2 * childio.c -- set up communication with child processes
4 * Copyright 1991 by Digital Equipment Corporation, Maynard,
7 * Enhancements Copyright 1992-2001, 2002, 2003, 2004, 2005, 2006,
8 * 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 Free Software Foundation, Inc.
10 * The following terms apply to Digital Equipment Corporation's copyright
12 * ------------------------------------------------------------------------
15 * Permission to use, copy, modify, and distribute this software and its
16 * documentation for any purpose and without fee is hereby granted,
17 * provided that the above copyright notice appear in all copies and that
18 * both that copyright notice and this permission notice appear in
19 * supporting documentation, and that the name of Digital not be
20 * used in advertising or publicity pertaining to distribution of the
21 * software without specific, written prior permission.
23 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
24 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
25 * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
26 * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
27 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
28 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
30 * ------------------------------------------------------------------------
32 * The following terms apply to the enhanced version of XBoard
33 * distributed by the Free Software Foundation:
34 * ------------------------------------------------------------------------
36 * GNU XBoard is free software: you can redistribute it and/or modify
37 * it under the terms of the GNU General Public License as published by
38 * the Free Software Foundation, either version 3 of the License, or (at
39 * your option) any later version.
41 * GNU XBoard is distributed in the hope that it will be useful, but
42 * WITHOUT ANY WARRANTY; without even the implied warranty of
43 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
44 * General Public License for more details.
46 * You should have received a copy of the GNU General Public License
47 * along with this program. If not, see http://www.gnu.org/licenses/. *
49 *------------------------------------------------------------------------
50 ** See the file ChangeLog for a revision history. */
52 /* This file splits into two entirely different pieces of code
53 depending on whether USE_PTYS is 1. The whole reason for all
54 the pty nonsense is that select() does not work on pipes in System-V
55 derivatives (at least some of them). This is a problem because
56 XtAppAddInput works by adding its argument to a select that is done
70 #include "backend.h" /* for safeStrCpy */
73 /* This code is for systems where pipes work properly */
76 SetUpChildIO (int to_prog[2], int from_prog[2])
78 signal(SIGPIPE, SIG_IGN);
83 #else /* USE_PTYS == 1 */
84 /* This code is for all systems where we must use ptys */
88 #include <sys/ioctl.h>
91 #endif /* HAVE_STROPTS_H */
93 # include <sys/fcntl.h>
94 #else /* not HAVE_SYS_FCNTL_H */
97 # endif /* HAVE_FCNTL_H */
98 #endif /* not HAVE_SYS_FCNTL_H */
100 int PseudoTTY P((char pty_name[]));
103 SetUpChildIO (int to_prog[2], int from_prog[2])
105 char pty_name[MSG_SIZ];
107 if ((to_prog[1] = PseudoTTY(pty_name)) == -1) {
108 DisplayFatalError("Can't open pseudo-tty", errno, 1);
111 from_prog[0] = to_prog[1];
112 to_prog[0] = from_prog[1] = open(pty_name, O_RDWR, 0);
114 #if HAVE_STROPTS_H /* do we really need this?? pipe-like behavior is fine */
115 if (ioctl (to_prog[0], I_PUSH, "ptem") == -1 ||
116 ioctl (to_prog[0], I_PUSH, "ldterm") == -1 ||
117 ioctl (to_prog[0], I_PUSH, "ttcompat") == -1) {
118 # ifdef NOTDEF /* seems some systems don't have or need ptem and ttcompat */
119 DisplayFatalError("Can't ioctl pseudo-tty", errno, 1);
123 #endif /* HAVE_STROPTS_H */
128 /* This code is for SVR4 */
131 PseudoTTY (char pty_name[])
133 extern char *ptsname();
137 fd = open("/dev/ptmx", O_RDWR);
138 if (fd < 0) return fd;
139 if (grantpt(fd) == -1) return -1;
140 if (unlockpt(fd) == -1) return -1;
141 if (!(ptss = ptsname(fd))) return -1;
142 safeStrCpy(pty_name, ptss, sizeof(pty_name)/sizeof(pty_name[0]));
146 #else /* not HAVE_GRANTPT */
148 /* This code is for IRIX */
151 PseudoTTY (char pty_name[])
156 ptyn = _getpty(&fd, O_RDWR, 0600, 0);
157 if (ptyn == NULL) return -1;
158 safeStrCpy(pty_name, ptyn, sizeof(pty_name)/sizeof(pty_name[0]));
162 #else /* not HAVE__GETPTY */
164 /* This code is for Sequent DYNIX/ptx. Untested. --tpm */
167 PseudoTTY (char pty_name[])
170 char *slave, *master;
172 fd = getpseudotty(&slave, &master);
173 if (fd < 0) return fd;
174 safeStrCpy(pty_name, slave, sizeof(pty_name)/sizeof(pty_name[0]));
178 #else /* not HAVE_LIBSEQ */
179 /* This code is for all other systems */
180 /* The code is adapted from GNU Emacs 19.24 */
182 #ifndef FIRST_PTY_LETTER
183 #define FIRST_PTY_LETTER 'p'
185 #ifndef LAST_PTY_LETTER
186 #define LAST_PTY_LETTER 'z'
190 PseudoTTY (char pty_name[])
196 /* Some systems name their pseudoterminals so that there are gaps in
197 the usual sequence - for example, on HP9000/S700 systems, there
198 are no pseudoterminals with names ending in 'f'. So we wait for
199 three failures in a row before deciding that we've reached the
201 int failed_count = 0;
206 for (c = FIRST_PTY_LETTER; c <= LAST_PTY_LETTER; c++)
207 for (i = 0; i < 16; i++)
210 #ifdef PTY_NAME_SPRINTF
213 sprintf (pty_name, "/dev/pty%c%x", c, i);
214 #endif /* no PTY_NAME_SPRINTF */
218 #else /* no PTY_OPEN */
219 if (stat (pty_name, &stb) < 0)
222 if (failed_count >= 3)
227 fd = open (pty_name, O_RDWR, 0);
228 #endif /* no PTY_OPEN */
232 /* check to make certain that both sides are available
233 this avoids a nasty yet stupid bug in rlogins */
234 #ifdef PTY_TTY_NAME_SPRINTF
237 sprintf (pty_name, "/dev/tty%c%x", c, i);
238 #endif /* no PTY_TTY_NAME_SPRINTF */
240 if (access (pty_name, 6) != 0)
245 #endif /* not UNIPLUS */
247 /* On AIX, the parent gets SIGHUP when a pty attached
248 child dies. So, we ignore SIGHUP once we've started
249 a child on a pty. Note that this may cause xboard
250 not to die when it should, i.e., when its own
251 controlling tty goes away.
253 signal(SIGHUP, SIG_IGN);
254 #endif /* IBMRTAIX */
261 #endif /* not HAVE_LIBSEQ */
262 #endif /* not HAVE__GETPTY */
263 #endif /* not HAVE_GRANTPT */
264 #endif /* USE_PTYS */