xref: /freebsd/contrib/tcsh/sh.sem.c (revision 5bf5ca772c6de2d53344a78cf461447cc322ccea)
1 /* $Header: /p/tcsh/cvsroot/tcsh/sh.sem.c,v 3.90 2015/10/31 18:54:42 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 3.90 2015/10/31 18:54:42 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 	    int old_pintr_disabled;
216 
217 	    xclose(0);
218 	    if (setintr)
219 		pintr_push_enable(&old_pintr_disabled);
220 	    heredoc(t->t_dlef);
221 	    if (setintr)
222 		cleanup_until(&old_pintr_disabled);
223 	    if (noexec)
224 		xclose(0);
225 	}
226 
227 	setcopy(STRstatus, STR0, VAR_READWRITE);
228 
229 	/*
230 	 * This mess is the necessary kludge to handle the prefix builtins:
231 	 * nice, nohup, time.  These commands can also be used by themselves,
232 	 * and this is not handled here. This will also work when loops are
233 	 * parsed.
234 	 */
235 	while (t->t_dtyp == NODE_COMMAND)
236 	    if (eq(t->t_dcom[0], STRnice)) {
237 		if (t->t_dcom[1]) {
238 		    if (strchr("+-", t->t_dcom[1][0])) {
239 			if (t->t_dcom[2]) {
240 			    setname("nice");
241 			    t->t_nice = (unsigned char)getn(t->t_dcom[1]);
242 			    lshift(t->t_dcom, 2);
243 			    t->t_dflg |= F_NICE;
244 			}
245 			else
246 			    break;
247 		    }
248 		    else {
249 			t->t_nice = 4;
250 			lshift(t->t_dcom, 1);
251 			t->t_dflg |= F_NICE;
252 		    }
253 		}
254 		else
255 		    break;
256 	    }
257 	    else if (eq(t->t_dcom[0], STRnohup)) {
258 		if (t->t_dcom[1]) {
259 		    t->t_dflg |= F_NOHUP;
260 		    lshift(t->t_dcom, 1);
261 		}
262 		else
263 		    break;
264 	    }
265 	    else if (eq(t->t_dcom[0], STRhup)) {
266 		if (t->t_dcom[1]) {
267 		    t->t_dflg |= F_HUP;
268 		    lshift(t->t_dcom, 1);
269 		}
270 		else
271 		    break;
272 	    }
273 	    else if (eq(t->t_dcom[0], STRtime)) {
274 		if (t->t_dcom[1]) {
275 		    t->t_dflg |= F_TIME;
276 		    lshift(t->t_dcom, 1);
277 		}
278 		else
279 		    break;
280 	    }
281 #ifdef F_VER
282 	    else if (eq(t->t_dcom[0], STRver))
283 		if (t->t_dcom[1] && t->t_dcom[2]) {
284 		    setname("ver");
285 		    t->t_systype = getv(t->t_dcom[1]);
286 		    lshift(t->t_dcom, 2);
287 		    t->t_dflg |= F_VER;
288 		}
289 		else
290 		    break;
291 #endif  /* F_VER */
292 	    else
293 		break;
294 
295 	/* is it a command */
296 	if (t->t_dtyp == NODE_COMMAND) {
297 	    /*
298 	     * Check if we have a builtin function and remember which one.
299 	     */
300 	    bifunc = isbfunc(t);
301  	    if (noexec) {
302 		/*
303 		 * Continue for builtins that are part of the scripting language
304 		 */
305 		if (bifunc == NULL)
306 		    break;
307 		if (bifunc->bfunct != (bfunc_t)dobreak	&&
308 		    bifunc->bfunct != (bfunc_t)docontin	&&
309 		    bifunc->bfunct != (bfunc_t)doelse	&&
310 		    bifunc->bfunct != (bfunc_t)doend	&&
311 		    bifunc->bfunct != (bfunc_t)doforeach&&
312 		    bifunc->bfunct != (bfunc_t)dogoto	&&
313 		    bifunc->bfunct != (bfunc_t)doif	&&
314 		    bifunc->bfunct != (bfunc_t)dorepeat	&&
315 		    bifunc->bfunct != (bfunc_t)doswbrk	&&
316 		    bifunc->bfunct != (bfunc_t)doswitch	&&
317 		    bifunc->bfunct != (bfunc_t)dowhile	&&
318 		    bifunc->bfunct != (bfunc_t)dozip)
319 		    break;
320 	    }
321 	}
322 	else {			/* not a command */
323 	    bifunc = NULL;
324 	    if (noexec)
325 		break;
326 	}
327 
328 	/*
329 	 * GrP Executing a command - run jobcmd hook
330 	 * Don't run for builtins
331 	 * Don't run if we're not in a tty
332 	 * Don't run if we're not really executing
333 	 */
334 	/*
335 	 * CR  -  Charles Ross Aug 2005
336 	 * added "isoutatty".
337 	 * The new behavior is that the jobcmd won't be executed
338 	 * if stdout (SHOUT) isnt attached to a tty.. IE when
339 	 * redirecting, or using backquotes etc..
340 	 */
341 	if (t->t_dtyp == NODE_COMMAND && !bifunc && !noexec && intty && isoutatty) {
342 	    Char *cmd = unparse(t);
343 
344 	    cleanup_push(cmd, xfree);
345 	    job_cmd(cmd);
346 	    cleanup_until(cmd);
347 	}
348 
349 	/*
350 	 * We fork only if we are timed, or are not the end of a parenthesized
351 	 * list and not a simple builtin function. Simple meaning one that is
352 	 * not pipedout, niced, nohupped, or &'d. It would be nice(?) to not
353 	 * fork in some of these cases.
354 	 */
355 #ifdef BACKPIPE
356 	/*
357 	 * Can't have NOFORK for the tail of a pipe - because it is not the
358 	 * last command spawned (even if it is at the end of a parenthesised
359 	 * list).
360 	 */
361 	if (t->t_dflg & F_PIPEIN)
362 	    t->t_dflg &= ~(F_NOFORK);
363 #else
364 	/*
365 	 * "command | builtin" may cause major misbehaviour as noted in
366 	 * in the BUGS file entry
367 	 * Subject: Redirected input to built-in functions misbehaves badly
368 	 * forking when the builtin is the end of the pipe corrects the
369 	 * problem.
370 	 */
371 	if (bifunc && (t->t_dflg & F_PIPEIN))
372 	    t->t_dflg &= ~(F_NOFORK);
373 #endif /* BACKPIPE */
374 	/*
375 	 * Prevent forking cd, pushd, popd, chdir cause this will cause the
376 	 * shell not to change dir! (XXX: but only for nice?)
377 	 */
378 	if (bifunc && (bifunc->bfunct == (bfunc_t)dochngd ||
379 		       bifunc->bfunct == (bfunc_t)dopushd ||
380 		       bifunc->bfunct == (bfunc_t)dopopd))
381 	    t->t_dflg &= ~(F_NICE);
382 
383 	if (((t->t_dflg & F_TIME) || ((t->t_dflg & F_NOFORK) == 0 &&
384 	     (!bifunc || t->t_dflg &
385 	      (F_PIPEOUT | F_AMPERSAND | F_NICE | F_NOHUP | F_HUP)))) ||
386 	/*
387 	 * We have to fork for eval too.
388 	 */
389 	    (bifunc && (t->t_dflg & F_PIPEIN) != 0 &&
390 	     bifunc->bfunct == (bfunc_t)doeval)) {
391 #ifdef VFORK
392 	    if (t->t_dtyp == NODE_PAREN ||
393 		t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc)
394 #endif /* VFORK */
395 	    {
396 		forked++;
397 		/*
398 		 * We need to block SIGCHLD here, so that if the process does
399 		 * not die before we can set the process group
400 		 */
401 		if (wanttty >= 0 && !nosigchld) {
402 		    sigemptyset(&set);
403 		    sigaddset(&set, SIGCHLD);
404 		    (void)sigprocmask(SIG_BLOCK, &set, &csigset);
405 
406 		    nosigchld = 1;
407 		}
408 
409 		pid = pfork(t, wanttty);
410 		if (pid == 0 && nosigchld) {
411 		    sigprocmask(SIG_SETMASK, &csigset, NULL);
412 		    nosigchld = 0;
413 		}
414 		else if (pid != 0 && (t->t_dflg & F_AMPERSAND))
415 		    backpid = pid;
416 	    }
417 
418 #ifdef VFORK
419 	    else {
420 		int     ochild, osetintr, ohaderr, odidfds;
421 		int     oSHIN, oSHOUT, oSHDIAG, oOLDSTD, otpgrp;
422 		int     oisoutatty, oisdiagatty;
423 		sigset_t oset, ocsigset;
424 # ifndef CLOSE_ON_EXEC
425 		int     odidcch;
426 # endif  /* !CLOSE_ON_EXEC */
427 
428 		/*
429 		 * Prepare for the vfork by saving everything that the child
430 		 * corrupts before it exec's. Note that in some signal
431 		 * implementations which keep the signal info in user space
432 		 * (e.g. Sun's) it will also be necessary to save and restore
433 		 * the current sigvec's for the signals the child touches
434 		 * before it exec's.
435 		 */
436 
437 		/*
438 		 * Sooooo true... If this is a Sun, save the sigvec's. (Skip
439 		 * Gilbrech - 11/22/87)
440 		 */
441 # ifdef SAVESIGVEC
442 		struct sigaction savesv[NSIGSAVED];
443 		sigset_t savesm;
444 
445 # endif /* SAVESIGVEC */
446 		if (wanttty >= 0 && !nosigchld && !noexec) {
447 		    sigemptyset(&set);
448 		    sigaddset(&set, SIGCHLD);
449 		    (void)sigprocmask(SIG_BLOCK, &set, &csigset);
450 		    nosigchld = 1;
451 		}
452 		sigemptyset(&set);
453 		sigaddset(&set, SIGCHLD);
454 		sigaddset(&set, SIGINT);
455 		(void)sigprocmask(SIG_BLOCK, &set, &oset);
456 		ochild = child;
457 		osetintr = setintr;
458 		ohaderr = haderr;
459 		odidfds = didfds;
460 # ifndef CLOSE_ON_EXEC
461 		odidcch = didcch;
462 # endif /* !CLOSE_ON_EXEC */
463 		oSHIN = SHIN;
464 		oSHOUT = SHOUT;
465 		oSHDIAG = SHDIAG;
466 		oOLDSTD = OLDSTD;
467 		otpgrp = tpgrp;
468 		oisoutatty = isoutatty;
469 		oisdiagatty = isdiagatty;
470 		ocsigset = csigset;
471 		onosigchld = nosigchld;
472 		Vsav = Vdp = 0;
473 		Vexpath = 0;
474 		Vt = 0;
475 # ifdef SAVESIGVEC
476 		savesigvec(savesv, savesm);
477 # endif /* SAVESIGVEC */
478 		if (use_fork)
479 		    pid = fork();
480 		else
481 		    pid = vfork();
482 
483 		if (pid < 0) {
484 # ifdef SAVESIGVEC
485 		    restoresigvec(savesv, savesm);
486 # endif /* SAVESIGVEC */
487 		    sigprocmask(SIG_SETMASK, &oset, NULL);
488 		    stderror(ERR_NOPROC);
489 		}
490 		forked++;
491 		if (pid) {	/* parent */
492 # ifdef SAVESIGVEC
493 		    restoresigvec(savesv, savesm);
494 # endif /* SAVESIGVEC */
495 		    child = ochild;
496 		    setintr = osetintr;
497 		    haderr = ohaderr;
498 		    didfds = odidfds;
499 		    SHIN = oSHIN;
500 # ifndef CLOSE_ON_EXEC
501 		    didcch = odidcch;
502 # endif /* !CLOSE_ON_EXEC */
503 		    SHOUT = oSHOUT;
504 		    SHDIAG = oSHDIAG;
505 		    OLDSTD = oOLDSTD;
506 		    tpgrp = otpgrp;
507 		    isoutatty = oisoutatty;
508 		    isdiagatty = oisdiagatty;
509 		    csigset = ocsigset;
510 		    nosigchld = onosigchld;
511 
512 		    xfree(Vsav);
513 		    Vsav = 0;
514 		    xfree(Vdp);
515 		    Vdp = 0;
516 		    xfree(Vexpath);
517 		    Vexpath = 0;
518 		    blk_cleanup(Vt);
519 		    Vt = 0;
520 		    /* this is from pfork() */
521 		    palloc(pid, t);
522 		    sigprocmask(SIG_SETMASK, &oset, NULL);
523 		}
524 		else {		/* child */
525 		    /* this is from pfork() */
526 		    pid_t pgrp;
527 		    int    ignint = 0;
528 		    if (nosigchld) {
529 			sigprocmask(SIG_SETMASK, &csigset, NULL);
530 			nosigchld = 0;
531 		    }
532 
533 		    if (setintr)
534 			ignint = (tpgrp == -1 && (t->t_dflg & F_NOINTERRUPT))
535 				|| (gointr && eq(gointr, STRminus));
536 		    pgrp = pcurrjob ? pcurrjob->p_jobid : getpid();
537 		    child++;
538 		    if (setintr) {
539 			setintr = 0;
540 /*
541  * casts made right for SunOS 4.0 by Douglas C. Schmidt
542  * <schmidt%sunshine.ics.uci.edu@ROME.ICS.UCI.EDU>
543  * (thanks! -- PWP)
544  *
545  * ignint ifs cleaned by Johan Widen <mcvax!osiris.sics.se!jw@uunet.UU.NET>
546  * (thanks again)
547  */
548 			if (ignint) {
549 			    (void) signal(SIGINT, SIG_IGN);
550 			    (void) signal(SIGQUIT, SIG_IGN);
551 			}
552 			else {
553 			    (void) signal(SIGINT, vffree);
554 			    (void) signal(SIGQUIT, SIG_DFL);
555 			}
556 # ifdef BSDJOBS
557 			if (wanttty >= 0) {
558 			    (void) signal(SIGTSTP, SIG_DFL);
559 			    (void) signal(SIGTTIN, SIG_DFL);
560 			    (void) signal(SIGTTOU, SIG_DFL);
561 			}
562 # endif /* BSDJOBS */
563 
564 			sigaction(SIGTERM, &parterm, NULL);
565 		    }
566 		    else if (tpgrp == -1 &&
567 			     (t->t_dflg & F_NOINTERRUPT)) {
568 			(void) signal(SIGINT, SIG_IGN);
569 			(void) signal(SIGQUIT, SIG_IGN);
570 		    }
571 
572 		    pgetty(wanttty, pgrp);
573 
574 		    if (t->t_dflg & F_NOHUP)
575 			(void) signal(SIGHUP, SIG_IGN);
576 		    if (t->t_dflg & F_HUP)
577 			(void) signal(SIGHUP, SIG_DFL);
578 		    if (t->t_dflg & F_NICE) {
579 			int nval = SIGN_EXTEND_CHAR(t->t_nice);
580 # if defined(HAVE_SETPRIORITY) && defined(PRIO_PROCESS)
581 			if (setpriority(PRIO_PROCESS, 0, nval) == -1 && errno)
582 				stderror(ERR_SYSTEM, "setpriority",
583 				    strerror(errno));
584 # else /* !HAVE_SETPRIORITY || !PRIO_PROCESS */
585 			(void) nice(nval);
586 # endif /* HAVE_SETPRIORITY && PRIO_PROCESS */
587 		    }
588 # ifdef F_VER
589 		    if (t->t_dflg & F_VER) {
590 			tsetenv(STRSYSTYPE, t->t_systype ? STRbsd43 : STRsys53);
591 			dohash(NULL, NULL);
592 		    }
593 # endif /* F_VER */
594 		}
595 
596 	    }
597 #endif /* VFORK */
598 	}
599 	if (pid != 0) {
600 	    /*
601 	     * It would be better if we could wait for the whole job when we
602 	     * knew the last process had been started.  Pwait, in fact, does
603 	     * wait for the whole job anyway, but this test doesn't really
604 	     * express our intentions.
605 	     */
606 #ifdef BACKPIPE
607 	    if (didfds == 0 && t->t_dflg & F_PIPEOUT) {
608 		xclose(pipeout[0]);
609 		xclose(pipeout[1]);
610 	    }
611 	    if ((t->t_dflg & F_PIPEIN) != 0)
612 		break;
613 #else /* !BACKPIPE */
614 	    if (didfds == 0 && t->t_dflg & F_PIPEIN) {
615 		xclose(pipein[0]);
616 		xclose(pipein[1]);
617 	    }
618 	    if ((t->t_dflg & F_PIPEOUT) != 0)
619 		break;
620 #endif /* BACKPIPE */
621 
622 	    if (nosigchld) {
623 		sigprocmask(SIG_SETMASK, &csigset, NULL);
624 		nosigchld = 0;
625 	    }
626 	    if ((t->t_dflg & F_AMPERSAND) == 0)
627 		pwait();
628 	    break;
629 	}
630 
631 	doio(t, pipein, pipeout);
632 #ifdef BACKPIPE
633 	if (t->t_dflg & F_PIPEIN) {
634 	    xclose(pipein[0]);
635 	    xclose(pipein[1]);
636 	}
637 #else /* !BACKPIPE */
638 	if (t->t_dflg & F_PIPEOUT) {
639 	    xclose(pipeout[0]);
640 	    xclose(pipeout[1]);
641 	}
642 #endif /* BACKPIPE */
643 	/*
644 	 * Perform a builtin function. If we are not forked, arrange for
645 	 * possible stopping
646 	 */
647 	if (bifunc) {
648 	    if (forked) {
649 		func(t, bifunc);
650 		exitstat();
651 	    } else {
652 		jmp_buf_t oldexit;
653 		int ohaderr = haderr;
654 
655 		getexit(oldexit);
656 		if (setexit() == 0)
657 		    func(t, bifunc);
658 		resexit(oldexit);
659 		haderr = ohaderr;
660 
661 		if (adrof(STRprintexitvalue)) {
662 		    int rv = getn(varval(STRstatus));
663 		    if (rv != 0)
664 			xprintf(CGETS(17, 2, "Exit %d\n"), rv);
665 		}
666 	    }
667 	    break;
668 	}
669 	if (t->t_dtyp != NODE_PAREN) {
670 	    doexec(t, do_glob);
671 	    /* NOTREACHED */
672 	}
673 	/*
674 	 * For () commands must put new 0,1,2 in FSH* and recurse
675 	 */
676 	if ((OLDSTD = dcopy(0, FOLDSTD)) >= 0)
677 	    (void)close_on_exec(OLDSTD, 1);
678 	if ((SHOUT = dcopy(1, FSHOUT)) >= 0) {
679 	    (void)close_on_exec(SHOUT, 1);
680 	    isoutatty = isatty(SHOUT);
681 	}
682 	if ((SHDIAG = dcopy(2, FSHDIAG)) >= 0) {
683 	    (void)close_on_exec(SHDIAG, 1);
684 	    isdiagatty = isatty(SHDIAG);
685     	}
686 	xclose(SHIN);
687 	SHIN = -1;
688 #ifndef CLOSE_ON_EXEC
689 	didcch = 0;
690 #else
691 	(void) close_on_exec(FSHOUT, 1);
692 	(void) close_on_exec(FSHDIAG, 1);
693 	(void) close_on_exec(FOLDSTD, 1);
694 #endif /* !CLOSE_ON_EXEC */
695 	didfds = 0;
696 	wanttty = -1;
697 	t->t_dspr->t_dflg |= t->t_dflg & (F_NOINTERRUPT | F_BACKQ);
698 	execute(t->t_dspr, wanttty, NULL, NULL, do_glob);
699 	exitstat();
700 
701     case NODE_PIPE:
702 #ifdef BACKPIPE
703 	t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg &
704 	    (F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT | F_BACKQ));
705 	execute(t->t_dcdr, wanttty, pv, pipeout, do_glob);
706 	t->t_dcar->t_dflg |= F_PIPEOUT | (t->t_dflg &
707 	    (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT | F_BACKQ));
708 	execute(t->t_dcar, wanttty, pipein, pv, do_glob);
709 #else /* !BACKPIPE */
710 	t->t_dcar->t_dflg |= F_PIPEOUT | (t->t_dflg &
711 	    (F_PIPEIN | F_AMPERSAND | F_STDERR | F_NOINTERRUPT | F_BACKQ));
712 	execute(t->t_dcar, wanttty, pipein, pv, do_glob);
713 	t->t_dcdr->t_dflg |= F_PIPEIN | (t->t_dflg &
714 	    (F_PIPEOUT | F_AMPERSAND | F_NOFORK | F_NOINTERRUPT | F_BACKQ));
715 	execute(t->t_dcdr, wanttty, pv, pipeout, do_glob);
716 #endif /* BACKPIPE */
717 	break;
718 
719     case NODE_LIST:
720 	if (t->t_dcar) {
721 	    t->t_dcar->t_dflg |= t->t_dflg & (F_NOINTERRUPT | F_BACKQ);
722 	    execute(t->t_dcar, wanttty, NULL, NULL, do_glob);
723 	    /*
724 	     * In strange case of A&B make a new job after A
725 	     */
726 	    if (t->t_dcar->t_dflg & F_AMPERSAND && t->t_dcdr &&
727 		(t->t_dcdr->t_dflg & F_AMPERSAND) == 0)
728 		pendjob();
729 	}
730 	if (t->t_dcdr) {
731 	    t->t_dcdr->t_dflg |= t->t_dflg &
732 		(F_NOFORK | F_NOINTERRUPT | F_BACKQ);
733 	    execute(t->t_dcdr, wanttty, NULL, NULL, do_glob);
734 	}
735 	break;
736 
737     case NODE_OR:
738     case NODE_AND:
739 	if (t->t_dcar) {
740 	    t->t_dcar->t_dflg |= t->t_dflg & (F_NOINTERRUPT | F_BACKQ);
741 	    execute(t->t_dcar, wanttty, NULL, NULL, do_glob);
742 	    if ((getn(varval(STRstatus)) == 0) !=
743 		(t->t_dtyp == NODE_AND)) {
744 		return;
745 	    }
746 	}
747 	if (t->t_dcdr) {
748 	    t->t_dcdr->t_dflg |= t->t_dflg &
749 		(F_NOFORK | F_NOINTERRUPT | F_BACKQ);
750 	    execute(t->t_dcdr, wanttty, NULL, NULL, do_glob);
751 	}
752 	break;
753 
754     default:
755 	break;
756     }
757     /*
758      * Fall through for all breaks from switch
759      *
760      * If there will be no more executions of this command, flush all file
761      * descriptors. Places that turn on the F_REPEAT bit are responsible for
762      * doing donefds after the last re-execution
763      */
764     if (didfds && !(t->t_dflg & F_REPEAT))
765 	donefds();
766 }
767 
768 #ifdef VFORK
769 static void
770 /*ARGSUSED*/
771 vffree(int snum)
772 {
773     USE(snum);
774 
775     _exit(1);
776 }
777 #endif /* VFORK */
778 
779 /*
780  * Expand and glob the words after an i/o redirection.
781  * If more than one word is generated, then update the command vector.
782  *
783  * This is done differently in all the shells:
784  * 1. in the bourne shell and ksh globbing is not performed
785  * 2. Bash/csh say ambiguous
786  * 3. zsh does i/o to/from all the files
787  * 4. itcsh concatenates the words.
788  *
789  * I don't know what is best to do. I think that Ambiguous is better
790  * than restructuring the command vector, because the user can get
791  * unexpected results. In any case, the command vector restructuring
792  * code is present and the user can choose it by setting noambiguous
793  */
794 static Char *
795 splicepipe(struct command *t, Char *cp)
796 {
797     Char *blk[2];
798 
799     if (adrof(STRnoambiguous)) {
800 	Char **pv;
801 	int gflag;
802 
803 	blk[0] = Dfix1(cp); /* expand $ */
804 	blk[1] = NULL;
805 
806 	gflag = tglob(blk);
807 	if (gflag) {
808 	    pv = globall(blk, gflag);
809 	    if (pv == NULL) {
810 		setname(short2str(blk[0]));
811 		xfree(blk[0]);
812 		stderror(ERR_NAME | ERR_NOMATCH);
813 	    }
814 	    if (pv[1] != NULL) { /* we need to fix the command vector */
815 		Char **av = blkspl(t->t_dcom, &pv[1]);
816 		xfree(t->t_dcom);
817 		t->t_dcom = av;
818 	    }
819 	    xfree(blk[0]);
820 	    blk[0] = pv[0];
821 	    xfree(pv);
822 	}
823     }
824     else {
825 	Char *buf;
826 
827 	buf = Dfix1(cp);
828 	cleanup_push(buf, xfree);
829 	blk[0] = globone(buf, G_ERROR);
830 	cleanup_until(buf);
831     }
832     return(blk[0]);
833 }
834 
835 /*
836  * Perform io redirection.
837  * We may or maynot be forked here.
838  */
839 static void
840 doio(struct command *t, int *pipein, int *pipeout)
841 {
842     int fd;
843     Char *cp;
844     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;
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 	    tmp = strsave(short2str(cp));
860 	    xfree(cp);
861 	    cleanup_push(tmp, xfree);
862 	    if ((fd = xopen(tmp, O_RDONLY|O_LARGEFILE)) < 0)
863 		stderror(ERR_SYSTEM, tmp, strerror(errno));
864 	    cleanup_until(tmp);
865 	    /* allow input files larger than 2Gb  */
866 #ifndef WINNT_NATIVE
867 	    (void) fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_LARGEFILE);
868 #endif /*!WINNT_NATIVE*/
869 	    (void) dmove(fd, 0);
870 	}
871 	else if (flags & F_PIPEIN) {
872 	    xclose(0);
873 	    TCSH_IGNORE(dup(pipein[0]));
874 	    xclose(pipein[0]);
875 	    xclose(pipein[1]);
876 	}
877 	else if ((flags & F_NOINTERRUPT) && tpgrp == -1) {
878 	    xclose(0);
879 	    (void) xopen(_PATH_DEVNULL, O_RDONLY|O_LARGEFILE);
880 	}
881 	else {
882 	    xclose(0);
883 	    TCSH_IGNORE(dup(OLDSTD));
884 #if defined(CLOSE_ON_EXEC) && defined(CLEX_DUPS)
885 	    /*
886 	     * PWP: Unlike Bezerkeley 4.3, FIONCLEX for Pyramid is preserved
887 	     * across dup()s, so we have to UNSET it here or else we get a
888 	     * command with NO stdin, stdout, or stderr at all (a bad thing
889 	     * indeed)
890 	     */
891 	    (void) close_on_exec(0, 0);
892 #endif /* CLOSE_ON_EXEC && CLEX_DUPS */
893 	}
894     }
895     if (t->t_drit) {
896 	char *tmp;
897 
898 	cp = splicepipe(t, t->t_drit);
899 	tmp = strsave(short2str(cp));
900 	xfree(cp);
901 	cleanup_push(tmp, xfree);
902 	/*
903 	 * so > /dev/std{out,err} work
904 	 */
905 	(void) dcopy(SHOUT, 1);
906 	(void) dcopy(SHDIAG, 2);
907 	if ((flags & F_APPEND) != 0) {
908 #ifdef O_APPEND
909 	    fd = xopen(tmp, O_WRONLY|O_APPEND|O_LARGEFILE);
910 #else /* !O_APPEND */
911 	    fd = xopen(tmp, O_WRONLY|O_LARGEFILE);
912 	    (void) lseek(fd, (off_t) 0, L_XTND);
913 #endif /* O_APPEND */
914 	}
915 	else
916 	    fd = 0;
917 	if ((flags & F_APPEND) == 0 || fd == -1) {
918 	    if (!(flags & F_OVERWRITE) && no_clobber) {
919 		if (flags & F_APPEND)
920 		    stderror(ERR_SYSTEM, tmp, strerror(errno));
921 		chkclob(tmp);
922 	    }
923 	    if ((fd = xcreat(tmp, 0666)) < 0)
924 		stderror(ERR_SYSTEM, tmp, strerror(errno));
925 	    /* allow input files larger than 2Gb  */
926 #ifndef WINNT_NATIVE
927 	    (void) fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_LARGEFILE);
928 #endif /*!WINNT_NATIVE*/
929 	}
930 	cleanup_until(tmp);
931 	(void) dmove(fd, 1);
932 	is1atty = isatty(1);
933     }
934     else if (flags & F_PIPEOUT) {
935 	xclose(1);
936 	TCSH_IGNORE(dup(pipeout[1]));
937 	is1atty = 0;
938     }
939     else {
940 	xclose(1);
941 	TCSH_IGNORE(dup(SHOUT));
942 	is1atty = isoutatty;
943 # if defined(CLOSE_ON_EXEC) && defined(CLEX_DUPS)
944 	(void) close_on_exec(1, 0);
945 # endif /* CLOSE_ON_EXEC && CLEX_DUPS */
946     }
947 
948     xclose(2);
949     if (flags & F_STDERR) {
950 	TCSH_IGNORE(dup(1));
951 	is2atty = is1atty;
952     }
953     else {
954 	TCSH_IGNORE(dup(SHDIAG));
955 	is2atty = isdiagatty;
956 # if defined(CLOSE_ON_EXEC) && defined(CLEX_DUPS)
957 	(void) close_on_exec(2, 0);
958 # endif /* CLOSE_ON_EXEC && CLEX_DUPS */
959     }
960     didfds = 1;
961 }
962 
963 void
964 mypipe(int *pv)
965 {
966 
967     if (pipe(pv) < 0)
968 	goto oops;
969     (void)close_on_exec(pv[0] = dmove(pv[0], -1), 1);
970     (void)close_on_exec(pv[1] = dmove(pv[1], -1), 1);
971     if (pv[0] >= 0 && pv[1] >= 0)
972 	return;
973     if (pv[0] >= 0)
974 	xclose(pv[0]);
975     if (pv[1] >= 0)
976 	xclose(pv[1]);
977 oops:
978     stderror(ERR_PIPE);
979 }
980 
981 static void
982 chkclob(const char *cp)
983 {
984     struct stat stb;
985 
986     if (stat(cp, &stb) < 0)
987 	return;
988     if (S_ISCHR(stb.st_mode))
989 	return;
990     if (no_clobber & NOCLOBBER_NOTEMPTY && stb.st_size == 0)
991 	return;
992     if (no_clobber & NOCLOBBER_ASK) {
993 	if (getYN(CGETS(22, 15,
994 	    "Do you really want to overwrite an existing file? [N/y] ")))
995 	    return;
996     }
997 
998     stderror(ERR_EXISTS, cp);
999 }
1000