1 /* $NetBSD: pty.c,v 1.31 2009/02/20 16:44:06 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 1.31 2009/02/20 16:44:06 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 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 grs, *grp; 72 char grbuf[1024]; 73 74 _DIAGASSERT(amaster != NULL); 75 _DIAGASSERT(aslave != NULL); 76 /* name may be NULL */ 77 /* term may be NULL */ 78 /* winp may be NULL */ 79 80 if ((master = open("/dev/ptm", O_RDWR)) != -1) { 81 struct ptmget pt; 82 if (ioctl(master, TIOCPTMGET, &pt) != -1) { 83 (void)close(master); 84 master = pt.cfd; 85 slave = pt.sfd; 86 linep = pt.sn; 87 goto gotit; 88 } 89 (void)close(master); 90 } 91 92 (void)getgrnam_r("tty", &grs, grbuf, sizeof(grbuf), &grp); 93 if (grp != NULL) { 94 ttygid = grp->gr_gid; 95 mode = S_IRUSR|S_IWUSR|S_IWGRP; 96 } else { 97 ttygid = getgid(); 98 mode = S_IRUSR|S_IWUSR; 99 } 100 101 for (cp1 = TTY_LETTERS; *cp1; cp1++) { 102 line[8] = *cp1; 103 for (cp = cp2 = TTY_OLD_SUFFIX TTY_NEW_SUFFIX; *cp2; cp2++) { 104 line[5] = 'p'; 105 line[9] = *cp2; 106 if ((master = open(line, O_RDWR, 0)) == -1) { 107 if (errno != ENOENT) 108 continue; /* busy */ 109 if ((size_t)(cp2 - cp + 1) < sizeof(TTY_OLD_SUFFIX)) 110 return -1; /* out of ptys */ 111 else 112 break; /* out of ptys in this group */ 113 } 114 line[5] = 't'; 115 linep = line; 116 if (chown(line, getuid(), ttygid) == 0 && 117 chmod(line, mode) == 0 && 118 revoke(line) == 0 && 119 (slave = open(line, O_RDWR, 0)) != -1) { 120 gotit: 121 *amaster = master; 122 *aslave = slave; 123 if (name) 124 (void)strcpy(name, linep); 125 if (term) 126 (void)tcsetattr(slave, TCSAFLUSH, term); 127 if (winp) 128 (void)ioctl(slave, TIOCSWINSZ, winp); 129 return 0; 130 } 131 (void)close(master); 132 } 133 } 134 errno = ENOENT; /* out of ptys */ 135 return -1; 136 } 137 138 pid_t 139 forkpty(int *amaster, char *name, struct termios *term, struct winsize *winp) 140 { 141 int master, slave; 142 pid_t pid; 143 144 _DIAGASSERT(amaster != NULL); 145 /* name may be NULL */ 146 /* term may be NULL */ 147 /* winp may be NULL */ 148 149 if (openpty(&master, &slave, name, term, winp) == -1) 150 return -1; 151 switch (pid = fork()) { 152 case -1: 153 return -1; 154 case 0: 155 /* 156 * child 157 */ 158 (void)close(master); 159 login_tty(slave); 160 return 0; 161 } 162 /* 163 * parent 164 */ 165 *amaster = master; 166 (void)close(slave); 167 return pid; 168 } 169