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         struct tty_struct *tty;
 252         int err;
 253
 254         /*
 255          * Interrupts are disabled here because genirq keep irqs disabled when
 256          * calling the action handler.
 257          */
 258
 259         spin_lock(&line->lock);
 260         err = flush_buffer(line);
 261         if (err == 0) {
 262                 spin_unlock(&line->lock);
 263                 return IRQ_NONE;
 264         } else if (err < 0) {
 265                 line->head = line->buffer;
 266                 line->tail = line->buffer;
 267         }
 268         spin_unlock(&line->lock);
 269
 270         tty = tty_port_tty_get(&line->port);
 271         if (tty == NULL)
 272                 return IRQ_NONE;
 273
 274         tty_wakeup(tty);
 275         tty_kref_put(tty);
 276
 277         return IRQ_HANDLED;
 278 }
 279
 280 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 281 {
 282         const struct line_driver *driver = line->driver;
 283         int err = 0;
 284
 285         if (input)
 286                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 287                                      line_interrupt, IRQF_SHARED,
 288                                      driver->read_irq_name, data);
 289         if (err)
 290                 return err;
 291         if (output)
 292                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 293                                      line_write_interrupt, IRQF_SHARED,
 294                                      driver->write_irq_name, data);
 295         return err;
 296 }
 297
 298 static int line_activate(struct tty_port *port, struct tty_struct *tty)
 299 {
 300         int ret;
 301         struct line *line = tty->driver_data;
 302
 303         ret = enable_chan(line);
 304         if (ret)
 305                 return ret;
 306
 307         if (!line->sigio) {
 308                 chan_enable_winch(line->chan_out, tty);
 309                 line->sigio = 1;
 310         }
 311
 312         chan_window_size(line, &tty->winsize.ws_row,
 313                 &tty->winsize.ws_col);
 314
 315         return 0;
 316 }
 317
 318 static const struct tty_port_operations line_port_ops = {
 319         .activate = line_activate,
 320 };
 321
 322 int line_open(struct tty_struct *tty, struct file *filp)
 323 {
 324         struct line *line = tty->driver_data;
 325
 326         return tty_port_open(&line->port, tty, filp);
 327 }
 328
 329 int line_install(struct tty_driver *driver, struct tty_struct *tty,
 330                  struct line *line)
 331 {
 332         int ret;
 333
 334         ret = tty_standard_install(driver, tty);
 335         if (ret)
 336                 return ret;
 337
 338         tty->driver_data = line;
 339
 340         return 0;
 341 }
 342
 343 static void unregister_winch(struct tty_struct *tty);
 344
 345 void line_cleanup(struct tty_struct *tty)
 346 {
 347         struct line *line = tty->driver_data;
 348
 349         if (line->sigio) {
 350                 unregister_winch(tty);
 351                 line->sigio = 0;
 352         }
 353 }
 354
 355 void line_close(struct tty_struct *tty, struct file * filp)
 356 {
 357         struct line *line = tty->driver_data;
 358
 359         tty_port_close(&line->port, tty, filp);
 360 }
 361
 362 void line_hangup(struct tty_struct *tty)
 363 {
 364         struct line *line = tty->driver_data;
 365
 366         tty_port_hangup(&line->port);
 367 }
 368
 369 void close_lines(struct line *lines, int nlines)
 370 {
 371         int i;
 372
 373         for(i = 0; i < nlines; i++)
 374                 close_chan(&lines[i]);
 375 }
 376
 377 int setup_one_line(struct line *lines, int n, char *init,
 378                    const struct chan_opts *opts, char **error_out)
 379 {
 380         struct line *line = &lines[n];
 381         struct tty_driver *driver = line->driver->driver;
 382         int err = -EINVAL;
 383
 384         if (line->port.count) {
 385                 *error_out = "Device is already open";
 386                 goto out;
 387         }
 388
 389         if (!strcmp(init, "none")) {
 390                 if (line->valid) {
 391                         line->valid = 0;
 392                         kfree(line->init_str);
 393                         tty_unregister_device(driver, n);
 394                         parse_chan_pair(NULL, line, n, opts, error_out);
 395                         err = 0;
 396                 }
 397         } else {
 398                 char *new = kstrdup(init, GFP_KERNEL);
 399                 if (!new) {
 400                         *error_out = "Failed to allocate memory";
 401                         return -ENOMEM;
 402                 }
 403                 if (line->valid) {
 404                         tty_unregister_device(driver, n);
 405                         kfree(line->init_str);
 406                 }
 407                 line->init_str = new;
 408                 line->valid = 1;
 409                 err = parse_chan_pair(new, line, n, opts, error_out);
 410                 if (!err) {
 411                         struct device *d = tty_port_register_device(&line->port,
 412                                         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                 for (i = 0; i < nlines; i++)
 587                         tty_port_destroy(&lines[i].port);
 588                 return err;
 589         }
 590
 591         line_driver->driver = driver;
 592         mconsole_register_dev(&line_driver->mc);
 593         return 0;
 594 }
 595
 596 static DEFINE_SPINLOCK(winch_handler_lock);
 597 static LIST_HEAD(winch_handlers);
 598
 599 struct winch {
 600         struct list_head list;
 601         int fd;
 602         int tty_fd;
 603         int pid;
 604         struct tty_struct *tty;
 605         unsigned long stack;
 606         struct work_struct work;
 607 };
 608
 609 static void __free_winch(struct work_struct *work)
 610 {
 611         struct winch *winch = container_of(work, struct winch, work);
 612         um_free_irq(WINCH_IRQ, winch);
 613
 614         if (winch->pid != -1)
 615                 os_kill_process(winch->pid, 1);
 616         if (winch->stack != 0)
 617                 free_stack(winch->stack, 0);
 618         kfree(winch);
 619 }
 620
 621 static void free_winch(struct winch *winch)
 622 {
 623         int fd = winch->fd;
 624         winch->fd = -1;
 625         if (fd != -1)
 626                 os_close_file(fd);
 627         list_del(&winch->list);
 628         __free_winch(&winch->work);
 629 }
 630
 631 static irqreturn_t winch_interrupt(int irq, void *data)
 632 {
 633         struct winch *winch = data;
 634         struct tty_struct *tty;
 635         struct line *line;
 636         int fd = winch->fd;
 637         int err;
 638         char c;
 639
 640         if (fd != -1) {
 641                 err = generic_read(fd, &c, NULL);
 642                 if (err < 0) {
 643                         if (err != -EAGAIN) {
 644                                 winch->fd = -1;
 645                                 list_del(&winch->list);
 646                                 os_close_file(fd);
 647                                 printk(KERN_ERR "winch_interrupt : "
 648                                        "read failed, errno = %d\n", -err);
 649                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
 650                                        "support\n", winch->tty_fd);
 651                                 INIT_WORK(&winch->work, __free_winch);
 652                                 schedule_work(&winch->work);
 653                                 return IRQ_HANDLED;
 654                         }
 655                         goto out;
 656                 }
 657         }
 658         tty = winch->tty;
 659         if (tty != NULL) {
 660                 line = tty->driver_data;
 661                 if (line != NULL) {
 662                         chan_window_size(line, &tty->winsize.ws_row,
 663                                          &tty->winsize.ws_col);
 664                         kill_pgrp(tty->pgrp, SIGWINCH, 1);
 665                 }
 666         }
 667  out:
 668         if (winch->fd != -1)
 669                 reactivate_fd(winch->fd, WINCH_IRQ);
 670         return IRQ_HANDLED;
 671 }
 672
 673 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
 674                         unsigned long stack)
 675 {
 676         struct winch *winch;
 677
 678         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 679         if (winch == NULL) {
 680                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
 681                 goto cleanup;
 682         }
 683
 684         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 685                                    .fd          = fd,
 686                                    .tty_fd      = tty_fd,
 687                                    .pid         = pid,
 688                                    .tty         = tty,
 689                                    .stack       = stack });
 690
 691         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 692                            IRQF_SHARED, "winch", winch) < 0) {
 693                 printk(KERN_ERR "register_winch_irq - failed to register "
 694                        "IRQ\n");
 695                 goto out_free;
 696         }
 697
 698         spin_lock(&winch_handler_lock);
 699         list_add(&winch->list, &winch_handlers);
 700         spin_unlock(&winch_handler_lock);
 701
 702         return;
 703
 704  out_free:
 705         kfree(winch);
 706  cleanup:
 707         os_kill_process(pid, 1);
 708         os_close_file(fd);
 709         if (stack != 0)
 710                 free_stack(stack, 0);
 711 }
 712
 713 static void unregister_winch(struct tty_struct *tty)
 714 {
 715         struct list_head *ele, *next;
 716         struct winch *winch;
 717
 718         spin_lock(&winch_handler_lock);
 719
 720         list_for_each_safe(ele, next, &winch_handlers) {
 721                 winch = list_entry(ele, struct winch, list);
 722                 if (winch->tty == tty) {
 723                         free_winch(winch);
 724                         break;
 725                 }
 726         }
 727         spin_unlock(&winch_handler_lock);
 728 }
 729
 730 static void winch_cleanup(void)
 731 {
 732         struct list_head *ele, *next;
 733         struct winch *winch;
 734
 735         spin_lock(&winch_handler_lock);
 736
 737         list_for_each_safe(ele, next, &winch_handlers) {
 738                 winch = list_entry(ele, struct winch, list);
 739                 free_winch(winch);
 740         }
 741
 742         spin_unlock(&winch_handler_lock);
 743 }
 744 __uml_exitcall(winch_cleanup);
 745
 746 char *add_xterm_umid(char *base)
 747 {
 748         char *umid, *title;
 749         int len;
 750
 751         umid = get_umid();
 752         if (*umid == '\0')
 753                 return base;
 754
 755         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 756         title = kmalloc(len, GFP_KERNEL);
 757         if (title == NULL) {
 758                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
 759                 return base;
 760         }
 761
 762         snprintf(title, len, "%s (%s)", base, umid);
 763         return title;
 764 }