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 /* Add compatibility bits for FreeBSD. */ 34 #define PTS_COMPAT 35 /* Add pty(4) compat bits. */ 36 #define PTS_EXTERNAL 37 /* Add bits to make Linux binaries work. */ 38 #define PTS_LINUX 39 40 #include <sys/param.h> 41 #include <sys/lock.h> 42 #include <sys/condvar.h> 43 #include <sys/conf.h> 44 #include <sys/fcntl.h> 45 #include <sys/file.h> 46 #include <sys/filedesc.h> 47 #include <sys/filio.h> 48 #include <sys/kernel.h> 49 #include <sys/limits.h> 50 #include <sys/malloc.h> 51 #include <sys/poll.h> 52 #include <sys/proc.h> 53 #include <sys/racct.h> 54 #include <sys/resourcevar.h> 55 #include <sys/serial.h> 56 #include <sys/stat.h> 57 #include <sys/syscall.h> 58 #include <sys/syscallsubr.h> 59 #include <sys/sysctl.h> 60 #include <sys/sysent.h> 61 #include <sys/sysproto.h> 62 #include <sys/systm.h> 63 #include <sys/tty.h> 64 #include <sys/ttycom.h> 65 #include <sys/user.h> 66 67 #include <machine/stdarg.h> 68 69 /* 70 * Our utmp(5) format is limited to 8-byte TTY line names. This means 71 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow 72 * users to increase this number, assuming they have manually increased 73 * UT_LINESIZE. 74 */ 75 static struct unrhdr *pts_pool; 76 77 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device"); 78 79 /* 80 * Per-PTS structure. 81 * 82 * List of locks 83 * (t) locked by tty_lock() 84 * (c) const until freeing 85 */ 86 struct pts_softc { 87 int pts_unit; /* (c) Device unit number. */ 88 unsigned int pts_flags; /* (t) Device flags. */ 89 #define PTS_PKT 0x1 /* Packet mode. */ 90 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */ 91 char pts_pkt; /* (t) Unread packet mode data. */ 92 93 struct cv pts_inwait; /* (t) Blocking write() on master. */ 94 struct selinfo pts_inpoll; /* (t) Select queue for write(). */ 95 struct cv pts_outwait; /* (t) Blocking read() on master. */ 96 struct selinfo pts_outpoll; /* (t) Select queue for read(). */ 97 98 #ifdef PTS_EXTERNAL 99 struct cdev *pts_cdev; /* (c) Master device node. */ 100 #endif /* PTS_EXTERNAL */ 101 102 struct ucred *pts_cred; /* (c) Resource limit. */ 103 }; 104 105 /* 106 * Controller-side file operations. 107 */ 108 109 static int 110 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 111 int flags, struct thread *td) 112 { 113 struct tty *tp = fp->f_data; 114 struct pts_softc *psc = tty_softc(tp); 115 int error = 0; 116 char pkt; 117 118 if (uio->uio_resid == 0) 119 return (0); 120 121 tty_lock(tp); 122 123 for (;;) { 124 /* 125 * Implement packet mode. When packet mode is turned on, 126 * the first byte contains a bitmask of events that 127 * occurred (start, stop, flush, window size, etc). 128 */ 129 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) { 130 pkt = psc->pts_pkt; 131 psc->pts_pkt = 0; 132 tty_unlock(tp); 133 134 error = ureadc(pkt, uio); 135 return (error); 136 } 137 138 /* 139 * Transmit regular data. 140 * 141 * XXX: We shouldn't use ttydisc_getc_poll()! Even 142 * though in this implementation, there is likely going 143 * to be data, we should just call ttydisc_getc_uio() 144 * and use its return value to sleep. 145 */ 146 if (ttydisc_getc_poll(tp)) { 147 if (psc->pts_flags & PTS_PKT) { 148 /* 149 * XXX: Small race. Fortunately PTY 150 * consumers aren't multithreaded. 151 */ 152 153 tty_unlock(tp); 154 error = ureadc(TIOCPKT_DATA, uio); 155 if (error) 156 return (error); 157 tty_lock(tp); 158 } 159 160 error = ttydisc_getc_uio(tp, uio); 161 break; 162 } 163 164 /* Maybe the device isn't used anyway. */ 165 if (psc->pts_flags & PTS_FINISHED) 166 break; 167 168 /* Wait for more data. */ 169 if (fp->f_flag & O_NONBLOCK) { 170 error = EWOULDBLOCK; 171 break; 172 } 173 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx); 174 if (error != 0) 175 break; 176 } 177 178 tty_unlock(tp); 179 180 return (error); 181 } 182 183 static int 184 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 185 int flags, struct thread *td) 186 { 187 struct tty *tp = fp->f_data; 188 struct pts_softc *psc = tty_softc(tp); 189 char ib[256], *ibstart; 190 size_t iblen, rintlen; 191 int error = 0; 192 193 if (uio->uio_resid == 0) 194 return (0); 195 196 for (;;) { 197 ibstart = ib; 198 iblen = MIN(uio->uio_resid, sizeof ib); 199 error = uiomove(ib, iblen, uio); 200 201 tty_lock(tp); 202 if (error != 0) { 203 iblen = 0; 204 goto done; 205 } 206 207 /* 208 * When possible, avoid the slow path. rint_bypass() 209 * copies all input to the input queue at once. 210 */ 211 MPASS(iblen > 0); 212 do { 213 rintlen = ttydisc_rint_simple(tp, ibstart, iblen); 214 ibstart += rintlen; 215 iblen -= rintlen; 216 if (iblen == 0) { 217 /* All data written. */ 218 break; 219 } 220 221 /* Maybe the device isn't used anyway. */ 222 if (psc->pts_flags & PTS_FINISHED) { 223 error = EIO; 224 goto done; 225 } 226 227 /* Wait for more data. */ 228 if (fp->f_flag & O_NONBLOCK) { 229 error = EWOULDBLOCK; 230 goto done; 231 } 232 233 /* Wake up users on the slave side. */ 234 ttydisc_rint_done(tp); 235 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx); 236 if (error != 0) 237 goto done; 238 } while (iblen > 0); 239 240 if (uio->uio_resid == 0) 241 break; 242 tty_unlock(tp); 243 } 244 245 done: ttydisc_rint_done(tp); 246 tty_unlock(tp); 247 248 /* 249 * Don't account for the part of the buffer that we couldn't 250 * pass to the TTY. 251 */ 252 uio->uio_resid += iblen; 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 FIODTYPE: 266 *(int *)data = D_TTY; 267 return (0); 268 case FIONBIO: 269 /* This device supports non-blocking operation. */ 270 return (0); 271 case FIONREAD: 272 tty_lock(tp); 273 if (psc->pts_flags & PTS_FINISHED) { 274 /* Force read() to be called. */ 275 *(int *)data = 1; 276 } else { 277 *(int *)data = ttydisc_getc_poll(tp); 278 } 279 tty_unlock(tp); 280 return (0); 281 case FIODGNAME: { 282 struct fiodgname_arg *fgn; 283 const char *p; 284 int i; 285 286 /* Reverse device name lookups, for ptsname() and ttyname(). */ 287 fgn = data; 288 p = tty_devname(tp); 289 i = strlen(p) + 1; 290 if (i > fgn->len) 291 return (EINVAL); 292 return copyout(p, fgn->buf, i); 293 } 294 295 /* 296 * We need to implement TIOCGPGRP and TIOCGSID here again. When 297 * called on the pseudo-terminal master, it should not check if 298 * the terminal is the foreground terminal of the calling 299 * process. 300 * 301 * TIOCGETA is also implemented here. Various Linux PTY routines 302 * often call isatty(), which is implemented by tcgetattr(). 303 */ 304 #ifdef PTS_LINUX 305 case TIOCGETA: 306 /* Obtain terminal flags through tcgetattr(). */ 307 tty_lock(tp); 308 *(struct termios*)data = tp->t_termios; 309 tty_unlock(tp); 310 return (0); 311 #endif /* PTS_LINUX */ 312 case TIOCSETAF: 313 case TIOCSETAW: 314 /* 315 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and 316 * TCSADRAIN into something different. If an application would 317 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may 318 * deadlock waiting for all data to be read. 319 */ 320 cmd = TIOCSETA; 321 break; 322 #if defined(PTS_COMPAT) || defined(PTS_LINUX) 323 case TIOCGPTN: 324 /* 325 * Get the device unit number. 326 */ 327 if (psc->pts_unit < 0) 328 return (ENOTTY); 329 *(unsigned int *)data = psc->pts_unit; 330 return (0); 331 #endif /* PTS_COMPAT || PTS_LINUX */ 332 case TIOCGPGRP: 333 /* Get the foreground process group ID. */ 334 tty_lock(tp); 335 if (tp->t_pgrp != NULL) 336 *(int *)data = tp->t_pgrp->pg_id; 337 else 338 *(int *)data = NO_PID; 339 tty_unlock(tp); 340 return (0); 341 case TIOCGSID: 342 /* Get the session leader process ID. */ 343 tty_lock(tp); 344 if (tp->t_session == NULL) 345 error = ENOTTY; 346 else 347 *(int *)data = tp->t_session->s_sid; 348 tty_unlock(tp); 349 return (error); 350 case TIOCPTMASTER: 351 /* Yes, we are a pseudo-terminal master. */ 352 return (0); 353 case TIOCSIG: 354 /* Signal the foreground process group. */ 355 sig = *(int *)data; 356 if (sig < 1 || sig >= NSIG) 357 return (EINVAL); 358 359 tty_lock(tp); 360 tty_signal_pgrp(tp, sig); 361 tty_unlock(tp); 362 return (0); 363 case TIOCPKT: 364 /* Enable/disable packet mode. */ 365 tty_lock(tp); 366 if (*(int *)data) 367 psc->pts_flags |= PTS_PKT; 368 else 369 psc->pts_flags &= ~PTS_PKT; 370 tty_unlock(tp); 371 return (0); 372 } 373 374 /* Just redirect this ioctl to the slave device. */ 375 tty_lock(tp); 376 error = tty_ioctl(tp, cmd, data, fp->f_flag, td); 377 tty_unlock(tp); 378 if (error == ENOIOCTL) 379 error = ENOTTY; 380 381 return (error); 382 } 383 384 static int 385 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred, 386 struct thread *td) 387 { 388 struct tty *tp = fp->f_data; 389 struct pts_softc *psc = tty_softc(tp); 390 int revents = 0; 391 392 tty_lock(tp); 393 394 if (psc->pts_flags & PTS_FINISHED) { 395 /* Slave device is not opened. */ 396 tty_unlock(tp); 397 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP); 398 } 399 400 if (events & (POLLIN|POLLRDNORM)) { 401 /* See if we can getc something. */ 402 if (ttydisc_getc_poll(tp) || 403 (psc->pts_flags & PTS_PKT && psc->pts_pkt)) 404 revents |= events & (POLLIN|POLLRDNORM); 405 } 406 if (events & (POLLOUT|POLLWRNORM)) { 407 /* See if we can rint something. */ 408 if (ttydisc_rint_poll(tp)) 409 revents |= events & (POLLOUT|POLLWRNORM); 410 } 411 412 /* 413 * No need to check for POLLHUP here. This device cannot be used 414 * as a callout device, which means we always have a carrier, 415 * because the master is. 416 */ 417 418 if (revents == 0) { 419 /* 420 * This code might look misleading, but the naming of 421 * poll events on this side is the opposite of the slave 422 * device. 423 */ 424 if (events & (POLLIN|POLLRDNORM)) 425 selrecord(td, &psc->pts_outpoll); 426 if (events & (POLLOUT|POLLWRNORM)) 427 selrecord(td, &psc->pts_inpoll); 428 } 429 430 tty_unlock(tp); 431 432 return (revents); 433 } 434 435 /* 436 * kqueue support. 437 */ 438 439 static void 440 pts_kqops_read_detach(struct knote *kn) 441 { 442 struct file *fp = kn->kn_fp; 443 struct tty *tp = fp->f_data; 444 struct pts_softc *psc = tty_softc(tp); 445 446 knlist_remove(&psc->pts_outpoll.si_note, kn, 0); 447 } 448 449 static int 450 pts_kqops_read_event(struct knote *kn, long hint) 451 { 452 struct file *fp = kn->kn_fp; 453 struct tty *tp = fp->f_data; 454 struct pts_softc *psc = tty_softc(tp); 455 456 if (psc->pts_flags & PTS_FINISHED) { 457 kn->kn_flags |= EV_EOF; 458 return (1); 459 } else { 460 kn->kn_data = ttydisc_getc_poll(tp); 461 return (kn->kn_data > 0); 462 } 463 } 464 465 static void 466 pts_kqops_write_detach(struct knote *kn) 467 { 468 struct file *fp = kn->kn_fp; 469 struct tty *tp = fp->f_data; 470 struct pts_softc *psc = tty_softc(tp); 471 472 knlist_remove(&psc->pts_inpoll.si_note, kn, 0); 473 } 474 475 static int 476 pts_kqops_write_event(struct knote *kn, long hint) 477 { 478 struct file *fp = kn->kn_fp; 479 struct tty *tp = fp->f_data; 480 struct pts_softc *psc = tty_softc(tp); 481 482 if (psc->pts_flags & PTS_FINISHED) { 483 kn->kn_flags |= EV_EOF; 484 return (1); 485 } else { 486 kn->kn_data = ttydisc_rint_poll(tp); 487 return (kn->kn_data > 0); 488 } 489 } 490 491 static struct filterops pts_kqops_read = { 492 .f_isfd = 1, 493 .f_detach = pts_kqops_read_detach, 494 .f_event = pts_kqops_read_event, 495 }; 496 static struct filterops pts_kqops_write = { 497 .f_isfd = 1, 498 .f_detach = pts_kqops_write_detach, 499 .f_event = pts_kqops_write_event, 500 }; 501 502 static int 503 ptsdev_kqfilter(struct file *fp, struct knote *kn) 504 { 505 struct tty *tp = fp->f_data; 506 struct pts_softc *psc = tty_softc(tp); 507 int error = 0; 508 509 tty_lock(tp); 510 511 switch (kn->kn_filter) { 512 case EVFILT_READ: 513 kn->kn_fop = &pts_kqops_read; 514 knlist_add(&psc->pts_outpoll.si_note, kn, 1); 515 break; 516 case EVFILT_WRITE: 517 kn->kn_fop = &pts_kqops_write; 518 knlist_add(&psc->pts_inpoll.si_note, kn, 1); 519 break; 520 default: 521 error = EINVAL; 522 break; 523 } 524 525 tty_unlock(tp); 526 return (error); 527 } 528 529 static int 530 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 531 struct thread *td) 532 { 533 struct tty *tp = fp->f_data; 534 #ifdef PTS_EXTERNAL 535 struct pts_softc *psc = tty_softc(tp); 536 #endif /* PTS_EXTERNAL */ 537 struct cdev *dev = tp->t_dev; 538 539 /* 540 * According to POSIX, we must implement an fstat(). This also 541 * makes this implementation compatible with Linux binaries, 542 * because Linux calls fstat() on the pseudo-terminal master to 543 * obtain st_rdev. 544 * 545 * XXX: POSIX also mentions we must fill in st_dev, but how? 546 */ 547 548 bzero(sb, sizeof *sb); 549 #ifdef PTS_EXTERNAL 550 if (psc->pts_cdev != NULL) 551 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev); 552 else 553 #endif /* PTS_EXTERNAL */ 554 sb->st_ino = sb->st_rdev = tty_udev(tp); 555 556 sb->st_atim = dev->si_atime; 557 sb->st_ctim = dev->si_ctime; 558 sb->st_mtim = dev->si_mtime; 559 sb->st_uid = dev->si_uid; 560 sb->st_gid = dev->si_gid; 561 sb->st_mode = dev->si_mode | S_IFCHR; 562 563 return (0); 564 } 565 566 static int 567 ptsdev_close(struct file *fp, struct thread *td) 568 { 569 struct tty *tp = fp->f_data; 570 571 /* Deallocate TTY device. */ 572 tty_lock(tp); 573 tty_rel_gone(tp); 574 575 /* 576 * Open of /dev/ptmx or /dev/ptyXX changes the type of file 577 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode 578 * use count, we need to decrement it, and possibly do other 579 * required cleanup. 580 */ 581 if (fp->f_vnode != NULL) 582 return (vnops.fo_close(fp, td)); 583 584 return (0); 585 } 586 587 static int 588 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 589 { 590 struct tty *tp; 591 592 kif->kf_type = KF_TYPE_PTS; 593 tp = fp->f_data; 594 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp); 595 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path)); 596 return (0); 597 } 598 599 static struct fileops ptsdev_ops = { 600 .fo_read = ptsdev_read, 601 .fo_write = ptsdev_write, 602 .fo_truncate = invfo_truncate, 603 .fo_ioctl = ptsdev_ioctl, 604 .fo_poll = ptsdev_poll, 605 .fo_kqfilter = ptsdev_kqfilter, 606 .fo_stat = ptsdev_stat, 607 .fo_close = ptsdev_close, 608 .fo_chmod = invfo_chmod, 609 .fo_chown = invfo_chown, 610 .fo_sendfile = invfo_sendfile, 611 .fo_fill_kinfo = ptsdev_fill_kinfo, 612 .fo_flags = DFLAG_PASSABLE, 613 }; 614 615 /* 616 * Driver-side hooks. 617 */ 618 619 static void 620 ptsdrv_outwakeup(struct tty *tp) 621 { 622 struct pts_softc *psc = tty_softc(tp); 623 624 cv_broadcast(&psc->pts_outwait); 625 selwakeup(&psc->pts_outpoll); 626 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0); 627 } 628 629 static void 630 ptsdrv_inwakeup(struct tty *tp) 631 { 632 struct pts_softc *psc = tty_softc(tp); 633 634 cv_broadcast(&psc->pts_inwait); 635 selwakeup(&psc->pts_inpoll); 636 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0); 637 } 638 639 static int 640 ptsdrv_open(struct tty *tp) 641 { 642 struct pts_softc *psc = tty_softc(tp); 643 644 psc->pts_flags &= ~PTS_FINISHED; 645 646 return (0); 647 } 648 649 static void 650 ptsdrv_close(struct tty *tp) 651 { 652 struct pts_softc *psc = tty_softc(tp); 653 654 /* Wake up any blocked readers/writers. */ 655 psc->pts_flags |= PTS_FINISHED; 656 ptsdrv_outwakeup(tp); 657 ptsdrv_inwakeup(tp); 658 } 659 660 static void 661 ptsdrv_pktnotify(struct tty *tp, char event) 662 { 663 struct pts_softc *psc = tty_softc(tp); 664 665 /* 666 * Clear conflicting flags. 667 */ 668 669 switch (event) { 670 case TIOCPKT_STOP: 671 psc->pts_pkt &= ~TIOCPKT_START; 672 break; 673 case TIOCPKT_START: 674 psc->pts_pkt &= ~TIOCPKT_STOP; 675 break; 676 case TIOCPKT_NOSTOP: 677 psc->pts_pkt &= ~TIOCPKT_DOSTOP; 678 break; 679 case TIOCPKT_DOSTOP: 680 psc->pts_pkt &= ~TIOCPKT_NOSTOP; 681 break; 682 } 683 684 psc->pts_pkt |= event; 685 ptsdrv_outwakeup(tp); 686 } 687 688 static void 689 ptsdrv_free(void *softc) 690 { 691 struct pts_softc *psc = softc; 692 693 /* Make device number available again. */ 694 if (psc->pts_unit >= 0) 695 free_unr(pts_pool, psc->pts_unit); 696 697 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0); 698 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1); 699 crfree(psc->pts_cred); 700 701 seldrain(&psc->pts_inpoll); 702 seldrain(&psc->pts_outpoll); 703 knlist_destroy(&psc->pts_inpoll.si_note); 704 knlist_destroy(&psc->pts_outpoll.si_note); 705 706 #ifdef PTS_EXTERNAL 707 /* Destroy master device as well. */ 708 if (psc->pts_cdev != NULL) 709 destroy_dev_sched(psc->pts_cdev); 710 #endif /* PTS_EXTERNAL */ 711 712 free(psc, M_PTS); 713 } 714 715 static struct ttydevsw pts_class = { 716 .tsw_flags = TF_NOPREFIX, 717 .tsw_outwakeup = ptsdrv_outwakeup, 718 .tsw_inwakeup = ptsdrv_inwakeup, 719 .tsw_open = ptsdrv_open, 720 .tsw_close = ptsdrv_close, 721 .tsw_pktnotify = ptsdrv_pktnotify, 722 .tsw_free = ptsdrv_free, 723 }; 724 725 #ifndef PTS_EXTERNAL 726 static 727 #endif /* !PTS_EXTERNAL */ 728 int 729 pts_alloc(int fflags, struct thread *td, struct file *fp) 730 { 731 int unit, ok, error; 732 struct tty *tp; 733 struct pts_softc *psc; 734 struct proc *p = td->td_proc; 735 struct ucred *cred = td->td_ucred; 736 737 /* Resource limiting. */ 738 PROC_LOCK(p); 739 error = racct_add(p, RACCT_NPTS, 1); 740 if (error != 0) { 741 PROC_UNLOCK(p); 742 return (EAGAIN); 743 } 744 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 745 if (!ok) { 746 racct_sub(p, RACCT_NPTS, 1); 747 PROC_UNLOCK(p); 748 return (EAGAIN); 749 } 750 PROC_UNLOCK(p); 751 752 /* Try to allocate a new pts unit number. */ 753 unit = alloc_unr(pts_pool); 754 if (unit < 0) { 755 racct_sub(p, RACCT_NPTS, 1); 756 chgptscnt(cred->cr_ruidinfo, -1, 0); 757 return (EAGAIN); 758 } 759 760 /* Allocate TTY and softc. */ 761 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 762 cv_init(&psc->pts_inwait, "ptsin"); 763 cv_init(&psc->pts_outwait, "ptsout"); 764 765 psc->pts_unit = unit; 766 psc->pts_cred = crhold(cred); 767 768 tp = tty_alloc(&pts_class, psc); 769 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 770 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 771 772 /* Expose the slave device as well. */ 773 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit); 774 775 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 776 777 return (0); 778 } 779 780 #ifdef PTS_EXTERNAL 781 int 782 pts_alloc_external(int fflags, struct thread *td, struct file *fp, 783 struct cdev *dev, const char *name) 784 { 785 int ok, error; 786 struct tty *tp; 787 struct pts_softc *psc; 788 struct proc *p = td->td_proc; 789 struct ucred *cred = td->td_ucred; 790 791 /* Resource limiting. */ 792 PROC_LOCK(p); 793 error = racct_add(p, RACCT_NPTS, 1); 794 if (error != 0) { 795 PROC_UNLOCK(p); 796 return (EAGAIN); 797 } 798 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 799 if (!ok) { 800 racct_sub(p, RACCT_NPTS, 1); 801 PROC_UNLOCK(p); 802 return (EAGAIN); 803 } 804 PROC_UNLOCK(p); 805 806 /* Allocate TTY and softc. */ 807 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 808 cv_init(&psc->pts_inwait, "ptsin"); 809 cv_init(&psc->pts_outwait, "ptsout"); 810 811 psc->pts_unit = -1; 812 psc->pts_cdev = dev; 813 psc->pts_cred = crhold(cred); 814 815 tp = tty_alloc(&pts_class, psc); 816 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 817 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 818 819 /* Expose the slave device as well. */ 820 tty_makedev(tp, td->td_ucred, "%s", name); 821 822 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 823 824 return (0); 825 } 826 #endif /* PTS_EXTERNAL */ 827 828 int 829 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap) 830 { 831 int error, fd; 832 struct file *fp; 833 834 /* 835 * POSIX states it's unspecified when other flags are passed. We 836 * don't allow this. 837 */ 838 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC)) 839 return (EINVAL); 840 841 error = falloc(td, &fp, &fd, uap->flags); 842 if (error) 843 return (error); 844 845 /* Allocate the actual pseudo-TTY. */ 846 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp); 847 if (error != 0) { 848 fdclose(td, fp, fd); 849 fdrop(fp, td); 850 return (error); 851 } 852 853 /* Pass it back to userspace. */ 854 td->td_retval[0] = fd; 855 fdrop(fp, td); 856 857 return (0); 858 } 859 860 static void 861 pts_init(void *unused) 862 { 863 864 pts_pool = new_unrhdr(0, INT_MAX, NULL); 865 } 866 867 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL); 868