2 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
5 * Portions of this software were developed under sponsorship from Snow
6 * B.V., the Netherlands.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 /* Add compatibility bits for FreeBSD. */
35 /* Add pty(4) compat bits. */
37 /* Add bits to make Linux binaries work. */
40 #include <sys/param.h>
42 #include <sys/condvar.h>
44 #include <sys/fcntl.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>
53 #include <sys/racct.h>
54 #include <sys/resourcevar.h>
55 #include <sys/serial.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>
64 #include <sys/ttycom.h>
66 #include <machine/stdarg.h>
69 * Our utmp(5) format is limited to 8-byte TTY line names. This means
70 * we can at most allocate 1000 pseudo-terminals ("pts/999"). Allow
71 * users to increase this number, assuming they have manually increased
74 static struct unrhdr *pts_pool;
76 static MALLOC_DEFINE(M_PTS, "pts", "pseudo tty device");
82 * (t) locked by tty_lock()
83 * (c) const until freeing
86 int pts_unit; /* (c) Device unit number. */
87 unsigned int pts_flags; /* (t) Device flags. */
88 #define PTS_PKT 0x1 /* Packet mode. */
89 #define PTS_FINISHED 0x2 /* Return errors on read()/write(). */
90 char pts_pkt; /* (t) Unread packet mode data. */
92 struct cv pts_inwait; /* (t) Blocking write() on master. */
93 struct selinfo pts_inpoll; /* (t) Select queue for write(). */
94 struct cv pts_outwait; /* (t) Blocking read() on master. */
95 struct selinfo pts_outpoll; /* (t) Select queue for read(). */
98 struct cdev *pts_cdev; /* (c) Master device node. */
99 #endif /* PTS_EXTERNAL */
101 struct ucred *pts_cred; /* (c) Resource limit. */
105 * Controller-side file operations.
109 ptsdev_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
110 int flags, struct thread *td)
112 struct tty *tp = fp->f_data;
113 struct pts_softc *psc = tty_softc(tp);
117 if (uio->uio_resid == 0)
124 * Implement packet mode. When packet mode is turned on,
125 * the first byte contains a bitmask of events that
126 * occured (start, stop, flush, window size, etc).
128 if (psc->pts_flags & PTS_PKT && psc->pts_pkt) {
133 error = ureadc(pkt, uio);
138 * Transmit regular data.
140 * XXX: We shouldn't use ttydisc_getc_poll()! Even
141 * though in this implementation, there is likely going
142 * to be data, we should just call ttydisc_getc_uio()
143 * and use its return value to sleep.
145 if (ttydisc_getc_poll(tp)) {
146 if (psc->pts_flags & PTS_PKT) {
148 * XXX: Small race. Fortunately PTY
149 * consumers aren't multithreaded.
153 error = ureadc(TIOCPKT_DATA, uio);
159 error = ttydisc_getc_uio(tp, uio);
163 /* Maybe the device isn't used anyway. */
164 if (psc->pts_flags & PTS_FINISHED)
167 /* Wait for more data. */
168 if (fp->f_flag & O_NONBLOCK) {
172 error = cv_wait_sig(&psc->pts_outwait, tp->t_mtx);
183 ptsdev_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
184 int flags, struct thread *td)
186 struct tty *tp = fp->f_data;
187 struct pts_softc *psc = tty_softc(tp);
188 char ib[256], *ibstart;
189 size_t iblen, rintlen;
192 if (uio->uio_resid == 0)
197 iblen = MIN(uio->uio_resid, sizeof ib);
198 error = uiomove(ib, iblen, uio);
207 * When possible, avoid the slow path. rint_bypass()
208 * copies all input to the input queue at once.
212 rintlen = ttydisc_rint_simple(tp, ibstart, iblen);
216 /* All data written. */
220 /* Maybe the device isn't used anyway. */
221 if (psc->pts_flags & PTS_FINISHED) {
226 /* Wait for more data. */
227 if (fp->f_flag & O_NONBLOCK) {
232 /* Wake up users on the slave side. */
233 ttydisc_rint_done(tp);
234 error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx);
239 if (uio->uio_resid == 0)
244 done: ttydisc_rint_done(tp);
248 * Don't account for the part of the buffer that we couldn't
251 uio->uio_resid += iblen;
256 ptsdev_truncate(struct file *fp, off_t length, struct ucred *active_cred,
264 ptsdev_ioctl(struct file *fp, u_long cmd, void *data,
265 struct ucred *active_cred, struct thread *td)
267 struct tty *tp = fp->f_data;
268 struct pts_softc *psc = tty_softc(tp);
273 /* This device supports non-blocking operation. */
277 if (psc->pts_flags & PTS_FINISHED) {
278 /* Force read() to be called. */
281 *(int *)data = ttydisc_getc_poll(tp);
286 struct fiodgname_arg *fgn;
290 /* Reverse device name lookups, for ptsname() and ttyname(). */
296 return copyout(p, fgn->buf, i);
300 * We need to implement TIOCGPGRP and TIOCGSID here again. When
301 * called on the pseudo-terminal master, it should not check if
302 * the terminal is the foreground terminal of the calling
305 * TIOCGETA is also implemented here. Various Linux PTY routines
306 * often call isatty(), which is implemented by tcgetattr().
310 /* Obtain terminal flags through tcgetattr(). */
312 *(struct termios*)data = tp->t_termios;
315 #endif /* PTS_LINUX */
319 * We must make sure we turn tcsetattr() calls of TCSAFLUSH and
320 * TCSADRAIN into something different. If an application would
321 * call TCSAFLUSH or TCSADRAIN on the master descriptor, it may
322 * deadlock waiting for all data to be read.
326 #if defined(PTS_COMPAT) || defined(PTS_LINUX)
329 * Get the device unit number.
331 if (psc->pts_unit < 0)
333 *(unsigned int *)data = psc->pts_unit;
335 #endif /* PTS_COMPAT || PTS_LINUX */
337 /* Get the foreground process group ID. */
339 if (tp->t_pgrp != NULL)
340 *(int *)data = tp->t_pgrp->pg_id;
342 *(int *)data = NO_PID;
346 /* Get the session leader process ID. */
348 if (tp->t_session == NULL)
351 *(int *)data = tp->t_session->s_sid;
355 /* Yes, we are a pseudo-terminal master. */
358 /* Signal the foreground process group. */
360 if (sig < 1 || sig >= NSIG)
364 tty_signal_pgrp(tp, sig);
368 /* Enable/disable packet mode. */
371 psc->pts_flags |= PTS_PKT;
373 psc->pts_flags &= ~PTS_PKT;
378 /* Just redirect this ioctl to the slave device. */
380 error = tty_ioctl(tp, cmd, data, fp->f_flag, td);
382 if (error == ENOIOCTL)
389 ptsdev_poll(struct file *fp, int events, struct ucred *active_cred,
392 struct tty *tp = fp->f_data;
393 struct pts_softc *psc = tty_softc(tp);
398 if (psc->pts_flags & PTS_FINISHED) {
399 /* Slave device is not opened. */
401 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
404 if (events & (POLLIN|POLLRDNORM)) {
405 /* See if we can getc something. */
406 if (ttydisc_getc_poll(tp) ||
407 (psc->pts_flags & PTS_PKT && psc->pts_pkt))
408 revents |= events & (POLLIN|POLLRDNORM);
410 if (events & (POLLOUT|POLLWRNORM)) {
411 /* See if we can rint something. */
412 if (ttydisc_rint_poll(tp))
413 revents |= events & (POLLOUT|POLLWRNORM);
417 * No need to check for POLLHUP here. This device cannot be used
418 * as a callout device, which means we always have a carrier,
419 * because the master is.
424 * This code might look misleading, but the naming of
425 * poll events on this side is the opposite of the slave
428 if (events & (POLLIN|POLLRDNORM))
429 selrecord(td, &psc->pts_outpoll);
430 if (events & (POLLOUT|POLLWRNORM))
431 selrecord(td, &psc->pts_inpoll);
444 pts_kqops_read_detach(struct knote *kn)
446 struct file *fp = kn->kn_fp;
447 struct tty *tp = fp->f_data;
448 struct pts_softc *psc = tty_softc(tp);
450 knlist_remove(&psc->pts_outpoll.si_note, kn, 0);
454 pts_kqops_read_event(struct knote *kn, long hint)
456 struct file *fp = kn->kn_fp;
457 struct tty *tp = fp->f_data;
458 struct pts_softc *psc = tty_softc(tp);
460 if (psc->pts_flags & PTS_FINISHED) {
461 kn->kn_flags |= EV_EOF;
464 kn->kn_data = ttydisc_getc_poll(tp);
465 return (kn->kn_data > 0);
470 pts_kqops_write_detach(struct knote *kn)
472 struct file *fp = kn->kn_fp;
473 struct tty *tp = fp->f_data;
474 struct pts_softc *psc = tty_softc(tp);
476 knlist_remove(&psc->pts_inpoll.si_note, kn, 0);
480 pts_kqops_write_event(struct knote *kn, long hint)
482 struct file *fp = kn->kn_fp;
483 struct tty *tp = fp->f_data;
484 struct pts_softc *psc = tty_softc(tp);
486 if (psc->pts_flags & PTS_FINISHED) {
487 kn->kn_flags |= EV_EOF;
490 kn->kn_data = ttydisc_rint_poll(tp);
491 return (kn->kn_data > 0);
495 static struct filterops pts_kqops_read = {
497 .f_detach = pts_kqops_read_detach,
498 .f_event = pts_kqops_read_event,
500 static struct filterops pts_kqops_write = {
502 .f_detach = pts_kqops_write_detach,
503 .f_event = pts_kqops_write_event,
507 ptsdev_kqfilter(struct file *fp, struct knote *kn)
509 struct tty *tp = fp->f_data;
510 struct pts_softc *psc = tty_softc(tp);
515 switch (kn->kn_filter) {
517 kn->kn_fop = &pts_kqops_read;
518 knlist_add(&psc->pts_outpoll.si_note, kn, 1);
521 kn->kn_fop = &pts_kqops_write;
522 knlist_add(&psc->pts_inpoll.si_note, kn, 1);
534 ptsdev_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
537 struct tty *tp = fp->f_data;
539 struct pts_softc *psc = tty_softc(tp);
540 #endif /* PTS_EXTERNAL */
541 struct cdev *dev = tp->t_dev;
544 * According to POSIX, we must implement an fstat(). This also
545 * makes this implementation compatible with Linux binaries,
546 * because Linux calls fstat() on the pseudo-terminal master to
549 * XXX: POSIX also mentions we must fill in st_dev, but how?
552 bzero(sb, sizeof *sb);
554 if (psc->pts_cdev != NULL)
555 sb->st_ino = sb->st_rdev = dev2udev(psc->pts_cdev);
557 #endif /* PTS_EXTERNAL */
558 sb->st_ino = sb->st_rdev = tty_udev(tp);
560 sb->st_atim = dev->si_atime;
561 sb->st_ctim = dev->si_ctime;
562 sb->st_mtim = dev->si_mtime;
563 sb->st_uid = dev->si_uid;
564 sb->st_gid = dev->si_gid;
565 sb->st_mode = dev->si_mode | S_IFCHR;
571 ptsdev_close(struct file *fp, struct thread *td)
573 struct tty *tp = fp->f_data;
575 /* Deallocate TTY device. */
580 * Open of /dev/ptmx or /dev/ptyXX changes the type of file
581 * from DTYPE_VNODE to DTYPE_PTS. vn_open() increases vnode
582 * use count, we need to decrement it, and possibly do other
585 if (fp->f_vnode != NULL)
586 return (vnops.fo_close(fp, td));
591 static struct fileops ptsdev_ops = {
592 .fo_read = ptsdev_read,
593 .fo_write = ptsdev_write,
594 .fo_truncate = ptsdev_truncate,
595 .fo_ioctl = ptsdev_ioctl,
596 .fo_poll = ptsdev_poll,
597 .fo_kqfilter = ptsdev_kqfilter,
598 .fo_stat = ptsdev_stat,
599 .fo_close = ptsdev_close,
600 .fo_chmod = invfo_chmod,
601 .fo_chown = invfo_chown,
602 .fo_flags = DFLAG_PASSABLE,
610 ptsdrv_outwakeup(struct tty *tp)
612 struct pts_softc *psc = tty_softc(tp);
614 cv_broadcast(&psc->pts_outwait);
615 selwakeup(&psc->pts_outpoll);
616 KNOTE_LOCKED(&psc->pts_outpoll.si_note, 0);
620 ptsdrv_inwakeup(struct tty *tp)
622 struct pts_softc *psc = tty_softc(tp);
624 cv_broadcast(&psc->pts_inwait);
625 selwakeup(&psc->pts_inpoll);
626 KNOTE_LOCKED(&psc->pts_inpoll.si_note, 0);
630 ptsdrv_open(struct tty *tp)
632 struct pts_softc *psc = tty_softc(tp);
634 psc->pts_flags &= ~PTS_FINISHED;
640 ptsdrv_close(struct tty *tp)
642 struct pts_softc *psc = tty_softc(tp);
644 /* Wake up any blocked readers/writers. */
645 psc->pts_flags |= PTS_FINISHED;
646 ptsdrv_outwakeup(tp);
651 ptsdrv_pktnotify(struct tty *tp, char event)
653 struct pts_softc *psc = tty_softc(tp);
656 * Clear conflicting flags.
661 psc->pts_pkt &= ~TIOCPKT_START;
664 psc->pts_pkt &= ~TIOCPKT_STOP;
667 psc->pts_pkt &= ~TIOCPKT_DOSTOP;
670 psc->pts_pkt &= ~TIOCPKT_NOSTOP;
674 psc->pts_pkt |= event;
675 ptsdrv_outwakeup(tp);
679 ptsdrv_free(void *softc)
681 struct pts_softc *psc = softc;
683 /* Make device number available again. */
684 if (psc->pts_unit >= 0)
685 free_unr(pts_pool, psc->pts_unit);
687 chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0);
688 racct_sub_cred(psc->pts_cred, RACCT_NPTS, 1);
689 crfree(psc->pts_cred);
691 seldrain(&psc->pts_inpoll);
692 seldrain(&psc->pts_outpoll);
693 knlist_destroy(&psc->pts_inpoll.si_note);
694 knlist_destroy(&psc->pts_outpoll.si_note);
697 /* Destroy master device as well. */
698 if (psc->pts_cdev != NULL)
699 destroy_dev_sched(psc->pts_cdev);
700 #endif /* PTS_EXTERNAL */
705 static struct ttydevsw pts_class = {
706 .tsw_flags = TF_NOPREFIX,
707 .tsw_outwakeup = ptsdrv_outwakeup,
708 .tsw_inwakeup = ptsdrv_inwakeup,
709 .tsw_open = ptsdrv_open,
710 .tsw_close = ptsdrv_close,
711 .tsw_pktnotify = ptsdrv_pktnotify,
712 .tsw_free = ptsdrv_free,
717 #endif /* !PTS_EXTERNAL */
719 pts_alloc(int fflags, struct thread *td, struct file *fp)
723 struct pts_softc *psc;
724 struct proc *p = td->td_proc;
725 struct ucred *cred = td->td_ucred;
727 /* Resource limiting. */
729 error = racct_add(p, RACCT_NPTS, 1);
734 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(p, RLIMIT_NPTS));
736 racct_sub(p, RACCT_NPTS, 1);
742 /* Try to allocate a new pts unit number. */
743 unit = alloc_unr(pts_pool);
745 racct_sub(p, RACCT_NPTS, 1);
746 chgptscnt(cred->cr_ruidinfo, -1, 0);
750 /* Allocate TTY and softc. */
751 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
752 cv_init(&psc->pts_inwait, "ptsin");
753 cv_init(&psc->pts_outwait, "ptsout");
755 psc->pts_unit = unit;
756 psc->pts_cred = crhold(cred);
758 tp = tty_alloc(&pts_class, psc);
759 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
760 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
762 /* Expose the slave device as well. */
763 tty_makedev(tp, td->td_ucred, "pts/%u", psc->pts_unit);
765 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
772 pts_alloc_external(int fflags, struct thread *td, struct file *fp,
773 struct cdev *dev, const char *name)
777 struct pts_softc *psc;
778 struct proc *p = td->td_proc;
779 struct ucred *cred = td->td_ucred;
781 /* Resource limiting. */
783 error = racct_add(p, RACCT_NPTS, 1);
788 ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(p, RLIMIT_NPTS));
790 racct_sub(p, RACCT_NPTS, 1);
796 /* Allocate TTY and softc. */
797 psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
798 cv_init(&psc->pts_inwait, "ptsin");
799 cv_init(&psc->pts_outwait, "ptsout");
803 psc->pts_cred = crhold(cred);
805 tp = tty_alloc(&pts_class, psc);
806 knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
807 knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);
809 /* Expose the slave device as well. */
810 tty_makedev(tp, td->td_ucred, "%s", name);
812 finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);
816 #endif /* PTS_EXTERNAL */
819 sys_posix_openpt(struct thread *td, struct posix_openpt_args *uap)
825 * POSIX states it's unspecified when other flags are passed. We
828 if (uap->flags & ~(O_RDWR|O_NOCTTY|O_CLOEXEC))
831 error = falloc(td, &fp, &fd, uap->flags);
835 /* Allocate the actual pseudo-TTY. */
836 error = pts_alloc(FFLAGS(uap->flags & O_ACCMODE), td, fp);
838 fdclose(td->td_proc->p_fd, fp, fd, td);
843 /* Pass it back to userspace. */
844 td->td_retval[0] = fd;
851 pts_init(void *unused)
854 pts_pool = new_unrhdr(0, INT_MAX, NULL);
857 SYSINIT(pts, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pts_init, NULL);