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;
 285
 286         if (input)
 287                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 288                                      line_interrupt, IRQF_SHARED,
 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, IRQF_SHARED,
 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         if (line->port.count) {
 386                 *error_out = "Device is already open";
 387                 goto out;
 388         }
 389
 390         if (!strcmp(init, "none")) {
 391                 if (line->valid) {
 392                         line->valid = 0;
 393                         kfree(line->init_str);
 394                         tty_unregister_device(driver, n);
 395                         parse_chan_pair(NULL, line, n, opts, error_out);
 396                         err = 0;
 397                 }
 398         } else {
 399                 char *new = kstrdup(init, GFP_KERNEL);
 400                 if (!new) {
 401                         *error_out = "Failed to allocate memory";
 402                         return -ENOMEM;
 403                 }
 404                 if (line->valid) {
 405                         tty_unregister_device(driver, n);
 406                         kfree(line->init_str);
 407                 }
 408                 line->init_str = new;
 409                 line->valid = 1;
 410                 err = parse_chan_pair(new, line, n, opts, error_out);
 411                 if (!err) {
 412                         struct device *d = tty_register_device(driver, n, NULL);
 413                         if (IS_ERR(d)) {
 414                                 *error_out = "Failed to register device";
 415                                 err = PTR_ERR(d);
 416                                 parse_chan_pair(NULL, line, n, opts, error_out);
 417                         }
 418                 }
 419                 if (err) {
 420                         line->init_str = NULL;
 421                         line->valid = 0;
 422                         kfree(new);
 423                 }
 424         }
 425 out:
 426         return err;
 427 }
 428
 429 /*
 430  * Common setup code for both startup command line and mconsole initialization.
 431  * @lines contains the array (of size @num) to modify;
 432  * @init is the setup string;
 433  * @error_out is an error string in the case of failure;
 434  */
 435
 436 int line_setup(char **conf, unsigned int num, char **def,
 437                char *init, char *name)
 438 {
 439         char *error;
 440
 441         if (*init == '=') {
 442                 /*
 443                  * We said con=/ssl= instead of con#=, so we are configuring all
 444                  * consoles at once.
 445                  */
 446                 *def = init + 1;
 447         } else {
 448                 char *end;
 449                 unsigned n = simple_strtoul(init, &end, 0);
 450
 451                 if (*end != '=') {
 452                         error = "Couldn't parse device number";
 453                         goto out;
 454                 }
 455                 if (n >= num) {
 456                         error = "Device number out of range";
 457                         goto out;
 458                 }
 459                 conf[n] = end + 1;
 460         }
 461         return 0;
 462
 463 out:
 464         printk(KERN_ERR "Failed to set up %s with "
 465                "configuration string \"%s\" : %s\n", name, init, error);
 466         return -EINVAL;
 467 }
 468
 469 int line_config(struct line *lines, unsigned int num, char *str,
 470                 const struct chan_opts *opts, char **error_out)
 471 {
 472         char *end;
 473         int n;
 474
 475         if (*str == '=') {
 476                 *error_out = "Can't configure all devices from mconsole";
 477                 return -EINVAL;
 478         }
 479
 480         n = simple_strtoul(str, &end, 0);
 481         if (*end++ != '=') {
 482                 *error_out = "Couldn't parse device number";
 483                 return -EINVAL;
 484         }
 485         if (n >= num) {
 486                 *error_out = "Device number out of range";
 487                 return -EINVAL;
 488         }
 489
 490         return setup_one_line(lines, n, end, opts, error_out);
 491 }
 492
 493 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 494                     int size, char **error_out)
 495 {
 496         struct line *line;
 497         char *end;
 498         int dev, n = 0;
 499
 500         dev = simple_strtoul(name, &end, 0);
 501         if ((*end != '\0') || (end == name)) {
 502                 *error_out = "line_get_config failed to parse device number";
 503                 return 0;
 504         }
 505
 506         if ((dev < 0) || (dev >= num)) {
 507                 *error_out = "device number out of range";
 508                 return 0;
 509         }
 510
 511         line = &lines[dev];
 512
 513         if (!line->valid)
 514                 CONFIG_CHUNK(str, size, n, "none", 1);
 515         else {
 516                 struct tty_struct *tty = tty_port_tty_get(&line->port);
 517                 if (tty == NULL) {
 518                         CONFIG_CHUNK(str, size, n, line->init_str, 1);
 519                 } else {
 520                         n = chan_config_string(line, str, size, error_out);
 521                         tty_kref_put(tty);
 522                 }
 523         }
 524
 525         return n;
 526 }
 527
 528 int line_id(char **str, int *start_out, int *end_out)
 529 {
 530         char *end;
 531         int n;
 532
 533         n = simple_strtoul(*str, &end, 0);
 534         if ((*end != '\0') || (end == *str))
 535                 return -1;
 536
 537         *str = end;
 538         *start_out = n;
 539         *end_out = n;
 540         return n;
 541 }
 542
 543 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 544 {
 545         if (n >= num) {
 546                 *error_out = "Device number out of range";
 547                 return -EINVAL;
 548         }
 549         return setup_one_line(lines, n, "none", NULL, error_out);
 550 }
 551
 552 int register_lines(struct line_driver *line_driver,
 553                    const struct tty_operations *ops,
 554                    struct line *lines, int nlines)
 555 {
 556         struct tty_driver *driver = alloc_tty_driver(nlines);
 557         int err;
 558         int i;
 559
 560         if (!driver)
 561                 return -ENOMEM;
 562
 563         driver->driver_name = line_driver->name;
 564         driver->name = line_driver->device_name;
 565         driver->major = line_driver->major;
 566         driver->minor_start = line_driver->minor_start;
 567         driver->type = line_driver->type;
 568         driver->subtype = line_driver->subtype;
 569         driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 570         driver->init_termios = tty_std_termios;
 571
 572         for (i = 0; i < nlines; i++) {
 573                 tty_port_init(&lines[i].port);
 574                 lines[i].port.ops = &line_port_ops;
 575                 spin_lock_init(&lines[i].lock);
 576                 lines[i].driver = line_driver;
 577                 INIT_LIST_HEAD(&lines[i].chan_list);
 578         }
 579         tty_set_operations(driver, ops);
 580
 581         err = tty_register_driver(driver);
 582         if (err) {
 583                 printk(KERN_ERR "register_lines : can't register %s driver\n",
 584                        line_driver->name);
 585                 put_tty_driver(driver);
 586                 return err;
 587         }
 588
 589         line_driver->driver = driver;
 590         mconsole_register_dev(&line_driver->mc);
 591         return 0;
 592 }
 593
 594 static DEFINE_SPINLOCK(winch_handler_lock);
 595 static LIST_HEAD(winch_handlers);
 596
 597 struct winch {
 598         struct list_head list;
 599         int fd;
 600         int tty_fd;
 601         int pid;
 602         struct tty_struct *tty;
 603         unsigned long stack;
 604         struct work_struct work;
 605 };
 606
 607 static void __free_winch(struct work_struct *work)
 608 {
 609         struct winch *winch = container_of(work, struct winch, work);
 610         um_free_irq(WINCH_IRQ, winch);
 611
 612         if (winch->pid != -1)
 613                 os_kill_process(winch->pid, 1);
 614         if (winch->stack != 0)
 615                 free_stack(winch->stack, 0);
 616         kfree(winch);
 617 }
 618
 619 static void free_winch(struct winch *winch)
 620 {
 621         int fd = winch->fd;
 622         winch->fd = -1;
 623         if (fd != -1)
 624                 os_close_file(fd);
 625         list_del(&winch->list);
 626         __free_winch(&winch->work);
 627 }
 628
 629 static irqreturn_t winch_interrupt(int irq, void *data)
 630 {
 631         struct winch *winch = data;
 632         struct tty_struct *tty;
 633         struct line *line;
 634         int fd = winch->fd;
 635         int err;
 636         char c;
 637
 638         if (fd != -1) {
 639                 err = generic_read(fd, &c, NULL);
 640                 if (err < 0) {
 641                         if (err != -EAGAIN) {
 642                                 winch->fd = -1;
 643                                 list_del(&winch->list);
 644                                 os_close_file(fd);
 645                                 printk(KERN_ERR "winch_interrupt : "
 646                                        "read failed, errno = %d\n", -err);
 647                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
 648                                        "support\n", winch->tty_fd);
 649                                 INIT_WORK(&winch->work, __free_winch);
 650                                 schedule_work(&winch->work);
 651                                 return IRQ_HANDLED;
 652                         }
 653                         goto out;
 654                 }
 655         }
 656         tty = winch->tty;
 657         if (tty != NULL) {
 658                 line = tty->driver_data;
 659                 if (line != NULL) {
 660                         chan_window_size(line, &tty->winsize.ws_row,
 661                                          &tty->winsize.ws_col);
 662                         kill_pgrp(tty->pgrp, SIGWINCH, 1);
 663                 }
 664         }
 665  out:
 666         if (winch->fd != -1)
 667                 reactivate_fd(winch->fd, WINCH_IRQ);
 668         return IRQ_HANDLED;
 669 }
 670
 671 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
 672                         unsigned long stack)
 673 {
 674         struct winch *winch;
 675
 676         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 677         if (winch == NULL) {
 678                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
 679                 goto cleanup;
 680         }
 681
 682         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 683                                    .fd          = fd,
 684                                    .tty_fd      = tty_fd,
 685                                    .pid         = pid,
 686                                    .tty         = tty,
 687                                    .stack       = stack });
 688
 689         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 690                            IRQF_SHARED, "winch", winch) < 0) {
 691                 printk(KERN_ERR "register_winch_irq - failed to register "
 692                        "IRQ\n");
 693                 goto out_free;
 694         }
 695
 696         spin_lock(&winch_handler_lock);
 697         list_add(&winch->list, &winch_handlers);
 698         spin_unlock(&winch_handler_lock);
 699
 700         return;
 701
 702  out_free:
 703         kfree(winch);
 704  cleanup:
 705         os_kill_process(pid, 1);
 706         os_close_file(fd);
 707         if (stack != 0)
 708                 free_stack(stack, 0);
 709 }
 710
 711 static void unregister_winch(struct tty_struct *tty)
 712 {
 713         struct list_head *ele, *next;
 714         struct winch *winch;
 715
 716         spin_lock(&winch_handler_lock);
 717
 718         list_for_each_safe(ele, next, &winch_handlers) {
 719                 winch = list_entry(ele, struct winch, list);
 720                 if (winch->tty == tty) {
 721                         free_winch(winch);
 722                         break;
 723                 }
 724         }
 725         spin_unlock(&winch_handler_lock);
 726 }
 727
 728 static void winch_cleanup(void)
 729 {
 730         struct list_head *ele, *next;
 731         struct winch *winch;
 732
 733         spin_lock(&winch_handler_lock);
 734
 735         list_for_each_safe(ele, next, &winch_handlers) {
 736                 winch = list_entry(ele, struct winch, list);
 737                 free_winch(winch);
 738         }
 739
 740         spin_unlock(&winch_handler_lock);
 741 }
 742 __uml_exitcall(winch_cleanup);
 743
 744 char *add_xterm_umid(char *base)
 745 {
 746         char *umid, *title;
 747         int len;
 748
 749         umid = get_umid();
 750         if (*umid == '\0')
 751                 return base;
 752
 753         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 754         title = kmalloc(len, GFP_KERNEL);
 755         if (title == NULL) {
 756                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
 757                 return base;
 758         }
 759
 760         snprintf(title, len, "%s (%s)", base, umid);
 761         return title;
 762 }