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