/* $OpenBSD: pty.c,v 1.15 2006/03/30 20:44:19 deraadt Exp $ */ /*- * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <sys/cdefs.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/ioctl.h> #include <fcntl.h> #include <termios.h> #include <errno.h> #include <unistd.h> #include <stdio.h> #include <string.h> #include <grp.h> #include <sys/tty.h> #include "util.h" #define TTY_LETTERS "pqrstuvwxyzPQRST" #define TTY_SUFFIX "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" int openpty(int *amaster, int *aslave, char *name, struct termios *termp, struct winsize *winp) { char line[] = "/dev/ptyXX"; const char *cp1, *cp2; int master, slave, fd; struct ptmget ptm; struct group *gr; gid_t ttygid; /* * Try to use /dev/ptm and the PTMGET ioctl to get a properly set up * and owned pty/tty pair. If this fails, (because we might not have * the ptm device, etc.) fall back to using the traditional method * of walking through the pty entries in /dev for the moment, until * there is less chance of people being seriously boned by running * kernels without /dev/ptm in them. */ fd = open(PATH_PTMDEV, O_RDWR, 0); if (fd == -1) goto walkit; if ((ioctl(fd, PTMGET, &ptm) == -1)) { close(fd); goto walkit; } close(fd); master = ptm.cfd; slave = ptm.sfd; if (name) { /* * Manual page says "at least 16 characters". */ strlcpy(name, ptm.sn, 16); } *amaster = master; *aslave = slave; if (termp) (void) tcsetattr(slave, TCSAFLUSH, termp); if (winp) (void) ioctl(slave, TIOCSWINSZ, winp); return (0); walkit: if ((gr = getgrnam("tty")) != NULL) ttygid = gr->gr_gid; else ttygid = (gid_t)-1; for (cp1 = TTY_LETTERS; *cp1; cp1++) { line[8] = *cp1; for (cp2 = TTY_SUFFIX; *cp2; cp2++) { line[9] = *cp2; line[5] = 'p'; if ((master = open(line, O_RDWR, 0)) == -1) { if (errno == ENOENT) return (-1); /* out of ptys */ } else { line[5] = 't'; (void) chown(line, getuid(), ttygid); (void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP); (void) revoke(line); if ((slave = open(line, O_RDWR, 0)) != -1) { *amaster = master; *aslave = slave; if (name) { /* * Manual page says "at least * 16 characters". */ strlcpy(name, line, 16); } if (termp) (void) tcsetattr(slave, TCSAFLUSH, termp); if (winp) (void) ioctl(slave, TIOCSWINSZ, winp); return (0); } (void) close(master); } } } errno = ENOENT; /* out of ptys */ return (-1); } pid_t forkpty(amaster, name, termp, winp) int *amaster; char *name; struct termios *termp; struct winsize *winp; { int master, slave; pid_t pid; if (openpty(&master, &slave, name, termp, winp) == -1) return (-1); switch (pid = fork()) { case -1: return (-1); case 0: /* * child */ (void) close(master); login_tty(slave); return (0); } /* * parent */ *amaster = master; (void) close(slave); return (pid); }