2 * childio.c -- set up communication with child processes
4 * Copyright 1991 by Digital Equipment Corporation, Maynard,
5 * Massachusetts. Enhancements Copyright
6 * 1992-2001,2002,2003,2004,2005,2006,2007,2008,2009 Free Software
9 * The following terms apply to Digital Equipment Corporation's copyright
11 * ------------------------------------------------------------------------
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15 * documentation for any purpose and without fee is hereby granted,
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20 * software without specific, written prior permission.
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23 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
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26 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
27 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
29 * ------------------------------------------------------------------------
31 * The following terms apply to the enhanced version of XBoard
32 * distributed by the Free Software Foundation:
33 * ------------------------------------------------------------------------
35 * GNU XBoard is free software: you can redistribute it and/or modify
36 * it under the terms of the GNU General Public License as published by
37 * the Free Software Foundation, either version 3 of the License, or (at
38 * your option) any later version.
40 * GNU XBoard is distributed in the hope that it will be useful, but
41 * WITHOUT ANY WARRANTY; without even the implied warranty of
42 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
43 * General Public License for more details.
45 * You should have received a copy of the GNU General Public License
46 * along with this program. If not, see http://www.gnu.org/licenses/. *
48 *------------------------------------------------------------------------
49 ** See the file ChangeLog for a revision history. */
51 /* This file splits into two entirely different pieces of code
52 depending on whether USE_PTYS is 1. The whole reason for all
53 the pty nonsense is that select() does not work on pipes in System-V
54 derivatives (at least some of them). This is a problem because
55 XtAppAddInput works by adding its argument to a select that is done
70 /* This code is for systems where pipes work properly */
72 void SetUpChildIO(to_prog, from_prog)
73 int to_prog[2], from_prog[2];
75 signal(SIGPIPE, SIG_IGN);
80 #else /* USE_PTYS == 1 */
81 /* This code is for all systems where we must use ptys */
85 #include <sys/ioctl.h>
88 #endif /* HAVE_STROPTS_H */
90 # include <sys/fcntl.h>
91 #else /* not HAVE_SYS_FCNTL_H */
94 # endif /* HAVE_FCNTL_H */
95 #endif /* not HAVE_SYS_FCNTL_H */
97 int PseudoTTY P((char pty_name[]));
99 int SetUpChildIO(to_prog, from_prog)
100 int to_prog[2], from_prog[2];
102 char pty_name[MSG_SIZ];
104 if ((to_prog[1] = PseudoTTY(pty_name)) == -1) {
105 DisplayFatalError("Can't open pseudo-tty", errno, 1);
108 from_prog[0] = to_prog[1];
109 to_prog[0] = from_prog[1] = open(pty_name, O_RDWR, 0);
111 #if HAVE_STROPTS_H /* do we really need this?? pipe-like behavior is fine */
112 if (ioctl (to_prog[0], I_PUSH, "ptem") == -1 ||
113 ioctl (to_prog[0], I_PUSH, "ldterm") == -1 ||
114 ioctl (to_prog[0], I_PUSH, "ttcompat") == -1) {
115 # ifdef NOTDEF /* seems some systems don't have or need ptem and ttcompat */
116 DisplayFatalError("Can't ioctl pseudo-tty", errno, 1);
120 #endif /* HAVE_STROPTS_H */
125 /* This code is for SVR4 */
127 int PseudoTTY(pty_name)
130 extern char *ptsname();
134 fd = open("/dev/ptmx", O_RDWR);
135 if (fd < 0) return fd;
136 if (grantpt(fd) == -1) return -1;
137 if (unlockpt(fd) == -1) return -1;
138 if (!(ptss = ptsname(fd))) return -1;
139 strcpy(pty_name, ptss);
143 #else /* not HAVE_GRANTPT */
145 /* This code is for IRIX */
147 int PseudoTTY(pty_name)
153 ptyn = _getpty(&fd, O_RDWR, 0600, 0);
154 if (ptyn == NULL) return -1;
155 strcpy(pty_name, ptyn);
159 #else /* not HAVE__GETPTY */
161 /* This code is for Sequent DYNIX/ptx. Untested. --tpm */
163 int PseudoTTY(pty_name)
167 char *slave, *master;
169 fd = getpseudotty(&slave, &master);
170 if (fd < 0) return fd;
171 strcpy(pty_name, slave);
175 #else /* not HAVE_LIBSEQ */
176 /* This code is for all other systems */
177 /* The code is adapted from GNU Emacs 19.24 */
179 #ifndef FIRST_PTY_LETTER
180 #define FIRST_PTY_LETTER 'p'
182 #ifndef LAST_PTY_LETTER
183 #define LAST_PTY_LETTER 'z'
186 int PseudoTTY(pty_name)
193 /* Some systems name their pseudoterminals so that there are gaps in
194 the usual sequence - for example, on HP9000/S700 systems, there
195 are no pseudoterminals with names ending in 'f'. So we wait for
196 three failures in a row before deciding that we've reached the
198 int failed_count = 0;
203 for (c = FIRST_PTY_LETTER; c <= LAST_PTY_LETTER; c++)
204 for (i = 0; i < 16; i++)
207 #ifdef PTY_NAME_SPRINTF
210 sprintf (pty_name, "/dev/pty%c%x", c, i);
211 #endif /* no PTY_NAME_SPRINTF */
215 #else /* no PTY_OPEN */
216 if (stat (pty_name, &stb) < 0)
219 if (failed_count >= 3)
224 fd = open (pty_name, O_RDWR, 0);
225 #endif /* no PTY_OPEN */
229 /* check to make certain that both sides are available
230 this avoids a nasty yet stupid bug in rlogins */
231 #ifdef PTY_TTY_NAME_SPRINTF
234 sprintf (pty_name, "/dev/tty%c%x", c, i);
235 #endif /* no PTY_TTY_NAME_SPRINTF */
237 if (access (pty_name, 6) != 0)
242 #endif /* not UNIPLUS */
244 /* On AIX, the parent gets SIGHUP when a pty attached
245 child dies. So, we ignore SIGHUP once we've started
246 a child on a pty. Note that this may cause xboard
247 not to die when it should, i.e., when its own
248 controlling tty goes away.
250 signal(SIGHUP, SIG_IGN);
251 #endif /* IBMRTAIX */
258 #endif /* not HAVE_LIBSEQ */
259 #endif /* not HAVE__GETPTY */
260 #endif /* not HAVE_GRANTPT */
261 #endif /* USE_PTYS */