Pileus Git - ~andy/linux/blob - arch/um/drivers/line.c

   1 /*
   2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/irqreturn.h"
   7 #include "linux/kd.h"
   8 #include "linux/sched.h"
   9 #include "linux/slab.h"
  10 #include "chan.h"
  11 #include "irq_kern.h"
  12 #include "irq_user.h"
  13 #include "kern_util.h"
  14 #include "os.h"
  15
  16 #define LINE_BUFSIZE 4096
  17
  18 static irqreturn_t line_interrupt(int irq, void *data)
  19 {
  20         struct chan *chan = data;
  21         struct line *line = chan->line;
  22         struct tty_struct *tty = tty_port_tty_get(&line->port);
  23
  24         if (line)
  25                 chan_interrupt(line, tty, irq);
  26         tty_kref_put(tty);
  27         return IRQ_HANDLED;
  28 }
  29
  30 /*
  31  * Returns the free space inside the ring buffer of this line.
  32  *
  33  * Should be called while holding line->lock (this does not modify data).
  34  */
  35 static int write_room(struct line *line)
  36 {
  37         int n;
  38
  39         if (line->buffer == NULL)
  40                 return LINE_BUFSIZE - 1;
  41
  42         /* This is for the case where the buffer is wrapped! */
  43         n = line->head - line->tail;
  44
  45         if (n <= 0)
  46                 n += LINE_BUFSIZE; /* The other case */
  47         return n - 1;
  48 }
  49
  50 int line_write_room(struct tty_struct *tty)
  51 {
  52         struct line *line = tty->driver_data;
  53         unsigned long flags;
  54         int room;
  55
  56         spin_lock_irqsave(&line->lock, flags);
  57         room = write_room(line);
  58         spin_unlock_irqrestore(&line->lock, flags);
  59
  60         return room;
  61 }
  62
  63 int line_chars_in_buffer(struct tty_struct *tty)
  64 {
  65         struct line *line = tty->driver_data;
  66         unsigned long flags;
  67         int ret;
  68
  69         spin_lock_irqsave(&line->lock, flags);
  70         /* write_room subtracts 1 for the needed NULL, so we readd it.*/
  71         ret = LINE_BUFSIZE - (write_room(line) + 1);
  72         spin_unlock_irqrestore(&line->lock, flags);
  73
  74         return ret;
  75 }
  76
  77 /*
  78  * This copies the content of buf into the circular buffer associated with
  79  * this line.
  80  * The return value is the number of characters actually copied, i.e. the ones
  81  * for which there was space: this function is not supposed to ever flush out
  82  * the circular buffer.
  83  *
  84  * Must be called while holding line->lock!
  85  */
  86 static int buffer_data(struct line *line, const char *buf, int len)
  87 {
  88         int end, room;
  89
  90         if (line->buffer == NULL) {
  91                 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
  92                 if (line->buffer == NULL) {
  93                         printk(KERN_ERR "buffer_data - atomic allocation "
  94                                "failed\n");
  95                         return 0;
  96                 }
  97                 line->head = line->buffer;
  98                 line->tail = line->buffer;
  99         }
 100
 101         room = write_room(line);
 102         len = (len > room) ? room : len;
 103
 104         end = line->buffer + LINE_BUFSIZE - line->tail;
 105
 106         if (len < end) {
 107                 memcpy(line->tail, buf, len);
 108                 line->tail += len;
 109         }
 110         else {
 111                 /* The circular buffer is wrapping */
 112                 memcpy(line->tail, buf, end);
 113                 buf += end;
 114                 memcpy(line->buffer, buf, len - end);
 115                 line->tail = line->buffer + len - end;
 116         }
 117
 118         return len;
 119 }
 120
 121 /*
 122  * Flushes the ring buffer to the output channels. That is, write_chan is
 123  * called, passing it line->head as buffer, and an appropriate count.
 124  *
 125  * On exit, returns 1 when the buffer is empty,
 126  * 0 when the buffer is not empty on exit,
 127  * and -errno when an error occurred.
 128  *
 129  * Must be called while holding line->lock!*/
 130 static int flush_buffer(struct line *line)
 131 {
 132         int n, count;
 133
 134         if ((line->buffer == NULL) || (line->head == line->tail))
 135                 return 1;
 136
 137         if (line->tail < line->head) {
 138                 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
 139                 count = line->buffer + LINE_BUFSIZE - line->head;
 140
 141                 n = write_chan(line->chan_out, line->head, count,
 142                                line->driver->write_irq);
 143                 if (n < 0)
 144                         return n;
 145                 if (n == count) {
 146                         /*
 147                          * We have flushed from ->head to buffer end, now we
 148                          * must flush only from the beginning to ->tail.
 149                          */
 150                         line->head = line->buffer;
 151                 } else {
 152                         line->head += n;
 153                         return 0;
 154                 }
 155         }
 156
 157         count = line->tail - line->head;
 158         n = write_chan(line->chan_out, line->head, count,
 159                        line->driver->write_irq);
 160
 161         if (n < 0)
 162                 return n;
 163
 164         line->head += n;
 165         return line->head == line->tail;
 166 }
 167
 168 void line_flush_buffer(struct tty_struct *tty)
 169 {
 170         struct line *line = tty->driver_data;
 171         unsigned long flags;
 172
 173         spin_lock_irqsave(&line->lock, flags);
 174         flush_buffer(line);
 175         spin_unlock_irqrestore(&line->lock, flags);
 176 }
 177
 178 /*
 179  * We map both ->flush_chars and ->put_char (which go in pair) onto
 180  * ->flush_buffer and ->write. Hope it's not that bad.
 181  */
 182 void line_flush_chars(struct tty_struct *tty)
 183 {
 184         line_flush_buffer(tty);
 185 }
 186
 187 int line_put_char(struct tty_struct *tty, unsigned char ch)
 188 {
 189         return line_write(tty, &ch, sizeof(ch));
 190 }
 191
 192 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
 193 {
 194         struct line *line = tty->driver_data;
 195         unsigned long flags;
 196         int n, ret = 0;
 197
 198         spin_lock_irqsave(&line->lock, flags);
 199         if (line->head != line->tail)
 200                 ret = buffer_data(line, buf, len);
 201         else {
 202                 n = write_chan(line->chan_out, buf, len,
 203                                line->driver->write_irq);
 204                 if (n < 0) {
 205                         ret = n;
 206                         goto out_up;
 207                 }
 208
 209                 len -= n;
 210                 ret += n;
 211                 if (len > 0)
 212                         ret += buffer_data(line, buf + n, len);
 213         }
 214 out_up:
 215         spin_unlock_irqrestore(&line->lock, flags);
 216         return ret;
 217 }
 218
 219 void line_set_termios(struct tty_struct *tty, struct ktermios * old)
 220 {
 221         /* nothing */
 222 }
 223
 224 void line_throttle(struct tty_struct *tty)
 225 {
 226         struct line *line = tty->driver_data;
 227
 228         deactivate_chan(line->chan_in, line->driver->read_irq);
 229         line->throttled = 1;
 230 }
 231
 232 void line_unthrottle(struct tty_struct *tty)
 233 {
 234         struct line *line = tty->driver_data;
 235
 236         line->throttled = 0;
 237         chan_interrupt(line, tty, line->driver->read_irq);
 238
 239         /*
 240          * Maybe there is enough stuff pending that calling the interrupt
 241          * throttles us again.  In this case, line->throttled will be 1
 242          * again and we shouldn't turn the interrupt back on.
 243          */
 244         if (!line->throttled)
 245                 reactivate_chan(line->chan_in, line->driver->read_irq);
 246 }
 247
 248 static irqreturn_t line_write_interrupt(int irq, void *data)
 249 {
 250         struct chan *chan = data;
 251         struct line *line = chan->line;
 252         struct tty_struct *tty;
 253         int err;
 254
 255         /*
 256          * Interrupts are disabled here because genirq keep irqs disabled when
 257          * calling the action handler.
 258          */
 259
 260         spin_lock(&line->lock);
 261         err = flush_buffer(line);
 262         if (err == 0) {
 263                 spin_unlock(&line->lock);
 264                 return IRQ_NONE;
 265         } else if (err < 0) {
 266                 line->head = line->buffer;
 267                 line->tail = line->buffer;
 268         }
 269         spin_unlock(&line->lock);
 270
 271         tty = tty_port_tty_get(&line->port);
 272         if (tty == NULL)
 273                 return IRQ_NONE;
 274
 275         tty_wakeup(tty);
 276         tty_kref_put(tty);
 277
 278         return IRQ_HANDLED;
 279 }
 280
 281 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 282 {
 283         const struct line_driver *driver = line->driver;
 284         int err = 0, flags = IRQF_SHARED | IRQF_SAMPLE_RANDOM;
 285
 286         if (input)
 287                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 288                                        line_interrupt, flags,
 289                                        driver->read_irq_name, data);
 290         if (err)
 291                 return err;
 292         if (output)
 293                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 294                                         line_write_interrupt, flags,
 295                                         driver->write_irq_name, data);
 296         return err;
 297 }
 298
 299 static int line_activate(struct tty_port *port, struct tty_struct *tty)
 300 {
 301         int ret;
 302         struct line *line = tty->driver_data;
 303
 304         ret = enable_chan(line);
 305         if (ret)
 306                 return ret;
 307
 308         if (!line->sigio) {
 309                 chan_enable_winch(line->chan_out, tty);
 310                 line->sigio = 1;
 311         }
 312
 313         chan_window_size(line, &tty->winsize.ws_row,
 314                 &tty->winsize.ws_col);
 315
 316         return 0;
 317 }
 318
 319 static const struct tty_port_operations line_port_ops = {
 320         .activate = line_activate,
 321 };
 322
 323 int line_open(struct tty_struct *tty, struct file *filp)
 324 {
 325         struct line *line = tty->driver_data;
 326
 327         return tty_port_open(&line->port, tty, filp);
 328 }
 329
 330 int line_install(struct tty_driver *driver, struct tty_struct *tty,
 331                  struct line *line)
 332 {
 333         int ret;
 334
 335         ret = tty_standard_install(driver, tty);
 336         if (ret)
 337                 return ret;
 338
 339         tty->driver_data = line;
 340
 341         return 0;
 342 }
 343
 344 static void unregister_winch(struct tty_struct *tty);
 345
 346 void line_cleanup(struct tty_struct *tty)
 347 {
 348         struct line *line = tty->driver_data;
 349
 350         if (line->sigio) {
 351                 unregister_winch(tty);
 352                 line->sigio = 0;
 353         }
 354 }
 355
 356 void line_close(struct tty_struct *tty, struct file * filp)
 357 {
 358         struct line *line = tty->driver_data;
 359
 360         tty_port_close(&line->port, tty, filp);
 361 }
 362
 363 void line_hangup(struct tty_struct *tty)
 364 {
 365         struct line *line = tty->driver_data;
 366
 367         tty_port_hangup(&line->port);
 368 }
 369
 370 void close_lines(struct line *lines, int nlines)
 371 {
 372         int i;
 373
 374         for(i = 0; i < nlines; i++)
 375                 close_chan(&lines[i]);
 376 }
 377
 378 int setup_one_line(struct line *lines, int n, char *init,
 379                    const struct chan_opts *opts, char **error_out)
 380 {
 381         struct line *line = &lines[n];
 382         struct tty_driver *driver = line->driver->driver;
 383         int err = -EINVAL;
 384
 385         mutex_lock(&line->count_lock);
 386
 387         if (line->port.count) {
 388                 *error_out = "Device is already open";
 389                 goto out;
 390         }
 391
 392         if (!strcmp(init, "none")) {
 393                 if (line->valid) {
 394                         line->valid = 0;
 395                         kfree(line->init_str);
 396                         tty_unregister_device(driver, n);
 397                         parse_chan_pair(NULL, line, n, opts, error_out);
 398                         err = 0;
 399                 }
 400         } else {
 401                 char *new = kstrdup(init, GFP_KERNEL);
 402                 if (!new) {
 403                         *error_out = "Failed to allocate memory";
 404                         return -ENOMEM;
 405                 }
 406                 if (line->valid) {
 407                         tty_unregister_device(driver, n);
 408                         kfree(line->init_str);
 409                 }
 410                 line->init_str = new;
 411                 line->valid = 1;
 412                 err = parse_chan_pair(new, line, n, opts, error_out);
 413                 if (!err) {
 414                         struct device *d = tty_register_device(driver, n, NULL);
 415                         if (IS_ERR(d)) {
 416                                 *error_out = "Failed to register device";
 417                                 err = PTR_ERR(d);
 418                                 parse_chan_pair(NULL, line, n, opts, error_out);
 419                         }
 420                 }
 421                 if (err) {
 422                         line->init_str = NULL;
 423                         line->valid = 0;
 424                         kfree(new);
 425                 }
 426         }
 427 out:
 428         mutex_unlock(&line->count_lock);
 429         return err;
 430 }
 431
 432 /*
 433  * Common setup code for both startup command line and mconsole initialization.
 434  * @lines contains the array (of size @num) to modify;
 435  * @init is the setup string;
 436  * @error_out is an error string in the case of failure;
 437  */
 438
 439 int line_setup(char **conf, unsigned int num, char **def,
 440                char *init, char *name)
 441 {
 442         char *error;
 443
 444         if (*init == '=') {
 445                 /*
 446                  * We said con=/ssl= instead of con#=, so we are configuring all
 447                  * consoles at once.
 448                  */
 449                 *def = init + 1;
 450         } else {
 451                 char *end;
 452                 unsigned n = simple_strtoul(init, &end, 0);
 453
 454                 if (*end != '=') {
 455                         error = "Couldn't parse device number";
 456                         goto out;
 457                 }
 458                 if (n >= num) {
 459                         error = "Device number out of range";
 460                         goto out;
 461                 }
 462                 conf[n] = end + 1;
 463         }
 464         return 0;
 465
 466 out:
 467         printk(KERN_ERR "Failed to set up %s with "
 468                "configuration string \"%s\" : %s\n", name, init, error);
 469         return -EINVAL;
 470 }
 471
 472 int line_config(struct line *lines, unsigned int num, char *str,
 473                 const struct chan_opts *opts, char **error_out)
 474 {
 475         char *end;
 476         int n;
 477
 478         if (*str == '=') {
 479                 *error_out = "Can't configure all devices from mconsole";
 480                 return -EINVAL;
 481         }
 482
 483         n = simple_strtoul(str, &end, 0);
 484         if (*end++ != '=') {
 485                 *error_out = "Couldn't parse device number";
 486                 return -EINVAL;
 487         }
 488         if (n >= num) {
 489                 *error_out = "Device number out of range";
 490                 return -EINVAL;
 491         }
 492
 493         return setup_one_line(lines, n, end, opts, error_out);
 494 }
 495
 496 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 497                     int size, char **error_out)
 498 {
 499         struct line *line;
 500         char *end;
 501         int dev, n = 0;
 502
 503         dev = simple_strtoul(name, &end, 0);
 504         if ((*end != '\0') || (end == name)) {
 505                 *error_out = "line_get_config failed to parse device number";
 506                 return 0;
 507         }
 508
 509         if ((dev < 0) || (dev >= num)) {
 510                 *error_out = "device number out of range";
 511                 return 0;
 512         }
 513
 514         line = &lines[dev];
 515
 516         mutex_lock(&line->count_lock);
 517         if (!line->valid)
 518                 CONFIG_CHUNK(str, size, n, "none", 1);
 519         else {
 520                 struct tty_struct *tty = tty_port_tty_get(&line->port);
 521                 if (tty == NULL) {
 522                         CONFIG_CHUNK(str, size, n, line->init_str, 1);
 523                 } else {
 524                         n = chan_config_string(line, str, size, error_out);
 525                         tty_kref_put(tty);
 526                 }
 527         }
 528         mutex_unlock(&line->count_lock);
 529
 530         return n;
 531 }
 532
 533 int line_id(char **str, int *start_out, int *end_out)
 534 {
 535         char *end;
 536         int n;
 537
 538         n = simple_strtoul(*str, &end, 0);
 539         if ((*end != '\0') || (end == *str))
 540                 return -1;
 541
 542         *str = end;
 543         *start_out = n;
 544         *end_out = n;
 545         return n;
 546 }
 547
 548 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 549 {
 550         if (n >= num) {
 551                 *error_out = "Device number out of range";
 552                 return -EINVAL;
 553         }
 554         return setup_one_line(lines, n, "none", NULL, error_out);
 555 }
 556
 557 int register_lines(struct line_driver *line_driver,
 558                    const struct tty_operations *ops,
 559                    struct line *lines, int nlines)
 560 {
 561         struct tty_driver *driver = alloc_tty_driver(nlines);
 562         int err;
 563         int i;
 564
 565         if (!driver)
 566                 return -ENOMEM;
 567
 568         driver->driver_name = line_driver->name;
 569         driver->name = line_driver->device_name;
 570         driver->major = line_driver->major;
 571         driver->minor_start = line_driver->minor_start;
 572         driver->type = line_driver->type;
 573         driver->subtype = line_driver->subtype;
 574         driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 575         driver->init_termios = tty_std_termios;
 576
 577         for (i = 0; i < nlines; i++) {
 578                 tty_port_init(&lines[i].port);
 579                 lines[i].port.ops = &line_port_ops;
 580                 spin_lock_init(&lines[i].lock);
 581                 mutex_init(&lines[i].count_lock);
 582                 lines[i].driver = line_driver;
 583                 INIT_LIST_HEAD(&lines[i].chan_list);
 584         }
 585         tty_set_operations(driver, ops);
 586
 587         err = tty_register_driver(driver);
 588         if (err) {
 589                 printk(KERN_ERR "register_lines : can't register %s driver\n",
 590                        line_driver->name);
 591                 put_tty_driver(driver);
 592                 return err;
 593         }
 594
 595         line_driver->driver = driver;
 596         mconsole_register_dev(&line_driver->mc);
 597         return 0;
 598 }
 599
 600 static DEFINE_SPINLOCK(winch_handler_lock);
 601 static LIST_HEAD(winch_handlers);
 602
 603 struct winch {
 604         struct list_head list;
 605         int fd;
 606         int tty_fd;
 607         int pid;
 608         struct tty_struct *tty;
 609         unsigned long stack;
 610         struct work_struct work;
 611 };
 612
 613 static void __free_winch(struct work_struct *work)
 614 {
 615         struct winch *winch = container_of(work, struct winch, work);
 616         um_free_irq(WINCH_IRQ, winch);
 617
 618         if (winch->pid != -1)
 619                 os_kill_process(winch->pid, 1);
 620         if (winch->stack != 0)
 621                 free_stack(winch->stack, 0);
 622         kfree(winch);
 623 }
 624
 625 static void free_winch(struct winch *winch)
 626 {
 627         int fd = winch->fd;
 628         winch->fd = -1;
 629         if (fd != -1)
 630                 os_close_file(fd);
 631         list_del(&winch->list);
 632         __free_winch(&winch->work);
 633 }
 634
 635 static irqreturn_t winch_interrupt(int irq, void *data)
 636 {
 637         struct winch *winch = data;
 638         struct tty_struct *tty;
 639         struct line *line;
 640         int fd = winch->fd;
 641         int err;
 642         char c;
 643
 644         if (fd != -1) {
 645                 err = generic_read(fd, &c, NULL);
 646                 if (err < 0) {
 647                         if (err != -EAGAIN) {
 648                                 winch->fd = -1;
 649                                 list_del(&winch->list);
 650                                 os_close_file(fd);
 651                                 printk(KERN_ERR "winch_interrupt : "
 652                                        "read failed, errno = %d\n", -err);
 653                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
 654                                        "support\n", winch->tty_fd);
 655                                 INIT_WORK(&winch->work, __free_winch);
 656                                 schedule_work(&winch->work);
 657                                 return IRQ_HANDLED;
 658                         }
 659                         goto out;
 660                 }
 661         }
 662         tty = winch->tty;
 663         if (tty != NULL) {
 664                 line = tty->driver_data;
 665                 if (line != NULL) {
 666                         chan_window_size(line, &tty->winsize.ws_row,
 667                                          &tty->winsize.ws_col);
 668                         kill_pgrp(tty->pgrp, SIGWINCH, 1);
 669                 }
 670         }
 671  out:
 672         if (winch->fd != -1)
 673                 reactivate_fd(winch->fd, WINCH_IRQ);
 674         return IRQ_HANDLED;
 675 }
 676
 677 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
 678                         unsigned long stack)
 679 {
 680         struct winch *winch;
 681
 682         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 683         if (winch == NULL) {
 684                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
 685                 goto cleanup;
 686         }
 687
 688         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 689                                    .fd          = fd,
 690                                    .tty_fd      = tty_fd,
 691                                    .pid         = pid,
 692                                    .tty         = tty,
 693                                    .stack       = stack });
 694
 695         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 696                            IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 697                            "winch", winch) < 0) {
 698                 printk(KERN_ERR "register_winch_irq - failed to register "
 699                        "IRQ\n");
 700                 goto out_free;
 701         }
 702
 703         spin_lock(&winch_handler_lock);
 704         list_add(&winch->list, &winch_handlers);
 705         spin_unlock(&winch_handler_lock);
 706
 707         return;
 708
 709  out_free:
 710         kfree(winch);
 711  cleanup:
 712         os_kill_process(pid, 1);
 713         os_close_file(fd);
 714         if (stack != 0)
 715                 free_stack(stack, 0);
 716 }
 717
 718 static void unregister_winch(struct tty_struct *tty)
 719 {
 720         struct list_head *ele, *next;
 721         struct winch *winch;
 722
 723         spin_lock(&winch_handler_lock);
 724
 725         list_for_each_safe(ele, next, &winch_handlers) {
 726                 winch = list_entry(ele, struct winch, list);
 727                 if (winch->tty == tty) {
 728                         free_winch(winch);
 729                         break;
 730                 }
 731         }
 732         spin_unlock(&winch_handler_lock);
 733 }
 734
 735 static void winch_cleanup(void)
 736 {
 737         struct list_head *ele, *next;
 738         struct winch *winch;
 739
 740         spin_lock(&winch_handler_lock);
 741
 742         list_for_each_safe(ele, next, &winch_handlers) {
 743                 winch = list_entry(ele, struct winch, list);
 744                 free_winch(winch);
 745         }
 746
 747         spin_unlock(&winch_handler_lock);
 748 }
 749 __uml_exitcall(winch_cleanup);
 750
 751 char *add_xterm_umid(char *base)
 752 {
 753         char *umid, *title;
 754         int len;
 755
 756         umid = get_umid();
 757         if (*umid == '\0')
 758                 return base;
 759
 760         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 761         title = kmalloc(len, GFP_KERNEL);
 762         if (title == NULL) {
 763                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
 764                 return base;
 765         }
 766
 767         snprintf(title, len, "%s (%s)", base, umid);
 768         return title;
 769 }