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 268927 2014-07-20 20:29:09Z 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 */
78int skipcount; /* number of levels to skip */
79static 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 union node *evalcase(union node *);
93static void evalsubshell(union node *, int);
94static void evalredir(union node *, int);
95static void exphere(union node *, struct arglist *);
96static void expredir(union node *);
97static void evalpipe(union node *);
98static int is_valid_fast_cmdsubst(union node *n);
99static void evalcommand(union node *, int, struct backcmd *);
100static void prehash(union node *);
101
102
103/*
104 * Called to reset things after an exception.
105 */
106
107void
108reseteval(void)
109{
110 evalskip = 0;
111 loopnest = 0;
112}
113
114
115/*
116 * The eval command.
117 */
118
119int
120evalcmd(int argc, char **argv)
121{
122 char *p;
123 char *concat;
124 char **ap;
125
126 if (argc > 1) {
127 p = argv[1];
128 if (argc > 2) {
129 STARTSTACKSTR(concat);
130 ap = argv + 2;
131 for (;;) {
132 STPUTS(p, concat);
133 if ((p = *ap++) == NULL)
134 break;
135 STPUTC(' ', concat);
136 }
137 STPUTC('\0', concat);
138 p = grabstackstr(concat);
139 }
140 evalstring(p, builtin_flags);
141 } else
142 exitstatus = 0;
143 return exitstatus;
144}
145
146
147/*
148 * Execute a command or commands contained in a string.
149 */
150
151void
152evalstring(char *s, int flags)
153{
154 union node *n;
155 struct stackmark smark;
156 int flags_exit;
157 int any;
158
159 flags_exit = flags & EV_EXIT;
160 flags &= ~EV_EXIT;
161 any = 0;
162 setstackmark(&smark);
163 setinputstring(s, 1);
164 while ((n = parsecmd(0)) != NEOF) {
165 if (n != NULL && !nflag) {
166 if (flags_exit && preadateof())
167 evaltree(n, flags | EV_EXIT);
168 else
169 evaltree(n, flags);
170 any = 1;
171 }
172 popstackmark(&smark);
173 setstackmark(&smark);
174 }
175 popfile();
176 popstackmark(&smark);
177 if (!any)
178 exitstatus = 0;
179 if (flags_exit)
180 exraise(EXEXIT);
181}
182
183
184/*
185 * Evaluate a parse tree. The value is left in the global variable
186 * exitstatus.
187 */
188
189void
190evaltree(union node *n, int flags)
191{
192 int do_etest;
193 union node *next;
194 struct stackmark smark;
195
196 setstackmark(&smark);
197 do_etest = 0;
198 if (n == NULL) {
199 TRACE(("evaltree(NULL) called\n"));
200 exitstatus = 0;
201 goto out;
202 }
203 do {
204 next = NULL;
205#ifndef NO_HISTORY
206 displayhist = 1; /* show history substitutions done with fc */
207#endif
208 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
209 switch (n->type) {
210 case NSEMI:
211 evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
212 if (evalskip)
213 goto out;
214 next = n->nbinary.ch2;
215 break;
216 case NAND:
217 evaltree(n->nbinary.ch1, EV_TESTED);
218 if (evalskip || exitstatus != 0) {
219 goto out;
220 }
221 next = n->nbinary.ch2;
222 break;
223 case NOR:
224 evaltree(n->nbinary.ch1, EV_TESTED);
225 if (evalskip || exitstatus == 0)
226 goto out;
227 next = n->nbinary.ch2;
228 break;
229 case NREDIR:
230 evalredir(n, flags);
231 break;
232 case NSUBSHELL:
233 evalsubshell(n, flags);
234 do_etest = !(flags & EV_TESTED);
235 break;
236 case NBACKGND:
237 evalsubshell(n, flags);
238 break;
239 case NIF: {
240 evaltree(n->nif.test, EV_TESTED);
241 if (evalskip)
242 goto out;
243 if (exitstatus == 0)
244 next = n->nif.ifpart;
245 else if (n->nif.elsepart)
246 next = n->nif.elsepart;
247 else
248 exitstatus = 0;
249 break;
250 }
251 case NWHILE:
252 case NUNTIL:
253 evalloop(n, flags & ~EV_EXIT);
254 break;
255 case NFOR:
256 evalfor(n, flags & ~EV_EXIT);
257 break;
258 case NCASE:
259 next = evalcase(n);
260 break;
261 case NCLIST:
262 next = n->nclist.body;
263 break;
264 case NCLISTFALLTHRU:
265 if (n->nclist.body) {
266 evaltree(n->nclist.body, flags & ~EV_EXIT);
267 if (evalskip)
268 goto out;
269 }
270 next = n->nclist.next;
271 break;
272 case NDEFUN:
273 defun(n->narg.text, n->narg.next);
274 exitstatus = 0;
275 break;
276 case NNOT:
277 evaltree(n->nnot.com, EV_TESTED);
278 if (evalskip)
279 goto out;
280 exitstatus = !exitstatus;
281 break;
282
283 case NPIPE:
284 evalpipe(n);
285 do_etest = !(flags & EV_TESTED);
286 break;
287 case NCMD:
288 evalcommand(n, flags, (struct backcmd *)NULL);
289 do_etest = !(flags & EV_TESTED);
290 break;
291 default:
292 out1fmt("Node type = %d\n", n->type);
293 flushout(&output);
294 break;
295 }
296 n = next;
297 popstackmark(&smark);
298 setstackmark(&smark);
299 } while (n != NULL);
300out:
301 popstackmark(&smark);
302 if (pendingsig)
303 dotrap();
304 if (eflag && exitstatus != 0 && do_etest)
305 exitshell(exitstatus);
306 if (flags & EV_EXIT)
307 exraise(EXEXIT);
308}
309
310
311static void
312evalloop(union node *n, int flags)
313{
314 int status;
315
316 loopnest++;
317 status = 0;
318 for (;;) {
319 evaltree(n->nbinary.ch1, EV_TESTED);
320 if (evalskip) {
321skipping: if (evalskip == SKIPCONT && --skipcount <= 0) {
322 evalskip = 0;
323 continue;
324 }
325 if (evalskip == SKIPBREAK && --skipcount <= 0)
326 evalskip = 0;
327 if (evalskip == SKIPRETURN)
328 status = exitstatus;
329 break;
330 }
331 if (n->type == NWHILE) {
332 if (exitstatus != 0)
333 break;
334 } else {
335 if (exitstatus == 0)
336 break;
337 }
338 evaltree(n->nbinary.ch2, flags);
339 status = exitstatus;
340 if (evalskip)
341 goto skipping;
342 }
343 loopnest--;
344 exitstatus = status;
345}
346
347
348
349static void
350evalfor(union node *n, int flags)
351{
352 struct arglist arglist;
353 union node *argp;
354 struct strlist *sp;
355 int status;
356
357 arglist.lastp = &arglist.list;
358 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
359 oexitstatus = exitstatus;
360 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
361 }
362 *arglist.lastp = NULL;
363
364 loopnest++;
365 status = 0;
366 for (sp = arglist.list ; sp ; sp = sp->next) {
367 setvar(n->nfor.var, sp->text, 0);
368 evaltree(n->nfor.body, flags);
369 status = exitstatus;
370 if (evalskip) {
371 if (evalskip == SKIPCONT && --skipcount <= 0) {
372 evalskip = 0;
373 continue;
374 }
375 if (evalskip == SKIPBREAK && --skipcount <= 0)
376 evalskip = 0;
377 break;
378 }
379 }
380 loopnest--;
381 exitstatus = status;
382}
383
384
385/*
386 * Evaluate a case statement, returning the selected tree.
387 *
388 * The exit status needs care to get right.
389 */
390
391static union node *
392evalcase(union node *n)
393{
394 union node *cp;
395 union node *patp;
396 struct arglist arglist;
397
398 arglist.lastp = &arglist.list;
399 oexitstatus = exitstatus;
400 expandarg(n->ncase.expr, &arglist, EXP_TILDE);
401 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) {
402 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
403 if (casematch(patp, arglist.list->text)) {
404 while (cp->nclist.next &&
405 cp->type == NCLISTFALLTHRU &&
406 cp->nclist.body == NULL)
407 cp = cp->nclist.next;
408 if (cp->nclist.next &&
409 cp->type == NCLISTFALLTHRU)
410 return (cp);
411 if (cp->nclist.body == NULL)
412 exitstatus = 0;
413 return (cp->nclist.body);
414 }
415 }
416 }
417 exitstatus = 0;
418 return (NULL);
419}
420
421
422
423/*
424 * Kick off a subshell to evaluate a tree.
425 */
426
427static void
428evalsubshell(union node *n, int flags)
429{
430 struct job *jp;
431 int backgnd = (n->type == NBACKGND);
432
433 oexitstatus = exitstatus;
434 expredir(n->nredir.redirect);
435 if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
436 forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
437 if (backgnd)
438 flags &=~ EV_TESTED;
439 redirect(n->nredir.redirect, 0);
440 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
441 } else if (! backgnd) {
442 INTOFF;
443 exitstatus = waitforjob(jp, (int *)NULL);
444 INTON;
445 } else
446 exitstatus = 0;
447}
448
449
450/*
451 * Evaluate a redirected compound command.
452 */
453
454static void
455evalredir(union node *n, int flags)
456{
457 struct jmploc jmploc;
458 struct jmploc *savehandler;
459 volatile int in_redirect = 1;
460
461 oexitstatus = exitstatus;
462 expredir(n->nredir.redirect);
463 savehandler = handler;
464 if (setjmp(jmploc.loc)) {
465 int e;
466
467 handler = savehandler;
468 e = exception;
469 popredir();
470 if (e == EXERROR || e == EXEXEC) {
471 if (in_redirect) {
472 exitstatus = 2;
473 return;
474 }
475 }
476 longjmp(handler->loc, 1);
477 } else {
478 INTOFF;
479 handler = &jmploc;
480 redirect(n->nredir.redirect, REDIR_PUSH);
481 in_redirect = 0;
482 INTON;
483 evaltree(n->nredir.n, flags);
484 }
485 INTOFF;
486 handler = savehandler;
487 popredir();
488 INTON;
489}
490
491
492static void
493exphere(union node *redir, struct arglist *fn)
494{
495 struct jmploc jmploc;
496 struct jmploc *savehandler;
497 struct localvar *savelocalvars;
498 int need_longjmp = 0;
499
500 redir->nhere.expdoc = nullstr;
501 savelocalvars = localvars;
502 localvars = NULL;
503 forcelocal++;
504 savehandler = handler;
505 if (setjmp(jmploc.loc))
506 need_longjmp = exception != EXERROR && exception != EXEXEC;
507 else {
508 handler = &jmploc;
509 expandarg(redir->nhere.doc, fn, 0);
510 redir->nhere.expdoc = fn->list->text;
511 INTOFF;
512 }
513 handler = savehandler;
514 forcelocal--;
515 poplocalvars();
516 localvars = savelocalvars;
517 if (need_longjmp)
518 longjmp(handler->loc, 1);
519 INTON;
520}
521
522
523/*
524 * Compute the names of the files in a redirection list.
525 */
526
527static void
528expredir(union node *n)
529{
530 union node *redir;
531
532 for (redir = n ; redir ; redir = redir->nfile.next) {
533 struct arglist fn;
534 fn.lastp = &fn.list;
535 switch (redir->type) {
536 case NFROM:
537 case NTO:
538 case NFROMTO:
539 case NAPPEND:
540 case NCLOBBER:
541 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
542 redir->nfile.expfname = fn.list->text;
543 break;
544 case NFROMFD:
545 case NTOFD:
546 if (redir->ndup.vname) {
547 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR);
548 fixredir(redir, fn.list->text, 1);
549 }
550 break;
551 case NXHERE:
552 exphere(redir, &fn);
553 break;
554 }
555 }
556}
557
558
559
560/*
561 * Evaluate a pipeline. All the processes in the pipeline are children
562 * of the process creating the pipeline. (This differs from some versions
563 * of the shell, which make the last process in a pipeline the parent
564 * of all the rest.)
565 */
566
567static void
568evalpipe(union node *n)
569{
570 struct job *jp;
571 struct nodelist *lp;
572 int pipelen;
573 int prevfd;
574 int pip[2];
575
576 TRACE(("evalpipe(%p) called\n", (void *)n));
577 pipelen = 0;
578 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
579 pipelen++;
580 INTOFF;
581 jp = makejob(n, pipelen);
582 prevfd = -1;
583 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
584 prehash(lp->n);
585 pip[1] = -1;
586 if (lp->next) {
587 if (pipe(pip) < 0) {
588 if (prevfd >= 0)
589 close(prevfd);
590 error("Pipe call failed: %s", strerror(errno));
591 }
592 }
593 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
594 INTON;
595 if (prevfd > 0) {
596 dup2(prevfd, 0);
597 close(prevfd);
598 }
599 if (pip[1] >= 0) {
600 if (!(prevfd >= 0 && pip[0] == 0))
601 close(pip[0]);
602 if (pip[1] != 1) {
603 dup2(pip[1], 1);
604 close(pip[1]);
605 }
606 }
607 evaltree(lp->n, EV_EXIT);
608 }
609 if (prevfd >= 0)
610 close(prevfd);
611 prevfd = pip[0];
612 if (pip[1] != -1)
613 close(pip[1]);
614 }
615 INTON;
616 if (n->npipe.backgnd == 0) {
617 INTOFF;
618 exitstatus = waitforjob(jp, (int *)NULL);
619 TRACE(("evalpipe: job done exit status %d\n", exitstatus));
620 INTON;
621 } else
622 exitstatus = 0;
623}
624
625
626
627static int
628is_valid_fast_cmdsubst(union node *n)
629{
630
631 return (n->type == NCMD);
632}
633
634/*
635 * Execute a command inside back quotes. If it's a builtin command, we
636 * want to save its output in a block obtained from malloc. Otherwise
637 * we fork off a subprocess and get the output of the command via a pipe.
638 * Should be called with interrupts off.
639 */
640
641void
642evalbackcmd(union node *n, struct backcmd *result)
643{
644 int pip[2];
645 struct job *jp;
646 struct stackmark smark;
647 struct jmploc jmploc;
648 struct jmploc *savehandler;
649 struct localvar *savelocalvars;
650
651 setstackmark(&smark);
652 result->fd = -1;
653 result->buf = NULL;
654 result->nleft = 0;
655 result->jp = NULL;
656 if (n == NULL) {
657 exitstatus = 0;
658 goto out;
659 }
660 exitstatus = oexitstatus;
661 if (is_valid_fast_cmdsubst(n)) {
662 savelocalvars = localvars;
663 localvars = NULL;
664 forcelocal++;
665 savehandler = handler;
666 if (setjmp(jmploc.loc)) {
667 if (exception == EXERROR || exception == EXEXEC)
668 exitstatus = 2;
669 else if (exception != 0) {
670 handler = savehandler;
671 forcelocal--;
672 poplocalvars();
673 localvars = savelocalvars;
674 longjmp(handler->loc, 1);
675 }
676 } else {
677 handler = &jmploc;
678 evalcommand(n, EV_BACKCMD, result);
679 }
680 handler = savehandler;
681 forcelocal--;
682 poplocalvars();
683 localvars = savelocalvars;
684 } else {
685 if (pipe(pip) < 0)
686 error("Pipe call failed: %s", strerror(errno));
687 jp = makejob(n, 1);
688 if (forkshell(jp, n, FORK_NOJOB) == 0) {
689 FORCEINTON;
690 close(pip[0]);
691 if (pip[1] != 1) {
692 dup2(pip[1], 1);
693 close(pip[1]);
694 }
695 evaltree(n, EV_EXIT);
696 }
697 close(pip[1]);
698 result->fd = pip[0];
699 result->jp = jp;
700 }
701out:
702 popstackmark(&smark);
703 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
704 result->fd, result->buf, result->nleft, result->jp));
705}
706
707static int
708mustexpandto(const char *argtext, const char *mask)
709{
710 for (;;) {
711 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) {
712 argtext++;
713 continue;
714 }
715 if (*argtext == CTLESC)
716 argtext++;
717 else if (BASESYNTAX[(int)*argtext] == CCTL)
718 return (0);
719 if (*argtext != *mask)
720 return (0);
721 if (*argtext == '\0')
722 return (1);
723 argtext++;
724 mask++;
725 }
726}
727
728static int
729isdeclarationcmd(struct narg *arg)
730{
731 int have_command = 0;
732
733 if (arg == NULL)
734 return (0);
735 while (mustexpandto(arg->text, "command")) {
736 have_command = 1;
737 arg = &arg->next->narg;
738 if (arg == NULL)
739 return (0);
740 /*
741 * To also allow "command -p" and "command --" as part of
742 * a declaration command, add code here.
743 * We do not do this, as ksh does not do it either and it
744 * is not required by POSIX.
745 */
746 }
747 return (mustexpandto(arg->text, "export") ||
748 mustexpandto(arg->text, "readonly") ||
749 (mustexpandto(arg->text, "local") &&
750 (have_command || !isfunc("local"))));
751}
752
753static void
754xtracecommand(struct arglist *varlist, struct arglist *arglist)
755{
756 struct strlist *sp;
757 char sep = 0;
758 const char *p, *ps4;
759
760 ps4 = expandstr(ps4val());
761 out2str(ps4 != NULL ? ps4 : ps4val());
762 for (sp = varlist->list ; sp ; sp = sp->next) {
763 if (sep != 0)
764 out2c(' ');
765 p = strchr(sp->text, '=');
766 if (p != NULL) {
767 p++;
768 outbin(sp->text, p - sp->text, out2);
769 out2qstr(p);
770 } else
771 out2qstr(sp->text);
772 sep = ' ';
773 }
774 for (sp = arglist->list ; sp ; sp = sp->next) {
775 if (sep != 0)
776 out2c(' ');
777 /* Disambiguate command looking like assignment. */
778 if (sp == arglist->list &&
779 strchr(sp->text, '=') != NULL &&
780 strchr(sp->text, '\'') == NULL) {
781 out2c('\'');
782 out2str(sp->text);
783 out2c('\'');
784 } else
785 out2qstr(sp->text);
786 sep = ' ';
787 }
788 out2c('\n');
789 flushout(&errout);
790}
791
792/*
793 * Check if a builtin can safely be executed in the same process,
794 * even though it should be in a subshell (command substitution).
795 * Note that jobid, jobs, times and trap can show information not
796 * available in a child process; this is deliberate.
797 * The arguments should already have been expanded.
798 */
799static int
800safe_builtin(int idx, int argc, char **argv)
801{
802 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD ||
803 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD ||
804 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD ||
805 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD ||
806 idx == TYPECMD)
807 return (1);
808 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD ||
809 idx == UMASKCMD)
810 return (argc <= 1 || (argc == 2 && argv[1][0] == '-'));
811 if (idx == SETCMD)
812 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' ||
813 argv[1][0] == '+') && argv[1][1] == 'o' &&
814 argv[1][2] == '\0'));
815 return (0);
816}
817
818/*
819 * Execute a simple command.
820 * Note: This may or may not return if (flags & EV_EXIT).
821 */
822
823static void
824evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
825{
826 union node *argp;
827 struct arglist arglist;
828 struct arglist varlist;
829 char **argv;
830 int argc;
831 char **envp;
832 int varflag;
833 struct strlist *sp;
834 int mode;
835 int pip[2];
836 struct cmdentry cmdentry;
837 struct job *jp;
838 struct jmploc jmploc;
839 struct jmploc *savehandler;
840 char *savecmdname;
841 struct shparam saveparam;
842 struct localvar *savelocalvars;
843 struct parsefile *savetopfile;
844 volatile int e;
845 char *lastarg;
846 int realstatus;
847 int do_clearcmdentry;
848 const char *path = pathval();
849
850 /* First expand the arguments. */
851 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
852 arglist.lastp = &arglist.list;
853 varlist.lastp = &varlist.list;
854 varflag = 1;
855 jp = NULL;
856 do_clearcmdentry = 0;
857 oexitstatus = exitstatus;
858 exitstatus = 0;
859 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
860 if (varflag && isassignment(argp->narg.text)) {
861 expandarg(argp, varflag == 1 ? &varlist : &arglist,
862 EXP_VARTILDE);
863 continue;
864 } else if (varflag == 1)
865 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
866 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
867 }
868 *arglist.lastp = NULL;
869 *varlist.lastp = NULL;
870 expredir(cmd->ncmd.redirect);
871 argc = 0;
872 for (sp = arglist.list ; sp ; sp = sp->next)
873 argc++;
874 /* Add one slot at the beginning for tryexec(). */
875 argv = stalloc(sizeof (char *) * (argc + 2));
876 argv++;
877
878 for (sp = arglist.list ; sp ; sp = sp->next) {
879 TRACE(("evalcommand arg: %s\n", sp->text));
880 *argv++ = sp->text;
881 }
882 *argv = NULL;
883 lastarg = NULL;
884 if (iflag && funcnest == 0 && argc > 0)
885 lastarg = argv[-1];
886 argv -= argc;
887
888 /* Print the command if xflag is set. */
889 if (xflag)
890 xtracecommand(&varlist, &arglist);
891
892 /* Now locate the command. */
893 if (argc == 0) {
894 /* Variable assignment(s) without command */
895 cmdentry.cmdtype = CMDBUILTIN;
896 cmdentry.u.index = BLTINCMD;
897 cmdentry.special = 0;
898 } else {
899 static const char PATH[] = "PATH=";
900 int cmd_flags = 0, bltinonly = 0;
901
902 /*
903 * Modify the command lookup path, if a PATH= assignment
904 * is present
905 */
906 for (sp = varlist.list ; sp ; sp = sp->next)
907 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
908 path = sp->text + sizeof(PATH) - 1;
909 /*
910 * On `PATH=... command`, we need to make
911 * sure that the command isn't using the
912 * non-updated hash table of the outer PATH
913 * setting and we need to make sure that
914 * the hash table isn't filled with items
915 * from the temporary setting.
916 *
917 * It would be better to forbit using and
918 * updating the table while this command
919 * runs, by the command finding mechanism
920 * is heavily integrated with hash handling,
921 * so we just delete the hash before and after
922 * the command runs. Partly deleting like
923 * changepatch() does doesn't seem worth the
924 * bookinging effort, since most such runs add
925 * directories in front of the new PATH.
926 */
927 clearcmdentry();
928 do_clearcmdentry = 1;
929 }
930
931 for (;;) {
932 if (bltinonly) {
933 cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
934 if (cmdentry.u.index < 0) {
935 cmdentry.u.index = BLTINCMD;
936 argv--;
937 argc++;
938 break;
939 }
940 } else
941 find_command(argv[0], &cmdentry, cmd_flags, path);
942 /* implement the bltin and command builtins here */
943 if (cmdentry.cmdtype != CMDBUILTIN)
944 break;
945 if (cmdentry.u.index == BLTINCMD) {
946 if (argc == 1)
947 break;
948 argv++;
949 argc--;
950 bltinonly = 1;
951 } else if (cmdentry.u.index == COMMANDCMD) {
952 if (argc == 1)
953 break;
954 if (!strcmp(argv[1], "-p")) {
955 if (argc == 2)
956 break;
957 if (argv[2][0] == '-') {
958 if (strcmp(argv[2], "--"))
959 break;
960 if (argc == 3)
961 break;
962 argv += 3;
963 argc -= 3;
964 } else {
965 argv += 2;
966 argc -= 2;
967 }
968 path = _PATH_STDPATH;
969 clearcmdentry();
970 do_clearcmdentry = 1;
971 } else if (!strcmp(argv[1], "--")) {
972 if (argc == 2)
973 break;
974 argv += 2;
975 argc -= 2;
976 } else if (argv[1][0] == '-')
977 break;
978 else {
979 argv++;
980 argc--;
981 }
982 cmd_flags |= DO_NOFUNC;
983 bltinonly = 0;
984 } else
985 break;
986 }
987 /*
988 * Special builtins lose their special properties when
989 * called via 'command'.
990 */
991 if (cmd_flags & DO_NOFUNC)
992 cmdentry.special = 0;
993 }
994
995 /* Fork off a child process if necessary. */
996 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
997 && ((flags & EV_EXIT) == 0 || have_traps()))
998 || ((flags & EV_BACKCMD) != 0
999 && (cmdentry.cmdtype != CMDBUILTIN ||
1000 !safe_builtin(cmdentry.u.index, argc, argv)))) {
1001 jp = makejob(cmd, 1);
1002 mode = FORK_FG;
1003 if (flags & EV_BACKCMD) {
1004 mode = FORK_NOJOB;
1005 if (pipe(pip) < 0)
1006 error("Pipe call failed: %s", strerror(errno));
1007 }
1008 if (cmdentry.cmdtype == CMDNORMAL &&
1009 cmd->ncmd.redirect == NULL &&
1010 varlist.list == NULL &&
1011 (mode == FORK_FG || mode == FORK_NOJOB) &&
1012 !disvforkset() && !iflag && !mflag) {
1013 vforkexecshell(jp, argv, environment(), path,
1014 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL);
1015 goto parent;
1016 }
1017 if (forkshell(jp, cmd, mode) != 0)
1018 goto parent; /* at end of routine */
1019 if (flags & EV_BACKCMD) {
1020 FORCEINTON;
1021 close(pip[0]);
1022 if (pip[1] != 1) {
1023 dup2(pip[1], 1);
1024 close(pip[1]);
1025 }
1026 flags &= ~EV_BACKCMD;
1027 }
1028 flags |= EV_EXIT;
1029 }
1030
1031 /* This is the child process if a fork occurred. */
1032 /* Execute the command. */
1033 if (cmdentry.cmdtype == CMDFUNCTION) {
1034#ifdef DEBUG
1035 trputs("Shell function: "); trargs(argv);
1036#endif
1037 saveparam = shellparam;
1038 shellparam.malloc = 0;
1039 shellparam.reset = 1;
1040 shellparam.nparam = argc - 1;
1041 shellparam.p = argv + 1;
1042 shellparam.optnext = NULL;
1043 INTOFF;
1044 savelocalvars = localvars;
1045 localvars = NULL;
1046 reffunc(cmdentry.u.func);
1047 savehandler = handler;
1048 if (setjmp(jmploc.loc)) {
1049 freeparam(&shellparam);
1050 shellparam = saveparam;
1051 popredir();
1052 unreffunc(cmdentry.u.func);
1053 poplocalvars();
1054 localvars = savelocalvars;
1055 funcnest--;
1056 handler = savehandler;
1057 longjmp(handler->loc, 1);
1058 }
1059 handler = &jmploc;
1060 funcnest++;
1061 redirect(cmd->ncmd.redirect, REDIR_PUSH);
1062 INTON;
1063 for (sp = varlist.list ; sp ; sp = sp->next)
1064 mklocal(sp->text);
1065 exitstatus = oexitstatus;
1066 evaltree(getfuncnode(cmdentry.u.func),
1067 flags & (EV_TESTED | EV_EXIT));
1068 INTOFF;
1069 unreffunc(cmdentry.u.func);
1070 poplocalvars();
1071 localvars = savelocalvars;
1072 freeparam(&shellparam);
1073 shellparam = saveparam;
1074 handler = savehandler;
1075 funcnest--;
1076 popredir();
1077 INTON;
1078 if (evalskip == SKIPRETURN) {
1079 evalskip = 0;
1080 skipcount = 0;
1081 }
1082 if (jp)
1083 exitshell(exitstatus);
1084 } else if (cmdentry.cmdtype == CMDBUILTIN) {
1085#ifdef DEBUG
1086 trputs("builtin command: "); trargs(argv);
1087#endif
1088 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
1089 if (flags == EV_BACKCMD) {
1090 memout.nleft = 0;
1091 memout.nextc = memout.buf;
1092 memout.bufsize = 64;
1093 mode |= REDIR_BACKQ;
1094 }
1095 savecmdname = commandname;
1096 savetopfile = getcurrentfile();
1097 cmdenviron = varlist.list;
1098 e = -1;
1099 savehandler = handler;
1100 if (setjmp(jmploc.loc)) {
1101 e = exception;
1102 if (e == EXINT)
1103 exitstatus = SIGINT+128;
1104 else if (e != EXEXIT)
1105 exitstatus = 2;
1106 goto cmddone;
1107 }
1108 handler = &jmploc;
1109 redirect(cmd->ncmd.redirect, mode);
1110 outclearerror(out1);
1111 /*
1112 * If there is no command word, redirection errors should
1113 * not be fatal but assignment errors should.
1114 */
1115 if (argc == 0)
1116 cmdentry.special = 1;
1117 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
1118 if (argc > 0)
1119 bltinsetlocale();
1120 commandname = argv[0];
1121 argptr = argv + 1;
1122 nextopt_optptr = NULL; /* initialize nextopt */
1123 builtin_flags = flags;
1124 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
1125 flushall();
1126 if (outiserror(out1)) {
1127 warning("write error on stdout");
1128 if (exitstatus == 0 || exitstatus == 1)
1129 exitstatus = 2;
1130 }
1131cmddone:
1132 if (argc > 0)
1133 bltinunsetlocale();
1134 cmdenviron = NULL;
1135 out1 = &output;
1136 out2 = &errout;
1137 freestdout();
1138 handler = savehandler;
1139 commandname = savecmdname;
1140 if (jp)
1141 exitshell(exitstatus);
1142 if (flags == EV_BACKCMD) {
1143 backcmd->buf = memout.buf;
1144 backcmd->nleft = memout.nextc - memout.buf;
1145 memout.buf = NULL;
1146 }
1147 if (cmdentry.u.index != EXECCMD)
1148 popredir();
1149 if (e != -1) {
1150 if ((e != EXERROR && e != EXEXEC)
1151 || cmdentry.special)
1152 exraise(e);
1153 popfilesupto(savetopfile);
1154 if (flags != EV_BACKCMD)
1155 FORCEINTON;
1156 }
1157 } else {
1158#ifdef DEBUG
1159 trputs("normal command: "); trargs(argv);
1160#endif
1161 redirect(cmd->ncmd.redirect, 0);
1162 for (sp = varlist.list ; sp ; sp = sp->next)
1163 setvareq(sp->text, VEXPORT|VSTACK);
1164 envp = environment();
1165 shellexec(argv, envp, path, cmdentry.u.index);
1166 /*NOTREACHED*/
1167 }
1168 goto out;
1169
1170parent: /* parent process gets here (if we forked) */
1171 if (mode == FORK_FG) { /* argument to fork */
1172 INTOFF;
1173 exitstatus = waitforjob(jp, &realstatus);
1174 INTON;
1175 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
1176 evalskip = SKIPBREAK;
1177 skipcount = loopnest;
1178 }
1179 } else if (mode == FORK_NOJOB) {
1180 backcmd->fd = pip[0];
1181 close(pip[1]);
1182 backcmd->jp = jp;
1183 }
1184
1185out:
1186 if (lastarg)
1187 setvar("_", lastarg, 0);
1188 if (do_clearcmdentry)
1189 clearcmdentry();
1190}
1191
1192
1193
1194/*
1195 * Search for a command. This is called before we fork so that the
1196 * location of the command will be available in the parent as well as
1197 * the child. The check for "goodname" is an overly conservative
1198 * check that the name will not be subject to expansion.
1199 */
1200
1201static void
1202prehash(union node *n)
1203{
1204 struct cmdentry entry;
1205
1206 if (n && n->type == NCMD && n->ncmd.args)
1207 if (goodname(n->ncmd.args->narg.text))
1208 find_command(n->ncmd.args->narg.text, &entry, 0,
1209 pathval());
1210}
1211
1212
1213
1214/*
1215 * Builtin commands. Builtin commands whose functions are closely
1216 * tied to evaluation are implemented here.
1217 */
1218
1219/*
1220 * No command given, a bltin command with no arguments, or a bltin command
1221 * with an invalid name.
1222 */
1223
1224int
1225bltincmd(int argc, char **argv)
1226{
1227 if (argc > 1) {
1228 out2fmt_flush("%s: not found\n", argv[1]);
1229 return 127;
1230 }
1231 /*
1232 * Preserve exitstatus of a previous possible redirection
1233 * as POSIX mandates
1234 */
1235 return exitstatus;
1236}
1237
1238
1239/*
1240 * Handle break and continue commands. Break, continue, and return are
1241 * all handled by setting the evalskip flag. The evaluation routines
1242 * above all check this flag, and if it is set they start skipping
1243 * commands rather than executing them. The variable skipcount is
1244 * the number of loops to break/continue, or the number of function
1245 * levels to return. (The latter is always 1.) It should probably
1246 * be an error to break out of more loops than exist, but it isn't
1247 * in the standard shell so we don't make it one here.
1248 */
1249
1250int
1251breakcmd(int argc, char **argv)
1252{
1253 long n;
1254 char *end;
1255
1256 if (argc > 1) {
1257 /* Allow arbitrarily large numbers. */
1258 n = strtol(argv[1], &end, 10);
1259 if (!is_digit(argv[1][0]) || *end != '\0')
1260 error("Illegal number: %s", argv[1]);
1261 } else
1262 n = 1;
1263 if (n > loopnest)
1264 n = loopnest;
1265 if (n > 0) {
1266 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
1267 skipcount = n;
1268 }
1269 return 0;
1270}
1271
1272/*
1273 * The `command' command.
1274 */
1275int
1276commandcmd(int argc __unused, char **argv __unused)
1277{
1278 const char *path;
1279 int ch;
1280 int cmd = -1;
1281
1282 path = bltinlookup("PATH", 1);
1283
1284 while ((ch = nextopt("pvV")) != '\0') {
1285 switch (ch) {
1286 case 'p':
1287 path = _PATH_STDPATH;
1288 break;
1289 case 'v':
1290 cmd = TYPECMD_SMALLV;
1291 break;
1292 case 'V':
1293 cmd = TYPECMD_BIGV;
1294 break;
1295 }
1296 }
1297
1298 if (cmd != -1) {
1299 if (*argptr == NULL || argptr[1] != NULL)
1300 error("wrong number of arguments");
1301 return typecmd_impl(2, argptr - 1, cmd, path);
1302 }
1303 if (*argptr != NULL)
1304 error("commandcmd bad call");
1305
1306 /*
1307 * Do nothing successfully if no command was specified;
1308 * ksh also does this.
1309 */
1310 return 0;
1311}
1312
1313
1314/*
1315 * The return command.
1316 */
1317
1318int
1319returncmd(int argc, char **argv)
1320{
1321 int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1322
1323 evalskip = SKIPRETURN;
1324 skipcount = 1;
1325 return ret;
1326}
1327
1328
1329int
1330falsecmd(int argc __unused, char **argv __unused)
1331{
1332 return 1;
1333}
1334
1335
1336int
1337truecmd(int argc __unused, char **argv __unused)
1338{
1339 return 0;
1340}
1341
1342
1343int
1344execcmd(int argc, char **argv)
1345{
1346 /*
1347 * Because we have historically not supported any options,
1348 * only treat "--" specially.
1349 */
1350 if (argc > 1 && strcmp(argv[1], "--") == 0)
1351 argc--, argv++;
1352 if (argc > 1) {
1353 struct strlist *sp;
1354
1355 iflag = 0; /* exit on error */
1356 mflag = 0;
1357 optschanged();
1358 for (sp = cmdenviron; sp ; sp = sp->next)
1359 setvareq(sp->text, VEXPORT|VSTACK);
1360 shellexec(argv + 1, environment(), pathval(), 0);
1361
1362 }
1363 return 0;
1364}
1365
1366
1367int
1368timescmd(int argc __unused, char **argv __unused)
1369{
1370 struct rusage ru;
1371 long shumins, shsmins, chumins, chsmins;
1372 double shusecs, shssecs, chusecs, chssecs;
1373
1374 if (getrusage(RUSAGE_SELF, &ru) < 0)
1375 return 1;
1376 shumins = ru.ru_utime.tv_sec / 60;
1377 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1378 shsmins = ru.ru_stime.tv_sec / 60;
1379 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1380 if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1381 return 1;
1382 chumins = ru.ru_utime.tv_sec / 60;
1383 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1384 chsmins = ru.ru_stime.tv_sec / 60;
1385 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1386 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1387 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1388 return 0;
1389}