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 MKINIT int evalskip;            /* set if we are skipping commands */
  78 STATIC 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 void evalcase(union node *, int);
  93 STATIC void evalsubshell(union node *, int);
  94 STATIC void expredir(union node *);
  95 STATIC void evalpipe(union node *);
  96 STATIC void evalcommand(union node *, int, struct backcmd *);
  97 STATIC void prehash(union node *);
  98
  99
 100 /*
 101  * Called to reset things after an exception.
 102  */
 103
 104 #ifdef mkinit
 105 INCLUDE "eval.h"
 106
 107 RESET {
 108         evalskip = 0;
 109         loopnest = 0;
 110         funcnest = 0;
 111 }
 112
 113 SHELLPROC {
 114         exitstatus = 0;
 115 }
 116 #endif
 117
 118
 119
 120 /*
 121  * The eval command.
 122  */
 123
 124 int
 125 evalcmd(int argc, char **argv)
 126 {
 127         char *p;
 128         char *concat;
 129         char **ap;
 130
 131         if (argc > 1) {
 132                 p = argv[1];
 133                 if (argc > 2) {
 134                         STARTSTACKSTR(concat);
 135                         ap = argv + 2;
 136                         for (;;) {
 137                                 while (*p)
 138                                         STPUTC(*p++, concat);
 139                                 if ((p = *ap++) == NULL)
 140                                         break;
 141                                 STPUTC(' ', concat);
 142                         }
 143                         STPUTC('\0', concat);
 144                         p = grabstackstr(concat);
 145                 }
 146                 evalstring(p, builtin_flags & EV_TESTED);
 147         }
 148         return exitstatus;
 149 }
 150
 151
 152 /*
 153  * Execute a command or commands contained in a string.
 154  */
 155
 156 void
 157 evalstring(char *s, int flags)
 158 {
 159         union node *n;
 160         struct stackmark smark;
 161         int flags_exit;
 162
 163         flags_exit = flags & EV_EXIT;
 164         flags &= ~EV_EXIT;
 165         setstackmark(&smark);
 166         setinputstring(s, 1);
 167         while ((n = parsecmd(0)) != NEOF) {
 168                 if (n != NULL) {
 169                         if (flags_exit && preadateof())
 170                                 evaltree(n, flags | EV_EXIT);
 171                         else
 172                                 evaltree(n, flags);
 173                 }
 174                 popstackmark(&smark);
 175         }
 176         popfile();
 177         popstackmark(&smark);
 178         if (flags_exit)
 179                 exitshell(exitstatus);
 180 }
 181
 182
 183 /*
 184  * Evaluate a parse tree.  The value is left in the global variable
 185  * exitstatus.
 186  */
 187
 188 void
 189 evaltree(union node *n, int flags)
 190 {
 191         int do_etest;
 192
 193         do_etest = 0;
 194         if (n == NULL) {
 195                 TRACE(("evaltree(NULL) called\n"));
 196                 exitstatus = 0;
 197                 goto out;
 198         }
 199 #ifndef NO_HISTORY
 200         displayhist = 1;        /* show history substitutions done with fc */
 201 #endif
 202         TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
 203         switch (n->type) {
 204         case NSEMI:
 205                 evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
 206                 if (evalskip)
 207                         goto out;
 208                 evaltree(n->nbinary.ch2, flags);
 209                 break;
 210         case NAND:
 211                 evaltree(n->nbinary.ch1, EV_TESTED);
 212                 if (evalskip || exitstatus != 0) {
 213                         goto out;
 214                 }
 215                 evaltree(n->nbinary.ch2, flags);
 216                 break;
 217         case NOR:
 218                 evaltree(n->nbinary.ch1, EV_TESTED);
 219                 if (evalskip || exitstatus == 0)
 220                         goto out;
 221                 evaltree(n->nbinary.ch2, flags);
 222                 break;
 223         case NREDIR:
 224                 expredir(n->nredir.redirect);
 225                 redirect(n->nredir.redirect, REDIR_PUSH);
 226                 evaltree(n->nredir.n, flags);
 227                 popredir();
 228                 break;
 229         case NSUBSHELL:
 230                 evalsubshell(n, flags);
 231                 do_etest = !(flags & EV_TESTED);
 232                 break;
 233         case NBACKGND:
 234                 evalsubshell(n, flags);
 235                 break;
 236         case NIF: {
 237                 evaltree(n->nif.test, EV_TESTED);
 238                 if (evalskip)
 239                         goto out;
 240                 if (exitstatus == 0)
 241                         evaltree(n->nif.ifpart, flags);
 242                 else if (n->nif.elsepart)
 243                         evaltree(n->nif.elsepart, flags);
 244                 else
 245                         exitstatus = 0;
 246                 break;
 247         }
 248         case NWHILE:
 249         case NUNTIL:
 250                 evalloop(n, flags & ~EV_EXIT);
 251                 break;
 252         case NFOR:
 253                 evalfor(n, flags & ~EV_EXIT);
 254                 break;
 255         case NCASE:
 256                 evalcase(n, flags);
 257                 break;
 258         case NDEFUN:
 259                 defun(n->narg.text, n->narg.next);
 260                 exitstatus = 0;
 261                 break;
 262         case NNOT:
 263                 evaltree(n->nnot.com, EV_TESTED);
 264                 exitstatus = !exitstatus;
 265                 break;
 266
 267         case NPIPE:
 268                 evalpipe(n);
 269                 do_etest = !(flags & EV_TESTED);
 270                 break;
 271         case NCMD:
 272                 evalcommand(n, flags, (struct backcmd *)NULL);
 273                 do_etest = !(flags & EV_TESTED);
 274                 break;
 275         default:
 276                 out1fmt("Node type = %d\n", n->type);
 277                 flushout(&output);
 278                 break;
 279         }
 280 out:
 281         if (pendingsigs)
 282                 dotrap();
 283         if ((flags & EV_EXIT) || (eflag && exitstatus != 0 && do_etest))
 284                 exitshell(exitstatus);
 285 }
 286
 287
 288 STATIC void
 289 evalloop(union node *n, int flags)
 290 {
 291         int status;
 292
 293         loopnest++;
 294         status = 0;
 295         for (;;) {
 296                 evaltree(n->nbinary.ch1, EV_TESTED);
 297                 if (evalskip) {
 298 skipping:         if (evalskip == SKIPCONT && --skipcount <= 0) {
 299                                 evalskip = 0;
 300                                 continue;
 301                         }
 302                         if (evalskip == SKIPBREAK && --skipcount <= 0)
 303                                 evalskip = 0;
 304                         break;
 305                 }
 306                 if (n->type == NWHILE) {
 307                         if (exitstatus != 0)
 308                                 break;
 309                 } else {
 310                         if (exitstatus == 0)
 311                                 break;
 312                 }
 313                 evaltree(n->nbinary.ch2, flags);
 314                 status = exitstatus;
 315                 if (evalskip)
 316                         goto skipping;
 317         }
 318         loopnest--;
 319         exitstatus = status;
 320 }
 321
 322
 323
 324 STATIC void
 325 evalfor(union node *n, int flags)
 326 {
 327         struct arglist arglist;
 328         union node *argp;
 329         struct strlist *sp;
 330         struct stackmark smark;
 331
 332         setstackmark(&smark);
 333         arglist.lastp = &arglist.list;
 334         for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
 335                 oexitstatus = exitstatus;
 336                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 337                 if (evalskip)
 338                         goto out;
 339         }
 340         *arglist.lastp = NULL;
 341
 342         exitstatus = 0;
 343         loopnest++;
 344         for (sp = arglist.list ; sp ; sp = sp->next) {
 345                 setvar(n->nfor.var, sp->text, 0);
 346                 evaltree(n->nfor.body, flags);
 347                 if (evalskip) {
 348                         if (evalskip == SKIPCONT && --skipcount <= 0) {
 349                                 evalskip = 0;
 350                                 continue;
 351                         }
 352                         if (evalskip == SKIPBREAK && --skipcount <= 0)
 353                                 evalskip = 0;
 354                         break;
 355                 }
 356         }
 357         loopnest--;
 358 out:
 359         popstackmark(&smark);
 360 }
 361
 362
 363
 364 STATIC void
 365 evalcase(union node *n, int flags)
 366 {
 367         union node *cp;
 368         union node *patp;
 369         struct arglist arglist;
 370         struct stackmark smark;
 371
 372         setstackmark(&smark);
 373         arglist.lastp = &arglist.list;
 374         oexitstatus = exitstatus;
 375         exitstatus = 0;
 376         expandarg(n->ncase.expr, &arglist, EXP_TILDE);
 377         for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) {
 378                 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
 379                         if (casematch(patp, arglist.list->text)) {
 380                                 if (evalskip == 0) {
 381                                         evaltree(cp->nclist.body, flags);
 382                                 }
 383                                 goto out;
 384                         }
 385                 }
 386         }
 387 out:
 388         popstackmark(&smark);
 389 }
 390
 391
 392
 393 /*
 394  * Kick off a subshell to evaluate a tree.
 395  */
 396
 397 STATIC void
 398 evalsubshell(union node *n, int flags)
 399 {
 400         struct job *jp;
 401         int backgnd = (n->type == NBACKGND);
 402
 403         expredir(n->nredir.redirect);
 404         if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
 405                         forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
 406                 if (backgnd)
 407                         flags &=~ EV_TESTED;
 408                 redirect(n->nredir.redirect, 0);
 409                 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
 410         }
 411         if (! backgnd) {
 412                 INTOFF;
 413                 exitstatus = waitforjob(jp, (int *)NULL);
 414                 INTON;
 415         }
 416 }
 417
 418
 419
 420 /*
 421  * Compute the names of the files in a redirection list.
 422  */
 423
 424 STATIC void
 425 expredir(union node *n)
 426 {
 427         union node *redir;
 428
 429         for (redir = n ; redir ; redir = redir->nfile.next) {
 430                 struct arglist fn;
 431                 fn.lastp = &fn.list;
 432                 oexitstatus = exitstatus;
 433                 switch (redir->type) {
 434                 case NFROM:
 435                 case NTO:
 436                 case NFROMTO:
 437                 case NAPPEND:
 438                 case NCLOBBER:
 439                         expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
 440                         redir->nfile.expfname = fn.list->text;
 441                         break;
 442                 case NFROMFD:
 443                 case NTOFD:
 444                         if (redir->ndup.vname) {
 445                                 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR);
 446                                 fixredir(redir, fn.list->text, 1);
 447                         }
 448                         break;
 449                 }
 450         }
 451 }
 452
 453
 454
 455 /*
 456  * Evaluate a pipeline.  All the processes in the pipeline are children
 457  * of the process creating the pipeline.  (This differs from some versions
 458  * of the shell, which make the last process in a pipeline the parent
 459  * of all the rest.)
 460  */
 461
 462 STATIC void
 463 evalpipe(union node *n)
 464 {
 465         struct job *jp;
 466         struct nodelist *lp;
 467         int pipelen;
 468         int prevfd;
 469         int pip[2];
 470
 471         TRACE(("evalpipe(%p) called\n", (void *)n));
 472         pipelen = 0;
 473         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
 474                 pipelen++;
 475         INTOFF;
 476         jp = makejob(n, pipelen);
 477         prevfd = -1;
 478         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
 479                 prehash(lp->n);
 480                 pip[1] = -1;
 481                 if (lp->next) {
 482                         if (pipe(pip) < 0) {
 483                                 close(prevfd);
 484                                 error("Pipe call failed: %s", strerror(errno));
 485                         }
 486                 }
 487                 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
 488                         INTON;
 489                         if (prevfd > 0) {
 490                                 dup2(prevfd, 0);
 491                                 close(prevfd);
 492                         }
 493                         if (pip[1] >= 0) {
 494                                 if (!(prevfd >= 0 && pip[0] == 0))
 495                                         close(pip[0]);
 496                                 if (pip[1] != 1) {
 497                                         dup2(pip[1], 1);
 498                                         close(pip[1]);
 499                                 }
 500                         }
 501                         evaltree(lp->n, EV_EXIT);
 502                 }
 503                 if (prevfd >= 0)
 504                         close(prevfd);
 505                 prevfd = pip[0];
 506                 close(pip[1]);
 507         }
 508         INTON;
 509         if (n->npipe.backgnd == 0) {
 510                 INTOFF;
 511                 exitstatus = waitforjob(jp, (int *)NULL);
 512                 TRACE(("evalpipe:  job done exit status %d\n", exitstatus));
 513                 INTON;
 514         }
 515 }
 516
 517
 518
 519 /*
 520  * Execute a command inside back quotes.  If it's a builtin command, we
 521  * want to save its output in a block obtained from malloc.  Otherwise
 522  * we fork off a subprocess and get the output of the command via a pipe.
 523  * Should be called with interrupts off.
 524  */
 525
 526 void
 527 evalbackcmd(union node *n, struct backcmd *result)
 528 {
 529         int pip[2];
 530         struct job *jp;
 531         struct stackmark smark;         /* unnecessary */
 532
 533         setstackmark(&smark);
 534         result->fd = -1;
 535         result->buf = NULL;
 536         result->nleft = 0;
 537         result->jp = NULL;
 538         if (n == NULL) {
 539                 exitstatus = 0;
 540                 goto out;
 541         }
 542         if (n->type == NCMD) {
 543                 exitstatus = oexitstatus;
 544                 evalcommand(n, EV_BACKCMD, result);
 545         } else {
 546                 exitstatus = 0;
 547                 if (pipe(pip) < 0)
 548                         error("Pipe call failed: %s", strerror(errno));
 549                 jp = makejob(n, 1);
 550                 if (forkshell(jp, n, FORK_NOJOB) == 0) {
 551                         FORCEINTON;
 552                         close(pip[0]);
 553                         if (pip[1] != 1) {
 554                                 dup2(pip[1], 1);
 555                                 close(pip[1]);
 556                         }
 557                         evaltree(n, EV_EXIT);
 558                 }
 559                 close(pip[1]);
 560                 result->fd = pip[0];
 561                 result->jp = jp;
 562         }
 563 out:
 564         popstackmark(&smark);
 565         TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
 566                 result->fd, result->buf, result->nleft, result->jp));
 567 }
 568
 569
 570
 571 /*
 572  * Execute a simple command.
 573  */
 574
 575 STATIC void
 576 evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
 577 {
 578         struct stackmark smark;
 579         union node *argp;
 580         struct arglist arglist;
 581         struct arglist varlist;
 582         char **argv;
 583         int argc;
 584         char **envp;
 585         int varflag;
 586         struct strlist *sp;
 587         int mode;
 588         int pip[2];
 589         struct cmdentry cmdentry;
 590         struct job *jp;
 591         struct jmploc jmploc;
 592         struct jmploc *savehandler;
 593         char *savecmdname;
 594         struct shparam saveparam;
 595         struct localvar *savelocalvars;
 596         volatile int e;
 597         char *lastarg;
 598         int realstatus;
 599         int do_clearcmdentry;
 600
 601         /* First expand the arguments. */
 602         TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
 603         setstackmark(&smark);
 604         arglist.lastp = &arglist.list;
 605         varlist.lastp = &varlist.list;
 606         varflag = 1;
 607         do_clearcmdentry = 0;
 608         oexitstatus = exitstatus;
 609         exitstatus = 0;
 610         for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
 611                 char *p = argp->narg.text;
 612                 if (varflag && is_name(*p)) {
 613                         do {
 614                                 p++;
 615                         } while (is_in_name(*p));
 616                         if (*p == '=') {
 617                                 expandarg(argp, &varlist, EXP_VARTILDE);
 618                                 continue;
 619                         }
 620                 }
 621                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 622                 varflag = 0;
 623         }
 624         *arglist.lastp = NULL;
 625         *varlist.lastp = NULL;
 626         expredir(cmd->ncmd.redirect);
 627         argc = 0;
 628         for (sp = arglist.list ; sp ; sp = sp->next)
 629                 argc++;
 630         argv = stalloc(sizeof (char *) * (argc + 1));
 631
 632         for (sp = arglist.list ; sp ; sp = sp->next) {
 633                 TRACE(("evalcommand arg: %s\n", sp->text));
 634                 *argv++ = sp->text;
 635         }
 636         *argv = NULL;
 637         lastarg = NULL;
 638         if (iflag && funcnest == 0 && argc > 0)
 639                 lastarg = argv[-1];
 640         argv -= argc;
 641
 642         /* Print the command if xflag is set. */
 643         if (xflag) {
 644                 char sep = 0;
 645                 const char *p;
 646                 out2str(ps4val());
 647                 for (sp = varlist.list ; sp ; sp = sp->next) {
 648                         if (sep != 0)
 649                                 outc(' ', &errout);
 650                         p = sp->text;
 651                         while (*p != '=' && *p != '\0')
 652                                 out2c(*p++);
 653                         if (*p != '\0') {
 654                                 out2c(*p++);
 655                                 out2qstr(p);
 656                         }
 657                         sep = ' ';
 658                 }
 659                 for (sp = arglist.list ; sp ; sp = sp->next) {
 660                         if (sep != 0)
 661                                 outc(' ', &errout);
 662                         /* Disambiguate command looking like assignment. */
 663                         if (sp == arglist.list &&
 664                                         strchr(sp->text, '=') != NULL &&
 665                                         strchr(sp->text, '\'') == NULL) {
 666                                 out2c('\'');
 667                                 out2str(sp->text);
 668                                 out2c('\'');
 669                         } else
 670                                 out2qstr(sp->text);
 671                         sep = ' ';
 672                 }
 673                 outc('\n', &errout);
 674                 flushout(&errout);
 675         }
 676
 677         /* Now locate the command. */
 678         if (argc == 0) {
 679                 /* Variable assignment(s) without command */
 680                 cmdentry.cmdtype = CMDBUILTIN;
 681                 cmdentry.u.index = BLTINCMD;
 682                 cmdentry.special = 1;
 683         } else {
 684                 static const char PATH[] = "PATH=";
 685                 char *path = pathval();
 686
 687                 /*
 688                  * Modify the command lookup path, if a PATH= assignment
 689                  * is present
 690                  */
 691                 for (sp = varlist.list ; sp ; sp = sp->next)
 692                         if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
 693                                 path = sp->text + sizeof(PATH) - 1;
 694                                 /*
 695                                  * On `PATH=... command`, we need to make
 696                                  * sure that the command isn't using the
 697                                  * non-updated hash table of the outer PATH
 698                                  * setting and we need to make sure that
 699                                  * the hash table isn't filled with items
 700                                  * from the temporary setting.
 701                                  *
 702                                  * It would be better to forbit using and
 703                                  * updating the table while this command
 704                                  * runs, by the command finding mechanism
 705                                  * is heavily integrated with hash handling,
 706                                  * so we just delete the hash before and after
 707                                  * the command runs. Partly deleting like
 708                                  * changepatch() does doesn't seem worth the
 709                                  * bookinging effort, since most such runs add
 710                                  * directories in front of the new PATH.
 711                                  */
 712                                 clearcmdentry(0);
 713                                 do_clearcmdentry = 1;
 714                         }
 715
 716                 find_command(argv[0], &cmdentry, 1, path);
 717                 if (cmdentry.cmdtype == CMDUNKNOWN) {   /* command not found */
 718                         exitstatus = 127;
 719                         flushout(&errout);
 720                         return;
 721                 }
 722                 /* implement the bltin builtin here */
 723                 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) {
 724                         for (;;) {
 725                                 argv++;
 726                                 if (--argc == 0)
 727                                         break;
 728                                 if ((cmdentry.u.index = find_builtin(*argv,
 729                                     &cmdentry.special)) < 0) {
 730                                         outfmt(&errout, "%s: not found\n", *argv);
 731                                         exitstatus = 127;
 732                                         flushout(&errout);
 733                                         return;
 734                                 }
 735                                 if (cmdentry.u.index != BLTINCMD)
 736                                         break;
 737                         }
 738                 }
 739         }
 740
 741         /* Fork off a child process if necessary. */
 742         if (cmd->ncmd.backgnd
 743          || (cmdentry.cmdtype == CMDNORMAL
 744             && ((flags & EV_EXIT) == 0 || have_traps()))
 745          || ((flags & EV_BACKCMD) != 0
 746             && (cmdentry.cmdtype != CMDBUILTIN
 747                  || cmdentry.u.index == CDCMD
 748                  || cmdentry.u.index == DOTCMD
 749                  || cmdentry.u.index == EVALCMD))
 750          || (cmdentry.cmdtype == CMDBUILTIN &&
 751             cmdentry.u.index == COMMANDCMD)) {
 752                 jp = makejob(cmd, 1);
 753                 mode = cmd->ncmd.backgnd;
 754                 if (flags & EV_BACKCMD) {
 755                         mode = FORK_NOJOB;
 756                         if (pipe(pip) < 0)
 757                                 error("Pipe call failed: %s", strerror(errno));
 758                 }
 759                 if (forkshell(jp, cmd, mode) != 0)
 760                         goto parent;    /* at end of routine */
 761                 if (flags & EV_BACKCMD) {
 762                         FORCEINTON;
 763                         close(pip[0]);
 764                         if (pip[1] != 1) {
 765                                 dup2(pip[1], 1);
 766                                 close(pip[1]);
 767                         }
 768                 }
 769                 flags |= EV_EXIT;
 770         }
 771
 772         /* This is the child process if a fork occurred. */
 773         /* Execute the command. */
 774         if (cmdentry.cmdtype == CMDFUNCTION) {
 775 #ifdef DEBUG
 776                 trputs("Shell function:  ");  trargs(argv);
 777 #endif
 778                 redirect(cmd->ncmd.redirect, REDIR_PUSH);
 779                 saveparam = shellparam;
 780                 shellparam.malloc = 0;
 781                 shellparam.reset = 1;
 782                 shellparam.nparam = argc - 1;
 783                 shellparam.p = argv + 1;
 784                 shellparam.optnext = NULL;
 785                 INTOFF;
 786                 savelocalvars = localvars;
 787                 localvars = NULL;
 788                 reffunc(cmdentry.u.func);
 789                 INTON;
 790                 savehandler = handler;
 791                 if (setjmp(jmploc.loc)) {
 792                         if (exception == EXSHELLPROC)
 793                                 freeparam(&saveparam);
 794                         else {
 795                                 freeparam(&shellparam);
 796                                 shellparam = saveparam;
 797                         }
 798                         unreffunc(cmdentry.u.func);
 799                         poplocalvars();
 800                         localvars = savelocalvars;
 801                         handler = savehandler;
 802                         longjmp(handler->loc, 1);
 803                 }
 804                 handler = &jmploc;
 805                 for (sp = varlist.list ; sp ; sp = sp->next)
 806                         mklocal(sp->text);
 807                 funcnest++;
 808                 exitstatus = oexitstatus;
 809                 if (flags & EV_TESTED)
 810                         evaltree(getfuncnode(cmdentry.u.func), EV_TESTED);
 811                 else
 812                         evaltree(getfuncnode(cmdentry.u.func), 0);
 813                 funcnest--;
 814                 INTOFF;
 815                 unreffunc(cmdentry.u.func);
 816                 poplocalvars();
 817                 localvars = savelocalvars;
 818                 freeparam(&shellparam);
 819                 shellparam = saveparam;
 820                 handler = savehandler;
 821                 popredir();
 822                 INTON;
 823                 if (evalskip == SKIPFUNC) {
 824                         evalskip = 0;
 825                         skipcount = 0;
 826                 }
 827                 if (flags & EV_EXIT)
 828                         exitshell(exitstatus);
 829         } else if (cmdentry.cmdtype == CMDBUILTIN) {
 830 #ifdef DEBUG
 831                 trputs("builtin command:  ");  trargs(argv);
 832 #endif
 833                 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
 834                 if (flags == EV_BACKCMD) {
 835                         memout.nleft = 0;
 836                         memout.nextc = memout.buf;
 837                         memout.bufsize = 64;
 838                         mode |= REDIR_BACKQ;
 839                 }
 840                 savecmdname = commandname;
 841                 cmdenviron = varlist.list;
 842                 e = -1;
 843                 savehandler = handler;
 844                 if (setjmp(jmploc.loc)) {
 845                         e = exception;
 846                         exitstatus = (e == EXINT)? SIGINT+128 : 2;
 847                         goto cmddone;
 848                 }
 849                 handler = &jmploc;
 850                 redirect(cmd->ncmd.redirect, mode);
 851                 if (cmdentry.special)
 852                         listsetvar(cmdenviron);
 853                 commandname = argv[0];
 854                 argptr = argv + 1;
 855                 optptr = NULL;                  /* initialize nextopt */
 856                 builtin_flags = flags;
 857                 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
 858                 flushall();
 859 cmddone:
 860                 cmdenviron = NULL;
 861                 out1 = &output;
 862                 out2 = &errout;
 863                 freestdout();
 864                 if (e != EXSHELLPROC) {
 865                         commandname = savecmdname;
 866                         if (flags & EV_EXIT) {
 867                                 exitshell(exitstatus);
 868                         }
 869                 }
 870                 handler = savehandler;
 871                 if (e != -1) {
 872                         if ((e != EXERROR && e != EXEXEC)
 873                             || cmdentry.special)
 874                                 exraise(e);
 875                         FORCEINTON;
 876                 }
 877                 if (cmdentry.u.index != EXECCMD)
 878                         popredir();
 879                 if (flags == EV_BACKCMD) {
 880                         backcmd->buf = memout.buf;
 881                         backcmd->nleft = memout.nextc - memout.buf;
 882                         memout.buf = NULL;
 883                 }
 884         } else {
 885 #ifdef DEBUG
 886                 trputs("normal command:  ");  trargs(argv);
 887 #endif
 888                 clearredir();
 889                 redirect(cmd->ncmd.redirect, 0);
 890                 for (sp = varlist.list ; sp ; sp = sp->next)
 891                         setvareq(sp->text, VEXPORT|VSTACK);
 892                 envp = environment();
 893                 shellexec(argv, envp, pathval(), cmdentry.u.index);
 894                 /*NOTREACHED*/
 895         }
 896         goto out;
 897
 898 parent: /* parent process gets here (if we forked) */
 899         if (mode == 0) {        /* argument to fork */
 900                 INTOFF;
 901                 exitstatus = waitforjob(jp, &realstatus);
 902                 INTON;
 903                 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
 904                         evalskip = SKIPBREAK;
 905                         skipcount = loopnest;
 906                 }
 907         } else if (mode == 2) {
 908                 backcmd->fd = pip[0];
 909                 close(pip[1]);
 910                 backcmd->jp = jp;
 911         }
 912
 913 out:
 914         if (lastarg)
 915                 setvar("_", lastarg, 0);
 916         if (do_clearcmdentry)
 917                 clearcmdentry(0);
 918         popstackmark(&smark);
 919 }
 920
 921
 922
 923 /*
 924  * Search for a command.  This is called before we fork so that the
 925  * location of the command will be available in the parent as well as
 926  * the child.  The check for "goodname" is an overly conservative
 927  * check that the name will not be subject to expansion.
 928  */
 929
 930 STATIC void
 931 prehash(union node *n)
 932 {
 933         struct cmdentry entry;
 934
 935         if (n && n->type == NCMD && n->ncmd.args)
 936                 if (goodname(n->ncmd.args->narg.text))
 937                         find_command(n->ncmd.args->narg.text, &entry, 0,
 938                                      pathval());
 939 }
 940
 941
 942
 943 /*
 944  * Builtin commands.  Builtin commands whose functions are closely
 945  * tied to evaluation are implemented here.
 946  */
 947
 948 /*
 949  * No command given, or a bltin command with no arguments.
 950  */
 951
 952 int
 953 bltincmd(int argc __unused, char **argv __unused)
 954 {
 955         /*
 956          * Preserve exitstatus of a previous possible redirection
 957          * as POSIX mandates
 958          */
 959         return exitstatus;
 960 }
 961
 962
 963 /*
 964  * Handle break and continue commands.  Break, continue, and return are
 965  * all handled by setting the evalskip flag.  The evaluation routines
 966  * above all check this flag, and if it is set they start skipping
 967  * commands rather than executing them.  The variable skipcount is
 968  * the number of loops to break/continue, or the number of function
 969  * levels to return.  (The latter is always 1.)  It should probably
 970  * be an error to break out of more loops than exist, but it isn't
 971  * in the standard shell so we don't make it one here.
 972  */
 973
 974 int
 975 breakcmd(int argc, char **argv)
 976 {
 977         int n = argc > 1 ? number(argv[1]) : 1;
 978
 979         if (n > loopnest)
 980                 n = loopnest;
 981         if (n > 0) {
 982                 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
 983                 skipcount = n;
 984         }
 985         return 0;
 986 }
 987
 988 /*
 989  * The `command' command.
 990  */
 991 int
 992 commandcmd(int argc, char **argv)
 993 {
 994         static char stdpath[] = _PATH_STDPATH;
 995         struct jmploc loc, *old;
 996         struct strlist *sp;
 997         char *path;
 998         int ch;
 999         int cmd = -1;
1000
1001         for (sp = cmdenviron; sp ; sp = sp->next)
1002                 setvareq(sp->text, VEXPORT|VSTACK);
1003         path = pathval();
1004
1005         optind = optreset = 1;
1006         opterr = 0;
1007         while ((ch = getopt(argc, argv, "pvV")) != -1) {
1008                 switch (ch) {
1009                 case 'p':
1010                         path = stdpath;
1011                         break;
1012                 case 'v':
1013                         cmd = TYPECMD_SMALLV;
1014                         break;
1015                 case 'V':
1016                         cmd = TYPECMD_BIGV;
1017                         break;
1018                 case '?':
1019                 default:
1020                         error("unknown option: -%c", optopt);
1021                 }
1022         }
1023         argc -= optind;
1024         argv += optind;
1025
1026         if (cmd != -1) {
1027                 if (argc != 1)
1028                         error("wrong number of arguments");
1029                 return typecmd_impl(2, argv - 1, cmd);
1030         }
1031         if (argc != 0) {
1032                 old = handler;
1033                 handler = &loc;
1034                 if (setjmp(handler->loc) == 0)
1035                         shellexec(argv, environment(), path, 0);
1036                 handler = old;
1037                 if (exception == EXEXEC)
1038                         exit(exerrno);
1039                 exraise(exception);
1040         }
1041
1042         /*
1043          * Do nothing successfully if no command was specified;
1044          * ksh also does this.
1045          */
1046         exit(0);
1047 }
1048
1049
1050 /*
1051  * The return command.
1052  */
1053
1054 int
1055 returncmd(int argc, char **argv)
1056 {
1057         int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1058
1059         if (funcnest) {
1060                 evalskip = SKIPFUNC;
1061                 skipcount = 1;
1062         } else {
1063                 /* skip the rest of the file */
1064                 evalskip = SKIPFILE;
1065                 skipcount = 1;
1066         }
1067         return ret;
1068 }
1069
1070
1071 int
1072 falsecmd(int argc __unused, char **argv __unused)
1073 {
1074         return 1;
1075 }
1076
1077
1078 int
1079 truecmd(int argc __unused, char **argv __unused)
1080 {
1081         return 0;
1082 }
1083
1084
1085 int
1086 execcmd(int argc, char **argv)
1087 {
1088         if (argc > 1) {
1089                 struct strlist *sp;
1090
1091                 iflag = 0;              /* exit on error */
1092                 mflag = 0;
1093                 optschanged();
1094                 for (sp = cmdenviron; sp ; sp = sp->next)
1095                         setvareq(sp->text, VEXPORT|VSTACK);
1096                 shellexec(argv + 1, environment(), pathval(), 0);
1097
1098         }
1099         return 0;
1100 }
1101
1102
1103 int
1104 timescmd(int argc __unused, char **argv __unused)
1105 {
1106         struct rusage ru;
1107         long shumins, shsmins, chumins, chsmins;
1108         double shusecs, shssecs, chusecs, chssecs;
1109
1110         if (getrusage(RUSAGE_SELF, &ru) < 0)
1111                 return 1;
1112         shumins = ru.ru_utime.tv_sec / 60;
1113         shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1114         shsmins = ru.ru_stime.tv_sec / 60;
1115         shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1116         if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1117                 return 1;
1118         chumins = ru.ru_utime.tv_sec / 60;
1119         chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1120         chsmins = ru.ru_stime.tv_sec / 60;
1121         chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1122         out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1123             shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1124         return 0;
1125 }