1 /* $OpenBSD: pty.c,v 1.21 2017/04/20 17:48:30 nicm Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 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/types.h> 33 #include <sys/stat.h> 34 #include <sys/ioctl.h> 35 #include <fcntl.h> 36 #include <termios.h> 37 #include <errno.h> 38 #include <unistd.h> 39 #include <stdio.h> 40 #include <string.h> 41 #include <grp.h> 42 #include <sys/tty.h> 43 44 #include "util.h" 45 46 int 47 getptmfd(void) 48 { 49 return (open(PATH_PTMDEV, O_RDWR|O_CLOEXEC)); 50 } 51 52 int 53 openpty(int *amaster, int *aslave, char *name, struct termios *termp, 54 struct winsize *winp) 55 { 56 int ptmfd; 57 58 if ((ptmfd = getptmfd()) == -1) 59 return (-1); 60 if (fdopenpty(ptmfd, amaster, aslave, name, termp, winp) == -1) { 61 close(ptmfd); 62 return (-1); 63 } 64 close(ptmfd); 65 return (0); 66 } 67 68 int 69 fdopenpty(int ptmfd, int *amaster, int *aslave, char *name, 70 struct termios *termp, struct winsize *winp) 71 { 72 int master, slave; 73 struct ptmget ptm; 74 75 /* 76 * Use /dev/ptm and the PTMGET ioctl to get a properly set up and 77 * owned pty/tty pair. 78 */ 79 if (ioctl(ptmfd, PTMGET, &ptm) == -1) 80 return (-1); 81 82 master = ptm.cfd; 83 slave = ptm.sfd; 84 if (name) { 85 /* 86 * Manual page says "at least 16 characters". 87 */ 88 strlcpy(name, ptm.sn, 16); 89 } 90 *amaster = master; 91 *aslave = slave; 92 if (termp) 93 (void) tcsetattr(slave, TCSAFLUSH, termp); 94 if (winp) 95 (void) ioctl(slave, TIOCSWINSZ, winp); 96 return (0); 97 } 98 99 pid_t 100 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp) 101 { 102 int ptmfd; 103 pid_t pid; 104 105 if ((ptmfd = getptmfd()) == -1) 106 return (-1); 107 if ((pid = fdforkpty(ptmfd, amaster, name, termp, winp)) == -1) { 108 close(ptmfd); 109 return (-1); 110 } 111 close(ptmfd); 112 return (pid); 113 } 114 115 pid_t 116 fdforkpty(int ptmfd, int *amaster, char *name, struct termios *termp, 117 struct winsize *winp) 118 { 119 int master, slave; 120 pid_t pid; 121 122 if (fdopenpty(ptmfd, &master, &slave, name, termp, winp) == -1) 123 return (-1); 124 switch (pid = fork()) { 125 case -1: 126 (void) close(master); 127 (void) close(slave); 128 return (-1); 129 case 0: 130 /* 131 * child 132 */ 133 (void) close(master); 134 login_tty(slave); 135 return (0); 136 } 137 /* 138 * parent 139 */ 140 *amaster = master; 141 (void) close(slave); 142 return (pid); 143 } 144