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 arglist *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         int i;
 356         int status;
 357
 358         emptyarglist(&arglist);
 359         for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
 360                 oexitstatus = exitstatus;
 361                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 362         }
 363
 364         loopnest++;
 365         status = 0;
 366         for (i = 0; i < arglist.count; i++) {
 367                 setvar(n->nfor.var, arglist.args[i], 0);
 368                 evaltree(n->nfor.body, flags);
 369                 status = exitstatus;
 370                 if (evalskip) {
 371                         if (evalskip == SKIPCONT && --skipcount <= 0) {
 372                                 evalskip = 0;
 373                                 continue;
 374                         }
 375                         if (evalskip == SKIPBREAK && --skipcount <= 0)
 376                                 evalskip = 0;
 377                         break;
 378                 }
 379         }
 380         loopnest--;
 381         exitstatus = status;
 382 }
 383
 384
 385 /*
 386  * Evaluate a case statement, returning the selected tree.
 387  *
 388  * The exit status needs care to get right.
 389  */
 390
 391 static union node *
 392 evalcase(union node *n)
 393 {
 394         union node *cp;
 395         union node *patp;
 396         struct arglist arglist;
 397
 398         emptyarglist(&arglist);
 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.args[0])) {
 404                                 while (cp->nclist.next &&
 405                                     cp->type == NCLISTFALLTHRU &&
 406                                     cp->nclist.body == NULL)
 407                                         cp = cp->nclist.next;
 408                                 if (cp->nclist.next &&
 409                                     cp->type == NCLISTFALLTHRU)
 410                                         return (cp);
 411                                 if (cp->nclist.body == NULL)
 412                                         exitstatus = 0;
 413                                 return (cp->nclist.body);
 414                         }
 415                 }
 416         }
 417         exitstatus = 0;
 418         return (NULL);
 419 }
 420
 421
 422
 423 /*
 424  * Kick off a subshell to evaluate a tree.
 425  */
 426
 427 static void
 428 evalsubshell(union node *n, int flags)
 429 {
 430         struct job *jp;
 431         int backgnd = (n->type == NBACKGND);
 432
 433         oexitstatus = exitstatus;
 434         expredir(n->nredir.redirect);
 435         if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
 436                         forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
 437                 if (backgnd)
 438                         flags &=~ EV_TESTED;
 439                 redirect(n->nredir.redirect, 0);
 440                 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
 441         } else if (! backgnd) {
 442                 INTOFF;
 443                 exitstatus = waitforjob(jp, (int *)NULL);
 444                 INTON;
 445         } else
 446                 exitstatus = 0;
 447 }
 448
 449
 450 /*
 451  * Evaluate a redirected compound command.
 452  */
 453
 454 static void
 455 evalredir(union node *n, int flags)
 456 {
 457         struct jmploc jmploc;
 458         struct jmploc *savehandler;
 459         volatile int in_redirect = 1;
 460
 461         oexitstatus = exitstatus;
 462         expredir(n->nredir.redirect);
 463         savehandler = handler;
 464         if (setjmp(jmploc.loc)) {
 465                 int e;
 466
 467                 handler = savehandler;
 468                 e = exception;
 469                 popredir();
 470                 if (e == EXERROR || e == EXEXEC) {
 471                         if (in_redirect) {
 472                                 exitstatus = 2;
 473                                 return;
 474                         }
 475                 }
 476                 longjmp(handler->loc, 1);
 477         } else {
 478                 INTOFF;
 479                 handler = &jmploc;
 480                 redirect(n->nredir.redirect, REDIR_PUSH);
 481                 in_redirect = 0;
 482                 INTON;
 483                 evaltree(n->nredir.n, flags);
 484         }
 485         INTOFF;
 486         handler = savehandler;
 487         popredir();
 488         INTON;
 489 }
 490
 491
 492 static void
 493 exphere(union node *redir, struct arglist *fn)
 494 {
 495         struct jmploc jmploc;
 496         struct jmploc *savehandler;
 497         struct localvar *savelocalvars;
 498         int need_longjmp = 0;
 499
 500         redir->nhere.expdoc = "";
 501         savelocalvars = localvars;
 502         localvars = NULL;
 503         forcelocal++;
 504         savehandler = handler;
 505         if (setjmp(jmploc.loc))
 506                 need_longjmp = exception != EXERROR && exception != EXEXEC;
 507         else {
 508                 handler = &jmploc;
 509                 expandarg(redir->nhere.doc, fn, 0);
 510                 redir->nhere.expdoc = fn->args[0];
 511                 INTOFF;
 512         }
 513         handler = savehandler;
 514         forcelocal--;
 515         poplocalvars();
 516         localvars = savelocalvars;
 517         if (need_longjmp)
 518                 longjmp(handler->loc, 1);
 519         INTON;
 520 }
 521
 522
 523 /*
 524  * Compute the names of the files in a redirection list.
 525  */
 526
 527 static void
 528 expredir(union node *n)
 529 {
 530         union node *redir;
 531
 532         for (redir = n ; redir ; redir = redir->nfile.next) {
 533                 struct arglist fn;
 534                 emptyarglist(&fn);
 535                 switch (redir->type) {
 536                 case NFROM:
 537                 case NTO:
 538                 case NFROMTO:
 539                 case NAPPEND:
 540                 case NCLOBBER:
 541                         expandarg(redir->nfile.fname, &fn, EXP_TILDE);
 542                         redir->nfile.expfname = fn.args[0];
 543                         break;
 544                 case NFROMFD:
 545                 case NTOFD:
 546                         if (redir->ndup.vname) {
 547                                 expandarg(redir->ndup.vname, &fn, EXP_TILDE);
 548                                 fixredir(redir, fn.args[0], 1);
 549                         }
 550                         break;
 551                 case NXHERE:
 552                         exphere(redir, &fn);
 553                         break;
 554                 }
 555         }
 556 }
 557
 558
 559
 560 /*
 561  * Evaluate a pipeline.  All the processes in the pipeline are children
 562  * of the process creating the pipeline.  (This differs from some versions
 563  * of the shell, which make the last process in a pipeline the parent
 564  * of all the rest.)
 565  */
 566
 567 static void
 568 evalpipe(union node *n)
 569 {
 570         struct job *jp;
 571         struct nodelist *lp;
 572         int pipelen;
 573         int prevfd;
 574         int pip[2];
 575
 576         TRACE(("evalpipe(%p) called\n", (void *)n));
 577         pipelen = 0;
 578         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
 579                 pipelen++;
 580         INTOFF;
 581         jp = makejob(n, pipelen);
 582         prevfd = -1;
 583         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
 584                 prehash(lp->n);
 585                 pip[1] = -1;
 586                 if (lp->next) {
 587                         if (pipe(pip) < 0) {
 588                                 if (prevfd >= 0)
 589                                         close(prevfd);
 590                                 error("Pipe call failed: %s", strerror(errno));
 591                         }
 592                 }
 593                 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
 594                         INTON;
 595                         if (prevfd > 0) {
 596                                 dup2(prevfd, 0);
 597                                 close(prevfd);
 598                         }
 599                         if (pip[1] >= 0) {
 600                                 if (!(prevfd >= 0 && pip[0] == 0))
 601                                         close(pip[0]);
 602                                 if (pip[1] != 1) {
 603                                         dup2(pip[1], 1);
 604                                         close(pip[1]);
 605                                 }
 606                         }
 607                         evaltree(lp->n, EV_EXIT);
 608                 }
 609                 if (prevfd >= 0)
 610                         close(prevfd);
 611                 prevfd = pip[0];
 612                 if (pip[1] != -1)
 613                         close(pip[1]);
 614         }
 615         INTON;
 616         if (n->npipe.backgnd == 0) {
 617                 INTOFF;
 618                 exitstatus = waitforjob(jp, (int *)NULL);
 619                 TRACE(("evalpipe:  job done exit status %d\n", exitstatus));
 620                 INTON;
 621         } else
 622                 exitstatus = 0;
 623 }
 624
 625
 626
 627 static int
 628 is_valid_fast_cmdsubst(union node *n)
 629 {
 630
 631         return (n->type == NCMD);
 632 }
 633
 634 /*
 635  * Execute a command inside back quotes.  If it's a builtin command, we
 636  * want to save its output in a block obtained from malloc.  Otherwise
 637  * we fork off a subprocess and get the output of the command via a pipe.
 638  * Should be called with interrupts off.
 639  */
 640
 641 void
 642 evalbackcmd(union node *n, struct backcmd *result)
 643 {
 644         int pip[2];
 645         struct job *jp;
 646         struct stackmark smark;
 647         struct jmploc jmploc;
 648         struct jmploc *savehandler;
 649         struct localvar *savelocalvars;
 650
 651         result->fd = -1;
 652         result->buf = NULL;
 653         result->nleft = 0;
 654         result->jp = NULL;
 655         if (n == NULL) {
 656                 exitstatus = 0;
 657                 return;
 658         }
 659         setstackmark(&smark);
 660         exitstatus = oexitstatus;
 661         if (is_valid_fast_cmdsubst(n)) {
 662                 savelocalvars = localvars;
 663                 localvars = NULL;
 664                 forcelocal++;
 665                 savehandler = handler;
 666                 if (setjmp(jmploc.loc)) {
 667                         if (exception == EXERROR || exception == EXEXEC)
 668                                 exitstatus = 2;
 669                         else if (exception != 0) {
 670                                 handler = savehandler;
 671                                 forcelocal--;
 672                                 poplocalvars();
 673                                 localvars = savelocalvars;
 674                                 longjmp(handler->loc, 1);
 675                         }
 676                 } else {
 677                         handler = &jmploc;
 678                         evalcommand(n, EV_BACKCMD, result);
 679                 }
 680                 handler = savehandler;
 681                 forcelocal--;
 682                 poplocalvars();
 683                 localvars = savelocalvars;
 684         } else {
 685                 if (pipe(pip) < 0)
 686                         error("Pipe call failed: %s", strerror(errno));
 687                 jp = makejob(n, 1);
 688                 if (forkshell(jp, n, FORK_NOJOB) == 0) {
 689                         FORCEINTON;
 690                         close(pip[0]);
 691                         if (pip[1] != 1) {
 692                                 dup2(pip[1], 1);
 693                                 close(pip[1]);
 694                         }
 695                         evaltree(n, EV_EXIT);
 696                 }
 697                 close(pip[1]);
 698                 result->fd = pip[0];
 699                 result->jp = jp;
 700         }
 701         popstackmark(&smark);
 702         TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
 703                 result->fd, result->buf, result->nleft, result->jp));
 704 }
 705
 706 static int
 707 mustexpandto(const char *argtext, const char *mask)
 708 {
 709         for (;;) {
 710                 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) {
 711                         argtext++;
 712                         continue;
 713                 }
 714                 if (*argtext == CTLESC)
 715                         argtext++;
 716                 else if (BASESYNTAX[(int)*argtext] == CCTL)
 717                         return (0);
 718                 if (*argtext != *mask)
 719                         return (0);
 720                 if (*argtext == '\0')
 721                         return (1);
 722                 argtext++;
 723                 mask++;
 724         }
 725 }
 726
 727 static int
 728 isdeclarationcmd(struct narg *arg)
 729 {
 730         int have_command = 0;
 731
 732         if (arg == NULL)
 733                 return (0);
 734         while (mustexpandto(arg->text, "command")) {
 735                 have_command = 1;
 736                 arg = &arg->next->narg;
 737                 if (arg == NULL)
 738                         return (0);
 739                 /*
 740                  * To also allow "command -p" and "command --" as part of
 741                  * a declaration command, add code here.
 742                  * We do not do this, as ksh does not do it either and it
 743                  * is not required by POSIX.
 744                  */
 745         }
 746         return (mustexpandto(arg->text, "export") ||
 747             mustexpandto(arg->text, "readonly") ||
 748             (mustexpandto(arg->text, "local") &&
 749                 (have_command || !isfunc("local"))));
 750 }
 751
 752 static void
 753 xtracecommand(struct arglist *varlist, struct arglist *arglist)
 754 {
 755         char sep = 0;
 756         const char *text, *p, *ps4;
 757         int i;
 758
 759         ps4 = expandstr(ps4val());
 760         out2str(ps4 != NULL ? ps4 : ps4val());
 761         for (i = 0; i < varlist->count; i++) {
 762                 text = varlist->args[i];
 763                 if (sep != 0)
 764                         out2c(' ');
 765                 p = strchr(text, '=');
 766                 if (p != NULL) {
 767                         p++;
 768                         outbin(text, p - text, out2);
 769                         out2qstr(p);
 770                 } else
 771                         out2qstr(text);
 772                 sep = ' ';
 773         }
 774         for (i = 0; i < arglist->count; i++) {
 775                 text = arglist->args[i];
 776                 if (sep != 0)
 777                         out2c(' ');
 778                 out2qstr(text);
 779                 sep = ' ';
 780         }
 781         out2c('\n');
 782         flushout(&errout);
 783 }
 784
 785 /*
 786  * Check if a builtin can safely be executed in the same process,
 787  * even though it should be in a subshell (command substitution).
 788  * Note that jobid, jobs, times and trap can show information not
 789  * available in a child process; this is deliberate.
 790  * The arguments should already have been expanded.
 791  */
 792 static int
 793 safe_builtin(int idx, int argc, char **argv)
 794 {
 795         if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD ||
 796             idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD ||
 797             idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD ||
 798             idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD ||
 799             idx == TYPECMD)
 800                 return (1);
 801         if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD ||
 802             idx == UMASKCMD)
 803                 return (argc <= 1 || (argc == 2 && argv[1][0] == '-'));
 804         if (idx == SETCMD)
 805                 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' ||
 806                     argv[1][0] == '+') && argv[1][1] == 'o' &&
 807                     argv[1][2] == '\0'));
 808         return (0);
 809 }
 810
 811 /*
 812  * Execute a simple command.
 813  * Note: This may or may not return if (flags & EV_EXIT).
 814  */
 815
 816 static void
 817 evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
 818 {
 819         union node *argp;
 820         struct arglist arglist;
 821         struct arglist varlist;
 822         char **argv;
 823         int argc;
 824         char **envp;
 825         int varflag;
 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         int i;
 842
 843         /* First expand the arguments. */
 844         TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
 845         emptyarglist(&arglist);
 846         emptyarglist(&varlist);
 847         varflag = 1;
 848         jp = NULL;
 849         do_clearcmdentry = 0;
 850         oexitstatus = exitstatus;
 851         exitstatus = 0;
 852         for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
 853                 if (varflag && isassignment(argp->narg.text)) {
 854                         expandarg(argp, varflag == 1 ? &varlist : &arglist,
 855                             EXP_VARTILDE);
 856                         continue;
 857                 } else if (varflag == 1)
 858                         varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
 859                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 860         }
 861         expredir(cmd->ncmd.redirect);
 862         argc = arglist.count;
 863         /* Add one slot at the beginning for tryexec(). */
 864         argv = stalloc(sizeof (char *) * (argc + 2));
 865         argv++;
 866
 867         memcpy(argv, arglist.args, sizeof(*argv) * argc);
 868         argv[argc] = NULL;
 869         lastarg = NULL;
 870         if (iflag && funcnest == 0 && argc > 0)
 871                 lastarg = argv[argc - 1];
 872
 873         /* Print the command if xflag is set. */
 874         if (xflag)
 875                 xtracecommand(&varlist, &arglist);
 876
 877         /* Now locate the command. */
 878         if (argc == 0) {
 879                 /* Variable assignment(s) without command */
 880                 cmdentry.cmdtype = CMDBUILTIN;
 881                 cmdentry.u.index = BLTINCMD;
 882                 cmdentry.special = 0;
 883         } else {
 884                 static const char PATH[] = "PATH=";
 885                 int cmd_flags = 0, bltinonly = 0;
 886
 887                 /*
 888                  * Modify the command lookup path, if a PATH= assignment
 889                  * is present
 890                  */
 891                 for (i = 0; i < varlist.count; i++)
 892                         if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) {
 893                                 path = varlist.args[i] + sizeof(PATH) - 1;
 894                                 /*
 895                                  * On `PATH=... command`, we need to make
 896                                  * sure that the command isn't using the
 897                                  * non-updated hash table of the outer PATH
 898                                  * setting and we need to make sure that
 899                                  * the hash table isn't filled with items
 900                                  * from the temporary setting.
 901                                  *
 902                                  * It would be better to forbit using and
 903                                  * updating the table while this command
 904                                  * runs, by the command finding mechanism
 905                                  * is heavily integrated with hash handling,
 906                                  * so we just delete the hash before and after
 907                                  * the command runs. Partly deleting like
 908                                  * changepatch() does doesn't seem worth the
 909                                  * bookinging effort, since most such runs add
 910                                  * directories in front of the new PATH.
 911                                  */
 912                                 clearcmdentry();
 913                                 do_clearcmdentry = 1;
 914                         }
 915
 916                 for (;;) {
 917                         if (bltinonly) {
 918                                 cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
 919                                 if (cmdentry.u.index < 0) {
 920                                         cmdentry.u.index = BLTINCMD;
 921                                         argv--;
 922                                         argc++;
 923                                         break;
 924                                 }
 925                         } else
 926                                 find_command(argv[0], &cmdentry, cmd_flags, path);
 927                         /* implement the bltin and command builtins here */
 928                         if (cmdentry.cmdtype != CMDBUILTIN)
 929                                 break;
 930                         if (cmdentry.u.index == BLTINCMD) {
 931                                 if (argc == 1)
 932                                         break;
 933                                 argv++;
 934                                 argc--;
 935                                 bltinonly = 1;
 936                         } else if (cmdentry.u.index == COMMANDCMD) {
 937                                 if (argc == 1)
 938                                         break;
 939                                 if (!strcmp(argv[1], "-p")) {
 940                                         if (argc == 2)
 941                                                 break;
 942                                         if (argv[2][0] == '-') {
 943                                                 if (strcmp(argv[2], "--"))
 944                                                         break;
 945                                                 if (argc == 3)
 946                                                         break;
 947                                                 argv += 3;
 948                                                 argc -= 3;
 949                                         } else {
 950                                                 argv += 2;
 951                                                 argc -= 2;
 952                                         }
 953                                         path = _PATH_STDPATH;
 954                                         clearcmdentry();
 955                                         do_clearcmdentry = 1;
 956                                 } else if (!strcmp(argv[1], "--")) {
 957                                         if (argc == 2)
 958                                                 break;
 959                                         argv += 2;
 960                                         argc -= 2;
 961                                 } else if (argv[1][0] == '-')
 962                                         break;
 963                                 else {
 964                                         argv++;
 965                                         argc--;
 966                                 }
 967                                 cmd_flags |= DO_NOFUNC;
 968                                 bltinonly = 0;
 969                         } else
 970                                 break;
 971                 }
 972                 /*
 973                  * Special builtins lose their special properties when
 974                  * called via 'command'.
 975                  */
 976                 if (cmd_flags & DO_NOFUNC)
 977                         cmdentry.special = 0;
 978         }
 979
 980         /* Fork off a child process if necessary. */
 981         if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
 982             && ((flags & EV_EXIT) == 0 || have_traps()))
 983          || ((flags & EV_BACKCMD) != 0
 984             && (cmdentry.cmdtype != CMDBUILTIN ||
 985                  !safe_builtin(cmdentry.u.index, argc, argv)))) {
 986                 jp = makejob(cmd, 1);
 987                 mode = FORK_FG;
 988                 if (flags & EV_BACKCMD) {
 989                         mode = FORK_NOJOB;
 990                         if (pipe(pip) < 0)
 991                                 error("Pipe call failed: %s", strerror(errno));
 992                 }
 993                 if (cmdentry.cmdtype == CMDNORMAL &&
 994                     cmd->ncmd.redirect == NULL &&
 995                     varlist.count == 0 &&
 996                     (mode == FORK_FG || mode == FORK_NOJOB) &&
 997                     !disvforkset() && !iflag && !mflag) {
 998                         vforkexecshell(jp, argv, environment(), path,
 999                             cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL);
1000                         goto parent;
1001                 }
1002                 if (forkshell(jp, cmd, mode) != 0)
1003                         goto parent;    /* at end of routine */
1004                 if (flags & EV_BACKCMD) {
1005                         FORCEINTON;
1006                         close(pip[0]);
1007                         if (pip[1] != 1) {
1008                                 dup2(pip[1], 1);
1009                                 close(pip[1]);
1010                         }
1011                         flags &= ~EV_BACKCMD;
1012                 }
1013                 flags |= EV_EXIT;
1014         }
1015
1016         /* This is the child process if a fork occurred. */
1017         /* Execute the command. */
1018         if (cmdentry.cmdtype == CMDFUNCTION) {
1019 #ifdef DEBUG
1020                 trputs("Shell function:  ");  trargs(argv);
1021 #endif
1022                 saveparam = shellparam;
1023                 shellparam.malloc = 0;
1024                 shellparam.reset = 1;
1025                 shellparam.nparam = argc - 1;
1026                 shellparam.p = argv + 1;
1027                 shellparam.optp = NULL;
1028                 shellparam.optnext = NULL;
1029                 INTOFF;
1030                 savelocalvars = localvars;
1031                 localvars = NULL;
1032                 reffunc(cmdentry.u.func);
1033                 savehandler = handler;
1034                 if (setjmp(jmploc.loc)) {
1035                         freeparam(&shellparam);
1036                         shellparam = saveparam;
1037                         popredir();
1038                         unreffunc(cmdentry.u.func);
1039                         poplocalvars();
1040                         localvars = savelocalvars;
1041                         funcnest--;
1042                         handler = savehandler;
1043                         longjmp(handler->loc, 1);
1044                 }
1045                 handler = &jmploc;
1046                 funcnest++;
1047                 redirect(cmd->ncmd.redirect, REDIR_PUSH);
1048                 INTON;
1049                 for (i = 0; i < varlist.count; i++)
1050                         mklocal(varlist.args[i]);
1051                 exitstatus = oexitstatus;
1052                 evaltree(getfuncnode(cmdentry.u.func),
1053                     flags & (EV_TESTED | EV_EXIT));
1054                 INTOFF;
1055                 unreffunc(cmdentry.u.func);
1056                 poplocalvars();
1057                 localvars = savelocalvars;
1058                 freeparam(&shellparam);
1059                 shellparam = saveparam;
1060                 handler = savehandler;
1061                 funcnest--;
1062                 popredir();
1063                 INTON;
1064                 if (evalskip == SKIPRETURN) {
1065                         evalskip = 0;
1066                         skipcount = 0;
1067                 }
1068                 if (jp)
1069                         exitshell(exitstatus);
1070         } else if (cmdentry.cmdtype == CMDBUILTIN) {
1071 #ifdef DEBUG
1072                 trputs("builtin command:  ");  trargs(argv);
1073 #endif
1074                 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
1075                 if (flags == EV_BACKCMD) {
1076                         memout.nleft = 0;
1077                         memout.nextc = memout.buf;
1078                         memout.bufsize = 64;
1079                         mode |= REDIR_BACKQ;
1080                 }
1081                 savecmdname = commandname;
1082                 savetopfile = getcurrentfile();
1083                 cmdenviron = &varlist;
1084                 e = -1;
1085                 savehandler = handler;
1086                 if (setjmp(jmploc.loc)) {
1087                         e = exception;
1088                         if (e == EXINT)
1089                                 exitstatus = SIGINT+128;
1090                         else if (e != EXEXIT)
1091                                 exitstatus = 2;
1092                         goto cmddone;
1093                 }
1094                 handler = &jmploc;
1095                 redirect(cmd->ncmd.redirect, mode);
1096                 outclearerror(out1);
1097                 /*
1098                  * If there is no command word, redirection errors should
1099                  * not be fatal but assignment errors should.
1100                  */
1101                 if (argc == 0)
1102                         cmdentry.special = 1;
1103                 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
1104                 if (argc > 0)
1105                         bltinsetlocale();
1106                 commandname = argv[0];
1107                 argptr = argv + 1;
1108                 nextopt_optptr = NULL;          /* initialize nextopt */
1109                 builtin_flags = flags;
1110                 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
1111                 flushall();
1112                 if (outiserror(out1)) {
1113                         warning("write error on stdout");
1114                         if (exitstatus == 0 || exitstatus == 1)
1115                                 exitstatus = 2;
1116                 }
1117 cmddone:
1118                 if (argc > 0)
1119                         bltinunsetlocale();
1120                 cmdenviron = NULL;
1121                 out1 = &output;
1122                 out2 = &errout;
1123                 freestdout();
1124                 handler = savehandler;
1125                 commandname = savecmdname;
1126                 if (jp)
1127                         exitshell(exitstatus);
1128                 if (flags == EV_BACKCMD) {
1129                         backcmd->buf = memout.buf;
1130                         backcmd->nleft = memout.nextc - memout.buf;
1131                         memout.buf = NULL;
1132                 }
1133                 if (cmdentry.u.index != EXECCMD)
1134                         popredir();
1135                 if (e != -1) {
1136                         if ((e != EXERROR && e != EXEXEC)
1137                             || cmdentry.special)
1138                                 exraise(e);
1139                         popfilesupto(savetopfile);
1140                         if (flags != EV_BACKCMD)
1141                                 FORCEINTON;
1142                 }
1143         } else {
1144 #ifdef DEBUG
1145                 trputs("normal command:  ");  trargs(argv);
1146 #endif
1147                 redirect(cmd->ncmd.redirect, 0);
1148                 for (i = 0; i < varlist.count; i++)
1149                         setvareq(varlist.args[i], VEXPORT|VSTACK);
1150                 envp = environment();
1151                 shellexec(argv, envp, path, cmdentry.u.index);
1152                 /*NOTREACHED*/
1153         }
1154         goto out;
1155
1156 parent: /* parent process gets here (if we forked) */
1157         if (mode == FORK_FG) {  /* argument to fork */
1158                 INTOFF;
1159                 exitstatus = waitforjob(jp, &realstatus);
1160                 INTON;
1161                 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
1162                         evalskip = SKIPBREAK;
1163                         skipcount = loopnest;
1164                 }
1165         } else if (mode == FORK_NOJOB) {
1166                 backcmd->fd = pip[0];
1167                 close(pip[1]);
1168                 backcmd->jp = jp;
1169         }
1170
1171 out:
1172         if (lastarg)
1173                 setvar("_", lastarg, 0);
1174         if (do_clearcmdentry)
1175                 clearcmdentry();
1176 }
1177
1178
1179
1180 /*
1181  * Search for a command.  This is called before we fork so that the
1182  * location of the command will be available in the parent as well as
1183  * the child.  The check for "goodname" is an overly conservative
1184  * check that the name will not be subject to expansion.
1185  */
1186
1187 static void
1188 prehash(union node *n)
1189 {
1190         struct cmdentry entry;
1191
1192         if (n && n->type == NCMD && n->ncmd.args)
1193                 if (goodname(n->ncmd.args->narg.text))
1194                         find_command(n->ncmd.args->narg.text, &entry, 0,
1195                                      pathval());
1196 }
1197
1198
1199
1200 /*
1201  * Builtin commands.  Builtin commands whose functions are closely
1202  * tied to evaluation are implemented here.
1203  */
1204
1205 /*
1206  * No command given, a bltin command with no arguments, or a bltin command
1207  * with an invalid name.
1208  */
1209
1210 int
1211 bltincmd(int argc, char **argv)
1212 {
1213         if (argc > 1) {
1214                 out2fmt_flush("%s: not found\n", argv[1]);
1215                 return 127;
1216         }
1217         /*
1218          * Preserve exitstatus of a previous possible redirection
1219          * as POSIX mandates
1220          */
1221         return exitstatus;
1222 }
1223
1224
1225 /*
1226  * Handle break and continue commands.  Break, continue, and return are
1227  * all handled by setting the evalskip flag.  The evaluation routines
1228  * above all check this flag, and if it is set they start skipping
1229  * commands rather than executing them.  The variable skipcount is
1230  * the number of loops to break/continue, or the number of function
1231  * levels to return.  (The latter is always 1.)  It should probably
1232  * be an error to break out of more loops than exist, but it isn't
1233  * in the standard shell so we don't make it one here.
1234  */
1235
1236 int
1237 breakcmd(int argc, char **argv)
1238 {
1239         long n;
1240         char *end;
1241
1242         if (argc > 1) {
1243                 /* Allow arbitrarily large numbers. */
1244                 n = strtol(argv[1], &end, 10);
1245                 if (!is_digit(argv[1][0]) || *end != '\0')
1246                         error("Illegal number: %s", argv[1]);
1247         } else
1248                 n = 1;
1249         if (n > loopnest)
1250                 n = loopnest;
1251         if (n > 0) {
1252                 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
1253                 skipcount = n;
1254         }
1255         return 0;
1256 }
1257
1258 /*
1259  * The `command' command.
1260  */
1261 int
1262 commandcmd(int argc __unused, char **argv __unused)
1263 {
1264         const char *path;
1265         int ch;
1266         int cmd = -1;
1267
1268         path = bltinlookup("PATH", 1);
1269
1270         while ((ch = nextopt("pvV")) != '\0') {
1271                 switch (ch) {
1272                 case 'p':
1273                         path = _PATH_STDPATH;
1274                         break;
1275                 case 'v':
1276                         cmd = TYPECMD_SMALLV;
1277                         break;
1278                 case 'V':
1279                         cmd = TYPECMD_BIGV;
1280                         break;
1281                 }
1282         }
1283
1284         if (cmd != -1) {
1285                 if (*argptr == NULL || argptr[1] != NULL)
1286                         error("wrong number of arguments");
1287                 return typecmd_impl(2, argptr - 1, cmd, path);
1288         }
1289         if (*argptr != NULL)
1290                 error("commandcmd bad call");
1291
1292         /*
1293          * Do nothing successfully if no command was specified;
1294          * ksh also does this.
1295          */
1296         return 0;
1297 }
1298
1299
1300 /*
1301  * The return command.
1302  */
1303
1304 int
1305 returncmd(int argc, char **argv)
1306 {
1307         int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1308
1309         evalskip = SKIPRETURN;
1310         skipcount = 1;
1311         return ret;
1312 }
1313
1314
1315 int
1316 falsecmd(int argc __unused, char **argv __unused)
1317 {
1318         return 1;
1319 }
1320
1321
1322 int
1323 truecmd(int argc __unused, char **argv __unused)
1324 {
1325         return 0;
1326 }
1327
1328
1329 int
1330 execcmd(int argc, char **argv)
1331 {
1332         int i;
1333
1334         /*
1335          * Because we have historically not supported any options,
1336          * only treat "--" specially.
1337          */
1338         if (argc > 1 && strcmp(argv[1], "--") == 0)
1339                 argc--, argv++;
1340         if (argc > 1) {
1341                 iflag = 0;              /* exit on error */
1342                 mflag = 0;
1343                 optschanged();
1344                 for (i = 0; i < cmdenviron->count; i++)
1345                         setvareq(cmdenviron->args[i], VEXPORT|VSTACK);
1346                 shellexec(argv + 1, environment(), pathval(), 0);
1347
1348         }
1349         return 0;
1350 }
1351
1352
1353 int
1354 timescmd(int argc __unused, char **argv __unused)
1355 {
1356         struct rusage ru;
1357         long shumins, shsmins, chumins, chsmins;
1358         double shusecs, shssecs, chusecs, chssecs;
1359
1360         if (getrusage(RUSAGE_SELF, &ru) < 0)
1361                 return 1;
1362         shumins = ru.ru_utime.tv_sec / 60;
1363         shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1364         shsmins = ru.ru_stime.tv_sec / 60;
1365         shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1366         if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1367                 return 1;
1368         chumins = ru.ru_utime.tv_sec / 60;
1369         chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1370         chsmins = ru.ru_stime.tv_sec / 60;
1371         chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1372         out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1373             shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1374         return 0;
1375 }