1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kenneth Almquist.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <paths.h>
36#include <signal.h>
37#include <stdlib.h>
38#include <unistd.h>
39#include <sys/resource.h>
40#include <errno.h>
41
42/*
43 * Evaluate a command.
44 */
45
46#include "shell.h"
47#include "nodes.h"
48#include "syntax.h"
49#include "expand.h"
50#include "parser.h"
51#include "jobs.h"
52#include "eval.h"
53#include "builtins.h"
54#include "options.h"
55#include "exec.h"
56#include "redir.h"
57#include "input.h"
58#include "output.h"
59#include "trap.h"
60#include "var.h"
61#include "memalloc.h"
62#include "error.h"
63#include "show.h"
64#include "mystring.h"
65#ifndef NO_HISTORY
66#include "lineedit.h"
67#endif
68
69
70int evalskip; /* set if we are skipping commands */
71int skipcount; /* number of levels to skip */
72static int loopnest; /* current loop nesting level */
73int funcnest; /* depth of function calls */
74static int builtin_flags; /* evalcommand flags for builtins */
75
76
77char *commandname;
78struct arglist *cmdenviron;
79int exitstatus; /* exit status of last command */
80int oexitstatus; /* saved exit status */
81
82
83static void evalloop(union node *, int);
84static void evalfor(union node *, int);
85static union node *evalcase(union node *);
86static void evalsubshell(union node *, int);
87static void evalredir(union node *, int);
88static void exphere(union node *, struct arglist *);
89static void expredir(union node *);
90static void evalpipe(union node *);
91static int is_valid_fast_cmdsubst(union node *n);
92static void evalcommand(union node *, int, struct backcmd *);
93static void prehash(union node *);
94
95
96/*
97 * Called to reset things after an exception.
98 */
99
100void
101reseteval(void)
102{
103 evalskip = 0;
104 loopnest = 0;
105}
106
107
108/*
109 * The eval command.
110 */
111
112int
113evalcmd(int argc, char **argv)
114{
115 char *p;
116 char *concat;
117 char **ap;
118
119 if (argc > 1) {
120 p = argv[1];
121 if (argc > 2) {
122 STARTSTACKSTR(concat);
123 ap = argv + 2;
124 for (;;) {
125 STPUTS(p, concat);
126 if ((p = *ap++) == NULL)
127 break;
128 STPUTC(' ', concat);
129 }
130 STPUTC('\0', concat);
131 p = grabstackstr(concat);
132 }
133 evalstring(p, builtin_flags);
134 } else
135 exitstatus = 0;
136 return exitstatus;
137}
138
139
140/*
141 * Execute a command or commands contained in a string.
142 */
143
144void
145evalstring(const char *s, int flags)
146{
147 union node *n;
148 struct stackmark smark;
149 int flags_exit;
150 int any;
151
152 flags_exit = flags & EV_EXIT;
153 flags &= ~EV_EXIT;
154 any = 0;
155 setstackmark(&smark);
156 setinputstring(s);
157 while ((n = parsecmd(0)) != NEOF) {
158 if (n != NULL && !nflag) {
159 if (flags_exit && preadateof())
160 evaltree(n, flags | EV_EXIT);
161 else
162 evaltree(n, flags);
163 any = 1;
164 if (evalskip)
165 break;
166 }
167 popstackmark(&smark);
168 setstackmark(&smark);
169 }
170 popfile();
171 popstackmark(&smark);
172 if (!any)
173 exitstatus = 0;
174 if (flags_exit)
175 exraise(EXEXIT);
176}
177
178
179/*
180 * Evaluate a parse tree. The value is left in the global variable
181 * exitstatus.
182 */
183
184void
185evaltree(union node *n, int flags)
186{
187 int do_etest;
188 union node *next;
189 struct stackmark smark;
190
191 setstackmark(&smark);
192 do_etest = 0;
193 if (n == NULL) {
194 TRACE(("evaltree(NULL) called\n"));
195 exitstatus = 0;
196 goto out;
197 }
198 do {
199 next = NULL;
200#ifndef NO_HISTORY
201 displayhist = 1; /* show history substitutions done with fc */
202#endif
203 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
204 switch (n->type) {
205 case NSEMI:
206 evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
207 if (evalskip)
208 goto out;
209 next = n->nbinary.ch2;
210 break;
211 case NAND:
212 evaltree(n->nbinary.ch1, EV_TESTED);
213 if (evalskip || exitstatus != 0) {
214 goto out;
215 }
216 next = n->nbinary.ch2;
217 break;
218 case NOR:
219 evaltree(n->nbinary.ch1, EV_TESTED);
220 if (evalskip || exitstatus == 0)
221 goto out;
222 next = n->nbinary.ch2;
223 break;
224 case NREDIR:
225 evalredir(n, flags);
226 break;
227 case NSUBSHELL:
228 evalsubshell(n, flags);
229 do_etest = !(flags & EV_TESTED);
230 break;
231 case NBACKGND:
232 evalsubshell(n, flags);
233 break;
234 case NIF: {
235 evaltree(n->nif.test, EV_TESTED);
236 if (evalskip)
237 goto out;
238 if (exitstatus == 0)
239 next = n->nif.ifpart;
240 else if (n->nif.elsepart)
241 next = n->nif.elsepart;
242 else
243 exitstatus = 0;
244 break;
245 }
246 case NWHILE:
247 case NUNTIL:
248 evalloop(n, flags & ~EV_EXIT);
249 break;
250 case NFOR:
251 evalfor(n, flags & ~EV_EXIT);
252 break;
253 case NCASE:
254 next = evalcase(n);
255 break;
256 case NCLIST:
257 next = n->nclist.body;
258 break;
259 case NCLISTFALLTHRU:
260 if (n->nclist.body) {
261 evaltree(n->nclist.body, flags & ~EV_EXIT);
262 if (evalskip)
263 goto out;
264 }
265 next = n->nclist.next;
266 break;
267 case NDEFUN:
268 defun(n->narg.text, n->narg.next);
269 exitstatus = 0;
270 break;
271 case NNOT:
272 evaltree(n->nnot.com, EV_TESTED);
273 if (evalskip)
274 goto out;
275 exitstatus = !exitstatus;
276 break;
277
278 case NPIPE:
279 evalpipe(n);
280 do_etest = !(flags & EV_TESTED);
281 break;
282 case NCMD:
283 evalcommand(n, flags, (struct backcmd *)NULL);
284 do_etest = !(flags & EV_TESTED);
285 break;
286 default:
287 out1fmt("Node type = %d\n", n->type);
288 flushout(&output);
289 break;
290 }
291 n = next;
292 popstackmark(&smark);
293 setstackmark(&smark);
294 } while (n != NULL);
295out:
296 popstackmark(&smark);
297 if (pendingsig)
298 dotrap();
299 if (eflag && exitstatus != 0 && do_etest)
300 exitshell(exitstatus);
301 if (flags & EV_EXIT)
302 exraise(EXEXIT);
303}
304
305
306static void
307evalloop(union node *n, int flags)
308{
309 int status;
310
311 loopnest++;
312 status = 0;
313 for (;;) {
314 if (!evalskip)
315 evaltree(n->nbinary.ch1, EV_TESTED);
316 if (evalskip) {
317 if (evalskip == SKIPCONT && --skipcount <= 0) {
318 evalskip = 0;
319 continue;
320 }
321 if (evalskip == SKIPBREAK && --skipcount <= 0)
322 evalskip = 0;
323 if (evalskip == SKIPRETURN)
324 status = exitstatus;
325 break;
326 }
327 if (n->type == NWHILE) {
328 if (exitstatus != 0)
329 break;
330 } else {
331 if (exitstatus == 0)
332 break;
333 }
334 evaltree(n->nbinary.ch2, flags);
335 status = exitstatus;
336 }
337 loopnest--;
338 exitstatus = status;
339}
340
341
342
343static void
344evalfor(union node *n, int flags)
345{
346 struct arglist arglist;
347 union node *argp;
348 int i;
349 int status;
350
351 emptyarglist(&arglist);
352 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
353 oexitstatus = exitstatus;
354 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
355 }
356
357 loopnest++;
358 status = 0;
359 for (i = 0; i < arglist.count; i++) {
360 setvar(n->nfor.var, arglist.args[i], 0);
361 evaltree(n->nfor.body, flags);
362 status = exitstatus;
363 if (evalskip) {
364 if (evalskip == SKIPCONT && --skipcount <= 0) {
365 evalskip = 0;
366 continue;
367 }
368 if (evalskip == SKIPBREAK && --skipcount <= 0)
369 evalskip = 0;
370 break;
371 }
372 }
373 loopnest--;
374 exitstatus = status;
375}
376
377
378/*
379 * Evaluate a case statement, returning the selected tree.
380 *
381 * The exit status needs care to get right.
382 */
383
384static union node *
385evalcase(union node *n)
386{
387 union node *cp;
388 union node *patp;
389 struct arglist arglist;
390
391 emptyarglist(&arglist);
392 oexitstatus = exitstatus;
393 expandarg(n->ncase.expr, &arglist, EXP_TILDE);
394 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) {
395 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
396 if (casematch(patp, arglist.args[0])) {
397 while (cp->nclist.next &&
398 cp->type == NCLISTFALLTHRU &&
399 cp->nclist.body == NULL)
400 cp = cp->nclist.next;
401 if (cp->nclist.next &&
402 cp->type == NCLISTFALLTHRU)
403 return (cp);
404 if (cp->nclist.body == NULL)
405 exitstatus = 0;
406 return (cp->nclist.body);
407 }
408 }
409 }
410 exitstatus = 0;
411 return (NULL);
412}
413
414
415
416/*
417 * Kick off a subshell to evaluate a tree.
418 */
419
420static void
421evalsubshell(union node *n, int flags)
422{
423 struct job *jp;
424 int backgnd = (n->type == NBACKGND);
425
426 oexitstatus = exitstatus;
427 expredir(n->nredir.redirect);
428 if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
429 forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
430 if (backgnd)
431 flags &=~ EV_TESTED;
432 redirect(n->nredir.redirect, 0);
433 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
434 } else if (! backgnd) {
435 INTOFF;
436 exitstatus = waitforjob(jp, (int *)NULL);
437 INTON;
438 } else
439 exitstatus = 0;
440}
441
442
443/*
444 * Evaluate a redirected compound command.
445 */
446
447static void
448evalredir(union node *n, int flags)
449{
450 struct jmploc jmploc;
451 struct jmploc *savehandler;
452 volatile int in_redirect = 1;
453
454 oexitstatus = exitstatus;
455 expredir(n->nredir.redirect);
456 savehandler = handler;
457 if (setjmp(jmploc.loc)) {
458 int e;
459
460 handler = savehandler;
461 e = exception;
462 popredir();
463 if (e == EXERROR && in_redirect) {
464 FORCEINTON;
465 return;
466 }
467 longjmp(handler->loc, 1);
468 } else {
469 INTOFF;
470 handler = &jmploc;
471 redirect(n->nredir.redirect, REDIR_PUSH);
472 in_redirect = 0;
473 INTON;
474 evaltree(n->nredir.n, flags);
475 }
476 INTOFF;
477 handler = savehandler;
478 popredir();
479 INTON;
480}
481
482
483static void
484exphere(union node *redir, struct arglist *fn)
485{
486 struct jmploc jmploc;
487 struct jmploc *savehandler;
488 struct localvar *savelocalvars;
489 int need_longjmp = 0;
490 unsigned char saveoptreset;
491
492 redir->nhere.expdoc = "";
493 savelocalvars = localvars;
494 localvars = NULL;
495 saveoptreset = shellparam.reset;
496 forcelocal++;
497 savehandler = handler;
498 if (setjmp(jmploc.loc))
499 need_longjmp = exception != EXERROR;
500 else {
501 handler = &jmploc;
502 expandarg(redir->nhere.doc, fn, 0);
503 redir->nhere.expdoc = fn->args[0];
504 INTOFF;
505 }
506 handler = savehandler;
507 forcelocal--;
508 poplocalvars();
509 localvars = savelocalvars;
510 shellparam.reset = saveoptreset;
511 if (need_longjmp)
512 longjmp(handler->loc, 1);
513 INTON;
514}
515
516
517/*
518 * Compute the names of the files in a redirection list.
519 */
520
521static void
522expredir(union node *n)
523{
524 union node *redir;
525
526 for (redir = n ; redir ; redir = redir->nfile.next) {
527 struct arglist fn;
528 emptyarglist(&fn);
529 switch (redir->type) {
530 case NFROM:
531 case NTO:
532 case NFROMTO:
533 case NAPPEND:
534 case NCLOBBER:
535 expandarg(redir->nfile.fname, &fn, EXP_TILDE);
536 redir->nfile.expfname = fn.args[0];
537 break;
538 case NFROMFD:
539 case NTOFD:
540 if (redir->ndup.vname) {
541 expandarg(redir->ndup.vname, &fn, EXP_TILDE);
542 fixredir(redir, fn.args[0], 1);
543 }
544 break;
545 case NXHERE:
546 exphere(redir, &fn);
547 break;
548 }
549 }
550}
551
552
553
554/*
555 * Evaluate a pipeline. All the processes in the pipeline are children
556 * of the process creating the pipeline. (This differs from some versions
557 * of the shell, which make the last process in a pipeline the parent
558 * of all the rest.)
559 */
560
561static void
562evalpipe(union node *n)
563{
564 struct job *jp;
565 struct nodelist *lp;
566 int pipelen;
567 int prevfd;
568 int pip[2];
569
570 TRACE(("evalpipe(%p) called\n", (void *)n));
571 pipelen = 0;
572 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
573 pipelen++;
574 INTOFF;
575 jp = makejob(n, pipelen);
576 prevfd = -1;
577 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
578 prehash(lp->n);
579 pip[1] = -1;
580 if (lp->next) {
581 if (pipe(pip) < 0) {
582 if (prevfd >= 0)
583 close(prevfd);
584 error("Pipe call failed: %s", strerror(errno));
585 }
586 }
587 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
588 INTON;
589 if (prevfd > 0) {
590 dup2(prevfd, 0);
591 close(prevfd);
592 }
593 if (pip[1] >= 0) {
594 if (!(prevfd >= 0 && pip[0] == 0))
595 close(pip[0]);
596 if (pip[1] != 1) {
597 dup2(pip[1], 1);
598 close(pip[1]);
599 }
600 }
601 evaltree(lp->n, EV_EXIT);
602 }
603 if (prevfd >= 0)
604 close(prevfd);
605 prevfd = pip[0];
606 if (pip[1] != -1)
607 close(pip[1]);
608 }
609 INTON;
610 if (n->npipe.backgnd == 0) {
611 INTOFF;
612 exitstatus = waitforjob(jp, (int *)NULL);
613 TRACE(("evalpipe: job done exit status %d\n", exitstatus));
614 INTON;
615 } else
616 exitstatus = 0;
617}
618
619
620
621static int
622is_valid_fast_cmdsubst(union node *n)
623{
624
625 return (n->type == NCMD);
626}
627
628/*
629 * Execute a command inside back quotes. If it's a builtin command, we
630 * want to save its output in a block obtained from malloc. Otherwise
631 * we fork off a subprocess and get the output of the command via a pipe.
632 * Should be called with interrupts off.
633 */
634
635void
636evalbackcmd(union node *n, struct backcmd *result)
637{
638 int pip[2];
639 struct job *jp;
640 struct stackmark smark;
641 struct jmploc jmploc;
642 struct jmploc *savehandler;
643 struct localvar *savelocalvars;
644 unsigned char saveoptreset;
645
646 result->fd = -1;
647 result->buf = NULL;
648 result->nleft = 0;
649 result->jp = NULL;
650 if (n == NULL) {
651 exitstatus = 0;
652 return;
653 }
654 setstackmark(&smark);
655 exitstatus = oexitstatus;
656 if (is_valid_fast_cmdsubst(n)) {
657 savelocalvars = localvars;
658 localvars = NULL;
659 saveoptreset = shellparam.reset;
660 forcelocal++;
661 savehandler = handler;
662 if (setjmp(jmploc.loc)) {
663 if (exception == EXERROR)
664 /* nothing */;
665 else if (exception != 0) {
666 handler = savehandler;
667 forcelocal--;
668 poplocalvars();
669 localvars = savelocalvars;
670 shellparam.reset = saveoptreset;
671 longjmp(handler->loc, 1);
672 }
673 } else {
674 handler = &jmploc;
675 evalcommand(n, EV_BACKCMD, result);
676 }
677 handler = savehandler;
678 forcelocal--;
679 poplocalvars();
680 localvars = savelocalvars;
681 shellparam.reset = saveoptreset;
682 } else {
683 if (pipe(pip) < 0)
684 error("Pipe call failed: %s", strerror(errno));
685 jp = makejob(n, 1);
686 if (forkshell(jp, n, FORK_NOJOB) == 0) {
687 FORCEINTON;
688 close(pip[0]);
689 if (pip[1] != 1) {
690 dup2(pip[1], 1);
691 close(pip[1]);
692 }
693 evaltree(n, EV_EXIT);
694 }
695 close(pip[1]);
696 result->fd = pip[0];
697 result->jp = jp;
698 }
699 popstackmark(&smark);
700 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
701 result->fd, result->buf, result->nleft, result->jp));
702}
703
704static int
705mustexpandto(const char *argtext, const char *mask)
706{
707 for (;;) {
708 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) {
709 argtext++;
710 continue;
711 }
712 if (*argtext == CTLESC)
713 argtext++;
714 else if (BASESYNTAX[(int)*argtext] == CCTL)
715 return (0);
716 if (*argtext != *mask)
717 return (0);
718 if (*argtext == '\0')
719 return (1);
720 argtext++;
721 mask++;
722 }
723}
724
725static int
726isdeclarationcmd(struct narg *arg)
727{
728 int have_command = 0;
729
730 if (arg == NULL)
731 return (0);
732 while (mustexpandto(arg->text, "command")) {
733 have_command = 1;
734 arg = &arg->next->narg;
735 if (arg == NULL)
736 return (0);
737 /*
738 * To also allow "command -p" and "command --" as part of
739 * a declaration command, add code here.
740 * We do not do this, as ksh does not do it either and it
741 * is not required by POSIX.
742 */
743 }
744 return (mustexpandto(arg->text, "export") ||
745 mustexpandto(arg->text, "readonly") ||
746 (mustexpandto(arg->text, "local") &&
747 (have_command || !isfunc("local"))));
748}
749
750static void
751xtracecommand(struct arglist *varlist, int argc, char **argv)
752{
753 char sep = 0;
754 const char *text, *p, *ps4;
755 int i;
756
757 ps4 = expandstr(ps4val());
758 out2str(ps4 != NULL ? ps4 : ps4val());
759 for (i = 0; i < varlist->count; i++) {
760 text = varlist->args[i];
761 if (sep != 0)
762 out2c(' ');
763 p = strchr(text, '=');
764 if (p != NULL) {
765 p++;
766 outbin(text, p - text, out2);
767 out2qstr(p);
768 } else
769 out2qstr(text);
770 sep = ' ';
771 }
772 for (i = 0; i < argc; i++) {
773 text = argv[i];
774 if (sep != 0)
775 out2c(' ');
776 out2qstr(text);
777 sep = ' ';
778 }
779 out2c('\n');
780 flushout(&errout);
781}
782
783/*
784 * Check if a builtin can safely be executed in the same process,
785 * even though it should be in a subshell (command substitution).
786 * Note that jobid, jobs, times and trap can show information not
787 * available in a child process; this is deliberate.
788 * The arguments should already have been expanded.
789 */
790static int
791safe_builtin(int idx, int argc, char **argv)
792{
793 /* Generated from builtins.def. */
794 if (safe_builtin_always(idx))
795 return (1);
796 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD ||
797 idx == UMASKCMD)
798 return (argc <= 1 || (argc == 2 && argv[1][0] == '-'));
799 if (idx == SETCMD)
800 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' ||
801 argv[1][0] == '+') && argv[1][1] == 'o' &&
802 argv[1][2] == '\0'));
803 return (0);
804}
805
806/*
807 * Perform redirections, then execute a simple command with vfork.
808 * This cannot be used for command substitutions for two reasons:
809 * - Redirections might cause the error message for later redirections or for
810 * an unknown command to be sent to the pipe (to be substituted), and this
811 * might cause a deadlock if the message is too long.
812 * - The assignment of the pipe needs to come before instead of after the
813 * redirections.
814 */
815static int
816redirected_vforkexecshell(struct job *jp, union node *redir, char **argv,
817 char **envp, const char *path, int idx)
818{
819 struct jmploc jmploc;
820 struct jmploc *savehandler;
821 volatile int in_redirect = 1;
822
823 savehandler = handler;
824 if (setjmp(jmploc.loc)) {
825 int e;
826
827 handler = savehandler;
828 e = exception;
829 popredir();
830 if (e == EXERROR && in_redirect) {
831 FORCEINTON;
832 return 0;
833 }
834 longjmp(handler->loc, 1);
835 } else {
836 INTOFF;
837 handler = &jmploc;
838 redirect(redir, REDIR_PUSH);
839 in_redirect = 0;
840 INTON;
841 vforkexecshell(jp, argv, envp, path, idx, NULL);
842 }
843 INTOFF;
844 handler = savehandler;
845 popredir();
846 INTON;
847 return 1;
848}
849
850/*
851 * Execute a simple command.
852 * Note: This may or may not return if (flags & EV_EXIT).
853 */
854
855static void
856evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
857{
858 union node *argp;
859 struct arglist arglist;
860 struct arglist varlist;
861 char **argv;
862 int argc;
863 char **envp;
864 int varflag;
865 int mode;
866 int pip[2];
867 struct cmdentry cmdentry;
868 struct job *jp;
869 struct jmploc jmploc;
870 struct jmploc *savehandler;
871 char *savecmdname;
872 struct shparam saveparam;
873 struct localvar *savelocalvars;
874 struct parsefile *savetopfile;
875 volatile int e;
876 char *lastarg;
877 int signaled;
878 int do_clearcmdentry;
879 const char *path = pathval();
880 int i;
881
882 /* First expand the arguments. */
883 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
884 emptyarglist(&arglist);
885 emptyarglist(&varlist);
886 varflag = 1;
887 jp = NULL;
888 do_clearcmdentry = 0;
889 oexitstatus = exitstatus;
890 exitstatus = 0;
891 /* Add one slot at the beginning for tryexec(). */
892 appendarglist(&arglist, nullstr);
893 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
894 if (varflag && isassignment(argp->narg.text)) {
895 expandarg(argp, varflag == 1 ? &varlist : &arglist,
896 EXP_VARTILDE);
897 continue;
898 } else if (varflag == 1)
899 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
900 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
901 }
902 appendarglist(&arglist, nullstr);
903 expredir(cmd->ncmd.redirect);
904 argc = arglist.count - 2;
905 argv = &arglist.args[1];
906
907 argv[argc] = NULL;
908 lastarg = NULL;
909 if (iflag && funcnest == 0 && argc > 0)
910 lastarg = argv[argc - 1];
911
912 /* Print the command if xflag is set. */
913 if (xflag)
914 xtracecommand(&varlist, argc, argv);
915
916 /* Now locate the command. */
917 if (argc == 0) {
918 /* Variable assignment(s) without command */
919 cmdentry.cmdtype = CMDBUILTIN;
920 cmdentry.u.index = BLTINCMD;
921 cmdentry.special = 0;
922 } else {
923 static const char PATH[] = "PATH=";
924 int cmd_flags = 0, bltinonly = 0;
925
926 /*
927 * Modify the command lookup path, if a PATH= assignment
928 * is present
929 */
930 for (i = 0; i < varlist.count; i++)
931 if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) {
932 path = varlist.args[i] + sizeof(PATH) - 1;
933 /*
934 * On `PATH=... command`, we need to make
935 * sure that the command isn't using the
936 * non-updated hash table of the outer PATH
937 * setting and we need to make sure that
938 * the hash table isn't filled with items
939 * from the temporary setting.
940 *
941 * It would be better to forbid using and
942 * updating the table while this command
943 * runs, by the command finding mechanism
944 * is heavily integrated with hash handling,
945 * so we just delete the hash before and after
946 * the command runs. Partly deleting like
947 * changepatch() does doesn't seem worth the
948 * booking effort, since most such runs add
949 * directories in front of the new PATH.
950 */
951 clearcmdentry();
952 do_clearcmdentry = 1;
953 }
954
955 for (;;) {
956 if (bltinonly) {
957 cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
958 if (cmdentry.u.index < 0) {
959 cmdentry.u.index = BLTINCMD;
960 argv--;
961 argc++;
962 break;
963 }
964 } else
965 find_command(argv[0], &cmdentry, cmd_flags, path);
966 /* implement the bltin and command builtins here */
967 if (cmdentry.cmdtype != CMDBUILTIN)
968 break;
969 if (cmdentry.u.index == BLTINCMD) {
970 if (argc == 1)
971 break;
972 argv++;
973 argc--;
974 bltinonly = 1;
975 } else if (cmdentry.u.index == COMMANDCMD) {
976 if (argc == 1)
977 break;
978 if (!strcmp(argv[1], "-p")) {
979 if (argc == 2)
980 break;
981 if (argv[2][0] == '-') {
982 if (strcmp(argv[2], "--"))
983 break;
984 if (argc == 3)
985 break;
986 argv += 3;
987 argc -= 3;
988 } else {
989 argv += 2;
990 argc -= 2;
991 }
992 path = _PATH_STDPATH;
993 clearcmdentry();
994 do_clearcmdentry = 1;
995 } else if (!strcmp(argv[1], "--")) {
996 if (argc == 2)
997 break;
998 argv += 2;
999 argc -= 2;
1000 } else if (argv[1][0] == '-')
1001 break;
1002 else {
1003 argv++;
1004 argc--;
1005 }
1006 cmd_flags |= DO_NOFUNC;
1007 bltinonly = 0;
1008 } else
1009 break;
1010 }
1011 /*
1012 * Special builtins lose their special properties when
1013 * called via 'command'.
1014 */
1015 if (cmd_flags & DO_NOFUNC)
1016 cmdentry.special = 0;
1017 }
1018
1019 /* Fork off a child process if necessary. */
1020 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
1021 && ((flags & EV_EXIT) == 0 || have_traps()))
1022 || ((flags & EV_BACKCMD) != 0
1023 && (cmdentry.cmdtype != CMDBUILTIN ||
1024 !safe_builtin(cmdentry.u.index, argc, argv)))) {
1025 jp = makejob(cmd, 1);
1026 mode = FORK_FG;
1027 if (flags & EV_BACKCMD) {
1028 mode = FORK_NOJOB;
1029 if (pipe(pip) < 0)
1030 error("Pipe call failed: %s", strerror(errno));
1031 }
1032 if (cmdentry.cmdtype == CMDNORMAL &&
1033 (cmd->ncmd.redirect == NULL || (flags & EV_BACKCMD) == 0) &&
1034 varlist.count == 0 &&
1035 (mode == FORK_FG || mode == FORK_NOJOB) &&
1036 !disvforkset() && !iflag && !mflag) {
1037 if (cmd->ncmd.redirect != NULL) {
1038 if (redirected_vforkexecshell(jp,
1039 cmd->ncmd.redirect,
1040 argv, environment(), path,
1041 cmdentry.u.index))
1042 goto parent;
1043 else
1044 goto out;
1045 } else
1046 vforkexecshell(jp, argv, environment(), path,
1047 cmdentry.u.index,
1048 flags & EV_BACKCMD ? pip : NULL);
1049 goto parent;
1050 }
1051 if (forkshell(jp, cmd, mode) != 0)
1052 goto parent; /* at end of routine */
1053 if (flags & EV_BACKCMD) {
1054 FORCEINTON;
1055 close(pip[0]);
1056 if (pip[1] != 1) {
1057 dup2(pip[1], 1);
1058 close(pip[1]);
1059 }
1060 flags &= ~EV_BACKCMD;
1061 }
1062 flags |= EV_EXIT;
1063 }
1064
1065 /* This is the child process if a fork occurred. */
1066 /* Execute the command. */
1067 if (cmdentry.cmdtype == CMDFUNCTION) {
1068#ifdef DEBUG
1069 trputs("Shell function: "); trargs(argv);
1070#endif
1071 saveparam = shellparam;
1072 shellparam.malloc = 0;
1073 shellparam.reset = 1;
1074 shellparam.nparam = argc - 1;
1075 shellparam.p = argv + 1;
1076 shellparam.optp = NULL;
1077 shellparam.optnext = NULL;
1078 INTOFF;
1079 savelocalvars = localvars;
1080 localvars = NULL;
1081 reffunc(cmdentry.u.func);
1082 savehandler = handler;
1083 if (setjmp(jmploc.loc)) {
1084 popredir();
1085 unreffunc(cmdentry.u.func);
1086 poplocalvars();
1087 localvars = savelocalvars;
1088 freeparam(&shellparam);
1089 shellparam = saveparam;
1090 funcnest--;
1091 handler = savehandler;
1092 longjmp(handler->loc, 1);
1093 }
1094 handler = &jmploc;
1095 funcnest++;
1096 redirect(cmd->ncmd.redirect, REDIR_PUSH);
1097 INTON;
1098 for (i = 0; i < varlist.count; i++)
1099 mklocal(varlist.args[i]);
1100 exitstatus = oexitstatus;
1101 evaltree(getfuncnode(cmdentry.u.func),
1102 flags & (EV_TESTED | EV_EXIT));
1103 INTOFF;
1104 unreffunc(cmdentry.u.func);
1105 poplocalvars();
1106 localvars = savelocalvars;
1107 freeparam(&shellparam);
1108 shellparam = saveparam;
1109 handler = savehandler;
1110 funcnest--;
1111 popredir();
1112 INTON;
1113 if (evalskip == SKIPRETURN) {
1114 evalskip = 0;
1115 skipcount = 0;
1116 }
1117 if (jp)
1118 exitshell(exitstatus);
1119 } else if (cmdentry.cmdtype == CMDBUILTIN) {
1120#ifdef DEBUG
1121 trputs("builtin command: "); trargs(argv);
1122#endif
1123 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
1124 if (flags == EV_BACKCMD) {
1125 memout.nextc = memout.buf;
1126 mode |= REDIR_BACKQ;
1127 }
1128 savecmdname = commandname;
1129 savetopfile = getcurrentfile();
1130 cmdenviron = &varlist;
1131 e = -1;
1132 savehandler = handler;
1133 if (setjmp(jmploc.loc)) {
1134 e = exception;
1135 if (e == EXINT)
1136 exitstatus = SIGINT+128;
1137 goto cmddone;
1138 }
1139 handler = &jmploc;
1140 redirect(cmd->ncmd.redirect, mode);
1141 outclearerror(out1);
1142 /*
1143 * If there is no command word, redirection errors should
1144 * not be fatal but assignment errors should.
1145 */
1146 if (argc == 0)
1147 cmdentry.special = 1;
1148 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
1149 if (argc > 0)
1150 bltinsetlocale();
1151 commandname = argv[0];
1152 argptr = argv + 1;
1153 nextopt_optptr = NULL; /* initialize nextopt */
1154 builtin_flags = flags;
1155 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
1156 flushall();
1157 if (outiserror(out1)) {
1158 warning("write error on stdout");
1159 if (exitstatus == 0 || exitstatus == 1)
1160 exitstatus = 2;
1161 }
1162cmddone:
1163 if (argc > 0)
1164 bltinunsetlocale();
1165 cmdenviron = NULL;
1166 out1 = &output;
1167 out2 = &errout;
1168 freestdout();
1169 handler = savehandler;
1170 commandname = savecmdname;
1171 if (jp)
1172 exitshell(exitstatus);
1173 if (flags == EV_BACKCMD) {
1174 backcmd->buf = memout.buf;
1175 backcmd->nleft = memout.buf != NULL ?
1176 memout.nextc - memout.buf : 0;
1177 memout.buf = NULL;
1178 memout.nextc = NULL;
1179 memout.bufend = NULL;
1180 memout.bufsize = 64;
1181 }
1182 if (cmdentry.u.index != EXECCMD)
1183 popredir();
1184 if (e != -1) {
1185 if (e != EXERROR || cmdentry.special)
1186 exraise(e);
1187 popfilesupto(savetopfile);
1188 if (flags != EV_BACKCMD)
1189 FORCEINTON;
1190 }
1191 } else {
1192#ifdef DEBUG
1193 trputs("normal command: "); trargs(argv);
1194#endif
1195 redirect(cmd->ncmd.redirect, 0);
1196 for (i = 0; i < varlist.count; i++)
1197 setvareq(varlist.args[i], VEXPORT|VSTACK);
1198 envp = environment();
1199 shellexec(argv, envp, path, cmdentry.u.index);
1200 /*NOTREACHED*/
1201 }
1202 goto out;
1203
1204parent: /* parent process gets here (if we forked) */
1205 if (mode == FORK_FG) { /* argument to fork */
1206 INTOFF;
1207 exitstatus = waitforjob(jp, &signaled);
1208 INTON;
1209 if (iflag && loopnest > 0 && signaled) {
1210 evalskip = SKIPBREAK;
1211 skipcount = loopnest;
1212 }
1213 } else if (mode == FORK_NOJOB) {
1214 backcmd->fd = pip[0];
1215 close(pip[1]);
1216 backcmd->jp = jp;
1217 }
1218
1219out:
1220 if (lastarg)
1221 setvar("_", lastarg, 0);
1222 if (do_clearcmdentry)
1223 clearcmdentry();
1224}
1225
1226
1227
1228/*
1229 * Search for a command. This is called before we fork so that the
1230 * location of the command will be available in the parent as well as
1231 * the child. The check for "goodname" is an overly conservative
1232 * check that the name will not be subject to expansion.
1233 */
1234
1235static void
1236prehash(union node *n)
1237{
1238 struct cmdentry entry;
1239
1240 if (n && n->type == NCMD && n->ncmd.args)
1241 if (goodname(n->ncmd.args->narg.text))
1242 find_command(n->ncmd.args->narg.text, &entry, 0,
1243 pathval());
1244}
1245
1246
1247
1248/*
1249 * Builtin commands. Builtin commands whose functions are closely
1250 * tied to evaluation are implemented here.
1251 */
1252
1253/*
1254 * No command given, a bltin command with no arguments, or a bltin command
1255 * with an invalid name.
1256 */
1257
1258int
1259bltincmd(int argc, char **argv)
1260{
1261 if (argc > 1) {
1262 out2fmt_flush("%s: not found\n", argv[1]);
1263 return 127;
1264 }
1265 /*
1266 * Preserve exitstatus of a previous possible command substitution
1267 * as POSIX mandates
1268 */
1269 return exitstatus;
1270}
1271
1272
1273/*
1274 * Handle break and continue commands. Break, continue, and return are
1275 * all handled by setting the evalskip flag. The evaluation routines
1276 * above all check this flag, and if it is set they start skipping
1277 * commands rather than executing them. The variable skipcount is
1278 * the number of loops to break/continue, or the number of function
1279 * levels to return. (The latter is always 1.) It should probably
1280 * be an error to break out of more loops than exist, but it isn't
1281 * in the standard shell so we don't make it one here.
1282 */
1283
1284int
1285breakcmd(int argc, char **argv)
1286{
1287 long n;
1288 char *end;
1289
1290 if (argc > 1) {
1291 /* Allow arbitrarily large numbers. */
1292 n = strtol(argv[1], &end, 10);
1293 if (!is_digit(argv[1][0]) || *end != '\0')
1294 error("Illegal number: %s", argv[1]);
1295 } else
1296 n = 1;
1297 if (n > loopnest)
1298 n = loopnest;
1299 if (n > 0) {
1300 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
1301 skipcount = n;
1302 }
1303 return 0;
1304}
1305
1306/*
1307 * The `command' command.
1308 */
1309int
1310commandcmd(int argc __unused, char **argv __unused)
1311{
1312 const char *path;
1313 int ch;
1314 int cmd = -1;
1315
1316 path = bltinlookup("PATH", 1);
1317
1318 while ((ch = nextopt("pvV")) != '\0') {
1319 switch (ch) {
1320 case 'p':
1321 path = _PATH_STDPATH;
1322 break;
1323 case 'v':
1324 cmd = TYPECMD_SMALLV;
1325 break;
1326 case 'V':
1327 cmd = TYPECMD_BIGV;
1328 break;
1329 }
1330 }
1331
1332 if (cmd != -1) {
1333 if (*argptr == NULL || argptr[1] != NULL)
1334 error("wrong number of arguments");
1335 return typecmd_impl(2, argptr - 1, cmd, path);
1336 }
1337 if (*argptr != NULL)
1338 error("commandcmd bad call");
1339
1340 /*
1341 * Do nothing successfully if no command was specified;
1342 * ksh also does this.
1343 */
1344 return 0;
1345}
1346
1347
1348/*
1349 * The return command.
1350 */
1351
1352int
1353returncmd(int argc, char **argv)
1354{
1355 int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1356
1357 evalskip = SKIPRETURN;
1358 skipcount = 1;
1359 return ret;
1360}
1361
1362
1363int
1364falsecmd(int argc __unused, char **argv __unused)
1365{
1366 return 1;
1367}
1368
1369
1370int
1371truecmd(int argc __unused, char **argv __unused)
1372{
1373 return 0;
1374}
1375
1376
1377int
1378execcmd(int argc, char **argv)
1379{
1380 int i;
1381
1382 /*
1383 * Because we have historically not supported any options,
1384 * only treat "--" specially.
1385 */
1386 if (argc > 1 && strcmp(argv[1], "--") == 0)
1387 argc--, argv++;
1388 if (argc > 1) {
1389 iflag = 0; /* exit on error */
1390 mflag = 0;
1391 optschanged();
1392 for (i = 0; i < cmdenviron->count; i++)
1393 setvareq(cmdenviron->args[i], VEXPORT|VSTACK);
1394 shellexec(argv + 1, environment(), pathval(), 0);
1395
1396 }
1397 return 0;
1398}
1399
1400
1401int
1402timescmd(int argc __unused, char **argv __unused)
1403{
1404 struct rusage ru;
1405 long shumins, shsmins, chumins, chsmins;
1406 double shusecs, shssecs, chusecs, chssecs;
1407
1408 if (getrusage(RUSAGE_SELF, &ru) < 0)
1409 return 1;
1410 shumins = ru.ru_utime.tv_sec / 60;
1411 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1412 shsmins = ru.ru_stime.tv_sec / 60;
1413 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1414 if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1415 return 1;
1416 chumins = ru.ru_utime.tv_sec / 60;
1417 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1418 chsmins = ru.ru_stime.tv_sec / 60;
1419 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1420 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1421 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1422 return 0;
1423}
