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