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 #if defined(__minix) 46 #include <stdlib.h> 47 #endif /* defined(__minix) */ 48 #include <assert.h> 49 #include <errno.h> 50 #include <fcntl.h> 51 #include <grp.h> 52 #include <stdio.h> 53 #include <string.h> 54 #include <termios.h> 55 #include <unistd.h> 56 #include <util.h> 57 58 /* 59 * XXX: `v' removed until no ports are using console devices which use ttyv0 60 */ 61 #define TTY_LETTERS "pqrstuwxyzPQRST" 62 #define TTY_OLD_SUFFIX "0123456789abcdef" 63 #define TTY_NEW_SUFFIX "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" 64 65 int 66 openpty(int *amaster, int *aslave, char *name, struct termios *term, 67 struct winsize *winp) 68 { 69 char line[] = "/dev/XtyXX"; 70 const char *cp1, *cp2, *cp, *linep; 71 int master, slave; 72 gid_t ttygid; 73 mode_t mode; 74 struct group grs, *grp; 75 char grbuf[1024]; 76 77 _DIAGASSERT(amaster != NULL); 78 _DIAGASSERT(aslave != NULL); 79 /* name may be NULL */ 80 /* term may be NULL */ 81 /* winp may be NULL */ 82 83 #if !defined(__minix) 84 if ((master = open("/dev/ptm", O_RDWR)) != -1) { 85 struct ptmget pt; 86 if (ioctl(master, TIOCPTMGET, &pt) != -1) { 87 (void)close(master); 88 master = pt.cfd; 89 slave = pt.sfd; 90 linep = pt.sn; 91 goto gotit; 92 } 93 (void)close(master); 94 } 95 #else 96 /* 97 * On MINIX3, we implement non-root openpty(3) using Unix98 PTYs. 98 * If this fails, the fallback code below works for root only. 99 */ 100 if ((master = posix_openpt(O_RDWR | O_NOCTTY)) != -1) { 101 if (grantpt(master) != -1 && unlockpt(master) != -1 && 102 (linep = ptsname(master)) != NULL && 103 (slave = open(linep, O_RDWR | O_NOCTTY)) != -1) 104 goto gotit; 105 (void)close(master); 106 } 107 #endif /* !defined(__minix) */ 108 109 (void)getgrnam_r("tty", &grs, grbuf, sizeof(grbuf), &grp); 110 if (grp != NULL) { 111 ttygid = grp->gr_gid; 112 mode = S_IRUSR|S_IWUSR|S_IWGRP; 113 } else { 114 ttygid = getgid(); 115 mode = S_IRUSR|S_IWUSR; 116 } 117 118 for (cp1 = TTY_LETTERS; *cp1; cp1++) { 119 line[8] = *cp1; 120 for (cp = cp2 = TTY_OLD_SUFFIX TTY_NEW_SUFFIX; *cp2; cp2++) { 121 line[5] = 'p'; 122 line[9] = *cp2; 123 #if defined(__minix) 124 if ((master = open(line, O_RDWR | O_NOCTTY, 0)) == -1) { 125 #else 126 if ((master = open(line, O_RDWR, 0)) == -1) { 127 #endif /* defined(__minix) */ 128 if (errno != ENOENT) 129 continue; /* busy */ 130 if ((size_t)(cp2 - cp + 1) < sizeof(TTY_OLD_SUFFIX)) 131 return -1; /* out of ptys */ 132 else 133 break; /* out of ptys in this group */ 134 } 135 line[5] = 't'; 136 linep = line; 137 if (chown(line, getuid(), ttygid) == 0 && 138 chmod(line, mode) == 0 && 139 #if !defined(__minix) 140 revoke(line) == 0 && 141 #endif /* !defined(__minix) */ 142 #if defined(__minix) 143 (slave = open(line, O_RDWR | O_NOCTTY, 0)) != -1) { 144 #else 145 (slave = open(line, O_RDWR, 0)) != -1) { 146 #endif /* defined(__minix) */ 147 gotit: 148 *amaster = master; 149 *aslave = slave; 150 if (name) 151 (void)strcpy(name, linep); 152 if (term) 153 (void)tcsetattr(slave, TCSAFLUSH, term); 154 if (winp) 155 (void)ioctl(slave, TIOCSWINSZ, winp); 156 return 0; 157 } 158 (void)close(master); 159 } 160 } 161 errno = ENOENT; /* out of ptys */ 162 return -1; 163 } 164 165 pid_t 166 forkpty(int *amaster, char *name, struct termios *term, struct winsize *winp) 167 { 168 int master, slave; 169 pid_t pid; 170 171 _DIAGASSERT(amaster != NULL); 172 /* name may be NULL */ 173 /* term may be NULL */ 174 /* winp may be NULL */ 175 176 if (openpty(&master, &slave, name, term, winp) == -1) 177 return -1; 178 switch (pid = fork()) { 179 case -1: 180 return -1; 181 case 0: 182 /* 183 * child 184 */ 185 (void)close(master); 186 login_tty(slave); 187 return 0; 188 } 189 /* 190 * parent 191 */ 192 *amaster = master; 193 (void)close(slave); 194 return pid; 195 } 196