sh - Sync to FreeBSD d038ee76 part 1/2
[dragonfly.git] / bin / sh / eval.c
1 /*-
2  * Copyright (c) 1993
3  *      The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Kenneth Almquist.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 4. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32
33 #ifndef lint
34 #if 0
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("$FreeBSD$");
40
41 #include <paths.h>
42 #include <signal.h>
43 #include <stdlib.h>
44 #include <unistd.h>
45 #include <sys/resource.h>
46 #include <sys/wait.h> /* For WIFSIGNALED(status) */
47 #include <errno.h>
48
49 /*
50  * Evaluate a command.
51  */
52
53 #include "shell.h"
54 #include "nodes.h"
55 #include "syntax.h"
56 #include "expand.h"
57 #include "parser.h"
58 #include "jobs.h"
59 #include "eval.h"
60 #include "builtins.h"
61 #include "options.h"
62 #include "exec.h"
63 #include "redir.h"
64 #include "input.h"
65 #include "output.h"
66 #include "trap.h"
67 #include "var.h"
68 #include "memalloc.h"
69 #include "error.h"
70 #include "show.h"
71 #include "mystring.h"
72 #ifndef NO_HISTORY
73 #include "myhistedit.h"
74 #endif
75
76
77 int evalskip;                   /* set if we are skipping commands */
78 int skipcount;                  /* number of levels to skip */
79 static int loopnest;            /* current loop nesting level */
80 int funcnest;                   /* depth of function calls */
81 static int builtin_flags;       /* evalcommand flags for builtins */
82
83
84 char *commandname;
85 struct strlist *cmdenviron;
86 int exitstatus;                 /* exit status of last command */
87 int oexitstatus;                /* saved exit status */
88
89
90 static void evalloop(union node *, int);
91 static void evalfor(union node *, int);
92 static union node *evalcase(union node *);
93 static void evalsubshell(union node *, int);
94 static void evalredir(union node *, int);
95 static void exphere(union node *, struct arglist *);
96 static void expredir(union node *);
97 static void evalpipe(union node *);
98 static int is_valid_fast_cmdsubst(union node *n);
99 static void evalcommand(union node *, int, struct backcmd *);
100 static void prehash(union node *);
101
102
103 /*
104  * Called to reset things after an exception.
105  */
106
107 void
108 reseteval(void)
109 {
110         evalskip = 0;
111         loopnest = 0;
112 }
113
114
115 /*
116  * The eval command.
117  */
118
119 int
120 evalcmd(int argc, char **argv)
121 {
122         char *p;
123         char *concat;
124         char **ap;
125
126         if (argc > 1) {
127                 p = argv[1];
128                 if (argc > 2) {
129                         STARTSTACKSTR(concat);
130                         ap = argv + 2;
131                         for (;;) {
132                                 STPUTS(p, concat);
133                                 if ((p = *ap++) == NULL)
134                                         break;
135                                 STPUTC(' ', concat);
136                         }
137                         STPUTC('\0', concat);
138                         p = grabstackstr(concat);
139                 }
140                 evalstring(p, builtin_flags);
141         } else
142                 exitstatus = 0;
143         return exitstatus;
144 }
145
146
147 /*
148  * Execute a command or commands contained in a string.
149  */
150
151 void
152 evalstring(const char *s, int flags)
153 {
154         union node *n;
155         struct stackmark smark;
156         int flags_exit;
157         int any;
158
159         flags_exit = flags & EV_EXIT;
160         flags &= ~EV_EXIT;
161         any = 0;
162         setstackmark(&smark);
163         setinputstring(s, 1);
164         while ((n = parsecmd(0)) != NEOF) {
165                 if (n != NULL && !nflag) {
166                         if (flags_exit && preadateof())
167                                 evaltree(n, flags | EV_EXIT);
168                         else
169                                 evaltree(n, flags);
170                         any = 1;
171                         if (evalskip)
172                                 break;
173                 }
174                 popstackmark(&smark);
175                 setstackmark(&smark);
176         }
177         popfile();
178         popstackmark(&smark);
179         if (!any)
180                 exitstatus = 0;
181         if (flags_exit)
182                 exraise(EXEXIT);
183 }
184
185
186 /*
187  * Evaluate a parse tree.  The value is left in the global variable
188  * exitstatus.
189  */
190
191 void
192 evaltree(union node *n, int flags)
193 {
194         int do_etest;
195         union node *next;
196         struct stackmark smark;
197
198         setstackmark(&smark);
199         do_etest = 0;
200         if (n == NULL) {
201                 TRACE(("evaltree(NULL) called\n"));
202                 exitstatus = 0;
203                 goto out;
204         }
205         do {
206                 next = NULL;
207 #ifndef NO_HISTORY
208                 displayhist = 1;        /* show history substitutions done with fc */
209 #endif
210                 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
211                 switch (n->type) {
212                 case NSEMI:
213                         evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
214                         if (evalskip)
215                                 goto out;
216                         next = n->nbinary.ch2;
217                         break;
218                 case NAND:
219                         evaltree(n->nbinary.ch1, EV_TESTED);
220                         if (evalskip || exitstatus != 0) {
221                                 goto out;
222                         }
223                         next = n->nbinary.ch2;
224                         break;
225                 case NOR:
226                         evaltree(n->nbinary.ch1, EV_TESTED);
227                         if (evalskip || exitstatus == 0)
228                                 goto out;
229                         next = n->nbinary.ch2;
230                         break;
231                 case NREDIR:
232                         evalredir(n, flags);
233                         break;
234                 case NSUBSHELL:
235                         evalsubshell(n, flags);
236                         do_etest = !(flags & EV_TESTED);
237                         break;
238                 case NBACKGND:
239                         evalsubshell(n, flags);
240                         break;
241                 case NIF: {
242                         evaltree(n->nif.test, EV_TESTED);
243                         if (evalskip)
244                                 goto out;
245                         if (exitstatus == 0)
246                                 next = n->nif.ifpart;
247                         else if (n->nif.elsepart)
248                                 next = n->nif.elsepart;
249                         else
250                                 exitstatus = 0;
251                         break;
252                 }
253                 case NWHILE:
254                 case NUNTIL:
255                         evalloop(n, flags & ~EV_EXIT);
256                         break;
257                 case NFOR:
258                         evalfor(n, flags & ~EV_EXIT);
259                         break;
260                 case NCASE:
261                         next = evalcase(n);
262                         break;
263                 case NCLIST:
264                         next = n->nclist.body;
265                         break;
266                 case NCLISTFALLTHRU:
267                         if (n->nclist.body) {
268                                 evaltree(n->nclist.body, flags & ~EV_EXIT);
269                                 if (evalskip)
270                                         goto out;
271                         }
272                         next = n->nclist.next;
273                         break;
274                 case NDEFUN:
275                         defun(n->narg.text, n->narg.next);
276                         exitstatus = 0;
277                         break;
278                 case NNOT:
279                         evaltree(n->nnot.com, EV_TESTED);
280                         if (evalskip)
281                                 goto out;
282                         exitstatus = !exitstatus;
283                         break;
284
285                 case NPIPE:
286                         evalpipe(n);
287                         do_etest = !(flags & EV_TESTED);
288                         break;
289                 case NCMD:
290                         evalcommand(n, flags, (struct backcmd *)NULL);
291                         do_etest = !(flags & EV_TESTED);
292                         break;
293                 default:
294                         out1fmt("Node type = %d\n", n->type);
295                         flushout(&output);
296                         break;
297                 }
298                 n = next;
299                 popstackmark(&smark);
300                 setstackmark(&smark);
301         } while (n != NULL);
302 out:
303         popstackmark(&smark);
304         if (pendingsig)
305                 dotrap();
306         if (eflag && exitstatus != 0 && do_etest)
307                 exitshell(exitstatus);
308         if (flags & EV_EXIT)
309                 exraise(EXEXIT);
310 }
311
312
313 static void
314 evalloop(union node *n, int flags)
315 {
316         int status;
317
318         loopnest++;
319         status = 0;
320         for (;;) {
321                 if (!evalskip)
322                 evaltree(n->nbinary.ch1, EV_TESTED);
323                 if (evalskip) {
324                         if (evalskip == SKIPCONT && --skipcount <= 0) {
325                                 evalskip = 0;
326                                 continue;
327                         }
328                         if (evalskip == SKIPBREAK && --skipcount <= 0)
329                                 evalskip = 0;
330                         if (evalskip == SKIPRETURN)
331                                 status = exitstatus;
332                         break;
333                 }
334                 if (n->type == NWHILE) {
335                         if (exitstatus != 0)
336                                 break;
337                 } else {
338                         if (exitstatus == 0)
339                                 break;
340                 }
341                 evaltree(n->nbinary.ch2, flags);
342                 status = exitstatus;
343         }
344         loopnest--;
345         exitstatus = status;
346 }
347
348
349
350 static void
351 evalfor(union node *n, int flags)
352 {
353         struct arglist arglist;
354         union node *argp;
355         struct strlist *sp;
356         int status;
357
358         arglist.lastp = &arglist.list;
359         for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
360                 oexitstatus = exitstatus;
361                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
362         }
363         *arglist.lastp = NULL;
364
365         loopnest++;
366         status = 0;
367         for (sp = arglist.list ; sp ; sp = sp->next) {
368                 setvar(n->nfor.var, sp->text, 0);
369                 evaltree(n->nfor.body, flags);
370                 status = exitstatus;
371                 if (evalskip) {
372                         if (evalskip == SKIPCONT && --skipcount <= 0) {
373                                 evalskip = 0;
374                                 continue;
375                         }
376                         if (evalskip == SKIPBREAK && --skipcount <= 0)
377                                 evalskip = 0;
378                         break;
379                 }
380         }
381         loopnest--;
382         exitstatus = status;
383 }
384
385
386 /*
387  * Evaluate a case statement, returning the selected tree.
388  *
389  * The exit status needs care to get right.
390  */
391
392 static union node *
393 evalcase(union node *n)
394 {
395         union node *cp;
396         union node *patp;
397         struct arglist arglist;
398
399         arglist.lastp = &arglist.list;
400         oexitstatus = exitstatus;
401         expandarg(n->ncase.expr, &arglist, EXP_TILDE);
402         for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) {
403                 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
404                         if (casematch(patp, arglist.list->text)) {
405                                 while (cp->nclist.next &&
406                                     cp->type == NCLISTFALLTHRU &&
407                                     cp->nclist.body == NULL)
408                                         cp = cp->nclist.next;
409                                 if (cp->nclist.next &&
410                                     cp->type == NCLISTFALLTHRU)
411                                         return (cp);
412                                 if (cp->nclist.body == NULL)
413                                         exitstatus = 0;
414                                 return (cp->nclist.body);
415                         }
416                 }
417         }
418         exitstatus = 0;
419         return (NULL);
420 }
421
422
423
424 /*
425  * Kick off a subshell to evaluate a tree.
426  */
427
428 static void
429 evalsubshell(union node *n, int flags)
430 {
431         struct job *jp;
432         int backgnd = (n->type == NBACKGND);
433
434         oexitstatus = exitstatus;
435         expredir(n->nredir.redirect);
436         if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
437             forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
438                 if (backgnd)
439                         flags &=~ EV_TESTED;
440                 redirect(n->nredir.redirect, 0);
441                 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
442         } else if (!backgnd) {
443                 INTOFF;
444                 exitstatus = waitforjob(jp, (int *)NULL);
445                 INTON;
446         } else
447                 exitstatus = 0;
448 }
449
450
451 /*
452  * Evaluate a redirected compound command.
453  */
454
455 static void
456 evalredir(union node *n, int flags)
457 {
458         struct jmploc jmploc;
459         struct jmploc *savehandler;
460         volatile int in_redirect = 1;
461
462         oexitstatus = exitstatus;
463         expredir(n->nredir.redirect);
464         savehandler = handler;
465         if (setjmp(jmploc.loc)) {
466                 int e;
467
468                 handler = savehandler;
469                 e = exception;
470                 popredir();
471                 if (e == EXERROR || e == EXEXEC) {
472                         if (in_redirect) {
473                                 exitstatus = 2;
474                                 return;
475                         }
476                 }
477                 longjmp(handler->loc, 1);
478         } else {
479                 INTOFF;
480                 handler = &jmploc;
481                 redirect(n->nredir.redirect, REDIR_PUSH);
482                 in_redirect = 0;
483                 INTON;
484                 evaltree(n->nredir.n, flags);
485         }
486         INTOFF;
487         handler = savehandler;
488         popredir();
489         INTON;
490 }
491
492
493 static void
494 exphere(union node *redir, struct arglist *fn)
495 {
496         struct jmploc jmploc;
497         struct jmploc *savehandler;
498         struct localvar *savelocalvars;
499         int need_longjmp = 0;
500
501         redir->nhere.expdoc = "";
502         savelocalvars = localvars;
503         localvars = NULL;
504         forcelocal++;
505         savehandler = handler;
506         if (setjmp(jmploc.loc))
507                 need_longjmp = exception != EXERROR && exception != EXEXEC;
508         else {
509                 handler = &jmploc;
510                 expandarg(redir->nhere.doc, fn, 0);
511                 redir->nhere.expdoc = fn->list->text;
512                 INTOFF;
513         }
514         handler = savehandler;
515         forcelocal--;
516         poplocalvars();
517         localvars = savelocalvars;
518         if (need_longjmp)
519                 longjmp(handler->loc, 1);
520         INTON;
521 }
522
523
524 /*
525  * Compute the names of the files in a redirection list.
526  */
527
528 static void
529 expredir(union node *n)
530 {
531         union node *redir;
532
533         for (redir = n ; redir ; redir = redir->nfile.next) {
534                 struct arglist fn;
535                 fn.lastp = &fn.list;
536                 switch (redir->type) {
537                 case NFROM:
538                 case NTO:
539                 case NFROMTO:
540                 case NAPPEND:
541                 case NCLOBBER:
542                         expandarg(redir->nfile.fname, &fn, EXP_TILDE);
543                         redir->nfile.expfname = fn.list->text;
544                         break;
545                 case NFROMFD:
546                 case NTOFD:
547                         if (redir->ndup.vname) {
548                                 expandarg(redir->ndup.vname, &fn, EXP_TILDE);
549                                 fixredir(redir, fn.list->text, 1);
550                         }
551                         break;
552                 case NXHERE:
553                         exphere(redir, &fn);
554                         break;
555                 }
556         }
557 }
558
559
560
561 /*
562  * Evaluate a pipeline.  All the processes in the pipeline are children
563  * of the process creating the pipeline.  (This differs from some versions
564  * of the shell, which make the last process in a pipeline the parent
565  * of all the rest.)
566  */
567
568 static void
569 evalpipe(union node *n)
570 {
571         struct job *jp;
572         struct nodelist *lp;
573         int pipelen;
574         int prevfd;
575         int pip[2];
576
577         TRACE(("evalpipe(%p) called\n", (void *)n));
578         pipelen = 0;
579         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
580                 pipelen++;
581         INTOFF;
582         jp = makejob(n, pipelen);
583         prevfd = -1;
584         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
585                 prehash(lp->n);
586                 pip[1] = -1;
587                 if (lp->next) {
588                         if (pipe(pip) < 0) {
589                                 if (prevfd >= 0)
590                                         close(prevfd);
591                                 error("Pipe call failed: %s", strerror(errno));
592                         }
593                 }
594                 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
595                         INTON;
596                         if (prevfd > 0) {
597                                 dup2(prevfd, 0);
598                                 close(prevfd);
599                         }
600                         if (pip[1] >= 0) {
601                                 if (!(prevfd >= 0 && pip[0] == 0))
602                                         close(pip[0]);
603                                 if (pip[1] != 1) {
604                                         dup2(pip[1], 1);
605                                         close(pip[1]);
606                                 }
607                         }
608                         evaltree(lp->n, EV_EXIT);
609                 }
610                 if (prevfd >= 0)
611                         close(prevfd);
612                 prevfd = pip[0];
613                 if (pip[1] != -1)
614                         close(pip[1]);
615         }
616         INTON;
617         if (n->npipe.backgnd == 0) {
618                 INTOFF;
619                 exitstatus = waitforjob(jp, (int *)NULL);
620                 TRACE(("evalpipe:  job done exit status %d\n", exitstatus));
621                 INTON;
622         } else
623                 exitstatus = 0;
624 }
625
626
627
628 static int
629 is_valid_fast_cmdsubst(union node *n)
630 {
631
632         return (n->type == NCMD);
633 }
634
635 /*
636  * Execute a command inside back quotes.  If it's a builtin command, we
637  * want to save its output in a block obtained from malloc.  Otherwise
638  * we fork off a subprocess and get the output of the command via a pipe.
639  * Should be called with interrupts off.
640  */
641
642 void
643 evalbackcmd(union node *n, struct backcmd *result)
644 {
645         int pip[2];
646         struct job *jp;
647         struct stackmark smark;
648         struct jmploc jmploc;
649         struct jmploc *savehandler;
650         struct localvar *savelocalvars;
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                 forcelocal++;
666                 savehandler = handler;
667                 if (setjmp(jmploc.loc)) {
668                         if (exception == EXERROR || exception == EXEXEC)
669                                 exitstatus = 2;
670                         else if (exception != 0) {
671                                 handler = savehandler;
672                                 forcelocal--;
673                                 poplocalvars();
674                                 localvars = savelocalvars;
675                                 longjmp(handler->loc, 1);
676                         }
677                 } else {
678                         handler = &jmploc;
679                         evalcommand(n, EV_BACKCMD, result);
680                 }
681                 handler = savehandler;
682                 forcelocal--;
683                 poplocalvars();
684                 localvars = savelocalvars;
685         } else {
686                 if (pipe(pip) < 0)
687                         error("Pipe call failed: %s", strerror(errno));
688                 jp = makejob(n, 1);
689                 if (forkshell(jp, n, FORK_NOJOB) == 0) {
690                         FORCEINTON;
691                         close(pip[0]);
692                         if (pip[1] != 1) {
693                                 dup2(pip[1], 1);
694                                 close(pip[1]);
695                         }
696                         evaltree(n, EV_EXIT);
697                 }
698                 close(pip[1]);
699                 result->fd = pip[0];
700                 result->jp = jp;
701         }
702         popstackmark(&smark);
703         TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
704                 result->fd, result->buf, result->nleft, result->jp));
705 }
706
707 static int
708 mustexpandto(const char *argtext, const char *mask)
709 {
710         for (;;) {
711                 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) {
712                         argtext++;
713                         continue;
714                 }
715                 if (*argtext == CTLESC)
716                         argtext++;
717                 else if (BASESYNTAX[(int)*argtext] == CCTL)
718                         return (0);
719                 if (*argtext != *mask)
720                         return (0);
721                 if (*argtext == '\0')
722                         return (1);
723                 argtext++;
724                 mask++;
725         }
726 }
727
728 static int
729 isdeclarationcmd(struct narg *arg)
730 {
731         int have_command = 0;
732
733         if (arg == NULL)
734                 return (0);
735         while (mustexpandto(arg->text, "command")) {
736                 have_command = 1;
737                 arg = &arg->next->narg;
738                 if (arg == NULL)
739                         return (0);
740                 /*
741                  * To also allow "command -p" and "command --" as part of
742                  * a declaration command, add code here.
743                  * We do not do this, as ksh does not do it either and it
744                  * is not required by POSIX.
745                  */
746         }
747         return (mustexpandto(arg->text, "export") ||
748             mustexpandto(arg->text, "readonly") ||
749             (mustexpandto(arg->text, "local") &&
750                 (have_command || !isfunc("local"))));
751 }
752
753 static void
754 xtracecommand(struct arglist *varlist, struct arglist *arglist)
755 {
756         struct strlist *sp;
757         char sep = 0;
758         const char *p, *ps4;
759
760         ps4 = expandstr(ps4val());
761         out2str(ps4 != NULL ? ps4 : ps4val());
762         for (sp = varlist->list ; sp ; sp = sp->next) {
763                 if (sep != 0)
764                         out2c(' ');
765                 p = strchr(sp->text, '=');
766                 if (p != NULL) {
767                         p++;
768                         outbin(sp->text, p - sp->text, out2);
769                         out2qstr(p);
770                 } else
771                         out2qstr(sp->text);
772                 sep = ' ';
773         }
774         for (sp = arglist->list ; sp ; sp = sp->next) {
775                 if (sep != 0)
776                         out2c(' ');
777                 out2qstr(sp->text);
778                 sep = ' ';
779         }
780         out2c('\n');
781         flushout(&errout);
782 }
783
784 /*
785  * Check if a builtin can safely be executed in the same process,
786  * even though it should be in a subshell (command substitution).
787  * Note that jobid, jobs, times and trap can show information not
788  * available in a child process; this is deliberate.
789  * The arguments should already have been expanded.
790  */
791 static int
792 safe_builtin(int idx, int argc, char **argv)
793 {
794         if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD ||
795             idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD ||
796             idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD ||
797             idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD ||
798             idx == TYPECMD)
799                 return (1);
800         if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD ||
801             idx == UMASKCMD)
802                 return (argc <= 1 || (argc == 2 && argv[1][0] == '-'));
803         if (idx == SETCMD)
804                 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' ||
805                     argv[1][0] == '+') && argv[1][1] == 'o' &&
806                     argv[1][2] == '\0'));
807         return (0);
808 }
809
810 /*
811  * Execute a simple command.
812  * Note: This may or may not return if (flags & EV_EXIT).
813  */
814
815 static void
816 evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
817 {
818         union node *argp;
819         struct arglist arglist;
820         struct arglist varlist;
821         char **argv;
822         int argc;
823         char **envp;
824         int varflag;
825         struct strlist *sp;
826         int mode;
827         int pip[2];
828         struct cmdentry cmdentry;
829         struct job *jp;
830         struct jmploc jmploc;
831         struct jmploc *savehandler;
832         char *savecmdname;
833         struct shparam saveparam;
834         struct localvar *savelocalvars;
835         struct parsefile *savetopfile;
836         volatile int e;
837         char *lastarg;
838         int realstatus;
839         int do_clearcmdentry;
840         const char *path = pathval();
841
842         /* First expand the arguments. */
843         TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
844         arglist.lastp = &arglist.list;
845         varlist.lastp = &varlist.list;
846         varflag = 1;
847         jp = NULL;
848         do_clearcmdentry = 0;
849         oexitstatus = exitstatus;
850         exitstatus = 0;
851         for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
852                 if (varflag && isassignment(argp->narg.text)) {
853                         expandarg(argp, varflag == 1 ? &varlist : &arglist,
854                             EXP_VARTILDE);
855                         continue;
856                 } else if (varflag == 1)
857                         varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
858                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
859         }
860         *arglist.lastp = NULL;
861         *varlist.lastp = NULL;
862         expredir(cmd->ncmd.redirect);
863         argc = 0;
864         for (sp = arglist.list ; sp ; sp = sp->next)
865                 argc++;
866         /* Add one slot at the beginning for tryexec(). */
867         argv = stalloc(sizeof (char *) * (argc + 2));
868         argv++;
869
870         for (sp = arglist.list ; sp ; sp = sp->next) {
871                 TRACE(("evalcommand arg: %s\n", sp->text));
872                 *argv++ = sp->text;
873         }
874         *argv = NULL;
875         lastarg = NULL;
876         if (iflag && funcnest == 0 && argc > 0)
877                 lastarg = argv[-1];
878         argv -= argc;
879
880         /* Print the command if xflag is set. */
881         if (xflag)
882                 xtracecommand(&varlist, &arglist);
883
884         /* Now locate the command. */
885         if (argc == 0) {
886                 /* Variable assignment(s) without command */
887                 cmdentry.cmdtype = CMDBUILTIN;
888                 cmdentry.u.index = BLTINCMD;
889                 cmdentry.special = 0;
890         } else {
891                 static const char PATH[] = "PATH=";
892                 int cmd_flags = 0, bltinonly = 0;
893
894                 /*
895                  * Modify the command lookup path, if a PATH= assignment
896                  * is present
897                  */
898                 for (sp = varlist.list ; sp ; sp = sp->next)
899                         if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
900                                 path = sp->text + sizeof(PATH) - 1;
901                                 /*
902                                  * On `PATH=... command`, we need to make
903                                  * sure that the command isn't using the
904                                  * non-updated hash table of the outer PATH
905                                  * setting and we need to make sure that
906                                  * the hash table isn't filled with items
907                                  * from the temporary setting.
908                                  *
909                                  * It would be better to forbit using and
910                                  * updating the table while this command
911                                  * runs, by the command finding mechanism
912                                  * is heavily integrated with hash handling,
913                                  * so we just delete the hash before and after
914                                  * the command runs. Partly deleting like
915                                  * changepatch() does doesn't seem worth the
916                                  * bookinging effort, since most such runs add
917                                  * directories in front of the new PATH.
918                                  */
919                                 clearcmdentry();
920                                 do_clearcmdentry = 1;
921                         }
922
923                 for (;;) {
924                         if (bltinonly) {
925                                 cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
926                                 if (cmdentry.u.index < 0) {
927                                         cmdentry.u.index = BLTINCMD;
928                                         argv--;
929                                         argc++;
930                                         break;
931                                 }
932                         } else
933                                 find_command(argv[0], &cmdentry, cmd_flags, path);
934                         /* implement the bltin and command builtins here */
935                         if (cmdentry.cmdtype != CMDBUILTIN)
936                                 break;
937                         if (cmdentry.u.index == BLTINCMD) {
938                                 if (argc == 1)
939                                         break;
940                                 argv++;
941                                 argc--;
942                                 bltinonly = 1;
943                         } else if (cmdentry.u.index == COMMANDCMD) {
944                                 if (argc == 1)
945                                         break;
946                                 if (!strcmp(argv[1], "-p")) {
947                                         if (argc == 2)
948                                                 break;
949                                         if (argv[2][0] == '-') {
950                                                 if (strcmp(argv[2], "--"))
951                                                         break;
952                                                 if (argc == 3)
953                                                         break;
954                                                 argv += 3;
955                                                 argc -= 3;
956                                         } else {
957                                                 argv += 2;
958                                                 argc -= 2;
959                                         }
960                                         path = _PATH_STDPATH;
961                                         clearcmdentry();
962                                         do_clearcmdentry = 1;
963                                 } else if (!strcmp(argv[1], "--")) {
964                                         if (argc == 2)
965                                                 break;
966                                         argv += 2;
967                                         argc -= 2;
968                                 } else if (argv[1][0] == '-')
969                                         break;
970                                 else {
971                                         argv++;
972                                         argc--;
973                                 }
974                                 cmd_flags |= DO_NOFUNC;
975                                 bltinonly = 0;
976                         } else
977                                 break;
978                 }
979                 /*
980                  * Special builtins lose their special properties when
981                  * called via 'command'.
982                  */
983                 if (cmd_flags & DO_NOFUNC)
984                         cmdentry.special = 0;
985         }
986
987         /* Fork off a child process if necessary. */
988         if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
989             && ((flags & EV_EXIT) == 0 || have_traps()))
990          || ((flags & EV_BACKCMD) != 0
991             && (cmdentry.cmdtype != CMDBUILTIN ||
992                  !safe_builtin(cmdentry.u.index, argc, argv)))) {
993                 jp = makejob(cmd, 1);
994                 mode = FORK_FG;
995                 if (flags & EV_BACKCMD) {
996                         mode = FORK_NOJOB;
997                         if (pipe(pip) < 0)
998                                 error("Pipe call failed: %s", strerror(errno));
999                 }
1000                 if (cmdentry.cmdtype == CMDNORMAL &&
1001                     cmd->ncmd.redirect == NULL &&
1002                     varlist.list == NULL &&
1003                     (mode == FORK_FG || mode == FORK_NOJOB) &&
1004                     !disvforkset() && !iflag && !mflag) {
1005                         vforkexecshell(jp, argv, environment(), path,
1006                             cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL);
1007                         goto parent;
1008                 }
1009                 if (forkshell(jp, cmd, mode) != 0)
1010                         goto parent;    /* at end of routine */
1011                 if (flags & EV_BACKCMD) {
1012                         FORCEINTON;
1013                         close(pip[0]);
1014                         if (pip[1] != 1) {
1015                                 dup2(pip[1], 1);
1016                                 close(pip[1]);
1017                         }
1018                         flags &= ~EV_BACKCMD;
1019                 }
1020                 flags |= EV_EXIT;
1021         }
1022
1023         /* This is the child process if a fork occurred. */
1024         /* Execute the command. */
1025         if (cmdentry.cmdtype == CMDFUNCTION) {
1026 #ifdef DEBUG
1027                 trputs("Shell function:  ");  trargs(argv);
1028 #endif
1029                 saveparam = shellparam;
1030                 shellparam.malloc = 0;
1031                 shellparam.reset = 1;
1032                 shellparam.nparam = argc - 1;
1033                 shellparam.p = argv + 1;
1034                 shellparam.optp = NULL;
1035                 shellparam.optnext = NULL;
1036                 INTOFF;
1037                 savelocalvars = localvars;
1038                 localvars = NULL;
1039                 reffunc(cmdentry.u.func);
1040                 savehandler = handler;
1041                 if (setjmp(jmploc.loc)) {
1042                         freeparam(&shellparam);
1043                         shellparam = saveparam;
1044                         popredir();
1045                         unreffunc(cmdentry.u.func);
1046                         poplocalvars();
1047                         localvars = savelocalvars;
1048                         funcnest--;
1049                         handler = savehandler;
1050                         longjmp(handler->loc, 1);
1051                 }
1052                 handler = &jmploc;
1053                 funcnest++;
1054                 redirect(cmd->ncmd.redirect, REDIR_PUSH);
1055                 INTON;
1056                 for (sp = varlist.list ; sp ; sp = sp->next)
1057                         mklocal(sp->text);
1058                 exitstatus = oexitstatus;
1059                 evaltree(getfuncnode(cmdentry.u.func),
1060                     flags & (EV_TESTED | EV_EXIT));
1061                 INTOFF;
1062                 unreffunc(cmdentry.u.func);
1063                 poplocalvars();
1064                 localvars = savelocalvars;
1065                 freeparam(&shellparam);
1066                 shellparam = saveparam;
1067                 handler = savehandler;
1068                 funcnest--;
1069                 popredir();
1070                 INTON;
1071                 if (evalskip == SKIPRETURN) {
1072                         evalskip = 0;
1073                         skipcount = 0;
1074                 }
1075                 if (jp)
1076                         exitshell(exitstatus);
1077         } else if (cmdentry.cmdtype == CMDBUILTIN) {
1078 #ifdef DEBUG
1079                 trputs("builtin command:  ");  trargs(argv);
1080 #endif
1081                 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
1082                 if (flags == EV_BACKCMD) {
1083                         memout.nleft = 0;
1084                         memout.nextc = memout.buf;
1085                         memout.bufsize = 64;
1086                         mode |= REDIR_BACKQ;
1087                 }
1088                 savecmdname = commandname;
1089                 savetopfile = getcurrentfile();
1090                 cmdenviron = varlist.list;
1091                 e = -1;
1092                 savehandler = handler;
1093                 if (setjmp(jmploc.loc)) {
1094                         e = exception;
1095                         if (e == EXINT)
1096                                 exitstatus = SIGINT+128;
1097                         else if (e != EXEXIT)
1098                                 exitstatus = 2;
1099                         goto cmddone;
1100                 }
1101                 handler = &jmploc;
1102                 redirect(cmd->ncmd.redirect, mode);
1103                 outclearerror(out1);
1104                 /*
1105                  * If there is no command word, redirection errors should
1106                  * not be fatal but assignment errors should.
1107                  */
1108                 if (argc == 0)
1109                         cmdentry.special = 1;
1110                 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
1111                 if (argc > 0)
1112                         bltinsetlocale();
1113                 commandname = argv[0];
1114                 argptr = argv + 1;
1115                 nextopt_optptr = NULL;          /* initialize nextopt */
1116                 builtin_flags = flags;
1117                 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
1118                 flushall();
1119                 if (outiserror(out1)) {
1120                         warning("write error on stdout");
1121                         if (exitstatus == 0 || exitstatus == 1)
1122                                 exitstatus = 2;
1123                 }
1124 cmddone:
1125                 if (argc > 0)
1126                         bltinunsetlocale();
1127                 cmdenviron = NULL;
1128                 out1 = &output;
1129                 out2 = &errout;
1130                 freestdout();
1131                 handler = savehandler;
1132                 commandname = savecmdname;
1133                 if (jp)
1134                         exitshell(exitstatus);
1135                 if (flags == EV_BACKCMD) {
1136                         backcmd->buf = memout.buf;
1137                         backcmd->nleft = memout.nextc - memout.buf;
1138                         memout.buf = NULL;
1139                 }
1140                 if (cmdentry.u.index != EXECCMD)
1141                         popredir();
1142                 if (e != -1) {
1143                         if ((e != EXERROR && e != EXEXEC)
1144                             || cmdentry.special)
1145                                 exraise(e);
1146                         popfilesupto(savetopfile);
1147                         if (flags != EV_BACKCMD)
1148                                 FORCEINTON;
1149                 }
1150         } else {
1151 #ifdef DEBUG
1152                 trputs("normal command:  ");  trargs(argv);
1153 #endif
1154                 redirect(cmd->ncmd.redirect, 0);
1155                 for (sp = varlist.list ; sp ; sp = sp->next)
1156                         setvareq(sp->text, VEXPORT|VSTACK);
1157                 envp = environment();
1158                 shellexec(argv, envp, path, cmdentry.u.index);
1159                 /*NOTREACHED*/
1160         }
1161         goto out;
1162
1163 parent: /* parent process gets here (if we forked) */
1164         if (mode == FORK_FG) {  /* argument to fork */
1165                 INTOFF;
1166                 exitstatus = waitforjob(jp, &realstatus);
1167                 INTON;
1168                 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
1169                         evalskip = SKIPBREAK;
1170                         skipcount = loopnest;
1171                 }
1172         } else if (mode == FORK_NOJOB) {
1173                 backcmd->fd = pip[0];
1174                 close(pip[1]);
1175                 backcmd->jp = jp;
1176         }
1177
1178 out:
1179         if (lastarg)
1180                 setvar("_", lastarg, 0);
1181         if (do_clearcmdentry)
1182                 clearcmdentry();
1183 }
1184
1185
1186
1187 /*
1188  * Search for a command.  This is called before we fork so that the
1189  * location of the command will be available in the parent as well as
1190  * the child.  The check for "goodname" is an overly conservative
1191  * check that the name will not be subject to expansion.
1192  */
1193
1194 static void
1195 prehash(union node *n)
1196 {
1197         struct cmdentry entry;
1198
1199         if (n && n->type == NCMD && n->ncmd.args)
1200                 if (goodname(n->ncmd.args->narg.text))
1201                         find_command(n->ncmd.args->narg.text, &entry, 0,
1202                                      pathval());
1203 }
1204
1205
1206
1207 /*
1208  * Builtin commands.  Builtin commands whose functions are closely
1209  * tied to evaluation are implemented here.
1210  */
1211
1212 /*
1213  * No command given, a bltin command with no arguments, or a bltin command
1214  * with an invalid name.
1215  */
1216
1217 int
1218 bltincmd(int argc, char **argv)
1219 {
1220         if (argc > 1) {
1221                 out2fmt_flush("%s: not found\n", argv[1]);
1222                 return 127;
1223         }
1224         /*
1225          * Preserve exitstatus of a previous possible redirection
1226          * as POSIX mandates
1227          */
1228         return exitstatus;
1229 }
1230
1231
1232 /*
1233  * Handle break and continue commands.  Break, continue, and return are
1234  * all handled by setting the evalskip flag.  The evaluation routines
1235  * above all check this flag, and if it is set they start skipping
1236  * commands rather than executing them.  The variable skipcount is
1237  * the number of loops to break/continue, or the number of function
1238  * levels to return.  (The latter is always 1.)  It should probably
1239  * be an error to break out of more loops than exist, but it isn't
1240  * in the standard shell so we don't make it one here.
1241  */
1242
1243 int
1244 breakcmd(int argc, char **argv)
1245 {
1246         long n;
1247         char *end;
1248
1249         if (argc > 1) {
1250                 /* Allow arbitrarily large numbers. */
1251                 n = strtol(argv[1], &end, 10);
1252                 if (!is_digit(argv[1][0]) || *end != '\0')
1253                         error("Illegal number: %s", argv[1]);
1254         } else
1255                 n = 1;
1256         if (n > loopnest)
1257                 n = loopnest;
1258         if (n > 0) {
1259                 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
1260                 skipcount = n;
1261         }
1262         return 0;
1263 }
1264
1265 /*
1266  * The `command' command.
1267  */
1268 int
1269 commandcmd(int argc __unused, char **argv __unused)
1270 {
1271         const char *path;
1272         int ch;
1273         int cmd = -1;
1274
1275         path = bltinlookup("PATH", 1);
1276
1277         while ((ch = nextopt("pvV")) != '\0') {
1278                 switch (ch) {
1279                 case 'p':
1280                         path = _PATH_STDPATH;
1281                         break;
1282                 case 'v':
1283                         cmd = TYPECMD_SMALLV;
1284                         break;
1285                 case 'V':
1286                         cmd = TYPECMD_BIGV;
1287                         break;
1288                 }
1289         }
1290
1291         if (cmd != -1) {
1292                 if (*argptr == NULL || argptr[1] != NULL)
1293                         error("wrong number of arguments");
1294                 return typecmd_impl(2, argptr - 1, cmd, path);
1295         }
1296         if (*argptr != NULL)
1297                 error("commandcmd bad call");
1298
1299         /*
1300          * Do nothing successfully if no command was specified;
1301          * ksh also does this.
1302          */
1303         return 0;
1304 }
1305
1306
1307 /*
1308  * The return command.
1309  */
1310
1311 int
1312 returncmd(int argc, char **argv)
1313 {
1314         int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1315
1316         evalskip = SKIPRETURN;
1317                 skipcount = 1;
1318         return ret;
1319 }
1320
1321
1322 int
1323 falsecmd(int argc __unused, char **argv __unused)
1324 {
1325         return 1;
1326 }
1327
1328
1329 int
1330 truecmd(int argc __unused, char **argv __unused)
1331 {
1332         return 0;
1333 }
1334
1335
1336 int
1337 execcmd(int argc, char **argv)
1338 {
1339         /*
1340          * Because we have historically not supported any options,
1341          * only treat "--" specially.
1342          */
1343         if (argc > 1 && strcmp(argv[1], "--") == 0)
1344                 argc--, argv++;
1345         if (argc > 1) {
1346                 struct strlist *sp;
1347
1348                 iflag = 0;              /* exit on error */
1349                 mflag = 0;
1350                 optschanged();
1351                 for (sp = cmdenviron; sp ; sp = sp->next)
1352                         setvareq(sp->text, VEXPORT|VSTACK);
1353                 shellexec(argv + 1, environment(), pathval(), 0);
1354
1355         }
1356         return 0;
1357 }
1358
1359
1360 int
1361 timescmd(int argc __unused, char **argv __unused)
1362 {
1363         struct rusage ru;
1364         long shumins, shsmins, chumins, chsmins;
1365         double shusecs, shssecs, chusecs, chssecs;
1366
1367         if (getrusage(RUSAGE_SELF, &ru) < 0)
1368                 return 1;
1369         shumins = ru.ru_utime.tv_sec / 60;
1370         shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1371         shsmins = ru.ru_stime.tv_sec / 60;
1372         shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1373         if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1374                 return 1;
1375         chumins = ru.ru_utime.tv_sec / 60;
1376         chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1377         chsmins = ru.ru_stime.tv_sec / 60;
1378         chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1379         out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1380             shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1381         return 0;
1382 }