eval.c revision 196634 
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 196634 2009-08-28 22:41:25Z 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
77MKINIT int 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	}
411	if (! backgnd) {
412		INTOFF;
413		exitstatus = waitforjob(jp, (int *)NULL);
414		INTON;
415	}
416}
417
418
419
420/*
421 * Compute the names of the files in a redirection list.
422 */
423
424STATIC void
425expredir(union node *n)
426{
427	union node *redir;
428
429	for (redir = n ; redir ; redir = redir->nfile.next) {
430		struct arglist fn;
431		fn.lastp = &fn.list;
432		oexitstatus = exitstatus;
433		switch (redir->type) {
434		case NFROM:
435		case NTO:
436		case NFROMTO:
437		case NAPPEND:
438		case NCLOBBER:
439			expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
440			redir->nfile.expfname = fn.list->text;
441			break;
442		case NFROMFD:
443		case NTOFD:
444			if (redir->ndup.vname) {
445				expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR);
446				fixredir(redir, fn.list->text, 1);
447			}
448			break;
449		}
450	}
451}
452
453
454
455/*
456 * Evaluate a pipeline.  All the processes in the pipeline are children
457 * of the process creating the pipeline.  (This differs from some versions
458 * of the shell, which make the last process in a pipeline the parent
459 * of all the rest.)
460 */
461
462STATIC void
463evalpipe(union node *n)
464{
465	struct job *jp;
466	struct nodelist *lp;
467	int pipelen;
468	int prevfd;
469	int pip[2];
470
471	TRACE(("evalpipe(%p) called\n", (void *)n));
472	pipelen = 0;
473	for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
474		pipelen++;
475	INTOFF;
476	jp = makejob(n, pipelen);
477	prevfd = -1;
478	for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
479		prehash(lp->n);
480		pip[1] = -1;
481		if (lp->next) {
482			if (pipe(pip) < 0) {
483				close(prevfd);
484				error("Pipe call failed: %s", strerror(errno));
485			}
486		}
487		if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
488			INTON;
489			if (prevfd > 0) {
490				dup2(prevfd, 0);
491				close(prevfd);
492			}
493			if (pip[1] >= 0) {
494				if (!(prevfd >= 0 && pip[0] == 0))
495					close(pip[0]);
496				if (pip[1] != 1) {
497					dup2(pip[1], 1);
498					close(pip[1]);
499				}
500			}
501			evaltree(lp->n, EV_EXIT);
502		}
503		if (prevfd >= 0)
504			close(prevfd);
505		prevfd = pip[0];
506		close(pip[1]);
507	}
508	INTON;
509	if (n->npipe.backgnd == 0) {
510		INTOFF;
511		exitstatus = waitforjob(jp, (int *)NULL);
512		TRACE(("evalpipe:  job done exit status %d\n", exitstatus));
513		INTON;
514	}
515}
516
517
518
519/*
520 * Execute a command inside back quotes.  If it's a builtin command, we
521 * want to save its output in a block obtained from malloc.  Otherwise
522 * we fork off a subprocess and get the output of the command via a pipe.
523 * Should be called with interrupts off.
524 */
525
526void
527evalbackcmd(union node *n, struct backcmd *result)
528{
529	int pip[2];
530	struct job *jp;
531	struct stackmark smark;		/* unnecessary */
532
533	setstackmark(&smark);
534	result->fd = -1;
535	result->buf = NULL;
536	result->nleft = 0;
537	result->jp = NULL;
538	if (n == NULL) {
539		exitstatus = 0;
540		goto out;
541	}
542	if (n->type == NCMD) {
543		exitstatus = oexitstatus;
544		evalcommand(n, EV_BACKCMD, result);
545	} else {
546		exitstatus = 0;
547		if (pipe(pip) < 0)
548			error("Pipe call failed: %s", strerror(errno));
549		jp = makejob(n, 1);
550		if (forkshell(jp, n, FORK_NOJOB) == 0) {
551			FORCEINTON;
552			close(pip[0]);
553			if (pip[1] != 1) {
554				dup2(pip[1], 1);
555				close(pip[1]);
556			}
557			evaltree(n, EV_EXIT);
558		}
559		close(pip[1]);
560		result->fd = pip[0];
561		result->jp = jp;
562	}
563out:
564	popstackmark(&smark);
565	TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
566		result->fd, result->buf, result->nleft, result->jp));
567}
568
569
570
571/*
572 * Execute a simple command.
573 */
574
575STATIC void
576evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
577{
578	struct stackmark smark;
579	union node *argp;
580	struct arglist arglist;
581	struct arglist varlist;
582	char **argv;
583	int argc;
584	char **envp;
585	int varflag;
586	struct strlist *sp;
587	int mode;
588	int pip[2];
589	struct cmdentry cmdentry;
590	struct job *jp;
591	struct jmploc jmploc;
592	struct jmploc *savehandler;
593	char *savecmdname;
594	struct shparam saveparam;
595	struct localvar *savelocalvars;
596	volatile int e;
597	char *lastarg;
598	int realstatus;
599	int do_clearcmdentry;
600
601	/* First expand the arguments. */
602	TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
603	setstackmark(&smark);
604	arglist.lastp = &arglist.list;
605	varlist.lastp = &varlist.list;
606	varflag = 1;
607	do_clearcmdentry = 0;
608	oexitstatus = exitstatus;
609	exitstatus = 0;
610	for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
611		char *p = argp->narg.text;
612		if (varflag && is_name(*p)) {
613			do {
614				p++;
615			} while (is_in_name(*p));
616			if (*p == '=') {
617				expandarg(argp, &varlist, EXP_VARTILDE);
618				continue;
619			}
620		}
621		expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
622		varflag = 0;
623	}
624	*arglist.lastp = NULL;
625	*varlist.lastp = NULL;
626	expredir(cmd->ncmd.redirect);
627	argc = 0;
628	for (sp = arglist.list ; sp ; sp = sp->next)
629		argc++;
630	argv = stalloc(sizeof (char *) * (argc + 1));
631
632	for (sp = arglist.list ; sp ; sp = sp->next) {
633		TRACE(("evalcommand arg: %s\n", sp->text));
634		*argv++ = sp->text;
635	}
636	*argv = NULL;
637	lastarg = NULL;
638	if (iflag && funcnest == 0 && argc > 0)
639		lastarg = argv[-1];
640	argv -= argc;
641
642	/* Print the command if xflag is set. */
643	if (xflag) {
644		char sep = 0;
645		const char *p;
646		out2str(ps4val());
647		for (sp = varlist.list ; sp ; sp = sp->next) {
648			if (sep != 0)
649				outc(' ', &errout);
650			p = sp->text;
651			while (*p != '=' && *p != '\0')
652				out2c(*p++);
653			if (*p != '\0') {
654				out2c(*p++);
655				out2qstr(p);
656			}
657			sep = ' ';
658		}
659		for (sp = arglist.list ; sp ; sp = sp->next) {
660			if (sep != 0)
661				outc(' ', &errout);
662			/* Disambiguate command looking like assignment. */
663			if (sp == arglist.list &&
664					strchr(sp->text, '=') != NULL &&
665					strchr(sp->text, '\'') == NULL) {
666				out2c('\'');
667				out2str(sp->text);
668				out2c('\'');
669			} else
670				out2qstr(sp->text);
671			sep = ' ';
672		}
673		outc('\n', &errout);
674		flushout(&errout);
675	}
676
677	/* Now locate the command. */
678	if (argc == 0) {
679		/* Variable assignment(s) without command */
680		cmdentry.cmdtype = CMDBUILTIN;
681		cmdentry.u.index = BLTINCMD;
682		cmdentry.special = 1;
683	} else {
684		static const char PATH[] = "PATH=";
685		char *path = pathval();
686
687		/*
688		 * Modify the command lookup path, if a PATH= assignment
689		 * is present
690		 */
691		for (sp = varlist.list ; sp ; sp = sp->next)
692			if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
693				path = sp->text + sizeof(PATH) - 1;
694				/*
695				 * On `PATH=... command`, we need to make
696				 * sure that the command isn't using the
697				 * non-updated hash table of the outer PATH
698				 * setting and we need to make sure that
699				 * the hash table isn't filled with items
700				 * from the temporary setting.
701				 *
702				 * It would be better to forbit using and
703				 * updating the table while this command
704				 * runs, by the command finding mechanism
705				 * is heavily integrated with hash handling,
706				 * so we just delete the hash before and after
707				 * the command runs. Partly deleting like
708				 * changepatch() does doesn't seem worth the
709				 * bookinging effort, since most such runs add
710				 * directories in front of the new PATH.
711				 */
712				clearcmdentry(0);
713				do_clearcmdentry = 1;
714			}
715
716		find_command(argv[0], &cmdentry, 1, path);
717		if (cmdentry.cmdtype == CMDUNKNOWN) {	/* command not found */
718			exitstatus = 127;
719			flushout(&errout);
720			return;
721		}
722		/* implement the bltin builtin here */
723		if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) {
724			for (;;) {
725				argv++;
726				if (--argc == 0)
727					break;
728				if ((cmdentry.u.index = find_builtin(*argv,
729				    &cmdentry.special)) < 0) {
730					outfmt(&errout, "%s: not found\n", *argv);
731					exitstatus = 127;
732					flushout(&errout);
733					return;
734				}
735				if (cmdentry.u.index != BLTINCMD)
736					break;
737			}
738		}
739	}
740
741	/* Fork off a child process if necessary. */
742	if (cmd->ncmd.backgnd
743	 || (cmdentry.cmdtype == CMDNORMAL
744	    && ((flags & EV_EXIT) == 0 || have_traps()))
745	 || ((flags & EV_BACKCMD) != 0
746	    && (cmdentry.cmdtype != CMDBUILTIN
747		 || cmdentry.u.index == CDCMD
748		 || cmdentry.u.index == DOTCMD
749		 || cmdentry.u.index == EVALCMD))
750	 || (cmdentry.cmdtype == CMDBUILTIN &&
751	    cmdentry.u.index == COMMANDCMD)) {
752		jp = makejob(cmd, 1);
753		mode = cmd->ncmd.backgnd;
754		if (flags & EV_BACKCMD) {
755			mode = FORK_NOJOB;
756			if (pipe(pip) < 0)
757				error("Pipe call failed: %s", strerror(errno));
758		}
759		if (forkshell(jp, cmd, mode) != 0)
760			goto parent;	/* at end of routine */
761		if (flags & EV_BACKCMD) {
762			FORCEINTON;
763			close(pip[0]);
764			if (pip[1] != 1) {
765				dup2(pip[1], 1);
766				close(pip[1]);
767			}
768		}
769		flags |= EV_EXIT;
770	}
771
772	/* This is the child process if a fork occurred. */
773	/* Execute the command. */
774	if (cmdentry.cmdtype == CMDFUNCTION) {
775#ifdef DEBUG
776		trputs("Shell function:  ");  trargs(argv);
777#endif
778		redirect(cmd->ncmd.redirect, REDIR_PUSH);
779		saveparam = shellparam;
780		shellparam.malloc = 0;
781		shellparam.reset = 1;
782		shellparam.nparam = argc - 1;
783		shellparam.p = argv + 1;
784		shellparam.optnext = NULL;
785		INTOFF;
786		savelocalvars = localvars;
787		localvars = NULL;
788		reffunc(cmdentry.u.func);
789		INTON;
790		savehandler = handler;
791		if (setjmp(jmploc.loc)) {
792			if (exception == EXSHELLPROC)
793				freeparam(&saveparam);
794			else {
795				freeparam(&shellparam);
796				shellparam = saveparam;
797			}
798			unreffunc(cmdentry.u.func);
799			poplocalvars();
800			localvars = savelocalvars;
801			handler = savehandler;
802			longjmp(handler->loc, 1);
803		}
804		handler = &jmploc;
805		for (sp = varlist.list ; sp ; sp = sp->next)
806			mklocal(sp->text);
807		funcnest++;
808		exitstatus = oexitstatus;
809		if (flags & EV_TESTED)
810			evaltree(getfuncnode(cmdentry.u.func), EV_TESTED);
811		else
812			evaltree(getfuncnode(cmdentry.u.func), 0);
813		funcnest--;
814		INTOFF;
815		unreffunc(cmdentry.u.func);
816		poplocalvars();
817		localvars = savelocalvars;
818		freeparam(&shellparam);
819		shellparam = saveparam;
820		handler = savehandler;
821		popredir();
822		INTON;
823		if (evalskip == SKIPFUNC) {
824			evalskip = 0;
825			skipcount = 0;
826		}
827		if (flags & EV_EXIT)
828			exitshell(exitstatus);
829	} else if (cmdentry.cmdtype == CMDBUILTIN) {
830#ifdef DEBUG
831		trputs("builtin command:  ");  trargs(argv);
832#endif
833		mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
834		if (flags == EV_BACKCMD) {
835			memout.nleft = 0;
836			memout.nextc = memout.buf;
837			memout.bufsize = 64;
838			mode |= REDIR_BACKQ;
839		}
840		savecmdname = commandname;
841		cmdenviron = varlist.list;
842		e = -1;
843		savehandler = handler;
844		if (setjmp(jmploc.loc)) {
845			e = exception;
846			exitstatus = (e == EXINT)? SIGINT+128 : 2;
847			goto cmddone;
848		}
849		handler = &jmploc;
850		redirect(cmd->ncmd.redirect, mode);
851		if (cmdentry.special)
852			listsetvar(cmdenviron);
853		commandname = argv[0];
854		argptr = argv + 1;
855		optptr = NULL;			/* initialize nextopt */
856		builtin_flags = flags;
857		exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
858		flushall();
859cmddone:
860		cmdenviron = NULL;
861		out1 = &output;
862		out2 = &errout;
863		freestdout();
864		if (e != EXSHELLPROC) {
865			commandname = savecmdname;
866			if (flags & EV_EXIT) {
867				exitshell(exitstatus);
868			}
869		}
870		handler = savehandler;
871		if (e != -1) {
872			if ((e != EXERROR && e != EXEXEC)
873			    || cmdentry.special)
874				exraise(e);
875			FORCEINTON;
876		}
877		if (cmdentry.u.index != EXECCMD)
878			popredir();
879		if (flags == EV_BACKCMD) {
880			backcmd->buf = memout.buf;
881			backcmd->nleft = memout.nextc - memout.buf;
882			memout.buf = NULL;
883		}
884	} else {
885#ifdef DEBUG
886		trputs("normal command:  ");  trargs(argv);
887#endif
888		clearredir();
889		redirect(cmd->ncmd.redirect, 0);
890		for (sp = varlist.list ; sp ; sp = sp->next)
891			setvareq(sp->text, VEXPORT|VSTACK);
892		envp = environment();
893		shellexec(argv, envp, pathval(), cmdentry.u.index);
894		/*NOTREACHED*/
895	}
896	goto out;
897
898parent:	/* parent process gets here (if we forked) */
899	if (mode == 0) {	/* argument to fork */
900		INTOFF;
901		exitstatus = waitforjob(jp, &realstatus);
902		INTON;
903		if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
904			evalskip = SKIPBREAK;
905			skipcount = loopnest;
906		}
907	} else if (mode == 2) {
908		backcmd->fd = pip[0];
909		close(pip[1]);
910		backcmd->jp = jp;
911	}
912
913out:
914	if (lastarg)
915		setvar("_", lastarg, 0);
916	if (do_clearcmdentry)
917		clearcmdentry(0);
918	popstackmark(&smark);
919}
920
921
922
923/*
924 * Search for a command.  This is called before we fork so that the
925 * location of the command will be available in the parent as well as
926 * the child.  The check for "goodname" is an overly conservative
927 * check that the name will not be subject to expansion.
928 */
929
930STATIC void
931prehash(union node *n)
932{
933	struct cmdentry entry;
934
935	if (n && n->type == NCMD && n->ncmd.args)
936		if (goodname(n->ncmd.args->narg.text))
937			find_command(n->ncmd.args->narg.text, &entry, 0,
938				     pathval());
939}
940
941
942
943/*
944 * Builtin commands.  Builtin commands whose functions are closely
945 * tied to evaluation are implemented here.
946 */
947
948/*
949 * No command given, or a bltin command with no arguments.
950 */
951
952int
953bltincmd(int argc __unused, char **argv __unused)
954{
955	/*
956	 * Preserve exitstatus of a previous possible redirection
957	 * as POSIX mandates
958	 */
959	return exitstatus;
960}
961
962
963/*
964 * Handle break and continue commands.  Break, continue, and return are
965 * all handled by setting the evalskip flag.  The evaluation routines
966 * above all check this flag, and if it is set they start skipping
967 * commands rather than executing them.  The variable skipcount is
968 * the number of loops to break/continue, or the number of function
969 * levels to return.  (The latter is always 1.)  It should probably
970 * be an error to break out of more loops than exist, but it isn't
971 * in the standard shell so we don't make it one here.
972 */
973
974int
975breakcmd(int argc, char **argv)
976{
977	int n = argc > 1 ? number(argv[1]) : 1;
978
979	if (n > loopnest)
980		n = loopnest;
981	if (n > 0) {
982		evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
983		skipcount = n;
984	}
985	return 0;
986}
987
988/*
989 * The `command' command.
990 */
991int
992commandcmd(int argc, char **argv)
993{
994	static char stdpath[] = _PATH_STDPATH;
995	struct jmploc loc, *old;
996	struct strlist *sp;
997	char *path;
998	int ch;
999	int cmd = -1;
1000
1001	for (sp = cmdenviron; sp ; sp = sp->next)
1002		setvareq(sp->text, VEXPORT|VSTACK);
1003	path = pathval();
1004
1005	optind = optreset = 1;
1006	opterr = 0;
1007	while ((ch = getopt(argc, argv, "pvV")) != -1) {
1008		switch (ch) {
1009		case 'p':
1010			path = stdpath;
1011			break;
1012		case 'v':
1013			cmd = TYPECMD_SMALLV;
1014			break;
1015		case 'V':
1016			cmd = TYPECMD_BIGV;
1017			break;
1018		case '?':
1019		default:
1020			error("unknown option: -%c", optopt);
1021		}
1022	}
1023	argc -= optind;
1024	argv += optind;
1025
1026	if (cmd != -1) {
1027		if (argc != 1)
1028			error("wrong number of arguments");
1029		return typecmd_impl(2, argv - 1, cmd);
1030	}
1031	if (argc != 0) {
1032		old = handler;
1033		handler = &loc;
1034		if (setjmp(handler->loc) == 0)
1035			shellexec(argv, environment(), path, 0);
1036		handler = old;
1037		if (exception == EXEXEC)
1038			exit(exerrno);
1039		exraise(exception);
1040	}
1041
1042	/*
1043	 * Do nothing successfully if no command was specified;
1044	 * ksh also does this.
1045	 */
1046	exit(0);
1047}
1048
1049
1050/*
1051 * The return command.
1052 */
1053
1054int
1055returncmd(int argc, char **argv)
1056{
1057	int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1058
1059	if (funcnest) {
1060		evalskip = SKIPFUNC;
1061		skipcount = 1;
1062	} else {
1063		/* skip the rest of the file */
1064		evalskip = SKIPFILE;
1065		skipcount = 1;
1066	}
1067	return ret;
1068}
1069
1070
1071int
1072falsecmd(int argc __unused, char **argv __unused)
1073{
1074	return 1;
1075}
1076
1077
1078int
1079truecmd(int argc __unused, char **argv __unused)
1080{
1081	return 0;
1082}
1083
1084
1085int
1086execcmd(int argc, char **argv)
1087{
1088	if (argc > 1) {
1089		struct strlist *sp;
1090
1091		iflag = 0;		/* exit on error */
1092		mflag = 0;
1093		optschanged();
1094		for (sp = cmdenviron; sp ; sp = sp->next)
1095			setvareq(sp->text, VEXPORT|VSTACK);
1096		shellexec(argv + 1, environment(), pathval(), 0);
1097
1098	}
1099	return 0;
1100}
1101
1102
1103int
1104timescmd(int argc __unused, char **argv __unused)
1105{
1106	struct rusage ru;
1107	long shumins, shsmins, chumins, chsmins;
1108	double shusecs, shssecs, chusecs, chssecs;
1109
1110	if (getrusage(RUSAGE_SELF, &ru) < 0)
1111		return 1;
1112	shumins = ru.ru_utime.tv_sec / 60;
1113	shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1114	shsmins = ru.ru_stime.tv_sec / 60;
1115	shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1116	if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1117		return 1;
1118	chumins = ru.ru_utime.tv_sec / 60;
1119	chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1120	chsmins = ru.ru_stime.tv_sec / 60;
1121	chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1122	out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1123	    shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1124	return 0;
1125}
1126