include "line.h"
  15 #include "kern.h"
  16 #include "user_util.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, err, 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                 err = flush_buffer(line);
 228                 if (err <= 0 && (err != -EAGAIN || !ret))
 229                         ret = err;
 230         } else {
 231                 n = write_chan(&line->chan_list, buf, len,
 232                                line->driver->write_irq);
 233                 if (n < 0) {
 234                         ret = n;
 235                         goto out_up;
 236                 }
 237
 238                 len -= n;
 239                 ret += n;
 240                 if (len > 0)
 241                         ret += buffer_data(line, buf + n, len);
 242         }
 243 out_up:
 244         spin_unlock_irqrestore(&line->lock, flags);
 245         return ret;
 246 }
 247
 248 void line_set_termios(struct tty_struct *tty, struct ktermios * old)
 249 {
 250         /* nothing */
 251 }
 252
 253 static const struct {
 254         int  cmd;
 255         char *level;
 256         char *name;
 257 } tty_ioctls[] = {
 258         /* don't print these, they flood the log ... */
 259         { TCGETS,      NULL,       "TCGETS"      },
 260         { TCSETS,      NULL,       "TCSETS"      },
 261         { TCSETSW,     NULL,       "TCSETSW"     },
 262         { TCFLSH,      NULL,       "TCFLSH"      },
 263         { TCSBRK,      NULL,       "TCSBRK"      },
 264
 265         /* general tty stuff */
 266         { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
 267         { TCGETA,      KERN_DEBUG, "TCGETA"      },
 268         { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
 269         { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
 270         { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
 271
 272         /* linux-specific ones */
 273         { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
 274         { KDGKBMODE,   KERN_INFO,  "KDGKBMODE"   },
 275         { KDGKBTYPE,   KERN_INFO,  "KDGKBTYPE"   },
 276         { KDSIGACCEPT, KERN_INFO,  "KDSIGACCEPT" },
 277 };
 278
 279 int line_ioctl(struct tty_struct *tty, struct file * file,
 280                unsigned int cmd, unsigned long arg)
 281 {
 282         int ret;
 283         int i;
 284
 285         ret = 0;
 286         switch(cmd) {
 287 #ifdef TIOCGETP
 288         case TIOCGETP:
 289         case TIOCSETP:
 290         case TIOCSETN:
 291 #endif
 292 #ifdef TIOCGETC
 293         case TIOCGETC:
 294         case TIOCSETC:
 295 #endif
 296 #ifdef TIOCGLTC
 297         case TIOCGLTC:
 298         case TIOCSLTC:
 299 #endif
 300         case TCGETS:
 301         case TCSETSF:
 302         case TCSETSW:
 303         case TCSETS:
 304         case TCGETA:
 305         case TCSETAF:
 306         case TCSETAW:
 307         case TCSETA:
 308         case TCXONC:
 309         case TCFLSH:
 310         case TIOCOUTQ:
 311         case TIOCINQ:
 312         case TIOCGLCKTRMIOS:
 313         case TIOCSLCKTRMIOS:
 314         case TIOCPKT:
 315         case TIOCGSOFTCAR:
 316         case TIOCSSOFTCAR:
 317                 return -ENOIOCTLCMD;
 318 #if 0
 319         case TCwhatever:
 320                 /* do something */
 321                 break;
 322 #endif
 323         default:
 324                 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
 325                         if (cmd == tty_ioctls[i].cmd)
 326                                 break;
 327                 if (i < ARRAY_SIZE(tty_ioctls)) {
 328                         if (NULL != tty_ioctls[i].level)
 329                                 printk("%s%s: %s: ioctl %s called\n",
 330                                        tty_ioctls[i].level, __FUNCTION__,
 331                                        tty->name, tty_ioctls[i].name);
 332                 } else {
 333                         printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
 334                                __FUNCTION__, tty->name, cmd);
 335                 }
 336                 ret = -ENOIOCTLCMD;
 337                 break;
 338         }
 339         return ret;
 340 }
 341
 342 void line_throttle(struct tty_struct *tty)
 343 {
 344         struct line *line = tty->driver_data;
 345
 346         deactivate_chan(&line->chan_list, line->driver->read_irq);
 347         line->throttled = 1;
 348 }
 349
 350 void line_unthrottle(struct tty_struct *tty)
 351 {
 352         struct line *line = tty->driver_data;
 353
 354         line->throttled = 0;
 355         chan_interrupt(&line->chan_list, &line->task, tty,
 356                        line->driver->read_irq);
 357
 358         /* Maybe there is enough stuff pending that calling the interrupt
 359          * throttles us again.  In this case, line->throttled will be 1
 360          * again and we shouldn't turn the interrupt back on.
 361          */
 362         if(!line->throttled)
 363                 reactivate_chan(&line->chan_list, line->driver->read_irq);
 364 }
 365
 366 static irqreturn_t line_write_interrupt(int irq, void *data)
 367 {
 368         struct chan *chan = data;
 369         struct line *line = chan->line;
 370         struct tty_struct *tty = line->tty;
 371         int err;
 372
 373         /* Interrupts are enabled here because we registered the interrupt with
 374          * IRQF_DISABLED (see line_setup_irq).*/
 375
 376         spin_lock_irq(&line->lock);
 377         err = flush_buffer(line);
 378         if (err == 0) {
 379                 return IRQ_NONE;
 380         } else if(err < 0) {
 381                 line->head = line->buffer;
 382                 line->tail = line->buffer;
 383         }
 384         spin_unlock_irq(&line->lock);
 385
 386         if(tty == NULL)
 387                 return IRQ_NONE;
 388
 389         if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
 390            (tty->ldisc.write_wakeup != NULL))
 391                 (tty->ldisc.write_wakeup)(tty);
 392
 393         /* BLOCKING mode
 394          * In blocking mode, everything sleeps on tty->write_wait.
 395          * Sleeping in the console driver would break non-blocking
 396          * writes.
 397          */
 398
 399         if (waitqueue_active(&tty->write_wait))
 400                 wake_up_interruptible(&tty->write_wait);
 401         return IRQ_HANDLED;
 402 }
 403
 404 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 405 {
 406         const struct line_driver *driver = line->driver;
 407         int err = 0, flags = IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM;
 408
 409         if (input)
 410                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 411                                        line_interrupt, flags,
 412                                        driver->read_irq_name, data);
 413         if (err)
 414                 return err;
 415         if (output)
 416                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 417                                         line_write_interrupt, flags,
 418                                         driver->write_irq_name, data);
 419         line->have_irq = 1;
 420         return err;
 421 }
 422
 423 /* Normally, a driver like this can rely mostly on the tty layer
 424  * locking, particularly when it comes to the driver structure.
 425  * However, in this case, mconsole requests can come in "from the
 426  * side", and race with opens and closes.
 427  *
 428  * mconsole config requests will want to be sure the device isn't in
 429  * use, and get_config, open, and close will want a stable
 430  * configuration.  The checking and modification of the configuration
 431  * is done under a spinlock.  Checking whether the device is in use is
 432  * line->tty->count > 1, also under the spinlock.
 433  *
 434  * tty->count serves to decide whether the device should be enabled or
 435  * disabled on the host.  If it's equal to 1, then we are doing the
 436  * first open or last close.  Otherwise, open and close just return.
 437  */
 438
 439 int line_open(struct line *lines, struct tty_struct *tty)
 440 {
 441         struct line *line = &lines[tty->index];
 442         int err = -ENODEV;
 443
 444         spin_lock(&line->count_lock);
 445         if(!line->valid)
 446                 goto out_unlock;
 447
 448         err = 0;
 449         if(tty->count > 1)
 450                 goto out_unlock;
 451
 452         spin_unlock(&line->count_lock);
 453
 454         tty->driver_data = line;
 455         line->tty = tty;
 456
 457         enable_chan(line);
 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 };
 750
 751 static irqreturn_t winch_interrupt(int irq, void *data)
 752 {
 753         struct winch *winch = data;
 754         struct tty_struct *tty;
 755         struct line *line;
 756         int err;
 757         char c;
 758
 759         if(winch->fd != -1){
 760                 err = generic_read(winch->fd, &c, NULL);
 761                 if(err < 0){
 762                         if(err != -EAGAIN){
 763                                 printk("winch_interrupt : read failed, "
 764                                        "errno = %d\n", -err);
 765                                 printk("fd %d is losing SIGWINCH support\n",
 766                                        winch->tty_fd);
 767                                 return IRQ_HANDLED;
 768                         }
 769                         goto out;
 770                 }
 771         }
 772         tty  = winch->tty;
 773         if (tty != NULL) {
 774                 line = tty->driver_data;
 775                 chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 776                                  &tty->winsize.ws_col);
 777                 kill_pgrp(tty->pgrp, SIGWINCH, 1);
 778         }
 779  out:
 780         if(winch->fd != -1)
 781                 reactivate_fd(winch->fd, WINCH_IRQ);
 782         return IRQ_HANDLED;
 783 }
 784
 785 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
 786 {
 787         struct winch *winch;
 788
 789         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 790         if (winch == NULL) {
 791                 printk("register_winch_irq - kmalloc failed\n");
 792                 return;
 793         }
 794
 795         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 796                                    .fd          = fd,
 797                                    .tty_fd      = tty_fd,
 798                                    .pid         = pid,
 799                                    .tty         = tty });
 800
 801         spin_lock(&winch_handler_lock);
 802         list_add(&winch->list, &winch_handlers);
 803         spin_unlock(&winch_handler_lock);
 804
 805         if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 806                           IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 807                           "winch", winch) < 0)
 808                 printk("register_winch_irq - failed to register IRQ\n");
 809 }
 810
 811 static void free_winch(struct winch *winch)
 812 {
 813         list_del(&winch->list);
 814
 815         if(winch->pid != -1)
 816                 os_kill_process(winch->pid, 1);
 817         if(winch->fd != -1)
 818                 os_close_file(winch->fd);
 819
 820         free_irq(WINCH_IRQ, winch);
 821         kfree(winch);
 822 }
 823
 824 static void unregister_winch(struct tty_struct *tty)
 825 {
 826         struct list_head *ele;
 827         struct winch *winch;
 828
 829         spin_lock(&winch_handler_lock);
 830
 831         list_for_each(ele, &winch_handlers){
 832                 winch = list_entry(ele, struct winch, list);
 833                 if(winch->tty == tty){
 834                         free_winch(winch);
 835                         break;
 836                 }
 837         }
 838         spin_unlock(&winch_handler_lock);
 839 }
 840
 841 static void winch_cleanup(void)
 842 {
 843         struct list_head *ele, *next;
 844         struct winch *winch;
 845
 846         spin_lock(&winch_handler_lock);
 847
 848         list_for_each_safe(ele, next, &winch_handlers){
 849                 winch = list_entry(ele, struct winch, list);
 850                 free_winch(winch);
 851         }
 852
 853         spin_unlock(&winch_handler_lock);
 854 }
 855 __uml_exitcall(winch_cleanup);
 856
 857 char *add_xterm_umid(char *base)
 858 {
 859         char *umid, *title;
 860         int len;
 861
 862         umid = get_umid();
 863         if(*umid == '\0')
 864                 return base;
 865
 866         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 867         title = kmalloc(len, GFP_KERNEL);
 868         if(title == NULL){
 869                 printk("Failed to allocate buffer for xterm title\n");
 870                 return base;
 871         }
 872
 873         snprintf(title, len, "%s (%s)", base, umid);
 874         return title;
 875 }