1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org> 5 * All rights reserved. 6 * 7 * Portions of this software were developed under sponsorship from Snow 8 * B.V., the Netherlands. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 /* Add compatibility bits for FreeBSD. */ 36 #define PTS_COMPAT 37 /* Add pty(4) compat bits. */ 38 #define PTS_EXTERNAL 39 /* Add bits to make Linux binaries work. */ 40 #define PTS_LINUX 41 42 #include <sys/param.h> 43 #include <sys/lock.h> 44 #include <sys/condvar.h> 45 #include <sys/conf.h> 46 #include <sys/fcntl.h> 47 #include <sys/file.h> 48 #include <sys/filedesc.h> 49 #include <sys/filio.h> 50 #include <sys/kernel.h> 51 #include <sys/limits.h> 52 #include <sys/malloc.h> 53 #include <sys/poll.h> 54 #include <sys/proc.h> 55 #include <sys/racct.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/sysctl.h> 62 #include <sys/sysent.h> 63 #include <sys/sysproto.h> 64 #include <sys/systm.h> 65 #include <sys/tty.h> 66 #include <sys/ttycom.h> 67 #include <sys/user.h> 68 69 #include <machine/stdarg.h> 70 71 /* 72 * Our utmp(5) format is limited to 8-byte TTY line names. This means 73 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow 74 * users to increase this number, assuming they have manually increased 75 * UT_LINESIZE. 76 */ 77 static struct unrhdr *pts_pool; 78 79 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device"); 80 81 /* 82 * Per-PTS structure. 83 * 84 * List of locks 85 * (t) locked by tty_lock() 86 * (c) const until freeing 87 */ 88 struct pts_softc { 89 int pts_unit; /* (c) Device unit number. */ 90 unsigned int pts_flags; /* (t) Device flags. */ 91 #define PTS_PKT 0x1 /* Packet mode. */ 92 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */ 93 char pts_pkt; /* (t) Unread packet mode data. */ 94 95 struct cv pts_inwait; /* (t) Blocking write() on master. */ 96 struct selinfo pts_inpoll; /* (t) Select queue for write(). */ 97 struct cv pts_outwait; /* (t) Blocking read() on master. */ 98 struct selinfo pts_outpoll; /* (t) Select queue for read(). */ 99 100 #ifdef PTS_EXTERNAL 101 struct cdev *pts_cdev; /* (c) Master device node. */ 102 #endif /* PTS_EXTERNAL */ 103 104 struct ucred *pts_cred; /* (c) Resource limit. */ 105 }; 106 107 /* 108 * Controller-side file operations. 109 */ 110 111 static int 112 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 113 int flags, struct thread *td) 114 { 115 struct tty *tp = fp->f_data; 116 struct pts_softc *psc = tty_softc(tp); 117 int error = 0; 118 char pkt; 119 120 if (uio->uio_resid == 0) 121 return (0); 122 123 tty_lock(tp); 124 125 for (;;) { 126 /* 127 * Implement packet mode. When packet mode is turned on, 128 * the first byte contains a bitmask of events that 129 * occurred (start, stop, flush, window size, etc). 130 */ 131 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) { 132 pkt = psc->pts_pkt; 133 psc->pts_pkt = 0; 134 tty_unlock(tp); 135 136 error = ureadc(pkt, uio); 137 return (error); 138 } 139 140 /* 141 * Transmit regular data. 142 * 143 * XXX: We shouldn't use ttydisc_getc_poll()! Even 144 * though in this implementation, there is likely going 145 * to be data, we should just call ttydisc_getc_uio() 146 * and use its return value to sleep. 147 */ 148 if (ttydisc_getc_poll(tp)) { 149 if (psc->pts_flags & PTS_PKT) { 150 /* 151 * XXX: Small race. Fortunately PTY 152 * consumers aren't multithreaded. 153 */ 154 155 tty_unlock(tp); 156 error = ureadc(TIOCPKT_DATA, uio); 157 if (error) 158 return (error); 159 tty_lock(tp); 160 } 161 162 error = ttydisc_getc_uio(tp, uio); 163 break; 164 } 165 166 /* Maybe the device isn't used anyway. */ 167 if (psc->pts_flags & PTS_FINISHED) 168 break; 169 170 /* Wait for more data. */ 171 if (fp->f_flag & O_NONBLOCK) { 172 error = EWOULDBLOCK; 173 break; 174 } 175 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx); 176 if (error != 0) 177 break; 178 } 179 180 tty_unlock(tp); 181 182 return (error); 183 } 184 185 static int 186 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 187 int flags, struct thread *td) 188 { 189 struct tty *tp = fp->f_data; 190 struct pts_softc *psc = tty_softc(tp); 191 char ib[256], *ibstart; 192 size_t iblen, rintlen; 193 int error = 0; 194 195 if (uio->uio_resid == 0) 196 return (0); 197 198 for (;;) { 199 ibstart = ib; 200 iblen = MIN(uio->uio_resid, sizeof ib); 201 error = uiomove(ib, iblen, uio); 202 203 tty_lock(tp); 204 if (error != 0) { 205 iblen = 0; 206 goto done; 207 } 208 209 /* 210 * When possible, avoid the slow path. rint_bypass() 211 * copies all input to the input queue at once. 212 */ 213 MPASS(iblen > 0); 214 do { 215 rintlen = ttydisc_rint_simple(tp, ibstart, iblen); 216 ibstart += rintlen; 217 iblen -= rintlen; 218 if (iblen == 0) { 219 /* All data written. */ 220 break; 221 } 222 223 /* Maybe the device isn't used anyway. */ 224 if (psc->pts_flags & PTS_FINISHED) { 225 error = EIO; 226 goto done; 227 } 228 229 /* Wait for more data. */ 230 if (fp->f_flag & O_NONBLOCK) { 231 error = EWOULDBLOCK; 232 goto done; 233 } 234 235 /* Wake up users on the slave side. */ 236 ttydisc_rint_done(tp); 237 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx); 238 if (error != 0) 239 goto done; 240 } while (iblen > 0); 241 242 if (uio->uio_resid == 0) 243 break; 244 tty_unlock(tp); 245 } 246 247 done: ttydisc_rint_done(tp); 248 tty_unlock(tp); 249 250 /* 251 * Don't account for the part of the buffer that we couldn't 252 * pass to the TTY. 253 */ 254 uio->uio_resid += iblen; 255 return (error); 256 } 257 258 static int 259 ptsdev_ioctl(struct file *fp, u_long cmd, void *data, 260 struct ucred *active_cred, struct thread *td) 261 { 262 struct tty *tp = fp->f_data; 263 struct pts_softc *psc = tty_softc(tp); 264 int error = 0, sig; 265 266 switch (cmd) { 267 case FIODTYPE: 268 *(int *)data = D_TTY; 269 return (0); 270 case FIONBIO: 271 /* This device supports non-blocking operation. */ 272 return (0); 273 case FIONREAD: 274 tty_lock(tp); 275 if (psc->pts_flags & PTS_FINISHED) { 276 /* Force read() to be called. */ 277 *(int *)data = 1; 278 } else { 279 *(int *)data = ttydisc_getc_poll(tp); 280 } 281 tty_unlock(tp); 282 return (0); 283 case FIODGNAME: { 284 struct fiodgname_arg *fgn; 285 const char *p; 286 int i; 287 288 /* Reverse device name lookups, for ptsname() and ttyname(). */ 289 fgn = data; 290 p = tty_devname(tp); 291 i = strlen(p) + 1; 292 if (i > fgn->len) 293 return (EINVAL); 294 return copyout(p, fgn->buf, i); 295 } 296 297 /* 298 * We need to implement TIOCGPGRP and TIOCGSID here again. When 299 * called on the pseudo-terminal master, it should not check if 300 * the terminal is the foreground terminal of the calling 301 * process. 302 * 303 * TIOCGETA is also implemented here. Various Linux PTY routines 304 * often call isatty(), which is implemented by tcgetattr(). 305 */ 306 #ifdef PTS_LINUX 307 case TIOCGETA: 308 /* Obtain terminal flags through tcgetattr(). */ 309 tty_lock(tp); 310 *(struct termios*)data = tp->t_termios; 311 tty_unlock(tp); 312 return (0); 313 #endif /* PTS_LINUX */ 314 case TIOCSETAF: 315 case TIOCSETAW: 316 /* 317 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and 318 * TCSADRAIN into something different. If an application would 319 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may 320 * deadlock waiting for all data to be read. 321 */ 322 cmd = TIOCSETA; 323 break; 324 #if defined(PTS_COMPAT) || defined(PTS_LINUX) 325 case TIOCGPTN: 326 /* 327 * Get the device unit number. 328 */ 329 if (psc->pts_unit < 0) 330 return (ENOTTY); 331 *(unsigned int *)data = psc->pts_unit; 332 return (0); 333 #endif /* PTS_COMPAT || PTS_LINUX */ 334 case TIOCGPGRP: 335 /* Get the foreground process group ID. */ 336 tty_lock(tp); 337 if (tp->t_pgrp != NULL) 338 *(int *)data = tp->t_pgrp->pg_id; 339 else 340 *(int *)data = NO_PID; 341 tty_unlock(tp); 342 return (0); 343 case TIOCGSID: 344 /* Get the session leader process ID. */ 345 tty_lock(tp); 346 if (tp->t_session == NULL) 347 error = ENOTTY; 348 else 349 *(int *)data = tp->t_session->s_sid; 350 tty_unlock(tp); 351 return (error); 352 case TIOCPTMASTER: 353 /* Yes, we are a pseudo-terminal master. */ 354 return (0); 355 case TIOCSIG: 356 /* Signal the foreground process group. */ 357 sig = *(int *)data; 358 if (sig < 1 || sig >= NSIG) 359 return (EINVAL); 360 361 tty_lock(tp); 362 tty_signal_pgrp(tp, sig); 363 tty_unlock(tp); 364 return (0); 365 case TIOCPKT: 366 /* Enable/disable packet mode. */ 367 tty_lock(tp); 368 if (*(int *)data) 369 psc->pts_flags |= PTS_PKT; 370 else 371 psc->pts_flags &= ~PTS_PKT; 372 tty_unlock(tp); 373 return (0); 374 } 375 376 /* Just redirect this ioctl to the slave device. */ 377 tty_lock(tp); 378 error = tty_ioctl(tp, cmd, data, fp->f_flag, td); 379 tty_unlock(tp); 380 if (error == ENOIOCTL) 381 error = ENOTTY; 382 383 return (error); 384 } 385 386 static int 387 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred, 388 struct thread *td) 389 { 390 struct tty *tp = fp->f_data; 391 struct pts_softc *psc = tty_softc(tp); 392 int revents = 0; 393 394 tty_lock(tp); 395 396 if (psc->pts_flags & PTS_FINISHED) { 397 /* Slave device is not opened. */ 398 tty_unlock(tp); 399 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP); 400 } 401 402 if (events & (POLLIN|POLLRDNORM)) { 403 /* See if we can getc something. */ 404 if (ttydisc_getc_poll(tp) || 405 (psc->pts_flags & PTS_PKT && psc->pts_pkt)) 406 revents |= events & (POLLIN|POLLRDNORM); 407 } 408 if (events & (POLLOUT|POLLWRNORM)) { 409 /* See if we can rint something. */ 410 if (ttydisc_rint_poll(tp)) 411 revents |= events & (POLLOUT|POLLWRNORM); 412 } 413 414 /* 415 * No need to check for POLLHUP here. This device cannot be used 416 * as a callout device, which means we always have a carrier, 417 * because the master is. 418 */ 419 420 if (revents == 0) { 421 /* 422 * This code might look misleading, but the naming of 423 * poll events on this side is the opposite of the slave 424 * device. 425 */ 426 if (events & (POLLIN|POLLRDNORM)) 427 selrecord(td, &psc->pts_outpoll); 428 if (events & (POLLOUT|POLLWRNORM)) 429 selrecord(td, &psc->pts_inpoll); 430 } 431 432 tty_unlock(tp); 433 434 return (revents); 435 } 436 437 /* 438 * kqueue support. 439 */ 440 441 static void 442 pts_kqops_read_detach(struct knote *kn) 443 { 444 struct file *fp = kn->kn_fp; 445 struct tty *tp = fp->f_data; 446 struct pts_softc *psc = tty_softc(tp); 447 448 knlist_remove(&psc->pts_outpoll.si_note, kn, 0); 449 } 450 451 static int 452 pts_kqops_read_event(struct knote *kn, long hint) 453 { 454 struct file *fp = kn->kn_fp; 455 struct tty *tp = fp->f_data; 456 struct pts_softc *psc = tty_softc(tp); 457 458 if (psc->pts_flags & PTS_FINISHED) { 459 kn->kn_flags |= EV_EOF; 460 return (1); 461 } else { 462 kn->kn_data = ttydisc_getc_poll(tp); 463 return (kn->kn_data > 0); 464 } 465 } 466 467 static void 468 pts_kqops_write_detach(struct knote *kn) 469 { 470 struct file *fp = kn->kn_fp; 471 struct tty *tp = fp->f_data; 472 struct pts_softc *psc = tty_softc(tp); 473 474 knlist_remove(&psc->pts_inpoll.si_note, kn, 0); 475 } 476 477 static int 478 pts_kqops_write_event(struct knote *kn, long hint) 479 { 480 struct file *fp = kn->kn_fp; 481 struct tty *tp = fp->f_data; 482 struct pts_softc *psc = tty_softc(tp); 483 484 if (psc->pts_flags & PTS_FINISHED) { 485 kn->kn_flags |= EV_EOF; 486 return (1); 487 } else { 488 kn->kn_data = ttydisc_rint_poll(tp); 489 return (kn->kn_data > 0); 490 } 491 } 492 493 static struct filterops pts_kqops_read = { 494 .f_isfd = 1, 495 .f_detach = pts_kqops_read_detach, 496 .f_event = pts_kqops_read_event, 497 }; 498 static struct filterops pts_kqops_write = { 499 .f_isfd = 1, 500 .f_detach = pts_kqops_write_detach, 501 .f_event = pts_kqops_write_event, 502 }; 503 504 static int 505 ptsdev_kqfilter(struct file *fp, struct knote *kn) 506 { 507 struct tty *tp = fp->f_data; 508 struct pts_softc *psc = tty_softc(tp); 509 int error = 0; 510 511 tty_lock(tp); 512 513 switch (kn->kn_filter) { 514 case EVFILT_READ: 515 kn->kn_fop = &pts_kqops_read; 516 knlist_add(&psc->pts_outpoll.si_note, kn, 1); 517 break; 518 case EVFILT_WRITE: 519 kn->kn_fop = &pts_kqops_write; 520 knlist_add(&psc->pts_inpoll.si_note, kn, 1); 521 break; 522 default: 523 error = EINVAL; 524 break; 525 } 526 527 tty_unlock(tp); 528 return (error); 529 } 530 531 static int 532 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 533 struct thread *td) 534 { 535 struct tty *tp = fp->f_data; 536 #ifdef PTS_EXTERNAL 537 struct pts_softc *psc = tty_softc(tp); 538 #endif /* PTS_EXTERNAL */ 539 struct cdev *dev = tp->t_dev; 540 541 /* 542 * According to POSIX, we must implement an fstat(). This also 543 * makes this implementation compatible with Linux binaries, 544 * because Linux calls fstat() on the pseudo-terminal master to 545 * obtain st_rdev. 546 * 547 * XXX: POSIX also mentions we must fill in st_dev, but how? 548 */ 549 550 bzero(sb, sizeof *sb); 551 #ifdef PTS_EXTERNAL 552 if (psc->pts_cdev != NULL) 553 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev); 554 else 555 #endif /* PTS_EXTERNAL */ 556 sb->st_ino = sb->st_rdev = tty_udev(tp); 557 558 sb->st_atim = dev->si_atime; 559 sb->st_ctim = dev->si_ctime; 560 sb->st_mtim = dev->si_mtime; 561 sb->st_uid = dev->si_uid; 562 sb->st_gid = dev->si_gid; 563 sb->st_mode = dev->si_mode | S_IFCHR; 564 565 return (0); 566 } 567 568 static int 569 ptsdev_close(struct file *fp, struct thread *td) 570 { 571 struct tty *tp = fp->f_data; 572 573 /* Deallocate TTY device. */ 574 tty_lock(tp); 575 tty_rel_gone(tp); 576 577 /* 578 * Open of /dev/ptmx or /dev/ptyXX changes the type of file 579 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode 580 * use count, we need to decrement it, and possibly do other 581 * required cleanup. 582 */ 583 if (fp->f_vnode != NULL) 584 return (vnops.fo_close(fp, td)); 585 586 return (0); 587 } 588 589 static int 590 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 591 { 592 struct tty *tp; 593 594 kif->kf_type = KF_TYPE_PTS; 595 tp = fp->f_data; 596 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp); 597 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 = 598 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */ 599 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path)); 600 return (0); 601 } 602 603 static struct fileops ptsdev_ops = { 604 .fo_read = ptsdev_read, 605 .fo_write = ptsdev_write, 606 .fo_truncate = invfo_truncate, 607 .fo_ioctl = ptsdev_ioctl, 608 .fo_poll = ptsdev_poll, 609 .fo_kqfilter = ptsdev_kqfilter, 610 .fo_stat = ptsdev_stat, 611 .fo_close = ptsdev_close, 612 .fo_chmod = invfo_chmod, 613 .fo_chown = invfo_chown, 614 .fo_sendfile = invfo_sendfile, 615 .fo_fill_kinfo = ptsdev_fill_kinfo, 616 .fo_flags = DFLAG_PASSABLE, 617 }; 618 619 /* 620 * Driver-side hooks. 621 */ 622 623 static void 624 ptsdrv_outwakeup(struct tty *tp) 625 { 626 struct pts_softc *psc = tty_softc(tp); 627 628 cv_broadcast(&psc->pts_outwait); 629 selwakeup(&psc->pts_outpoll); 630 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0); 631 } 632 633 static void 634 ptsdrv_inwakeup(struct tty *tp) 635 { 636 struct pts_softc *psc = tty_softc(tp); 637 638 cv_broadcast(&psc->pts_inwait); 639 selwakeup(&psc->pts_inpoll); 640 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0); 641 } 642 643 static int 644 ptsdrv_open(struct tty *tp) 645 { 646 struct pts_softc *psc = tty_softc(tp); 647 648 psc->pts_flags &= ~PTS_FINISHED; 649 650 return (0); 651 } 652 653 static void 654 ptsdrv_close(struct tty *tp) 655 { 656 struct pts_softc *psc = tty_softc(tp); 657 658 /* Wake up any blocked readers/writers. */ 659 psc->pts_flags |= PTS_FINISHED; 660 ptsdrv_outwakeup(tp); 661 ptsdrv_inwakeup(tp); 662 } 663 664 static void 665 ptsdrv_pktnotify(struct tty *tp, char event) 666 { 667 struct pts_softc *psc = tty_softc(tp); 668 669 /* 670 * Clear conflicting flags. 671 */ 672 673 switch (event) { 674 case TIOCPKT_STOP: 675 psc->pts_pkt &= ~TIOCPKT_START; 676 break; 677 case TIOCPKT_START: 678 psc->pts_pkt &= ~TIOCPKT_STOP; 679 break; 680 case TIOCPKT_NOSTOP: 681 psc->pts_pkt &= ~TIOCPKT_DOSTOP; 682 break; 683 case TIOCPKT_DOSTOP: 684 psc->pts_pkt &= ~TIOCPKT_NOSTOP; 685 break; 686 } 687 688 psc->pts_pkt |= event; 689 ptsdrv_outwakeup(tp); 690 } 691 692 static void 693 ptsdrv_free(void *softc) 694 { 695 struct pts_softc *psc = softc; 696 697 /* Make device number available again. */ 698 if (psc->pts_unit >= 0) 699 free_unr(pts_pool, psc->pts_unit); 700 701 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0); 702 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1); 703 crfree(psc->pts_cred); 704 705 seldrain(&psc->pts_inpoll); 706 seldrain(&psc->pts_outpoll); 707 knlist_destroy(&psc->pts_inpoll.si_note); 708 knlist_destroy(&psc->pts_outpoll.si_note); 709 710 #ifdef PTS_EXTERNAL 711 /* Destroy master device as well. */ 712 if (psc->pts_cdev != NULL) 713 destroy_dev_sched(psc->pts_cdev); 714 #endif /* PTS_EXTERNAL */ 715 716 free(psc, M_PTS); 717 } 718 719 static struct ttydevsw pts_class = { 720 .tsw_flags = TF_NOPREFIX, 721 .tsw_outwakeup = ptsdrv_outwakeup, 722 .tsw_inwakeup = ptsdrv_inwakeup, 723 .tsw_open = ptsdrv_open, 724 .tsw_close = ptsdrv_close, 725 .tsw_pktnotify = ptsdrv_pktnotify, 726 .tsw_free = ptsdrv_free, 727 }; 728 729 #ifndef PTS_EXTERNAL 730 static 731 #endif /* !PTS_EXTERNAL */ 732 int 733 pts_alloc(int fflags, struct thread *td, struct file *fp) 734 { 735 int unit, ok, error; 736 struct tty *tp; 737 struct pts_softc *psc; 738 struct proc *p = td->td_proc; 739 struct ucred *cred = td->td_ucred; 740 741 /* Resource limiting. */ 742 PROC_LOCK(p); 743 error = racct_add(p, RACCT_NPTS, 1); 744 if (error != 0) { 745 PROC_UNLOCK(p); 746 return (EAGAIN); 747 } 748 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 749 if (!ok) { 750 racct_sub(p, RACCT_NPTS, 1); 751 PROC_UNLOCK(p); 752 return (EAGAIN); 753 } 754 PROC_UNLOCK(p); 755 756 /* Try to allocate a new pts unit number. */ 757 unit = alloc_unr(pts_pool); 758 if (unit < 0) { 759 racct_sub(p, RACCT_NPTS, 1); 760 chgptscnt(cred->cr_ruidinfo, -1, 0); 761 return (EAGAIN); 762 } 763 764 /* Allocate TTY and softc. */ 765 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 766 cv_init(&psc->pts_inwait, "ptsin"); 767 cv_init(&psc->pts_outwait, "ptsout"); 768 769 psc->pts_unit = unit; 770 psc->pts_cred = crhold(cred); 771 772 tp = tty_alloc(&pts_class, psc); 773 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 774 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 775 776 /* Expose the slave device as well. */ 777 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit); 778 779 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 780 781 return (0); 782 } 783 784 #ifdef PTS_EXTERNAL 785 int 786 pts_alloc_external(int fflags, struct thread *td, struct file *fp, 787 struct cdev *dev, const char *name) 788 { 789 int ok, error; 790 struct tty *tp; 791 struct pts_softc *psc; 792 struct proc *p = td->td_proc; 793 struct ucred *cred = td->td_ucred; 794 795 /* Resource limiting. */ 796 PROC_LOCK(p); 797 error = racct_add(p, RACCT_NPTS, 1); 798 if (error != 0) { 799 PROC_UNLOCK(p); 800 return (EAGAIN); 801 } 802 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 803 if (!ok) { 804 racct_sub(p, RACCT_NPTS, 1); 805 PROC_UNLOCK(p); 806 return (EAGAIN); 807 } 808 PROC_UNLOCK(p); 809 810 /* Allocate TTY and softc. */ 811 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 812 cv_init(&psc->pts_inwait, "ptsin"); 813 cv_init(&psc->pts_outwait, "ptsout"); 814 815 psc->pts_unit = -1; 816 psc->pts_cdev = dev; 817 psc->pts_cred = crhold(cred); 818 819 tp = tty_alloc(&pts_class, psc); 820 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 821 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 822 823 /* Expose the slave device as well. */ 824 tty_makedev(tp, td->td_ucred, "%s", name); 825 826 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 827 828 return (0); 829 } 830 #endif /* PTS_EXTERNAL */ 831 832 int 833 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap) 834 { 835 int error, fd; 836 struct file *fp; 837 838 /* 839 * POSIX states it's unspecified when other flags are passed. We 840 * don't allow this. 841 */ 842 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC)) 843 return (EINVAL); 844 845 error = falloc(td, &fp, &fd, uap->flags); 846 if (error) 847 return (error); 848 849 /* Allocate the actual pseudo-TTY. */ 850 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp); 851 if (error != 0) { 852 fdclose(td, fp, fd); 853 fdrop(fp, td); 854 return (error); 855 } 856 857 /* Pass it back to userspace. */ 858 td->td_retval[0] = fd; 859 fdrop(fp, td); 860 861 return (0); 862 } 863 864 static void 865 pts_init(void *unused) 866 { 867 868 pts_pool = new_unrhdr(0, INT_MAX, NULL); 869 } 870 871 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL); 872