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/signal.h>
   9 #include <linux/slab.h>
  10
  11 #include "chan.h"
  12 #include <irq_kern.h>
  13 #include <irq_user.h>
  14 #include <kern_util.h>
  15 #include <os.h>
  16
  17 #define LINE_BUFSIZE 4096
  18
  19 static irqreturn_t line_interrupt(int irq, void *data)
  20 {
  21         struct chan *chan = data;
  22         struct line *line = chan->line;
  23
  24         if (line)
  25                 chan_interrupt(line, irq);
  26
  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, 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         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) && (err != -EAGAIN)) {
 265                 line->head = line->buffer;
 266                 line->tail = line->buffer;
 267         }
 268         spin_unlock(&line->lock);
 269
 270         tty_port_tty_wakeup(&line->port);
 271
 272         return IRQ_HANDLED;
 273 }
 274
 275 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 276 {
 277         const struct line_driver *driver = line->driver;
 278         int err = 0;
 279
 280         if (input)
 281                 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
 282                                      line_interrupt, IRQF_SHARED,
 283                                      driver->read_irq_name, data);
 284         if (err)
 285                 return err;
 286         if (output)
 287                 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
 288                                      line_write_interrupt, IRQF_SHARED,
 289                                      driver->write_irq_name, data);
 290         return err;
 291 }
 292
 293 static int line_activate(struct tty_port *port, struct tty_struct *tty)
 294 {
 295         int ret;
 296         struct line *line = tty->driver_data;
 297
 298         ret = enable_chan(line);
 299         if (ret)
 300                 return ret;
 301
 302         if (!line->sigio) {
 303                 chan_enable_winch(line->chan_out, port);
 304                 line->sigio = 1;
 305         }
 306
 307         chan_window_size(line, &tty->winsize.ws_row,
 308                 &tty->winsize.ws_col);
 309
 310         return 0;
 311 }
 312
 313 static void unregister_winch(struct tty_struct *tty);
 314
 315 static void line_destruct(struct tty_port *port)
 316 {
 317         struct tty_struct *tty = tty_port_tty_get(port);
 318         struct line *line = tty->driver_data;
 319
 320         if (line->sigio) {
 321                 unregister_winch(tty);
 322                 line->sigio = 0;
 323         }
 324 }
 325
 326 static const struct tty_port_operations line_port_ops = {
 327         .activate = line_activate,
 328         .destruct = line_destruct,
 329 };
 330
 331 int line_open(struct tty_struct *tty, struct file *filp)
 332 {
 333         struct line *line = tty->driver_data;
 334
 335         return tty_port_open(&line->port, tty, filp);
 336 }
 337
 338 int line_install(struct tty_driver *driver, struct tty_struct *tty,
 339                  struct line *line)
 340 {
 341         int ret;
 342
 343         ret = tty_standard_install(driver, tty);
 344         if (ret)
 345                 return ret;
 346
 347         tty->driver_data = line;
 348
 349         return 0;
 350 }
 351
 352 void line_close(struct tty_struct *tty, struct file * filp)
 353 {
 354         struct line *line = tty->driver_data;
 355
 356         tty_port_close(&line->port, tty, filp);
 357 }
 358
 359 void line_hangup(struct tty_struct *tty)
 360 {
 361         struct line *line = tty->driver_data;
 362
 363         tty_port_hangup(&line->port);
 364 }
 365
 366 void close_lines(struct line *lines, int nlines)
 367 {
 368         int i;
 369
 370         for(i = 0; i < nlines; i++)
 371                 close_chan(&lines[i]);
 372 }
 373
 374 int setup_one_line(struct line *lines, int n, char *init,
 375                    const struct chan_opts *opts, char **error_out)
 376 {
 377         struct line *line = &lines[n];
 378         struct tty_driver *driver = line->driver->driver;
 379         int err = -EINVAL;
 380
 381         if (line->port.count) {
 382                 *error_out = "Device is already open";
 383                 goto out;
 384         }
 385
 386         if (!strcmp(init, "none")) {
 387                 if (line->valid) {
 388                         line->valid = 0;
 389                         kfree(line->init_str);
 390                         tty_unregister_device(driver, n);
 391                         parse_chan_pair(NULL, line, n, opts, error_out);
 392                         err = 0;
 393                 }
 394         } else {
 395                 char *new = kstrdup(init, GFP_KERNEL);
 396                 if (!new) {
 397                         *error_out = "Failed to allocate memory";
 398                         return -ENOMEM;
 399                 }
 400                 if (line->valid) {
 401                         tty_unregister_device(driver, n);
 402                         kfree(line->init_str);
 403                 }
 404                 line->init_str = new;
 405                 line->valid = 1;
 406                 err = parse_chan_pair(new, line, n, opts, error_out);
 407                 if (!err) {
 408                         struct device *d = tty_port_register_device(&line->port,
 409                                         driver, n, NULL);
 410                         if (IS_ERR(d)) {
 411                                 *error_out = "Failed to register device";
 412                                 err = PTR_ERR(d);
 413                                 parse_chan_pair(NULL, line, n, opts, error_out);
 414                         }
 415                 }
 416                 if (err) {
 417                         line->init_str = NULL;
 418                         line->valid = 0;
 419                         kfree(new);
 420                 }
 421         }
 422 out:
 423         return err;
 424 }
 425
 426 /*
 427  * Common setup code for both startup command line and mconsole initialization.
 428  * @lines contains the array (of size @num) to modify;
 429  * @init is the setup string;
 430  * @error_out is an error string in the case of failure;
 431  */
 432
 433 int line_setup(char **conf, unsigned int num, char **def,
 434                char *init, char *name)
 435 {
 436         char *error;
 437
 438         if (*init == '=') {
 439                 /*
 440                  * We said con=/ssl= instead of con#=, so we are configuring all
 441                  * consoles at once.
 442                  */
 443                 *def = init + 1;
 444         } else {
 445                 char *end;
 446                 unsigned n = simple_strtoul(init, &end, 0);
 447
 448                 if (*end != '=') {
 449                         error = "Couldn't parse device number";
 450                         goto out;
 451                 }
 452                 if (n >= num) {
 453                         error = "Device number out of range";
 454                         goto out;
 455                 }
 456                 conf[n] = end + 1;
 457         }
 458         return 0;
 459
 460 out:
 461         printk(KERN_ERR "Failed to set up %s with "
 462                "configuration string \"%s\" : %s\n", name, init, error);
 463         return -EINVAL;
 464 }
 465
 466 int line_config(struct line *lines, unsigned int num, char *str,
 467                 const struct chan_opts *opts, char **error_out)
 468 {
 469         char *end;
 470         int n;
 471
 472         if (*str == '=') {
 473                 *error_out = "Can't configure all devices from mconsole";
 474                 return -EINVAL;
 475         }
 476
 477         n = simple_strtoul(str, &end, 0);
 478         if (*end++ != '=') {
 479                 *error_out = "Couldn't parse device number";
 480                 return -EINVAL;
 481         }
 482         if (n >= num) {
 483                 *error_out = "Device number out of range";
 484                 return -EINVAL;
 485         }
 486
 487         return setup_one_line(lines, n, end, opts, error_out);
 488 }
 489
 490 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 491                     int size, char **error_out)
 492 {
 493         struct line *line;
 494         char *end;
 495         int dev, n = 0;
 496
 497         dev = simple_strtoul(name, &end, 0);
 498         if ((*end != '\0') || (end == name)) {
 499                 *error_out = "line_get_config failed to parse device number";
 500                 return 0;
 501         }
 502
 503         if ((dev < 0) || (dev >= num)) {
 504                 *error_out = "device number out of range";
 505                 return 0;
 506         }
 507
 508         line = &lines[dev];
 509
 510         if (!line->valid)
 511                 CONFIG_CHUNK(str, size, n, "none", 1);
 512         else {
 513                 struct tty_struct *tty = tty_port_tty_get(&line->port);
 514                 if (tty == NULL) {
 515                         CONFIG_CHUNK(str, size, n, line->init_str, 1);
 516                 } else {
 517                         n = chan_config_string(line, str, size, error_out);
 518                         tty_kref_put(tty);
 519                 }
 520         }
 521
 522         return n;
 523 }
 524
 525 int line_id(char **str, int *start_out, int *end_out)
 526 {
 527         char *end;
 528         int n;
 529
 530         n = simple_strtoul(*str, &end, 0);
 531         if ((*end != '\0') || (end == *str))
 532                 return -1;
 533
 534         *str = end;
 535         *start_out = n;
 536         *end_out = n;
 537         return n;
 538 }
 539
 540 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 541 {
 542         if (n >= num) {
 543                 *error_out = "Device number out of range";
 544                 return -EINVAL;
 545         }
 546         return setup_one_line(lines, n, "none", NULL, error_out);
 547 }
 548
 549 int register_lines(struct line_driver *line_driver,
 550                    const struct tty_operations *ops,
 551                    struct line *lines, int nlines)
 552 {
 553         struct tty_driver *driver = alloc_tty_driver(nlines);
 554         int err;
 555         int i;
 556
 557         if (!driver)
 558                 return -ENOMEM;
 559
 560         driver->driver_name = line_driver->name;
 561         driver->name = line_driver->device_name;
 562         driver->major = line_driver->major;
 563         driver->minor_start = line_driver->minor_start;
 564         driver->type = line_driver->type;
 565         driver->subtype = line_driver->subtype;
 566         driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 567         driver->init_termios = tty_std_termios;
 568
 569         for (i = 0; i < nlines; i++) {
 570                 tty_port_init(&lines[i].port);
 571                 lines[i].port.ops = &line_port_ops;
 572                 spin_lock_init(&lines[i].lock);
 573                 lines[i].driver = line_driver;
 574                 INIT_LIST_HEAD(&lines[i].chan_list);
 575         }
 576         tty_set_operations(driver, ops);
 577
 578         err = tty_register_driver(driver);
 579         if (err) {
 580                 printk(KERN_ERR "register_lines : can't register %s driver\n",
 581                        line_driver->name);
 582                 put_tty_driver(driver);
 583                 for (i = 0; i < nlines; i++)
 584                         tty_port_destroy(&lines[i].port);
 585                 return err;
 586         }
 587
 588         line_driver->driver = driver;
 589         mconsole_register_dev(&line_driver->mc);
 590         return 0;
 591 }
 592
 593 static DEFINE_SPINLOCK(winch_handler_lock);
 594 static LIST_HEAD(winch_handlers);
 595
 596 struct winch {
 597         struct list_head list;
 598         int fd;
 599         int tty_fd;
 600         int pid;
 601         struct tty_port *port;
 602         unsigned long stack;
 603         struct work_struct work;
 604 };
 605
 606 static void __free_winch(struct work_struct *work)
 607 {
 608         struct winch *winch = container_of(work, struct winch, work);
 609         um_free_irq(WINCH_IRQ, winch);
 610
 611         if (winch->pid != -1)
 612                 os_kill_process(winch->pid, 1);
 613         if (winch->stack != 0)
 614                 free_stack(winch->stack, 0);
 615         kfree(winch);
 616 }
 617
 618 static void free_winch(struct winch *winch)
 619 {
 620         int fd = winch->fd;
 621         winch->fd = -1;
 622         if (fd != -1)
 623                 os_close_file(fd);
 624         list_del(&winch->list);
 625         __free_winch(&winch->work);
 626 }
 627
 628 static irqreturn_t winch_interrupt(int irq, void *data)
 629 {
 630         struct winch *winch = data;
 631         struct tty_struct *tty;
 632         struct line *line;
 633         int fd = winch->fd;
 634         int err;
 635         char c;
 636         struct pid *pgrp;
 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 = tty_port_tty_get(winch->port);
 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                         pgrp = tty_get_pgrp(tty);
 663                         if (pgrp)
 664                                 kill_pgrp(pgrp, SIGWINCH, 1);
 665                         put_pid(pgrp);
 666                 }
 667                 tty_kref_put(tty);
 668         }
 669  out:
 670         if (winch->fd != -1)
 671                 reactivate_fd(winch->fd, WINCH_IRQ);
 672         return IRQ_HANDLED;
 673 }
 674
 675 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_port *port,
 676                         unsigned long stack)
 677 {
 678         struct winch *winch;
 679
 680         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 681         if (winch == NULL) {
 682                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
 683                 goto cleanup;
 684         }
 685
 686         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 687                                    .fd          = fd,
 688                                    .tty_fd      = tty_fd,
 689                                    .pid         = pid,
 690                                    .port        = port,
 691                                    .stack       = stack });
 692
 693         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 694                            IRQF_SHARED, "winch", winch) < 0) {
 695                 printk(KERN_ERR "register_winch_irq - failed to register "
 696                        "IRQ\n");
 697                 goto out_free;
 698         }
 699
 700         spin_lock(&winch_handler_lock);
 701         list_add(&winch->list, &winch_handlers);
 702         spin_unlock(&winch_handler_lock);
 703
 704         return;
 705
 706  out_free:
 707         kfree(winch);
 708  cleanup:
 709         os_kill_process(pid, 1);
 710         os_close_file(fd);
 711         if (stack != 0)
 712                 free_stack(stack, 0);
 713 }
 714
 715 static void unregister_winch(struct tty_struct *tty)
 716 {
 717         struct list_head *ele, *next;
 718         struct winch *winch;
 719         struct tty_struct *wtty;
 720
 721         spin_lock(&winch_handler_lock);
 722
 723         list_for_each_safe(ele, next, &winch_handlers) {
 724                 winch = list_entry(ele, struct winch, list);
 725                 wtty = tty_port_tty_get(winch->port);
 726                 if (wtty == tty) {
 727                         free_winch(winch);
 728                         break;
 729                 }
 730                 tty_kref_put(wtty);
 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 }