1 /* $NetBSD: pty.c,v 1.27 2004/11/25 02:49:46 christos 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 1.27 2004/11/25 02:49:46 christos 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 *term, 64 struct winsize *winp) 65 { 66 static char line[] = "/dev/XtyXX"; 67 const char *cp1, *cp2, *cp, *linep; 68 int master, slave; 69 gid_t ttygid; 70 mode_t mode; 71 struct group *gr; 72 73 _DIAGASSERT(amaster != NULL); 74 _DIAGASSERT(aslave != NULL); 75 /* name may be NULL */ 76 /* term may be NULL */ 77 /* winp may be NULL */ 78 79 if ((master = open("/dev/ptm", O_RDWR)) != -1) { 80 struct ptmget pt; 81 if (ioctl(master, TIOCPTMGET, &pt) != -1) { 82 (void)close(master); 83 master = pt.cfd; 84 slave = pt.sfd; 85 linep = pt.sn; 86 goto gotit; 87 } 88 } 89 90 if ((gr = getgrnam("tty")) != NULL) { 91 ttygid = gr->gr_gid; 92 mode = S_IRUSR|S_IWUSR|S_IWGRP; 93 } else { 94 ttygid = getgid(); 95 mode = S_IRUSR|S_IWUSR; 96 } 97 98 for (cp1 = TTY_LETTERS; *cp1; cp1++) { 99 line[8] = *cp1; 100 for (cp = cp2 = TTY_OLD_SUFFIX TTY_NEW_SUFFIX; *cp2; cp2++) { 101 line[5] = 'p'; 102 line[9] = *cp2; 103 if ((master = open(line, O_RDWR, 0)) == -1) { 104 if (errno != ENOENT) 105 continue; /* busy */ 106 if (cp2 - cp + 1 < sizeof(TTY_OLD_SUFFIX)) 107 return -1; /* out of ptys */ 108 else 109 break; /* out of ptys in this group */ 110 } 111 line[5] = 't'; 112 linep = line; 113 if (chown(line, getuid(), ttygid) == 0 && 114 chmod(line, mode) == 0 && 115 revoke(line) == 0 && 116 (slave = open(line, O_RDWR, 0)) != -1) { 117 gotit: 118 *amaster = master; 119 *aslave = slave; 120 if (name) 121 (void)strcpy(name, linep); 122 if (term) 123 (void)tcsetattr(slave, TCSAFLUSH, term); 124 if (winp) 125 (void)ioctl(slave, TIOCSWINSZ, winp); 126 return 0; 127 } 128 (void)close(master); 129 } 130 } 131 errno = ENOENT; /* out of ptys */ 132 return -1; 133 } 134 135 pid_t 136 forkpty(int *amaster, char *name, struct termios *term, struct winsize *winp) 137 { 138 int master, slave; 139 pid_t pid; 140 141 _DIAGASSERT(amaster != NULL); 142 /* name may be NULL */ 143 /* term may be NULL */ 144 /* winp may be NULL */ 145 146 if (openpty(&master, &slave, name, term, winp) == -1) 147 return -1; 148 switch (pid = fork()) { 149 case -1: 150 return -1; 151 case 0: 152 /* 153 * child 154 */ 155 (void)close(master); 156 login_tty(slave); 157 return 0; 158 } 159 /* 160 * parent 161 */ 162 *amaster = master; 163 (void)close(slave); 164 return pid; 165 } 166