sshpty.c - security/openssh-library - Rivoreo Source Code Repositories

 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
  * Allocating a pseudo-terminal, and making it the controlling tty.
  *
  * As far as I am concerned, the code I have written for this software
  * can be used freely for any purpose.  Any derived versions of this
  * software must be clearly marked as such, and if the derived work is
  * incompatible with the protocol description in the RFC file, it must be
  * called by a name other than "ssh" or "Secure Shell".
  */

 #include "includes.h"
 RCSID("$OpenBSD: sshpty.c,v 1.2 2001/07/18 21:10:43 markus Exp $");

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

 #include "sshpty.h"
 #include "log.h"
 #include "misc.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 *name;
 	int i;

 	i = openpty(ptyfd, ttyfd, NULL, NULL, NULL);
 	if (i < 0) {
 		error("openpty: %.100s", strerror(errno));
 		return 0;
 	}
 	name = ttyname(*ttyfd);
 	if (!name)
 		fatal("openpty returns device for which ttyname fails.");

 	strlcpy(namebuf, name, 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;
 	mysig_t old_signal;

 	ptm = open("/dev/ptmx", O_RDWR | O_NOCTTY);
 	if (ptm < 0) {
 		error("/dev/ptmx: %.100s", strerror(errno));
 		return 0;
 	}
 	old_signal = mysignal(SIGCHLD, SIG_DFL);
 	if (grantpt(ptm) < 0) {
 		error("grantpt: %.100s", strerror(errno));
 		return 0;
 	}
 	mysignal(SIGCHLD, old_signal);
 	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).
 	 * HP-UX pts(7) doesn't have ttcompat module.
 	 */
 	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
 	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(_PATH_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(_PATH_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.");
 	if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0)
 		error("ioctl(TIOCSCTTY): %.100s", strerror(errno));
 #endif /* TIOCSCTTY */
 #ifdef HAVE_NEWS4
 	if (setpgrp(0,0) < 0)
 		error("SETPGRP %s",strerror(errno));
 #endif /* HAVE_NEWS4 */
 #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(_PATH_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;
 	struct stat st;

 	/* 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 owner and mode of the tty as required.
 	 * Warn but continue if filesystem is read-only and the uids match.
 	 */
 	if (stat(ttyname, &st))
 		fatal("stat(%.100s) failed: %.100s", ttyname,
 		    strerror(errno));

 	if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
 		if (chown(ttyname, pw->pw_uid, gid) < 0) {
 			if (errno == EROFS &&
 			   (st.st_uid == pw->pw_uid || st.st_uid == 0))
 				error("chown(%.100s, %d, %d) failed: %.100s",
 				      ttyname, pw->pw_uid, gid,
 				      strerror(errno));
 			else
 				fatal("chown(%.100s, %d, %d) failed: %.100s",
 				      ttyname, pw->pw_uid, gid,
 				      strerror(errno));
 		}
 	}

 	if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) {
 		if (chmod(ttyname, mode) < 0) {
 			if (errno == EROFS &&
 			    (st.st_mode & (S_IRGRP | S_IROTH)) == 0)
 				error("chmod(%.100s, 0%o) failed: %.100s",
 				      ttyname, mode, strerror(errno));
 			else
 				fatal("chmod(%.100s, 0%o) failed: %.100s",
 				      ttyname, mode, strerror(errno));
 		}
 	}
 }
	/*
	* Author: Tatu Ylonen <ylo@cs.hut.fi>
	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	* All rights reserved
	* Allocating a pseudo-terminal, and making it the controlling tty.
	*
	* As far as I am concerned, the code I have written for this software
	* can be used freely for any purpose. Any derived versions of this
	* software must be clearly marked as such, and if the derived work is
	* incompatible with the protocol description in the RFC file, it must be
	* called by a name other than "ssh" or "Secure Shell".
	*/

	#include "includes.h"
	RCSID("$OpenBSD: sshpty.c,v 1.2 2001/07/18 21:10:43 markus Exp $");

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

	#include "sshpty.h"
	#include "log.h"
	#include "misc.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 *name;
	int i;

	i = openpty(ptyfd, ttyfd, NULL, NULL, NULL);
	if (i < 0) {
	error("openpty: %.100s", strerror(errno));
	return 0;
	}
	name = ttyname(*ttyfd);
	if (!name)
	fatal("openpty returns device for which ttyname fails.");

	strlcpy(namebuf, name, 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;
	mysig_t old_signal;

	ptm = open("/dev/ptmx", O_RDWR \| O_NOCTTY);
	if (ptm < 0) {
	error("/dev/ptmx: %.100s", strerror(errno));
	return 0;
	}
	old_signal = mysignal(SIGCHLD, SIG_DFL);
	if (grantpt(ptm) < 0) {
	error("grantpt: %.100s", strerror(errno));
	return 0;
	}
	mysignal(SIGCHLD, old_signal);
	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).
	* HP-UX pts(7) doesn't have ttcompat module.
	*/
	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
	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(_PATH_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(_PATH_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.");
	if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0)
	error("ioctl(TIOCSCTTY): %.100s", strerror(errno));
	#endif /* TIOCSCTTY */
	#ifdef HAVE_NEWS4
	if (setpgrp(0,0) < 0)
	error("SETPGRP %s",strerror(errno));
	#endif /* HAVE_NEWS4 */
	#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(_PATH_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;
	struct stat st;

	/* 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 owner and mode of the tty as required.
	* Warn but continue if filesystem is read-only and the uids match.
	*/
	if (stat(ttyname, &st))
	fatal("stat(%.100s) failed: %.100s", ttyname,
	strerror(errno));

	if (st.st_uid != pw->pw_uid \|\| st.st_gid != gid) {
	if (chown(ttyname, pw->pw_uid, gid) < 0) {
	if (errno == EROFS &&
	(st.st_uid == pw->pw_uid \|\| st.st_uid == 0))
	error("chown(%.100s, %d, %d) failed: %.100s",
	ttyname, pw->pw_uid, gid,
	strerror(errno));
	else
	fatal("chown(%.100s, %d, %d) failed: %.100s",
	ttyname, pw->pw_uid, gid,
	strerror(errno));
	}
	}

	if ((st.st_mode & (S_IRWXU\|S_IRWXG\|S_IRWXO)) != mode) {
	if (chmod(ttyname, mode) < 0) {
	if (errno == EROFS &&
	(st.st_mode & (S_IRGRP \| S_IROTH)) == 0)
	error("chmod(%.100s, 0%o) failed: %.100s",
	ttyname, mode, strerror(errno));
	else
	fatal("chmod(%.100s, 0%o) failed: %.100s",
	ttyname, mode, strerror(errno));
	}
	}
	}