eval.c revision 204802 
1/*-
2 * Copyright (c) 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34#if 0
35static char sccsid[] = "@(#)eval.c	8.9 (Berkeley) 6/8/95";
36#endif
37#endif /* not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: head/bin/sh/eval.c 204802 2010-03-06 17:31:09Z jilles $");
40
41#include <paths.h>
42#include <signal.h>
43#include <stdlib.h>
44#include <unistd.h>
45#include <sys/resource.h>
46#include <sys/wait.h> /* For WIFSIGNALED(status) */
47#include <errno.h>
48
49/*
50 * Evaluate a command.
51 */
52
53#include "shell.h"
54#include "nodes.h"
55#include "syntax.h"
56#include "expand.h"
57#include "parser.h"
58#include "jobs.h"
59#include "eval.h"
60#include "builtins.h"
61#include "options.h"
62#include "exec.h"
63#include "redir.h"
64#include "input.h"
65#include "output.h"
66#include "trap.h"
67#include "var.h"
68#include "memalloc.h"
69#include "error.h"
70#include "show.h"
71#include "mystring.h"
72#ifndef NO_HISTORY
73#include "myhistedit.h"
74#endif
75
76
77int evalskip;			/* set if we are skipping commands */
78STATIC int skipcount;		/* number of levels to skip */
79MKINIT int loopnest;		/* current loop nesting level */
80int funcnest;			/* depth of function calls */
81STATIC int builtin_flags;	/* evalcommand flags for builtins */
82
83
84char *commandname;
85struct strlist *cmdenviron;
86int exitstatus;			/* exit status of last command */
87int oexitstatus;		/* saved exit status */
88
89
90STATIC void evalloop(union node *, int);
91STATIC void evalfor(union node *, int);
92STATIC void evalcase(union node *, int);
93STATIC void evalsubshell(union node *, int);
94STATIC void expredir(union node *);
95STATIC void evalpipe(union node *);
96STATIC void evalcommand(union node *, int, struct backcmd *);
97STATIC void prehash(union node *);
98
99
100/*
101 * Called to reset things after an exception.
102 */
103
104#ifdef mkinit
105INCLUDE "eval.h"
106
107RESET {
108	evalskip = 0;
109	loopnest = 0;
110	funcnest = 0;
111}
112
113SHELLPROC {
114	exitstatus = 0;
115}
116#endif
117
118
119
120/*
121 * The eval command.
122 */
123
124int
125evalcmd(int argc, char **argv)
126{
127        char *p;
128        char *concat;
129        char **ap;
130
131        if (argc > 1) {
132                p = argv[1];
133                if (argc > 2) {
134                        STARTSTACKSTR(concat);
135                        ap = argv + 2;
136                        for (;;) {
137                                while (*p)
138                                        STPUTC(*p++, concat);
139                                if ((p = *ap++) == NULL)
140                                        break;
141                                STPUTC(' ', concat);
142                        }
143                        STPUTC('\0', concat);
144                        p = grabstackstr(concat);
145                }
146                evalstring(p, builtin_flags & EV_TESTED);
147        }
148        return exitstatus;
149}
150
151
152/*
153 * Execute a command or commands contained in a string.
154 */
155
156void
157evalstring(char *s, int flags)
158{
159	union node *n;
160	struct stackmark smark;
161	int flags_exit;
162
163	flags_exit = flags & EV_EXIT;
164	flags &= ~EV_EXIT;
165	setstackmark(&smark);
166	setinputstring(s, 1);
167	while ((n = parsecmd(0)) != NEOF) {
168		if (n != NULL) {
169			if (flags_exit && preadateof())
170				evaltree(n, flags | EV_EXIT);
171			else
172				evaltree(n, flags);
173		}
174		popstackmark(&smark);
175	}
176	popfile();
177	popstackmark(&smark);
178	if (flags_exit)
179		exitshell(exitstatus);
180}
181
182
183/*
184 * Evaluate a parse tree.  The value is left in the global variable
185 * exitstatus.
186 */
187
188void
189evaltree(union node *n, int flags)
190{
191	int do_etest;
192
193	do_etest = 0;
194	if (n == NULL) {
195		TRACE(("evaltree(NULL) called\n"));
196		exitstatus = 0;
197		goto out;
198	}
199#ifndef NO_HISTORY
200	displayhist = 1;	/* show history substitutions done with fc */
201#endif
202	TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
203	switch (n->type) {
204	case NSEMI:
205		evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
206		if (evalskip)
207			goto out;
208		evaltree(n->nbinary.ch2, flags);
209		break;
210	case NAND:
211		evaltree(n->nbinary.ch1, EV_TESTED);
212		if (evalskip || exitstatus != 0) {
213			goto out;
214		}
215		evaltree(n->nbinary.ch2, flags);
216		break;
217	case NOR:
218		evaltree(n->nbinary.ch1, EV_TESTED);
219		if (evalskip || exitstatus == 0)
220			goto out;
221		evaltree(n->nbinary.ch2, flags);
222		break;
223	case NREDIR:
224		expredir(n->nredir.redirect);
225		redirect(n->nredir.redirect, REDIR_PUSH);
226		evaltree(n->nredir.n, flags);
227		popredir();
228		break;
229	case NSUBSHELL:
230		evalsubshell(n, flags);
231		do_etest = !(flags & EV_TESTED);
232		break;
233	case NBACKGND:
234		evalsubshell(n, flags);
235		break;
236	case NIF: {
237		evaltree(n->nif.test, EV_TESTED);
238		if (evalskip)
239			goto out;
240		if (exitstatus == 0)
241			evaltree(n->nif.ifpart, flags);
242		else if (n->nif.elsepart)
243			evaltree(n->nif.elsepart, flags);
244		else
245			exitstatus = 0;
246		break;
247	}
248	case NWHILE:
249	case NUNTIL:
250		evalloop(n, flags & ~EV_EXIT);
251		break;
252	case NFOR:
253		evalfor(n, flags & ~EV_EXIT);
254		break;
255	case NCASE:
256		evalcase(n, flags);
257		break;
258	case NDEFUN:
259		defun(n->narg.text, n->narg.next);
260		exitstatus = 0;
261		break;
262	case NNOT:
263		evaltree(n->nnot.com, EV_TESTED);
264		exitstatus = !exitstatus;
265		break;
266
267	case NPIPE:
268		evalpipe(n);
269		do_etest = !(flags & EV_TESTED);
270		break;
271	case NCMD:
272		evalcommand(n, flags, (struct backcmd *)NULL);
273		do_etest = !(flags & EV_TESTED);
274		break;
275	default:
276		out1fmt("Node type = %d\n", n->type);
277		flushout(&output);
278		break;
279	}
280out:
281	if (pendingsigs)
282		dotrap();
283	if ((flags & EV_EXIT) || (eflag && exitstatus != 0 && do_etest))
284		exitshell(exitstatus);
285}
286
287
288STATIC void
289evalloop(union node *n, int flags)
290{
291	int status;
292
293	loopnest++;
294	status = 0;
295	for (;;) {
296		evaltree(n->nbinary.ch1, EV_TESTED);
297		if (evalskip) {
298skipping:	  if (evalskip == SKIPCONT && --skipcount <= 0) {
299				evalskip = 0;
300				continue;
301			}
302			if (evalskip == SKIPBREAK && --skipcount <= 0)
303				evalskip = 0;
304			break;
305		}
306		if (n->type == NWHILE) {
307			if (exitstatus != 0)
308				break;
309		} else {
310			if (exitstatus == 0)
311				break;
312		}
313		evaltree(n->nbinary.ch2, flags);
314		status = exitstatus;
315		if (evalskip)
316			goto skipping;
317	}
318	loopnest--;
319	exitstatus = status;
320}
321
322
323
324STATIC void
325evalfor(union node *n, int flags)
326{
327	struct arglist arglist;
328	union node *argp;
329	struct strlist *sp;
330	struct stackmark smark;
331
332	setstackmark(&smark);
333	arglist.lastp = &arglist.list;
334	for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
335		oexitstatus = exitstatus;
336		expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
337		if (evalskip)
338			goto out;
339	}
340	*arglist.lastp = NULL;
341
342	exitstatus = 0;
343	loopnest++;
344	for (sp = arglist.list ; sp ; sp = sp->next) {
345		setvar(n->nfor.var, sp->text, 0);
346		evaltree(n->nfor.body, flags);
347		if (evalskip) {
348			if (evalskip == SKIPCONT && --skipcount <= 0) {
349				evalskip = 0;
350				continue;
351			}
352			if (evalskip == SKIPBREAK && --skipcount <= 0)
353				evalskip = 0;
354			break;
355		}
356	}
357	loopnest--;
358out:
359	popstackmark(&smark);
360}
361
362
363
364STATIC void
365evalcase(union node *n, int flags)
366{
367	union node *cp;
368	union node *patp;
369	struct arglist arglist;
370	struct stackmark smark;
371
372	setstackmark(&smark);
373	arglist.lastp = &arglist.list;
374	oexitstatus = exitstatus;
375	exitstatus = 0;
376	expandarg(n->ncase.expr, &arglist, EXP_TILDE);
377	for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) {
378		for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
379			if (casematch(patp, arglist.list->text)) {
380				if (evalskip == 0) {
381					evaltree(cp->nclist.body, flags);
382				}
383				goto out;
384			}
385		}
386	}
387out:
388	popstackmark(&smark);
389}
390
391
392
393/*
394 * Kick off a subshell to evaluate a tree.
395 */
396
397STATIC void
398evalsubshell(union node *n, int flags)
399{
400	struct job *jp;
401	int backgnd = (n->type == NBACKGND);
402
403	expredir(n->nredir.redirect);
404	if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
405			forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
406		if (backgnd)
407			flags &=~ EV_TESTED;
408		redirect(n->nredir.redirect, 0);
409		evaltree(n->nredir.n, flags | EV_EXIT);	/* never returns */
410	} else if (! backgnd) {
411		INTOFF;
412		exitstatus = waitforjob(jp, (int *)NULL);
413		INTON;
414	}
415}
416
417
418
419/*
420 * Compute the names of the files in a redirection list.
421 */
422
423STATIC void
424expredir(union node *n)
425{
426	union node *redir;
427
428	for (redir = n ; redir ; redir = redir->nfile.next) {
429		struct arglist fn;
430		fn.lastp = &fn.list;
431		oexitstatus = exitstatus;
432		switch (redir->type) {
433		case NFROM:
434		case NTO:
435		case NFROMTO:
436		case NAPPEND:
437		case NCLOBBER:
438			expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
439			redir->nfile.expfname = fn.list->text;
440			break;
441		case NFROMFD:
442		case NTOFD:
443			if (redir->ndup.vname) {
444				expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR);
445				fixredir(redir, fn.list->text, 1);
446			}
447			break;
448		}
449	}
450}
451
452
453
454/*
455 * Evaluate a pipeline.  All the processes in the pipeline are children
456 * of the process creating the pipeline.  (This differs from some versions
457 * of the shell, which make the last process in a pipeline the parent
458 * of all the rest.)
459 */
460
461STATIC void
462evalpipe(union node *n)
463{
464	struct job *jp;
465	struct nodelist *lp;
466	int pipelen;
467	int prevfd;
468	int pip[2];
469
470	TRACE(("evalpipe(%p) called\n", (void *)n));
471	pipelen = 0;
472	for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
473		pipelen++;
474	INTOFF;
475	jp = makejob(n, pipelen);
476	prevfd = -1;
477	for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
478		prehash(lp->n);
479		pip[1] = -1;
480		if (lp->next) {
481			if (pipe(pip) < 0) {
482				close(prevfd);
483				error("Pipe call failed: %s", strerror(errno));
484			}
485		}
486		if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
487			INTON;
488			if (prevfd > 0) {
489				dup2(prevfd, 0);
490				close(prevfd);
491			}
492			if (pip[1] >= 0) {
493				if (!(prevfd >= 0 && pip[0] == 0))
494					close(pip[0]);
495				if (pip[1] != 1) {
496					dup2(pip[1], 1);
497					close(pip[1]);
498				}
499			}
500			evaltree(lp->n, EV_EXIT);
501		}
502		if (prevfd >= 0)
503			close(prevfd);
504		prevfd = pip[0];
505		close(pip[1]);
506	}
507	INTON;
508	if (n->npipe.backgnd == 0) {
509		INTOFF;
510		exitstatus = waitforjob(jp, (int *)NULL);
511		TRACE(("evalpipe:  job done exit status %d\n", exitstatus));
512		INTON;
513	}
514}
515
516
517
518/*
519 * Execute a command inside back quotes.  If it's a builtin command, we
520 * want to save its output in a block obtained from malloc.  Otherwise
521 * we fork off a subprocess and get the output of the command via a pipe.
522 * Should be called with interrupts off.
523 */
524
525void
526evalbackcmd(union node *n, struct backcmd *result)
527{
528	int pip[2];
529	struct job *jp;
530	struct stackmark smark;		/* unnecessary */
531
532	setstackmark(&smark);
533	result->fd = -1;
534	result->buf = NULL;
535	result->nleft = 0;
536	result->jp = NULL;
537	if (n == NULL) {
538		exitstatus = 0;
539		goto out;
540	}
541	if (n->type == NCMD) {
542		exitstatus = oexitstatus;
543		evalcommand(n, EV_BACKCMD, result);
544	} else {
545		exitstatus = 0;
546		if (pipe(pip) < 0)
547			error("Pipe call failed: %s", strerror(errno));
548		jp = makejob(n, 1);
549		if (forkshell(jp, n, FORK_NOJOB) == 0) {
550			FORCEINTON;
551			close(pip[0]);
552			if (pip[1] != 1) {
553				dup2(pip[1], 1);
554				close(pip[1]);
555			}
556			evaltree(n, EV_EXIT);
557		}
558		close(pip[1]);
559		result->fd = pip[0];
560		result->jp = jp;
561	}
562out:
563	popstackmark(&smark);
564	TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
565		result->fd, result->buf, result->nleft, result->jp));
566}
567
568
569
570/*
571 * Execute a simple command.
572 */
573
574STATIC void
575evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
576{
577	struct stackmark smark;
578	union node *argp;
579	struct arglist arglist;
580	struct arglist varlist;
581	char **argv;
582	int argc;
583	char **envp;
584	int varflag;
585	struct strlist *sp;
586	int mode;
587	int pip[2];
588	struct cmdentry cmdentry;
589	struct job *jp;
590	struct jmploc jmploc;
591	struct jmploc *savehandler;
592	char *savecmdname;
593	struct shparam saveparam;
594	struct localvar *savelocalvars;
595	struct parsefile *savetopfile;
596	volatile int e;
597	char *lastarg;
598	int realstatus;
599	int do_clearcmdentry;
600	char *path = pathval();
601
602	/* First expand the arguments. */
603	TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
604	setstackmark(&smark);
605	arglist.lastp = &arglist.list;
606	varlist.lastp = &varlist.list;
607	varflag = 1;
608	do_clearcmdentry = 0;
609	oexitstatus = exitstatus;
610	exitstatus = 0;
611	for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
612		char *p = argp->narg.text;
613		if (varflag && is_name(*p)) {
614			do {
615				p++;
616			} while (is_in_name(*p));
617			if (*p == '=') {
618				expandarg(argp, &varlist, EXP_VARTILDE);
619				continue;
620			}
621		}
622		expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
623		varflag = 0;
624	}
625	*arglist.lastp = NULL;
626	*varlist.lastp = NULL;
627	expredir(cmd->ncmd.redirect);
628	argc = 0;
629	for (sp = arglist.list ; sp ; sp = sp->next)
630		argc++;
631	argv = stalloc(sizeof (char *) * (argc + 1));
632
633	for (sp = arglist.list ; sp ; sp = sp->next) {
634		TRACE(("evalcommand arg: %s\n", sp->text));
635		*argv++ = sp->text;
636	}
637	*argv = NULL;
638	lastarg = NULL;
639	if (iflag && funcnest == 0 && argc > 0)
640		lastarg = argv[-1];
641	argv -= argc;
642
643	/* Print the command if xflag is set. */
644	if (xflag) {
645		char sep = 0;
646		const char *p;
647		out2str(ps4val());
648		for (sp = varlist.list ; sp ; sp = sp->next) {
649			if (sep != 0)
650				out2c(' ');
651			p = sp->text;
652			while (*p != '=' && *p != '\0')
653				out2c(*p++);
654			if (*p != '\0') {
655				out2c(*p++);
656				out2qstr(p);
657			}
658			sep = ' ';
659		}
660		for (sp = arglist.list ; sp ; sp = sp->next) {
661			if (sep != 0)
662				out2c(' ');
663			/* Disambiguate command looking like assignment. */
664			if (sp == arglist.list &&
665					strchr(sp->text, '=') != NULL &&
666					strchr(sp->text, '\'') == NULL) {
667				out2c('\'');
668				out2str(sp->text);
669				out2c('\'');
670			} else
671				out2qstr(sp->text);
672			sep = ' ';
673		}
674		out2c('\n');
675		flushout(&errout);
676	}
677
678	/* Now locate the command. */
679	if (argc == 0) {
680		/* Variable assignment(s) without command */
681		cmdentry.cmdtype = CMDBUILTIN;
682		cmdentry.u.index = BLTINCMD;
683		cmdentry.special = 1;
684	} else {
685		static const char PATH[] = "PATH=";
686		int cmd_flags = 0, bltinonly = 0;
687
688		/*
689		 * Modify the command lookup path, if a PATH= assignment
690		 * is present
691		 */
692		for (sp = varlist.list ; sp ; sp = sp->next)
693			if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
694				path = sp->text + sizeof(PATH) - 1;
695				/*
696				 * On `PATH=... command`, we need to make
697				 * sure that the command isn't using the
698				 * non-updated hash table of the outer PATH
699				 * setting and we need to make sure that
700				 * the hash table isn't filled with items
701				 * from the temporary setting.
702				 *
703				 * It would be better to forbit using and
704				 * updating the table while this command
705				 * runs, by the command finding mechanism
706				 * is heavily integrated with hash handling,
707				 * so we just delete the hash before and after
708				 * the command runs. Partly deleting like
709				 * changepatch() does doesn't seem worth the
710				 * bookinging effort, since most such runs add
711				 * directories in front of the new PATH.
712				 */
713				clearcmdentry(0);
714				do_clearcmdentry = 1;
715			}
716
717		for (;;) {
718			if (bltinonly) {
719				cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
720				if (cmdentry.u.index < 0) {
721					cmdentry.u.index = BLTINCMD;
722					argv--;
723					argc++;
724					break;
725				}
726			} else
727				find_command(argv[0], &cmdentry, cmd_flags, path);
728			/* implement the bltin and command builtins here */
729			if (cmdentry.cmdtype != CMDBUILTIN)
730				break;
731			if (cmdentry.u.index == BLTINCMD) {
732				if (argc == 1)
733					break;
734				argv++;
735				argc--;
736				bltinonly = 1;
737			} else if (cmdentry.u.index == COMMANDCMD) {
738				if (argc == 1)
739					break;
740				if (!strcmp(argv[1], "-p")) {
741					if (argc == 2)
742						break;
743					if (argv[2][0] == '-') {
744						if (strcmp(argv[2], "--"))
745							break;
746						if (argc == 3)
747							break;
748						argv += 3;
749						argc -= 3;
750					} else {
751						argv += 2;
752						argc -= 2;
753					}
754					path = _PATH_STDPATH;
755					clearcmdentry(0);
756					do_clearcmdentry = 1;
757				} else if (!strcmp(argv[1], "--")) {
758					if (argc == 2)
759						break;
760					argv += 2;
761					argc -= 2;
762				} else if (argv[1][0] == '-')
763					break;
764				else {
765					argv++;
766					argc--;
767				}
768				cmd_flags |= DO_NOFUNC;
769				bltinonly = 0;
770			} else
771				break;
772		}
773		/*
774		 * Special builtins lose their special properties when
775		 * called via 'command'.
776		 */
777		if (cmd_flags & DO_NOFUNC)
778			cmdentry.special = 0;
779	}
780
781	/* Fork off a child process if necessary. */
782	if (cmd->ncmd.backgnd
783	 || ((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
784	    && ((flags & EV_EXIT) == 0 || have_traps()))
785	 || ((flags & EV_BACKCMD) != 0
786	    && (cmdentry.cmdtype != CMDBUILTIN
787		 || cmdentry.u.index == CDCMD
788		 || cmdentry.u.index == DOTCMD
789		 || cmdentry.u.index == EVALCMD))) {
790		jp = makejob(cmd, 1);
791		mode = cmd->ncmd.backgnd;
792		if (flags & EV_BACKCMD) {
793			mode = FORK_NOJOB;
794			if (pipe(pip) < 0)
795				error("Pipe call failed: %s", strerror(errno));
796		}
797		if (forkshell(jp, cmd, mode) != 0)
798			goto parent;	/* at end of routine */
799		if (flags & EV_BACKCMD) {
800			FORCEINTON;
801			close(pip[0]);
802			if (pip[1] != 1) {
803				dup2(pip[1], 1);
804				close(pip[1]);
805			}
806		}
807		flags |= EV_EXIT;
808	}
809
810	/* This is the child process if a fork occurred. */
811	/* Execute the command. */
812	if (cmdentry.cmdtype == CMDFUNCTION) {
813#ifdef DEBUG
814		trputs("Shell function:  ");  trargs(argv);
815#endif
816		saveparam = shellparam;
817		shellparam.malloc = 0;
818		shellparam.reset = 1;
819		shellparam.nparam = argc - 1;
820		shellparam.p = argv + 1;
821		shellparam.optnext = NULL;
822		INTOFF;
823		savelocalvars = localvars;
824		localvars = NULL;
825		reffunc(cmdentry.u.func);
826		savehandler = handler;
827		if (setjmp(jmploc.loc)) {
828			if (exception == EXSHELLPROC)
829				freeparam(&saveparam);
830			else {
831				freeparam(&shellparam);
832				shellparam = saveparam;
833				if (exception == EXERROR || exception == EXEXEC)
834					popredir();
835			}
836			unreffunc(cmdentry.u.func);
837			poplocalvars();
838			localvars = savelocalvars;
839			funcnest--;
840			handler = savehandler;
841			longjmp(handler->loc, 1);
842		}
843		handler = &jmploc;
844		funcnest++;
845		redirect(cmd->ncmd.redirect, REDIR_PUSH);
846		INTON;
847		for (sp = varlist.list ; sp ; sp = sp->next)
848			mklocal(sp->text);
849		exitstatus = oexitstatus;
850		if (flags & EV_TESTED)
851			evaltree(getfuncnode(cmdentry.u.func), EV_TESTED);
852		else
853			evaltree(getfuncnode(cmdentry.u.func), 0);
854		INTOFF;
855		unreffunc(cmdentry.u.func);
856		poplocalvars();
857		localvars = savelocalvars;
858		freeparam(&shellparam);
859		shellparam = saveparam;
860		handler = savehandler;
861		funcnest--;
862		popredir();
863		INTON;
864		if (evalskip == SKIPFUNC) {
865			evalskip = 0;
866			skipcount = 0;
867		}
868		if (flags & EV_EXIT)
869			exitshell(exitstatus);
870	} else if (cmdentry.cmdtype == CMDBUILTIN) {
871#ifdef DEBUG
872		trputs("builtin command:  ");  trargs(argv);
873#endif
874		mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
875		if (flags == EV_BACKCMD) {
876			memout.nleft = 0;
877			memout.nextc = memout.buf;
878			memout.bufsize = 64;
879			mode |= REDIR_BACKQ;
880			cmdentry.special = 0;
881		}
882		savecmdname = commandname;
883		savetopfile = getcurrentfile();
884		cmdenviron = varlist.list;
885		e = -1;
886		savehandler = handler;
887		if (setjmp(jmploc.loc)) {
888			e = exception;
889			exitstatus = (e == EXINT)? SIGINT+128 : 2;
890			goto cmddone;
891		}
892		handler = &jmploc;
893		redirect(cmd->ncmd.redirect, mode);
894		if (cmdentry.special)
895			listsetvar(cmdenviron);
896		commandname = argv[0];
897		argptr = argv + 1;
898		nextopt_optptr = NULL;		/* initialize nextopt */
899		builtin_flags = flags;
900		exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
901		flushall();
902cmddone:
903		cmdenviron = NULL;
904		out1 = &output;
905		out2 = &errout;
906		freestdout();
907		if (e != EXSHELLPROC) {
908			commandname = savecmdname;
909			if (flags & EV_EXIT) {
910				exitshell(exitstatus);
911			}
912		}
913		handler = savehandler;
914		if (flags == EV_BACKCMD) {
915			backcmd->buf = memout.buf;
916			backcmd->nleft = memout.nextc - memout.buf;
917			memout.buf = NULL;
918		}
919		if (cmdentry.u.index != EXECCMD &&
920				(e == -1 || e == EXERROR || e == EXEXEC))
921			popredir();
922		if (e != -1) {
923			if ((e != EXERROR && e != EXEXEC)
924			    || cmdentry.special)
925				exraise(e);
926			popfilesupto(savetopfile);
927			if (flags != EV_BACKCMD)
928				FORCEINTON;
929		}
930	} else {
931#ifdef DEBUG
932		trputs("normal command:  ");  trargs(argv);
933#endif
934		redirect(cmd->ncmd.redirect, 0);
935		for (sp = varlist.list ; sp ; sp = sp->next)
936			setvareq(sp->text, VEXPORT|VSTACK);
937		envp = environment();
938		shellexec(argv, envp, path, cmdentry.u.index);
939		/*NOTREACHED*/
940	}
941	goto out;
942
943parent:	/* parent process gets here (if we forked) */
944	if (mode == 0) {	/* argument to fork */
945		INTOFF;
946		exitstatus = waitforjob(jp, &realstatus);
947		INTON;
948		if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
949			evalskip = SKIPBREAK;
950			skipcount = loopnest;
951		}
952	} else if (mode == 2) {
953		backcmd->fd = pip[0];
954		close(pip[1]);
955		backcmd->jp = jp;
956	}
957
958out:
959	if (lastarg)
960		setvar("_", lastarg, 0);
961	if (do_clearcmdentry)
962		clearcmdentry(0);
963	popstackmark(&smark);
964}
965
966
967
968/*
969 * Search for a command.  This is called before we fork so that the
970 * location of the command will be available in the parent as well as
971 * the child.  The check for "goodname" is an overly conservative
972 * check that the name will not be subject to expansion.
973 */
974
975STATIC void
976prehash(union node *n)
977{
978	struct cmdentry entry;
979
980	if (n && n->type == NCMD && n->ncmd.args)
981		if (goodname(n->ncmd.args->narg.text))
982			find_command(n->ncmd.args->narg.text, &entry, 0,
983				     pathval());
984}
985
986
987
988/*
989 * Builtin commands.  Builtin commands whose functions are closely
990 * tied to evaluation are implemented here.
991 */
992
993/*
994 * No command given, a bltin command with no arguments, or a bltin command
995 * with an invalid name.
996 */
997
998int
999bltincmd(int argc, char **argv)
1000{
1001	if (argc > 1) {
1002		out2fmt_flush("%s: not found\n", argv[1]);
1003		return 127;
1004	}
1005	/*
1006	 * Preserve exitstatus of a previous possible redirection
1007	 * as POSIX mandates
1008	 */
1009	return exitstatus;
1010}
1011
1012
1013/*
1014 * Handle break and continue commands.  Break, continue, and return are
1015 * all handled by setting the evalskip flag.  The evaluation routines
1016 * above all check this flag, and if it is set they start skipping
1017 * commands rather than executing them.  The variable skipcount is
1018 * the number of loops to break/continue, or the number of function
1019 * levels to return.  (The latter is always 1.)  It should probably
1020 * be an error to break out of more loops than exist, but it isn't
1021 * in the standard shell so we don't make it one here.
1022 */
1023
1024int
1025breakcmd(int argc, char **argv)
1026{
1027	int n = argc > 1 ? number(argv[1]) : 1;
1028
1029	if (n > loopnest)
1030		n = loopnest;
1031	if (n > 0) {
1032		evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
1033		skipcount = n;
1034	}
1035	return 0;
1036}
1037
1038/*
1039 * The `command' command.
1040 */
1041int
1042commandcmd(int argc, char **argv)
1043{
1044	static char stdpath[] = _PATH_STDPATH;
1045	char *path;
1046	int ch;
1047	int cmd = -1;
1048
1049	path = bltinlookup("PATH", 1);
1050
1051	optind = optreset = 1;
1052	opterr = 0;
1053	while ((ch = getopt(argc, argv, "pvV")) != -1) {
1054		switch (ch) {
1055		case 'p':
1056			path = stdpath;
1057			break;
1058		case 'v':
1059			cmd = TYPECMD_SMALLV;
1060			break;
1061		case 'V':
1062			cmd = TYPECMD_BIGV;
1063			break;
1064		case '?':
1065		default:
1066			error("unknown option: -%c", optopt);
1067		}
1068	}
1069	argc -= optind;
1070	argv += optind;
1071
1072	if (cmd != -1) {
1073		if (argc != 1)
1074			error("wrong number of arguments");
1075		return typecmd_impl(2, argv - 1, cmd, path);
1076	}
1077	if (argc != 0)
1078		error("commandcmd() called while it should not be");
1079
1080	/*
1081	 * Do nothing successfully if no command was specified;
1082	 * ksh also does this.
1083	 */
1084	return 0;
1085}
1086
1087
1088/*
1089 * The return command.
1090 */
1091
1092int
1093returncmd(int argc, char **argv)
1094{
1095	int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1096
1097	if (funcnest) {
1098		evalskip = SKIPFUNC;
1099		skipcount = 1;
1100	} else {
1101		/* skip the rest of the file */
1102		evalskip = SKIPFILE;
1103		skipcount = 1;
1104	}
1105	return ret;
1106}
1107
1108
1109int
1110falsecmd(int argc __unused, char **argv __unused)
1111{
1112	return 1;
1113}
1114
1115
1116int
1117truecmd(int argc __unused, char **argv __unused)
1118{
1119	return 0;
1120}
1121
1122
1123int
1124execcmd(int argc, char **argv)
1125{
1126	if (argc > 1) {
1127		struct strlist *sp;
1128
1129		iflag = 0;		/* exit on error */
1130		mflag = 0;
1131		optschanged();
1132		for (sp = cmdenviron; sp ; sp = sp->next)
1133			setvareq(sp->text, VEXPORT|VSTACK);
1134		shellexec(argv + 1, environment(), pathval(), 0);
1135
1136	}
1137	return 0;
1138}
1139
1140
1141int
1142timescmd(int argc __unused, char **argv __unused)
1143{
1144	struct rusage ru;
1145	long shumins, shsmins, chumins, chsmins;
1146	double shusecs, shssecs, chusecs, chssecs;
1147
1148	if (getrusage(RUSAGE_SELF, &ru) < 0)
1149		return 1;
1150	shumins = ru.ru_utime.tv_sec / 60;
1151	shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1152	shsmins = ru.ru_stime.tv_sec / 60;
1153	shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1154	if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1155		return 1;
1156	chumins = ru.ru_utime.tv_sec / 60;
1157	chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1158	chsmins = ru.ru_stime.tv_sec / 60;
1159	chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1160	out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1161	    shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1162	return 0;
1163}
1164