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   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 "linux/devfs_fs_kernel.h"
  12 #include "asm/uaccess.h"
  13 #include "chan_kern.h"
  14 #include "irq_user.h"
  15 #include "line.h"
  16 #include "kern.h"
  17 #include "user_util.h"
  18 #include "kern_util.h"
  19 #include "os.h"
  20 #include "irq_kern.h"
  21
  22 #define LINE_BUFSIZE 4096
  23
  24 static irqreturn_t line_interrupt(int irq, void *data, struct pt_regs *unused)
  25 {
  26         struct tty_struct *tty = data;
  27         struct line *line = tty->driver_data;
  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(void *arg)
  35 {
  36         struct tty_struct *tty = arg;
  37         struct line *line = tty->driver_data;
  38
  39         line_interrupt(line->driver->read_irq, arg, NULL);
  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                 //return 0;
 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 termios * old)
 249 {
 250         /* nothing */
 251 }
 252
 253 static 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 static irqreturn_t line_write_interrupt(int irq, void *data,
 343                                         struct pt_regs *unused)
 344 {
 345         struct tty_struct *tty = data;
 346         struct line *line = tty->driver_data;
 347         int err;
 348
 349         /* Interrupts are enabled here because we registered the interrupt with
 350          * SA_INTERRUPT (see line_setup_irq).*/
 351
 352         spin_lock_irq(&line->lock);
 353         err = flush_buffer(line);
 354         if (err == 0) {
 355                 return IRQ_NONE;
 356         } else if(err < 0) {
 357                 line->head = line->buffer;
 358                 line->tail = line->buffer;
 359         }
 360         spin_unlock_irq(&line->lock);
 361
 362         if(tty == NULL)
 363                 return IRQ_NONE;
 364
 365         if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
 366            (tty->ldisc.write_wakeup != NULL))
 367                 (tty->ldisc.write_wakeup)(tty);
 368
 369         /* BLOCKING mode
 370          * In blocking mode, everything sleeps on tty->write_wait.
 371          * Sleeping in the console driver would break non-blocking
 372          * writes.
 373          */
 374
 375         if (waitqueue_active(&tty->write_wait))
 376                 wake_up_interruptible(&tty->write_wait);
 377         return IRQ_HANDLED;
 378 }
 379
 380 int line_setup_irq(int fd, int input, int output, struct tty_struct *tty)
 381 {
 382         struct line *line = tty->driver_data;
 383         struct line_driver *driver = line->driver;
 384         int err = 0, flags = SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM;
 385
 386         if (input)
 387                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 388                                        line_interrupt, flags,
 389                                        driver->read_irq_name, tty);
 390         if (err)
 391                 return err;
 392         if (output)
 393                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 394                                         line_write_interrupt, flags,
 395                                         driver->write_irq_name, tty);
 396         line->have_irq = 1;
 397         return err;
 398 }
 399
 400 void line_disable(struct tty_struct *tty, int current_irq)
 401 {
 402         struct line *line = tty->driver_data;
 403
 404         if(!line->have_irq)
 405                 return;
 406
 407         if(line->driver->read_irq == current_irq)
 408                 free_irq_later(line->driver->read_irq, tty);
 409         else {
 410                 free_irq(line->driver->read_irq, tty);
 411         }
 412
 413         if(line->driver->write_irq == current_irq)
 414                 free_irq_later(line->driver->write_irq, tty);
 415         else {
 416                 free_irq(line->driver->write_irq, tty);
 417         }
 418
 419         line->have_irq = 0;
 420 }
 421
 422 int line_open(struct line *lines, struct tty_struct *tty,
 423               struct chan_opts *opts)
 424 {
 425         struct line *line;
 426         int err = 0;
 427
 428         line = &lines[tty->index];
 429         tty->driver_data = line;
 430
 431         /* The IRQ which takes this lock is not yet enabled and won't be run
 432          * before the end, so we don't need to use spin_lock_irq.*/
 433         spin_lock(&line->lock);
 434         if (tty->count == 1) {
 435                 if (!line->valid) {
 436                         err = -ENODEV;
 437                         goto out;
 438                 }
 439                 if (list_empty(&line->chan_list)) {
 440                         err = parse_chan_pair(line->init_str, &line->chan_list,
 441                                               line->init_pri, tty->index, opts);
 442                         if(err) goto out;
 443                         err = open_chan(&line->chan_list);
 444                         if(err) goto out;
 445                 }
 446                 /* Here the interrupt is registered.*/
 447                 enable_chan(&line->chan_list, tty);
 448                 INIT_WORK(&line->task, line_timer_cb, tty);
 449         }
 450
 451         if(!line->sigio){
 452                 chan_enable_winch(&line->chan_list, tty);
 453                 line->sigio = 1;
 454         }
 455         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 456                          &tty->winsize.ws_col);
 457         line->count++;
 458
 459 out:
 460         spin_unlock(&line->lock);
 461         return err;
 462 }
 463
 464 static void unregister_winch(struct tty_struct *tty);
 465
 466 void line_close(struct tty_struct *tty, struct file * filp)
 467 {
 468         struct line *line = tty->driver_data;
 469
 470         /* XXX: I assume this should be called in process context, not with
 471          *  interrupts disabled!
 472          */
 473         spin_lock_irq(&line->lock);
 474
 475         /* We ignore the error anyway! */
 476         flush_buffer(line);
 477
 478         line->count--;
 479         if (tty->count == 1) {
 480                 line_disable(tty, -1);
 481                 tty->driver_data = NULL;
 482         }
 483
 484         if((line->count == 0) && line->sigio){
 485                 unregister_winch(tty);
 486                 line->sigio = 0;
 487         }
 488
 489         spin_unlock_irq(&line->lock);
 490 }
 491
 492 void close_lines(struct line *lines, int nlines)
 493 {
 494         int i;
 495
 496         for(i = 0; i < nlines; i++)
 497                 close_chan(&lines[i].chan_list);
 498 }
 499
 500 /* Common setup code for both startup command line and mconsole initialization.
 501  * @lines contains the the array (of size @num) to modify;
 502  * @init is the setup string;
 503  * @all_allowed is a boolean saying if we can setup the whole @lines
 504  * at once. For instance, it will be usually true for startup init. (where we
 505  * can use con=xterm) and false for mconsole.*/
 506
 507 int line_setup(struct line *lines, unsigned int num, char *init, int all_allowed)
 508 {
 509         int i, n;
 510         char *end;
 511
 512         if(*init == '=') {
 513                 /* We said con=/ssl= instead of con#=, so we are configuring all
 514                  * consoles at once.*/
 515                 n = -1;
 516         }
 517         else {
 518                 n = simple_strtoul(init, &end, 0);
 519                 if(*end != '='){
 520                         printk(KERN_ERR "line_setup failed to parse \"%s\"\n",
 521                                init);
 522                         return 0;
 523                 }
 524                 init = end;
 525         }
 526         init++;
 527
 528         if (n >= (signed int) num) {
 529                 printk("line_setup - %d out of range ((0 ... %d) allowed)\n",
 530                        n, num - 1);
 531                 return 0;
 532         }
 533         else if (n >= 0){
 534                 if (lines[n].count > 0) {
 535                         printk("line_setup - device %d is open\n", n);
 536                         return 0;
 537                 }
 538                 if (lines[n].init_pri <= INIT_ONE){
 539                         lines[n].init_pri = INIT_ONE;
 540                         if (!strcmp(init, "none"))
 541                                 lines[n].valid = 0;
 542                         else {
 543                                 lines[n].init_str = init;
 544                                 lines[n].valid = 1;
 545                         }
 546                 }
 547         }
 548         else if(!all_allowed){
 549                 printk("line_setup - can't configure all devices from "
 550                        "mconsole\n");
 551                 return 0;
 552         }
 553         else {
 554                 for(i = 0; i < num; i++){
 555                         if(lines[i].init_pri <= INIT_ALL){
 556                                 lines[i].init_pri = INIT_ALL;
 557                                 if(!strcmp(init, "none")) lines[i].valid = 0;
 558                                 else {
 559                                         lines[i].init_str = init;
 560                                         lines[i].valid = 1;
 561                                 }
 562                         }
 563                 }
 564         }
 565         return 1;
 566 }
 567
 568 int line_config(struct line *lines, unsigned int num, char *str)
 569 {
 570         char *new;
 571
 572         new = kstrdup(str, GFP_KERNEL);
 573         if(new == NULL){
 574                 printk("line_config - kstrdup failed\n");
 575                 return -ENOMEM;
 576         }
 577         return !line_setup(lines, num, new, 0);
 578 }
 579
 580 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 581                     int size, char **error_out)
 582 {
 583         struct line *line;
 584         char *end;
 585         int dev, n = 0;
 586
 587         dev = simple_strtoul(name, &end, 0);
 588         if((*end != '\0') || (end == name)){
 589                 *error_out = "line_get_config failed to parse device number";
 590                 return 0;
 591         }
 592
 593         if((dev < 0) || (dev >= num)){
 594                 *error_out = "device number out of range";
 595                 return 0;
 596         }
 597
 598         line = &lines[dev];
 599
 600         spin_lock(&line->lock);
 601         if(!line->valid)
 602                 CONFIG_CHUNK(str, size, n, "none", 1);
 603         else if(line->count == 0)
 604                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 605         else n = chan_config_string(&line->chan_list, str, size, error_out);
 606         spin_unlock(&line->lock);
 607
 608         return n;
 609 }
 610
 611 int line_id(char **str, int *start_out, int *end_out)
 612 {
 613         char *end;
 614         int n;
 615
 616         n = simple_strtoul(*str, &end, 0);
 617         if((*end != '\0') || (end == *str))
 618                 return -1;
 619
 620         *str = end;
 621         *start_out = n;
 622         *end_out = n;
 623         return n;
 624 }
 625
 626 int line_remove(struct line *lines, unsigned int num, int n)
 627 {
 628         char config[sizeof("conxxxx=none\0")];
 629
 630         sprintf(config, "%d=none", n);
 631         return !line_setup(lines, num, config, 0);
 632 }
 633
 634 struct tty_driver *line_register_devfs(struct lines *set,
 635                          struct line_driver *line_driver,
 636                          struct tty_operations *ops, struct line *lines,
 637                          int nlines)
 638 {
 639         int i;
 640         struct tty_driver *driver = alloc_tty_driver(nlines);
 641
 642         if (!driver)
 643                 return NULL;
 644
 645         driver->driver_name = line_driver->name;
 646         driver->name = line_driver->device_name;
 647         driver->devfs_name = line_driver->devfs_name;
 648         driver->major = line_driver->major;
 649         driver->minor_start = line_driver->minor_start;
 650         driver->type = line_driver->type;
 651         driver->subtype = line_driver->subtype;
 652         driver->flags = TTY_DRIVER_REAL_RAW;
 653         driver->init_termios = tty_std_termios;
 654         tty_set_operations(driver, ops);
 655
 656         if (tty_register_driver(driver)) {
 657                 printk("%s: can't register %s driver\n",
 658                        __FUNCTION__,line_driver->name);
 659                 put_tty_driver(driver);
 660                 return NULL;
 661         }
 662
 663         for(i = 0; i < nlines; i++){
 664                 if(!lines[i].valid)
 665                         tty_unregister_device(driver, i);
 666         }
 667
 668         mconsole_register_dev(&line_driver->mc);
 669         return driver;
 670 }
 671
 672 static spinlock_t winch_handler_lock;
 673 LIST_HEAD(winch_handlers);
 674
 675 void lines_init(struct line *lines, int nlines)
 676 {
 677         struct line *line;
 678         int i;
 679
 680         spin_lock_init(&winch_handler_lock);
 681         for(i = 0; i < nlines; i++){
 682                 line = &lines[i];
 683                 INIT_LIST_HEAD(&line->chan_list);
 684                 spin_lock_init(&line->lock);
 685                 if(line->init_str == NULL)
 686                         continue;
 687
 688                 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
 689                 if(line->init_str == NULL)
 690                         printk("lines_init - kstrdup returned NULL\n");
 691         }
 692 }
 693
 694 struct winch {
 695         struct list_head list;
 696         int fd;
 697         int tty_fd;
 698         int pid;
 699         struct tty_struct *tty;
 700 };
 701
 702 irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
 703 {
 704         struct winch *winch = data;
 705         struct tty_struct *tty;
 706         struct line *line;
 707         int err;
 708         char c;
 709
 710         if(winch->fd != -1){
 711                 err = generic_read(winch->fd, &c, NULL);
 712                 if(err < 0){
 713                         if(err != -EAGAIN){
 714                                 printk("winch_interrupt : read failed, "
 715                                        "errno = %d\n", -err);
 716                                 printk("fd %d is losing SIGWINCH support\n",
 717                                        winch->tty_fd);
 718                                 return IRQ_HANDLED;
 719                         }
 720                         goto out;
 721                 }
 722         }
 723         tty  = winch->tty;
 724         if (tty != NULL) {
 725                 line = tty->driver_data;
 726                 chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 727                                  &tty->winsize.ws_col);
 728                 kill_pg(tty->pgrp, SIGWINCH, 1);
 729         }
 730  out:
 731         if(winch->fd != -1)
 732                 reactivate_fd(winch->fd, WINCH_IRQ);
 733         return IRQ_HANDLED;
 734 }
 735
 736 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
 737 {
 738         struct winch *winch;
 739
 740         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 741         if (winch == NULL) {
 742                 printk("register_winch_irq - kmalloc failed\n");
 743                 return;
 744         }
 745
 746         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 747                                    .fd          = fd,
 748                                    .tty_fd      = tty_fd,
 749                                    .pid         = pid,
 750                                    .tty         = tty });
 751
 752         spin_lock(&winch_handler_lock);
 753         list_add(&winch->list, &winch_handlers);
 754         spin_unlock(&winch_handler_lock);
 755
 756         if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 757                           SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
 758                           "winch", winch) < 0)
 759                 printk("register_winch_irq - failed to register IRQ\n");
 760 }
 761
 762 static void unregister_winch(struct tty_struct *tty)
 763 {
 764         struct list_head *ele;
 765         struct winch *winch, *found = NULL;
 766
 767         spin_lock(&winch_handler_lock);
 768         list_for_each(ele, &winch_handlers){
 769                 winch = list_entry(ele, struct winch, list);
 770                 if(winch->tty == tty){
 771                         found = winch;
 772                         break;
 773                 }
 774         }
 775         if(found == NULL)
 776                 goto err;
 777
 778         list_del(&winch->list);
 779         spin_unlock(&winch_handler_lock);
 780
 781         if(winch->pid != -1)
 782                 os_kill_process(winch->pid, 1);
 783
 784         free_irq(WINCH_IRQ, winch);
 785         kfree(winch);
 786
 787         return;
 788 err:
 789         spin_unlock(&winch_handler_lock);
 790 }
 791
 792 /* XXX: No lock as it's an exitcall... is this valid? Depending on cleanup
 793  * order... are we sure that nothing else is done on the list? */
 794 static void winch_cleanup(void)
 795 {
 796         struct list_head *ele;
 797         struct winch *winch;
 798
 799         list_for_each(ele, &winch_handlers){
 800                 winch = list_entry(ele, struct winch, list);
 801                 if(winch->fd != -1){
 802                         /* Why is this different from the above free_irq(),
 803                          * which deactivates SIGIO? This searches the FD
 804                          * somewhere else and removes it from the list... */
 805                         deactivate_fd(winch->fd, WINCH_IRQ);
 806                         os_close_file(winch->fd);
 807                 }
 808                 if(winch->pid != -1)
 809                         os_kill_process(winch->pid, 1);
 810         }
 811 }
 812 __uml_exitcall(winch_cleanup);
 813
 814 char *add_xterm_umid(char *base)
 815 {
 816         char *umid, *title;
 817         int len;
 818
 819         umid = get_umid(1);
 820         if(umid == NULL)
 821                 return base;
 822
 823         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 824         title = kmalloc(len, GFP_KERNEL);
 825         if(title == NULL){
 826                 printk("Failed to allocate buffer for xterm title\n");
 827                 return base;
 828         }
 829
 830         snprintf(title, len, "%s (%s)", base, umid);
 831         return title;
 832 }