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, port);
 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 void unregister_winch(struct tty_struct *tty);
 319
 320 static void line_destruct(struct tty_port *port)
 321 {
 322         struct tty_struct *tty = tty_port_tty_get(port);
 323         struct line *line = tty->driver_data;
 324
 325         if (line->sigio) {
 326                 unregister_winch(tty);
 327                 line->sigio = 0;
 328         }
 329 }
 330
 331 static const struct tty_port_operations line_port_ops = {
 332         .activate = line_activate,
 333         .destruct = line_destruct,
 334 };
 335
 336 int line_open(struct tty_struct *tty, struct file *filp)
 337 {
 338         struct line *line = tty->driver_data;
 339
 340         return tty_port_open(&line->port, tty, filp);
 341 }
 342
 343 int line_install(struct tty_driver *driver, struct tty_struct *tty,
 344                  struct line *line)
 345 {
 346         int ret;
 347
 348         ret = tty_standard_install(driver, tty);
 349         if (ret)
 350                 return ret;
 351
 352         tty->driver_data = line;
 353
 354         return 0;
 355 }
 356
 357 void line_close(struct tty_struct *tty, struct file * filp)
 358 {
 359         struct line *line = tty->driver_data;
 360
 361         tty_port_close(&line->port, tty, filp);
 362 }
 363
 364 void line_hangup(struct tty_struct *tty)
 365 {
 366         struct line *line = tty->driver_data;
 367
 368         tty_port_hangup(&line->port);
 369 }
 370
 371 void close_lines(struct line *lines, int nlines)
 372 {
 373         int i;
 374
 375         for(i = 0; i < nlines; i++)
 376                 close_chan(&lines[i]);
 377 }
 378
 379 int setup_one_line(struct line *lines, int n, char *init,
 380                    const struct chan_opts *opts, char **error_out)
 381 {
 382         struct line *line = &lines[n];
 383         struct tty_driver *driver = line->driver->driver;
 384         int err = -EINVAL;
 385
 386         if (line->port.count) {
 387                 *error_out = "Device is already open";
 388                 goto out;
 389         }
 390
 391         if (!strcmp(init, "none")) {
 392                 if (line->valid) {
 393                         line->valid = 0;
 394                         kfree(line->init_str);
 395                         tty_unregister_device(driver, n);
 396                         parse_chan_pair(NULL, line, n, opts, error_out);
 397                         err = 0;
 398                 }
 399         } else {
 400                 char *new = kstrdup(init, GFP_KERNEL);
 401                 if (!new) {
 402                         *error_out = "Failed to allocate memory";
 403                         return -ENOMEM;
 404                 }
 405                 if (line->valid) {
 406                         tty_unregister_device(driver, n);
 407                         kfree(line->init_str);
 408                 }
 409                 line->init_str = new;
 410                 line->valid = 1;
 411                 err = parse_chan_pair(new, line, n, opts, error_out);
 412                 if (!err) {
 413                         struct device *d = tty_port_register_device(&line->port,
 414                                         driver, n, NULL);
 415                         if (IS_ERR(d)) {
 416                                 *error_out = "Failed to register device";
 417                                 err = PTR_ERR(d);
 418                                 parse_chan_pair(NULL, line, n, opts, error_out);
 419                         }
 420                 }
 421                 if (err) {
 422                         line->init_str = NULL;
 423                         line->valid = 0;
 424                         kfree(new);
 425                 }
 426         }
 427 out:
 428         return err;
 429 }
 430
 431 /*
 432  * Common setup code for both startup command line and mconsole initialization.
 433  * @lines contains the array (of size @num) to modify;
 434  * @init is the setup string;
 435  * @error_out is an error string in the case of failure;
 436  */
 437
 438 int line_setup(char **conf, unsigned int num, char **def,
 439                char *init, char *name)
 440 {
 441         char *error;
 442
 443         if (*init == '=') {
 444                 /*
 445                  * We said con=/ssl= instead of con#=, so we are configuring all
 446                  * consoles at once.
 447                  */
 448                 *def = init + 1;
 449         } else {
 450                 char *end;
 451                 unsigned n = simple_strtoul(init, &end, 0);
 452
 453                 if (*end != '=') {
 454                         error = "Couldn't parse device number";
 455                         goto out;
 456                 }
 457                 if (n >= num) {
 458                         error = "Device number out of range";
 459                         goto out;
 460                 }
 461                 conf[n] = end + 1;
 462         }
 463         return 0;
 464
 465 out:
 466         printk(KERN_ERR "Failed to set up %s with "
 467                "configuration string \"%s\" : %s\n", name, init, error);
 468         return -EINVAL;
 469 }
 470
 471 int line_config(struct line *lines, unsigned int num, char *str,
 472                 const struct chan_opts *opts, char **error_out)
 473 {
 474         char *end;
 475         int n;
 476
 477         if (*str == '=') {
 478                 *error_out = "Can't configure all devices from mconsole";
 479                 return -EINVAL;
 480         }
 481
 482         n = simple_strtoul(str, &end, 0);
 483         if (*end++ != '=') {
 484                 *error_out = "Couldn't parse device number";
 485                 return -EINVAL;
 486         }
 487         if (n >= num) {
 488                 *error_out = "Device number out of range";
 489                 return -EINVAL;
 490         }
 491
 492         return setup_one_line(lines, n, end, opts, error_out);
 493 }
 494
 495 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 496                     int size, char **error_out)
 497 {
 498         struct line *line;
 499         char *end;
 500         int dev, n = 0;
 501
 502         dev = simple_strtoul(name, &end, 0);
 503         if ((*end != '\0') || (end == name)) {
 504                 *error_out = "line_get_config failed to parse device number";
 505                 return 0;
 506         }
 507
 508         if ((dev < 0) || (dev >= num)) {
 509                 *error_out = "device number out of range";
 510                 return 0;
 511         }
 512
 513         line = &lines[dev];
 514
 515         if (!line->valid)
 516                 CONFIG_CHUNK(str, size, n, "none", 1);
 517         else {
 518                 struct tty_struct *tty = tty_port_tty_get(&line->port);
 519                 if (tty == NULL) {
 520                         CONFIG_CHUNK(str, size, n, line->init_str, 1);
 521                 } else {
 522                         n = chan_config_string(line, str, size, error_out);
 523                         tty_kref_put(tty);
 524                 }
 525         }
 526
 527         return n;
 528 }
 529
 530 int line_id(char **str, int *start_out, int *end_out)
 531 {
 532         char *end;
 533         int n;
 534
 535         n = simple_strtoul(*str, &end, 0);
 536         if ((*end != '\0') || (end == *str))
 537                 return -1;
 538
 539         *str = end;
 540         *start_out = n;
 541         *end_out = n;
 542         return n;
 543 }
 544
 545 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 546 {
 547         if (n >= num) {
 548                 *error_out = "Device number out of range";
 549                 return -EINVAL;
 550         }
 551         return setup_one_line(lines, n, "none", NULL, error_out);
 552 }
 553
 554 int register_lines(struct line_driver *line_driver,
 555                    const struct tty_operations *ops,
 556                    struct line *lines, int nlines)
 557 {
 558         struct tty_driver *driver = alloc_tty_driver(nlines);
 559         int err;
 560         int i;
 561
 562         if (!driver)
 563                 return -ENOMEM;
 564
 565         driver->driver_name = line_driver->name;
 566         driver->name = line_driver->device_name;
 567         driver->major = line_driver->major;
 568         driver->minor_start = line_driver->minor_start;
 569         driver->type = line_driver->type;
 570         driver->subtype = line_driver->subtype;
 571         driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 572         driver->init_termios = tty_std_termios;
 573
 574         for (i = 0; i < nlines; i++) {
 575                 tty_port_init(&lines[i].port);
 576                 lines[i].port.ops = &line_port_ops;
 577                 spin_lock_init(&lines[i].lock);
 578                 lines[i].driver = line_driver;
 579                 INIT_LIST_HEAD(&lines[i].chan_list);
 580         }
 581         tty_set_operations(driver, ops);
 582
 583         err = tty_register_driver(driver);
 584         if (err) {
 585                 printk(KERN_ERR "register_lines : can't register %s driver\n",
 586                        line_driver->name);
 587                 put_tty_driver(driver);
 588                 for (i = 0; i < nlines; i++)
 589                         tty_port_destroy(&lines[i].port);
 590                 return err;
 591         }
 592
 593         line_driver->driver = driver;
 594         mconsole_register_dev(&line_driver->mc);
 595         return 0;
 596 }
 597
 598 static DEFINE_SPINLOCK(winch_handler_lock);
 599 static LIST_HEAD(winch_handlers);
 600
 601 struct winch {
 602         struct list_head list;
 603         int fd;
 604         int tty_fd;
 605         int pid;
 606         struct tty_port *port;
 607         unsigned long stack;
 608         struct work_struct work;
 609 };
 610
 611 static void __free_winch(struct work_struct *work)
 612 {
 613         struct winch *winch = container_of(work, struct winch, work);
 614         um_free_irq(WINCH_IRQ, winch);
 615
 616         if (winch->pid != -1)
 617                 os_kill_process(winch->pid, 1);
 618         if (winch->stack != 0)
 619                 free_stack(winch->stack, 0);
 620         kfree(winch);
 621 }
 622
 623 static void free_winch(struct winch *winch)
 624 {
 625         int fd = winch->fd;
 626         winch->fd = -1;
 627         if (fd != -1)
 628                 os_close_file(fd);
 629         list_del(&winch->list);
 630         __free_winch(&winch->work);
 631 }
 632
 633 static irqreturn_t winch_interrupt(int irq, void *data)
 634 {
 635         struct winch *winch = data;
 636         struct tty_struct *tty;
 637         struct line *line;
 638         int fd = winch->fd;
 639         int err;
 640         char c;
 641
 642         if (fd != -1) {
 643                 err = generic_read(fd, &c, NULL);
 644                 if (err < 0) {
 645                         if (err != -EAGAIN) {
 646                                 winch->fd = -1;
 647                                 list_del(&winch->list);
 648                                 os_close_file(fd);
 649                                 printk(KERN_ERR "winch_interrupt : "
 650                                        "read failed, errno = %d\n", -err);
 651                                 printk(KERN_ERR "fd %d is losing SIGWINCH "
 652                                        "support\n", winch->tty_fd);
 653                                 INIT_WORK(&winch->work, __free_winch);
 654                                 schedule_work(&winch->work);
 655                                 return IRQ_HANDLED;
 656                         }
 657                         goto out;
 658                 }
 659         }
 660         tty = tty_port_tty_get(winch->port);
 661         if (tty != NULL) {
 662                 line = tty->driver_data;
 663                 if (line != NULL) {
 664                         chan_window_size(line, &tty->winsize.ws_row,
 665                                          &tty->winsize.ws_col);
 666                         kill_pgrp(tty->pgrp, SIGWINCH, 1);
 667                 }
 668                 tty_kref_put(tty);
 669         }
 670  out:
 671         if (winch->fd != -1)
 672                 reactivate_fd(winch->fd, WINCH_IRQ);
 673         return IRQ_HANDLED;
 674 }
 675
 676 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_port *port,
 677                         unsigned long stack)
 678 {
 679         struct winch *winch;
 680
 681         winch = kmalloc(sizeof(*winch), GFP_KERNEL);
 682         if (winch == NULL) {
 683                 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
 684                 goto cleanup;
 685         }
 686
 687         *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
 688                                    .fd          = fd,
 689                                    .tty_fd      = tty_fd,
 690                                    .pid         = pid,
 691                                    .port        = port,
 692                                    .stack       = stack });
 693
 694         if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
 695                            IRQF_SHARED, "winch", winch) < 0) {
 696                 printk(KERN_ERR "register_winch_irq - failed to register "
 697                        "IRQ\n");
 698                 goto out_free;
 699         }
 700
 701         spin_lock(&winch_handler_lock);
 702         list_add(&winch->list, &winch_handlers);
 703         spin_unlock(&winch_handler_lock);
 704
 705         return;
 706
 707  out_free:
 708         kfree(winch);
 709  cleanup:
 710         os_kill_process(pid, 1);
 711         os_close_file(fd);
 712         if (stack != 0)
 713                 free_stack(stack, 0);
 714 }
 715
 716 static void unregister_winch(struct tty_struct *tty)
 717 {
 718         struct list_head *ele, *next;
 719         struct winch *winch;
 720         struct tty_struct *wtty;
 721
 722         spin_lock(&winch_handler_lock);
 723
 724         list_for_each_safe(ele, next, &winch_handlers) {
 725                 winch = list_entry(ele, struct winch, list);
 726                 wtty = tty_port_tty_get(winch->port);
 727                 if (wtty == tty) {
 728                         free_winch(winch);
 729                         break;
 730                 }
 731                 tty_kref_put(wtty);
 732         }
 733         spin_unlock(&winch_handler_lock);
 734 }
 735
 736 static void winch_cleanup(void)
 737 {
 738         struct list_head *ele, *next;
 739         struct winch *winch;
 740
 741         spin_lock(&winch_handler_lock);
 742
 743         list_for_each_safe(ele, next, &winch_handlers) {
 744                 winch = list_entry(ele, struct winch, list);
 745                 free_winch(winch);
 746         }
 747
 748         spin_unlock(&winch_handler_lock);
 749 }
 750 __uml_exitcall(winch_cleanup);
 751
 752 char *add_xterm_umid(char *base)
 753 {
 754         char *umid, *title;
 755         int len;
 756
 757         umid = get_umid();
 758         if (*umid == '\0')
 759                 return base;
 760
 761         len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
 762         title = kmalloc(len, GFP_KERNEL);
 763         if (title == NULL) {
 764                 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
 765                 return base;
 766         }
 767
 768         snprintf(title, len, "%s (%s)", base, umid);
 769         return title;
 770 }