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: stable/11/sys/kern/tty_pts.c 356020 2019-12-22 19:06:45Z kevans $"); 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/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/sysent.h> 62#include <sys/sysproto.h> 63#include <sys/systm.h> 64#include <sys/tty.h> 65#include <sys/ttycom.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 */ 76static struct unrhdr *pts_pool; 77 78static 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 */ 87struct 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 110static int 111ptsdev_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 184static int 185ptsdev_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 246done: 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 257static int 258ptsdev_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 if (psc->pts_flags & PTS_FINISHED) { 275 /* Force read() to be called. */ 276 *(int *)data = 1; 277 } else { 278 *(int *)data = ttydisc_getc_poll(tp); 279 } 280 tty_unlock(tp); 281 return (0); 282 case FIODGNAME: { 283 struct fiodgname_arg *fgn; 284 const char *p; 285 int i; 286 287 /* Reverse device name lookups, for ptsname() and ttyname(). */ 288 fgn = data; 289 p = tty_devname(tp); 290 i = strlen(p) + 1; 291 if (i > fgn->len) 292 return (EINVAL); 293 return copyout(p, fgn->buf, i); 294 } 295 296 /* 297 * We need to implement TIOCGPGRP and TIOCGSID here again. When 298 * called on the pseudo-terminal master, it should not check if 299 * the terminal is the foreground terminal of the calling 300 * process. 301 * 302 * TIOCGETA is also implemented here. Various Linux PTY routines 303 * often call isatty(), which is implemented by tcgetattr(). 304 */ 305#ifdef PTS_LINUX 306 case TIOCGETA: 307 /* Obtain terminal flags through tcgetattr(). */ 308 tty_lock(tp); 309 *(struct termios*)data = tp->t_termios; 310 tty_unlock(tp); 311 return (0); 312#endif /* PTS_LINUX */ 313 case TIOCSETAF: 314 case TIOCSETAW: 315 /* 316 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and 317 * TCSADRAIN into something different. If an application would 318 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may 319 * deadlock waiting for all data to be read. 320 */ 321 cmd = TIOCSETA; 322 break; 323#if defined(PTS_COMPAT) || defined(PTS_LINUX) 324 case TIOCGPTN: 325 /* 326 * Get the device unit number. 327 */ 328 if (psc->pts_unit < 0) 329 return (ENOTTY); 330 *(unsigned int *)data = psc->pts_unit; 331 return (0); 332#endif /* PTS_COMPAT || PTS_LINUX */ 333 case TIOCGPGRP: 334 /* Get the foreground process group ID. */ 335 tty_lock(tp); 336 if (tp->t_pgrp != NULL) 337 *(int *)data = tp->t_pgrp->pg_id; 338 else 339 *(int *)data = NO_PID; 340 tty_unlock(tp); 341 return (0); 342 case TIOCGSID: 343 /* Get the session leader process ID. */ 344 tty_lock(tp); 345 if (tp->t_session == NULL) 346 error = ENOTTY; 347 else 348 *(int *)data = tp->t_session->s_sid; 349 tty_unlock(tp); 350 return (error); 351 case TIOCPTMASTER: 352 /* Yes, we are a pseudo-terminal master. */ 353 return (0); 354 case TIOCSIG: 355 /* Signal the foreground process group. */ 356 sig = *(int *)data; 357 if (sig < 1 || sig >= NSIG) 358 return (EINVAL); 359 360 tty_lock(tp); 361 tty_signal_pgrp(tp, sig); 362 tty_unlock(tp); 363 return (0); 364 case TIOCPKT: 365 /* Enable/disable packet mode. */ 366 tty_lock(tp); 367 if (*(int *)data) 368 psc->pts_flags |= PTS_PKT; 369 else 370 psc->pts_flags &= ~PTS_PKT; 371 tty_unlock(tp); 372 return (0); 373 } 374 375 /* Just redirect this ioctl to the slave device. */ 376 tty_lock(tp); 377 error = tty_ioctl(tp, cmd, data, fp->f_flag, td); 378 tty_unlock(tp); 379 if (error == ENOIOCTL) 380 error = ENOTTY; 381 382 return (error); 383} 384 385static int 386ptsdev_poll(struct file *fp, int events, struct ucred *active_cred, 387 struct thread *td) 388{ 389 struct tty *tp = fp->f_data; 390 struct pts_softc *psc = tty_softc(tp); 391 int revents = 0; 392 393 tty_lock(tp); 394 395 if (psc->pts_flags & PTS_FINISHED) { 396 /* Slave device is not opened. */ 397 tty_unlock(tp); 398 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP); 399 } 400 401 if (events & (POLLIN|POLLRDNORM)) { 402 /* See if we can getc something. */ 403 if (ttydisc_getc_poll(tp) || 404 (psc->pts_flags & PTS_PKT && psc->pts_pkt)) 405 revents |= events & (POLLIN|POLLRDNORM); 406 } 407 if (events & (POLLOUT|POLLWRNORM)) { 408 /* See if we can rint something. */ 409 if (ttydisc_rint_poll(tp)) 410 revents |= events & (POLLOUT|POLLWRNORM); 411 } 412 413 /* 414 * No need to check for POLLHUP here. This device cannot be used 415 * as a callout device, which means we always have a carrier, 416 * because the master is. 417 */ 418 419 if (revents == 0) { 420 /* 421 * This code might look misleading, but the naming of 422 * poll events on this side is the opposite of the slave 423 * device. 424 */ 425 if (events & (POLLIN|POLLRDNORM)) 426 selrecord(td, &psc->pts_outpoll); 427 if (events & (POLLOUT|POLLWRNORM)) 428 selrecord(td, &psc->pts_inpoll); 429 } 430 431 tty_unlock(tp); 432 433 return (revents); 434} 435 436/* 437 * kqueue support. 438 */ 439 440static void 441pts_kqops_read_detach(struct knote *kn) 442{ 443 struct file *fp = kn->kn_fp; 444 struct tty *tp = fp->f_data; 445 struct pts_softc *psc = tty_softc(tp); 446 447 knlist_remove(&psc->pts_outpoll.si_note, kn, 0); 448} 449 450static int 451pts_kqops_read_event(struct knote *kn, long hint) 452{ 453 struct file *fp = kn->kn_fp; 454 struct tty *tp = fp->f_data; 455 struct pts_softc *psc = tty_softc(tp); 456 457 if (psc->pts_flags & PTS_FINISHED) { 458 kn->kn_flags |= EV_EOF; 459 return (1); 460 } else { 461 kn->kn_data = ttydisc_getc_poll(tp); 462 return (kn->kn_data > 0); 463 } 464} 465 466static void 467pts_kqops_write_detach(struct knote *kn) 468{ 469 struct file *fp = kn->kn_fp; 470 struct tty *tp = fp->f_data; 471 struct pts_softc *psc = tty_softc(tp); 472 473 knlist_remove(&psc->pts_inpoll.si_note, kn, 0); 474} 475 476static int 477pts_kqops_write_event(struct knote *kn, long hint) 478{ 479 struct file *fp = kn->kn_fp; 480 struct tty *tp = fp->f_data; 481 struct pts_softc *psc = tty_softc(tp); 482 483 if (psc->pts_flags & PTS_FINISHED) { 484 kn->kn_flags |= EV_EOF; 485 return (1); 486 } else { 487 kn->kn_data = ttydisc_rint_poll(tp); 488 return (kn->kn_data > 0); 489 } 490} 491 492static struct filterops pts_kqops_read = { 493 .f_isfd = 1, 494 .f_detach = pts_kqops_read_detach, 495 .f_event = pts_kqops_read_event, 496}; 497static struct filterops pts_kqops_write = { 498 .f_isfd = 1, 499 .f_detach = pts_kqops_write_detach, 500 .f_event = pts_kqops_write_event, 501}; 502 503static int 504ptsdev_kqfilter(struct file *fp, struct knote *kn) 505{ 506 struct tty *tp = fp->f_data; 507 struct pts_softc *psc = tty_softc(tp); 508 int error = 0; 509 510 tty_lock(tp); 511 512 switch (kn->kn_filter) { 513 case EVFILT_READ: 514 kn->kn_fop = &pts_kqops_read; 515 knlist_add(&psc->pts_outpoll.si_note, kn, 1); 516 break; 517 case EVFILT_WRITE: 518 kn->kn_fop = &pts_kqops_write; 519 knlist_add(&psc->pts_inpoll.si_note, kn, 1); 520 break; 521 default: 522 error = EINVAL; 523 break; 524 } 525 526 tty_unlock(tp); 527 return (error); 528} 529 530static int 531ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 532 struct thread *td) 533{ 534 struct tty *tp = fp->f_data; 535#ifdef PTS_EXTERNAL 536 struct pts_softc *psc = tty_softc(tp); 537#endif /* PTS_EXTERNAL */ 538 struct cdev *dev = tp->t_dev; 539 540 /* 541 * According to POSIX, we must implement an fstat(). This also 542 * makes this implementation compatible with Linux binaries, 543 * because Linux calls fstat() on the pseudo-terminal master to 544 * obtain st_rdev. 545 * 546 * XXX: POSIX also mentions we must fill in st_dev, but how? 547 */ 548 549 bzero(sb, sizeof *sb); 550#ifdef PTS_EXTERNAL 551 if (psc->pts_cdev != NULL) 552 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev); 553 else 554#endif /* PTS_EXTERNAL */ 555 sb->st_ino = sb->st_rdev = tty_udev(tp); 556 557 sb->st_atim = dev->si_atime; 558 sb->st_ctim = dev->si_ctime; 559 sb->st_mtim = dev->si_mtime; 560 sb->st_uid = dev->si_uid; 561 sb->st_gid = dev->si_gid; 562 sb->st_mode = dev->si_mode | S_IFCHR; 563 564 return (0); 565} 566 567static int 568ptsdev_close(struct file *fp, struct thread *td) 569{ 570 struct tty *tp = fp->f_data; 571 572 /* Deallocate TTY device. */ 573 tty_lock(tp); 574 tty_rel_gone(tp); 575 576 /* 577 * Open of /dev/ptmx or /dev/ptyXX changes the type of file 578 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode 579 * use count, we need to decrement it, and possibly do other 580 * required cleanup. 581 */ 582 if (fp->f_vnode != NULL) 583 return (vnops.fo_close(fp, td)); 584 585 return (0); 586} 587 588static int 589ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 590{ 591 struct tty *tp; 592 593 kif->kf_type = KF_TYPE_PTS; 594 tp = fp->f_data; 595 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp); 596 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path)); 597 return (0); 598} 599 600static 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_flags = DFLAG_PASSABLE, 614}; 615 616/* 617 * Driver-side hooks. 618 */ 619 620static void 621ptsdrv_outwakeup(struct tty *tp) 622{ 623 struct pts_softc *psc = tty_softc(tp); 624 625 cv_broadcast(&psc->pts_outwait); 626 selwakeup(&psc->pts_outpoll); 627 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0); 628} 629 630static void 631ptsdrv_inwakeup(struct tty *tp) 632{ 633 struct pts_softc *psc = tty_softc(tp); 634 635 cv_broadcast(&psc->pts_inwait); 636 selwakeup(&psc->pts_inpoll); 637 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0); 638} 639 640static int 641ptsdrv_open(struct tty *tp) 642{ 643 struct pts_softc *psc = tty_softc(tp); 644 645 psc->pts_flags &= ~PTS_FINISHED; 646 647 return (0); 648} 649 650static void 651ptsdrv_close(struct tty *tp) 652{ 653 struct pts_softc *psc = tty_softc(tp); 654 655 /* Wake up any blocked readers/writers. */ 656 psc->pts_flags |= PTS_FINISHED; 657 ptsdrv_outwakeup(tp); 658 ptsdrv_inwakeup(tp); 659} 660 661static void 662ptsdrv_pktnotify(struct tty *tp, char event) 663{ 664 struct pts_softc *psc = tty_softc(tp); 665 666 /* 667 * Clear conflicting flags. 668 */ 669 670 switch (event) { 671 case TIOCPKT_STOP: 672 psc->pts_pkt &= ~TIOCPKT_START; 673 break; 674 case TIOCPKT_START: 675 psc->pts_pkt &= ~TIOCPKT_STOP; 676 break; 677 case TIOCPKT_NOSTOP: 678 psc->pts_pkt &= ~TIOCPKT_DOSTOP; 679 break; 680 case TIOCPKT_DOSTOP: 681 psc->pts_pkt &= ~TIOCPKT_NOSTOP; 682 break; 683 } 684 685 psc->pts_pkt |= event; 686 ptsdrv_outwakeup(tp); 687} 688 689static void 690ptsdrv_free(void *softc) 691{ 692 struct pts_softc *psc = softc; 693 694 /* Make device number available again. */ 695 if (psc->pts_unit >= 0) 696 free_unr(pts_pool, psc->pts_unit); 697 698 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0); 699 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1); 700 crfree(psc->pts_cred); 701 702 seldrain(&psc->pts_inpoll); 703 seldrain(&psc->pts_outpoll); 704 knlist_destroy(&psc->pts_inpoll.si_note); 705 knlist_destroy(&psc->pts_outpoll.si_note); 706 707#ifdef PTS_EXTERNAL 708 /* Destroy master device as well. */ 709 if (psc->pts_cdev != NULL) 710 destroy_dev_sched(psc->pts_cdev); 711#endif /* PTS_EXTERNAL */ 712 713 free(psc, M_PTS); 714} 715 716static struct ttydevsw pts_class = { 717 .tsw_flags = TF_NOPREFIX, 718 .tsw_outwakeup = ptsdrv_outwakeup, 719 .tsw_inwakeup = ptsdrv_inwakeup, 720 .tsw_open = ptsdrv_open, 721 .tsw_close = ptsdrv_close, 722 .tsw_pktnotify = ptsdrv_pktnotify, 723 .tsw_free = ptsdrv_free, 724}; 725 726#ifndef PTS_EXTERNAL 727static 728#endif /* !PTS_EXTERNAL */ 729int 730pts_alloc(int fflags, struct thread *td, struct file *fp) 731{ 732 int unit, ok, error; 733 struct tty *tp; 734 struct pts_softc *psc; 735 struct proc *p = td->td_proc; 736 struct ucred *cred = td->td_ucred; 737 738 /* Resource limiting. */ 739 PROC_LOCK(p); 740 error = racct_add(p, RACCT_NPTS, 1); 741 if (error != 0) { 742 PROC_UNLOCK(p); 743 return (EAGAIN); 744 } 745 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 746 if (!ok) { 747 racct_sub(p, RACCT_NPTS, 1); 748 PROC_UNLOCK(p); 749 return (EAGAIN); 750 } 751 PROC_UNLOCK(p); 752 753 /* Try to allocate a new pts unit number. */ 754 unit = alloc_unr(pts_pool); 755 if (unit < 0) { 756 racct_sub(p, RACCT_NPTS, 1); 757 chgptscnt(cred->cr_ruidinfo, -1, 0); 758 return (EAGAIN); 759 } 760 761 /* Allocate TTY and softc. */ 762 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 763 cv_init(&psc->pts_inwait, "ptsin"); 764 cv_init(&psc->pts_outwait, "ptsout"); 765 766 psc->pts_unit = unit; 767 psc->pts_cred = crhold(cred); 768 769 tp = tty_alloc(&pts_class, psc); 770 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 771 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 772 773 /* Expose the slave device as well. */ 774 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit); 775 776 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 777 778 return (0); 779} 780 781#ifdef PTS_EXTERNAL 782int 783pts_alloc_external(int fflags, struct thread *td, struct file *fp, 784 struct cdev *dev, const char *name) 785{ 786 int ok, error; 787 struct tty *tp; 788 struct pts_softc *psc; 789 struct proc *p = td->td_proc; 790 struct ucred *cred = td->td_ucred; 791 792 /* Resource limiting. */ 793 PROC_LOCK(p); 794 error = racct_add(p, RACCT_NPTS, 1); 795 if (error != 0) { 796 PROC_UNLOCK(p); 797 return (EAGAIN); 798 } 799 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 800 if (!ok) { 801 racct_sub(p, RACCT_NPTS, 1); 802 PROC_UNLOCK(p); 803 return (EAGAIN); 804 } 805 PROC_UNLOCK(p); 806 807 /* Allocate TTY and softc. */ 808 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 809 cv_init(&psc->pts_inwait, "ptsin"); 810 cv_init(&psc->pts_outwait, "ptsout"); 811 812 psc->pts_unit = -1; 813 psc->pts_cdev = dev; 814 psc->pts_cred = crhold(cred); 815 816 tp = tty_alloc(&pts_class, psc); 817 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 818 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 819 820 /* Expose the slave device as well. */ 821 tty_makedev(tp, td->td_ucred, "%s", name); 822 823 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 824 825 return (0); 826} 827#endif /* PTS_EXTERNAL */ 828 829int 830sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap) 831{ 832 int error, fd; 833 struct file *fp; 834 835 /* 836 * POSIX states it's unspecified when other flags are passed. We 837 * don't allow this. 838 */ 839 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC)) 840 return (EINVAL); 841 842 error = falloc(td, &fp, &fd, uap->flags); 843 if (error) 844 return (error); 845 846 /* Allocate the actual pseudo-TTY. */ 847 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp); 848 if (error != 0) { 849 fdclose(td, fp, fd); 850 fdrop(fp, td); 851 return (error); 852 } 853 854 /* Pass it back to userspace. */ 855 td->td_retval[0] = fd; 856 fdrop(fp, td); 857 858 return (0); 859} 860 861static void 862pts_init(void *unused) 863{ 864 865 pts_pool = new_unrhdr(0, INT_MAX, NULL); 866} 867 868SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL); 869