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 "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         } else {
 128                 /* The circular buffer is wrapping */
 129                 memcpy(line->tail, buf, end);
 130                 buf += end;
 131                 memcpy(line->buffer, buf, len - end);
 132                 line->tail = line->buffer + len - end;
 133         }
 134
 135         return len;
 136 }
 137
 138 /*
 139  * Flushes the ring buffer to the output channels. That is, write_chan is
 140  * called, passing it line->head as buffer, and an appropriate count.
 141  *
 142  * On exit, returns 1 when the buffer is empty,
 143  * 0 when the buffer is not empty on exit,
 144  * and -errno when an error occurred.
 145  *
 146  * Must be called while holding line->lock!*/
 147 static int flush_buffer(struct line *line)
 148 {
 149         int n, count;
 150
 151         if ((line->buffer == NULL) || (line->head == line->tail))
 152                 return 1;
 153
 154         if (line->tail < line->head) {
 155                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
 156                 count = line->buffer + LINE_BUFSIZE - line->head;
 157
 158                 n = write_chan(&line->chan_list, line->head, count,
 159                                line->driver->write_irq);
 160                 if (n < 0)
 161                         return n;
 162                 if (n == count) {
 163                         /* We have flushed from ->head to buffer end, now we
 164                          * must flush only from the beginning to ->tail.*/
 165                         line->head = line->buffer;
 166                 } else {
 167                         line->head += n;
 168                         return 0;
 169                 }
 170         }
 171
 172         count = line->tail - line->head;
 173         n = write_chan(&line->chan_list, line->head, count,
 174                        line->driver->write_irq);
 175
 176         if(n < 0)
 177                 return n;
 178
 179         line->head += n;
 180         return line->head == line->tail;
 181 }
 182
 183 void line_flush_buffer(struct tty_struct *tty)
 184 {
 185         struct line *line = tty->driver_data;
 186         unsigned long flags;
 187         int err;
 188
 189         /*XXX: copied from line_write, verify if it is correct!*/
 190         if(tty->stopped)
 191                 return;
 192                 //return 0;
 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 termios * old)
 248 {
 249         /* nothing */
 250 }
 251
 252 static 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 static irqreturn_t line_write_interrupt(int irq, void *data,
 342                                         struct pt_regs *unused)
 343 {
 344         struct tty_struct *tty = data;
 345         struct line *line = tty->driver_data;
 346         int err;
 347
 348         /* Interrupts are enabled here because we registered the interrupt with
 349          * SA_INTERRUPT (see line_setup_irq).*/
 350
 351         spin_lock_irq(&line->lock);
 352         err = flush_buffer(line);
 353         if (err == 0) {
 354                 return IRQ_NONE;
 355         } else if(err < 0) {
 356                 line->head = line->buffer;
 357                 line->tail = line->buffer;
 358         }
 359         spin_unlock_irq(&line->lock);
 360
 361         if(tty == NULL)
 362                 return IRQ_NONE;
 363
 364         if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
 365            (tty->ldisc.write_wakeup != NULL))
 366                 (tty->ldisc.write_wakeup)(tty);
 367
 368         /* BLOCKING mode
 369          * In blocking mode, everything sleeps on tty->write_wait.
 370          * Sleeping in the console driver would break non-blocking
 371          * writes.
 372          */
 373
 374         if (waitqueue_active(&tty->write_wait))
 375                 wake_up_interruptible(&tty->write_wait);
 376         return IRQ_HANDLED;
 377 }
 378
 379 int line_setup_irq(int fd, int input, int output, struct tty_struct *tty)
 380 {
 381         struct line *line = tty->driver_data;
 382         struct line_driver *driver = line->driver;
 383         int err = 0, flags = SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM;
 384
 385         if (input)
 386                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 387                                        line_interrupt, flags,
 388                                        driver->read_irq_name, tty);
 389         if (err)
 390                 return err;
 391         if (output)
 392                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 393                                         line_write_interrupt, flags,
 394                                         driver->write_irq_name, tty);
 395         line->have_irq = 1;
 396         return err;
 397 }
 398
 399 void line_disable(struct tty_struct *tty, int current_irq)
 400 {
 401         struct line *line = tty->driver_data;
 402
 403         if(!line->have_irq)
 404                 return;
 405
 406         if(line->driver->read_irq == current_irq)
 407                 free_irq_later(line->driver->read_irq, tty);
 408         else {
 409                 free_irq(line->driver->read_irq, tty);
 410         }
 411
 412         if(line->driver->write_irq == current_irq)
 413                 free_irq_later(line->driver->write_irq, tty);
 414         else {
 415                 free_irq(line->driver->write_irq, tty);
 416         }
 417
 418         line->have_irq = 0;
 419 }
 420
 421 int line_open(struct line *lines, struct tty_struct *tty,
 422               struct chan_opts *opts)
 423 {
 424         struct line *line;
 425         int err = 0;
 426
 427         line = &lines[tty->index];
 428         tty->driver_data = line;
 429
 430         /* The IRQ which takes this lock is not yet enabled and won't be run
 431          * before the end, so we don't need to use spin_lock_irq.*/
 432         spin_lock(&line->lock);
 433         if (tty->count == 1) {
 434                 if (!line->valid) {
 435                         err = -ENODEV;
 436                         goto out;
 437                 }
 438                 if (list_empty(&line->chan_list)) {
 439                         err = parse_chan_pair(line->init_str, &line->chan_list,
 440                                               line->init_pri, tty->index, opts);
 441                         if(err) goto out;
 442                         err = open_chan(&line->chan_list);
 443                         if(err) goto out;
 444                 }
 445                 /* Here the interrupt is registered.*/
 446                 enable_chan(&line->chan_list, tty);
 447                 INIT_WORK(&line->task, line_timer_cb, tty);
 448         }
 449
 450         if(!line->sigio){
 451                 chan_enable_winch(&line->chan_list, tty);
 452                 line->sigio = 1;
 453         }
 454         chan_window_size(&line->chan_list, &tty->winsize.ws_row,
 455                          &tty->winsize.ws_col);
 456         line->count++;
 457
 458 out:
 459         spin_unlock(&line->lock);
 460         return err;
 461 }
 462
 463 static void unregister_winch(struct tty_struct *tty);
 464
 465 void line_close(struct tty_struct *tty, struct file * filp)
 466 {
 467         struct line *line = tty->driver_data;
 468
 469         /* XXX: I assume this should be called in process context, not with
 470          *  interrupts disabled!
 471          */
 472         spin_lock_irq(&line->lock);
 473
 474         /* We ignore the error anyway! */
 475         flush_buffer(line);
 476
 477         line->count--;
 478         if (tty->count == 1) {
 479                 line_disable(tty, -1);
 480                 tty->driver_data = NULL;
 481         }
 482
 483         if((line->count == 0) && line->sigio){
 484                 unregister_winch(tty);
 485                 line->sigio = 0;
 486         }
 487
 488         spin_unlock_irq(&line->lock);
 489 }
 490
 491 void close_lines(struct line *lines, int nlines)
 492 {
 493         int i;
 494
 495         for(i = 0; i < nlines; i++)
 496                 close_chan(&lines[i].chan_list);
 497 }
 498
 499 /* Common setup code for both startup command line and mconsole initialization.
 500  * @lines contains the the array (of size @num) to modify;
 501  * @init is the setup string;
 502  * @all_allowed is a boolean saying if we can setup the whole @lines
 503  * at once. For instance, it will be usually true for startup init. (where we
 504  * can use con=xterm) and false for mconsole.*/
 505
 506 int line_setup(struct line *lines, unsigned int num, char *init, int all_allowed)
 507 {
 508         int i, n;
 509         char *end;
 510
 511         if(*init == '=') {
 512                 /* We said con=/ssl= instead of con#=, so we are configuring all
 513                  * consoles at once.*/
 514                 n = -1;
 515         } else {
 516                 n = simple_strtoul(init, &end, 0);
 517                 if(*end != '='){
 518                         printk(KERN_ERR "line_setup failed to parse \"%s\"\n",
 519                                init);
 520                         return 0;
 521                 }
 522                 init = end;
 523         }
 524         init++;
 525
 526         if (n >= (signed int) num) {
 527                 printk("line_setup - %d out of range ((0 ... %d) allowed)\n",
 528                        n, num - 1);
 529                 return 0;
 530         } else if (n >= 0){
 531                 if (lines[n].count > 0) {
 532                         printk("line_setup - device %d is open\n", n);
 533                         return 0;
 534                 }
 535                 if (lines[n].init_pri <= INIT_ONE){
 536                         lines[n].init_pri = INIT_ONE;
 537                         if (!strcmp(init, "none"))
 538                                 lines[n].valid = 0;
 539                         else {
 540                                 lines[n].init_str = init;
 541                                 lines[n].valid = 1;
 542                         }
 543                 }
 544         } else if(!all_allowed){
 545                 printk("line_setup - can't configure all devices from "
 546                        "mconsole\n");
 547                 return 0;
 548         } else {
 549                 for(i = 0; i < num; i++){
 550                         if(lines[i].init_pri <= INIT_ALL){
 551                                 lines[i].init_pri = INIT_ALL;
 552                                 if(!strcmp(init, "none")) lines[i].valid = 0;
 553                                 else {
 554                                         lines[i].init_str = init;
 555                                         lines[i].valid = 1;
 556                                 }
 557                         }
 558                 }
 559         }
 560         return 1;
 561 }
 562
 563 int line_config(struct line *lines, unsigned int num, char *str)
 564 {
 565         char *new = uml_strdup(str);
 566
 567         if(new == NULL){
 568                 printk("line_config - uml_strdup failed\n");
 569                 return -ENOMEM;
 570         }
 571         return !line_setup(lines, num, new, 0);
 572 }
 573
 574 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 575                     int size, char **error_out)
 576 {
 577         struct line *line;
 578         char *end;
 579         int dev, n = 0;
 580
 581         dev = simple_strtoul(name, &end, 0);
 582         if((*end != '\0') || (end == name)){
 583                 *error_out = "line_get_config failed to parse device number";
 584                 return 0;
 585         }
 586
 587         if((dev < 0) || (dev >= num)){
 588                 *error_out = "device number out of range";
 589                 return 0;
 590         }
 591
 592         line = &lines[dev];
 593
 594         spin_lock(&line->lock);
 595         if(!line->valid)
 596                 CONFIG_CHUNK(str, size, n, "none", 1);
 597         else if(line->count == 0)
 598                 CONFIG_CHUNK(str, size, n, line->init_str, 1);
 599         else n = chan_config_string(&line->chan_list, str, size, error_out);
 600         spin_unlock(&line->lock);
 601
 602         return n;
 603 }
 604
 605 int line_id(char **str, int *start_out, int *end_out)
 606 {
 607         char *end;
 608         int n;
 609
 610         n = simple_strtoul(*str, &end, 0);
 611         if((*end != '\0') || (end == *str))
 612                 return -1;
 613
 614         *str = end;
 615         *start_out = n;
 616         *end_out = n;
 617         return n;
 618 }
 619
 620 int line_remove(struct line *lines, unsigned int num, int n)
 621 {
 622         char config[sizeof("conxxxx=none\0")];
 623
 624         sprintf(config, "%d=none", n);
 625         return !line_setup(lines, num, config, 0);
 626 }
 627
 628 struct tty_driver *line_register_devfs(struct lines *set,
 629                          struct line_driver *line_driver,
 630                          struct tty_operations *ops, struct line *lines,
 631                          int nlines)
 632 {
 633         int i;
 634         struct tty_driver *driver = alloc_tty_driver(nlines);
 635
 636         if (!driver)
 637                 return NULL;
 638
 639         driver->driver_name = line_driver->name;
 640         driver->name = line_driver->device_name;
 641         driver->devfs_name = line_driver->devfs_name;
 642         driver->major = line_driver->major;
 643         driver->minor_start = line_driver->minor_start;
 644         driver->type = line_driver->type;
 645         driver->subtype = line_driver->subtype;
 646         driver->flags = TTY_DRIVER_REAL_RAW;
 647         driver->init_termios = tty_std_termios;
 648         tty_set_operations(driver, ops);
 649
 650         if (tty_register_driver(driver)) {
 651                 printk("%s: can't register %s driver\n",
 652                        __FUNCTION__,line_driver->name);
 653                 put_tty_driver(driver);
 654                 return NULL;
 655         }
 656
 657         for(i = 0; i < nlines; i++){
 658                 if(!lines[i].valid)
 659                         tty_unregister_device(driver, i);
 660         }
 661
 662         mconsole_register_dev(&line_driver->mc);
 663         return driver;
 664 }
 665
 666 static spinlock_t winch_handler_lock;
 667 LIST_HEAD(winch_handlers);
 668
 669 void lines_init(struct line *lines, int nlines)
 670 {
 671         struct line *line;
 672         int i;
 673
 674         spin_lock_init(&winch_handler_lock);
 675         for(i = 0; i < nlines; i++){
 676                 line = &lines[i];
 677                 INIT_LIST_HEAD(&line->chan_list);
 678                 spin_lock_init(&line->lock);
 679                 if(line->init_str != NULL){
 680                         line->init_str = uml_strdup(line->init_str);
 681                         if(line->init_str == NULL)
 682                                 printk("lines_init - uml_strdup returned "
 683                                        "NULL\n");
 684                 }
 685         }
 686 }
 687
 688 struct winch {
 689         struct list_head list;
 690         int fd;
 691         int tty_fd;
 692         int pid;
 693         struct tty_struct *tty;
 694 };
 695
 696 irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
 697 {
 698         struct winch *winch = data;
 699         struct tty_struct *tty;
 700         struct line *line;
 701         int err;
 702         char c;
 703
 704         if(winch->fd != -1){
 705                 err = generic_read(winch->fd, &c, NULL);
 706                 if(err < 0){
 707                         if(err != -EAGAIN){
 708                                 printk("winch_interrupt : read failed, "
 709                                        "errno = %d\n", -err);
 710                                 printk("fd %d is losing SIGWINCH support\n",
 711                                        winch->tty_fd);
 712                                 return IRQ_HANDLED;
 713                         }
 714                         goto out;
 715                 }
 716         }
 717         tty  = winch->tty;
 718         if (tty != NULL) {
 719                 line = tty->driver_data;
 720                 chan_window_size(&line->chan_list,
 721                                  &tty->winsize.ws_row,
 722                                  &tty->winsize.ws_col);
 723                 kill_pg(tty->pgrp, SIGWINCH, 1);
 724         }
 725  out:
 726         if(winch->fd != -1)
 727                 reactivate_fd(winch->fd, WINCH_IRQ);
 728         return IRQ_HANDLED;
 729 }
 730
 731 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
 732 {
 733         struct winch *winch;
 734
 735         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 736         if (winch == NULL) {
 737                 printk("register_winch_irq - kmalloc failed\n");
 738                 return;
 739         }
 740
 741         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 742                                    .fd          = fd,
 743                                    .tty_fd      = tty_fd,
 744                                    .pid         = pid,
 745                                    .tty         = tty });
 746
 747         spin_lock(&winch_handler_lock);
 748         list_add(&winch->list, &winch_handlers);
 749         spin_unlock(&winch_handler_lock);
 750
 751         if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 752                           SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
 753                           "winch", winch) < 0)
 754                 printk("register_winch_irq - failed to register IRQ\n");
 755 }
 756
 757 static void unregister_winch(struct tty_struct *tty)
 758 {
 759         struct list_head *ele;
 760         struct winch *winch, *found = NULL;
 761
 762         spin_lock(&winch_handler_lock);
 763         list_for_each(ele, &winch_handlers){
 764                 winch = list_entry(ele, struct winch, list);
 765                 if(winch->tty == tty){
 766                         found = winch;
 767                         break;
 768                 }
 769         }
 770         if(found == NULL)
 771                 goto err;
 772
 773         list_del(&winch->list);
 774         spin_unlock(&winch_handler_lock);
 775
 776         if(winch->pid != -1)
 777                 os_kill_process(winch->pid, 1);
 778
 779         free_irq(WINCH_IRQ, winch);
 780         kfree(winch);
 781
 782         return;
 783 err:
 784         spin_unlock(&winch_handler_lock);
 785 }
 786
 787 /* XXX: No lock as it's an exitcall... is this valid? Depending on cleanup
 788  * order... are we sure that nothing else is done on the list? */
 789 static void winch_cleanup(void)
 790 {
 791         struct list_head *ele;
 792         struct winch *winch;
 793
 794         list_for_each(ele, &winch_handlers){
 795                 winch = list_entry(ele, struct winch, list);
 796                 if(winch->fd != -1){
 797                         /* Why is this different from the above free_irq(),
 798                          * which deactivates SIGIO? This searches the FD
 799                          * somewhere else and removes it from the list... */
 800                         deactivate_fd(winch->fd, WINCH_IRQ);
 801                         os_close_file(winch->fd);
 802                 }
 803                 if(winch->pid != -1)
 804                         os_kill_process(winch->pid, 1);
 805         }
 806 }
 807 __uml_exitcall(winch_cleanup);
 808
 809 char *add_xterm_umid(char *base)
 810 {
 811         char *umid, *title;
 812         int len;
 813
 814         umid = get_umid(1);
 815         if(umid == NULL)
 816                 return base;
 817
 818         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 819         title = kmalloc(len, GFP_KERNEL);
 820         if(title == NULL){
 821                 printk("Failed to allocate buffer for xterm title\n");
 822                 return base;
 823         }
 824
 825         snprintf(title, len, "%s (%s)", base, umid);
 826         return title;
 827 }