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 * 3. 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
35 static 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 340284 2018-11-09 14:58:24Z 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 <errno.h>
47
48 /*
49 * Evaluate a command.
50 */
51
52 #include "shell.h"
53 #include "nodes.h"
54 #include "syntax.h"
55 #include "expand.h"
56 #include "parser.h"
57 #include "jobs.h"
58 #include "eval.h"
59 #include "builtins.h"
60 #include "options.h"
61 #include "exec.h"
62 #include "redir.h"
63 #include "input.h"
64 #include "output.h"
65 #include "trap.h"
66 #include "var.h"
67 #include "memalloc.h"
68 #include "error.h"
69 #include "show.h"
70 #include "mystring.h"
71 #ifndef NO_HISTORY
72 #include "myhistedit.h"
73 #endif
74
75
76 int evalskip; /* set if we are skipping commands */
77 int skipcount; /* number of levels to skip */
78 static int loopnest; /* current loop nesting level */
79 int funcnest; /* depth of function calls */
80 static int builtin_flags; /* evalcommand flags for builtins */
81
82
83 char *commandname;
84 struct arglist *cmdenviron;
85 int exitstatus; /* exit status of last command */
86 int oexitstatus; /* saved exit status */
87
88
89 static void evalloop(union node *, int);
90 static void evalfor(union node *, int);
91 static union node *evalcase(union node *);
92 static void evalsubshell(union node *, int);
93 static void evalredir(union node *, int);
94 static void exphere(union node *, struct arglist *);
95 static void expredir(union node *);
96 static void evalpipe(union node *);
97 static int is_valid_fast_cmdsubst(union node *n);
98 static void evalcommand(union node *, int, struct backcmd *);
99 static void prehash(union node *);
100
101
102 /*
103 * Called to reset things after an exception.
104 */
105
106 void
reseteval(void)107 reseteval(void)
108 {
109 evalskip = 0;
110 loopnest = 0;
111 }
112
113
114 /*
115 * The eval command.
116 */
117
118 int
evalcmd(int argc,char ** argv)119 evalcmd(int argc, char **argv)
120 {
121 char *p;
122 char *concat;
123 char **ap;
124
125 if (argc > 1) {
126 p = argv[1];
127 if (argc > 2) {
128 STARTSTACKSTR(concat);
129 ap = argv + 2;
130 for (;;) {
131 STPUTS(p, concat);
132 if ((p = *ap++) == NULL)
133 break;
134 STPUTC(' ', concat);
135 }
136 STPUTC('\0', concat);
137 p = grabstackstr(concat);
138 }
139 evalstring(p, builtin_flags);
140 } else
141 exitstatus = 0;
142 return exitstatus;
143 }
144
145
146 /*
147 * Execute a command or commands contained in a string.
148 */
149
150 void
evalstring(const char * s,int flags)151 evalstring(const char *s, int flags)
152 {
153 union node *n;
154 struct stackmark smark;
155 int flags_exit;
156 int any;
157
158 flags_exit = flags & EV_EXIT;
159 flags &= ~EV_EXIT;
160 any = 0;
161 setstackmark(&smark);
162 setinputstring(s, 1);
163 while ((n = parsecmd(0)) != NEOF) {
164 if (n != NULL && !nflag) {
165 if (flags_exit && preadateof())
166 evaltree(n, flags | EV_EXIT);
167 else
168 evaltree(n, flags);
169 any = 1;
170 if (evalskip)
171 break;
172 }
173 popstackmark(&smark);
174 setstackmark(&smark);
175 }
176 popfile();
177 popstackmark(&smark);
178 if (!any)
179 exitstatus = 0;
180 if (flags_exit)
181 exraise(EXEXIT);
182 }
183
184
185 /*
186 * Evaluate a parse tree. The value is left in the global variable
187 * exitstatus.
188 */
189
190 void
evaltree(union node * n,int flags)191 evaltree(union node *n, int flags)
192 {
193 int do_etest;
194 union node *next;
195 struct stackmark smark;
196
197 setstackmark(&smark);
198 do_etest = 0;
199 if (n == NULL) {
200 TRACE(("evaltree(NULL) called\n"));
201 exitstatus = 0;
202 goto out;
203 }
204 do {
205 next = NULL;
206 #ifndef NO_HISTORY
207 displayhist = 1; /* show history substitutions done with fc */
208 #endif
209 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
210 switch (n->type) {
211 case NSEMI:
212 evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
213 if (evalskip)
214 goto out;
215 next = n->nbinary.ch2;
216 break;
217 case NAND:
218 evaltree(n->nbinary.ch1, EV_TESTED);
219 if (evalskip || exitstatus != 0) {
220 goto out;
221 }
222 next = n->nbinary.ch2;
223 break;
224 case NOR:
225 evaltree(n->nbinary.ch1, EV_TESTED);
226 if (evalskip || exitstatus == 0)
227 goto out;
228 next = n->nbinary.ch2;
229 break;
230 case NREDIR:
231 evalredir(n, flags);
232 break;
233 case NSUBSHELL:
234 evalsubshell(n, flags);
235 do_etest = !(flags & EV_TESTED);
236 break;
237 case NBACKGND:
238 evalsubshell(n, flags);
239 break;
240 case NIF: {
241 evaltree(n->nif.test, EV_TESTED);
242 if (evalskip)
243 goto out;
244 if (exitstatus == 0)
245 next = n->nif.ifpart;
246 else if (n->nif.elsepart)
247 next = n->nif.elsepart;
248 else
249 exitstatus = 0;
250 break;
251 }
252 case NWHILE:
253 case NUNTIL:
254 evalloop(n, flags & ~EV_EXIT);
255 break;
256 case NFOR:
257 evalfor(n, flags & ~EV_EXIT);
258 break;
259 case NCASE:
260 next = evalcase(n);
261 break;
262 case NCLIST:
263 next = n->nclist.body;
264 break;
265 case NCLISTFALLTHRU:
266 if (n->nclist.body) {
267 evaltree(n->nclist.body, flags & ~EV_EXIT);
268 if (evalskip)
269 goto out;
270 }
271 next = n->nclist.next;
272 break;
273 case NDEFUN:
274 defun(n->narg.text, n->narg.next);
275 exitstatus = 0;
276 break;
277 case NNOT:
278 evaltree(n->nnot.com, EV_TESTED);
279 if (evalskip)
280 goto out;
281 exitstatus = !exitstatus;
282 break;
283
284 case NPIPE:
285 evalpipe(n);
286 do_etest = !(flags & EV_TESTED);
287 break;
288 case NCMD:
289 evalcommand(n, flags, (struct backcmd *)NULL);
290 do_etest = !(flags & EV_TESTED);
291 break;
292 default:
293 out1fmt("Node type = %d\n", n->type);
294 flushout(&output);
295 break;
296 }
297 n = next;
298 popstackmark(&smark);
299 setstackmark(&smark);
300 } while (n != NULL);
301 out:
302 popstackmark(&smark);
303 if (pendingsig)
304 dotrap();
305 if (eflag && exitstatus != 0 && do_etest)
306 exitshell(exitstatus);
307 if (flags & EV_EXIT)
308 exraise(EXEXIT);
309 }
310
311
312 static void
evalloop(union node * n,int flags)313 evalloop(union node *n, int flags)
314 {
315 int status;
316
317 loopnest++;
318 status = 0;
319 for (;;) {
320 if (!evalskip)
321 evaltree(n->nbinary.ch1, EV_TESTED);
322 if (evalskip) {
323 if (evalskip == SKIPCONT && --skipcount <= 0) {
324 evalskip = 0;
325 continue;
326 }
327 if (evalskip == SKIPBREAK && --skipcount <= 0)
328 evalskip = 0;
329 if (evalskip == SKIPRETURN)
330 status = exitstatus;
331 break;
332 }
333 if (n->type == NWHILE) {
334 if (exitstatus != 0)
335 break;
336 } else {
337 if (exitstatus == 0)
338 break;
339 }
340 evaltree(n->nbinary.ch2, flags);
341 status = exitstatus;
342 }
343 loopnest--;
344 exitstatus = status;
345 }
346
347
348
349 static void
evalfor(union node * n,int flags)350 evalfor(union node *n, int flags)
351 {
352 struct arglist arglist;
353 union node *argp;
354 int i;
355 int status;
356
357 emptyarglist(&arglist);
358 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
359 oexitstatus = exitstatus;
360 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
361 }
362
363 loopnest++;
364 status = 0;
365 for (i = 0; i < arglist.count; i++) {
366 setvar(n->nfor.var, arglist.args[i], 0);
367 evaltree(n->nfor.body, flags);
368 status = exitstatus;
369 if (evalskip) {
370 if (evalskip == SKIPCONT && --skipcount <= 0) {
371 evalskip = 0;
372 continue;
373 }
374 if (evalskip == SKIPBREAK && --skipcount <= 0)
375 evalskip = 0;
376 break;
377 }
378 }
379 loopnest--;
380 exitstatus = status;
381 }
382
383
384 /*
385 * Evaluate a case statement, returning the selected tree.
386 *
387 * The exit status needs care to get right.
388 */
389
390 static union node *
evalcase(union node * n)391 evalcase(union node *n)
392 {
393 union node *cp;
394 union node *patp;
395 struct arglist arglist;
396
397 emptyarglist(&arglist);
398 oexitstatus = exitstatus;
399 expandarg(n->ncase.expr, &arglist, EXP_TILDE);
400 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) {
401 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
402 if (casematch(patp, arglist.args[0])) {
403 while (cp->nclist.next &&
404 cp->type == NCLISTFALLTHRU &&
405 cp->nclist.body == NULL)
406 cp = cp->nclist.next;
407 if (cp->nclist.next &&
408 cp->type == NCLISTFALLTHRU)
409 return (cp);
410 if (cp->nclist.body == NULL)
411 exitstatus = 0;
412 return (cp->nclist.body);
413 }
414 }
415 }
416 exitstatus = 0;
417 return (NULL);
418 }
419
420
421
422 /*
423 * Kick off a subshell to evaluate a tree.
424 */
425
426 static void
evalsubshell(union node * n,int flags)427 evalsubshell(union node *n, int flags)
428 {
429 struct job *jp;
430 int backgnd = (n->type == NBACKGND);
431
432 oexitstatus = exitstatus;
433 expredir(n->nredir.redirect);
434 if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
435 forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
436 if (backgnd)
437 flags &=~ EV_TESTED;
438 redirect(n->nredir.redirect, 0);
439 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
440 } else if (! backgnd) {
441 INTOFF;
442 exitstatus = waitforjob(jp, (int *)NULL);
443 INTON;
444 } else
445 exitstatus = 0;
446 }
447
448
449 /*
450 * Evaluate a redirected compound command.
451 */
452
453 static void
evalredir(union node * n,int flags)454 evalredir(union node *n, int flags)
455 {
456 struct jmploc jmploc;
457 struct jmploc *savehandler;
458 volatile int in_redirect = 1;
459
460 oexitstatus = exitstatus;
461 expredir(n->nredir.redirect);
462 savehandler = handler;
463 if (setjmp(jmploc.loc)) {
464 int e;
465
466 handler = savehandler;
467 e = exception;
468 popredir();
469 if (e == EXERROR && in_redirect) {
470 FORCEINTON;
471 return;
472 }
473 longjmp(handler->loc, 1);
474 } else {
475 INTOFF;
476 handler = &jmploc;
477 redirect(n->nredir.redirect, REDIR_PUSH);
478 in_redirect = 0;
479 INTON;
480 evaltree(n->nredir.n, flags);
481 }
482 INTOFF;
483 handler = savehandler;
484 popredir();
485 INTON;
486 }
487
488
489 static void
exphere(union node * redir,struct arglist * fn)490 exphere(union node *redir, struct arglist *fn)
491 {
492 struct jmploc jmploc;
493 struct jmploc *savehandler;
494 struct localvar *savelocalvars;
495 int need_longjmp = 0;
496 unsigned char saveoptreset;
497
498 redir->nhere.expdoc = "";
499 savelocalvars = localvars;
500 localvars = NULL;
501 saveoptreset = shellparam.reset;
502 forcelocal++;
503 savehandler = handler;
504 if (setjmp(jmploc.loc))
505 need_longjmp = exception != EXERROR;
506 else {
507 handler = &jmploc;
508 expandarg(redir->nhere.doc, fn, 0);
509 redir->nhere.expdoc = fn->args[0];
510 INTOFF;
511 }
512 handler = savehandler;
513 forcelocal--;
514 poplocalvars();
515 localvars = savelocalvars;
516 shellparam.reset = saveoptreset;
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
527 static void
expredir(union node * n)528 expredir(union node *n)
529 {
530 union node *redir;
531
532 for (redir = n ; redir ; redir = redir->nfile.next) {
533 struct arglist fn;
534 emptyarglist(&fn);
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);
542 redir->nfile.expfname = fn.args[0];
543 break;
544 case NFROMFD:
545 case NTOFD:
546 if (redir->ndup.vname) {
547 expandarg(redir->ndup.vname, &fn, EXP_TILDE);
548 fixredir(redir, fn.args[0], 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
567 static void
evalpipe(union node * n)568 evalpipe(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
627 static int
is_valid_fast_cmdsubst(union node * n)628 is_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
641 void
evalbackcmd(union node * n,struct backcmd * result)642 evalbackcmd(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 unsigned char saveoptreset;
651
652 result->fd = -1;
653 result->buf = NULL;
654 result->nleft = 0;
655 result->jp = NULL;
656 if (n == NULL) {
657 exitstatus = 0;
658 return;
659 }
660 setstackmark(&smark);
661 exitstatus = oexitstatus;
662 if (is_valid_fast_cmdsubst(n)) {
663 savelocalvars = localvars;
664 localvars = NULL;
665 saveoptreset = shellparam.reset;
666 forcelocal++;
667 savehandler = handler;
668 if (setjmp(jmploc.loc)) {
669 if (exception == EXERROR)
670 /* nothing */;
671 else if (exception != 0) {
672 handler = savehandler;
673 forcelocal--;
674 poplocalvars();
675 localvars = savelocalvars;
676 shellparam.reset = saveoptreset;
677 longjmp(handler->loc, 1);
678 }
679 } else {
680 handler = &jmploc;
681 evalcommand(n, EV_BACKCMD, result);
682 }
683 handler = savehandler;
684 forcelocal--;
685 poplocalvars();
686 localvars = savelocalvars;
687 shellparam.reset = saveoptreset;
688 } else {
689 if (pipe(pip) < 0)
690 error("Pipe call failed: %s", strerror(errno));
691 jp = makejob(n, 1);
692 if (forkshell(jp, n, FORK_NOJOB) == 0) {
693 FORCEINTON;
694 close(pip[0]);
695 if (pip[1] != 1) {
696 dup2(pip[1], 1);
697 close(pip[1]);
698 }
699 evaltree(n, EV_EXIT);
700 }
701 close(pip[1]);
702 result->fd = pip[0];
703 result->jp = jp;
704 }
705 popstackmark(&smark);
706 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
707 result->fd, result->buf, result->nleft, result->jp));
708 }
709
710 static int
mustexpandto(const char * argtext,const char * mask)711 mustexpandto(const char *argtext, const char *mask)
712 {
713 for (;;) {
714 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) {
715 argtext++;
716 continue;
717 }
718 if (*argtext == CTLESC)
719 argtext++;
720 else if (BASESYNTAX[(int)*argtext] == CCTL)
721 return (0);
722 if (*argtext != *mask)
723 return (0);
724 if (*argtext == '\0')
725 return (1);
726 argtext++;
727 mask++;
728 }
729 }
730
731 static int
isdeclarationcmd(struct narg * arg)732 isdeclarationcmd(struct narg *arg)
733 {
734 int have_command = 0;
735
736 if (arg == NULL)
737 return (0);
738 while (mustexpandto(arg->text, "command")) {
739 have_command = 1;
740 arg = &arg->next->narg;
741 if (arg == NULL)
742 return (0);
743 /*
744 * To also allow "command -p" and "command --" as part of
745 * a declaration command, add code here.
746 * We do not do this, as ksh does not do it either and it
747 * is not required by POSIX.
748 */
749 }
750 return (mustexpandto(arg->text, "export") ||
751 mustexpandto(arg->text, "readonly") ||
752 (mustexpandto(arg->text, "local") &&
753 (have_command || !isfunc("local"))));
754 }
755
756 static void
xtracecommand(struct arglist * varlist,int argc,char ** argv)757 xtracecommand(struct arglist *varlist, int argc, char **argv)
758 {
759 char sep = 0;
760 const char *text, *p, *ps4;
761 int i;
762
763 ps4 = expandstr(ps4val());
764 out2str(ps4 != NULL ? ps4 : ps4val());
765 for (i = 0; i < varlist->count; i++) {
766 text = varlist->args[i];
767 if (sep != 0)
768 out2c(' ');
769 p = strchr(text, '=');
770 if (p != NULL) {
771 p++;
772 outbin(text, p - text, out2);
773 out2qstr(p);
774 } else
775 out2qstr(text);
776 sep = ' ';
777 }
778 for (i = 0; i < argc; i++) {
779 text = argv[i];
780 if (sep != 0)
781 out2c(' ');
782 out2qstr(text);
783 sep = ' ';
784 }
785 out2c('\n');
786 flushout(&errout);
787 }
788
789 /*
790 * Check if a builtin can safely be executed in the same process,
791 * even though it should be in a subshell (command substitution).
792 * Note that jobid, jobs, times and trap can show information not
793 * available in a child process; this is deliberate.
794 * The arguments should already have been expanded.
795 */
796 static int
safe_builtin(int idx,int argc,char ** argv)797 safe_builtin(int idx, int argc, char **argv)
798 {
799 /* Generated from builtins.def. */
800 if (safe_builtin_always(idx))
801 return (1);
802 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD ||
803 idx == UMASKCMD)
804 return (argc <= 1 || (argc == 2 && argv[1][0] == '-'));
805 if (idx == SETCMD)
806 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' ||
807 argv[1][0] == '+') && argv[1][1] == 'o' &&
808 argv[1][2] == '\0'));
809 return (0);
810 }
811
812 /*
813 * Execute a simple command.
814 * Note: This may or may not return if (flags & EV_EXIT).
815 */
816
817 static void
evalcommand(union node * cmd,int flags,struct backcmd * backcmd)818 evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
819 {
820 union node *argp;
821 struct arglist arglist;
822 struct arglist varlist;
823 char **argv;
824 int argc;
825 char **envp;
826 int varflag;
827 int mode;
828 int pip[2];
829 struct cmdentry cmdentry;
830 struct job *jp;
831 struct jmploc jmploc;
832 struct jmploc *savehandler;
833 char *savecmdname;
834 struct shparam saveparam;
835 struct localvar *savelocalvars;
836 struct parsefile *savetopfile;
837 volatile int e;
838 char *lastarg;
839 int signaled;
840 int do_clearcmdentry;
841 const char *path = pathval();
842 int i;
843
844 /* First expand the arguments. */
845 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
846 emptyarglist(&arglist);
847 emptyarglist(&varlist);
848 varflag = 1;
849 jp = NULL;
850 do_clearcmdentry = 0;
851 oexitstatus = exitstatus;
852 exitstatus = 0;
853 /* Add one slot at the beginning for tryexec(). */
854 appendarglist(&arglist, nullstr);
855 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
856 if (varflag && isassignment(argp->narg.text)) {
857 expandarg(argp, varflag == 1 ? &varlist : &arglist,
858 EXP_VARTILDE);
859 continue;
860 } else if (varflag == 1)
861 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
862 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
863 }
864 appendarglist(&arglist, nullstr);
865 expredir(cmd->ncmd.redirect);
866 argc = arglist.count - 2;
867 argv = &arglist.args[1];
868
869 argv[argc] = NULL;
870 lastarg = NULL;
871 if (iflag && funcnest == 0 && argc > 0)
872 lastarg = argv[argc - 1];
873
874 /* Print the command if xflag is set. */
875 if (xflag)
876 xtracecommand(&varlist, argc, argv);
877
878 /* Now locate the command. */
879 if (argc == 0) {
880 /* Variable assignment(s) without command */
881 cmdentry.cmdtype = CMDBUILTIN;
882 cmdentry.u.index = BLTINCMD;
883 cmdentry.special = 0;
884 } else {
885 static const char PATH[] = "PATH=";
886 int cmd_flags = 0, bltinonly = 0;
887
888 /*
889 * Modify the command lookup path, if a PATH= assignment
890 * is present
891 */
892 for (i = 0; i < varlist.count; i++)
893 if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) {
894 path = varlist.args[i] + sizeof(PATH) - 1;
895 /*
896 * On `PATH=... command`, we need to make
897 * sure that the command isn't using the
898 * non-updated hash table of the outer PATH
899 * setting and we need to make sure that
900 * the hash table isn't filled with items
901 * from the temporary setting.
902 *
903 * It would be better to forbit using and
904 * updating the table while this command
905 * runs, by the command finding mechanism
906 * is heavily integrated with hash handling,
907 * so we just delete the hash before and after
908 * the command runs. Partly deleting like
909 * changepatch() does doesn't seem worth the
910 * bookinging effort, since most such runs add
911 * directories in front of the new PATH.
912 */
913 clearcmdentry();
914 do_clearcmdentry = 1;
915 }
916
917 for (;;) {
918 if (bltinonly) {
919 cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
920 if (cmdentry.u.index < 0) {
921 cmdentry.u.index = BLTINCMD;
922 argv--;
923 argc++;
924 break;
925 }
926 } else
927 find_command(argv[0], &cmdentry, cmd_flags, path);
928 /* implement the bltin and command builtins here */
929 if (cmdentry.cmdtype != CMDBUILTIN)
930 break;
931 if (cmdentry.u.index == BLTINCMD) {
932 if (argc == 1)
933 break;
934 argv++;
935 argc--;
936 bltinonly = 1;
937 } else if (cmdentry.u.index == COMMANDCMD) {
938 if (argc == 1)
939 break;
940 if (!strcmp(argv[1], "-p")) {
941 if (argc == 2)
942 break;
943 if (argv[2][0] == '-') {
944 if (strcmp(argv[2], "--"))
945 break;
946 if (argc == 3)
947 break;
948 argv += 3;
949 argc -= 3;
950 } else {
951 argv += 2;
952 argc -= 2;
953 }
954 path = _PATH_STDPATH;
955 clearcmdentry();
956 do_clearcmdentry = 1;
957 } else if (!strcmp(argv[1], "--")) {
958 if (argc == 2)
959 break;
960 argv += 2;
961 argc -= 2;
962 } else if (argv[1][0] == '-')
963 break;
964 else {
965 argv++;
966 argc--;
967 }
968 cmd_flags |= DO_NOFUNC;
969 bltinonly = 0;
970 } else
971 break;
972 }
973 /*
974 * Special builtins lose their special properties when
975 * called via 'command'.
976 */
977 if (cmd_flags & DO_NOFUNC)
978 cmdentry.special = 0;
979 }
980
981 /* Fork off a child process if necessary. */
982 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
983 && ((flags & EV_EXIT) == 0 || have_traps()))
984 || ((flags & EV_BACKCMD) != 0
985 && (cmdentry.cmdtype != CMDBUILTIN ||
986 !safe_builtin(cmdentry.u.index, argc, argv)))) {
987 jp = makejob(cmd, 1);
988 mode = FORK_FG;
989 if (flags & EV_BACKCMD) {
990 mode = FORK_NOJOB;
991 if (pipe(pip) < 0)
992 error("Pipe call failed: %s", strerror(errno));
993 }
994 if (cmdentry.cmdtype == CMDNORMAL &&
995 cmd->ncmd.redirect == NULL &&
996 varlist.count == 0 &&
997 (mode == FORK_FG || mode == FORK_NOJOB) &&
998 !disvforkset() && !iflag && !mflag) {
999 vforkexecshell(jp, argv, environment(), path,
1000 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL);
1001 goto parent;
1002 }
1003 if (forkshell(jp, cmd, mode) != 0)
1004 goto parent; /* at end of routine */
1005 if (flags & EV_BACKCMD) {
1006 FORCEINTON;
1007 close(pip[0]);
1008 if (pip[1] != 1) {
1009 dup2(pip[1], 1);
1010 close(pip[1]);
1011 }
1012 flags &= ~EV_BACKCMD;
1013 }
1014 flags |= EV_EXIT;
1015 }
1016
1017 /* This is the child process if a fork occurred. */
1018 /* Execute the command. */
1019 if (cmdentry.cmdtype == CMDFUNCTION) {
1020 #ifdef DEBUG
1021 trputs("Shell function: "); trargs(argv);
1022 #endif
1023 saveparam = shellparam;
1024 shellparam.malloc = 0;
1025 shellparam.reset = 1;
1026 shellparam.nparam = argc - 1;
1027 shellparam.p = argv + 1;
1028 shellparam.optp = NULL;
1029 shellparam.optnext = NULL;
1030 INTOFF;
1031 savelocalvars = localvars;
1032 localvars = NULL;
1033 reffunc(cmdentry.u.func);
1034 savehandler = handler;
1035 if (setjmp(jmploc.loc)) {
1036 popredir();
1037 unreffunc(cmdentry.u.func);
1038 poplocalvars();
1039 localvars = savelocalvars;
1040 freeparam(&shellparam);
1041 shellparam = saveparam;
1042 funcnest--;
1043 handler = savehandler;
1044 longjmp(handler->loc, 1);
1045 }
1046 handler = &jmploc;
1047 funcnest++;
1048 redirect(cmd->ncmd.redirect, REDIR_PUSH);
1049 INTON;
1050 for (i = 0; i < varlist.count; i++)
1051 mklocal(varlist.args[i]);
1052 exitstatus = oexitstatus;
1053 evaltree(getfuncnode(cmdentry.u.func),
1054 flags & (EV_TESTED | EV_EXIT));
1055 INTOFF;
1056 unreffunc(cmdentry.u.func);
1057 poplocalvars();
1058 localvars = savelocalvars;
1059 freeparam(&shellparam);
1060 shellparam = saveparam;
1061 handler = savehandler;
1062 funcnest--;
1063 popredir();
1064 INTON;
1065 if (evalskip == SKIPRETURN) {
1066 evalskip = 0;
1067 skipcount = 0;
1068 }
1069 if (jp)
1070 exitshell(exitstatus);
1071 } else if (cmdentry.cmdtype == CMDBUILTIN) {
1072 #ifdef DEBUG
1073 trputs("builtin command: "); trargs(argv);
1074 #endif
1075 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
1076 if (flags == EV_BACKCMD) {
1077 memout.nextc = memout.buf;
1078 mode |= REDIR_BACKQ;
1079 }
1080 savecmdname = commandname;
1081 savetopfile = getcurrentfile();
1082 cmdenviron = &varlist;
1083 e = -1;
1084 savehandler = handler;
1085 if (setjmp(jmploc.loc)) {
1086 e = exception;
1087 if (e == EXINT)
1088 exitstatus = SIGINT+128;
1089 goto cmddone;
1090 }
1091 handler = &jmploc;
1092 redirect(cmd->ncmd.redirect, mode);
1093 outclearerror(out1);
1094 /*
1095 * If there is no command word, redirection errors should
1096 * not be fatal but assignment errors should.
1097 */
1098 if (argc == 0)
1099 cmdentry.special = 1;
1100 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
1101 if (argc > 0)
1102 bltinsetlocale();
1103 commandname = argv[0];
1104 argptr = argv + 1;
1105 nextopt_optptr = NULL; /* initialize nextopt */
1106 builtin_flags = flags;
1107 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
1108 flushall();
1109 if (outiserror(out1)) {
1110 warning("write error on stdout");
1111 if (exitstatus == 0 || exitstatus == 1)
1112 exitstatus = 2;
1113 }
1114 cmddone:
1115 if (argc > 0)
1116 bltinunsetlocale();
1117 cmdenviron = NULL;
1118 out1 = &output;
1119 out2 = &errout;
1120 freestdout();
1121 handler = savehandler;
1122 commandname = savecmdname;
1123 if (jp)
1124 exitshell(exitstatus);
1125 if (flags == EV_BACKCMD) {
1126 backcmd->buf = memout.buf;
1127 backcmd->nleft = memout.buf != NULL ?
1128 memout.nextc - memout.buf : 0;
1129 memout.buf = NULL;
1130 memout.nextc = NULL;
1131 memout.bufend = NULL;
1132 memout.bufsize = 64;
1133 }
1134 if (cmdentry.u.index != EXECCMD)
1135 popredir();
1136 if (e != -1) {
1137 if (e != EXERROR || cmdentry.special)
1138 exraise(e);
1139 popfilesupto(savetopfile);
1140 if (flags != EV_BACKCMD)
1141 FORCEINTON;
1142 }
1143 } else {
1144 #ifdef DEBUG
1145 trputs("normal command: "); trargs(argv);
1146 #endif
1147 redirect(cmd->ncmd.redirect, 0);
1148 for (i = 0; i < varlist.count; i++)
1149 setvareq(varlist.args[i], VEXPORT|VSTACK);
1150 envp = environment();
1151 shellexec(argv, envp, path, cmdentry.u.index);
1152 /*NOTREACHED*/
1153 }
1154 goto out;
1155
1156 parent: /* parent process gets here (if we forked) */
1157 if (mode == FORK_FG) { /* argument to fork */
1158 INTOFF;
1159 exitstatus = waitforjob(jp, &signaled);
1160 INTON;
1161 if (iflag && loopnest > 0 && signaled) {
1162 evalskip = SKIPBREAK;
1163 skipcount = loopnest;
1164 }
1165 } else if (mode == FORK_NOJOB) {
1166 backcmd->fd = pip[0];
1167 close(pip[1]);
1168 backcmd->jp = jp;
1169 }
1170
1171 out:
1172 if (lastarg)
1173 setvar("_", lastarg, 0);
1174 if (do_clearcmdentry)
1175 clearcmdentry();
1176 }
1177
1178
1179
1180 /*
1181 * Search for a command. This is called before we fork so that the
1182 * location of the command will be available in the parent as well as
1183 * the child. The check for "goodname" is an overly conservative
1184 * check that the name will not be subject to expansion.
1185 */
1186
1187 static void
prehash(union node * n)1188 prehash(union node *n)
1189 {
1190 struct cmdentry entry;
1191
1192 if (n && n->type == NCMD && n->ncmd.args)
1193 if (goodname(n->ncmd.args->narg.text))
1194 find_command(n->ncmd.args->narg.text, &entry, 0,
1195 pathval());
1196 }
1197
1198
1199
1200 /*
1201 * Builtin commands. Builtin commands whose functions are closely
1202 * tied to evaluation are implemented here.
1203 */
1204
1205 /*
1206 * No command given, a bltin command with no arguments, or a bltin command
1207 * with an invalid name.
1208 */
1209
1210 int
bltincmd(int argc,char ** argv)1211 bltincmd(int argc, char **argv)
1212 {
1213 if (argc > 1) {
1214 out2fmt_flush("%s: not found\n", argv[1]);
1215 return 127;
1216 }
1217 /*
1218 * Preserve exitstatus of a previous possible command substitution
1219 * as POSIX mandates
1220 */
1221 return exitstatus;
1222 }
1223
1224
1225 /*
1226 * Handle break and continue commands. Break, continue, and return are
1227 * all handled by setting the evalskip flag. The evaluation routines
1228 * above all check this flag, and if it is set they start skipping
1229 * commands rather than executing them. The variable skipcount is
1230 * the number of loops to break/continue, or the number of function
1231 * levels to return. (The latter is always 1.) It should probably
1232 * be an error to break out of more loops than exist, but it isn't
1233 * in the standard shell so we don't make it one here.
1234 */
1235
1236 int
breakcmd(int argc,char ** argv)1237 breakcmd(int argc, char **argv)
1238 {
1239 long n;
1240 char *end;
1241
1242 if (argc > 1) {
1243 /* Allow arbitrarily large numbers. */
1244 n = strtol(argv[1], &end, 10);
1245 if (!is_digit(argv[1][0]) || *end != '\0')
1246 error("Illegal number: %s", argv[1]);
1247 } else
1248 n = 1;
1249 if (n > loopnest)
1250 n = loopnest;
1251 if (n > 0) {
1252 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
1253 skipcount = n;
1254 }
1255 return 0;
1256 }
1257
1258 /*
1259 * The `command' command.
1260 */
1261 int
commandcmd(int argc __unused,char ** argv __unused)1262 commandcmd(int argc __unused, char **argv __unused)
1263 {
1264 const char *path;
1265 int ch;
1266 int cmd = -1;
1267
1268 path = bltinlookup("PATH", 1);
1269
1270 while ((ch = nextopt("pvV")) != '\0') {
1271 switch (ch) {
1272 case 'p':
1273 path = _PATH_STDPATH;
1274 break;
1275 case 'v':
1276 cmd = TYPECMD_SMALLV;
1277 break;
1278 case 'V':
1279 cmd = TYPECMD_BIGV;
1280 break;
1281 }
1282 }
1283
1284 if (cmd != -1) {
1285 if (*argptr == NULL || argptr[1] != NULL)
1286 error("wrong number of arguments");
1287 return typecmd_impl(2, argptr - 1, cmd, path);
1288 }
1289 if (*argptr != NULL)
1290 error("commandcmd bad call");
1291
1292 /*
1293 * Do nothing successfully if no command was specified;
1294 * ksh also does this.
1295 */
1296 return 0;
1297 }
1298
1299
1300 /*
1301 * The return command.
1302 */
1303
1304 int
returncmd(int argc,char ** argv)1305 returncmd(int argc, char **argv)
1306 {
1307 int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1308
1309 evalskip = SKIPRETURN;
1310 skipcount = 1;
1311 return ret;
1312 }
1313
1314
1315 int
falsecmd(int argc __unused,char ** argv __unused)1316 falsecmd(int argc __unused, char **argv __unused)
1317 {
1318 return 1;
1319 }
1320
1321
1322 int
truecmd(int argc __unused,char ** argv __unused)1323 truecmd(int argc __unused, char **argv __unused)
1324 {
1325 return 0;
1326 }
1327
1328
1329 int
execcmd(int argc,char ** argv)1330 execcmd(int argc, char **argv)
1331 {
1332 int i;
1333
1334 /*
1335 * Because we have historically not supported any options,
1336 * only treat "--" specially.
1337 */
1338 if (argc > 1 && strcmp(argv[1], "--") == 0)
1339 argc--, argv++;
1340 if (argc > 1) {
1341 iflag = 0; /* exit on error */
1342 mflag = 0;
1343 optschanged();
1344 for (i = 0; i < cmdenviron->count; i++)
1345 setvareq(cmdenviron->args[i], VEXPORT|VSTACK);
1346 shellexec(argv + 1, environment(), pathval(), 0);
1347
1348 }
1349 return 0;
1350 }
1351
1352
1353 int
timescmd(int argc __unused,char ** argv __unused)1354 timescmd(int argc __unused, char **argv __unused)
1355 {
1356 struct rusage ru;
1357 long shumins, shsmins, chumins, chsmins;
1358 double shusecs, shssecs, chusecs, chssecs;
1359
1360 if (getrusage(RUSAGE_SELF, &ru) < 0)
1361 return 1;
1362 shumins = ru.ru_utime.tv_sec / 60;
1363 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1364 shsmins = ru.ru_stime.tv_sec / 60;
1365 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1366 if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1367 return 1;
1368 chumins = ru.ru_utime.tv_sec / 60;
1369 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1370 chsmins = ru.ru_stime.tv_sec / 60;
1371 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1372 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1373 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1374 return 0;
1375 }
1376