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/mutex.h> 54#include <sys/poll.h> 55#include <sys/proc.h> 56#include <sys/racct.h> 57#include <sys/resourcevar.h> 58#include <sys/serial.h> 59#include <sys/stat.h> 60#include <sys/syscall.h> 61#include <sys/syscallsubr.h> 62#include <sys/sysctl.h> 63#include <sys/sysent.h> 64#include <sys/sysproto.h> 65#include <sys/systm.h> 66#include <sys/tty.h> 67#include <sys/ttycom.h> 68#include <sys/uio.h> 69#include <sys/user.h> 70 71#include <machine/stdarg.h> 72 73/* 74 * Our utmp(5) format is limited to 8-byte TTY line names. This means 75 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow 76 * users to increase this number, assuming they have manually increased 77 * UT_LINESIZE. 78 */ 79static struct unrhdr *pts_pool; 80 81static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device"); 82 83/* 84 * Per-PTS structure. 85 * 86 * List of locks 87 * (t) locked by tty_lock() 88 * (c) const until freeing 89 */ 90struct pts_softc { 91 int pts_unit; /* (c) Device unit number. */ 92 unsigned int pts_flags; /* (t) Device flags. */ 93#define PTS_PKT 0x1 /* Packet mode. */ 94#define PTS_FINISHED 0x2 /* Return errors on read()/write(). */ 95 char pts_pkt; /* (t) Unread packet mode data. */ 96 97 struct cv pts_inwait; /* (t) Blocking write() on master. */ 98 struct selinfo pts_inpoll; /* (t) Select queue for write(). */ 99 struct cv pts_outwait; /* (t) Blocking read() on master. */ 100 struct selinfo pts_outpoll; /* (t) Select queue for read(). */ 101 102#ifdef PTS_EXTERNAL 103 struct cdev *pts_cdev; /* (c) Master device node. */ 104#endif /* PTS_EXTERNAL */ 105 106 struct ucred *pts_cred; /* (c) Resource limit. */ 107}; 108 109/* 110 * Controller-side file operations. 111 */ 112 113static int 114ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 115 int flags, struct thread *td) 116{ 117 struct tty *tp = fp->f_data; 118 struct pts_softc *psc = tty_softc(tp); 119 int error = 0; 120 char pkt; 121 122 if (uio->uio_resid == 0) 123 return (0); 124 125 tty_lock(tp); 126 127 for (;;) { 128 /* 129 * Implement packet mode. When packet mode is turned on, 130 * the first byte contains a bitmask of events that 131 * occurred (start, stop, flush, window size, etc). 132 */ 133 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) { 134 pkt = psc->pts_pkt; 135 psc->pts_pkt = 0; 136 tty_unlock(tp); 137 138 error = ureadc(pkt, uio); 139 return (error); 140 } 141 142 /* 143 * Transmit regular data. 144 * 145 * XXX: We shouldn't use ttydisc_getc_poll()! Even 146 * though in this implementation, there is likely going 147 * to be data, we should just call ttydisc_getc_uio() 148 * and use its return value to sleep. 149 */ 150 if (ttydisc_getc_poll(tp)) { 151 if (psc->pts_flags & PTS_PKT) { 152 /* 153 * XXX: Small race. Fortunately PTY 154 * consumers aren't multithreaded. 155 */ 156 157 tty_unlock(tp); 158 error = ureadc(TIOCPKT_DATA, uio); 159 if (error) 160 return (error); 161 tty_lock(tp); 162 } 163 164 error = ttydisc_getc_uio(tp, uio); 165 break; 166 } 167 168 /* Maybe the device isn't used anyway. */ 169 if (psc->pts_flags & PTS_FINISHED) 170 break; 171 172 /* Wait for more data. */ 173 if (fp->f_flag & O_NONBLOCK) { 174 error = EWOULDBLOCK; 175 break; 176 } 177 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx); 178 if (error != 0) 179 break; 180 } 181 182 tty_unlock(tp); 183 184 return (error); 185} 186 187static int 188ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 189 int flags, struct thread *td) 190{ 191 struct tty *tp = fp->f_data; 192 struct pts_softc *psc = tty_softc(tp); 193 char ib[256], *ibstart; 194 size_t iblen, rintlen; 195 int error = 0; 196 197 if (uio->uio_resid == 0) 198 return (0); 199 200 for (;;) { 201 ibstart = ib; 202 iblen = MIN(uio->uio_resid, sizeof ib); 203 error = uiomove(ib, iblen, uio); 204 205 tty_lock(tp); 206 if (error != 0) { 207 iblen = 0; 208 goto done; 209 } 210 211 /* 212 * When possible, avoid the slow path. rint_bypass() 213 * copies all input to the input queue at once. 214 */ 215 MPASS(iblen > 0); 216 do { 217 rintlen = ttydisc_rint_simple(tp, ibstart, iblen); 218 ibstart += rintlen; 219 iblen -= rintlen; 220 if (iblen == 0) { 221 /* All data written. */ 222 break; 223 } 224 225 /* Maybe the device isn't used anyway. */ 226 if (psc->pts_flags & PTS_FINISHED) { 227 error = EIO; 228 goto done; 229 } 230 231 /* Wait for more data. */ 232 if (fp->f_flag & O_NONBLOCK) { 233 error = EWOULDBLOCK; 234 goto done; 235 } 236 237 /* Wake up users on the slave side. */ 238 ttydisc_rint_done(tp); 239 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx); 240 if (error != 0) 241 goto done; 242 } while (iblen > 0); 243 244 if (uio->uio_resid == 0) 245 break; 246 tty_unlock(tp); 247 } 248 249done: ttydisc_rint_done(tp); 250 tty_unlock(tp); 251 252 /* 253 * Don't account for the part of the buffer that we couldn't 254 * pass to the TTY. 255 */ 256 uio->uio_resid += iblen; 257 return (error); 258} 259 260static int 261ptsdev_ioctl(struct file *fp, u_long cmd, void *data, 262 struct ucred *active_cred, struct thread *td) 263{ 264 struct tty *tp = fp->f_data; 265 struct pts_softc *psc = tty_softc(tp); 266 int error = 0, sig; 267 268 switch (cmd) { 269 case FIODTYPE: 270 *(int *)data = D_TTY; 271 return (0); 272 case FIONBIO: 273 /* This device supports non-blocking operation. */ 274 return (0); 275 case FIONREAD: 276 tty_lock(tp); 277 if (psc->pts_flags & PTS_FINISHED) { 278 /* Force read() to be called. */ 279 *(int *)data = 1; 280 } else { 281 *(int *)data = ttydisc_getc_poll(tp); 282 } 283 tty_unlock(tp); 284 return (0); 285 case FIODGNAME: 286#ifdef COMPAT_FREEBSD32 287 case FIODGNAME_32: 288#endif 289 { 290 struct fiodgname_arg *fgn; 291 const char *p; 292 int i; 293 294 /* Reverse device name lookups, for ptsname() and ttyname(). */ 295 fgn = data; 296 p = tty_devname(tp); 297 i = strlen(p) + 1; 298 if (i > fgn->len) 299 return (EINVAL); 300 return (copyout(p, fiodgname_buf_get_ptr(fgn, cmd), i)); 301 } 302 303 /* 304 * We need to implement TIOCGPGRP and TIOCGSID here again. When 305 * called on the pseudo-terminal master, it should not check if 306 * the terminal is the foreground terminal of the calling 307 * process. 308 * 309 * TIOCGETA is also implemented here. Various Linux PTY routines 310 * often call isatty(), which is implemented by tcgetattr(). 311 */ 312#ifdef PTS_LINUX 313 case TIOCGETA: 314 /* Obtain terminal flags through tcgetattr(). */ 315 tty_lock(tp); 316 *(struct termios*)data = tp->t_termios; 317 tty_unlock(tp); 318 return (0); 319#endif /* PTS_LINUX */ 320 case TIOCSETAF: 321 case TIOCSETAW: 322 /* 323 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and 324 * TCSADRAIN into something different. If an application would 325 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may 326 * deadlock waiting for all data to be read. 327 */ 328 cmd = TIOCSETA; 329 break; 330#if defined(PTS_COMPAT) || defined(PTS_LINUX) 331 case TIOCGPTN: 332 /* 333 * Get the device unit number. 334 */ 335 if (psc->pts_unit < 0) 336 return (ENOTTY); 337 *(unsigned int *)data = psc->pts_unit; 338 return (0); 339#endif /* PTS_COMPAT || PTS_LINUX */ 340 case TIOCGPGRP: 341 /* Get the foreground process group ID. */ 342 tty_lock(tp); 343 if (tp->t_pgrp != NULL) 344 *(int *)data = tp->t_pgrp->pg_id; 345 else 346 *(int *)data = NO_PID; 347 tty_unlock(tp); 348 return (0); 349 case TIOCGSID: 350 /* Get the session leader process ID. */ 351 tty_lock(tp); 352 if (tp->t_session == NULL) 353 error = ENOTTY; 354 else 355 *(int *)data = tp->t_session->s_sid; 356 tty_unlock(tp); 357 return (error); 358 case TIOCPTMASTER: 359 /* Yes, we are a pseudo-terminal master. */ 360 return (0); 361 case TIOCSIG: 362 /* Signal the foreground process group. */ 363 sig = *(int *)data; 364 if (sig < 1 || sig >= NSIG) 365 return (EINVAL); 366 367 tty_lock(tp); 368 tty_signal_pgrp(tp, sig); 369 tty_unlock(tp); 370 return (0); 371 case TIOCPKT: 372 /* Enable/disable packet mode. */ 373 tty_lock(tp); 374 if (*(int *)data) 375 psc->pts_flags |= PTS_PKT; 376 else 377 psc->pts_flags &= ~PTS_PKT; 378 tty_unlock(tp); 379 return (0); 380 } 381 382 /* Just redirect this ioctl to the slave device. */ 383 tty_lock(tp); 384 error = tty_ioctl(tp, cmd, data, fp->f_flag, td); 385 tty_unlock(tp); 386 if (error == ENOIOCTL) 387 error = ENOTTY; 388 389 return (error); 390} 391 392static int 393ptsdev_poll(struct file *fp, int events, struct ucred *active_cred, 394 struct thread *td) 395{ 396 struct tty *tp = fp->f_data; 397 struct pts_softc *psc = tty_softc(tp); 398 int revents = 0; 399 400 tty_lock(tp); 401 402 if (psc->pts_flags & PTS_FINISHED) { 403 /* Slave device is not opened. */ 404 tty_unlock(tp); 405 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP); 406 } 407 408 if (events & (POLLIN|POLLRDNORM)) { 409 /* See if we can getc something. */ 410 if (ttydisc_getc_poll(tp) || 411 (psc->pts_flags & PTS_PKT && psc->pts_pkt)) 412 revents |= events & (POLLIN|POLLRDNORM); 413 } 414 if (events & (POLLOUT|POLLWRNORM)) { 415 /* See if we can rint something. */ 416 if (ttydisc_rint_poll(tp)) 417 revents |= events & (POLLOUT|POLLWRNORM); 418 } 419 420 /* 421 * No need to check for POLLHUP here. This device cannot be used 422 * as a callout device, which means we always have a carrier, 423 * because the master is. 424 */ 425 426 if (revents == 0) { 427 /* 428 * This code might look misleading, but the naming of 429 * poll events on this side is the opposite of the slave 430 * device. 431 */ 432 if (events & (POLLIN|POLLRDNORM)) 433 selrecord(td, &psc->pts_outpoll); 434 if (events & (POLLOUT|POLLWRNORM)) 435 selrecord(td, &psc->pts_inpoll); 436 } 437 438 tty_unlock(tp); 439 440 return (revents); 441} 442 443/* 444 * kqueue support. 445 */ 446 447static void 448pts_kqops_read_detach(struct knote *kn) 449{ 450 struct file *fp = kn->kn_fp; 451 struct tty *tp = fp->f_data; 452 struct pts_softc *psc = tty_softc(tp); 453 454 knlist_remove(&psc->pts_outpoll.si_note, kn, 0); 455} 456 457static int 458pts_kqops_read_event(struct knote *kn, long hint) 459{ 460 struct file *fp = kn->kn_fp; 461 struct tty *tp = fp->f_data; 462 struct pts_softc *psc = tty_softc(tp); 463 464 if (psc->pts_flags & PTS_FINISHED) { 465 kn->kn_flags |= EV_EOF; 466 return (1); 467 } else { 468 kn->kn_data = ttydisc_getc_poll(tp); 469 return (kn->kn_data > 0); 470 } 471} 472 473static void 474pts_kqops_write_detach(struct knote *kn) 475{ 476 struct file *fp = kn->kn_fp; 477 struct tty *tp = fp->f_data; 478 struct pts_softc *psc = tty_softc(tp); 479 480 knlist_remove(&psc->pts_inpoll.si_note, kn, 0); 481} 482 483static int 484pts_kqops_write_event(struct knote *kn, long hint) 485{ 486 struct file *fp = kn->kn_fp; 487 struct tty *tp = fp->f_data; 488 struct pts_softc *psc = tty_softc(tp); 489 490 if (psc->pts_flags & PTS_FINISHED) { 491 kn->kn_flags |= EV_EOF; 492 return (1); 493 } else { 494 kn->kn_data = ttydisc_rint_poll(tp); 495 return (kn->kn_data > 0); 496 } 497} 498 499static struct filterops pts_kqops_read = { 500 .f_isfd = 1, 501 .f_detach = pts_kqops_read_detach, 502 .f_event = pts_kqops_read_event, 503}; 504static struct filterops pts_kqops_write = { 505 .f_isfd = 1, 506 .f_detach = pts_kqops_write_detach, 507 .f_event = pts_kqops_write_event, 508}; 509 510static int 511ptsdev_kqfilter(struct file *fp, struct knote *kn) 512{ 513 struct tty *tp = fp->f_data; 514 struct pts_softc *psc = tty_softc(tp); 515 int error = 0; 516 517 tty_lock(tp); 518 519 switch (kn->kn_filter) { 520 case EVFILT_READ: 521 kn->kn_fop = &pts_kqops_read; 522 knlist_add(&psc->pts_outpoll.si_note, kn, 1); 523 break; 524 case EVFILT_WRITE: 525 kn->kn_fop = &pts_kqops_write; 526 knlist_add(&psc->pts_inpoll.si_note, kn, 1); 527 break; 528 default: 529 error = EINVAL; 530 break; 531 } 532 533 tty_unlock(tp); 534 return (error); 535} 536 537static int 538ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, 539 struct thread *td) 540{ 541 struct tty *tp = fp->f_data; 542#ifdef PTS_EXTERNAL 543 struct pts_softc *psc = tty_softc(tp); 544#endif /* PTS_EXTERNAL */ 545 struct cdev *dev = tp->t_dev; 546 547 /* 548 * According to POSIX, we must implement an fstat(). This also 549 * makes this implementation compatible with Linux binaries, 550 * because Linux calls fstat() on the pseudo-terminal master to 551 * obtain st_rdev. 552 * 553 * XXX: POSIX also mentions we must fill in st_dev, but how? 554 */ 555 556 bzero(sb, sizeof *sb); 557#ifdef PTS_EXTERNAL 558 if (psc->pts_cdev != NULL) 559 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev); 560 else 561#endif /* PTS_EXTERNAL */ 562 sb->st_ino = sb->st_rdev = tty_udev(tp); 563 564 sb->st_atim = dev->si_atime; 565 sb->st_ctim = dev->si_ctime; 566 sb->st_mtim = dev->si_mtime; 567 sb->st_uid = dev->si_uid; 568 sb->st_gid = dev->si_gid; 569 sb->st_mode = dev->si_mode | S_IFCHR; 570 571 return (0); 572} 573 574static int 575ptsdev_close(struct file *fp, struct thread *td) 576{ 577 struct tty *tp = fp->f_data; 578 579 /* Deallocate TTY device. */ 580 tty_lock(tp); 581 tty_rel_gone(tp); 582 583 /* 584 * Open of /dev/ptmx or /dev/ptyXX changes the type of file 585 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode 586 * use count, we need to decrement it, and possibly do other 587 * required cleanup. 588 */ 589 if (fp->f_vnode != NULL) 590 return (vnops.fo_close(fp, td)); 591 592 return (0); 593} 594 595static int 596ptsdev_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 597{ 598 struct tty *tp; 599 600 kif->kf_type = KF_TYPE_PTS; 601 tp = fp->f_data; 602 kif->kf_un.kf_pts.kf_pts_dev = tty_udev(tp); 603 kif->kf_un.kf_pts.kf_pts_dev_freebsd11 = 604 kif->kf_un.kf_pts.kf_pts_dev; /* truncate */ 605 strlcpy(kif->kf_path, tty_devname(tp), sizeof(kif->kf_path)); 606 return (0); 607} 608 609static struct fileops ptsdev_ops = { 610 .fo_read = ptsdev_read, 611 .fo_write = ptsdev_write, 612 .fo_truncate = invfo_truncate, 613 .fo_ioctl = ptsdev_ioctl, 614 .fo_poll = ptsdev_poll, 615 .fo_kqfilter = ptsdev_kqfilter, 616 .fo_stat = ptsdev_stat, 617 .fo_close = ptsdev_close, 618 .fo_chmod = invfo_chmod, 619 .fo_chown = invfo_chown, 620 .fo_sendfile = invfo_sendfile, 621 .fo_fill_kinfo = ptsdev_fill_kinfo, 622 .fo_flags = DFLAG_PASSABLE, 623}; 624 625/* 626 * Driver-side hooks. 627 */ 628 629static void 630ptsdrv_outwakeup(struct tty *tp) 631{ 632 struct pts_softc *psc = tty_softc(tp); 633 634 cv_broadcast(&psc->pts_outwait); 635 selwakeup(&psc->pts_outpoll); 636 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0); 637} 638 639static void 640ptsdrv_inwakeup(struct tty *tp) 641{ 642 struct pts_softc *psc = tty_softc(tp); 643 644 cv_broadcast(&psc->pts_inwait); 645 selwakeup(&psc->pts_inpoll); 646 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0); 647} 648 649static int 650ptsdrv_open(struct tty *tp) 651{ 652 struct pts_softc *psc = tty_softc(tp); 653 654 psc->pts_flags &= ~PTS_FINISHED; 655 656 return (0); 657} 658 659static void 660ptsdrv_close(struct tty *tp) 661{ 662 struct pts_softc *psc = tty_softc(tp); 663 664 /* Wake up any blocked readers/writers. */ 665 psc->pts_flags |= PTS_FINISHED; 666 ptsdrv_outwakeup(tp); 667 ptsdrv_inwakeup(tp); 668} 669 670static void 671ptsdrv_pktnotify(struct tty *tp, char event) 672{ 673 struct pts_softc *psc = tty_softc(tp); 674 675 /* 676 * Clear conflicting flags. 677 */ 678 679 switch (event) { 680 case TIOCPKT_STOP: 681 psc->pts_pkt &= ~TIOCPKT_START; 682 break; 683 case TIOCPKT_START: 684 psc->pts_pkt &= ~TIOCPKT_STOP; 685 break; 686 case TIOCPKT_NOSTOP: 687 psc->pts_pkt &= ~TIOCPKT_DOSTOP; 688 break; 689 case TIOCPKT_DOSTOP: 690 psc->pts_pkt &= ~TIOCPKT_NOSTOP; 691 break; 692 } 693 694 psc->pts_pkt |= event; 695 ptsdrv_outwakeup(tp); 696} 697 698static void 699ptsdrv_free(void *softc) 700{ 701 struct pts_softc *psc = softc; 702 703 /* Make device number available again. */ 704 if (psc->pts_unit >= 0) 705 free_unr(pts_pool, psc->pts_unit); 706 707 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0); 708 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1); 709 crfree(psc->pts_cred); 710 711 seldrain(&psc->pts_inpoll); 712 seldrain(&psc->pts_outpoll); 713 knlist_destroy(&psc->pts_inpoll.si_note); 714 knlist_destroy(&psc->pts_outpoll.si_note); 715 716#ifdef PTS_EXTERNAL 717 /* Destroy master device as well. */ 718 if (psc->pts_cdev != NULL) 719 destroy_dev_sched(psc->pts_cdev); 720#endif /* PTS_EXTERNAL */ 721 722 free(psc, M_PTS); 723} 724 725static struct ttydevsw pts_class = { 726 .tsw_flags = TF_NOPREFIX, 727 .tsw_outwakeup = ptsdrv_outwakeup, 728 .tsw_inwakeup = ptsdrv_inwakeup, 729 .tsw_open = ptsdrv_open, 730 .tsw_close = ptsdrv_close, 731 .tsw_pktnotify = ptsdrv_pktnotify, 732 .tsw_free = ptsdrv_free, 733}; 734 735#ifndef PTS_EXTERNAL 736static 737#endif /* !PTS_EXTERNAL */ 738int 739pts_alloc(int fflags, struct thread *td, struct file *fp) 740{ 741 int unit, ok, error; 742 struct tty *tp; 743 struct pts_softc *psc; 744 struct proc *p = td->td_proc; 745 struct ucred *cred = td->td_ucred; 746 747 /* Resource limiting. */ 748 PROC_LOCK(p); 749 error = racct_add(p, RACCT_NPTS, 1); 750 if (error != 0) { 751 PROC_UNLOCK(p); 752 return (EAGAIN); 753 } 754 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 755 if (!ok) { 756 racct_sub(p, RACCT_NPTS, 1); 757 PROC_UNLOCK(p); 758 return (EAGAIN); 759 } 760 PROC_UNLOCK(p); 761 762 /* Try to allocate a new pts unit number. */ 763 unit = alloc_unr(pts_pool); 764 if (unit < 0) { 765 racct_sub(p, RACCT_NPTS, 1); 766 chgptscnt(cred->cr_ruidinfo, -1, 0); 767 return (EAGAIN); 768 } 769 770 /* Allocate TTY and softc. */ 771 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 772 cv_init(&psc->pts_inwait, "ptsin"); 773 cv_init(&psc->pts_outwait, "ptsout"); 774 775 psc->pts_unit = unit; 776 psc->pts_cred = crhold(cred); 777 778 tp = tty_alloc(&pts_class, psc); 779 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 780 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 781 782 /* Expose the slave device as well. */ 783 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit); 784 785 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 786 787 return (0); 788} 789 790#ifdef PTS_EXTERNAL 791int 792pts_alloc_external(int fflags, struct thread *td, struct file *fp, 793 struct cdev *dev, const char *name) 794{ 795 int ok, error; 796 struct tty *tp; 797 struct pts_softc *psc; 798 struct proc *p = td->td_proc; 799 struct ucred *cred = td->td_ucred; 800 801 /* Resource limiting. */ 802 PROC_LOCK(p); 803 error = racct_add(p, RACCT_NPTS, 1); 804 if (error != 0) { 805 PROC_UNLOCK(p); 806 return (EAGAIN); 807 } 808 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS)); 809 if (!ok) { 810 racct_sub(p, RACCT_NPTS, 1); 811 PROC_UNLOCK(p); 812 return (EAGAIN); 813 } 814 PROC_UNLOCK(p); 815 816 /* Allocate TTY and softc. */ 817 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO); 818 cv_init(&psc->pts_inwait, "ptsin"); 819 cv_init(&psc->pts_outwait, "ptsout"); 820 821 psc->pts_unit = -1; 822 psc->pts_cdev = dev; 823 psc->pts_cred = crhold(cred); 824 825 tp = tty_alloc(&pts_class, psc); 826 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx); 827 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx); 828 829 /* Expose the slave device as well. */ 830 tty_makedev(tp, td->td_ucred, "%s", name); 831 832 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops); 833 834 return (0); 835} 836#endif /* PTS_EXTERNAL */ 837 838int 839sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap) 840{ 841 int error, fd; 842 struct file *fp; 843 844 /* 845 * POSIX states it's unspecified when other flags are passed. We 846 * don't allow this. 847 */ 848 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC)) 849 return (EINVAL); 850 851 error = falloc(td, &fp, &fd, uap->flags); 852 if (error) 853 return (error); 854 855 /* Allocate the actual pseudo-TTY. */ 856 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp); 857 if (error != 0) { 858 fdclose(td, fp, fd); 859 fdrop(fp, td); 860 return (error); 861 } 862 863 /* Pass it back to userspace. */ 864 td->td_retval[0] = fd; 865 fdrop(fp, td); 866 867 return (0); 868} 869 870static void 871pts_init(void *unused) 872{ 873 874 pts_pool = new_unrhdr(0, INT_MAX, NULL); 875} 876 877SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL); 878