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  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)eval.c   8.9 (Berkeley) 6/8/95
  37  * $FreeBSD: src/bin/sh/eval.c,v 1.53 2006/06/15 07:57:05 stefanf Exp $
  38  * $DragonFly: src/bin/sh/eval.c,v 1.12 2007/02/04 19:45:24 corecode Exp $
  39  */
  40
  41 #include <sys/time.h>
  42 #include <sys/resource.h>
  43 #include <sys/wait.h> /* For WIFSIGNALED(status) */
  44
  45 #include <errno.h>
  46 #include <paths.h>
  47 #include <signal.h>
  48 #include <stdlib.h>
  49 #include <unistd.h>
  50
  51 /*
  52  * Evaluate a command.
  53  */
  54
  55 #include "shell.h"
  56 #include "nodes.h"
  57 #include "syntax.h"
  58 #include "expand.h"
  59 #include "parser.h"
  60 #include "jobs.h"
  61 #include "eval.h"
  62 #include "builtins.h"
  63 #include "options.h"
  64 #include "exec.h"
  65 #include "redir.h"
  66 #include "input.h"
  67 #include "output.h"
  68 #include "trap.h"
  69 #include "var.h"
  70 #include "memalloc.h"
  71 #include "error.h"
  72 #include "show.h"
  73 #include "mystring.h"
  74 #ifndef NO_HISTORY
  75 #include "myhistedit.h"
  76 #endif
  77
  78
  79 /* flags in argument to evaltree */
  80 #define EV_EXIT 01              /* exit after evaluating tree */
  81 #define EV_TESTED 02            /* exit status is checked; ignore -e flag */
  82 #define EV_BACKCMD 04           /* command executing within back quotes */
  83
  84 int evalskip;                   /* set if we are skipping commands */
  85 STATIC int skipcount;           /* number of levels to skip */
  86 MKINIT int loopnest;            /* current loop nesting level */
  87 int funcnest;                   /* depth of function calls */
  88
  89
  90 const char *commandname;
  91 struct strlist *cmdenviron;
  92 int exitstatus;                 /* exit status of last command */
  93 int oexitstatus;                /* saved exit status */
  94
  95
  96 STATIC void evalloop(union node *, int);
  97 STATIC void evalfor(union node *, int);
  98 STATIC void evalcase(union node *, int);
  99 STATIC void evalsubshell(union node *, int);
 100 STATIC void expredir(union node *);
 101 STATIC void evalpipe(union node *);
 102 STATIC void evalcommand(union node *, int, struct backcmd *);
 103 STATIC void prehash(union node *);
 104
 105
 106 /*
 107  * Called to reset things after an exception.
 108  */
 109
 110 #ifdef mkinit
 111 INCLUDE "eval.h"
 112
 113 RESET {
 114         evalskip = 0;
 115         loopnest = 0;
 116         funcnest = 0;
 117 }
 118
 119 SHELLPROC {
 120         exitstatus = 0;
 121 }
 122 #endif
 123
 124
 125
 126 /*
 127  * The eval command.
 128  */
 129
 130 int
 131 evalcmd(int argc, char **argv)
 132 {
 133         char *p;
 134         char *concat;
 135         char **ap;
 136
 137         if (argc > 1) {
 138                 p = argv[1];
 139                 if (argc > 2) {
 140                         STARTSTACKSTR(concat);
 141                         ap = argv + 2;
 142                         for (;;) {
 143                                 while (*p)
 144                                         STPUTC(*p++, concat);
 145                                 if ((p = *ap++) == NULL)
 146                                         break;
 147                                 STPUTC(' ', concat);
 148                         }
 149                         STPUTC('\0', concat);
 150                         p = grabstackstr(concat);
 151                 }
 152                 evalstring(p);
 153         }
 154         return exitstatus;
 155 }
 156
 157
 158 /*
 159  * Execute a command or commands contained in a string.
 160  */
 161
 162 void
 163 evalstring(char *s)
 164 {
 165         union node *n;
 166         struct stackmark smark;
 167
 168         setstackmark(&smark);
 169         setinputstring(s, 1);
 170         while ((n = parsecmd(0)) != NEOF) {
 171                 evaltree(n, 0);
 172                 popstackmark(&smark);
 173         }
 174         popfile();
 175         popstackmark(&smark);
 176 }
 177
 178
 179
 180 /*
 181  * Evaluate a parse tree.  The value is left in the global variable
 182  * exitstatus.
 183  */
 184
 185 void
 186 evaltree(union node *n, int flags)
 187 {
 188         int do_etest;
 189
 190         do_etest = 0;
 191         if (n == NULL) {
 192                 TRACE(("evaltree(NULL) called\n"));
 193                 exitstatus = 0;
 194                 goto out;
 195         }
 196 #ifndef NO_HISTORY
 197         displayhist = 1;        /* show history substitutions done with fc */
 198 #endif
 199         TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
 200         switch (n->type) {
 201         case NSEMI:
 202                 evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
 203                 if (evalskip)
 204                         goto out;
 205                 evaltree(n->nbinary.ch2, flags);
 206                 break;
 207         case NAND:
 208                 evaltree(n->nbinary.ch1, EV_TESTED);
 209                 if (evalskip || exitstatus != 0) {
 210                         goto out;
 211                 }
 212                 evaltree(n->nbinary.ch2, flags);
 213                 break;
 214         case NOR:
 215                 evaltree(n->nbinary.ch1, EV_TESTED);
 216                 if (evalskip || exitstatus == 0)
 217                         goto out;
 218                 evaltree(n->nbinary.ch2, flags);
 219                 break;
 220         case NREDIR:
 221                 expredir(n->nredir.redirect);
 222                 redirect(n->nredir.redirect, REDIR_PUSH);
 223                 evaltree(n->nredir.n, flags);
 224                 popredir();
 225                 break;
 226         case NSUBSHELL:
 227                 evalsubshell(n, flags);
 228                 do_etest = !(flags & EV_TESTED);
 229                 break;
 230         case NBACKGND:
 231                 evalsubshell(n, flags);
 232                 break;
 233         case NIF: {
 234                 evaltree(n->nif.test, EV_TESTED);
 235                 if (evalskip)
 236                         goto out;
 237                 if (exitstatus == 0)
 238                         evaltree(n->nif.ifpart, flags);
 239                 else if (n->nif.elsepart)
 240                         evaltree(n->nif.elsepart, flags);
 241                 else
 242                         exitstatus = 0;
 243                 break;
 244         }
 245         case NWHILE:
 246         case NUNTIL:
 247                 evalloop(n, flags & ~EV_EXIT);
 248                 break;
 249         case NFOR:
 250                 evalfor(n, flags & ~EV_EXIT);
 251                 break;
 252         case NCASE:
 253                 evalcase(n, flags);
 254                 break;
 255         case NDEFUN:
 256                 defun(n->narg.text, n->narg.next);
 257                 exitstatus = 0;
 258                 break;
 259         case NNOT:
 260                 evaltree(n->nnot.com, EV_TESTED);
 261                 exitstatus = !exitstatus;
 262                 break;
 263
 264         case NPIPE:
 265                 evalpipe(n);
 266                 do_etest = !(flags & EV_TESTED);
 267                 break;
 268         case NCMD:
 269                 evalcommand(n, flags, (struct backcmd *)NULL);
 270                 do_etest = !(flags & EV_TESTED);
 271                 break;
 272         default:
 273                 out1fmt("Node type = %d\n", n->type);
 274                 flushout(&output);
 275                 break;
 276         }
 277 out:
 278         if (pendingsigs)
 279                 dotrap();
 280         if ((flags & EV_EXIT) || (eflag && exitstatus != 0 && do_etest))
 281                 exitshell(exitstatus);
 282 }
 283
 284
 285 STATIC void
 286 evalloop(union node *n, int flags)
 287 {
 288         int status;
 289
 290         loopnest++;
 291         status = 0;
 292         for (;;) {
 293                 evaltree(n->nbinary.ch1, EV_TESTED);
 294                 if (evalskip) {
 295 skipping:         if (evalskip == SKIPCONT && --skipcount <= 0) {
 296                                 evalskip = 0;
 297                                 continue;
 298                         }
 299                         if (evalskip == SKIPBREAK && --skipcount <= 0)
 300                                 evalskip = 0;
 301                         break;
 302                 }
 303                 if (n->type == NWHILE) {
 304                         if (exitstatus != 0)
 305                                 break;
 306                 } else {
 307                         if (exitstatus == 0)
 308                                 break;
 309                 }
 310                 evaltree(n->nbinary.ch2, flags);
 311                 status = exitstatus;
 312                 if (evalskip)
 313                         goto skipping;
 314         }
 315         loopnest--;
 316         exitstatus = status;
 317 }
 318
 319
 320
 321 STATIC void
 322 evalfor(union node *n, int flags)
 323 {
 324         struct arglist arglist;
 325         union node *argp;
 326         struct strlist *sp;
 327         struct stackmark smark;
 328
 329         setstackmark(&smark);
 330         arglist.lastp = &arglist.list;
 331         for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
 332                 oexitstatus = exitstatus;
 333                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 334                 if (evalskip)
 335                         goto out;
 336         }
 337         *arglist.lastp = NULL;
 338
 339         exitstatus = 0;
 340         loopnest++;
 341         for (sp = arglist.list ; sp ; sp = sp->next) {
 342                 setvar(n->nfor.var, sp->text, 0);
 343                 evaltree(n->nfor.body, flags);
 344                 if (evalskip) {
 345                         if (evalskip == SKIPCONT && --skipcount <= 0) {
 346                                 evalskip = 0;
 347                                 continue;
 348                         }
 349                         if (evalskip == SKIPBREAK && --skipcount <= 0)
 350                                 evalskip = 0;
 351                         break;
 352                 }
 353         }
 354         loopnest--;
 355 out:
 356         popstackmark(&smark);
 357 }
 358
 359
 360
 361 STATIC void
 362 evalcase(union node *n, int flags)
 363 {
 364         union node *cp;
 365         union node *patp;
 366         struct arglist arglist;
 367         struct stackmark smark;
 368
 369         setstackmark(&smark);
 370         arglist.lastp = &arglist.list;
 371         oexitstatus = exitstatus;
 372         expandarg(n->ncase.expr, &arglist, EXP_TILDE);
 373         for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) {
 374                 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
 375                         if (casematch(patp, arglist.list->text)) {
 376                                 if (evalskip == 0) {
 377                                         evaltree(cp->nclist.body, flags);
 378                                 }
 379                                 goto out;
 380                         }
 381                 }
 382         }
 383 out:
 384         popstackmark(&smark);
 385 }
 386
 387
 388
 389 /*
 390  * Kick off a subshell to evaluate a tree.
 391  */
 392
 393 STATIC void
 394 evalsubshell(union node *n, int flags)
 395 {
 396         struct job *jp;
 397         int backgnd = (n->type == NBACKGND);
 398
 399         expredir(n->nredir.redirect);
 400         jp = makejob(n, 1);
 401         if (forkshell(jp, n, backgnd) == 0) {
 402                 if (backgnd)
 403                         flags &=~ EV_TESTED;
 404                 redirect(n->nredir.redirect, 0);
 405                 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
 406         }
 407         if (! backgnd) {
 408                 INTOFF;
 409                 exitstatus = waitforjob(jp, (int *)NULL);
 410                 INTON;
 411         }
 412 }
 413
 414
 415
 416 /*
 417  * Compute the names of the files in a redirection list.
 418  */
 419
 420 STATIC void
 421 expredir(union node *n)
 422 {
 423         union node *redir;
 424
 425         for (redir = n ; redir ; redir = redir->nfile.next) {
 426                 struct arglist fn;
 427                 fn.lastp = &fn.list;
 428                 oexitstatus = exitstatus;
 429                 switch (redir->type) {
 430                 case NFROM:
 431                 case NTO:
 432                 case NFROMTO:
 433                 case NAPPEND:
 434                 case NCLOBBER:
 435                         expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
 436                         redir->nfile.expfname = fn.list->text;
 437                         break;
 438                 case NFROMFD:
 439                 case NTOFD:
 440                         if (redir->ndup.vname) {
 441                                 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE);
 442                                 fixredir(redir, fn.list->text, 1);
 443                         }
 444                         break;
 445                 }
 446         }
 447 }
 448
 449
 450
 451 /*
 452  * Evaluate a pipeline.  All the processes in the pipeline are children
 453  * of the process creating the pipeline.  (This differs from some versions
 454  * of the shell, which make the last process in a pipeline the parent
 455  * of all the rest.)
 456  */
 457
 458 STATIC void
 459 evalpipe(union node *n)
 460 {
 461         struct job *jp;
 462         struct nodelist *lp;
 463         int pipelen;
 464         int prevfd;
 465         int pip[2];
 466
 467         TRACE(("evalpipe(%p) called\n", (void *)n));
 468         pipelen = 0;
 469         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
 470                 pipelen++;
 471         INTOFF;
 472         jp = makejob(n, pipelen);
 473         prevfd = -1;
 474         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
 475                 prehash(lp->n);
 476                 pip[1] = -1;
 477                 if (lp->next) {
 478                         if (pipe(pip) < 0) {
 479                                 if (prevfd >= 0)
 480                                         close(prevfd);
 481                                 error("Pipe call failed: %s", strerror(errno));
 482                         }
 483                 }
 484                 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
 485                         INTON;
 486                         if (prevfd > 0) {
 487                                 dup2(prevfd, 0);
 488                                 close(prevfd);
 489                         }
 490                         if (pip[1] >= 0) {
 491                                 if (!(prevfd >= 0 && pip[0] == 0))
 492                                         close(pip[0]);
 493                                 if (pip[1] != 1) {
 494                                         dup2(pip[1], 1);
 495                                         close(pip[1]);
 496                                 }
 497                         }
 498                         evaltree(lp->n, EV_EXIT);
 499                 }
 500                 if (prevfd >= 0)
 501                         close(prevfd);
 502                 prevfd = pip[0];
 503                 close(pip[1]);
 504         }
 505         INTON;
 506         if (n->npipe.backgnd == 0) {
 507                 INTOFF;
 508                 exitstatus = waitforjob(jp, (int *)NULL);
 509                 TRACE(("evalpipe:  job done exit status %d\n", exitstatus));
 510                 INTON;
 511         }
 512 }
 513
 514
 515
 516 /*
 517  * Execute a command inside back quotes.  If it's a builtin command, we
 518  * want to save its output in a block obtained from malloc.  Otherwise
 519  * we fork off a subprocess and get the output of the command via a pipe.
 520  * Should be called with interrupts off.
 521  */
 522
 523 void
 524 evalbackcmd(union node *n, struct backcmd *result)
 525 {
 526         int pip[2];
 527         struct job *jp;
 528         struct stackmark smark;         /* unnecessary */
 529
 530         setstackmark(&smark);
 531         result->fd = -1;
 532         result->buf = NULL;
 533         result->nleft = 0;
 534         result->jp = NULL;
 535         if (n == NULL) {
 536                 exitstatus = 0;
 537                 goto out;
 538         }
 539         if (n->type == NCMD) {
 540                 exitstatus = oexitstatus;
 541                 evalcommand(n, EV_BACKCMD, result);
 542         } else {
 543                 exitstatus = 0;
 544                 if (pipe(pip) < 0)
 545                         error("Pipe call failed: %s", strerror(errno));
 546                 jp = makejob(n, 1);
 547                 if (forkshell(jp, n, FORK_NOJOB) == 0) {
 548                         FORCEINTON;
 549                         close(pip[0]);
 550                         if (pip[1] != 1) {
 551                                 dup2(pip[1], 1);
 552                                 close(pip[1]);
 553                         }
 554                         evaltree(n, EV_EXIT);
 555                 }
 556                 close(pip[1]);
 557                 result->fd = pip[0];
 558                 result->jp = jp;
 559         }
 560 out:
 561         popstackmark(&smark);
 562         TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
 563                 result->fd, result->buf, result->nleft, result->jp));
 564 }
 565
 566
 567
 568 /*
 569  * Execute a simple command.
 570  */
 571
 572 STATIC void
 573 evalcommand(union node *cmd, int flgs, struct backcmd *backcmd)
 574 {
 575         struct stackmark smark;
 576         union node *argp;
 577         struct arglist arglist;
 578         struct arglist varlist;
 579         volatile int flags = flgs;
 580         char **volatile argv;
 581         volatile int argc;
 582         char **envp;
 583         int varflag;
 584         struct strlist *sp;
 585         int mode;
 586         int pip[2];
 587         struct cmdentry cmdentry;
 588         struct job *jp;
 589         struct jmploc jmploc;
 590         struct jmploc *volatile savehandler = NULL;
 591         const char *volatile savecmdname;
 592         volatile struct shparam saveparam;
 593         struct localvar *volatile savelocalvars;
 594         volatile int e;
 595         char *volatile lastarg;
 596         int realstatus;
 597         volatile int do_clearcmdentry;
 598
 599         /* First expand the arguments. */
 600         TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
 601         setstackmark(&smark);
 602         arglist.lastp = &arglist.list;
 603         varlist.lastp = &varlist.list;
 604         varflag = 1;
 605         do_clearcmdentry = 0;
 606         oexitstatus = exitstatus;
 607         exitstatus = 0;
 608         for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
 609                 char *p = argp->narg.text;
 610                 if (varflag && is_name(*p)) {
 611                         do {
 612                                 p++;
 613                         } while (is_in_name(*p));
 614                         if (*p == '=') {
 615                                 expandarg(argp, &varlist, EXP_VARTILDE);
 616                                 continue;
 617                         }
 618                 }
 619                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 620                 varflag = 0;
 621         }
 622         *arglist.lastp = NULL;
 623         *varlist.lastp = NULL;
 624         expredir(cmd->ncmd.redirect);
 625         argc = 0;
 626         for (sp = arglist.list ; sp ; sp = sp->next)
 627                 argc++;
 628         argv = stalloc(sizeof (char *) * (argc + 1));
 629
 630         for (sp = arglist.list ; sp ; sp = sp->next) {
 631                 TRACE(("evalcommand arg: %s\n", sp->text));
 632                 *argv++ = sp->text;
 633         }
 634         *argv = NULL;
 635         lastarg = NULL;
 636         if (iflag && funcnest == 0 && argc > 0)
 637                 lastarg = argv[-1];
 638         argv -= argc;
 639
 640         /* Print the command if xflag is set. */
 641         if (xflag) {
 642                 char sep = 0;
 643                 out2str(ps4val());
 644                 for (sp = varlist.list ; sp ; sp = sp->next) {
 645                         if (sep != 0)
 646                                 outc(' ', &errout);
 647                         out2str(sp->text);
 648                         sep = ' ';
 649                 }
 650                 for (sp = arglist.list ; sp ; sp = sp->next) {
 651                         if (sep != 0)
 652                                 outc(' ', &errout);
 653                         out2str(sp->text);
 654                         sep = ' ';
 655                 }
 656                 outc('\n', &errout);
 657                 flushout(&errout);
 658         }
 659
 660         /* Now locate the command. */
 661         if (argc == 0) {
 662                 /* Variable assignment(s) without command */
 663                 cmdentry.cmdtype = CMDBUILTIN;
 664                 cmdentry.u.index = BLTINCMD;
 665                 cmdentry.special = 1;
 666         } else {
 667                 static const char PATH[] = "PATH=";
 668                 const char *path = pathval();
 669
 670                 /*
 671                  * Modify the command lookup path, if a PATH= assignment
 672                  * is present
 673                  */
 674                 for (sp = varlist.list ; sp ; sp = sp->next)
 675                         if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
 676                                 path = sp->text + sizeof(PATH) - 1;
 677                                 /*
 678                                  * On `PATH=... command`, we need to make
 679                                  * sure that the command isn't using the
 680                                  * non-updated hash table of the outer PATH
 681                                  * setting and we need to make sure that
 682                                  * the hash table isn't filled with items
 683                                  * from the temporary setting.
 684                                  *
 685                                  * It would be better to forbit using and
 686                                  * updating the table while this command
 687                                  * runs, by the command finding mechanism
 688                                  * is heavily integrated with hash handling,
 689                                  * so we just delete the hash before and after
 690                                  * the command runs. Partly deleting like
 691                                  * changepatch() does doesn't seem worth the
 692                                  * bookinging effort, since most such runs add
 693                                  * directories in front of the new PATH.
 694                                  */
 695                                 clearcmdentry(0);
 696                                 do_clearcmdentry = 1;
 697                         }
 698
 699                 find_command(argv[0], &cmdentry, 1, path);
 700                 if (cmdentry.cmdtype == CMDUNKNOWN) {   /* command not found */
 701                         exitstatus = 127;
 702                         flushout(&errout);
 703                         return;
 704                 }
 705                 /* implement the bltin builtin here */
 706                 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) {
 707                         for (;;) {
 708                                 argv++;
 709                                 if (--argc == 0)
 710                                         break;
 711                                 if ((cmdentry.u.index = find_builtin(*argv,
 712                                     &cmdentry.special)) < 0) {
 713                                         outfmt(&errout, "%s: not found\n", *argv);
 714                                         exitstatus = 127;
 715                                         flushout(&errout);
 716                                         return;
 717                                 }
 718                                 if (cmdentry.u.index != BLTINCMD)
 719                                         break;
 720                         }
 721                 }
 722         }
 723
 724         /* Fork off a child process if necessary. */
 725         if (cmd->ncmd.backgnd
 726          || (cmdentry.cmdtype == CMDNORMAL
 727             && ((flags & EV_EXIT) == 0 || Tflag))
 728          || ((flags & EV_BACKCMD) != 0
 729             && (cmdentry.cmdtype != CMDBUILTIN
 730                  || cmdentry.u.index == CDCMD
 731                  || cmdentry.u.index == DOTCMD
 732                  || cmdentry.u.index == EVALCMD))
 733          || (cmdentry.cmdtype == CMDBUILTIN &&
 734             cmdentry.u.index == COMMANDCMD)) {
 735                 jp = makejob(cmd, 1);
 736                 mode = cmd->ncmd.backgnd;
 737                 if (flags & EV_BACKCMD) {
 738                         mode = FORK_NOJOB;
 739                         if (pipe(pip) < 0)
 740                                 error("Pipe call failed: %s", strerror(errno));
 741                 }
 742                 if (forkshell(jp, cmd, mode) != 0)
 743                         goto parent;    /* at end of routine */
 744                 if (flags & EV_BACKCMD) {
 745                         FORCEINTON;
 746                         close(pip[0]);
 747                         if (pip[1] != 1) {
 748                                 dup2(pip[1], 1);
 749                                 close(pip[1]);
 750                         }
 751                 }
 752                 flags |= EV_EXIT;
 753         }
 754
 755         /* This is the child process if a fork occurred. */
 756         /* Execute the command. */
 757         if (cmdentry.cmdtype == CMDFUNCTION) {
 758 #ifdef DEBUG
 759                 trputs("Shell function:  ");  trargs(argv);
 760 #endif
 761                 redirect(cmd->ncmd.redirect, REDIR_PUSH);
 762                 saveparam = shellparam;
 763                 shellparam.malloc = 0;
 764                 shellparam.reset = 1;
 765                 shellparam.nparam = argc - 1;
 766                 shellparam.p = argv + 1;
 767                 shellparam.optnext = NULL;
 768                 INTOFF;
 769                 savelocalvars = localvars;
 770                 localvars = NULL;
 771                 INTON;
 772                 if (setjmp(jmploc.loc)) {
 773                         if (exception == EXSHELLPROC)
 774                                 freeparam(&saveparam);
 775                         else {
 776                                 freeparam(&shellparam);
 777                                 shellparam = saveparam;
 778                         }
 779                         poplocalvars();
 780                         localvars = savelocalvars;
 781                         handler = savehandler;
 782                         longjmp(handler->loc, 1);
 783                 }
 784                 savehandler = handler;
 785                 handler = &jmploc;
 786                 for (sp = varlist.list ; sp ; sp = sp->next)
 787                         mklocal(sp->text);
 788                 funcnest++;
 789                 if (flags & EV_TESTED)
 790                         evaltree(cmdentry.u.func, EV_TESTED);
 791                 else
 792                         evaltree(cmdentry.u.func, 0);
 793                 funcnest--;
 794                 INTOFF;
 795                 poplocalvars();
 796                 localvars = savelocalvars;
 797                 freeparam(&shellparam);
 798                 shellparam = saveparam;
 799                 handler = savehandler;
 800                 popredir();
 801                 INTON;
 802                 if (evalskip == SKIPFUNC) {
 803                         evalskip = 0;
 804                         skipcount = 0;
 805                 }
 806                 if (flags & EV_EXIT)
 807                         exitshell(exitstatus);
 808         } else if (cmdentry.cmdtype == CMDBUILTIN) {
 809 #ifdef DEBUG
 810                 trputs("builtin command:  ");  trargs(argv);
 811 #endif
 812                 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
 813                 if (flags == EV_BACKCMD) {
 814                         memout.nleft = 0;
 815                         memout.nextc = memout.buf;
 816                         memout.bufsize = 64;
 817                         mode |= REDIR_BACKQ;
 818                 }
 819                 savecmdname = commandname;
 820                 cmdenviron = varlist.list;
 821                 e = -1;
 822                 if (setjmp(jmploc.loc)) {
 823                         e = exception;
 824                         exitstatus = (e == EXINT)? SIGINT+128 : 2;
 825                         goto cmddone;
 826                 }
 827                 savehandler = handler;
 828                 handler = &jmploc;
 829                 redirect(cmd->ncmd.redirect, mode);
 830                 if (cmdentry.special)
 831                         listsetvar(cmdenviron);
 832                 commandname = argv[0];
 833                 argptr = argv + 1;
 834                 optptr = NULL;                  /* initialize nextopt */
 835                 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
 836                 flushall();
 837 cmddone:
 838                 cmdenviron = NULL;
 839                 out1 = &output;
 840                 out2 = &errout;
 841                 freestdout();
 842                 if (e != EXSHELLPROC) {
 843                         commandname = savecmdname;
 844                         if (flags & EV_EXIT) {
 845                                 exitshell(exitstatus);
 846                         }
 847                 }
 848                 handler = savehandler;
 849                 if (e != -1) {
 850                         if ((e != EXERROR && e != EXEXEC)
 851                             || cmdentry.special)
 852                                 exraise(e);
 853                         FORCEINTON;
 854                 }
 855                 if (cmdentry.u.index != EXECCMD)
 856                         popredir();
 857                 if (flags == EV_BACKCMD) {
 858                         backcmd->buf = memout.buf;
 859                         backcmd->nleft = memout.nextc - memout.buf;
 860                         memout.buf = NULL;
 861                 }
 862         } else {
 863 #ifdef DEBUG
 864                 trputs("normal command:  ");  trargs(argv);
 865 #endif
 866                 clearredir();
 867                 redirect(cmd->ncmd.redirect, 0);
 868                 for (sp = varlist.list ; sp ; sp = sp->next)
 869                         setvareq(sp->text, VEXPORT|VSTACK);
 870                 envp = environment();
 871                 shellexec(argv, envp, pathval(), cmdentry.u.index);
 872                 /*NOTREACHED*/
 873         }
 874         goto out;
 875
 876 parent: /* parent process gets here (if we forked) */
 877         if (mode == 0) {        /* argument to fork */
 878                 INTOFF;
 879                 exitstatus = waitforjob(jp, &realstatus);
 880                 INTON;
 881                 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
 882                         evalskip = SKIPBREAK;
 883                         skipcount = loopnest;
 884                 }
 885         } else if (mode == 2) {
 886                 backcmd->fd = pip[0];
 887                 close(pip[1]);
 888                 backcmd->jp = jp;
 889         }
 890
 891 out:
 892         if (lastarg)
 893                 setvar("_", lastarg, 0);
 894         if (do_clearcmdentry)
 895                 clearcmdentry(0);
 896         popstackmark(&smark);
 897 }
 898
 899
 900
 901 /*
 902  * Search for a command.  This is called before we fork so that the
 903  * location of the command will be available in the parent as well as
 904  * the child.  The check for "goodname" is an overly conservative
 905  * check that the name will not be subject to expansion.
 906  */
 907
 908 STATIC void
 909 prehash(union node *n)
 910 {
 911         struct cmdentry entry;
 912
 913         if (n && n->type == NCMD && n->ncmd.args)
 914                 if (goodname(n->ncmd.args->narg.text))
 915                         find_command(n->ncmd.args->narg.text, &entry, 0,
 916                                      pathval());
 917 }
 918
 919
 920
 921 /*
 922  * Builtin commands.  Builtin commands whose functions are closely
 923  * tied to evaluation are implemented here.
 924  */
 925
 926 /*
 927  * No command given, or a bltin command with no arguments.
 928  */
 929
 930 int
 931 bltincmd(int argc __unused, char **argv __unused)
 932 {
 933         /*
 934          * Preserve exitstatus of a previous possible redirection
 935          * as POSIX mandates
 936          */
 937         return exitstatus;
 938 }
 939
 940
 941 /*
 942  * Handle break and continue commands.  Break, continue, and return are
 943  * all handled by setting the evalskip flag.  The evaluation routines
 944  * above all check this flag, and if it is set they start skipping
 945  * commands rather than executing them.  The variable skipcount is
 946  * the number of loops to break/continue, or the number of function
 947  * levels to return.  (The latter is always 1.)  It should probably
 948  * be an error to break out of more loops than exist, but it isn't
 949  * in the standard shell so we don't make it one here.
 950  */
 951
 952 int
 953 breakcmd(int argc, char **argv)
 954 {
 955         int n = argc > 1 ? number(argv[1]) : 1;
 956
 957         if (n > loopnest)
 958                 n = loopnest;
 959         if (n > 0) {
 960                 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
 961                 skipcount = n;
 962         }
 963         return 0;
 964 }
 965
 966 /*
 967  * The `command' command.
 968  */
 969 int
 970 commandcmd(int argc, char **argv)
 971 {
 972         static char stdpath[] = _PATH_STDPATH;
 973         struct jmploc loc, *old;
 974         struct strlist *sp;
 975         const char *volatile path;
 976         int ch;
 977         int cmd = -1;
 978
 979         for (sp = cmdenviron; sp ; sp = sp->next)
 980                 setvareq(sp->text, VEXPORT|VSTACK);
 981         path = pathval();
 982
 983         optind = optreset = 1;
 984         opterr = 0;
 985         while ((ch = getopt(argc, argv, "pvV")) != -1) {
 986                 switch (ch) {
 987                 case 'p':
 988                         path = stdpath;
 989                         break;
 990                 case 'v':
 991                         cmd = TYPECMD_SMALLV;
 992                         break;
 993                 case 'V':
 994                         cmd = TYPECMD_BIGV;
 995                         break;
 996                 case '?':
 997                 default:
 998                         error("unknown option: -%c", optopt);
 999                 }
1000         }
1001         argc -= optind;
1002         argv += optind;
1003
1004         if (cmd != -1) {
1005                 if (argc != 1)
1006                         error("wrong number of arguments");
1007                 return typecmd_impl(2, argv - 1, cmd);
1008         }
1009         if (argc != 0) {
1010                 old = handler;
1011                 handler = &loc;
1012                 if (setjmp(handler->loc) == 0)
1013                         shellexec(argv, environment(), path, 0);
1014                 handler = old;
1015                 if (exception == EXEXEC)
1016                         exit(exerrno);
1017                 exraise(exception);
1018         }
1019
1020         /*
1021          * Do nothing successfully if no command was specified;
1022          * ksh also does this.
1023          */
1024         exit(0);
1025 }
1026
1027
1028 /*
1029  * The return command.
1030  */
1031
1032 int
1033 returncmd(int argc, char **argv)
1034 {
1035         int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1036
1037         if (funcnest) {
1038                 evalskip = SKIPFUNC;
1039                 skipcount = 1;
1040         } else {
1041                 /* skip the rest of the file */
1042                 evalskip = SKIPFILE;
1043                 skipcount = 1;
1044         }
1045         return ret;
1046 }
1047
1048
1049 int
1050 falsecmd(int argc __unused, char **argv __unused)
1051 {
1052         return 1;
1053 }
1054
1055
1056 int
1057 truecmd(int argc __unused, char **argv __unused)
1058 {
1059         return 0;
1060 }
1061
1062
1063 int
1064 execcmd(int argc, char **argv)
1065 {
1066         if (argc > 1) {
1067                 struct strlist *sp;
1068
1069                 iflag = 0;              /* exit on error */
1070                 mflag = 0;
1071                 optschanged();
1072                 for (sp = cmdenviron; sp ; sp = sp->next)
1073                         setvareq(sp->text, VEXPORT|VSTACK);
1074                 shellexec(argv + 1, environment(), pathval(), 0);
1075
1076         }
1077         return 0;
1078 }
1079
1080
1081 int
1082 timescmd(int argc __unused, char **argv __unused)
1083 {
1084         struct rusage ru;
1085         long shumins, shsmins, chumins, chsmins;
1086         double shusecs, shssecs, chusecs, chssecs;
1087
1088         if (getrusage(RUSAGE_SELF, &ru) < 0)
1089                 return 1;
1090         shumins = ru.ru_utime.tv_sec / 60;
1091         shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1092         shsmins = ru.ru_stime.tv_sec / 60;
1093         shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1094         if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1095                 return 1;
1096         chumins = ru.ru_utime.tv_sec / 60;
1097         chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1098         chsmins = ru.ru_stime.tv_sec / 60;
1099         chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1100         out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1101             shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1102         return 0;
1103 }