1 /* $NetBSD: pty.c,v 1.20 2003/08/07 16:45:00 agc 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. 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/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)pty.c 8.3 (Berkeley) 5/16/94"; 36 #else 37 __RCSID("$NetBSD: pty.c,v 1.20 2003/08/07 16:45:00 agc Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <sys/types.h> 42 #include <sys/ioctl.h> 43 #include <sys/stat.h> 44 45 #include <assert.h> 46 #include <errno.h> 47 #include <fcntl.h> 48 #include <grp.h> 49 #include <stdio.h> 50 #include <string.h> 51 #include <termios.h> 52 #include <unistd.h> 53 #include <util.h> 54 55 /* 56 * XXX: `v' removed until no ports are using console devices which use ttyv0 57 */ 58 #define TTY_LETTERS "pqrstuwxyzPQRST" 59 #define TTY_OLD_SUFFIX "0123456789abcdef" 60 #define TTY_NEW_SUFFIX "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" 61 62 int 63 openpty(int *amaster, int *aslave, char *name, struct termios *termp, 64 struct winsize *winp) 65 { 66 static char line[] = "/dev/XtyXX"; 67 const char *cp1, *cp2, *cp; 68 int master, slave, tries = 0; 69 gid_t ttygid; 70 struct group *gr; 71 72 _DIAGASSERT(amaster != NULL); 73 _DIAGASSERT(aslave != NULL); 74 /* name may be NULL */ 75 /* termp may be NULL */ 76 /* winp may be NULL */ 77 78 if ((gr = getgrnam("tty")) != NULL) 79 ttygid = gr->gr_gid; 80 else 81 ttygid = (gid_t) -1; 82 83 for (cp1 = TTY_LETTERS; *cp1; cp1++) { 84 tries = 0; 85 line[8] = *cp1; 86 for (cp = cp2 = TTY_OLD_SUFFIX TTY_NEW_SUFFIX; *cp2; cp2++) { 87 line[5] = 'p'; 88 line[9] = *cp2; 89 if ((master = open(line, O_RDWR, 0)) == -1) { 90 if (errno == ENOENT) { 91 if (cp2 - cp + 1 < sizeof(TTY_OLD_SUFFIX)) 92 return (-1); /* out of ptys */ 93 else 94 break; 95 } 96 } else { 97 line[5] = 't'; 98 (void) chown(line, getuid(), ttygid); 99 (void) chmod(line, S_IRUSR|S_IWUSR|S_IWGRP); 100 (void) revoke(line); 101 if ((slave = open(line, O_RDWR, 0)) != -1) { 102 *amaster = master; 103 *aslave = slave; 104 if (name) 105 strcpy(name, line); 106 if (termp) 107 (void) tcsetattr(slave, 108 TCSAFLUSH, termp); 109 if (winp) 110 (void) ioctl(slave, TIOCSWINSZ, 111 winp); 112 return (0); 113 } 114 (void) close(master); 115 } 116 } 117 } 118 errno = ENOENT; /* out of ptys */ 119 return (-1); 120 } 121 122 pid_t 123 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp) 124 { 125 int master, slave; 126 pid_t pid; 127 128 _DIAGASSERT(amaster != NULL); 129 /* name may be NULL */ 130 /* termp may be NULL */ 131 /* winp may be NULL */ 132 133 if (openpty(&master, &slave, name, termp, winp) == -1) 134 return (-1); 135 switch (pid = fork()) { 136 case -1: 137 return (-1); 138 case 0: 139 /* 140 * child 141 */ 142 (void) close(master); 143 login_tty(slave); 144 return (0); 145 } 146 /* 147 * parent 148 */ 149 *amaster = master; 150 (void) close(slave); 151 return (pid); 152 } 153