1 /* $OpenBSD: pty.c,v 1.9 2002/06/09 22:18:43 fgsch Exp $ */ 2 /*- 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by the University of 17 * California, Berkeley and its contributors. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #if defined(LIBC_SCCS) && !defined(lint) 36 /* from: static char sccsid[] = "@(#)pty.c 8.1 (Berkeley) 6/4/93"; */ 37 static const char rcsid[] = "$Id: pty.c,v 1.9 2002/06/09 22:18:43 fgsch Exp $"; 38 #endif /* LIBC_SCCS and not lint */ 39 40 #include <sys/cdefs.h> 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 #include <sys/ioctl.h> 44 #include <fcntl.h> 45 #include <termios.h> 46 #include <errno.h> 47 #include <unistd.h> 48 #include <stdio.h> 49 #include <string.h> 50 #include <grp.h> 51 52 #include "util.h" 53 54 #define TTY_LETTERS "pqrstuvwxyzPQRST" 55 56 int 57 openpty(amaster, aslave, name, termp, winp) 58 int *amaster, *aslave; 59 char *name; 60 struct termios *termp; 61 struct winsize *winp; 62 { 63 char line[] = "/dev/ptyXX"; 64 register const char *cp1, *cp2; 65 register int master, slave, ttygid; 66 struct group *gr; 67 68 if ((gr = getgrnam("tty")) != NULL) 69 ttygid = gr->gr_gid; 70 else 71 ttygid = -1; 72 73 for (cp1 = TTY_LETTERS; *cp1; cp1++) { 74 line[8] = *cp1; 75 for (cp2 = "0123456789abcdef"; *cp2; cp2++) { 76 line[9] = *cp2; 77 line[5] = 'p'; 78 if ((master = open(line, O_RDWR, 0)) == -1) { 79 if (errno == ENOENT) 80 return (-1); /* out of ptys */ 81 } else { 82 line[5] = 't'; 83 (void) chown(line, getuid(), ttygid); 84 (void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP); 85 (void) revoke(line); 86 if ((slave = open(line, O_RDWR, 0)) != -1) { 87 *amaster = master; 88 *aslave = slave; 89 if (name) { 90 /* 91 * Manual page says "at least 92 * 16 characters". 93 */ 94 strlcpy(name, line, 16); 95 } 96 if (termp) 97 (void) tcsetattr(slave, 98 TCSAFLUSH, termp); 99 if (winp) 100 (void) ioctl(slave, TIOCSWINSZ, 101 (char *)winp); 102 return (0); 103 } 104 (void) close(master); 105 } 106 } 107 } 108 errno = ENOENT; /* out of ptys */ 109 return (-1); 110 } 111 112 pid_t 113 forkpty(amaster, name, termp, winp) 114 int *amaster; 115 char *name; 116 struct termios *termp; 117 struct winsize *winp; 118 { 119 int master, slave; 120 pid_t pid; 121 122 if (openpty(&master, &slave, name, termp, winp) == -1) 123 return (-1); 124 switch (pid = fork()) { 125 case -1: 126 return (-1); 127 case 0: 128 /* 129 * child 130 */ 131 (void) close(master); 132 login_tty(slave); 133 return (0); 134 } 135 /* 136 * parent 137 */ 138 *amaster = master; 139 (void) close(slave); 140 return (pid); 141 } 142