eval.c revision 199647 
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 199647 2009-11-22 14:04:20Z 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	struct parsefile *savetopfile;
597	volatile int e;
598	char *lastarg;
599	int realstatus;
600	int do_clearcmdentry;
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				outc(' ', &errout);
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				outc(' ', &errout);
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		outc('\n', &errout);
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		char *path = pathval();
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		find_command(argv[0], &cmdentry, 0, path);
718		/* implement the bltin builtin here */
719		if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) {
720			for (;;) {
721				argv++;
722				if (--argc == 0)
723					break;
724				if ((cmdentry.u.index = find_builtin(*argv,
725				    &cmdentry.special)) < 0) {
726					outfmt(&errout, "%s: not found\n", *argv);
727					exitstatus = 127;
728					flushout(&errout);
729					return;
730				}
731				if (cmdentry.u.index != BLTINCMD)
732					break;
733			}
734		}
735	}
736
737	/* Fork off a child process if necessary. */
738	if (cmd->ncmd.backgnd
739	 || ((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
740	    && ((flags & EV_EXIT) == 0 || have_traps()))
741	 || ((flags & EV_BACKCMD) != 0
742	    && (cmdentry.cmdtype != CMDBUILTIN
743		 || cmdentry.u.index == CDCMD
744		 || cmdentry.u.index == DOTCMD
745		 || cmdentry.u.index == EVALCMD))
746	 || (cmdentry.cmdtype == CMDBUILTIN &&
747	    cmdentry.u.index == COMMANDCMD)) {
748		jp = makejob(cmd, 1);
749		mode = cmd->ncmd.backgnd;
750		if (flags & EV_BACKCMD) {
751			mode = FORK_NOJOB;
752			if (pipe(pip) < 0)
753				error("Pipe call failed: %s", strerror(errno));
754		}
755		if (forkshell(jp, cmd, mode) != 0)
756			goto parent;	/* at end of routine */
757		if (flags & EV_BACKCMD) {
758			FORCEINTON;
759			close(pip[0]);
760			if (pip[1] != 1) {
761				dup2(pip[1], 1);
762				close(pip[1]);
763			}
764		}
765		flags |= EV_EXIT;
766	}
767
768	/* This is the child process if a fork occurred. */
769	/* Execute the command. */
770	if (cmdentry.cmdtype == CMDFUNCTION) {
771#ifdef DEBUG
772		trputs("Shell function:  ");  trargs(argv);
773#endif
774		redirect(cmd->ncmd.redirect, REDIR_PUSH);
775		saveparam = shellparam;
776		shellparam.malloc = 0;
777		shellparam.reset = 1;
778		shellparam.nparam = argc - 1;
779		shellparam.p = argv + 1;
780		shellparam.optnext = NULL;
781		INTOFF;
782		savelocalvars = localvars;
783		localvars = NULL;
784		reffunc(cmdentry.u.func);
785		INTON;
786		savehandler = handler;
787		if (setjmp(jmploc.loc)) {
788			if (exception == EXSHELLPROC)
789				freeparam(&saveparam);
790			else {
791				freeparam(&shellparam);
792				shellparam = saveparam;
793			}
794			unreffunc(cmdentry.u.func);
795			poplocalvars();
796			localvars = savelocalvars;
797			handler = savehandler;
798			longjmp(handler->loc, 1);
799		}
800		handler = &jmploc;
801		for (sp = varlist.list ; sp ; sp = sp->next)
802			mklocal(sp->text);
803		funcnest++;
804		exitstatus = oexitstatus;
805		if (flags & EV_TESTED)
806			evaltree(getfuncnode(cmdentry.u.func), EV_TESTED);
807		else
808			evaltree(getfuncnode(cmdentry.u.func), 0);
809		funcnest--;
810		INTOFF;
811		unreffunc(cmdentry.u.func);
812		poplocalvars();
813		localvars = savelocalvars;
814		freeparam(&shellparam);
815		shellparam = saveparam;
816		handler = savehandler;
817		popredir();
818		INTON;
819		if (evalskip == SKIPFUNC) {
820			evalskip = 0;
821			skipcount = 0;
822		}
823		if (flags & EV_EXIT)
824			exitshell(exitstatus);
825	} else if (cmdentry.cmdtype == CMDBUILTIN) {
826#ifdef DEBUG
827		trputs("builtin command:  ");  trargs(argv);
828#endif
829		mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
830		if (flags == EV_BACKCMD) {
831			memout.nleft = 0;
832			memout.nextc = memout.buf;
833			memout.bufsize = 64;
834			mode |= REDIR_BACKQ;
835		}
836		savecmdname = commandname;
837		savetopfile = getcurrentfile();
838		cmdenviron = varlist.list;
839		e = -1;
840		savehandler = handler;
841		if (setjmp(jmploc.loc)) {
842			e = exception;
843			exitstatus = (e == EXINT)? SIGINT+128 : 2;
844			goto cmddone;
845		}
846		handler = &jmploc;
847		redirect(cmd->ncmd.redirect, mode);
848		if (cmdentry.special)
849			listsetvar(cmdenviron);
850		commandname = argv[0];
851		argptr = argv + 1;
852		optptr = NULL;			/* initialize nextopt */
853		builtin_flags = flags;
854		exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
855		flushall();
856cmddone:
857		cmdenviron = NULL;
858		out1 = &output;
859		out2 = &errout;
860		freestdout();
861		if (e != EXSHELLPROC) {
862			commandname = savecmdname;
863			if (flags & EV_EXIT) {
864				exitshell(exitstatus);
865			}
866		}
867		handler = savehandler;
868		if (e != -1) {
869			if ((e != EXERROR && e != EXEXEC)
870			    || cmdentry.special)
871				exraise(e);
872			popfilesupto(savetopfile);
873			FORCEINTON;
874		}
875		if (cmdentry.u.index != EXECCMD)
876			popredir();
877		if (flags == EV_BACKCMD) {
878			backcmd->buf = memout.buf;
879			backcmd->nleft = memout.nextc - memout.buf;
880			memout.buf = NULL;
881		}
882	} else {
883#ifdef DEBUG
884		trputs("normal command:  ");  trargs(argv);
885#endif
886		clearredir();
887		redirect(cmd->ncmd.redirect, 0);
888		for (sp = varlist.list ; sp ; sp = sp->next)
889			setvareq(sp->text, VEXPORT|VSTACK);
890		envp = environment();
891		shellexec(argv, envp, pathval(), cmdentry.u.index);
892		/*NOTREACHED*/
893	}
894	goto out;
895
896parent:	/* parent process gets here (if we forked) */
897	if (mode == 0) {	/* argument to fork */
898		INTOFF;
899		exitstatus = waitforjob(jp, &realstatus);
900		INTON;
901		if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
902			evalskip = SKIPBREAK;
903			skipcount = loopnest;
904		}
905	} else if (mode == 2) {
906		backcmd->fd = pip[0];
907		close(pip[1]);
908		backcmd->jp = jp;
909	}
910
911out:
912	if (lastarg)
913		setvar("_", lastarg, 0);
914	if (do_clearcmdentry)
915		clearcmdentry(0);
916	popstackmark(&smark);
917}
918
919
920
921/*
922 * Search for a command.  This is called before we fork so that the
923 * location of the command will be available in the parent as well as
924 * the child.  The check for "goodname" is an overly conservative
925 * check that the name will not be subject to expansion.
926 */
927
928STATIC void
929prehash(union node *n)
930{
931	struct cmdentry entry;
932
933	if (n && n->type == NCMD && n->ncmd.args)
934		if (goodname(n->ncmd.args->narg.text))
935			find_command(n->ncmd.args->narg.text, &entry, 0,
936				     pathval());
937}
938
939
940
941/*
942 * Builtin commands.  Builtin commands whose functions are closely
943 * tied to evaluation are implemented here.
944 */
945
946/*
947 * No command given, or a bltin command with no arguments.
948 */
949
950int
951bltincmd(int argc __unused, char **argv __unused)
952{
953	/*
954	 * Preserve exitstatus of a previous possible redirection
955	 * as POSIX mandates
956	 */
957	return exitstatus;
958}
959
960
961/*
962 * Handle break and continue commands.  Break, continue, and return are
963 * all handled by setting the evalskip flag.  The evaluation routines
964 * above all check this flag, and if it is set they start skipping
965 * commands rather than executing them.  The variable skipcount is
966 * the number of loops to break/continue, or the number of function
967 * levels to return.  (The latter is always 1.)  It should probably
968 * be an error to break out of more loops than exist, but it isn't
969 * in the standard shell so we don't make it one here.
970 */
971
972int
973breakcmd(int argc, char **argv)
974{
975	int n = argc > 1 ? number(argv[1]) : 1;
976
977	if (n > loopnest)
978		n = loopnest;
979	if (n > 0) {
980		evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
981		skipcount = n;
982	}
983	return 0;
984}
985
986/*
987 * The `command' command.
988 */
989int
990commandcmd(int argc, char **argv)
991{
992	static char stdpath[] = _PATH_STDPATH;
993	struct jmploc loc, *old;
994	struct strlist *sp;
995	char *path;
996	int ch;
997	int cmd = -1;
998
999	for (sp = cmdenviron; sp ; sp = sp->next)
1000		setvareq(sp->text, VEXPORT|VSTACK);
1001	path = pathval();
1002
1003	optind = optreset = 1;
1004	opterr = 0;
1005	while ((ch = getopt(argc, argv, "pvV")) != -1) {
1006		switch (ch) {
1007		case 'p':
1008			path = stdpath;
1009			break;
1010		case 'v':
1011			cmd = TYPECMD_SMALLV;
1012			break;
1013		case 'V':
1014			cmd = TYPECMD_BIGV;
1015			break;
1016		case '?':
1017		default:
1018			error("unknown option: -%c", optopt);
1019		}
1020	}
1021	argc -= optind;
1022	argv += optind;
1023
1024	if (cmd != -1) {
1025		if (argc != 1)
1026			error("wrong number of arguments");
1027		return typecmd_impl(2, argv - 1, cmd);
1028	}
1029	if (argc != 0) {
1030		old = handler;
1031		handler = &loc;
1032		if (setjmp(handler->loc) == 0)
1033			shellexec(argv, environment(), path, 0);
1034		handler = old;
1035		if (exception == EXEXEC)
1036			exit(exerrno);
1037		exraise(exception);
1038	}
1039
1040	/*
1041	 * Do nothing successfully if no command was specified;
1042	 * ksh also does this.
1043	 */
1044	exit(0);
1045}
1046
1047
1048/*
1049 * The return command.
1050 */
1051
1052int
1053returncmd(int argc, char **argv)
1054{
1055	int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1056
1057	if (funcnest) {
1058		evalskip = SKIPFUNC;
1059		skipcount = 1;
1060	} else {
1061		/* skip the rest of the file */
1062		evalskip = SKIPFILE;
1063		skipcount = 1;
1064	}
1065	return ret;
1066}
1067
1068
1069int
1070falsecmd(int argc __unused, char **argv __unused)
1071{
1072	return 1;
1073}
1074
1075
1076int
1077truecmd(int argc __unused, char **argv __unused)
1078{
1079	return 0;
1080}
1081
1082
1083int
1084execcmd(int argc, char **argv)
1085{
1086	if (argc > 1) {
1087		struct strlist *sp;
1088
1089		iflag = 0;		/* exit on error */
1090		mflag = 0;
1091		optschanged();
1092		for (sp = cmdenviron; sp ; sp = sp->next)
1093			setvareq(sp->text, VEXPORT|VSTACK);
1094		shellexec(argv + 1, environment(), pathval(), 0);
1095
1096	}
1097	return 0;
1098}
1099
1100
1101int
1102timescmd(int argc __unused, char **argv __unused)
1103{
1104	struct rusage ru;
1105	long shumins, shsmins, chumins, chsmins;
1106	double shusecs, shssecs, chusecs, chssecs;
1107
1108	if (getrusage(RUSAGE_SELF, &ru) < 0)
1109		return 1;
1110	shumins = ru.ru_utime.tv_sec / 60;
1111	shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1112	shsmins = ru.ru_stime.tv_sec / 60;
1113	shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1114	if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1115		return 1;
1116	chumins = ru.ru_utime.tv_sec / 60;
1117	chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1118	chsmins = ru.ru_stime.tv_sec / 60;
1119	chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1120	out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1121	    shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1122	return 0;
1123}
1124