diff options
Diffstat (limited to 'pty.c')
-rw-r--r-- | pty.c | 275 |
1 files changed, 275 insertions, 0 deletions
@@ -0,0 +1,275 @@ +/* + * 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 1.16 2000/09/07 21:13:37 markus Exp $"); + +#include <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 + +#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 */ +#ifdef 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; + } + /* 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)); + if (ioctl(*ttyfd, I_PUSH, "ttcompat") < 0) + error("ioctl I_PUSH ttcompat: %.100s", strerror(errno)); + 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]); + *ptyfd = open(buf, O_RDWR | O_NOCTTY); + if (*ptyfd < 0) + continue; + snprintf(namebuf, namebuflen, "/dev/tty%c%c", + ptymajors[i / num_minors], ptyminors[i % num_minors]); + + /* 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; + + /* 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 */ + fd = open(ttyname, O_RDWR); + if (fd < 0) + error("%.100s: %.100s", ttyname, strerror(errno)); + else + close(fd); + + /* 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)); +} |