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