xref: /dragonfly/contrib/tcsh-6/sh.sem.c (revision 25a2db75)
1 /* $Header: /p/tcsh/cvsroot/tcsh/sh.sem.c,v 3.80 2009/06/25 21:27:38 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("$tcsh: sh.sem.c,v 3.80 2009/06/25 21:27:38 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) && !defined(__GNU__) && !defined(__GLIBC__)
54 #  include <vfork.h>
55 # endif /* !MACH && SYSVREL == 0 && !Lynx && !BSD4_4 && !glibc */
56 #endif /* __sparc__ || sparc */
57 
58 #ifdef VFORK
59 static	void		vffree		(int);
60 #endif
61 static	Char		*splicepipe	(struct command *, Char *);
62 static	void		 doio		(struct command *, int *, int *);
63 static	void		 chkclob	(const 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(struct command *t, volatile int wanttty, int *pipein, int *pipeout,
88     int do_glob)
89 {
90     int    forked = 0;
91     const struct biltins * volatile bifunc;
92     pid_t pid = 0;
93     int     pv[2];
94     sigset_t set;
95     static sigset_t csigset;
96 #ifdef VFORK
97     static int onosigchld = 0;
98 #endif /* VFORK */
99     static int nosigchld = 0;
100 
101     (void) &wanttty;
102     (void) &forked;
103     (void) &bifunc;
104 
105     if (t == 0)
106 	return;
107 
108 #ifdef WINNT_NATIVE
109     {
110         if ((varval(STRNTslowexec) == STRNULL) &&
111             !t->t_dcdr && !t->t_dcar && !t->t_dflg && !didfds &&
112             (intty || intact) && (t->t_dtyp == NODE_COMMAND) &&
113 	    !isbfunc(t)) {
114 	    if ((t->t_dcom[0][0] & (QUOTE | TRIM)) == QUOTE)
115 		(void) Strcpy(t->t_dcom[0], t->t_dcom[0] + 1);
116 	    Dfix(t);
117             if (nt_try_fast_exec(t) == 0)
118                 return;
119         }
120     }
121 #endif /* WINNT_NATIVE */
122 
123     /*
124      * Ed hutchins@sgi.com & Dominic dbg@sgi.com
125      * Sat Feb 25 03:13:11 PST 1995
126      * try implicit cd if we have a 1 word command
127      */
128     if (implicit_cd && (intty || intact) && t->t_dcom && t->t_dcom[0] &&
129 	 t->t_dcom[0][0] && (blklen(t->t_dcom) == 1) && !noexec) {
130 	Char *sCName;
131 	struct stat stbuf;
132 	char *pathname;
133 
134 	sCName = dollar(t->t_dcom[0]);
135 	if (sCName != NULL && sCName[0] == '~') {
136 	    struct Strbuf buf = Strbuf_INIT;
137 	    const Char *name_end;
138 
139 	    for (name_end = sCName + 1; *name_end != '\0' && *name_end != '/';
140 		 name_end++)
141 		continue;
142 	    if (name_end != sCName + 1) {
143 		Char *name, *home;
144 
145 		name = Strnsave(sCName + 1, name_end - (sCName + 1));
146 		home = gethdir(name);
147 		if (home != NULL) {
148 		    Strbuf_append(&buf, home);
149 		    xfree(home);
150 		} else
151 		    Strbuf_append(&buf, name);
152 		xfree(name);
153 	    } else
154 		Strbuf_append(&buf, varval(STRhome));
155 	    Strbuf_append(&buf, name_end);
156 	    xfree(sCName);
157 	    sCName = Strbuf_finish(&buf);
158 	}
159 
160 	pathname = short2str(sCName);
161 	xfree(sCName);
162 	/* if this is a dir, tack a "cd" on as the first arg */
163 	if (pathname != NULL &&
164 	    ((stat(pathname, &stbuf) != -1 && S_ISDIR(stbuf.st_mode))
165 #ifdef WINNT_NATIVE
166 	     || (pathname[0] && pathname[1] == ':' && pathname[2] == '\0')
167 #endif /* WINNT_NATIVE */
168 	     )) {
169 	    Char *vCD[2];
170 	    Char **ot_dcom = t->t_dcom;
171 
172 	    vCD[0] = Strsave(STRcd);
173 	    vCD[1] = NULL;
174 	    t->t_dcom = blkspl(vCD, ot_dcom);
175 	    xfree(ot_dcom);
176 	    if (implicit_cd > 1) {
177 		blkpr(t->t_dcom);
178 		xputchar( '\n' );
179 	    }
180 	}
181     }
182 
183     /*
184      * From: Michael Schroeder <mlschroe@immd4.informatik.uni-erlangen.de>
185      * Don't check for wantty > 0...
186      */
187     if (t->t_dflg & F_AMPERSAND)
188 	wanttty = 0;
189     switch (t->t_dtyp) {
190 
191     case NODE_COMMAND:
192 	if ((t->t_dcom[0][0] & (QUOTE | TRIM)) == QUOTE)
193 	    memmove(t->t_dcom[0], t->t_dcom[0] + 1,
194 		    (Strlen(t->t_dcom[0] + 1) + 1) * sizeof (*t->t_dcom[0]));
195 	if ((t->t_dflg & F_REPEAT) == 0)
196 	    Dfix(t);		/* $ " ' \ */
197 	if (t->t_dcom[0] == 0) {
198 	    return;
199 	}
200 	/*FALLTHROUGH*/
201 
202     case NODE_PAREN:
203 #ifdef BACKPIPE
204 	if (t->t_dflg & F_PIPEIN)
205 	    mypipe(pipein);
206 #else /* !BACKPIPE */
207 	if (t->t_dflg & F_PIPEOUT)
208 	    mypipe(pipeout);
209 #endif /* BACKPIPE */
210 	/*
211 	 * Must do << early so parent will know where input pointer should be.
212 	 * If noexec then this is all we do.
213 	 */
214 	if (t->t_dflg & F_READ) {
215 	    xclose(0);
216 	    heredoc(t->t_dlef);
217 	    if (noexec)
218 		xclose(0);
219 	}
220 
221 	setcopy(STRstatus, STR0, VAR_READWRITE);
222 
223 	/*
224 	 * This mess is the necessary kludge to handle the prefix builtins:
225 	 * nice, nohup, time.  These commands can also be used by themselves,
226 	 * and this is not handled here. This will also work when loops are
227 	 * parsed.
228 	 */
229 	while (t->t_dtyp == NODE_COMMAND)
230 	    if (eq(t->t_dcom[0], STRnice)) {
231 		if (t->t_dcom[1]) {
232 		    if (strchr("+-", t->t_dcom[1][0])) {
233 			if (t->t_dcom[2]) {
234 			    setname("nice");
235 			    t->t_nice =
236 				getn(t->t_dcom[1]);
237 			    lshift(t->t_dcom, 2);
238 			    t->t_dflg |= F_NICE;
239 			}
240 			else
241 			    break;
242 		    }
243 		    else {
244 			t->t_nice = 4;
245 			lshift(t->t_dcom, 1);
246 			t->t_dflg |= F_NICE;
247 		    }
248 		}
249 		else
250 		    break;
251 	    }
252 	    else if (eq(t->t_dcom[0], STRnohup)) {
253 		if (t->t_dcom[1]) {
254 		    t->t_dflg |= F_NOHUP;
255 		    lshift(t->t_dcom, 1);
256 		}
257 		else
258 		    break;
259 	    }
260 	    else if (eq(t->t_dcom[0], STRhup)) {
261 		if (t->t_dcom[1]) {
262 		    t->t_dflg |= F_HUP;
263 		    lshift(t->t_dcom, 1);
264 		}
265 		else
266 		    break;
267 	    }
268 	    else if (eq(t->t_dcom[0], STRtime)) {
269 		if (t->t_dcom[1]) {
270 		    t->t_dflg |= F_TIME;
271 		    lshift(t->t_dcom, 1);
272 		}
273 		else
274 		    break;
275 	    }
276 #ifdef F_VER
277 	    else if (eq(t->t_dcom[0], STRver))
278 		if (t->t_dcom[1] && t->t_dcom[2]) {
279 		    setname("ver");
280 		    t->t_systype = getv(t->t_dcom[1]);
281 		    lshift(t->t_dcom, 2);
282 		    t->t_dflg |= F_VER;
283 		}
284 		else
285 		    break;
286 #endif  /* F_VER */
287 	    else
288 		break;
289 
290 	/* is it a command */
291 	if (t->t_dtyp == NODE_COMMAND) {
292 	    /*
293 	     * Check if we have a builtin function and remember which one.
294 	     */
295 	    bifunc = isbfunc(t);
296  	    if (noexec) {
297 		/*
298 		 * Continue for builtins that are part of the scripting language
299 		 */
300 		if (bifunc == NULL)
301 		    break;
302 		if (bifunc->bfunct != (bfunc_t)dobreak	&&
303 		    bifunc->bfunct != (bfunc_t)docontin	&&
304 		    bifunc->bfunct != (bfunc_t)doelse	&&
305 		    bifunc->bfunct != (bfunc_t)doend	&&
306 		    bifunc->bfunct != (bfunc_t)doforeach&&
307 		    bifunc->bfunct != (bfunc_t)dogoto	&&
308 		    bifunc->bfunct != (bfunc_t)doif	&&
309 		    bifunc->bfunct != (bfunc_t)dorepeat	&&
310 		    bifunc->bfunct != (bfunc_t)doswbrk	&&
311 		    bifunc->bfunct != (bfunc_t)doswitch	&&
312 		    bifunc->bfunct != (bfunc_t)dowhile	&&
313 		    bifunc->bfunct != (bfunc_t)dozip)
314 		    break;
315 	    }
316 	}
317 	else {			/* not a command */
318 	    bifunc = NULL;
319 	    if (noexec)
320 		break;
321 	}
322 
323 	/*
324 	 * GrP Executing a command - run jobcmd hook
325 	 * Don't run for builtins
326 	 * Don't run if we're not in a tty
327 	 * Don't run if we're not really executing
328 	 */
329 	/*
330 	 * CR  -  Charles Ross Aug 2005
331 	 * added "isoutatty".
332 	 * The new behavior is that the jobcmd won't be executed
333 	 * if stdout (SHOUT) isnt attached to a tty.. IE when
334 	 * redirecting, or using backquotes etc..
335 	 */
336 	if (t->t_dtyp == NODE_COMMAND && !bifunc && !noexec && intty && isoutatty) {
337 	    Char *cmd = unparse(t);
338 
339 	    cleanup_push(cmd, xfree);
340 	    job_cmd(cmd);
341 	    cleanup_until(cmd);
342 	}
343 
344 	/*
345 	 * We fork only if we are timed, or are not the end of a parenthesized
346 	 * list and not a simple builtin function. Simple meaning one that is
347 	 * not pipedout, niced, nohupped, or &'d. It would be nice(?) to not
348 	 * fork in some of these cases.
349 	 */
350 	/*
351 	 * Prevent forking cd, pushd, popd, chdir cause this will cause the
352 	 * shell not to change dir!
353 	 */
354 #ifdef BACKPIPE
355 	/*
356 	 * Can't have NOFORK for the tail of a pipe - because it is not the
357 	 * last command spawned (even if it is at the end of a parenthesised
358 	 * list).
359 	 */
360 	if (t->t_dflg & F_PIPEIN)
361 	    t->t_dflg &= ~(F_NOFORK);
362 #endif /* BACKPIPE */
363 	if (bifunc && (bifunc->bfunct == (bfunc_t)dochngd ||
364 		       bifunc->bfunct == (bfunc_t)dopushd ||
365 		       bifunc->bfunct == (bfunc_t)dopopd))
366 	    t->t_dflg &= ~(F_NICE);
367 	if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 &&
368 	     (!bifunc || t->t_dflg &
369 	      (F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP | F_HUP)))) ||
370 	/*
371 	 * We have to fork for eval too.
372 	 */
373 	    (bifunc && (t->t_dflg & F_PIPEIN) != 0 &&
374 	     bifunc->bfunct == (bfunc_t)doeval)) {
375 #ifdef VFORK
376 	    if (t->t_dtyp == NODE_PAREN ||
377 		t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc)
378 #endif /* VFORK */
379 	    {
380 		forked++;
381 		/*
382 		 * We need to block SIGCHLD here, so that if the process does
383 		 * not die before we can set the process group
384 		 */
385 		if (wanttty >= 0 && !nosigchld) {
386 		    sigemptyset(&set);
387 		    sigaddset(&set, SIGCHLD);
388 		    (void)sigprocmask(SIG_BLOCK, &set, &csigset);
389 
390 		    nosigchld = 1;
391 		}
392 
393 		pid = pfork(t, wanttty);
394 		if (pid == 0 && nosigchld) {
395 		    sigprocmask(SIG_SETMASK, &csigset, NULL);
396 		    nosigchld = 0;
397 		}
398 		else if (pid != 0 && (t->t_dflg & F_AMPERSAND))
399 		    backpid = pid;
400 	    }
401 
402 #ifdef VFORK
403 	    else {
404 		int     ochild, osetintr, ohaderr, odidfds;
405 		int     oSHIN, oSHOUT, oSHDIAG, oOLDSTD, otpgrp;
406 		int     oisoutatty, oisdiagatty;
407 		sigset_t oset, ocsigset;
408 # ifndef CLOSE_ON_EXEC
409 		int     odidcch;
410 # endif  /* !CLOSE_ON_EXEC */
411 
412 		/*
413 		 * Prepare for the vfork by saving everything that the child
414 		 * corrupts before it exec's. Note that in some signal
415 		 * implementations which keep the signal info in user space
416 		 * (e.g. Sun's) it will also be necessary to save and restore
417 		 * the current sigvec's for the signals the child touches
418 		 * before it exec's.
419 		 */
420 
421 		/*
422 		 * Sooooo true... If this is a Sun, save the sigvec's. (Skip
423 		 * Gilbrech - 11/22/87)
424 		 */
425 # ifdef SAVESIGVEC
426 		struct sigaction savesv[NSIGSAVED];
427 		sigset_t savesm;
428 
429 # endif /* SAVESIGVEC */
430 		if (wanttty >= 0 && !nosigchld && !noexec) {
431 		    sigemptyset(&set);
432 		    sigaddset(&set, SIGCHLD);
433 		    (void)sigprocmask(SIG_BLOCK, &set, &csigset);
434 		    nosigchld = 1;
435 		}
436 		sigemptyset(&set);
437 		sigaddset(&set, SIGCHLD);
438 		sigaddset(&set, SIGINT);
439 		(void)sigprocmask(SIG_BLOCK, &set, &oset);
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 		ocsigset = csigset;
455 		onosigchld = nosigchld;
456 		Vsav = Vdp = 0;
457 		Vexpath = 0;
458 		Vt = 0;
459 # ifdef SAVESIGVEC
460 		savesigvec(savesv, savesm);
461 # endif /* SAVESIGVEC */
462 		if (use_fork)
463 		    pid = fork();
464 		else
465 		    pid = vfork();
466 
467 		if (pid < 0) {
468 # ifdef SAVESIGVEC
469 		    restoresigvec(savesv, savesm);
470 # endif /* SAVESIGVEC */
471 		    sigprocmask(SIG_SETMASK, &oset, NULL);
472 		    stderror(ERR_NOPROC);
473 		}
474 		forked++;
475 		if (pid) {	/* parent */
476 # ifdef SAVESIGVEC
477 		    restoresigvec(savesv, savesm);
478 # endif /* SAVESIGVEC */
479 		    child = ochild;
480 		    setintr = osetintr;
481 		    haderr = ohaderr;
482 		    didfds = odidfds;
483 		    SHIN = oSHIN;
484 # ifndef CLOSE_ON_EXEC
485 		    didcch = odidcch;
486 # endif /* !CLOSE_ON_EXEC */
487 		    SHOUT = oSHOUT;
488 		    SHDIAG = oSHDIAG;
489 		    OLDSTD = oOLDSTD;
490 		    tpgrp = otpgrp;
491 		    isoutatty = oisoutatty;
492 		    isdiagatty = oisdiagatty;
493 		    csigset = ocsigset;
494 		    nosigchld = onosigchld;
495 
496 		    xfree(Vsav);
497 		    Vsav = 0;
498 		    xfree(Vdp);
499 		    Vdp = 0;
500 		    xfree(Vexpath);
501 		    Vexpath = 0;
502 		    blk_cleanup(Vt);
503 		    Vt = 0;
504 		    /* this is from pfork() */
505 		    palloc(pid, t);
506 		    sigprocmask(SIG_SETMASK, &oset, NULL);
507 		}
508 		else {		/* child */
509 		    /* this is from pfork() */
510 		    pid_t pgrp;
511 		    int    ignint = 0;
512 		    if (nosigchld) {
513 			sigprocmask(SIG_SETMASK, &csigset, NULL);
514 			nosigchld = 0;
515 		    }
516 
517 		    if (setintr)
518 			ignint = (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT))
519 				|| (gointr && eq(gointr, STRminus));
520 		    pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
521 		    child++;
522 		    if (setintr) {
523 			setintr = 0;
524 /*
525  * casts made right for SunOS 4.0 by Douglas C. Schmidt
526  * <schmidt%sunshine.ics.uci.edu@ROME.ICS.UCI.EDU>
527  * (thanks! -- PWP)
528  *
529  * ignint ifs cleaned by Johan Widen <mcvax!osiris.sics.se!jw@uunet.UU.NET>
530  * (thanks again)
531  */
532 			if (ignint) {
533 			    (void) signal(SIGINT, SIG_IGN);
534 			    (void) signal(SIGQUIT, SIG_IGN);
535 			}
536 			else {
537 			    (void) signal(SIGINT, vffree);
538 			    (void) signal(SIGQUIT, SIG_DFL);
539 			}
540 # ifdef BSDJOBS
541 			if (wanttty >= 0) {
542 			    (void) signal(SIGTSTP, SIG_DFL);
543 			    (void) signal(SIGTTIN, SIG_DFL);
544 			    (void) signal(SIGTTOU, SIG_DFL);
545 			}
546 # endif /* BSDJOBS */
547 
548 			sigaction(SIGTERM, &parterm, NULL);
549 		    }
550 		    else if (tpgrp == -1 &&
551 			     (t->t_dflg & F_NOINTERRUPT)) {
552 			(void) signal(SIGINT, SIG_IGN);
553 			(void) signal(SIGQUIT, SIG_IGN);
554 		    }
555 
556 		    pgetty(wanttty, pgrp);
557 
558 		    if (t->t_dflg & F_NOHUP)
559 			(void) signal(SIGHUP, SIG_IGN);
560 		    if (t->t_dflg & F_HUP)
561 			(void) signal(SIGHUP, SIG_DFL);
562 		    if (t->t_dflg & F_NICE) {
563 			int nval = SIGN_EXTEND_CHAR(t->t_nice);
564 # ifdef HAVE_SETPRIORITY
565 			if (setpriority(PRIO_PROCESS, 0, nval) == -1 && errno)
566 				stderror(ERR_SYSTEM, "setpriority",
567 				    strerror(errno));
568 # else /* !HAVE_SETPRIORITY */
569 			(void) nice(nval);
570 # endif /* HAVE_SETPRIORITY */
571 		    }
572 # ifdef F_VER
573 		    if (t->t_dflg & F_VER) {
574 			tsetenv(STRSYSTYPE, t->t_systype ? STRbsd43 : STRsys53);
575 			dohash(NULL, NULL);
576 		    }
577 # endif /* F_VER */
578 		}
579 
580 	    }
581 #endif /* VFORK */
582 	}
583 	if (pid != 0) {
584 	    /*
585 	     * It would be better if we could wait for the whole job when we
586 	     * knew the last process had been started.  Pwait, in fact, does
587 	     * wait for the whole job anyway, but this test doesn't really
588 	     * express our intentions.
589 	     */
590 #ifdef BACKPIPE
591 	    if (didfds == 0 && t->t_dflg & F_PIPEOUT) {
592 		xclose(pipeout[0]);
593 		xclose(pipeout[1]);
594 	    }
595 	    if ((t->t_dflg & F_PIPEIN) != 0)
596 		break;
597 #else /* !BACKPIPE */
598 	    if (didfds == 0 && t->t_dflg & F_PIPEIN) {
599 		xclose(pipein[0]);
600 		xclose(pipein[1]);
601 	    }
602 	    if ((t->t_dflg & F_PIPEOUT) != 0)
603 		break;
604 #endif /* BACKPIPE */
605 
606 	    if (nosigchld) {
607 		sigprocmask(SIG_SETMASK, &csigset, NULL);
608 		nosigchld = 0;
609 	    }
610 	    if ((t->t_dflg & F_AMPERSAND) == 0)
611 		pwait();
612 	    break;
613 	}
614 
615 	doio(t, pipein, pipeout);
616 #ifdef BACKPIPE
617 	if (t->t_dflg & F_PIPEIN) {
618 	    xclose(pipein[0]);
619 	    xclose(pipein[1]);
620 	}
621 #else /* !BACKPIPE */
622 	if (t->t_dflg & F_PIPEOUT) {
623 	    xclose(pipeout[0]);
624 	    xclose(pipeout[1]);
625 	}
626 #endif /* BACKPIPE */
627 	/*
628 	 * Perform a builtin function. If we are not forked, arrange for
629 	 * possible stopping
630 	 */
631 	if (bifunc) {
632 	    func(t, bifunc);
633 	    if (forked)
634 		exitstat();
635 	    else {
636 		if (adrof(STRprintexitvalue)) {
637 		    int rv = getn(varval(STRstatus));
638 		    if (rv != 0)
639 			xprintf(CGETS(17, 2, "Exit %d\n"), rv);
640 		}
641 	    }
642 	    break;
643 	}
644 	if (t->t_dtyp != NODE_PAREN) {
645 	    doexec(t, do_glob);
646 	    /* NOTREACHED */
647 	}
648 	/*
649 	 * For () commands must put new 0,1,2 in FSH* and recurse
650 	 */
651 	(void)close_on_exec(OLDSTD = dcopy(0, FOLDSTD), 1);
652 	(void)close_on_exec(SHOUT = dcopy(1, FSHOUT), 1);
653 	isoutatty = isatty(SHOUT);
654 	(void)close_on_exec(SHDIAG = dcopy(2, FSHDIAG), 1);
655 	isdiagatty = isatty(SHDIAG);
656 	xclose(SHIN);
657 	SHIN = -1;
658 #ifndef CLOSE_ON_EXEC
659 	didcch = 0;
660 #else
661 	(void) close_on_exec(FSHOUT, 1);
662 	(void) close_on_exec(FSHDIAG, 1);
663 	(void) close_on_exec(FOLDSTD, 1);
664 #endif /* !CLOSE_ON_EXEC */
665 	didfds = 0;
666 	wanttty = -1;
667 	t->t_dspr->t_dflg |= t->t_dflg & F_NOINTERRUPT;
668 	execute(t->t_dspr, wanttty, NULL, NULL, do_glob);
669 	exitstat();
670 
671     case NODE_PIPE:
672 #ifdef BACKPIPE
673 	t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg &
674 			(F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT));
675 	execute(t->t_dcdr, wanttty, pv, pipeout, do_glob);
676 	t->t_dcar->t_dflg |= F_PIPEOUT |
677 	    (t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT));
678 	execute(t->t_dcar, wanttty, pipein, pv, do_glob);
679 #else /* !BACKPIPE */
680 	t->t_dcar->t_dflg |= F_PIPEOUT |
681 	    (t->t_dflg & (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT));
682 	execute(t->t_dcar, wanttty, pipein, pv, do_glob);
683 	t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg &
684 			(F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT));
685 	execute(t->t_dcdr, wanttty, pv, pipeout, do_glob);
686 #endif /* BACKPIPE */
687 	break;
688 
689     case NODE_LIST:
690 	if (t->t_dcar) {
691 	    t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT;
692 	    execute(t->t_dcar, wanttty, NULL, NULL, do_glob);
693 	    /*
694 	     * In strange case of A&B make a new job after A
695 	     */
696 	    if (t->t_dcar->t_dflg & F_AMPERSAND && t->t_dcdr &&
697 		(t->t_dcdr->t_dflg & F_AMPERSAND) == 0)
698 		pendjob();
699 	}
700 	if (t->t_dcdr) {
701 	    t->t_dcdr->t_dflg |= t->t_dflg &
702 		(F_NOFORK | F_NOINTERRUPT);
703 	    execute(t->t_dcdr, wanttty, NULL, NULL, do_glob);
704 	}
705 	break;
706 
707     case NODE_OR:
708     case NODE_AND:
709 	if (t->t_dcar) {
710 	    t->t_dcar->t_dflg |= t->t_dflg & F_NOINTERRUPT;
711 	    execute(t->t_dcar, wanttty, NULL, NULL, do_glob);
712 	    if ((getn(varval(STRstatus)) == 0) !=
713 		(t->t_dtyp == NODE_AND)) {
714 		return;
715 	    }
716 	}
717 	if (t->t_dcdr) {
718 	    t->t_dcdr->t_dflg |= t->t_dflg &
719 		(F_NOFORK | F_NOINTERRUPT);
720 	    execute(t->t_dcdr, wanttty, NULL, NULL, do_glob);
721 	}
722 	break;
723 
724     default:
725 	break;
726     }
727     /*
728      * Fall through for all breaks from switch
729      *
730      * If there will be no more executions of this command, flush all file
731      * descriptors. Places that turn on the F_REPEAT bit are responsible for
732      * doing donefds after the last re-execution
733      */
734     if (didfds && !(t->t_dflg & F_REPEAT))
735 	donefds();
736 }
737 
738 #ifdef VFORK
739 static void
740 /*ARGSUSED*/
741 vffree(int snum)
742 {
743     USE(snum);
744 
745     _exit(1);
746 }
747 #endif /* VFORK */
748 
749 /*
750  * Expand and glob the words after an i/o redirection.
751  * If more than one word is generated, then update the command vector.
752  *
753  * This is done differently in all the shells:
754  * 1. in the bourne shell and ksh globbing is not performed
755  * 2. Bash/csh say ambiguous
756  * 3. zsh does i/o to/from all the files
757  * 4. itcsh concatenates the words.
758  *
759  * I don't know what is best to do. I think that Ambiguous is better
760  * than restructuring the command vector, because the user can get
761  * unexpected results. In any case, the command vector restructuring
762  * code is present and the user can choose it by setting noambiguous
763  */
764 static Char *
765 splicepipe(struct command *t, Char *cp)
766 {
767     Char *blk[2];
768 
769     if (adrof(STRnoambiguous)) {
770 	Char **pv;
771 	int gflag;
772 
773 	blk[0] = Dfix1(cp); /* expand $ */
774 	blk[1] = NULL;
775 
776 	gflag = tglob(blk);
777 	if (gflag) {
778 	    pv = globall(blk, gflag);
779 	    if (pv == NULL) {
780 		setname(short2str(blk[0]));
781 		xfree(blk[0]);
782 		stderror(ERR_NAME | ERR_NOMATCH);
783 	    }
784 	    if (pv[1] != NULL) { /* we need to fix the command vector */
785 		Char **av = blkspl(t->t_dcom, &pv[1]);
786 		xfree(t->t_dcom);
787 		t->t_dcom = av;
788 	    }
789 	    xfree(blk[0]);
790 	    blk[0] = pv[0];
791 	    xfree(pv);
792 	}
793     }
794     else {
795 	Char *buf;
796 
797 	buf = Dfix1(cp);
798 	cleanup_push(buf, xfree);
799 	blk[0] = globone(buf, G_ERROR);
800 	cleanup_until(buf);
801     }
802     return(blk[0]);
803 }
804 
805 /*
806  * Perform io redirection.
807  * We may or maynot be forked here.
808  */
809 static void
810 doio(struct command *t, int *pipein, int *pipeout)
811 {
812     int fd;
813     Char *cp;
814     unsigned long flags = t->t_dflg;
815 
816     if (didfds || (flags & F_REPEAT))
817 	return;
818     if ((flags & F_READ) == 0) {/* F_READ already done */
819 	if (t->t_dlef) {
820 	    char *tmp;
821 
822 	    /*
823 	     * so < /dev/std{in,out,err} work
824 	     */
825 	    (void) dcopy(SHIN, 0);
826 	    (void) dcopy(SHOUT, 1);
827 	    (void) dcopy(SHDIAG, 2);
828 	    cp = splicepipe(t, t->t_dlef);
829 	    tmp = strsave(short2str(cp));
830 	    xfree(cp);
831 	    cleanup_push(tmp, xfree);
832 	    if ((fd = xopen(tmp, O_RDONLY|O_LARGEFILE)) < 0)
833 		stderror(ERR_SYSTEM, tmp, strerror(errno));
834 	    cleanup_until(tmp);
835 	    /* allow input files larger than 2Gb  */
836 #ifndef WINNT_NATIVE
837 	    (void) fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_LARGEFILE);
838 #endif /*!WINNT_NATIVE*/
839 	    (void) dmove(fd, 0);
840 	}
841 	else if (flags & F_PIPEIN) {
842 	    xclose(0);
843 	    IGNORE(dup(pipein[0]));
844 	    xclose(pipein[0]);
845 	    xclose(pipein[1]);
846 	}
847 	else if ((flags & F_NOINTERRUPT) && tpgrp == -1) {
848 	    xclose(0);
849 	    (void) xopen(_PATH_DEVNULL, O_RDONLY|O_LARGEFILE);
850 	}
851 	else {
852 	    xclose(0);
853 	    IGNORE(dup(OLDSTD));
854 #if defined(CLOSE_ON_EXEC) && defined(CLEX_DUPS)
855 	    /*
856 	     * PWP: Unlike Bezerkeley 4.3, FIONCLEX for Pyramid is preserved
857 	     * across dup()s, so we have to UNSET it here or else we get a
858 	     * command with NO stdin, stdout, or stderr at all (a bad thing
859 	     * indeed)
860 	     */
861 	    (void) close_on_exec(0, 0);
862 #endif /* CLOSE_ON_EXEC && CLEX_DUPS */
863 	}
864     }
865     if (t->t_drit) {
866 	char *tmp;
867 
868 	cp = splicepipe(t, t->t_drit);
869 	tmp = strsave(short2str(cp));
870 	xfree(cp);
871 	cleanup_push(tmp, xfree);
872 	/*
873 	 * so > /dev/std{out,err} work
874 	 */
875 	(void) dcopy(SHOUT, 1);
876 	(void) dcopy(SHDIAG, 2);
877 	if ((flags & F_APPEND) != 0) {
878 #ifdef O_APPEND
879 	    fd = xopen(tmp, O_WRONLY|O_APPEND|O_LARGEFILE);
880 #else /* !O_APPEND */
881 	    fd = xopen(tmp, O_WRONLY|O_LARGEFILE);
882 	    (void) lseek(fd, (off_t) 0, L_XTND);
883 #endif /* O_APPEND */
884 	}
885 	else
886 	    fd = 0;
887 	if ((flags & F_APPEND) == 0 || fd == -1) {
888 	    if (!(flags & F_OVERWRITE) && adrof(STRnoclobber)) {
889 		if (flags & F_APPEND)
890 		    stderror(ERR_SYSTEM, tmp, strerror(errno));
891 		chkclob(tmp);
892 	    }
893 	    if ((fd = xcreat(tmp, 0666)) < 0)
894 		stderror(ERR_SYSTEM, tmp, strerror(errno));
895 	    /* allow input files larger than 2Gb  */
896 #ifndef WINNT_NATIVE
897 	    (void) fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_LARGEFILE);
898 #endif /*!WINNT_NATIVE*/
899 	}
900 	cleanup_until(tmp);
901 	(void) dmove(fd, 1);
902 	is1atty = isatty(1);
903     }
904     else if (flags & F_PIPEOUT) {
905 	xclose(1);
906 	IGNORE(dup(pipeout[1]));
907 	is1atty = 0;
908     }
909     else {
910 	xclose(1);
911 	IGNORE(dup(SHOUT));
912 	is1atty = isoutatty;
913 # if defined(CLOSE_ON_EXEC) && defined(CLEX_DUPS)
914 	(void) close_on_exec(1, 0);
915 # endif /* CLOSE_ON_EXEC && CLEX_DUPS */
916     }
917 
918     xclose(2);
919     if (flags & F_STDERR) {
920 	IGNORE(dup(1));
921 	is2atty = is1atty;
922     }
923     else {
924 	IGNORE(dup(SHDIAG));
925 	is2atty = isdiagatty;
926 # if defined(CLOSE_ON_EXEC) && defined(CLEX_DUPS)
927 	(void) close_on_exec(2, 0);
928 # endif /* CLOSE_ON_EXEC && CLEX_DUPS */
929     }
930     didfds = 1;
931 }
932 
933 void
934 mypipe(int *pv)
935 {
936 
937     if (pipe(pv) < 0)
938 	goto oops;
939     (void)close_on_exec(pv[0] = dmove(pv[0], -1), 1);
940     (void)close_on_exec(pv[1] = dmove(pv[1], -1), 1);
941     if (pv[0] >= 0 && pv[1] >= 0)
942 	return;
943     if (pv[0] >= 0)
944 	xclose(pv[0]);
945     if (pv[1] >= 0)
946 	xclose(pv[1]);
947 oops:
948     stderror(ERR_PIPE);
949 }
950 
951 static void
952 chkclob(const char *cp)
953 {
954     struct stat stb;
955 
956     if (stat(cp, &stb) < 0)
957 	return;
958     if (S_ISCHR(stb.st_mode))
959 	return;
960     stderror(ERR_EXISTS, cp);
961 }
962