1 /*- 2 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Portions of this software were developed under sponsorship from Snow 6 * B.V., the Netherlands. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include "opt_tty.h" 34 35 /* Add compatibility bits for FreeBSD. */ 36 #define PTS_COMPAT 37 #ifdef DEV_PTY 38 /* Add /dev/ptyXX compat bits. */ 39 #define PTS_EXTERNAL 40 #endif /* DEV_PTY */ 41 /* Add bits to make Linux binaries work. */ 42 #define PTS_LINUX 43 44 #include <sys/param.h> 45 #include <sys/lock.h> 46 #include <sys/condvar.h> 47 #include <sys/conf.h> 48 #include <sys/fcntl.h> 49 #include <sys/file.h> 50 #include <sys/filedesc.h> 51 #include <sys/filio.h> 52 #include <sys/kernel.h> 53 #include <sys/malloc.h> 54 #include <sys/poll.h> 55 #include <sys/proc.h> 56 #include <sys/resourcevar.h> 57 #include <sys/serial.h> 58 #include <sys/stat.h> 59 #include <sys/syscall.h> 60 #include <sys/syscallsubr.h> 61 #include <sys/sysent.h> 62 #include <sys/sysproto.h> 63 #include <sys/systm.h> 64 #include <sys/tty.h> 65 #include <sys/ttycom.h> 66 67 #include <machine/stdarg.h> 68 69 static struct unrhdr *pts_pool; 70 #define MAXPTSDEVS 999 71 72 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device"); 73 74 /* 75 * Per-PTS structure. 76 * 77 * List of locks 78 * (t) locked by tty_lock() 79 * (c) const until freeing 80 */ 81 struct pts_softc { 82 int pts_unit; /* (c) Device unit number. */ 83 unsigned int pts_flags; /* (t) Device flags. */ 84 #define PTS_PKT 0x1 /* Packet mode. */ 85 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */ 86 char pts_pkt; /* (t) Unread packet mode data. */ 87 88 struct cv pts_inwait; /* (t) Blocking write() on master. */ 89 struct selinfo pts_inpoll; /* (t) Select queue for write(). */ 90 struct cv pts_outwait; /* (t) Blocking read() on master. */ 91 struct selinfo pts_outpoll; /* (t) Select queue for read(). */ 92 93 #ifdef PTS_EXTERNAL 94 struct cdev *pts_cdev; /* (c) Master device node. */ 95 #endif /* PTS_EXTERNAL */ 96 97 struct uidinfo *pts_uidinfo; /* (c) Resource limit. */ 98 }; 99 100 /* 101 * Controller-side file operations. 102 */ 103 104 static int 105 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 106 int flags, struct thread *td) 107 { 108 struct tty *tp = fp->f_data; 109 struct pts_softc *psc = tty_softc(tp); 110 int error = 0; 111 char pkt; 112 113 if (uio->uio_resid == 0) 114 return (0); 115 116 tty_lock(tp); 117 118 for (;;) { 119 /* 120 * Implement packet mode. When packet mode is turned on, 121 * the first byte contains a bitmask of events that 122 * occured (start, stop, flush, window size, etc). 123 */ 124 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) { 125 pkt = psc->pts_pkt; 126 psc->pts_pkt = 0; 127 tty_unlock(tp); 128 129 error = ureadc(pkt, uio); 130 return (error); 131 } 132 133 /* 134 * Transmit regular data. 135 * 136 * XXX: We shouldn't use ttydisc_getc_poll()! Even 137 * though in this implementation, there is likely going 138 * to be data, we should just call ttydisc_getc_uio() 139 * and use its return value to sleep. 140 */ 141 if (ttydisc_getc_poll(tp)) { 142 if (psc->pts_flags & PTS_PKT) { 143 /* 144 * XXX: Small race. Fortunately PTY 145 * consumers aren't multithreaded. 146 */ 147 148 tty_unlock(tp); 149 error = ureadc(TIOCPKT_DATA, uio); 150 if (error) 151 return (error); 152 tty_lock(tp); 153 } 154 155 error = ttydisc_getc_uio(tp, uio); 156 break; 157 } 158 159 /* Maybe the device isn't used anyway. */ 160 if (psc->pts_flags & PTS_FINISHED) 161 break; 162 163 /* Wait for more data. */ 164 if (fp->f_flag & O_NONBLOCK) { 165 error = EWOULDBLOCK; 166 break; 167 } 168 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx); 169 if (error != 0) 170 break; 171 } 172 173 tty_unlock(tp); 174 175 return (error); 176 } 177 178 static int 179 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 180 int flags, struct thread *td) 181 { 182 struct tty *tp = fp->f_data; 183 struct pts_softc *psc = tty_softc(tp); 184 char ib[256], *ibstart; 185 size_t iblen, rintlen; 186 int error = 0; 187 188 if (uio->uio_resid == 0) 189 return (0); 190 191 for (;;) { 192 ibstart = ib; 193 iblen = MIN(uio->uio_resid, sizeof ib); 194 error = uiomove(ib, iblen, uio); 195 196 tty_lock(tp); 197 if (error != 0) 198 goto done; 199 200 /* 201 * When possible, avoid the slow path. rint_bypass() 202 * copies all input to the input queue at once. 203 */ 204 MPASS(iblen > 0); 205 do { 206 if (ttydisc_can_bypass(tp)) { 207 /* Store data at once. */ 208 rintlen = ttydisc_rint_bypass(tp, 209 ibstart, iblen); 210 ibstart += rintlen; 211 iblen -= rintlen; 212 213 if (iblen == 0) { 214 /* All data written. */ 215 break; 216 } 217 } else { 218 error = ttydisc_rint(tp, *ibstart, 0); 219 if (error == 0) { 220 /* Character stored successfully. */ 221 ibstart++; 222 iblen--; 223 continue; 224 } 225 } 226 227 /* Maybe the device isn't used anyway. */ 228 if (psc->pts_flags & PTS_FINISHED) { 229 error = EIO; 230 goto done; 231 } 232 233 /* Wait for more data. */ 234 if (fp->f_flag & O_NONBLOCK) { 235 error = EWOULDBLOCK; 236 goto done; 237 } 238 239 /* Wake up users on the slave side. */ 240 ttydisc_rint_done(tp); 241 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx); 242 if (error != 0) 243 goto done; 244 } while (iblen > 0); 245 246 if (uio->uio_resid == 0) 247 break; 248 tty_unlock(tp); 249 } 250 251 done: ttydisc_rint_done(tp); 252 tty_unlock(tp); 253 return (error); 254 } 255 256 static int 257 ptsdev_ioctl(struct file *fp, u_long cmd, void *data, 258 struct ucred *active_cred, struct thread *td) 259 { 260 struct tty *tp = fp->f_data; 261 struct pts_softc *psc = tty_softc(tp); 262 int error = 0, sig; 263 264 switch (cmd) { 265 case FIONBIO: 266 /* This device supports non-blocking operation. */ 267 return (0); 268 case FIODGNAME: { 269 struct fiodgname_arg *fgn; 270 const char *p; 271 int i; 272 273 /* Reverse device name lookups, for ptsname() and ttyname(). */ 274 fgn = data; 275 #ifdef PTS_EXTERNAL 276 if (psc->pts_cdev != NULL) 277 p = devtoname(psc->pts_cdev); 278 else 279 #endif /* PTS_EXTERNAL */ 280 p = tty_devname(tp); 281 i = strlen(p) + 1; 282 if (i > fgn->len) 283 return (EINVAL); 284 return copyout(p, fgn->buf, i); 285 } 286 287 /* 288 * We need to implement TIOCGPGRP and TIOCGSID here again. When 289 * called on the pseudo-terminal master, it should not check if 290 * the terminal is the foreground terminal of the calling 291 * process. 292 * 293 * TIOCGETA is also implemented here. Various Linux PTY routines 294 * often call isatty(), which is implemented by tcgetattr(). 295 */ 296 #ifdef PTS_LINUX 297 case TIOCGETA: 298 /* Obtain terminal flags through tcgetattr(). */ 299 tty_lock(tp); 300 bcopy(&tp->t_termios, data, sizeof(struct termios)); 301 tty_unlock(tp); 302 return (0); 303 #endif /* PTS_LINUX */ 304 case TIOCSETAF: 305 case TIOCSETAW: 306 /* 307 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and 308 * TCSADRAIN into something different. If an application would 309 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may 310 * deadlock waiting for all data to be read. 311 */ 312 cmd = TIOCSETA; 313 break; 314 #if defined(PTS_COMPAT) || defined(PTS_LINUX) 315 case TIOCGPTN: 316 /* 317 * Get the device unit number. 318 */ 319 if (psc->pts_unit < 0) 320 return (ENOTTY); 321 *(unsigned int *)data = psc->pts_unit; 322 return (0); 323 #endif /* PTS_COMPAT || PTS_LINUX */ 324 case TIOCGPGRP: 325 /* Get the foreground process group ID. */ 326 tty_lock(tp); 327 if (tp->t_pgrp != NULL) 328 *(int *)data = tp->t_pgrp->pg_id; 329 else 330 *(int *)data = NO_PID; 331 tty_unlock(tp); 332 return (0); 333 case TIOCGSID: 334 /* Get the session leader process ID. */ 335 tty_lock(tp); 336 if (tp->t_session == NULL) 337 error = ENOTTY; 338 else 339 *(int *)data = tp->t_session->s_sid; 340 tty_unlock(tp); 341 return (error); 342 case TIOCPTMASTER: 343 /* Yes, we are a pseudo-terminal master. */ 344 return (0); 345 case TIOCSIG: 346 /* Signal the foreground process group. */ 347 sig = *(int *)data; 348 if (sig < 1 || sig >= NSIG) 349 return (EINVAL); 350 351 tty_lock(tp); 352 tty_signal_pgrp(tp, sig); 353 tty_unlock(tp); 354 return (0); 355 case TIOCPKT: 356 /* Enable/disable packet mode. */ 357 tty_lock(tp); 358 if (*(int *)data) 359 psc->pts_flags |= PTS_PKT; 360 else 361 psc->pts_flags &= ~PTS_PKT; 362 tty_unlock(tp); 363 return (0); 364 } 365 366 /* Just redirect this ioctl to the slave device. */ 367 tty_lock(tp); 368 error = tty_ioctl(tp, cmd, data, td); 369 tty_unlock(tp); 370 371 return (error); 372 } 373 374 static int 375 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred, 376 struct thread *td) 377 { 378 struct tty *tp = fp->f_data; 379 struct pts_softc *psc = tty_softc(tp); 380 int revents = 0; 381 382 tty_lock(tp); 383 384 if (psc->pts_flags & PTS_FINISHED) { 385 /* Slave device is not opened. */ 386 tty_unlock(tp); 387 return (events & 388 (POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM)); 389 } 390 391 if (events & (POLLIN|POLLRDNORM)) { 392 /* See if we can getc something. */ 393 if (ttydisc_getc_poll(tp) || 394 (psc->pts_flags & PTS_PKT && psc->pts_pkt)) 395 revents |= events & (POLLIN|POLLRDNORM); 396 } 397 if (events & (POLLOUT|POLLWRNORM)) { 398 /* See if we can rint something. */ 399 if (ttydisc_rint_poll(tp)) 400 revents |= events & (POLLOUT|POLLWRNORM); 401 } 402 403 /* 404 * No need to check for POLLHUP here. This device cannot be used 405 * as a callout device, which means we always have a carrier, 406 * because the master is. 407 */ 408 409 if (revents == 0) { 410 /* 411 * This code might look misleading, but the naming of 412 * poll events on this side is the opposite of the slave 413 * device. 414 */ 415 if (events & (POLLIN|POLLRDNORM)) 416 selrecord(td, &psc->pts_outpoll); 417 if (events & (POLLOUT|POLLWRNORM)) 418 selrecord(td, &psc->pts_inpoll); 419 } 420 421 tty_unlock(tp); 422 423 return (revents); 424 } 425 426 static int 427 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 428 struct thread *td) 429 { 430 struct tty *tp = fp->f_data; 431 #ifdef PTS_EXTERNAL 432 struct pts_softc *psc = tty_softc(tp); 433 #endif /* PTS_EXTERNAL */ 434 struct cdev *dev = tp->t_dev; 435 436 /* 437 * According to POSIX, we must implement an fstat(). This also 438 * makes this implementation compatible with Linux binaries, 439 * because Linux calls fstat() on the pseudo-terminal master to 440 * obtain st_rdev. 441 * 442 * XXX: POSIX also mentions we must fill in st_dev, but how? 443 */ 444 445 bzero(sb, sizeof *sb); 446 #ifdef PTS_EXTERNAL 447 if (psc->pts_cdev != NULL) 448 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev); 449 else 450 #endif /* PTS_EXTERNAL */ 451 sb->st_ino = sb->st_rdev = tty_udev(tp); 452 453 sb->st_atimespec = dev->si_atime; 454 sb->st_ctimespec = dev->si_ctime; 455 sb->st_mtimespec = dev->si_mtime; 456 sb->st_uid = dev->si_uid; 457 sb->st_gid = dev->si_gid; 458 sb->st_mode = dev->si_mode | S_IFCHR; 459 460 return (0); 461 } 462 463 static int 464 ptsdev_close(struct file *fp, struct thread *td) 465 { 466 struct tty *tp = fp->f_data; 467 468 /* Deallocate TTY device. */ 469 tty_lock(tp); 470 tty_rel_gone(tp); 471 472 return (0); 473 } 474 475 static struct fileops ptsdev_ops = { 476 .fo_read = ptsdev_read, 477 .fo_write = ptsdev_write, 478 .fo_ioctl = ptsdev_ioctl, 479 .fo_poll = ptsdev_poll, 480 .fo_stat = ptsdev_stat, 481 .fo_close = ptsdev_close, 482 .fo_flags = DFLAG_PASSABLE, 483 }; 484 485 /* 486 * Driver-side hooks. 487 */ 488 489 static void 490 ptsdrv_outwakeup(struct tty *tp) 491 { 492 struct pts_softc *psc = tty_softc(tp); 493 494 cv_broadcast(&psc->pts_outwait); 495 selwakeup(&psc->pts_outpoll); 496 } 497 498 static void 499 ptsdrv_inwakeup(struct tty *tp) 500 { 501 struct pts_softc *psc = tty_softc(tp); 502 503 cv_broadcast(&psc->pts_inwait); 504 selwakeup(&psc->pts_inpoll); 505 } 506 507 static int 508 ptsdrv_open(struct tty *tp) 509 { 510 struct pts_softc *psc = tty_softc(tp); 511 512 psc->pts_flags &= ~PTS_FINISHED; 513 514 return (0); 515 } 516 517 static void 518 ptsdrv_close(struct tty *tp) 519 { 520 struct pts_softc *psc = tty_softc(tp); 521 522 /* Wake up any blocked readers/writers. */ 523 ptsdrv_outwakeup(tp); 524 ptsdrv_inwakeup(tp); 525 526 psc->pts_flags |= PTS_FINISHED; 527 } 528 529 static void 530 ptsdrv_pktnotify(struct tty *tp, char event) 531 { 532 struct pts_softc *psc = tty_softc(tp); 533 534 /* 535 * Clear conflicting flags. 536 */ 537 538 switch (event) { 539 case TIOCPKT_STOP: 540 psc->pts_pkt &= ~TIOCPKT_START; 541 break; 542 case TIOCPKT_START: 543 psc->pts_pkt &= ~TIOCPKT_STOP; 544 break; 545 case TIOCPKT_NOSTOP: 546 psc->pts_pkt &= ~TIOCPKT_DOSTOP; 547 break; 548 case TIOCPKT_DOSTOP: 549 psc->pts_pkt &= ~TIOCPKT_NOSTOP; 550 break; 551 } 552 553 psc->pts_pkt |= event; 554 ptsdrv_outwakeup(tp); 555 } 556 557 static void 558 ptsdrv_free(void *softc) 559 { 560 struct pts_softc *psc = softc; 561 562 /* Make device number available again. */ 563 if (psc->pts_unit >= 0) 564 free_unr(pts_pool, psc->pts_unit); 565 566 chgptscnt(psc->pts_uidinfo, -1, 0); 567 uifree(psc->pts_uidinfo); 568 569 #ifdef PTS_EXTERNAL 570 /* Destroy master device as well. */ 571 if (psc->pts_cdev != NULL) 572 destroy_dev_sched(psc->pts_cdev); 573 #endif /* PTS_EXTERNAL */ 574 575 free(psc, M_PTS); 576 } 577 578 static struct ttydevsw pts_class = { 579 .tsw_flags = TF_NOPREFIX, 580 .tsw_outwakeup = ptsdrv_outwakeup, 581 .tsw_inwakeup = ptsdrv_inwakeup, 582 .tsw_open = ptsdrv_open, 583 .tsw_close = ptsdrv_close, 584 .tsw_pktnotify = ptsdrv_pktnotify, 585 .tsw_free = ptsdrv_free, 586 }; 587 588 static int 589 pts_alloc(int fflags, struct thread *td, struct file *fp) 590 { 591 int unit, ok; 592 struct tty *tp; 593 struct pts_softc *psc; 594 struct proc *p = td->td_proc; 595 struct uidinfo *uid = td->td_ucred->cr_ruidinfo; 596 597 /* Resource limiting. */ 598 PROC_LOCK(p); 599 ok = chgptscnt(uid, 1, lim_cur(p, RLIMIT_NPTS)); 600 PROC_UNLOCK(p); 601 if (!ok) 602 return (EAGAIN); 603 604 /* Try to allocate a new pts unit number. */ 605 unit = alloc_unr(pts_pool); 606 if (unit < 0) { 607 chgptscnt(uid, -1, 0); 608 return (EAGAIN); 609 } 610 611 /* Allocate TTY and softc. */ 612 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 613 cv_init(&psc->pts_inwait, "pts inwait"); 614 cv_init(&psc->pts_outwait, "pts outwait"); 615 616 psc->pts_unit = unit; 617 psc->pts_uidinfo = uid; 618 uihold(uid); 619 620 tp = tty_alloc(&pts_class, psc, NULL); 621 622 /* Expose the slave device as well. */ 623 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit); 624 625 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 626 627 return (0); 628 } 629 630 #ifdef PTS_EXTERNAL 631 int 632 pts_alloc_external(int fflags, struct thread *td, struct file *fp, 633 struct cdev *dev, const char *name) 634 { 635 int ok; 636 struct tty *tp; 637 struct pts_softc *psc; 638 struct proc *p = td->td_proc; 639 struct uidinfo *uid = td->td_ucred->cr_ruidinfo; 640 641 /* Resource limiting. */ 642 PROC_LOCK(p); 643 ok = chgptscnt(uid, 1, lim_cur(p, RLIMIT_NPTS)); 644 PROC_UNLOCK(p); 645 if (!ok) 646 return (EAGAIN); 647 648 /* Allocate TTY and softc. */ 649 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 650 cv_init(&psc->pts_inwait, "pts inwait"); 651 cv_init(&psc->pts_outwait, "pts outwait"); 652 653 psc->pts_unit = -1; 654 psc->pts_cdev = dev; 655 psc->pts_uidinfo = uid; 656 uihold(uid); 657 658 tp = tty_alloc(&pts_class, psc, NULL); 659 660 /* Expose the slave device as well. */ 661 tty_makedev(tp, td->td_ucred, "%s", name); 662 663 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 664 665 return (0); 666 } 667 #endif /* PTS_EXTERNAL */ 668 669 int 670 posix_openpt(struct thread *td, struct posix_openpt_args *uap) 671 { 672 int error, fd; 673 struct file *fp; 674 675 /* 676 * POSIX states it's unspecified when other flags are passed. We 677 * don't allow this. 678 */ 679 if (uap->flags & ~(O_RDWR|O_NOCTTY)) 680 return (EINVAL); 681 682 error = falloc(td, &fp, &fd); 683 if (error) 684 return (error); 685 686 /* Allocate the actual pseudo-TTY. */ 687 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp); 688 if (error != 0) { 689 fdclose(td->td_proc->p_fd, fp, fd, td); 690 return (error); 691 } 692 693 /* Pass it back to userspace. */ 694 td->td_retval[0] = fd; 695 fdrop(fp, td); 696 697 return (0); 698 } 699 700 #if defined(PTS_COMPAT) || defined(PTS_LINUX) 701 static int 702 ptmx_fdopen(struct cdev *dev, int fflags, struct thread *td, struct file *fp) 703 { 704 int error; 705 706 error = pts_alloc(fflags & (FREAD|FWRITE), td, fp); 707 if (error != 0) 708 return (error); 709 710 return (0); 711 } 712 713 static struct cdevsw ptmx_cdevsw = { 714 .d_version = D_VERSION, 715 .d_fdopen = ptmx_fdopen, 716 .d_name = "ptmx", 717 }; 718 #endif /* PTS_COMPAT || PTS_LINUX */ 719 720 static void 721 pts_init(void *unused) 722 { 723 724 pts_pool = new_unrhdr(0, MAXPTSDEVS, NULL); 725 #if defined(PTS_COMPAT) || defined(PTS_LINUX) 726 make_dev(&ptmx_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "ptmx"); 727 #endif /* PTS_COMPAT || PTS_LINUX */ 728 } 729 730 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL); 731