1 /* $OpenBSD: pty.c,v 1.20 2016/08/30 14:44:45 guenther Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/types.h> 33 #include <sys/stat.h> 34 #include <sys/ioctl.h> 35 #include <fcntl.h> 36 #include <termios.h> 37 #include <errno.h> 38 #include <unistd.h> 39 #include <stdio.h> 40 #include <string.h> 41 #include <grp.h> 42 #include <sys/tty.h> 43 44 #include "util.h" 45 46 int 47 openpty(int *amaster, int *aslave, char *name, struct termios *termp, 48 struct winsize *winp) 49 { 50 int master, slave, fd; 51 struct ptmget ptm; 52 53 /* 54 * Use /dev/ptm and the PTMGET ioctl to get a properly set up and 55 * owned pty/tty pair. 56 */ 57 fd = open(PATH_PTMDEV, O_RDWR|O_CLOEXEC); 58 if (fd == -1) 59 return (-1); 60 if ((ioctl(fd, PTMGET, &ptm) == -1)) { 61 close(fd); 62 return (-1); 63 } 64 close(fd); 65 master = ptm.cfd; 66 slave = ptm.sfd; 67 if (name) { 68 /* 69 * Manual page says "at least 16 characters". 70 */ 71 strlcpy(name, ptm.sn, 16); 72 } 73 *amaster = master; 74 *aslave = slave; 75 if (termp) 76 (void) tcsetattr(slave, TCSAFLUSH, termp); 77 if (winp) 78 (void) ioctl(slave, TIOCSWINSZ, winp); 79 return (0); 80 } 81 82 pid_t 83 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp) 84 { 85 int master, slave; 86 pid_t pid; 87 88 if (openpty(&master, &slave, name, termp, winp) == -1) 89 return (-1); 90 switch (pid = fork()) { 91 case -1: 92 (void) close(master); 93 (void) close(slave); 94 return (-1); 95 case 0: 96 /* 97 * child 98 */ 99 (void) close(master); 100 login_tty(slave); 101 return (0); 102 } 103 /* 104 * parent 105 */ 106 *amaster = master; 107 (void) close(slave); 108 return (pid); 109 } 110