[openssh.git] / pty.c

/*
 *
 * pty.c
 *
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 *
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 *
 * Created: Fri Mar 17 04:37:25 1995 ylo
 *
 * Allocating a pseudo-terminal, and making it the controlling tty.
 *
 */

#include "includes.h"
RCSID("$OpenBSD: pty.c,v 1.14 2000/06/20 01:39:43 markus Exp $");

#ifdef HAVE_UTIL_H
# include <util.h>
#endif /* HAVE_UTIL_H */

#include "pty.h"
#include "ssh.h"

/* Pty allocated with _getpty gets broken if we do I_PUSH:es to it. */
#if defined(HAVE__GETPTY) || defined(HAVE_OPENPTY)
#undef HAVE_DEV_PTMX
#endif

#ifdef HAVE_PTY_H
# include <pty.h>
#endif
#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H)
# include <sys/stropts.h>
#endif

#ifndef O_NOCTTY
#define O_NOCTTY 0
#endif

/*
 * Allocates and opens a pty.  Returns 0 if no pty could be allocated, or
 * nonzero if a pty was successfully allocated.  On success, open file
 * descriptors for the pty and tty sides and the name of the tty side are
 * returned (the buffer must be able to hold at least 64 characters).
 */

int
pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, int namebuflen)
{
#if defined(HAVE_OPENPTY) || defined(BSD4_4)
	/* openpty(3) exists in OSF/1 and some other os'es */
	char buf[64];
	int i;

	i = openpty(ptyfd, ttyfd, buf, NULL, NULL);
	if (i < 0) {
		error("openpty: %.100s", strerror(errno));
		return 0;
	}
	strlcpy(namebuf, buf, namebuflen);	/* possible truncation */
	return 1;
#else /* HAVE_OPENPTY */
#ifdef HAVE__GETPTY
	/*
	 * _getpty(3) exists in SGI Irix 4.x, 5.x & 6.x -- it generates more
	 * pty's automagically when needed
	 */
	char *slave;

	slave = _getpty(ptyfd, O_RDWR, 0622, 0);
	if (slave == NULL) {
		error("_getpty: %.100s", strerror(errno));
		return 0;
	}
	strlcpy(namebuf, slave, namebuflen);
	/* Open the slave side. */
	*ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
	if (*ttyfd < 0) {
		error("%.200s: %.100s", namebuf, strerror(errno));
		close(*ptyfd);
		return 0;
	}
	return 1;
#else /* HAVE__GETPTY */
#if defined(HAVE_DEV_PTMX)
	/*
	 * This code is used e.g. on Solaris 2.x.  (Note that Solaris 2.3
	 * also has bsd-style ptys, but they simply do not work.)
	 */
	int ptm;
	char *pts;

	ptm = open("/dev/ptmx", O_RDWR | O_NOCTTY);
	if (ptm < 0) {
		error("/dev/ptmx: %.100s", strerror(errno));
		return 0;
	}
	if (grantpt(ptm) < 0) {
		error("grantpt: %.100s", strerror(errno));
		return 0;
	}
	if (unlockpt(ptm) < 0) {
		error("unlockpt: %.100s", strerror(errno));
		return 0;
	}
	pts = ptsname(ptm);
	if (pts == NULL)
		error("Slave pty side name could not be obtained.");
	strlcpy(namebuf, pts, namebuflen);
	*ptyfd = ptm;

	/* Open the slave side. */
	*ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
	if (*ttyfd < 0) {
		error("%.100s: %.100s", namebuf, strerror(errno));
		close(*ptyfd);
		return 0;
	}
#ifndef HAVE_CYGWIN
	/* Push the appropriate streams modules, as described in Solaris pts(7). */
	if (ioctl(*ttyfd, I_PUSH, "ptem") < 0)
		error("ioctl I_PUSH ptem: %.100s", strerror(errno));
	if (ioctl(*ttyfd, I_PUSH, "ldterm") < 0)
		error("ioctl I_PUSH ldterm: %.100s", strerror(errno));
#ifndef _HPUX_SOURCE
	if (ioctl(*ttyfd, I_PUSH, "ttcompat") < 0)
		error("ioctl I_PUSH ttcompat: %.100s", strerror(errno));
#endif
#endif
	return 1;
#else /* HAVE_DEV_PTMX */
#ifdef HAVE_DEV_PTS_AND_PTC
	/* AIX-style pty code. */
	const char *name;

	*ptyfd = open("/dev/ptc", O_RDWR | O_NOCTTY);
	if (*ptyfd < 0) {
		error("Could not open /dev/ptc: %.100s", strerror(errno));
		return 0;
	}
	name = ttyname(*ptyfd);
	if (!name)
		fatal("Open of /dev/ptc returns device for which ttyname fails.");
	strlcpy(namebuf, name, namebuflen);
	*ttyfd = open(name, O_RDWR | O_NOCTTY);
	if (*ttyfd < 0) {
		error("Could not open pty slave side %.100s: %.100s",
		      name, strerror(errno));
		close(*ptyfd);
		return 0;
	}
	return 1;
#else /* HAVE_DEV_PTS_AND_PTC */
	/* BSD-style pty code. */
	char buf[64];
	int i;
	const char *ptymajors = "pqrstuvwxyzabcdefghijklmnoABCDEFGHIJKLMNOPQRSTUVWXYZ";
	const char *ptyminors = "0123456789abcdef";
	int num_minors = strlen(ptyminors);
	int num_ptys = strlen(ptymajors) * num_minors;

	for (i = 0; i < num_ptys; i++) {
		snprintf(buf, sizeof buf, "/dev/pty%c%c", ptymajors[i / num_minors],
			 ptyminors[i % num_minors]);
		snprintf(namebuf, namebuflen, "/dev/tty%c%c",
		    ptymajors[i / num_minors], ptyminors[i % num_minors]);

		*ptyfd = open(buf, O_RDWR | O_NOCTTY);
		if (*ptyfd < 0) {
			/* Try SCO style naming */
			snprintf(buf, sizeof buf, "/dev/ptyp%d", i);
			snprintf(namebuf, namebuflen, "/dev/ttyp%d", i);
			*ptyfd = open(buf, O_RDWR | O_NOCTTY);
			if (*ptyfd < 0)
				continue;
		}	
			
		/* Open the slave side. */
		*ttyfd = open(namebuf, O_RDWR | O_NOCTTY);
		if (*ttyfd < 0) {
			error("%.100s: %.100s", namebuf, strerror(errno));
			close(*ptyfd);
			return 0;
		}
		return 1;
	}
	return 0;
#endif /* HAVE_DEV_PTS_AND_PTC */
#endif /* HAVE_DEV_PTMX */
#endif /* HAVE__GETPTY */
#endif /* HAVE_OPENPTY */
}

/* Releases the tty.  Its ownership is returned to root, and permissions to 0666. */

void
pty_release(const char *ttyname)
{
	if (chown(ttyname, (uid_t) 0, (gid_t) 0) < 0)
		error("chown %.100s 0 0 failed: %.100s", ttyname, strerror(errno));
	if (chmod(ttyname, (mode_t) 0666) < 0)
		error("chmod %.100s 0666 failed: %.100s", ttyname, strerror(errno));
}

/* Makes the tty the processes controlling tty and sets it to sane modes. */

void
pty_make_controlling_tty(int *ttyfd, const char *ttyname)
{
	int fd;
#ifdef USE_VHANGUP
	void *old;
#endif /* USE_VHANGUP */

	/* First disconnect from the old controlling tty. */
#ifdef TIOCNOTTY
	fd = open("/dev/tty", O_RDWR | O_NOCTTY);
	if (fd >= 0) {
		(void) ioctl(fd, TIOCNOTTY, NULL);
		close(fd);
	}
#endif /* TIOCNOTTY */
	if (setsid() < 0)
		error("setsid: %.100s", strerror(errno));

	/*
	 * Verify that we are successfully disconnected from the controlling
	 * tty.
	 */
	fd = open("/dev/tty", O_RDWR | O_NOCTTY);
	if (fd >= 0) {
		error("Failed to disconnect from controlling tty.");
		close(fd);
	}
	/* Make it our controlling tty. */
#ifdef TIOCSCTTY
	debug("Setting controlling tty using TIOCSCTTY.");
	/*
	 * We ignore errors from this, because HPSUX defines TIOCSCTTY, but
	 * returns EINVAL with these arguments, and there is absolutely no
	 * documentation.
	 */
	ioctl(*ttyfd, TIOCSCTTY, NULL);
#endif /* TIOCSCTTY */
#ifdef USE_VHANGUP
	old = signal(SIGHUP, SIG_IGN);
	vhangup();
	signal(SIGHUP, old);
#endif /* USE_VHANGUP */
	fd = open(ttyname, O_RDWR);
	if (fd < 0) {
		error("%.100s: %.100s", ttyname, strerror(errno));
	} else {
#ifdef USE_VHANGUP
		close(*ttyfd);
		*ttyfd = fd;
#else /* USE_VHANGUP */
		close(fd);
#endif /* USE_VHANGUP */
	}
	/* Verify that we now have a controlling tty. */
	fd = open("/dev/tty", O_WRONLY);
	if (fd < 0)
		error("open /dev/tty failed - could not set controlling tty: %.100s",
		      strerror(errno));
	else {
		close(fd);
	}
}

/* Changes the window size associated with the pty. */

void
pty_change_window_size(int ptyfd, int row, int col,
		       int xpixel, int ypixel)
{
	struct winsize w;
	w.ws_row = row;
	w.ws_col = col;
	w.ws_xpixel = xpixel;
	w.ws_ypixel = ypixel;
	(void) ioctl(ptyfd, TIOCSWINSZ, &w);
}

void
pty_setowner(struct passwd *pw, const char *ttyname)
{
	struct group *grp;
	gid_t gid;
	mode_t mode;

	/* Determine the group to make the owner of the tty. */
	grp = getgrnam("tty");
	if (grp) {
		gid = grp->gr_gid;
		mode = S_IRUSR | S_IWUSR | S_IWGRP;
	} else {
		gid = pw->pw_gid;
		mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
	}

	/* Change ownership of the tty. */
	if (chown(ttyname, pw->pw_uid, gid) < 0)
		fatal("chown(%.100s, %d, %d) failed: %.100s",
		    ttyname, pw->pw_uid, gid, strerror(errno));
	if (chmod(ttyname, mode) < 0)
		fatal("chmod(%.100s, 0%o) failed: %.100s",
		    ttyname, mode, strerror(errno));
}
Commit	Line	Data
8efc0c15	1	/*
6ae2364d	2	*
5260325f	3	* pty.c
6ae2364d	4	*
5260325f	5	* Author: Tatu Ylonen <ylo@cs.hut.fi>
6ae2364d	6	*
5260325f	7	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5260325f	8	* All rights reserved
6ae2364d	9	*
5260325f	10	* Created: Fri Mar 17 04:37:25 1995 ylo
6ae2364d	11	*
5260325f	12	* Allocating a pseudo-terminal, and making it the controlling tty.
6ae2364d	13	*
5260325f	14	*/
8efc0c15	15
8efc0c15	16	#include "includes.h"
74fc9186	17	RCSID("$OpenBSD: pty.c,v 1.14 2000/06/20 01:39:43 markus Exp $");
8efc0c15	18
884bcb37	19	#ifdef HAVE_UTIL_H
	20	# include <util.h>
	21	#endif /* HAVE_UTIL_H */
	22
5260325f	23	#include "pty.h"
	24	#include "ssh.h"
	25
8efc0c15	26	/* Pty allocated with _getpty gets broken if we do I_PUSH:es to it. */
	27	#if defined(HAVE__GETPTY) \|\| defined(HAVE_OPENPTY)
	28	#undef HAVE_DEV_PTMX
	29	#endif
	30
6d8c4ea4	31	#ifdef HAVE_PTY_H
	32	# include <pty.h>
	33	#endif
	34	#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H)
	35	# include <sys/stropts.h>
	36	#endif
	37
8efc0c15	38	#ifndef O_NOCTTY
	39	#define O_NOCTTY 0
	40	#endif
	41
aa3378df	42	/*
	43	* Allocates and opens a pty. Returns 0 if no pty could be allocated, or
	44	* nonzero if a pty was successfully allocated. On success, open file
	45	* descriptors for the pty and tty sides and the name of the tty side are
	46	* returned (the buffer must be able to hold at least 64 characters).
	47	*/
8efc0c15	48
6ae2364d	49	int
a408af76	50	pty_allocate(int ptyfd, int ttyfd, char *namebuf, int namebuflen)
8efc0c15	51	{
a408af76	52	#if defined(HAVE_OPENPTY) \|\| defined(BSD4_4)
5260325f	53	/* openpty(3) exists in OSF/1 and some other os'es */
a408af76	54	char buf[64];
5260325f	55	int i;
8efc0c15	56
a408af76	57	i = openpty(ptyfd, ttyfd, buf, NULL, NULL);
5260325f	58	if (i < 0) {
	59	error("openpty: %.100s", strerror(errno));
	60	return 0;
	61	}
a408af76	62	strlcpy(namebuf, buf, namebuflen); /* possible truncation */
5260325f	63	return 1;
8efc0c15	64	#else /* HAVE_OPENPTY */
8efc0c15	65	#ifdef HAVE__GETPTY
aa3378df	66	/*
	67	* _getpty(3) exists in SGI Irix 4.x, 5.x & 6.x -- it generates more
	68	* pty's automagically when needed
	69	*/
5260325f	70	char *slave;
	71
	72	slave = _getpty(ptyfd, O_RDWR, 0622, 0);
	73	if (slave == NULL) {
	74	error("_getpty: %.100s", strerror(errno));
	75	return 0;
	76	}
a408af76	77	strlcpy(namebuf, slave, namebuflen);
5260325f	78	/* Open the slave side. */
	79	*ttyfd = open(namebuf, O_RDWR \| O_NOCTTY);
	80	if (*ttyfd < 0) {
	81	error("%.200s: %.100s", namebuf, strerror(errno));
	82	close(*ptyfd);
	83	return 0;
	84	}
	85	return 1;
8efc0c15	86	#else /* HAVE__GETPTY */
a7effaac	87	#if defined(HAVE_DEV_PTMX)
aa3378df	88	/*
	89	* This code is used e.g. on Solaris 2.x. (Note that Solaris 2.3
	90	* also has bsd-style ptys, but they simply do not work.)
	91	*/
5260325f	92	int ptm;
	93	char *pts;
	94
	95	ptm = open("/dev/ptmx", O_RDWR \| O_NOCTTY);
	96	if (ptm < 0) {
	97	error("/dev/ptmx: %.100s", strerror(errno));
	98	return 0;
	99	}
	100	if (grantpt(ptm) < 0) {
	101	error("grantpt: %.100s", strerror(errno));
	102	return 0;
	103	}
	104	if (unlockpt(ptm) < 0) {
	105	error("unlockpt: %.100s", strerror(errno));
	106	return 0;
	107	}
	108	pts = ptsname(ptm);
	109	if (pts == NULL)
	110	error("Slave pty side name could not be obtained.");
a408af76	111	strlcpy(namebuf, pts, namebuflen);
5260325f	112	*ptyfd = ptm;
	113
	114	/* Open the slave side. */
	115	*ttyfd = open(namebuf, O_RDWR \| O_NOCTTY);
	116	if (*ttyfd < 0) {
	117	error("%.100s: %.100s", namebuf, strerror(errno));
	118	close(*ptyfd);
	119	return 0;
	120	}
3c62e7eb	121	#ifndef HAVE_CYGWIN
aa3378df	122	/* Push the appropriate streams modules, as described in Solaris pts(7). */
5260325f	123	if (ioctl(*ttyfd, I_PUSH, "ptem") < 0)
	124	error("ioctl I_PUSH ptem: %.100s", strerror(errno));
	125	if (ioctl(*ttyfd, I_PUSH, "ldterm") < 0)
	126	error("ioctl I_PUSH ldterm: %.100s", strerror(errno));
be48d23c	127	#ifndef _HPUX_SOURCE
5260325f	128	if (ioctl(*ttyfd, I_PUSH, "ttcompat") < 0)
5260325f	129	error("ioctl I_PUSH ttcompat: %.100s", strerror(errno));
3c62e7eb	130	#endif
be48d23c	131	#endif
5260325f	132	return 1;
8efc0c15	133	#else /* HAVE_DEV_PTMX */
8efc0c15	134	#ifdef HAVE_DEV_PTS_AND_PTC
5260325f	135	/* AIX-style pty code. */
5260325f	136	const char *name;
8efc0c15	137
5260325f	138	*ptyfd = open("/dev/ptc", O_RDWR \| O_NOCTTY);
	139	if (*ptyfd < 0) {
	140	error("Could not open /dev/ptc: %.100s", strerror(errno));
	141	return 0;
	142	}
	143	name = ttyname(*ptyfd);
	144	if (!name)
	145	fatal("Open of /dev/ptc returns device for which ttyname fails.");
a408af76	146	strlcpy(namebuf, name, namebuflen);
5260325f	147	*ttyfd = open(name, O_RDWR \| O_NOCTTY);
	148	if (*ttyfd < 0) {
	149	error("Could not open pty slave side %.100s: %.100s",
	150	name, strerror(errno));
	151	close(*ptyfd);
	152	return 0;
	153	}
	154	return 1;
8efc0c15	155	#else /* HAVE_DEV_PTS_AND_PTC */
5260325f	156	/* BSD-style pty code. */
	157	char buf[64];
	158	int i;
aa3378df	159	const char *ptymajors = "pqrstuvwxyzabcdefghijklmnoABCDEFGHIJKLMNOPQRSTUVWXYZ";
5260325f	160	const char *ptyminors = "0123456789abcdef";
	161	int num_minors = strlen(ptyminors);
	162	int num_ptys = strlen(ptymajors) * num_minors;
	163
	164	for (i = 0; i < num_ptys; i++) {
	165	snprintf(buf, sizeof buf, "/dev/pty%c%c", ptymajors[i / num_minors],
	166	ptyminors[i % num_minors]);
95f1eccc	167	snprintf(namebuf, namebuflen, "/dev/tty%c%c",
a408af76	168	ptymajors[i / num_minors], ptyminors[i % num_minors]);
5260325f	169
b5f90139	170	*ptyfd = open(buf, O_RDWR \| O_NOCTTY);
	171	if (*ptyfd < 0) {
	172	/* Try SCO style naming */
	173	snprintf(buf, sizeof buf, "/dev/ptyp%d", i);
	174	snprintf(namebuf, namebuflen, "/dev/ttyp%d", i);
	175	*ptyfd = open(buf, O_RDWR \| O_NOCTTY);
	176	if (*ptyfd < 0)
	177	continue;
	178	}
	179
5260325f	180	/* Open the slave side. */
	181	*ttyfd = open(namebuf, O_RDWR \| O_NOCTTY);
	182	if (*ttyfd < 0) {
	183	error("%.100s: %.100s", namebuf, strerror(errno));
	184	close(*ptyfd);
	185	return 0;
	186	}
	187	return 1;
8efc0c15	188	}
5260325f	189	return 0;
8efc0c15	190	#endif /* HAVE_DEV_PTS_AND_PTC */
	191	#endif /* HAVE_DEV_PTMX */
	192	#endif /* HAVE__GETPTY */
	193	#endif /* HAVE_OPENPTY */
	194	}
	195
5260325f	196	/* Releases the tty. Its ownership is returned to root, and permissions to 0666. */
8efc0c15	197
6ae2364d	198	void
5260325f	199	pty_release(const char *ttyname)
8efc0c15	200	{
3276571c	201	if (chown(ttyname, (uid_t) 0, (gid_t) 0) < 0)
817175bc	202	error("chown %.100s 0 0 failed: %.100s", ttyname, strerror(errno));
3276571c	203	if (chmod(ttyname, (mode_t) 0666) < 0)
817175bc	204	error("chmod %.100s 0666 failed: %.100s", ttyname, strerror(errno));
8efc0c15	205	}
	206
	207	/* Makes the tty the processes controlling tty and sets it to sane modes. */
	208
6ae2364d	209	void
5260325f	210	pty_make_controlling_tty(int ttyfd, const char ttyname)
8efc0c15	211	{
5260325f	212	int fd;
3c62e7eb	213	#ifdef USE_VHANGUP
4e577b89	214	void *old;
3c62e7eb	215	#endif /* USE_VHANGUP */
8efc0c15	216
5260325f	217	/* First disconnect from the old controlling tty. */
8efc0c15	218	#ifdef TIOCNOTTY
5260325f	219	fd = open("/dev/tty", O_RDWR \| O_NOCTTY);
	220	if (fd >= 0) {
	221	(void) ioctl(fd, TIOCNOTTY, NULL);
	222	close(fd);
	223	}
8efc0c15	224	#endif /* TIOCNOTTY */
5260325f	225	if (setsid() < 0)
	226	error("setsid: %.100s", strerror(errno));
	227
aa3378df	228	/*
	229	* Verify that we are successfully disconnected from the controlling
	230	* tty.
	231	*/
5260325f	232	fd = open("/dev/tty", O_RDWR \| O_NOCTTY);
	233	if (fd >= 0) {
	234	error("Failed to disconnect from controlling tty.");
	235	close(fd);
	236	}
	237	/* Make it our controlling tty. */
8efc0c15	238	#ifdef TIOCSCTTY
5260325f	239	debug("Setting controlling tty using TIOCSCTTY.");
aa3378df	240	/*
	241	* We ignore errors from this, because HPSUX defines TIOCSCTTY, but
	242	* returns EINVAL with these arguments, and there is absolutely no
	243	* documentation.
	244	*/
5260325f	245	ioctl(*ttyfd, TIOCSCTTY, NULL);
8efc0c15	246	#endif /* TIOCSCTTY */
3c62e7eb	247	#ifdef USE_VHANGUP
4e577b89	248	old = signal(SIGHUP, SIG_IGN);
	249	vhangup();
	250	signal(SIGHUP, old);
3c62e7eb	251	#endif /* USE_VHANGUP */
5260325f	252	fd = open(ttyname, O_RDWR);
4e577b89	253	if (fd < 0) {
5260325f	254	error("%.100s: %.100s", ttyname, strerror(errno));
4e577b89	255	} else {
3c62e7eb	256	#ifdef USE_VHANGUP
4e577b89	257	close(*ttyfd);
4e577b89	258	*ttyfd = fd;
3c62e7eb	259	#else /* USE_VHANGUP */
5260325f	260	close(fd);
3c62e7eb	261	#endif /* USE_VHANGUP */
4e577b89	262	}
5260325f	263	/* Verify that we now have a controlling tty. */
	264	fd = open("/dev/tty", O_WRONLY);
	265	if (fd < 0)
	266	error("open /dev/tty failed - could not set controlling tty: %.100s",
	267	strerror(errno));
	268	else {
	269	close(fd);
	270	}
8efc0c15	271	}
	272
	273	/* Changes the window size associated with the pty. */
	274
6ae2364d	275	void
5260325f	276	pty_change_window_size(int ptyfd, int row, int col,
5260325f	277	int xpixel, int ypixel)
8efc0c15	278	{
5260325f	279	struct winsize w;
	280	w.ws_row = row;
	281	w.ws_col = col;
	282	w.ws_xpixel = xpixel;
	283	w.ws_ypixel = ypixel;
	284	(void) ioctl(ptyfd, TIOCSWINSZ, &w);
8efc0c15	285	}
817175bc	286
	287	void
	288	pty_setowner(struct passwd pw, const char ttyname)
	289	{
	290	struct group *grp;
	291	gid_t gid;
	292	mode_t mode;
	293
	294	/* Determine the group to make the owner of the tty. */
	295	grp = getgrnam("tty");
	296	if (grp) {
	297	gid = grp->gr_gid;
	298	mode = S_IRUSR \| S_IWUSR \| S_IWGRP;
	299	} else {
	300	gid = pw->pw_gid;
	301	mode = S_IRUSR \| S_IWUSR \| S_IWGRP \| S_IWOTH;
	302	}
	303
	304	/* Change ownership of the tty. */
	305	if (chown(ttyname, pw->pw_uid, gid) < 0)
	306	fatal("chown(%.100s, %d, %d) failed: %.100s",
	307	ttyname, pw->pw_uid, gid, strerror(errno));
	308	if (chmod(ttyname, mode) < 0)
	309	fatal("chmod(%.100s, 0%o) failed: %.100s",
	310	ttyname, mode, strerror(errno));
	311	}