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 int setup_one_line(struct line *lines, int n, char *init, int init_prio,
 553                           char **error_out)
 554 {
 555         struct line *line = &lines[n];
 556         int err = -EINVAL;
 557
 558         spin_lock(&line->count_lock);
 559
 560         if(line->tty != NULL){
 561                 *error_out = "Device is already open";
 562                 goto out;
 563         }
 564
 565         if (line->init_pri <= init_prio){
 566                 line->init_pri = init_prio;
 567                 if (!strcmp(init, "none"))
 568                         line->valid = 0;
 569                 else {
 570                         line->init_str = init;
 571                         line->valid = 1;
 572                 }
 573         }
 574         err = 0;
 575 out:
 576         spin_unlock(&line->count_lock);
 577         return err;
 578 }
 579
 580 /* Common setup code for both startup command line and mconsole initialization.
 581  * @lines contains the array (of size @num) to modify;
 582  * @init is the setup string;
 583  * @error_out is an error string in the case of failure;
 584  */
 585
 586 int line_setup(struct line *lines, unsigned int num, char *init,
 587                char **error_out)
 588 {
 589         int i, n, err;
 590         char *end;
 591
 592         if(*init == '=') {
 593                 /* We said con=/ssl= instead of con#=, so we are configuring all
 594                  * consoles at once.*/
 595                 n = -1;
 596         }
 597         else {
 598                 n = simple_strtoul(init, &end, 0);
 599                 if(*end != '='){
 600                         *error_out = "Couldn't parse device number";
 601                         return -EINVAL;
 602                 }
 603                 init = end;
 604         }
 605         init++;
 606
 607         if (n >= (signed int) num) {
 608                 *error_out = "Device number out of range";
 609                 return -EINVAL;
 610         }
 611         else if (n >= 0){
 612                 err = setup_one_line(lines, n, init, INIT_ONE, error_out);
 613                 if(err)
 614                         return err;
 615         }
 616         else {
 617                 for(i = 0; i < num; i++){
 618                         err = setup_one_line(lines, i, init, INIT_ALL,
 619                                              error_out);
 620                         if(err)
 621                                 return err;
 622                 }
 623         }
 624         return n == -1 ? num : n;
 625 }
 626
 627 int line_config(struct line *lines, unsigned int num, char *str,
 628                 const struct chan_opts *opts, char **error_out)
 629 {
 630         struct line *line;
 631         char *new;
 632         int n;
 633
 634         if(*str == '='){
 635                 *error_out = "Can't configure all devices from mconsole";
 636                 return -EINVAL;
 637         }
 638
 639         new = kstrdup(str, GFP_KERNEL);
 640         if(new == NULL){
 641                 *error_out = "Failed to allocate memory";
 642                 return -ENOMEM;
 643         }
 644         n = line_setup(lines, num, new, error_out);
 645         if(n < 0)
 646                 return n;
 647
 648         line = &lines[n];
 649         return parse_chan_pair(line->init_str, line, n, opts, error_out);
 650 }
 651
 652 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 653                     int size, char **error_out)
 654 {
 655         struct line *line;
 656         char *end;
 657         int dev, n = 0;
 658
 659         dev = simple_strtoul(name, &end, 0);
 660         if((*end != '\0') || (end == name)){
 661                 *error_out = "line_get_config failed to parse device number";
 662                 return 0;
 663         }
 664
 665         if((dev < 0) || (dev >= num)){
 666                 *error_out = "device number out of range";
 667                 return 0;
 668         }
 669
 670         line = &lines[dev];
 671
 672         spin_lock(&line->count_lock);
 673         if(!line->valid)
 674                 CONFIG_CHUNK(str, size, n, "none", 1);
 675         else if(line->tty == NULL)
 676                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 677         else n = chan_config_string(&line->chan_list, str, size, error_out);
 678         spin_unlock(&line->count_lock);
 679
 680         return n;
 681 }
 682
 683 int line_id(char **str, int *start_out, int *end_out)
 684 {
 685         char *end;
 686         int n;
 687
 688         n = simple_strtoul(*str, &end, 0);
 689         if((*end != '\0') || (end == *str))
 690                 return -1;
 691
 692         *str = end;
 693         *start_out = n;
 694         *end_out = n;
 695         return n;
 696 }
 697
 698 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 699 {
 700         int err;
 701         char config[sizeof("conxxxx=none\0")];
 702
 703         sprintf(config, "%d=none", n);
 704         err = line_setup(lines, num, config, error_out);
 705         if(err >= 0)
 706                 err = 0;
 707         return err;
 708 }
 709
 710 struct tty_driver *line_register_devfs(struct lines *set,
 711                                        struct line_driver *line_driver,
 712                                        const struct tty_operations *ops,
 713                                        struct line *lines, int nlines)
 714 {
 715         int i;
 716         struct tty_driver *driver = alloc_tty_driver(nlines);
 717
 718         if (!driver)
 719                 return NULL;
 720
 721         driver->driver_name = line_driver->name;
 722         driver->name = line_driver->device_name;
 723         driver->major = line_driver->major;
 724         driver->minor_start = line_driver->minor_start;
 725         driver->type = line_driver->type;
 726         driver->subtype = line_driver->subtype;
 727         driver->flags = TTY_DRIVER_REAL_RAW;
 728         driver->init_termios = tty_std_termios;
 729         tty_set_operations(driver, ops);
 730
 731         if (tty_register_driver(driver)) {
 732                 printk("%s: can't register %s driver\n",
 733                        __FUNCTION__,line_driver->name);
 734                 put_tty_driver(driver);
 735                 return NULL;
 736         }
 737
 738         for(i = 0; i < nlines; i++){
 739                 if(!lines[i].valid)
 740                         tty_unregister_device(driver, i);
 741         }
 742
 743         mconsole_register_dev(&line_driver->mc);
 744         return driver;
 745 }
 746
 747 static DEFINE_SPINLOCK(winch_handler_lock);
 748 static LIST_HEAD(winch_handlers);
 749
 750 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 751 {
 752         struct line *line;
 753         char *error;
 754         int i;
 755
 756         for(i = 0; i < nlines; i++){
 757                 line = &lines[i];
 758                 INIT_LIST_HEAD(&line->chan_list);
 759                 mutex_init(&line->open_mutex);
 760
 761                 if(line->init_str == NULL)
 762                         continue;
 763
 764                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
 765                 if(line->init_str == NULL)
 766                         printk("lines_init - kstrdup returned NULL\n");
 767
 768                 if(parse_chan_pair(line->init_str, line, i, opts, &error)){
 769                         printk("parse_chan_pair failed for device %d : %s\n",
 770                                i, error);
 771                         line->valid = 0;
 772                 }
 773         }
 774 }
 775
 776 struct winch {
 777         struct list_head list;
 778         int fd;
 779         int tty_fd;
 780         int pid;
 781         struct tty_struct *tty;
 782 };
 783
 784 static irqreturn_t winch_interrupt(int irq, void *data)
 785 {
 786         struct winch *winch = data;
 787         struct tty_struct *tty;
 788         struct line *line;
 789         int err;
 790         char c;
 791
 792         if(winch->fd != -1){
 793                 err = generic_read(winch->fd, &c, NULL);
 794                 if(err < 0){
 795                         if(err != -EAGAIN){
 796                                 printk("winch_interrupt : read failed, "
 797                                        "errno = %d\n", -err);
 798                                 printk("fd %d is losing SIGWINCH support\n",
 799                                        winch->tty_fd);
 800                                 return IRQ_HANDLED;
 801                         }
 802                         goto out;
 803                 }
 804         }
 805         tty  = winch->tty;
 806         if (tty != NULL) {
 807                 line = tty->driver_data;
 808                 chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 809                                  &tty->winsize.ws_col);
 810                 kill_pg(tty->pgrp, SIGWINCH, 1);
 811         }
 812  out:
 813         if(winch->fd != -1)
 814                 reactivate_fd(winch->fd, WINCH_IRQ);
 815         return IRQ_HANDLED;
 816 }
 817
 818 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
 819 {
 820         struct winch *winch;
 821
 822         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 823         if (winch == NULL) {
 824                 printk("register_winch_irq - kmalloc failed\n");
 825                 return;
 826         }
 827
 828         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 829                                    .fd          = fd,
 830                                    .tty_fd      = tty_fd,
 831                                    .pid         = pid,
 832                                    .tty         = tty });
 833
 834         spin_lock(&winch_handler_lock);
 835         list_add(&winch->list, &winch_handlers);
 836         spin_unlock(&winch_handler_lock);
 837
 838         if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 839                           IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 840                           "winch", winch) < 0)
 841                 printk("register_winch_irq - failed to register IRQ\n");
 842 }
 843
 844 static void free_winch(struct winch *winch)
 845 {
 846         list_del(&winch->list);
 847
 848         if(winch->pid != -1)
 849                 os_kill_process(winch->pid, 1);
 850         if(winch->fd != -1)
 851                 os_close_file(winch->fd);
 852
 853         free_irq(WINCH_IRQ, winch);
 854         kfree(winch);
 855 }
 856
 857 static void unregister_winch(struct tty_struct *tty)
 858 {
 859         struct list_head *ele;
 860         struct winch *winch;
 861
 862         spin_lock(&winch_handler_lock);
 863
 864         list_for_each(ele, &winch_handlers){
 865                 winch = list_entry(ele, struct winch, list);
 866                 if(winch->tty == tty){
 867                         free_winch(winch);
 868                         break;
 869                 }
 870         }
 871         spin_unlock(&winch_handler_lock);
 872 }
 873
 874 static void winch_cleanup(void)
 875 {
 876         struct list_head *ele, *next;
 877         struct winch *winch;
 878
 879         spin_lock(&winch_handler_lock);
 880
 881         list_for_each_safe(ele, next, &winch_handlers){
 882                 winch = list_entry(ele, struct winch, list);
 883                 free_winch(winch);
 884         }
 885
 886         spin_unlock(&winch_handler_lock);
 887 }
 888 __uml_exitcall(winch_cleanup);
 889
 890 char *add_xterm_umid(char *base)
 891 {
 892         char *umid, *title;
 893         int len;
 894
 895         umid = get_umid();
 896         if(*umid == '\0')
 897                 return base;
 898
 899         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 900         title = kmalloc(len, GFP_KERNEL);
 901         if(title == NULL){
 902                 printk("Failed to allocate buffer for xterm title\n");
 903                 return base;
 904         }
 905
 906         snprintf(title, len, "%s (%s)", base, umid);
 907         return title;
 908 }