1 /* $NetBSD: pty.c,v 1.16 2000/07/10 11:16:38 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993, 1994 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)pty.c 8.3 (Berkeley) 5/16/94"; 40 #else 41 __RCSID("$NetBSD: pty.c,v 1.16 2000/07/10 11:16:38 ad Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include <sys/types.h> 46 #include <sys/ioctl.h> 47 #include <sys/stat.h> 48 49 #include <assert.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <grp.h> 53 #include <stdio.h> 54 #include <string.h> 55 #include <termios.h> 56 #include <unistd.h> 57 #include <util.h> 58 59 #define TTY_LETTERS "pqrstuvwxyzPQRST" 60 61 int 62 openpty(int *amaster, int *aslave, char *name, struct termios *termp, 63 struct winsize *winp) 64 { 65 static char line[] = "/dev/XtyXX"; 66 const char *cp1, *cp2; 67 int master, slave; 68 gid_t ttygid; 69 struct group *gr; 70 71 _DIAGASSERT(amaster != NULL); 72 _DIAGASSERT(aslave != NULL); 73 /* name may be NULL */ 74 /* termp may be NULL */ 75 /* winp may be NULL */ 76 77 if ((gr = getgrnam("tty")) != NULL) 78 ttygid = gr->gr_gid; 79 else 80 ttygid = (gid_t) -1; 81 82 for (cp1 = TTY_LETTERS; *cp1; cp1++) { 83 line[8] = *cp1; 84 for (cp2 = "0123456789abcdef"; *cp2; cp2++) { 85 line[5] = 'p'; 86 line[9] = *cp2; 87 if ((master = open(line, O_RDWR, 0)) == -1) { 88 if (errno == ENOENT) 89 return (-1); /* out of ptys */ 90 } else { 91 line[5] = 't'; 92 (void) chown(line, getuid(), ttygid); 93 (void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP); 94 (void) revoke(line); 95 if ((slave = open(line, O_RDWR, 0)) != -1) { 96 *amaster = master; 97 *aslave = slave; 98 if (name) 99 strcpy(name, line); 100 if (termp) 101 (void) tcsetattr(slave, 102 TCSAFLUSH, termp); 103 if (winp) 104 (void) ioctl(slave, TIOCSWINSZ, 105 winp); 106 return (0); 107 } 108 (void) close(master); 109 } 110 } 111 } 112 errno = ENOENT; /* out of ptys */ 113 return (-1); 114 } 115 116 pid_t 117 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp) 118 { 119 int master, slave; 120 pid_t pid; 121 122 _DIAGASSERT(amaster != NULL); 123 /* name may be NULL */ 124 /* termp may be NULL */ 125 /* winp may be NULL */ 126 127 if (openpty(&master, &slave, name, termp, winp) == -1) 128 return (-1); 129 switch (pid = fork()) { 130 case -1: 131 return (-1); 132 case 0: 133 /* 134 * child 135 */ 136 (void) close(master); 137 login_tty(slave); 138 return (0); 139 } 140 /* 141 * parent 142 */ 143 *amaster = master; 144 (void) close(slave); 145 return (pid); 146 } 147