diff --git a/sshpty.c b/sshpty.c
new file mode 100644
index 0000000..aca6f02
--- /dev/null
+++ b/sshpty.c
@@ -0,0 +1,342 @@
+/*
+ * 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: pty.c,v 1.22 2001/02/08 19:30:52 itojun Exp $");
+
+#ifdef HAVE_UTIL_H
+# include <util.h>
+#endif /* HAVE_UTIL_H */
+
+#include "sshpty.h"
+#include "log.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;
+
+	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).
+	 * 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)
+				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));
+		}
+	}
+}