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/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  * The problem comes from line_setup not wanting to sleep if
 429  * the device is open or being opened.  This can happen because the
 430  * first opener of a device is responsible for setting it up on the
 431  * host, and that can sleep.  The open of a port device will sleep
 432  * until someone telnets to it.
 433  *
 434  * The obvious solution of putting everything under a mutex fails
 435  * because then trying (and failing) to change the configuration of an
 436  * open(ing) device will block until the open finishes.  The right
 437  * thing to happen is for it to fail immediately.
 438  *
 439  * We can put the opening (and closing) of the host device under a
 440  * separate lock, but that has to be taken before the count lock is
 441  * released.  Otherwise, you open a window in which another open can
 442  * come through and assume that the host side is opened and working.
 443  *
 444  * So, if the tty count is one, open will take the open mutex
 445  * inside the count lock.  Otherwise, it just returns. This will sleep
 446  * if the last close is pending, and will block a setup or get_config,
 447  * but that should not last long.
 448  *
 449  * So, what we end up with is that open and close take the count lock.
 450  * If the first open or last close are happening, then the open mutex
 451  * is taken inside the count lock and the host opening or closing is done.
 452  *
 453  * setup and get_config only take the count lock.  setup modifies the
 454  * device configuration only if the open count is zero.  Arbitrarily
 455  * long blocking of setup doesn't happen because something would have to be
 456  * waiting for an open to happen.  However, a second open with
 457  * tty->count == 1 can't happen, and a close can't happen until the open
 458  * had finished.
 459  *
 460  * We can't maintain our own count here because the tty layer doesn't
 461  * match opens and closes.  It will call close if an open failed, and
 462  * a tty hangup will result in excess closes.  So, we rely on
 463  * tty->count instead.  It is one on both the first open and last close.
 464  */
 465
 466 int line_open(struct line *lines, struct tty_struct *tty)
 467 {
 468         struct line *line = &lines[tty->index];
 469         int err = -ENODEV;
 470
 471         spin_lock(&line->count_lock);
 472         if(!line->valid)
 473                 goto out_unlock;
 474
 475         err = 0;
 476         if(tty->count > 1)
 477                 goto out_unlock;
 478
 479         mutex_lock(&line->open_mutex);
 480         spin_unlock(&line->count_lock);
 481
 482         tty->driver_data = line;
 483         line->tty = tty;
 484
 485         enable_chan(line);
 486         INIT_DELAYED_WORK(&line->task, line_timer_cb);
 487
 488         if(!line->sigio){
 489                 chan_enable_winch(&line->chan_list, tty);
 490                 line->sigio = 1;
 491         }
 492
 493         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 494                          &tty->winsize.ws_col);
 495
 496         mutex_unlock(&line->open_mutex);
 497         return err;
 498
 499 out_unlock:
 500         spin_unlock(&line->count_lock);
 501         return err;
 502 }
 503
 504 static void unregister_winch(struct tty_struct *tty);
 505
 506 void line_close(struct tty_struct *tty, struct file * filp)
 507 {
 508         struct line *line = tty->driver_data;
 509
 510         /* If line_open fails (and tty->driver_data is never set),
 511          * tty_open will call line_close.  So just return in this case.
 512          */
 513         if(line == NULL)
 514                 return;
 515
 516         /* We ignore the error anyway! */
 517         flush_buffer(line);
 518
 519         spin_lock(&line->count_lock);
 520         if(!line->valid)
 521                 goto out_unlock;
 522
 523         if(tty->count > 1)
 524                 goto out_unlock;
 525
 526         mutex_lock(&line->open_mutex);
 527         spin_unlock(&line->count_lock);
 528
 529         line->tty = NULL;
 530         tty->driver_data = NULL;
 531
 532         if(line->sigio){
 533                 unregister_winch(tty);
 534                 line->sigio = 0;
 535         }
 536
 537         mutex_unlock(&line->open_mutex);
 538         return;
 539
 540 out_unlock:
 541         spin_unlock(&line->count_lock);
 542 }
 543
 544 void close_lines(struct line *lines, int nlines)
 545 {
 546         int i;
 547
 548         for(i = 0; i < nlines; i++)
 549                 close_chan(&lines[i].chan_list, 0);
 550 }
 551
 552 static void setup_one_line(struct line *lines, int n, char *init, int init_prio)
 553 {
 554         struct line *line = &lines[n];
 555
 556         spin_lock(&line->count_lock);
 557
 558         if(line->tty != NULL){
 559                 printk("line_setup - device %d is open\n", n);
 560                 goto out;
 561         }
 562
 563         if (line->init_pri <= init_prio){
 564                 line->init_pri = init_prio;
 565                 if (!strcmp(init, "none"))
 566                         line->valid = 0;
 567                 else {
 568                         line->init_str = init;
 569                         line->valid = 1;
 570                 }
 571         }
 572 out:
 573         spin_unlock(&line->count_lock);
 574 }
 575
 576 /* Common setup code for both startup command line and mconsole initialization.
 577  * @lines contains the array (of size @num) to modify;
 578  * @init is the setup string;
 579  */
 580
 581 int line_setup(struct line *lines, unsigned int num, char *init)
 582 {
 583         int i, n;
 584         char *end;
 585
 586         if(*init == '=') {
 587                 /* We said con=/ssl= instead of con#=, so we are configuring all
 588                  * consoles at once.*/
 589                 n = -1;
 590         }
 591         else {
 592                 n = simple_strtoul(init, &end, 0);
 593                 if(*end != '='){
 594                         printk(KERN_ERR "line_setup failed to parse \"%s\"\n",
 595                                init);
 596                         return 0;
 597                 }
 598                 init = end;
 599         }
 600         init++;
 601
 602         if (n >= (signed int) num) {
 603                 printk("line_setup - %d out of range ((0 ... %d) allowed)\n",
 604                        n, num - 1);
 605                 return 0;
 606         }
 607         else if (n >= 0)
 608                 setup_one_line(lines, n, init, INIT_ONE);
 609         else {
 610                 for(i = 0; i < num; i++)
 611                         setup_one_line(lines, i, init, INIT_ALL);
 612         }
 613         return n == -1 ? num : n;
 614 }
 615
 616 int line_config(struct line *lines, unsigned int num, char *str,
 617                 const struct chan_opts *opts)
 618 {
 619         struct line *line;
 620         char *new;
 621         int n;
 622
 623         if(*str == '='){
 624                 printk("line_config - can't configure all devices from "
 625                        "mconsole\n");
 626                 return 1;
 627         }
 628
 629         new = kstrdup(str, GFP_KERNEL);
 630         if(new == NULL){
 631                 printk("line_config - kstrdup failed\n");
 632                 return 1;
 633         }
 634         n = line_setup(lines, num, new);
 635         if(n < 0)
 636                 return 1;
 637
 638         line = &lines[n];
 639         return parse_chan_pair(line->init_str, line, n, opts);
 640 }
 641
 642 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 643                     int size, char **error_out)
 644 {
 645         struct line *line;
 646         char *end;
 647         int dev, n = 0;
 648
 649         dev = simple_strtoul(name, &end, 0);
 650         if((*end != '\0') || (end == name)){
 651                 *error_out = "line_get_config failed to parse device number";
 652                 return 0;
 653         }
 654
 655         if((dev < 0) || (dev >= num)){
 656                 *error_out = "device number out of range";
 657                 return 0;
 658         }
 659
 660         line = &lines[dev];
 661
 662         spin_lock(&line->count_lock);
 663         if(!line->valid)
 664                 CONFIG_CHUNK(str, size, n, "none", 1);
 665         else if(line->tty == NULL)
 666                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 667         else n = chan_config_string(&line->chan_list, str, size, error_out);
 668         spin_unlock(&line->count_lock);
 669
 670         return n;
 671 }
 672
 673 int line_id(char **str, int *start_out, int *end_out)
 674 {
 675         char *end;
 676         int n;
 677
 678         n = simple_strtoul(*str, &end, 0);
 679         if((*end != '\0') || (end == *str))
 680                 return -1;
 681
 682         *str = end;
 683         *start_out = n;
 684         *end_out = n;
 685         return n;
 686 }
 687
 688 int line_remove(struct line *lines, unsigned int num, int n)
 689 {
 690         int err;
 691         char config[sizeof("conxxxx=none\0")];
 692
 693         sprintf(config, "%d=none", n);
 694         err = line_setup(lines, num, config);
 695         if(err >= 0)
 696                 err = 0;
 697         return err;
 698 }
 699
 700 struct tty_driver *line_register_devfs(struct lines *set,
 701                                        struct line_driver *line_driver,
 702                                        const struct tty_operations *ops,
 703                                        struct line *lines, int nlines)
 704 {
 705         int i;
 706         struct tty_driver *driver = alloc_tty_driver(nlines);
 707
 708         if (!driver)
 709                 return NULL;
 710
 711         driver->driver_name = line_driver->name;
 712         driver->name = line_driver->device_name;
 713         driver->major = line_driver->major;
 714         driver->minor_start = line_driver->minor_start;
 715         driver->type = line_driver->type;
 716         driver->subtype = line_driver->subtype;
 717         driver->flags = TTY_DRIVER_REAL_RAW;
 718         driver->init_termios = tty_std_termios;
 719         tty_set_operations(driver, ops);
 720
 721         if (tty_register_driver(driver)) {
 722                 printk("%s: can't register %s driver\n",
 723                        __FUNCTION__,line_driver->name);
 724                 put_tty_driver(driver);
 725                 return NULL;
 726         }
 727
 728         for(i = 0; i < nlines; i++){
 729                 if(!lines[i].valid)
 730                         tty_unregister_device(driver, i);
 731         }
 732
 733         mconsole_register_dev(&line_driver->mc);
 734         return driver;
 735 }
 736
 737 static DEFINE_SPINLOCK(winch_handler_lock);
 738 static LIST_HEAD(winch_handlers);
 739
 740 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 741 {
 742         struct line *line;
 743         int i;
 744
 745         for(i = 0; i < nlines; i++){
 746                 line = &lines[i];
 747                 INIT_LIST_HEAD(&line->chan_list);
 748                 mutex_init(&line->open_mutex);
 749
 750                 if(line->init_str == NULL)
 751                         continue;
 752
 753                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
 754                 if(line->init_str == NULL)
 755                         printk("lines_init - kstrdup returned NULL\n");
 756
 757                 if(parse_chan_pair(line->init_str, line, i, opts)){
 758                         printk("parse_chan_pair failed for device %d\n", i);
 759                         line->valid = 0;
 760                 }
 761         }
 762 }
 763
 764 struct winch {
 765         struct list_head list;
 766         int fd;
 767         int tty_fd;
 768         int pid;
 769         struct tty_struct *tty;
 770 };
 771
 772 static irqreturn_t winch_interrupt(int irq, void *data)
 773 {
 774         struct winch *winch = data;
 775         struct tty_struct *tty;
 776         struct line *line;
 777         int err;
 778         char c;
 779
 780         if(winch->fd != -1){
 781                 err = generic_read(winch->fd, &c, NULL);
 782                 if(err < 0){
 783                         if(err != -EAGAIN){
 784                                 printk("winch_interrupt : read failed, "
 785                                        "errno = %d\n", -err);
 786                                 printk("fd %d is losing SIGWINCH support\n",
 787                                        winch->tty_fd);
 788                                 return IRQ_HANDLED;
 789                         }
 790                         goto out;
 791                 }
 792         }
 793         tty  = winch->tty;
 794         if (tty != NULL) {
 795                 line = tty->driver_data;
 796                 chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 797                                  &tty->winsize.ws_col);
 798                 kill_pg(tty->pgrp, SIGWINCH, 1);
 799         }
 800  out:
 801         if(winch->fd != -1)
 802                 reactivate_fd(winch->fd, WINCH_IRQ);
 803         return IRQ_HANDLED;
 804 }
 805
 806 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
 807 {
 808         struct winch *winch;
 809
 810         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 811         if (winch == NULL) {
 812                 printk("register_winch_irq - kmalloc failed\n");
 813                 return;
 814         }
 815
 816         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 817                                    .fd          = fd,
 818                                    .tty_fd      = tty_fd,
 819                                    .pid         = pid,
 820                                    .tty         = tty });
 821
 822         spin_lock(&winch_handler_lock);
 823         list_add(&winch->list, &winch_handlers);
 824         spin_unlock(&winch_handler_lock);
 825
 826         if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 827                           IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 828                           "winch", winch) < 0)
 829                 printk("register_winch_irq - failed to register IRQ\n");
 830 }
 831
 832 static void free_winch(struct winch *winch)
 833 {
 834         list_del(&winch->list);
 835
 836         if(winch->pid != -1)
 837                 os_kill_process(winch->pid, 1);
 838         if(winch->fd != -1)
 839                 os_close_file(winch->fd);
 840
 841         free_irq(WINCH_IRQ, winch);
 842         kfree(winch);
 843 }
 844
 845 static void unregister_winch(struct tty_struct *tty)
 846 {
 847         struct list_head *ele;
 848         struct winch *winch;
 849
 850         spin_lock(&winch_handler_lock);
 851
 852         list_for_each(ele, &winch_handlers){
 853                 winch = list_entry(ele, struct winch, list);
 854                 if(winch->tty == tty){
 855                         free_winch(winch);
 856                         break;
 857                 }
 858         }
 859         spin_unlock(&winch_handler_lock);
 860 }
 861
 862 static void winch_cleanup(void)
 863 {
 864         struct list_head *ele, *next;
 865         struct winch *winch;
 866
 867         spin_lock(&winch_handler_lock);
 868
 869         list_for_each_safe(ele, next, &winch_handlers){
 870                 winch = list_entry(ele, struct winch, list);
 871                 free_winch(winch);
 872         }
 873
 874         spin_unlock(&winch_handler_lock);
 875 }
 876 __uml_exitcall(winch_cleanup);
 877
 878 char *add_xterm_umid(char *base)
 879 {
 880         char *umid, *title;
 881         int len;
 882
 883         umid = get_umid();
 884         if(*umid == '\0')
 885                 return base;
 886
 887         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 888         title = kmalloc(len, GFP_KERNEL);
 889         if(title == NULL){
 890                 printk("Failed to allocate buffer for xterm title\n");
 891                 return base;
 892         }
 893
 894         snprintf(title, len, "%s (%s)", base, umid);
 895         return title;
 896 }