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 "myhistedit.h"
67 #endif
68
69
70 int evalskip; /* set if we are skipping commands */
71 int skipcount; /* number of levels to skip */
72 static int loopnest; /* current loop nesting level */
73 int funcnest; /* depth of function calls */
74 static int builtin_flags; /* evalcommand flags for builtins */
75
76
77 char *commandname;
78 struct arglist *cmdenviron;
79 int exitstatus; /* exit status of last command */
80 int oexitstatus; /* saved exit status */
81
82
83 static void evalloop(union node *, int);
84 static void evalfor(union node *, int);
85 static union node *evalcase(union node *);
86 static void evalsubshell(union node *, int);
87 static void evalredir(union node *, int);
88 static void exphere(union node *, struct arglist *);
89 static void expredir(union node *);
90 static void evalpipe(union node *);
91 static int is_valid_fast_cmdsubst(union node *n);
92 static void evalcommand(union node *, int, struct backcmd *);
93 static void prehash(union node *);
94
95
96 /*
97 * Called to reset things after an exception.
98 */
99
100 void
reseteval(void)101 reseteval(void)
102 {
103 evalskip = 0;
104 loopnest = 0;
105 }
106
107
108 /*
109 * The eval command.
110 */
111
112 int
evalcmd(int argc,char ** argv)113 evalcmd(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
144 void
evalstring(const char * s,int flags)145 evalstring(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, 1);
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
184 void
evaltree(union node * n,int flags)185 evaltree(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);
295 out:
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
306 static void
evalloop(union node * n,int flags)307 evalloop(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
343 static void
evalfor(union node * n,int flags)344 evalfor(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
384 static union node *
evalcase(union node * n)385 evalcase(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
420 static void
evalsubshell(union node * n,int flags)421 evalsubshell(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
447 static void
evalredir(union node * n,int flags)448 evalredir(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
483 static void
exphere(union node * redir,struct arglist * fn)484 exphere(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
521 static void
expredir(union node * n)522 expredir(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
561 static void
evalpipe(union node * n)562 evalpipe(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
621 static int
is_valid_fast_cmdsubst(union node * n)622 is_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
635 void
evalbackcmd(union node * n,struct backcmd * result)636 evalbackcmd(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
704 static int
mustexpandto(const char * argtext,const char * mask)705 mustexpandto(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
725 static int
isdeclarationcmd(struct narg * arg)726 isdeclarationcmd(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
750 static void
xtracecommand(struct arglist * varlist,int argc,char ** argv)751 xtracecommand(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 */
790 static int
safe_builtin(int idx,int argc,char ** argv)791 safe_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 * Execute a simple command.
808 * Note: This may or may not return if (flags & EV_EXIT).
809 */
810
811 static void
evalcommand(union node * cmd,int flags,struct backcmd * backcmd)812 evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
813 {
814 union node *argp;
815 struct arglist arglist;
816 struct arglist varlist;
817 char **argv;
818 int argc;
819 char **envp;
820 int varflag;
821 int mode;
822 int pip[2];
823 struct cmdentry cmdentry;
824 struct job *jp;
825 struct jmploc jmploc;
826 struct jmploc *savehandler;
827 char *savecmdname;
828 struct shparam saveparam;
829 struct localvar *savelocalvars;
830 struct parsefile *savetopfile;
831 volatile int e;
832 char *lastarg;
833 int signaled;
834 int do_clearcmdentry;
835 const char *path = pathval();
836 int i;
837
838 /* First expand the arguments. */
839 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
840 emptyarglist(&arglist);
841 emptyarglist(&varlist);
842 varflag = 1;
843 jp = NULL;
844 do_clearcmdentry = 0;
845 oexitstatus = exitstatus;
846 exitstatus = 0;
847 /* Add one slot at the beginning for tryexec(). */
848 appendarglist(&arglist, nullstr);
849 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
850 if (varflag && isassignment(argp->narg.text)) {
851 expandarg(argp, varflag == 1 ? &varlist : &arglist,
852 EXP_VARTILDE);
853 continue;
854 } else if (varflag == 1)
855 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
856 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
857 }
858 appendarglist(&arglist, nullstr);
859 expredir(cmd->ncmd.redirect);
860 argc = arglist.count - 2;
861 argv = &arglist.args[1];
862
863 argv[argc] = NULL;
864 lastarg = NULL;
865 if (iflag && funcnest == 0 && argc > 0)
866 lastarg = argv[argc - 1];
867
868 /* Print the command if xflag is set. */
869 if (xflag)
870 xtracecommand(&varlist, argc, argv);
871
872 /* Now locate the command. */
873 if (argc == 0) {
874 /* Variable assignment(s) without command */
875 cmdentry.cmdtype = CMDBUILTIN;
876 cmdentry.u.index = BLTINCMD;
877 cmdentry.special = 0;
878 } else {
879 static const char PATH[] = "PATH=";
880 int cmd_flags = 0, bltinonly = 0;
881
882 /*
883 * Modify the command lookup path, if a PATH= assignment
884 * is present
885 */
886 for (i = 0; i < varlist.count; i++)
887 if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) {
888 path = varlist.args[i] + sizeof(PATH) - 1;
889 /*
890 * On `PATH=... command`, we need to make
891 * sure that the command isn't using the
892 * non-updated hash table of the outer PATH
893 * setting and we need to make sure that
894 * the hash table isn't filled with items
895 * from the temporary setting.
896 *
897 * It would be better to forbid using and
898 * updating the table while this command
899 * runs, by the command finding mechanism
900 * is heavily integrated with hash handling,
901 * so we just delete the hash before and after
902 * the command runs. Partly deleting like
903 * changepatch() does doesn't seem worth the
904 * booking effort, since most such runs add
905 * directories in front of the new PATH.
906 */
907 clearcmdentry();
908 do_clearcmdentry = 1;
909 }
910
911 for (;;) {
912 if (bltinonly) {
913 cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
914 if (cmdentry.u.index < 0) {
915 cmdentry.u.index = BLTINCMD;
916 argv--;
917 argc++;
918 break;
919 }
920 } else
921 find_command(argv[0], &cmdentry, cmd_flags, path);
922 /* implement the bltin and command builtins here */
923 if (cmdentry.cmdtype != CMDBUILTIN)
924 break;
925 if (cmdentry.u.index == BLTINCMD) {
926 if (argc == 1)
927 break;
928 argv++;
929 argc--;
930 bltinonly = 1;
931 } else if (cmdentry.u.index == COMMANDCMD) {
932 if (argc == 1)
933 break;
934 if (!strcmp(argv[1], "-p")) {
935 if (argc == 2)
936 break;
937 if (argv[2][0] == '-') {
938 if (strcmp(argv[2], "--"))
939 break;
940 if (argc == 3)
941 break;
942 argv += 3;
943 argc -= 3;
944 } else {
945 argv += 2;
946 argc -= 2;
947 }
948 path = _PATH_STDPATH;
949 clearcmdentry();
950 do_clearcmdentry = 1;
951 } else if (!strcmp(argv[1], "--")) {
952 if (argc == 2)
953 break;
954 argv += 2;
955 argc -= 2;
956 } else if (argv[1][0] == '-')
957 break;
958 else {
959 argv++;
960 argc--;
961 }
962 cmd_flags |= DO_NOFUNC;
963 bltinonly = 0;
964 } else
965 break;
966 }
967 /*
968 * Special builtins lose their special properties when
969 * called via 'command'.
970 */
971 if (cmd_flags & DO_NOFUNC)
972 cmdentry.special = 0;
973 }
974
975 /* Fork off a child process if necessary. */
976 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
977 && ((flags & EV_EXIT) == 0 || have_traps()))
978 || ((flags & EV_BACKCMD) != 0
979 && (cmdentry.cmdtype != CMDBUILTIN ||
980 !safe_builtin(cmdentry.u.index, argc, argv)))) {
981 jp = makejob(cmd, 1);
982 mode = FORK_FG;
983 if (flags & EV_BACKCMD) {
984 mode = FORK_NOJOB;
985 if (pipe(pip) < 0)
986 error("Pipe call failed: %s", strerror(errno));
987 }
988 if (cmdentry.cmdtype == CMDNORMAL &&
989 cmd->ncmd.redirect == NULL &&
990 varlist.count == 0 &&
991 (mode == FORK_FG || mode == FORK_NOJOB) &&
992 !disvforkset() && !iflag && !mflag) {
993 vforkexecshell(jp, argv, environment(), path,
994 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL);
995 goto parent;
996 }
997 if (forkshell(jp, cmd, mode) != 0)
998 goto parent; /* at end of routine */
999 if (flags & EV_BACKCMD) {
1000 FORCEINTON;
1001 close(pip[0]);
1002 if (pip[1] != 1) {
1003 dup2(pip[1], 1);
1004 close(pip[1]);
1005 }
1006 flags &= ~EV_BACKCMD;
1007 }
1008 flags |= EV_EXIT;
1009 }
1010
1011 /* This is the child process if a fork occurred. */
1012 /* Execute the command. */
1013 if (cmdentry.cmdtype == CMDFUNCTION) {
1014 #ifdef DEBUG
1015 trputs("Shell function: "); trargs(argv);
1016 #endif
1017 saveparam = shellparam;
1018 shellparam.malloc = 0;
1019 shellparam.reset = 1;
1020 shellparam.nparam = argc - 1;
1021 shellparam.p = argv + 1;
1022 shellparam.optp = NULL;
1023 shellparam.optnext = NULL;
1024 INTOFF;
1025 savelocalvars = localvars;
1026 localvars = NULL;
1027 reffunc(cmdentry.u.func);
1028 savehandler = handler;
1029 if (setjmp(jmploc.loc)) {
1030 popredir();
1031 unreffunc(cmdentry.u.func);
1032 poplocalvars();
1033 localvars = savelocalvars;
1034 freeparam(&shellparam);
1035 shellparam = saveparam;
1036 funcnest--;
1037 handler = savehandler;
1038 longjmp(handler->loc, 1);
1039 }
1040 handler = &jmploc;
1041 funcnest++;
1042 redirect(cmd->ncmd.redirect, REDIR_PUSH);
1043 INTON;
1044 for (i = 0; i < varlist.count; i++)
1045 mklocal(varlist.args[i]);
1046 exitstatus = oexitstatus;
1047 evaltree(getfuncnode(cmdentry.u.func),
1048 flags & (EV_TESTED | EV_EXIT));
1049 INTOFF;
1050 unreffunc(cmdentry.u.func);
1051 poplocalvars();
1052 localvars = savelocalvars;
1053 freeparam(&shellparam);
1054 shellparam = saveparam;
1055 handler = savehandler;
1056 funcnest--;
1057 popredir();
1058 INTON;
1059 if (evalskip == SKIPRETURN) {
1060 evalskip = 0;
1061 skipcount = 0;
1062 }
1063 if (jp)
1064 exitshell(exitstatus);
1065 } else if (cmdentry.cmdtype == CMDBUILTIN) {
1066 #ifdef DEBUG
1067 trputs("builtin command: "); trargs(argv);
1068 #endif
1069 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
1070 if (flags == EV_BACKCMD) {
1071 memout.nextc = memout.buf;
1072 mode |= REDIR_BACKQ;
1073 }
1074 savecmdname = commandname;
1075 savetopfile = getcurrentfile();
1076 cmdenviron = &varlist;
1077 e = -1;
1078 savehandler = handler;
1079 if (setjmp(jmploc.loc)) {
1080 e = exception;
1081 if (e == EXINT)
1082 exitstatus = SIGINT+128;
1083 goto cmddone;
1084 }
1085 handler = &jmploc;
1086 redirect(cmd->ncmd.redirect, mode);
1087 outclearerror(out1);
1088 /*
1089 * If there is no command word, redirection errors should
1090 * not be fatal but assignment errors should.
1091 */
1092 if (argc == 0)
1093 cmdentry.special = 1;
1094 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
1095 if (argc > 0)
1096 bltinsetlocale();
1097 commandname = argv[0];
1098 argptr = argv + 1;
1099 nextopt_optptr = NULL; /* initialize nextopt */
1100 builtin_flags = flags;
1101 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
1102 flushall();
1103 if (outiserror(out1)) {
1104 warning("write error on stdout");
1105 if (exitstatus == 0 || exitstatus == 1)
1106 exitstatus = 2;
1107 }
1108 cmddone:
1109 if (argc > 0)
1110 bltinunsetlocale();
1111 cmdenviron = NULL;
1112 out1 = &output;
1113 out2 = &errout;
1114 freestdout();
1115 handler = savehandler;
1116 commandname = savecmdname;
1117 if (jp)
1118 exitshell(exitstatus);
1119 if (flags == EV_BACKCMD) {
1120 backcmd->buf = memout.buf;
1121 backcmd->nleft = memout.buf != NULL ?
1122 memout.nextc - memout.buf : 0;
1123 memout.buf = NULL;
1124 memout.nextc = NULL;
1125 memout.bufend = NULL;
1126 memout.bufsize = 64;
1127 }
1128 if (cmdentry.u.index != EXECCMD)
1129 popredir();
1130 if (e != -1) {
1131 if (e != EXERROR || cmdentry.special)
1132 exraise(e);
1133 popfilesupto(savetopfile);
1134 if (flags != EV_BACKCMD)
1135 FORCEINTON;
1136 }
1137 } else {
1138 #ifdef DEBUG
1139 trputs("normal command: "); trargs(argv);
1140 #endif
1141 redirect(cmd->ncmd.redirect, 0);
1142 for (i = 0; i < varlist.count; i++)
1143 setvareq(varlist.args[i], VEXPORT|VSTACK);
1144 envp = environment();
1145 shellexec(argv, envp, path, cmdentry.u.index);
1146 /*NOTREACHED*/
1147 }
1148 goto out;
1149
1150 parent: /* parent process gets here (if we forked) */
1151 if (mode == FORK_FG) { /* argument to fork */
1152 INTOFF;
1153 exitstatus = waitforjob(jp, &signaled);
1154 INTON;
1155 if (iflag && loopnest > 0 && signaled) {
1156 evalskip = SKIPBREAK;
1157 skipcount = loopnest;
1158 }
1159 } else if (mode == FORK_NOJOB) {
1160 backcmd->fd = pip[0];
1161 close(pip[1]);
1162 backcmd->jp = jp;
1163 }
1164
1165 out:
1166 if (lastarg)
1167 setvar("_", lastarg, 0);
1168 if (do_clearcmdentry)
1169 clearcmdentry();
1170 }
1171
1172
1173
1174 /*
1175 * Search for a command. This is called before we fork so that the
1176 * location of the command will be available in the parent as well as
1177 * the child. The check for "goodname" is an overly conservative
1178 * check that the name will not be subject to expansion.
1179 */
1180
1181 static void
prehash(union node * n)1182 prehash(union node *n)
1183 {
1184 struct cmdentry entry;
1185
1186 if (n && n->type == NCMD && n->ncmd.args)
1187 if (goodname(n->ncmd.args->narg.text))
1188 find_command(n->ncmd.args->narg.text, &entry, 0,
1189 pathval());
1190 }
1191
1192
1193
1194 /*
1195 * Builtin commands. Builtin commands whose functions are closely
1196 * tied to evaluation are implemented here.
1197 */
1198
1199 /*
1200 * No command given, a bltin command with no arguments, or a bltin command
1201 * with an invalid name.
1202 */
1203
1204 int
bltincmd(int argc,char ** argv)1205 bltincmd(int argc, char **argv)
1206 {
1207 if (argc > 1) {
1208 out2fmt_flush("%s: not found\n", argv[1]);
1209 return 127;
1210 }
1211 /*
1212 * Preserve exitstatus of a previous possible command substitution
1213 * as POSIX mandates
1214 */
1215 return exitstatus;
1216 }
1217
1218
1219 /*
1220 * Handle break and continue commands. Break, continue, and return are
1221 * all handled by setting the evalskip flag. The evaluation routines
1222 * above all check this flag, and if it is set they start skipping
1223 * commands rather than executing them. The variable skipcount is
1224 * the number of loops to break/continue, or the number of function
1225 * levels to return. (The latter is always 1.) It should probably
1226 * be an error to break out of more loops than exist, but it isn't
1227 * in the standard shell so we don't make it one here.
1228 */
1229
1230 int
breakcmd(int argc,char ** argv)1231 breakcmd(int argc, char **argv)
1232 {
1233 long n;
1234 char *end;
1235
1236 if (argc > 1) {
1237 /* Allow arbitrarily large numbers. */
1238 n = strtol(argv[1], &end, 10);
1239 if (!is_digit(argv[1][0]) || *end != '\0')
1240 error("Illegal number: %s", argv[1]);
1241 } else
1242 n = 1;
1243 if (n > loopnest)
1244 n = loopnest;
1245 if (n > 0) {
1246 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
1247 skipcount = n;
1248 }
1249 return 0;
1250 }
1251
1252 /*
1253 * The `command' command.
1254 */
1255 int
commandcmd(int argc __unused,char ** argv __unused)1256 commandcmd(int argc __unused, char **argv __unused)
1257 {
1258 const char *path;
1259 int ch;
1260 int cmd = -1;
1261
1262 path = bltinlookup("PATH", 1);
1263
1264 while ((ch = nextopt("pvV")) != '\0') {
1265 switch (ch) {
1266 case 'p':
1267 path = _PATH_STDPATH;
1268 break;
1269 case 'v':
1270 cmd = TYPECMD_SMALLV;
1271 break;
1272 case 'V':
1273 cmd = TYPECMD_BIGV;
1274 break;
1275 }
1276 }
1277
1278 if (cmd != -1) {
1279 if (*argptr == NULL || argptr[1] != NULL)
1280 error("wrong number of arguments");
1281 return typecmd_impl(2, argptr - 1, cmd, path);
1282 }
1283 if (*argptr != NULL)
1284 error("commandcmd bad call");
1285
1286 /*
1287 * Do nothing successfully if no command was specified;
1288 * ksh also does this.
1289 */
1290 return 0;
1291 }
1292
1293
1294 /*
1295 * The return command.
1296 */
1297
1298 int
returncmd(int argc,char ** argv)1299 returncmd(int argc, char **argv)
1300 {
1301 int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1302
1303 evalskip = SKIPRETURN;
1304 skipcount = 1;
1305 return ret;
1306 }
1307
1308
1309 int
falsecmd(int argc __unused,char ** argv __unused)1310 falsecmd(int argc __unused, char **argv __unused)
1311 {
1312 return 1;
1313 }
1314
1315
1316 int
truecmd(int argc __unused,char ** argv __unused)1317 truecmd(int argc __unused, char **argv __unused)
1318 {
1319 return 0;
1320 }
1321
1322
1323 int
execcmd(int argc,char ** argv)1324 execcmd(int argc, char **argv)
1325 {
1326 int i;
1327
1328 /*
1329 * Because we have historically not supported any options,
1330 * only treat "--" specially.
1331 */
1332 if (argc > 1 && strcmp(argv[1], "--") == 0)
1333 argc--, argv++;
1334 if (argc > 1) {
1335 iflag = 0; /* exit on error */
1336 mflag = 0;
1337 optschanged();
1338 for (i = 0; i < cmdenviron->count; i++)
1339 setvareq(cmdenviron->args[i], VEXPORT|VSTACK);
1340 shellexec(argv + 1, environment(), pathval(), 0);
1341
1342 }
1343 return 0;
1344 }
1345
1346
1347 int
timescmd(int argc __unused,char ** argv __unused)1348 timescmd(int argc __unused, char **argv __unused)
1349 {
1350 struct rusage ru;
1351 long shumins, shsmins, chumins, chsmins;
1352 double shusecs, shssecs, chusecs, chssecs;
1353
1354 if (getrusage(RUSAGE_SELF, &ru) < 0)
1355 return 1;
1356 shumins = ru.ru_utime.tv_sec / 60;
1357 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1358 shsmins = ru.ru_stime.tv_sec / 60;
1359 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1360 if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1361 return 1;
1362 chumins = ru.ru_utime.tv_sec / 60;
1363 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1364 chsmins = ru.ru_stime.tv_sec / 60;
1365 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1366 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1367 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1368 return 0;
1369 }
1370