1/* 2 * Please note: this implementation of openpty() is far from complete. 3 * it is just enough for portable OpenSSH's needs. 4 */ 5 6/* 7 * Copyright (c) 2004 Damien Miller <djm@mindrot.org> 8 * 9 * Permission to use, copy, modify, and distribute this software for any 10 * purpose with or without fee is hereby granted, provided that the above 11 * copyright notice and this permission notice appear in all copies. 12 * 13 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 14 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 15 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 16 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 17 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 18 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 19 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 20 */ 21 22/* 23 * Author: Tatu Ylonen <ylo@cs.hut.fi> 24 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 25 * All rights reserved 26 * Allocating a pseudo-terminal, and making it the controlling tty. 27 * 28 * As far as I am concerned, the code I have written for this software 29 * can be used freely for any purpose. Any derived versions of this 30 * software must be clearly marked as such, and if the derived work is 31 * incompatible with the protocol description in the RFC file, it must be 32 * called by a name other than "ssh" or "Secure Shell". 33 */ 34 35#include "includes.h" 36#if !defined(HAVE_OPENPTY) 37 38#include <sys/types.h> 39 40#include <stdlib.h> 41 42#ifdef HAVE_SYS_STAT_H 43# include <sys/stat.h> 44#endif 45#ifdef HAVE_SYS_IOCTL_H 46# include <sys/ioctl.h> 47#endif 48 49#ifdef HAVE_FCNTL_H 50# include <fcntl.h> 51#endif 52 53#ifdef HAVE_UTIL_H 54# include <util.h> 55#endif /* HAVE_UTIL_H */ 56 57#ifdef HAVE_PTY_H 58# include <pty.h> 59#endif 60#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H) 61# include <sys/stropts.h> 62#endif 63 64#include <signal.h> 65#include <string.h> 66#include <unistd.h> 67 68#include "misc.h" 69#include "log.h" 70 71#ifndef O_NOCTTY 72#define O_NOCTTY 0 73#endif 74 75#if defined(HAVE_DEV_PTMX) && !defined(HAVE__GETPTY) 76static int 77openpty_streams(int *amaster, int *aslave) 78{ 79 /* 80 * This code is used e.g. on Solaris 2.x. (Note that Solaris 2.3 81 * also has bsd-style ptys, but they simply do not work.) 82 */ 83 int ptm; 84 char *pts; 85 sshsig_t old_signal; 86 87 if ((ptm = open("/dev/ptmx", O_RDWR | O_NOCTTY)) == -1) 88 return (-1); 89 90 /* XXX: need to close ptm on error? */ 91 old_signal = ssh_signal(SIGCHLD, SIG_DFL); 92 if (grantpt(ptm) < 0) 93 return (-1); 94 ssh_signal(SIGCHLD, old_signal); 95 96 if (unlockpt(ptm) < 0) 97 return (-1); 98 99 if ((pts = ptsname(ptm)) == NULL) 100 return (-1); 101 *amaster = ptm; 102 103 /* Open the slave side. */ 104 if ((*aslave = open(pts, O_RDWR | O_NOCTTY)) == -1) { 105 close(*amaster); 106 return (-1); 107 } 108 109# if defined(I_FIND) && defined(__SVR4) 110 /* 111 * If the streams modules have already been pushed then there 112 * is no more work to do here. 113 */ 114 if (ioctl(*aslave, I_FIND, "ptem") != 0) 115 return 0; 116# endif 117 118 /* 119 * Try to push the appropriate streams modules, as described 120 * in Solaris pts(7). 121 */ 122 ioctl(*aslave, I_PUSH, "ptem"); 123 ioctl(*aslave, I_PUSH, "ldterm"); 124# ifndef __hpux 125 ioctl(*aslave, I_PUSH, "ttcompat"); 126# endif /* __hpux */ 127 return (0); 128} 129#endif 130 131int 132openpty(int *amaster, int *aslave, char *name, struct termios *termp, 133 struct winsize *winp) 134{ 135#if defined(HAVE__GETPTY) 136 /* 137 * _getpty(3) exists in SGI Irix 4.x, 5.x & 6.x -- it generates more 138 * pty's automagically when needed 139 */ 140 char *slave; 141 142 if ((slave = _getpty(amaster, O_RDWR, 0622, 0)) == NULL) 143 return (-1); 144 145 /* Open the slave side. */ 146 if ((*aslave = open(slave, O_RDWR | O_NOCTTY)) == -1) { 147 close(*amaster); 148 return (-1); 149 } 150 return (0); 151 152#elif defined(HAVE_DEV_PTMX) 153 154#ifdef SSHD_ACQUIRES_CTTY 155 /* 156 * On some (most? all?) SysV based systems with STREAMS based terminals, 157 * sshd will acquire a controlling terminal when it pushes the "ptem" 158 * module. On such platforms, first allocate a sacrificial pty so 159 * that sshd already has a controlling terminal before allocating the 160 * one that will be passed back to the user process. This ensures 161 * the second pty is not already the controlling terminal for a 162 * different session and is available to become controlling terminal 163 * for the client's subprocess. See bugzilla #245 for details. 164 */ 165 int r, fd; 166 static int junk_ptyfd = -1, junk_ttyfd; 167 168 r = openpty_streams(amaster, aslave); 169 if (junk_ptyfd == -1 && (fd = open(_PATH_TTY, O_RDWR|O_NOCTTY)) >= 0) { 170 close(fd); 171 junk_ptyfd = *amaster; 172 junk_ttyfd = *aslave; 173 debug("STREAMS bug workaround pty %d tty %d name %s", 174 junk_ptyfd, junk_ttyfd, ttyname(junk_ttyfd)); 175 } else 176 return r; 177#endif 178 179 return openpty_streams(amaster, aslave); 180 181#elif defined(HAVE_DEV_PTS_AND_PTC) 182 /* AIX-style pty code. */ 183 const char *ttname; 184 185 if ((*amaster = open("/dev/ptc", O_RDWR | O_NOCTTY)) == -1) 186 return (-1); 187 if ((ttname = ttyname(*amaster)) == NULL) 188 return (-1); 189 if ((*aslave = open(ttname, O_RDWR | O_NOCTTY)) == -1) { 190 close(*amaster); 191 return (-1); 192 } 193 return (0); 194 195#else 196 /* BSD-style pty code. */ 197 char ptbuf[64], ttbuf[64]; 198 int i; 199 const char *ptymajors = "pqrstuvwxyzabcdefghijklmno" 200 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; 201 const char *ptyminors = "0123456789abcdef"; 202 int num_minors = strlen(ptyminors); 203 int num_ptys = strlen(ptymajors) * num_minors; 204 struct termios tio; 205 206 for (i = 0; i < num_ptys; i++) { 207 snprintf(ptbuf, sizeof(ptbuf), "/dev/pty%c%c", 208 ptymajors[i / num_minors], ptyminors[i % num_minors]); 209 snprintf(ttbuf, sizeof(ttbuf), "/dev/tty%c%c", 210 ptymajors[i / num_minors], ptyminors[i % num_minors]); 211 212 if ((*amaster = open(ptbuf, O_RDWR | O_NOCTTY)) == -1) { 213 /* Try SCO style naming */ 214 snprintf(ptbuf, sizeof(ptbuf), "/dev/ptyp%d", i); 215 snprintf(ttbuf, sizeof(ttbuf), "/dev/ttyp%d", i); 216 if ((*amaster = open(ptbuf, O_RDWR | O_NOCTTY)) == -1) 217 continue; 218 } 219 220 /* Open the slave side. */ 221 if ((*aslave = open(ttbuf, O_RDWR | O_NOCTTY)) == -1) { 222 close(*amaster); 223 return (-1); 224 } 225 /* set tty modes to a sane state for broken clients */ 226 if (tcgetattr(*amaster, &tio) != -1) { 227 tio.c_lflag |= (ECHO | ISIG | ICANON); 228 tio.c_oflag |= (OPOST | ONLCR); 229 tio.c_iflag |= ICRNL; 230 tcsetattr(*amaster, TCSANOW, &tio); 231 } 232 233 return (0); 234 } 235 return (-1); 236#endif 237} 238 239#endif /* !defined(HAVE_OPENPTY) */ 240 241