xref: /freebsd/contrib/tcsh/sh.sem.c (revision c98323078dede7579020518ec84cdcb478e5c142)
1 /* $Header: /src/pub/tcsh/sh.sem.c,v 3.60 2004/02/23 15:04:36 christos Exp $ */
2 /*
3  * sh.sem.c: I/O redirections and job forking. A touchy issue!
4  *	     Most stuff with builtins is incorrect
5  */
6 /*-
7  * Copyright (c) 1980, 1991 The Regents of the University of California.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 #include "sh.h"
35 
36 RCSID("$Id: sh.sem.c,v 3.60 2004/02/23 15:04:36 christos Exp $")
37 
38 #include "tc.h"
39 #include "tw.h"
40 #ifdef WINNT_NATIVE
41 #include "nt.const.h"
42 #endif /*WINNT_NATIVE*/
43 
44 #ifdef CLOSE_ON_EXEC
45 # ifndef SUNOS4
46 #  ifndef CLEX_DUPS
47 #   define CLEX_DUPS
48 #  endif /* CLEX_DUPS */
49 # endif /* !SUNOS4 */
50 #endif /* CLOSE_ON_EXEC */
51 
52 #if defined(__sparc__) || defined(sparc)
53 # if !defined(MACH) && SYSVREL == 0 && !defined(Lynx) && !defined(BSD4_4) && !defined(linux)
54 #  include <vfork.h>
55 # endif /* !MACH && SYSVREL == 0 && !Lynx && !BSD4_4 && !linux */
56 #endif /* __sparc__ || sparc */
57 
58 #ifdef VFORK
59 static	sigret_t	vffree	__P((int));
60 #endif
61 static	Char		*splicepipe	__P((struct command *, Char *));
62 static	void		 doio		__P((struct command *, int *, int *));
63 static	void		 chkclob	__P((char *));
64 
65 /*
66  * C shell
67  */
68 
69 /*
70  * For SVR4, there are problems with pipelines having the first process as
71  * the group leader.  The problem occurs when the first process exits before
72  * the others have a chance to setpgid().  This is because in SVR4 you can't
73  * have a zombie as a group leader.  The solution I have used is to reverse
74  * the order in which pipelines are started, making the last process the
75  * group leader.  (Note I am not using 'pipeline' in the generic sense -- I
76  * mean processes connected by '|'.)  I don't know yet if this causes other
77  * problems.
78  *
79  * All the changes for this are in execute(), and are enclosed in
80  * '#ifdef BACKPIPE'
81  *
82  * David Dawes (dawes@physics.su.oz.au) Oct 1991
83  */
84 
85 /*VARARGS 1*/
86 void
87 execute(t, wanttty, pipein, pipeout, do_glob)
88     register struct command *t;
89     int     wanttty;
90     int *pipein, *pipeout;
91     bool do_glob;
92 {
93 #ifdef VFORK
94     extern bool use_fork;	/* use fork() instead of vfork()? */
95 #endif
96 
97     bool    forked = 0;
98     struct biltins *bifunc;
99     int     pid = 0;
100     int     pv[2];
101 #ifdef BSDSIGS
102     static sigmask_t csigmask;
103 #endif /* BSDSIGS */
104 #ifdef VFORK
105     static int onosigchld = 0;
106 #endif /* VFORK */
107     static int nosigchld = 0;
108 
109     (void) &wanttty;
110     (void) &forked;
111     (void) &bifunc;
112 
113     if (t == 0)
114 	return;
115 
116 #ifdef WINNT_NATIVE
117     {
118         if ((varval(STRNTslowexec) == STRNULL) &&
119             !t->t_dcdr && !t->t_dcar && !t->t_dflg && !didfds &&
120             (intty || intact) && (t->t_dtyp == NODE_COMMAND) &&
121 	    !isbfunc(t)) {
122 	    if ((t->t_dcom[0][0] & (QUOTE | TRIM)) == QUOTE)
123 		(void) Strcpy(t->t_dcom[0], t->t_dcom[0] + 1);
124 	    Dfix(t);
125             if (nt_try_fast_exec(t) == 0)
126                 return;
127         }
128     }
129 #endif /* WINNT_NATIVE */
130 
131     /*
132      * Ed hutchins@sgi.com & Dominic dbg@sgi.com
133      * Sat Feb 25 03:13:11 PST 1995
134      * try implicit cd if we have a 1 word command
135      */
136     if (implicit_cd && (intty || intact) && t->t_dcom && t->t_dcom[0] &&
137 	 t->t_dcom[0][0] && (blklen(t->t_dcom) == 1) && !noexec) {
138 	Char sCName[MAXPATHLEN];
139 	Char *pCN;
140 	struct stat stbuf;
141 	char *pathname;
142 
143 	dollar(sCName, t->t_dcom[0]);
144 	pCN = sCName;
145 	if (pCN[0] == '~') {
146 	    Char sCPath[MAXPATHLEN];
147 	    Char *pCP = sCPath;
148 
149 	    ++pCN;
150 	    while (*pCN && *pCN != '/')
151 		*pCP++ = *pCN++;
152 	    *pCP = 0;
153 	    if (sCPath[0])
154 		gethdir(sCPath);
155 	    else
156 		(void) Strcpy(sCPath, varval(STRhome));
157 	    catn(sCPath, pCN, MAXPATHLEN);
158 	    (void) Strcpy(sCName, sCPath);
159 	}
160 
161 	pathname = short2str(sCName);
162 	/* if this is a dir, tack a "cd" on as the first arg */
163 	if ((stat(pathname, &stbuf) != -1 && S_ISDIR(stbuf.st_mode))
164 #ifdef WINNT_NATIVE
165 	    || (pathname[0] && pathname[1] == ':' && pathname[2] == '\0')
166 #endif /* WINNT_NATIVE */
167 	) {
168 	    Char *vCD[2];
169 	    Char **ot_dcom = t->t_dcom;
170 
171 	    vCD[0] = Strsave(STRcd);
172 	    vCD[1] = NULL;
173 	    t->t_dcom = blkspl(vCD, ot_dcom);
174 	    if (implicit_cd > 1) {
175 		blkpr(t->t_dcom);
176 		xputchar( '\n' );
177 	    }
178 	    xfree((ptr_t) ot_dcom);
179 	}
180     }
181 
182     /*
183      * From: Michael Schroeder <mlschroe@immd4.informatik.uni-erlangen.de>
184      * Don't check for wantty > 0...
185      */
186     if (t->t_dflg & F_AMPERSAND)
187 	wanttty = 0;
188     switch (t->t_dtyp) {
189 
190     case NODE_COMMAND:
191 	if ((t->t_dcom[0][0] & (QUOTE | TRIM)) == QUOTE)
192 	    (void) Strcpy(t->t_dcom[0], t->t_dcom[0] + 1);
193 	if ((t->t_dflg & F_REPEAT) == 0)
194 	    Dfix(t);		/* $ " ' \ */
195 	if (t->t_dcom[0] == 0) {
196 	    return;
197 	}
198 	/*FALLTHROUGH*/
199 
200     case NODE_PAREN:
201 #ifdef BACKPIPE
202 	if (t->t_dflg & F_PIPEIN)
203 	    mypipe(pipein);
204 #else /* !BACKPIPE */
205 	if (t->t_dflg & F_PIPEOUT)
206 	    mypipe(pipeout);
207 #endif /* BACKPIPE */
208 	/*
209 	 * Must do << early so parent will know where input pointer should be.
210 	 * If noexec then this is all we do.
211 	 */
212 	if (t->t_dflg & F_READ) {
213 	    (void) close(0);
214 	    heredoc(t->t_dlef);
215 	    if (noexec)
216 		(void) close(0);
217 	}
218 
219 	set(STRstatus, Strsave(STR0), VAR_READWRITE);
220 
221 	/*
222 	 * This mess is the necessary kludge to handle the prefix builtins:
223 	 * nice, nohup, time.  These commands can also be used by themselves,
224 	 * and this is not handled here. This will also work when loops are
225 	 * parsed.
226 	 */
227 	while (t->t_dtyp == NODE_COMMAND)
228 	    if (eq(t->t_dcom[0], STRnice)) {
229 		if (t->t_dcom[1]) {
230 		    if (strchr("+-", t->t_dcom[1][0])) {
231 			if (t->t_dcom[2]) {
232 			    setname("nice");
233 			    t->t_nice =
234 				getn(t->t_dcom[1]);
235 			    lshift(t->t_dcom, 2);
236 			    t->t_dflg |= F_NICE;
237 			}
238 			else
239 			    break;
240 		    }
241 		    else {
242 			t->t_nice = 4;
243 			lshift(t->t_dcom, 1);
244 			t->t_dflg |= F_NICE;
245 		    }
246 		}
247 		else
248 		    break;
249 	    }
250 	    else if (eq(t->t_dcom[0], STRnohup)) {
251 		if (t->t_dcom[1]) {
252 		    t->t_dflg |= F_NOHUP;
253 		    lshift(t->t_dcom, 1);
254 		}
255 		else
256 		    break;
257 	    }
258 	    else if (eq(t->t_dcom[0], STRhup)) {
259 		if (t->t_dcom[1]) {
260 		    t->t_dflg |= F_HUP;
261 		    lshift(t->t_dcom, 1);
262 		}
263 		else
264 		    break;
265 	    }
266 	    else if (eq(t->t_dcom[0], STRtime)) {
267 		if (t->t_dcom[1]) {
268 		    t->t_dflg |= F_TIME;
269 		    lshift(t->t_dcom, 1);
270 		}
271 		else
272 		    break;
273 	    }
274 #ifdef F_VER
275 	    else if (eq(t->t_dcom[0], STRver))
276 		if (t->t_dcom[1] && t->t_dcom[2]) {
277 		    setname("ver");
278 		    t->t_systype = getv(t->t_dcom[1]);
279 		    lshift(t->t_dcom, 2);
280 		    t->t_dflg |= F_VER;
281 		}
282 		else
283 		    break;
284 #endif  /* F_VER */
285 	    else
286 		break;
287 
288 	/* is it a command */
289 	if (t->t_dtyp == NODE_COMMAND) {
290 	    /*
291 	     * Check if we have a builtin function and remember which one.
292 	     */
293 	    bifunc = isbfunc(t);
294  	    if (noexec && bifunc) {
295 		/*
296 		 * Continue for builtins that are part of the scripting language
297 		 */
298 		if (bifunc->bfunct != (bfunc_t)dobreak	&&
299 		    bifunc->bfunct != (bfunc_t)docontin	&&
300 		    bifunc->bfunct != (bfunc_t)doelse	&&
301 		    bifunc->bfunct != (bfunc_t)doend	&&
302 		    bifunc->bfunct != (bfunc_t)doforeach&&
303 		    bifunc->bfunct != (bfunc_t)dogoto	&&
304 		    bifunc->bfunct != (bfunc_t)doif	&&
305 		    bifunc->bfunct != (bfunc_t)dorepeat	&&
306 		    bifunc->bfunct != (bfunc_t)doswbrk	&&
307 		    bifunc->bfunct != (bfunc_t)doswitch	&&
308 		    bifunc->bfunct != (bfunc_t)dowhile	&&
309 		    bifunc->bfunct != (bfunc_t)dozip)
310 		    break;
311 	    }
312 	}
313 	else {			/* not a command */
314 	    bifunc = NULL;
315 	    if (noexec)
316 		break;
317 	}
318 
319 	/*
320 	 * GrP Executing a command - run jobcmd hook
321 	 * Don't run for builtins
322 	 * Don't run if we're not in a tty
323 	 * Don't run if we're not really executing
324 	 */
325 	if (t->t_dtyp == NODE_COMMAND && !bifunc && !noexec && intty) {
326 	    Char *cmd = unparse(t);
327 	    job_cmd(cmd);
328 	    xfree(cmd);
329 	}
330 
331 	/*
332 	 * We fork only if we are timed, or are not the end of a parenthesized
333 	 * list and not a simple builtin function. Simple meaning one that is
334 	 * not pipedout, niced, nohupped, or &'d. It would be nice(?) to not
335 	 * fork in some of these cases.
336 	 */
337 	/*
338 	 * Prevent forking cd, pushd, popd, chdir cause this will cause the
339 	 * shell not to change dir!
340 	 */
341 #ifdef BACKPIPE
342 	/*
343 	 * Can't have NOFORK for the tail of a pipe - because it is not the
344 	 * last command spawned (even if it is at the end of a parenthesised
345 	 * list).
346 	 */
347 	if (t->t_dflg & F_PIPEIN)
348 	    t->t_dflg &= ~(F_NOFORK);
349 #endif /* BACKPIPE */
350 	if (bifunc && (bifunc->bfunct == (bfunc_t)dochngd ||
351 		       bifunc->bfunct == (bfunc_t)dopushd ||
352 		       bifunc->bfunct == (bfunc_t)dopopd))
353 	    t->t_dflg &= ~(F_NICE);
354 	if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 &&
355 	     (!bifunc || t->t_dflg &
356 	      (F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP | F_HUP)))) ||
357 	/*
358 	 * We have to fork for eval too.
359 	 */
360 	    (bifunc && (t->t_dflg & F_PIPEIN) != 0 &&
361 	     bifunc->bfunct == (bfunc_t)doeval)) {
362 #ifdef VFORK
363 	    if (t->t_dtyp == NODE_PAREN ||
364 		t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc)
365 #endif /* VFORK */
366 	    {
367 		forked++;
368 		/*
369 		 * We need to block SIGCHLD here, so that if the process does
370 		 * not die before we can set the process group
371 		 */
372 		if (wanttty >= 0 && !nosigchld) {
373 #ifdef BSDSIGS
374 		    csigmask = sigblock(sigmask(SIGCHLD));
375 #else /* !BSDSIGS */
376 		    (void) sighold(SIGCHLD);
377 #endif /* BSDSIGS */
378 
379 		    nosigchld = 1;
380 		}
381 
382 		pid = pfork(t, wanttty);
383 		if (pid == 0 && nosigchld) {
384 #ifdef BSDSIGS
385 		    (void) sigsetmask(csigmask);
386 #else /* !BSDSIGS */
387 		    (void) sigrelse(SIGCHLD);
388 #endif /* BSDSIGS */
389 		    nosigchld = 0;
390 		}
391 		else if (pid != 0 && (t->t_dflg & F_AMPERSAND))
392 		    backpid = pid;
393 	    }
394 
395 #ifdef VFORK
396 	    else {
397 		int     ochild, osetintr, ohaderr, odidfds;
398 		int     oSHIN, oSHOUT, oSHDIAG, oOLDSTD, otpgrp;
399 		int     oisoutatty, oisdiagatty;
400 
401 # ifndef CLOSE_ON_EXEC
402 		int     odidcch;
403 # endif  /* !CLOSE_ON_EXEC */
404 # ifdef BSDSIGS
405 		sigmask_t omask, ocsigmask;
406 # endif /* BSDSIGS */
407 
408 		/*
409 		 * Prepare for the vfork by saving everything that the child
410 		 * corrupts before it exec's. Note that in some signal
411 		 * implementations which keep the signal info in user space
412 		 * (e.g. Sun's) it will also be necessary to save and restore
413 		 * the current sigvec's for the signals the child touches
414 		 * before it exec's.
415 		 */
416 
417 		/*
418 		 * Sooooo true... If this is a Sun, save the sigvec's. (Skip
419 		 * Gilbrech - 11/22/87)
420 		 */
421 # ifdef SAVESIGVEC
422 		sigvec_t savesv[NSIGSAVED];
423 		sigmask_t savesm;
424 
425 # endif /* SAVESIGVEC */
426 		if (wanttty >= 0 && !nosigchld && !noexec) {
427 # ifdef BSDSIGS
428 		    csigmask = sigblock(sigmask(SIGCHLD));
429 # else /* !BSDSIGS */
430 		    (void) sighold(SIGCHLD);
431 # endif  /* BSDSIGS */
432 		    nosigchld = 1;
433 		}
434 # ifdef BSDSIGS
435 		omask = sigblock(sigmask(SIGCHLD)|sigmask(SIGINT));
436 # else /* !BSDSIGS */
437 		(void) sighold(SIGCHLD);
438 		(void) sighold(SIGINT);
439 # endif  /* BSDSIGS */
440 		ochild = child;
441 		osetintr = setintr;
442 		ohaderr = haderr;
443 		odidfds = didfds;
444 # ifndef CLOSE_ON_EXEC
445 		odidcch = didcch;
446 # endif /* !CLOSE_ON_EXEC */
447 		oSHIN = SHIN;
448 		oSHOUT = SHOUT;
449 		oSHDIAG = SHDIAG;
450 		oOLDSTD = OLDSTD;
451 		otpgrp = tpgrp;
452 		oisoutatty = isoutatty;
453 		oisdiagatty = isdiagatty;
454 # ifdef BSDSIGS
455 		ocsigmask = csigmask;
456 # endif /* BSDSIGS */
457 		onosigchld = nosigchld;
458 		Vsav = Vdp = 0;
459 		Vexpath = 0;
460 		Vt = 0;
461 # ifdef SAVESIGVEC
462 		savesm = savesigvec(savesv);
463 # endif /* SAVESIGVEC */
464 		if (use_fork)
465 		    pid = fork();
466 		else
467 		    pid = vfork();
468 
469 		if (pid < 0) {
470 # ifdef BSDSIGS
471 #  ifdef SAVESIGVEC
472 		    restoresigvec(savesv, savesm);
473 #  endif /* SAVESIGVEC */
474 		    (void) sigsetmask(omask);
475 # else /* !BSDSIGS */
476 		    (void) sigrelse(SIGCHLD);
477 		    (void) sigrelse(SIGINT);
478 # endif  /* BSDSIGS */
479 		    stderror(ERR_NOPROC);
480 		}
481 		forked++;
482 		if (pid) {	/* parent */
483 # ifdef SAVESIGVEC
484 		    restoresigvec(savesv, savesm);
485 # endif /* SAVESIGVEC */
486 		    child = ochild;
487 		    setintr = osetintr;
488 		    haderr = ohaderr;
489 		    didfds = odidfds;
490 		    SHIN = oSHIN;
491 # ifndef CLOSE_ON_EXEC
492 		    didcch = odidcch;
493 # endif /* !CLOSE_ON_EXEC */
494 		    SHOUT = oSHOUT;
495 		    SHDIAG = oSHDIAG;
496 		    OLDSTD = oOLDSTD;
497 		    tpgrp = otpgrp;
498 		    isoutatty = oisoutatty;
499 		    isdiagatty = oisdiagatty;
500 # ifdef BSDSIGS
501 		    csigmask = ocsigmask;
502 # endif /* BSDSIGS */
503 		    nosigchld = onosigchld;
504 
505 		    xfree((ptr_t) Vsav);
506 		    Vsav = 0;
507 		    xfree((ptr_t) Vdp);
508 		    Vdp = 0;
509 		    xfree((ptr_t) Vexpath);
510 		    Vexpath = 0;
511 		    blkfree((Char **) Vt);
512 		    Vt = 0;
513 		    /* this is from pfork() */
514 		    palloc(pid, t);
515 # ifdef BSDSIGS
516 		    (void) sigsetmask(omask);
517 # else /* !BSDSIGS */
518 		    (void) sigrelse(SIGCHLD);
519 		    (void) sigrelse(SIGINT);
520 # endif  /* BSDSIGS */
521 		}
522 		else {		/* child */
523 		    /* this is from pfork() */
524 		    int     pgrp;
525 		    bool    ignint = 0;
526 		    if (nosigchld) {
527 # ifdef BSDSIGS
528 			(void) sigsetmask(csigmask);
529 # else /* !BSDSIGS */
530 			(void) sigrelse(SIGCHLD);
531 # endif /* BSDSIGS */
532 			nosigchld = 0;
533 		    }
534 
535 		    if (setintr)
536 			ignint = (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT))
537 				|| (gointr && eq(gointr, STRminus));
538 		    pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
539 		    child++;
540 		    if (setintr) {
541 			setintr = 0;
542 /*
543  * casts made right for SunOS 4.0 by Douglas C. Schmidt
544  * <schmidt%sunshine.ics.uci.edu@ROME.ICS.UCI.EDU>
545  * (thanks! -- PWP)
546  *
547  * ignint ifs cleaned by Johan Widen <mcvax!osiris.sics.se!jw@uunet.UU.NET>
548  * (thanks again)
549  */
550 			if (ignint) {
551 			    (void) signal(SIGINT, SIG_IGN);
552 			    (void) signal(SIGQUIT, SIG_IGN);
553 			}
554 			else {
555 			    (void) signal(SIGINT,  vffree);
556 			    (void) signal(SIGQUIT, SIG_DFL);
557 			}
558 # ifdef BSDJOBS
559 			if (wanttty >= 0) {
560 			    (void) signal(SIGTSTP, SIG_DFL);
561 			    (void) signal(SIGTTIN, SIG_DFL);
562 			    (void) signal(SIGTTOU, SIG_DFL);
563 			}
564 # endif /* BSDJOBS */
565 
566 			(void) signal(SIGTERM, parterm);
567 		    }
568 		    else if (tpgrp == -1 &&
569 			     (t->t_dflg & F_NOINTERRUPT)) {
570 			(void) signal(SIGINT, SIG_IGN);
571 			(void) signal(SIGQUIT, SIG_IGN);
572 		    }
573 
574 		    pgetty(wanttty, pgrp);
575 
576 		    if (t->t_dflg & F_NOHUP)
577 			(void) signal(SIGHUP, SIG_IGN);
578 		    if (t->t_dflg & F_HUP)
579 			(void) signal(SIGHUP, SIG_DFL);
580 		    if (t->t_dflg & F_NICE) {
581 			int nval = SIGN_EXTEND_CHAR(t->t_nice);
582 # ifdef BSDNICE
583 			if (setpriority(PRIO_PROCESS, 0, nval) == -1 && errno)
584 				stderror(ERR_SYSTEM, "setpriority",
585 				    strerror(errno));
586 # else /* !BSDNICE */
587 			(void) nice(nval);
588 # endif /* BSDNICE */
589 		    }
590 # ifdef F_VER
591 		    if (t->t_dflg & F_VER) {
592 			tsetenv(STRSYSTYPE, t->t_systype ? STRbsd43 : STRsys53);
593 			dohash(NULL, NULL);
594 		    }
595 # endif /* F_VER */
596 		}
597 
598 	    }
599 #endif /* VFORK */
600 	}
601 	if (pid != 0) {
602 	    /*
603 	     * It would be better if we could wait for the whole job when we
604 	     * knew the last process had been started.  Pwait, in fact, does
605 	     * wait for the whole job anyway, but this test doesn't really
606 	     * express our intentions.
607 	     */
608 #ifdef BACKPIPE
609 	    if (didfds == 0 && t->t_dflg & F_PIPEOUT) {
610 		(void) close(pipeout[0]);
611 		(void) close(pipeout[1]);
612 	    }
613 	    if ((t->t_dflg & F_PIPEIN) != 0)
614 		break;
615 #else /* !BACKPIPE */
616 	    if (didfds == 0 && t->t_dflg & F_PIPEIN) {
617 		(void) close(pipein[0]);
618 		(void) close(pipein[1]);
619 	    }
620 	    if ((t->t_dflg & F_PIPEOUT) != 0)
621 		break;
622 #endif /* BACKPIPE */
623 
624 	    if (nosigchld) {
625 #ifdef BSDSIGS
626 		(void) sigsetmask(csigmask);
627 #else /* !BSDSIGS */
628 		(void) sigrelse(SIGCHLD);
629 #endif /* BSDSIGS */
630 		nosigchld = 0;
631 	    }
632 	    if ((t->t_dflg & F_AMPERSAND) == 0)
633 		pwait();
634 	    break;
635 	}
636 
637 	doio(t, pipein, pipeout);
638 #ifdef BACKPIPE
639 	if (t->t_dflg & F_PIPEIN) {
640 	    (void) close(pipein[0]);
641 	    (void) close(pipein[1]);
642 	}
643 #else /* !BACKPIPE */
644 	if (t->t_dflg & F_PIPEOUT) {
645 	    (void) close(pipeout[0]);
646 	    (void) close(pipeout[1]);
647 	}
648 #endif /* BACKPIPE */
649 	/*
650 	 * Perform a builtin function. If we are not forked, arrange for
651 	 * possible stopping
652 	 */
653 	if (bifunc) {
654 	    func(t, bifunc);
655 	    if (forked)
656 		exitstat();
657 	    break;
658 	}
659 	if (t->t_dtyp != NODE_PAREN) {
660 	    doexec(t, do_glob);
661 	    /* NOTREACHED */
662 	}
663 	/*
664 	 * For () commands must put new 0,1,2 in FSH* and recurse
665 	 */
666 	OLDSTD = dcopy(0, FOLDSTD);
667 	SHOUT = dcopy(1, FSHOUT);
668 	isoutatty = isatty(SHOUT);
669 	SHDIAG = dcopy(2, FSHDIAG);
670 	isdiagatty = isatty(SHDIAG);
671 	(void) close(SHIN);
672 	SHIN = -1;
673 #ifndef CLOSE_ON_EXEC
674 	didcch = 0;
675 #endif /* !CLOSE_ON_EXEC */
676 	didfds = 0;
677 	wanttty = -1;
678 	t->t_dspr->t_dflg |= t->t_dflg & F_NOINTERRUPT;
679 	execute(t->t_dspr, wanttty, NULL, NULL, do_glob);
680 	exitstat();
681 
682     case NODE_PIPE:
683 #ifdef BACKPIPE
684 	t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg &
685 			(F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT));
686 	execute(t->t_dcdr, wanttty, pv, pipeout, do_glob);
687 	t->t_dcar->t_dflg |= F_PIPEOUT |
688 	    (t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT));
689 	execute(t->t_dcar, wanttty, pipein, pv, do_glob);
690 #else /* !BACKPIPE */
691 	t->t_dcar->t_dflg |= F_PIPEOUT |
692 	    (t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT));
693 	execute(t->t_dcar, wanttty, pipein, pv, do_glob);
694 	t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg &
695 			(F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT));
696 	execute(t->t_dcdr, wanttty, pv, pipeout, do_glob);
697 #endif /* BACKPIPE */
698 	break;
699 
700     case NODE_LIST:
701 	if (t->t_dcar) {
702 	    t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT;
703 	    execute(t->t_dcar, wanttty, NULL, NULL, do_glob);
704 	    /*
705 	     * In strange case of A&B make a new job after A
706 	     */
707 	    if (t->t_dcar->t_dflg & F_AMPERSAND && t->t_dcdr &&
708 		(t->t_dcdr->t_dflg & F_AMPERSAND) == 0)
709 		pendjob();
710 	}
711 	if (t->t_dcdr) {
712 	    t->t_dcdr->t_dflg |= t->t_dflg &
713 		(F_NOFORK | F_NOINTERRUPT);
714 	    execute(t->t_dcdr, wanttty, NULL, NULL, do_glob);
715 	}
716 	break;
717 
718     case NODE_OR:
719     case NODE_AND:
720 	if (t->t_dcar) {
721 	    t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT;
722 	    execute(t->t_dcar, wanttty, NULL, NULL, do_glob);
723 	    if ((getn(varval(STRstatus)) == 0) !=
724 		(t->t_dtyp == NODE_AND)) {
725 		return;
726 	    }
727 	}
728 	if (t->t_dcdr) {
729 	    t->t_dcdr->t_dflg |= t->t_dflg &
730 		(F_NOFORK | F_NOINTERRUPT);
731 	    execute(t->t_dcdr, wanttty, NULL, NULL, do_glob);
732 	}
733 	break;
734 
735     default:
736 	break;
737     }
738     /*
739      * Fall through for all breaks from switch
740      *
741      * If there will be no more executions of this command, flush all file
742      * descriptors. Places that turn on the F_REPEAT bit are responsible for
743      * doing donefds after the last re-execution
744      */
745     if (didfds && !(t->t_dflg & F_REPEAT))
746 	donefds();
747 }
748 
749 #ifdef VFORK
750 static sigret_t
751 /*ARGSUSED*/
752 vffree(snum)
753 int snum;
754 {
755     register Char **v;
756 
757     USE(snum);
758     if ((v = gargv) != 0) {
759 	gargv = 0;
760 	xfree((ptr_t) v);
761     }
762 
763     if ((v = pargv) != 0) {
764 	pargv = 0;
765 	xfree((ptr_t) v);
766     }
767 
768     _exit(1);
769 #ifndef SIGVOID
770     /*NOTREACHED*/
771     return(0);
772 #endif /* SIGVOID */
773 }
774 #endif /* VFORK */
775 
776 /*
777  * Expand and glob the words after an i/o redirection.
778  * If more than one word is generated, then update the command vector.
779  *
780  * This is done differently in all the shells:
781  * 1. in the bourne shell and ksh globbing is not performed
782  * 2. Bash/csh say ambiguous
783  * 3. zsh does i/o to/from all the files
784  * 4. itcsh concatenates the words.
785  *
786  * I don't know what is best to do. I think that Ambiguous is better
787  * than restructuring the command vector, because the user can get
788  * unexpected results. In any case, the command vector restructuring
789  * code is present and the user can choose it by setting noambiguous
790  */
791 static Char *
792 splicepipe(t, cp)
793     register struct command *t;
794     Char *cp;	/* word after < or > */
795 {
796     Char *blk[2];
797 
798     if (adrof(STRnoambiguous)) {
799 	Char **pv;
800 
801 	blk[0] = Dfix1(cp); /* expand $ */
802 	blk[1] = NULL;
803 
804 	gflag = 0, tglob(blk);
805 	if (gflag) {
806 	    pv = globall(blk);
807 	    if (pv == NULL) {
808 		setname(short2str(blk[0]));
809 		xfree((ptr_t) blk[0]);
810 		stderror(ERR_NAME | ERR_NOMATCH);
811 	    }
812 	    gargv = NULL;
813 	    if (pv[1] != NULL) { /* we need to fix the command vector */
814 		Char **av = blkspl(t->t_dcom, &pv[1]);
815 		xfree((ptr_t) t->t_dcom);
816 		t->t_dcom = av;
817 	    }
818 	    xfree((ptr_t) blk[0]);
819 	    blk[0] = pv[0];
820 	    xfree((ptr_t) pv);
821 	}
822     }
823     else {
824 	Char buf[BUFSIZE];
825 
826 	(void) Strcpy(buf, blk[1] = Dfix1(cp));
827 	xfree((ptr_t) blk[1]);
828 	blk[0] = globone(buf, G_ERROR);
829     }
830     return(blk[0]);
831 }
832 
833 /*
834  * Perform io redirection.
835  * We may or maynot be forked here.
836  */
837 static void
838 doio(t, pipein, pipeout)
839     register struct command *t;
840     int    *pipein, *pipeout;
841 {
842     register int fd;
843     register Char *cp;
844     register unsigned long flags = t->t_dflg;
845 
846     if (didfds || (flags & F_REPEAT))
847 	return;
848     if ((flags & F_READ) == 0) {/* F_READ already done */
849 	if (t->t_dlef) {
850 	    char    tmp[MAXPATHLEN+1];
851 
852 	    /*
853 	     * so < /dev/std{in,out,err} work
854 	     */
855 	    (void) dcopy(SHIN, 0);
856 	    (void) dcopy(SHOUT, 1);
857 	    (void) dcopy(SHDIAG, 2);
858 	    cp = splicepipe(t, t->t_dlef);
859 	    (void) strncpy(tmp, short2str(cp), MAXPATHLEN);
860 	    tmp[MAXPATHLEN] = '\0';
861 	    xfree((ptr_t) cp);
862 	    if ((fd = open(tmp, O_RDONLY|O_LARGEFILE)) < 0)
863 		stderror(ERR_SYSTEM, tmp, strerror(errno));
864 	    /* allow input files larger than 2Gb  */
865 #ifndef WINNT_NATIVE
866 	    (void) fcntl(fd, O_LARGEFILE, 0);
867 #endif /*!WINNT_NATIVE*/
868 	    (void) dmove(fd, 0);
869 	}
870 	else if (flags & F_PIPEIN) {
871 	    (void) close(0);
872 	    (void) dup(pipein[0]);
873 	    (void) close(pipein[0]);
874 	    (void) close(pipein[1]);
875 	}
876 	else if ((flags & F_NOINTERRUPT) && tpgrp == -1) {
877 	    (void) close(0);
878 	    (void) open(_PATH_DEVNULL, O_RDONLY|O_LARGEFILE);
879 	}
880 	else {
881 	    (void) close(0);
882 	    (void) dup(OLDSTD);
883 #if defined(CLOSE_ON_EXEC) && defined(CLEX_DUPS)
884 	    /*
885 	     * PWP: Unlike Bezerkeley 4.3, FIONCLEX for Pyramid is preserved
886 	     * across dup()s, so we have to UNSET it here or else we get a
887 	     * command with NO stdin, stdout, or stderr at all (a bad thing
888 	     * indeed)
889 	     */
890 	    (void) close_on_exec(0, 0);
891 #endif /* CLOSE_ON_EXEC && CLEX_DUPS */
892 	}
893     }
894     if (t->t_drit) {
895 	char    tmp[MAXPATHLEN+1];
896 
897 	cp = splicepipe(t, t->t_drit);
898 	(void) strncpy(tmp, short2str(cp), MAXPATHLEN);
899 	tmp[MAXPATHLEN] = '\0';
900 	xfree((ptr_t) cp);
901 	/*
902 	 * so > /dev/std{out,err} work
903 	 */
904 	(void) dcopy(SHOUT, 1);
905 	(void) dcopy(SHDIAG, 2);
906 	if ((flags & F_APPEND) != 0) {
907 #ifdef O_APPEND
908 	    fd = open(tmp, O_WRONLY|O_APPEND|O_LARGEFILE);
909 #else /* !O_APPEND */
910 	    fd = open(tmp, O_WRONLY|O_LARGEFILE);
911 	    (void) lseek(fd, (off_t) 0, L_XTND);
912 #endif /* O_APPEND */
913 	}
914 	else
915 	    fd = 0;
916 	if ((flags & F_APPEND) == 0 || fd == -1) {
917 	    if (!(flags & F_OVERWRITE) && adrof(STRnoclobber)) {
918 		if (flags & F_APPEND)
919 		    stderror(ERR_SYSTEM, tmp, strerror(errno));
920 		chkclob(tmp);
921 	    }
922 	    if ((fd = creat(tmp, 0666)) < 0)
923 		stderror(ERR_SYSTEM, tmp, strerror(errno));
924 	    /* allow input files larger than 2Gb  */
925 #ifndef WINNT_NATIVE
926 	    (void) fcntl(fd, O_LARGEFILE, 0);
927 #endif /*!WINNT_NATIVE*/
928 	}
929 	(void) dmove(fd, 1);
930 	is1atty = isatty(1);
931     }
932     else if (flags & F_PIPEOUT) {
933 	(void) close(1);
934 	(void) dup(pipeout[1]);
935 	is1atty = 0;
936     }
937     else {
938 	(void) close(1);
939 	(void) dup(SHOUT);
940 	is1atty = isoutatty;
941 # if defined(CLOSE_ON_EXEC) && defined(CLEX_DUPS)
942 	(void) close_on_exec(1, 0);
943 # endif /* CLOSE_ON_EXEC && CLEX_DUPS */
944     }
945 
946     (void) close(2);
947     if (flags & F_STDERR) {
948 	(void) dup(1);
949 	is2atty = is1atty;
950     }
951     else {
952 	(void) dup(SHDIAG);
953 	is2atty = isdiagatty;
954 # if defined(CLOSE_ON_EXEC) && defined(CLEX_DUPS)
955 	(void) close_on_exec(2, 0);
956 # endif /* CLOSE_ON_EXEC && CLEX_DUPS */
957     }
958     didfds = 1;
959 }
960 
961 void
962 mypipe(pv)
963     register int *pv;
964 {
965 
966     if (pipe(pv) < 0)
967 	goto oops;
968     pv[0] = dmove(pv[0], -1);
969     pv[1] = dmove(pv[1], -1);
970     if (pv[0] >= 0 && pv[1] >= 0)
971 	return;
972 oops:
973     stderror(ERR_PIPE);
974 }
975 
976 static void
977 chkclob(cp)
978     register char *cp;
979 {
980     struct stat stb;
981 
982     if (stat(cp, &stb) < 0)
983 	return;
984     if (S_ISCHR(stb.st_mode))
985 	return;
986     stderror(ERR_EXISTS, cp);
987 }
988