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