1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 /* 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/mutex.h> 52 #include <sys/poll.h> 53 #include <sys/proc.h> 54 #include <sys/racct.h> 55 #include <sys/resourcevar.h> 56 #include <sys/serial.h> 57 #include <sys/stat.h> 58 #include <sys/syscall.h> 59 #include <sys/syscallsubr.h> 60 #include <sys/sysctl.h> 61 #include <sys/sysproto.h> 62 #include <sys/systm.h> 63 #include <sys/tty.h> 64 #include <sys/ttycom.h> 65 #include <sys/uio.h> 66 #include <sys/user.h> 67 68 #include <machine/stdarg.h> 69 70 /* 71 * Our utmp(5) format is limited to 8-byte TTY line names. This means 72 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow 73 * users to increase this number, assuming they have manually increased 74 * UT_LINESIZE. 75 */ 76 static struct unrhdr *pts_pool; 77 78 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device"); 79 80 /* 81 * Per-PTS structure. 82 * 83 * List of locks 84 * (t) locked by tty_lock() 85 * (c) const until freeing 86 */ 87 struct pts_softc { 88 int pts_unit; /* (c) Device unit number. */ 89 unsigned int pts_flags; /* (t) Device flags. */ 90 #define PTS_PKT 0x1 /* Packet mode. */ 91 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */ 92 char pts_pkt; /* (t) Unread packet mode data. */ 93 94 struct cv pts_inwait; /* (t) Blocking write() on master. */ 95 struct selinfo pts_inpoll; /* (t) Select queue for write(). */ 96 struct cv pts_outwait; /* (t) Blocking read() on master. */ 97 struct selinfo pts_outpoll; /* (t) Select queue for read(). */ 98 99 #ifdef PTS_EXTERNAL 100 struct cdev *pts_cdev; /* (c) Master device node. */ 101 #endif /* PTS_EXTERNAL */ 102 103 struct ucred *pts_cred; /* (c) Resource limit. */ 104 }; 105 106 /* 107 * Controller-side file operations. 108 */ 109 110 static int 111 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 112 int flags, struct thread *td) 113 { 114 struct tty *tp = fp->f_data; 115 struct pts_softc *psc = tty_softc(tp); 116 int error = 0; 117 char pkt; 118 119 if (uio->uio_resid == 0) 120 return (0); 121 122 tty_lock(tp); 123 124 for (;;) { 125 /* 126 * Implement packet mode. When packet mode is turned on, 127 * the first byte contains a bitmask of events that 128 * occurred (start, stop, flush, window size, etc). 129 */ 130 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) { 131 pkt = psc->pts_pkt; 132 psc->pts_pkt = 0; 133 tty_unlock(tp); 134 135 error = ureadc(pkt, uio); 136 return (error); 137 } 138 139 /* 140 * Transmit regular data. 141 * 142 * XXX: We shouldn't use ttydisc_getc_poll()! Even 143 * though in this implementation, there is likely going 144 * to be data, we should just call ttydisc_getc_uio() 145 * and use its return value to sleep. 146 */ 147 if (ttydisc_getc_poll(tp)) { 148 if (psc->pts_flags & PTS_PKT) { 149 /* 150 * XXX: Small race. Fortunately PTY 151 * consumers aren't multithreaded. 152 */ 153 154 tty_unlock(tp); 155 error = ureadc(TIOCPKT_DATA, uio); 156 if (error) 157 return (error); 158 tty_lock(tp); 159 } 160 161 error = ttydisc_getc_uio(tp, uio); 162 break; 163 } 164 165 /* Maybe the device isn't used anyway. */ 166 if (psc->pts_flags & PTS_FINISHED) 167 break; 168 169 /* Wait for more data. */ 170 if (fp->f_flag & O_NONBLOCK) { 171 error = EWOULDBLOCK; 172 break; 173 } 174 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx); 175 if (error != 0) 176 break; 177 } 178 179 tty_unlock(tp); 180 181 return (error); 182 } 183 184 static int 185 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 186 int flags, struct thread *td) 187 { 188 struct tty *tp = fp->f_data; 189 struct pts_softc *psc = tty_softc(tp); 190 char ib[256], *ibstart; 191 size_t iblen, rintlen; 192 int error = 0; 193 194 if (uio->uio_resid == 0) 195 return (0); 196 197 for (;;) { 198 ibstart = ib; 199 iblen = MIN(uio->uio_resid, sizeof ib); 200 error = uiomove(ib, iblen, uio); 201 202 tty_lock(tp); 203 if (error != 0) { 204 iblen = 0; 205 goto done; 206 } 207 208 /* 209 * When possible, avoid the slow path. rint_bypass() 210 * copies all input to the input queue at once. 211 */ 212 MPASS(iblen > 0); 213 do { 214 rintlen = ttydisc_rint_simple(tp, ibstart, iblen); 215 ibstart += rintlen; 216 iblen -= rintlen; 217 if (iblen == 0) { 218 /* All data written. */ 219 break; 220 } 221 222 /* Maybe the device isn't used anyway. */ 223 if (psc->pts_flags & PTS_FINISHED) { 224 error = EIO; 225 goto done; 226 } 227 228 /* Wait for more data. */ 229 if (fp->f_flag & O_NONBLOCK) { 230 error = EWOULDBLOCK; 231 goto done; 232 } 233 234 /* Wake up users on the slave side. */ 235 ttydisc_rint_done(tp); 236 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx); 237 if (error != 0) 238 goto done; 239 } while (iblen > 0); 240 241 if (uio->uio_resid == 0) 242 break; 243 tty_unlock(tp); 244 } 245 246 done: ttydisc_rint_done(tp); 247 tty_unlock(tp); 248 249 /* 250 * Don't account for the part of the buffer that we couldn't 251 * pass to the TTY. 252 */ 253 uio->uio_resid += iblen; 254 return (error); 255 } 256 257 static int 258 ptsdev_ioctl(struct file *fp, u_long cmd, void *data, 259 struct ucred *active_cred, struct thread *td) 260 { 261 struct tty *tp = fp->f_data; 262 struct pts_softc *psc = tty_softc(tp); 263 int error = 0, sig; 264 265 switch (cmd) { 266 case FIODTYPE: 267 *(int *)data = D_TTY; 268 return (0); 269 case FIONBIO: 270 /* This device supports non-blocking operation. */ 271 return (0); 272 case FIONREAD: 273 tty_lock(tp); 274 *(int *)data = ttydisc_getc_poll(tp); 275 tty_unlock(tp); 276 return (0); 277 case FIODGNAME: 278 #ifdef COMPAT_FREEBSD32 279 case FIODGNAME_32: 280 #endif 281 { 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, fiodgname_buf_get_ptr(fgn, cmd), 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 { 532 struct tty *tp = fp->f_data; 533 #ifdef PTS_EXTERNAL 534 struct pts_softc *psc = tty_softc(tp); 535 #endif /* PTS_EXTERNAL */ 536 struct cdev *dev = tp->t_dev; 537 538 /* 539 * According to POSIX, we must implement an fstat(). This also 540 * makes this implementation compatible with Linux binaries, 541 * because Linux calls fstat() on the pseudo-terminal master to 542 * obtain st_rdev. 543 * 544 * XXX: POSIX also mentions we must fill in st_dev, but how? 545 */ 546 547 bzero(sb, sizeof *sb); 548 #ifdef PTS_EXTERNAL 549 if (psc->pts_cdev != NULL) 550 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev); 551 else 552 #endif /* PTS_EXTERNAL */ 553 sb->st_ino = sb->st_rdev = tty_udev(tp); 554 555 sb->st_atim = dev->si_atime; 556 sb->st_ctim = dev->si_ctime; 557 sb->st_mtim = dev->si_mtime; 558 sb->st_uid = dev->si_uid; 559 sb->st_gid = dev->si_gid; 560 sb->st_mode = dev->si_mode | S_IFCHR; 561 562 return (0); 563 } 564 565 static int 566 ptsdev_close(struct file *fp, struct thread *td) 567 { 568 struct tty *tp = fp->f_data; 569 570 /* Deallocate TTY device. */ 571 tty_lock(tp); 572 tty_rel_gone(tp); 573 574 /* 575 * Open of /dev/ptmx or /dev/ptyXX changes the type of file 576 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode 577 * use count, we need to decrement it, and possibly do other 578 * required cleanup. 579 */ 580 if (fp->f_vnode != NULL) 581 return (vnops.fo_close(fp, td)); 582 583 return (0); 584 } 585 586 static int 587 ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 588 { 589 struct tty *tp; 590 591 kif->kf_type = KF_TYPE_PTS; 592 tp = fp->f_data; 593 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp); 594 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 = 595 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */ 596 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path)); 597 return (0); 598 } 599 600 static struct fileops ptsdev_ops = { 601 .fo_read = ptsdev_read, 602 .fo_write = ptsdev_write, 603 .fo_truncate = invfo_truncate, 604 .fo_ioctl = ptsdev_ioctl, 605 .fo_poll = ptsdev_poll, 606 .fo_kqfilter = ptsdev_kqfilter, 607 .fo_stat = ptsdev_stat, 608 .fo_close = ptsdev_close, 609 .fo_chmod = invfo_chmod, 610 .fo_chown = invfo_chown, 611 .fo_sendfile = invfo_sendfile, 612 .fo_fill_kinfo = ptsdev_fill_kinfo, 613 .fo_cmp = file_kcmp_generic, 614 .fo_flags = DFLAG_PASSABLE, 615 }; 616 617 /* 618 * Driver-side hooks. 619 */ 620 621 static void 622 ptsdrv_outwakeup(struct tty *tp) 623 { 624 struct pts_softc *psc = tty_softc(tp); 625 626 cv_broadcast(&psc->pts_outwait); 627 selwakeup(&psc->pts_outpoll); 628 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0); 629 } 630 631 static void 632 ptsdrv_inwakeup(struct tty *tp) 633 { 634 struct pts_softc *psc = tty_softc(tp); 635 636 cv_broadcast(&psc->pts_inwait); 637 selwakeup(&psc->pts_inpoll); 638 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0); 639 } 640 641 static int 642 ptsdrv_open(struct tty *tp) 643 { 644 struct pts_softc *psc = tty_softc(tp); 645 646 psc->pts_flags &= ~PTS_FINISHED; 647 648 return (0); 649 } 650 651 static void 652 ptsdrv_close(struct tty *tp) 653 { 654 struct pts_softc *psc = tty_softc(tp); 655 656 /* Wake up any blocked readers/writers. */ 657 psc->pts_flags |= PTS_FINISHED; 658 ptsdrv_outwakeup(tp); 659 ptsdrv_inwakeup(tp); 660 } 661 662 static void 663 ptsdrv_pktnotify(struct tty *tp, char event) 664 { 665 struct pts_softc *psc = tty_softc(tp); 666 667 /* 668 * Clear conflicting flags. 669 */ 670 671 switch (event) { 672 case TIOCPKT_STOP: 673 psc->pts_pkt &= ~TIOCPKT_START; 674 break; 675 case TIOCPKT_START: 676 psc->pts_pkt &= ~TIOCPKT_STOP; 677 break; 678 case TIOCPKT_NOSTOP: 679 psc->pts_pkt &= ~TIOCPKT_DOSTOP; 680 break; 681 case TIOCPKT_DOSTOP: 682 psc->pts_pkt &= ~TIOCPKT_NOSTOP; 683 break; 684 } 685 686 psc->pts_pkt |= event; 687 ptsdrv_outwakeup(tp); 688 } 689 690 static void 691 ptsdrv_free(void *softc) 692 { 693 struct pts_softc *psc = softc; 694 695 /* Make device number available again. */ 696 if (psc->pts_unit >= 0) 697 free_unr(pts_pool, psc->pts_unit); 698 699 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0); 700 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1); 701 crfree(psc->pts_cred); 702 703 seldrain(&psc->pts_inpoll); 704 seldrain(&psc->pts_outpoll); 705 knlist_destroy(&psc->pts_inpoll.si_note); 706 knlist_destroy(&psc->pts_outpoll.si_note); 707 708 #ifdef PTS_EXTERNAL 709 /* Destroy master device as well. */ 710 if (psc->pts_cdev != NULL) 711 destroy_dev_sched(psc->pts_cdev); 712 #endif /* PTS_EXTERNAL */ 713 714 free(psc, M_PTS); 715 } 716 717 static struct ttydevsw pts_class = { 718 .tsw_flags = TF_NOPREFIX, 719 .tsw_outwakeup = ptsdrv_outwakeup, 720 .tsw_inwakeup = ptsdrv_inwakeup, 721 .tsw_open = ptsdrv_open, 722 .tsw_close = ptsdrv_close, 723 .tsw_pktnotify = ptsdrv_pktnotify, 724 .tsw_free = ptsdrv_free, 725 }; 726 727 #ifndef PTS_EXTERNAL 728 static 729 #endif /* !PTS_EXTERNAL */ 730 int 731 pts_alloc(int fflags, struct thread *td, struct file *fp) 732 { 733 int unit, ok, error; 734 struct tty *tp; 735 struct pts_softc *psc; 736 struct proc *p = td->td_proc; 737 struct ucred *cred = td->td_ucred; 738 739 /* Resource limiting. */ 740 PROC_LOCK(p); 741 error = racct_add(p, RACCT_NPTS, 1); 742 if (error != 0) { 743 PROC_UNLOCK(p); 744 return (EAGAIN); 745 } 746 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 747 if (!ok) { 748 racct_sub(p, RACCT_NPTS, 1); 749 PROC_UNLOCK(p); 750 return (EAGAIN); 751 } 752 PROC_UNLOCK(p); 753 754 /* Try to allocate a new pts unit number. */ 755 unit = alloc_unr(pts_pool); 756 if (unit < 0) { 757 racct_sub(p, RACCT_NPTS, 1); 758 chgptscnt(cred->cr_ruidinfo, -1, 0); 759 return (EAGAIN); 760 } 761 762 /* Allocate TTY and softc. */ 763 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 764 cv_init(&psc->pts_inwait, "ptsin"); 765 cv_init(&psc->pts_outwait, "ptsout"); 766 767 psc->pts_unit = unit; 768 psc->pts_cred = crhold(cred); 769 770 tp = tty_alloc(&pts_class, psc); 771 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 772 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 773 774 /* Expose the slave device as well. */ 775 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit); 776 777 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 778 779 return (0); 780 } 781 782 #ifdef PTS_EXTERNAL 783 int 784 pts_alloc_external(int fflags, struct thread *td, struct file *fp, 785 struct cdev *dev, const char *name) 786 { 787 int ok, error; 788 struct tty *tp; 789 struct pts_softc *psc; 790 struct proc *p = td->td_proc; 791 struct ucred *cred = td->td_ucred; 792 793 /* Resource limiting. */ 794 PROC_LOCK(p); 795 error = racct_add(p, RACCT_NPTS, 1); 796 if (error != 0) { 797 PROC_UNLOCK(p); 798 return (EAGAIN); 799 } 800 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 801 if (!ok) { 802 racct_sub(p, RACCT_NPTS, 1); 803 PROC_UNLOCK(p); 804 return (EAGAIN); 805 } 806 PROC_UNLOCK(p); 807 808 /* Allocate TTY and softc. */ 809 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 810 cv_init(&psc->pts_inwait, "ptsin"); 811 cv_init(&psc->pts_outwait, "ptsout"); 812 813 psc->pts_unit = -1; 814 psc->pts_cdev = dev; 815 psc->pts_cred = crhold(cred); 816 817 tp = tty_alloc(&pts_class, psc); 818 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 819 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 820 821 /* Expose the slave device as well. */ 822 tty_makedev(tp, td->td_ucred, "%s", name); 823 824 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 825 826 return (0); 827 } 828 #endif /* PTS_EXTERNAL */ 829 830 int 831 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap) 832 { 833 int error, fd; 834 struct file *fp; 835 836 /* 837 * POSIX states it's unspecified when other flags are passed. We 838 * don't allow this. 839 */ 840 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC)) 841 return (EINVAL); 842 843 error = falloc(td, &fp, &fd, uap->flags); 844 if (error) 845 return (error); 846 847 /* Allocate the actual pseudo-TTY. */ 848 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp); 849 if (error != 0) { 850 fdclose(td, fp, fd); 851 fdrop(fp, td); 852 return (error); 853 } 854 855 /* Pass it back to userspace. */ 856 td->td_retval[0] = fd; 857 fdrop(fp, td); 858 859 return (0); 860 } 861 862 static void 863 pts_init(void *unused) 864 { 865 866 pts_pool = new_unrhdr(0, INT_MAX, NULL); 867 } 868 869 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL); 870