bin/sh/eval.c

   1 /*-
   2  * Copyright (c) 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)eval.c      8.9 (Berkeley) 6/8/95";
  36 #endif
  37 #endif /* not lint */
  38 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  40
  41 #include <paths.h>
  42 #include <signal.h>
  43 #include <stdlib.h>
  44 #include <unistd.h>
  45 #include <sys/resource.h>
  46 #include <sys/wait.h> /* For WIFSIGNALED(status) */
  47 #include <errno.h>
  48
  49 /*
  50  * Evaluate a command.
  51  */
  52
  53 #include "shell.h"
  54 #include "nodes.h"
  55 #include "syntax.h"
  56 #include "expand.h"
  57 #include "parser.h"
  58 #include "jobs.h"
  59 #include "eval.h"
  60 #include "builtins.h"
  61 #include "options.h"
  62 #include "exec.h"
  63 #include "redir.h"
  64 #include "input.h"
  65 #include "output.h"
  66 #include "trap.h"
  67 #include "var.h"
  68 #include "memalloc.h"
  69 #include "error.h"
  70 #include "show.h"
  71 #include "mystring.h"
  72 #ifndef NO_HISTORY
  73 #include "myhistedit.h"
  74 #endif
  75
  76
  77 int evalskip;                   /* set if we are skipping commands */
  78 int skipcount;                  /* number of levels to skip */
  79 static int loopnest;            /* current loop nesting level */
  80 int funcnest;                   /* depth of function calls */
  81 static int builtin_flags;       /* evalcommand flags for builtins */
  82
  83
  84 char *commandname;
  85 struct strlist *cmdenviron;
  86 int exitstatus;                 /* exit status of last command */
  87 int oexitstatus;                /* saved exit status */
  88
  89
  90 static void evalloop(union node *, int);
  91 static void evalfor(union node *, int);
  92 static union node *evalcase(union node *);
  93 static void evalsubshell(union node *, int);
  94 static void evalredir(union node *, int);
  95 static void exphere(union node *, struct arglist *);
  96 static void expredir(union node *);
  97 static void evalpipe(union node *);
  98 static int is_valid_fast_cmdsubst(union node *n);
  99 static void evalcommand(union node *, int, struct backcmd *);
 100 static void prehash(union node *);
 101
 102
 103 /*
 104  * Called to reset things after an exception.
 105  */
 106
 107 void
 108 reseteval(void)
 109 {
 110         evalskip = 0;
 111         loopnest = 0;
 112 }
 113
 114
 115 /*
 116  * The eval command.
 117  */
 118
 119 int
 120 evalcmd(int argc, char **argv)
 121 {
 122         char *p;
 123         char *concat;
 124         char **ap;
 125
 126         if (argc > 1) {
 127                 p = argv[1];
 128                 if (argc > 2) {
 129                         STARTSTACKSTR(concat);
 130                         ap = argv + 2;
 131                         for (;;) {
 132                                 STPUTS(p, concat);
 133                                 if ((p = *ap++) == NULL)
 134                                         break;
 135                                 STPUTC(' ', concat);
 136                         }
 137                         STPUTC('\0', concat);
 138                         p = grabstackstr(concat);
 139                 }
 140                 evalstring(p, builtin_flags);
 141         } else
 142                 exitstatus = 0;
 143         return exitstatus;
 144 }
 145
 146
 147 /*
 148  * Execute a command or commands contained in a string.
 149  */
 150
 151 void
 152 evalstring(char *s, int flags)
 153 {
 154         union node *n;
 155         struct stackmark smark;
 156         int flags_exit;
 157         int any;
 158
 159         flags_exit = flags & EV_EXIT;
 160         flags &= ~EV_EXIT;
 161         any = 0;
 162         setstackmark(&smark);
 163         setinputstring(s, 1);
 164         while ((n = parsecmd(0)) != NEOF) {
 165                 if (n != NULL && !nflag) {
 166                         if (flags_exit && preadateof())
 167                                 evaltree(n, flags | EV_EXIT);
 168                         else
 169                                 evaltree(n, flags);
 170                         any = 1;
 171                         if (evalskip)
 172                                 break;
 173                 }
 174                 popstackmark(&smark);
 175                 setstackmark(&smark);
 176         }
 177         popfile();
 178         popstackmark(&smark);
 179         if (!any)
 180                 exitstatus = 0;
 181         if (flags_exit)
 182                 exraise(EXEXIT);
 183 }
 184
 185
 186 /*
 187  * Evaluate a parse tree.  The value is left in the global variable
 188  * exitstatus.
 189  */
 190
 191 void
 192 evaltree(union node *n, int flags)
 193 {
 194         int do_etest;
 195         union node *next;
 196         struct stackmark smark;
 197
 198         setstackmark(&smark);
 199         do_etest = 0;
 200         if (n == NULL) {
 201                 TRACE(("evaltree(NULL) called\n"));
 202                 exitstatus = 0;
 203                 goto out;
 204         }
 205         do {
 206                 next = NULL;
 207 #ifndef NO_HISTORY
 208                 displayhist = 1;        /* show history substitutions done with fc */
 209 #endif
 210                 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type));
 211                 switch (n->type) {
 212                 case NSEMI:
 213                         evaltree(n->nbinary.ch1, flags & ~EV_EXIT);
 214                         if (evalskip)
 215                                 goto out;
 216                         next = n->nbinary.ch2;
 217                         break;
 218                 case NAND:
 219                         evaltree(n->nbinary.ch1, EV_TESTED);
 220                         if (evalskip || exitstatus != 0) {
 221                                 goto out;
 222                         }
 223                         next = n->nbinary.ch2;
 224                         break;
 225                 case NOR:
 226                         evaltree(n->nbinary.ch1, EV_TESTED);
 227                         if (evalskip || exitstatus == 0)
 228                                 goto out;
 229                         next = n->nbinary.ch2;
 230                         break;
 231                 case NREDIR:
 232                         evalredir(n, flags);
 233                         break;
 234                 case NSUBSHELL:
 235                         evalsubshell(n, flags);
 236                         do_etest = !(flags & EV_TESTED);
 237                         break;
 238                 case NBACKGND:
 239                         evalsubshell(n, flags);
 240                         break;
 241                 case NIF: {
 242                         evaltree(n->nif.test, EV_TESTED);
 243                         if (evalskip)
 244                                 goto out;
 245                         if (exitstatus == 0)
 246                                 next = n->nif.ifpart;
 247                         else if (n->nif.elsepart)
 248                                 next = n->nif.elsepart;
 249                         else
 250                                 exitstatus = 0;
 251                         break;
 252                 }
 253                 case NWHILE:
 254                 case NUNTIL:
 255                         evalloop(n, flags & ~EV_EXIT);
 256                         break;
 257                 case NFOR:
 258                         evalfor(n, flags & ~EV_EXIT);
 259                         break;
 260                 case NCASE:
 261                         next = evalcase(n);
 262                         break;
 263                 case NCLIST:
 264                         next = n->nclist.body;
 265                         break;
 266                 case NCLISTFALLTHRU:
 267                         if (n->nclist.body) {
 268                                 evaltree(n->nclist.body, flags & ~EV_EXIT);
 269                                 if (evalskip)
 270                                         goto out;
 271                         }
 272                         next = n->nclist.next;
 273                         break;
 274                 case NDEFUN:
 275                         defun(n->narg.text, n->narg.next);
 276                         exitstatus = 0;
 277                         break;
 278                 case NNOT:
 279                         evaltree(n->nnot.com, EV_TESTED);
 280                         if (evalskip)
 281                                 goto out;
 282                         exitstatus = !exitstatus;
 283                         break;
 284
 285                 case NPIPE:
 286                         evalpipe(n);
 287                         do_etest = !(flags & EV_TESTED);
 288                         break;
 289                 case NCMD:
 290                         evalcommand(n, flags, (struct backcmd *)NULL);
 291                         do_etest = !(flags & EV_TESTED);
 292                         break;
 293                 default:
 294                         out1fmt("Node type = %d\n", n->type);
 295                         flushout(&output);
 296                         break;
 297                 }
 298                 n = next;
 299                 popstackmark(&smark);
 300                 setstackmark(&smark);
 301         } while (n != NULL);
 302 out:
 303         popstackmark(&smark);
 304         if (pendingsig)
 305                 dotrap();
 306         if (eflag && exitstatus != 0 && do_etest)
 307                 exitshell(exitstatus);
 308         if (flags & EV_EXIT)
 309                 exraise(EXEXIT);
 310 }
 311
 312
 313 static void
 314 evalloop(union node *n, int flags)
 315 {
 316         int status;
 317
 318         loopnest++;
 319         status = 0;
 320         for (;;) {
 321                 if (!evalskip)
 322                         evaltree(n->nbinary.ch1, EV_TESTED);
 323                 if (evalskip) {
 324                         if (evalskip == SKIPCONT && --skipcount <= 0) {
 325                                 evalskip = 0;
 326                                 continue;
 327                         }
 328                         if (evalskip == SKIPBREAK && --skipcount <= 0)
 329                                 evalskip = 0;
 330                         if (evalskip == SKIPRETURN)
 331                                 status = exitstatus;
 332                         break;
 333                 }
 334                 if (n->type == NWHILE) {
 335                         if (exitstatus != 0)
 336                                 break;
 337                 } else {
 338                         if (exitstatus == 0)
 339                                 break;
 340                 }
 341                 evaltree(n->nbinary.ch2, flags);
 342                 status = exitstatus;
 343         }
 344         loopnest--;
 345         exitstatus = status;
 346 }
 347
 348
 349
 350 static void
 351 evalfor(union node *n, int flags)
 352 {
 353         struct arglist arglist;
 354         union node *argp;
 355         struct strlist *sp;
 356         int status;
 357
 358         arglist.lastp = &arglist.list;
 359         for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
 360                 oexitstatus = exitstatus;
 361                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 362         }
 363         *arglist.lastp = NULL;
 364
 365         loopnest++;
 366         status = 0;
 367         for (sp = arglist.list ; sp ; sp = sp->next) {
 368                 setvar(n->nfor.var, sp->text, 0);
 369                 evaltree(n->nfor.body, flags);
 370                 status = exitstatus;
 371                 if (evalskip) {
 372                         if (evalskip == SKIPCONT && --skipcount <= 0) {
 373                                 evalskip = 0;
 374                                 continue;
 375                         }
 376                         if (evalskip == SKIPBREAK && --skipcount <= 0)
 377                                 evalskip = 0;
 378                         break;
 379                 }
 380         }
 381         loopnest--;
 382         exitstatus = status;
 383 }
 384
 385
 386 /*
 387  * Evaluate a case statement, returning the selected tree.
 388  *
 389  * The exit status needs care to get right.
 390  */
 391
 392 static union node *
 393 evalcase(union node *n)
 394 {
 395         union node *cp;
 396         union node *patp;
 397         struct arglist arglist;
 398
 399         arglist.lastp = &arglist.list;
 400         oexitstatus = exitstatus;
 401         expandarg(n->ncase.expr, &arglist, EXP_TILDE);
 402         for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) {
 403                 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
 404                         if (casematch(patp, arglist.list->text)) {
 405                                 while (cp->nclist.next &&
 406                                     cp->type == NCLISTFALLTHRU &&
 407                                     cp->nclist.body == NULL)
 408                                         cp = cp->nclist.next;
 409                                 if (cp->nclist.next &&
 410                                     cp->type == NCLISTFALLTHRU)
 411                                         return (cp);
 412                                 if (cp->nclist.body == NULL)
 413                                         exitstatus = 0;
 414                                 return (cp->nclist.body);
 415                         }
 416                 }
 417         }
 418         exitstatus = 0;
 419         return (NULL);
 420 }
 421
 422
 423
 424 /*
 425  * Kick off a subshell to evaluate a tree.
 426  */
 427
 428 static void
 429 evalsubshell(union node *n, int flags)
 430 {
 431         struct job *jp;
 432         int backgnd = (n->type == NBACKGND);
 433
 434         oexitstatus = exitstatus;
 435         expredir(n->nredir.redirect);
 436         if ((!backgnd && flags & EV_EXIT && !have_traps()) ||
 437                         forkshell(jp = makejob(n, 1), n, backgnd) == 0) {
 438                 if (backgnd)
 439                         flags &=~ EV_TESTED;
 440                 redirect(n->nredir.redirect, 0);
 441                 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */
 442         } else if (! backgnd) {
 443                 INTOFF;
 444                 exitstatus = waitforjob(jp, (int *)NULL);
 445                 INTON;
 446         } else
 447                 exitstatus = 0;
 448 }
 449
 450
 451 /*
 452  * Evaluate a redirected compound command.
 453  */
 454
 455 static void
 456 evalredir(union node *n, int flags)
 457 {
 458         struct jmploc jmploc;
 459         struct jmploc *savehandler;
 460         volatile int in_redirect = 1;
 461
 462         oexitstatus = exitstatus;
 463         expredir(n->nredir.redirect);
 464         savehandler = handler;
 465         if (setjmp(jmploc.loc)) {
 466                 int e;
 467
 468                 handler = savehandler;
 469                 e = exception;
 470                 popredir();
 471                 if (e == EXERROR || e == EXEXEC) {
 472                         if (in_redirect) {
 473                                 exitstatus = 2;
 474                                 return;
 475                         }
 476                 }
 477                 longjmp(handler->loc, 1);
 478         } else {
 479                 INTOFF;
 480                 handler = &jmploc;
 481                 redirect(n->nredir.redirect, REDIR_PUSH);
 482                 in_redirect = 0;
 483                 INTON;
 484                 evaltree(n->nredir.n, flags);
 485         }
 486         INTOFF;
 487         handler = savehandler;
 488         popredir();
 489         INTON;
 490 }
 491
 492
 493 static void
 494 exphere(union node *redir, struct arglist *fn)
 495 {
 496         struct jmploc jmploc;
 497         struct jmploc *savehandler;
 498         struct localvar *savelocalvars;
 499         int need_longjmp = 0;
 500
 501         redir->nhere.expdoc = nullstr;
 502         savelocalvars = localvars;
 503         localvars = NULL;
 504         forcelocal++;
 505         savehandler = handler;
 506         if (setjmp(jmploc.loc))
 507                 need_longjmp = exception != EXERROR && exception != EXEXEC;
 508         else {
 509                 handler = &jmploc;
 510                 expandarg(redir->nhere.doc, fn, 0);
 511                 redir->nhere.expdoc = fn->list->text;
 512                 INTOFF;
 513         }
 514         handler = savehandler;
 515         forcelocal--;
 516         poplocalvars();
 517         localvars = savelocalvars;
 518         if (need_longjmp)
 519                 longjmp(handler->loc, 1);
 520         INTON;
 521 }
 522
 523
 524 /*
 525  * Compute the names of the files in a redirection list.
 526  */
 527
 528 static void
 529 expredir(union node *n)
 530 {
 531         union node *redir;
 532
 533         for (redir = n ; redir ; redir = redir->nfile.next) {
 534                 struct arglist fn;
 535                 fn.lastp = &fn.list;
 536                 switch (redir->type) {
 537                 case NFROM:
 538                 case NTO:
 539                 case NFROMTO:
 540                 case NAPPEND:
 541                 case NCLOBBER:
 542                         expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
 543                         redir->nfile.expfname = fn.list->text;
 544                         break;
 545                 case NFROMFD:
 546                 case NTOFD:
 547                         if (redir->ndup.vname) {
 548                                 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR);
 549                                 fixredir(redir, fn.list->text, 1);
 550                         }
 551                         break;
 552                 case NXHERE:
 553                         exphere(redir, &fn);
 554                         break;
 555                 }
 556         }
 557 }
 558
 559
 560
 561 /*
 562  * Evaluate a pipeline.  All the processes in the pipeline are children
 563  * of the process creating the pipeline.  (This differs from some versions
 564  * of the shell, which make the last process in a pipeline the parent
 565  * of all the rest.)
 566  */
 567
 568 static void
 569 evalpipe(union node *n)
 570 {
 571         struct job *jp;
 572         struct nodelist *lp;
 573         int pipelen;
 574         int prevfd;
 575         int pip[2];
 576
 577         TRACE(("evalpipe(%p) called\n", (void *)n));
 578         pipelen = 0;
 579         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
 580                 pipelen++;
 581         INTOFF;
 582         jp = makejob(n, pipelen);
 583         prevfd = -1;
 584         for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
 585                 prehash(lp->n);
 586                 pip[1] = -1;
 587                 if (lp->next) {
 588                         if (pipe(pip) < 0) {
 589                                 if (prevfd >= 0)
 590                                         close(prevfd);
 591                                 error("Pipe call failed: %s", strerror(errno));
 592                         }
 593                 }
 594                 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
 595                         INTON;
 596                         if (prevfd > 0) {
 597                                 dup2(prevfd, 0);
 598                                 close(prevfd);
 599                         }
 600                         if (pip[1] >= 0) {
 601                                 if (!(prevfd >= 0 && pip[0] == 0))
 602                                         close(pip[0]);
 603                                 if (pip[1] != 1) {
 604                                         dup2(pip[1], 1);
 605                                         close(pip[1]);
 606                                 }
 607                         }
 608                         evaltree(lp->n, EV_EXIT);
 609                 }
 610                 if (prevfd >= 0)
 611                         close(prevfd);
 612                 prevfd = pip[0];
 613                 if (pip[1] != -1)
 614                         close(pip[1]);
 615         }
 616         INTON;
 617         if (n->npipe.backgnd == 0) {
 618                 INTOFF;
 619                 exitstatus = waitforjob(jp, (int *)NULL);
 620                 TRACE(("evalpipe:  job done exit status %d\n", exitstatus));
 621                 INTON;
 622         } else
 623                 exitstatus = 0;
 624 }
 625
 626
 627
 628 static int
 629 is_valid_fast_cmdsubst(union node *n)
 630 {
 631
 632         return (n->type == NCMD);
 633 }
 634
 635 /*
 636  * Execute a command inside back quotes.  If it's a builtin command, we
 637  * want to save its output in a block obtained from malloc.  Otherwise
 638  * we fork off a subprocess and get the output of the command via a pipe.
 639  * Should be called with interrupts off.
 640  */
 641
 642 void
 643 evalbackcmd(union node *n, struct backcmd *result)
 644 {
 645         int pip[2];
 646         struct job *jp;
 647         struct stackmark smark;
 648         struct jmploc jmploc;
 649         struct jmploc *savehandler;
 650         struct localvar *savelocalvars;
 651
 652         result->fd = -1;
 653         result->buf = NULL;
 654         result->nleft = 0;
 655         result->jp = NULL;
 656         if (n == NULL) {
 657                 exitstatus = 0;
 658                 return;
 659         }
 660         setstackmark(&smark);
 661         exitstatus = oexitstatus;
 662         if (is_valid_fast_cmdsubst(n)) {
 663                 savelocalvars = localvars;
 664                 localvars = NULL;
 665                 forcelocal++;
 666                 savehandler = handler;
 667                 if (setjmp(jmploc.loc)) {
 668                         if (exception == EXERROR || exception == EXEXEC)
 669                                 exitstatus = 2;
 670                         else if (exception != 0) {
 671                                 handler = savehandler;
 672                                 forcelocal--;
 673                                 poplocalvars();
 674                                 localvars = savelocalvars;
 675                                 longjmp(handler->loc, 1);
 676                         }
 677                 } else {
 678                         handler = &jmploc;
 679                         evalcommand(n, EV_BACKCMD, result);
 680                 }
 681                 handler = savehandler;
 682                 forcelocal--;
 683                 poplocalvars();
 684                 localvars = savelocalvars;
 685         } else {
 686                 if (pipe(pip) < 0)
 687                         error("Pipe call failed: %s", strerror(errno));
 688                 jp = makejob(n, 1);
 689                 if (forkshell(jp, n, FORK_NOJOB) == 0) {
 690                         FORCEINTON;
 691                         close(pip[0]);
 692                         if (pip[1] != 1) {
 693                                 dup2(pip[1], 1);
 694                                 close(pip[1]);
 695                         }
 696                         evaltree(n, EV_EXIT);
 697                 }
 698                 close(pip[1]);
 699                 result->fd = pip[0];
 700                 result->jp = jp;
 701         }
 702         popstackmark(&smark);
 703         TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
 704                 result->fd, result->buf, result->nleft, result->jp));
 705 }
 706
 707 static int
 708 mustexpandto(const char *argtext, const char *mask)
 709 {
 710         for (;;) {
 711                 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) {
 712                         argtext++;
 713                         continue;
 714                 }
 715                 if (*argtext == CTLESC)
 716                         argtext++;
 717                 else if (BASESYNTAX[(int)*argtext] == CCTL)
 718                         return (0);
 719                 if (*argtext != *mask)
 720                         return (0);
 721                 if (*argtext == '\0')
 722                         return (1);
 723                 argtext++;
 724                 mask++;
 725         }
 726 }
 727
 728 static int
 729 isdeclarationcmd(struct narg *arg)
 730 {
 731         int have_command = 0;
 732
 733         if (arg == NULL)
 734                 return (0);
 735         while (mustexpandto(arg->text, "command")) {
 736                 have_command = 1;
 737                 arg = &arg->next->narg;
 738                 if (arg == NULL)
 739                         return (0);
 740                 /*
 741                  * To also allow "command -p" and "command --" as part of
 742                  * a declaration command, add code here.
 743                  * We do not do this, as ksh does not do it either and it
 744                  * is not required by POSIX.
 745                  */
 746         }
 747         return (mustexpandto(arg->text, "export") ||
 748             mustexpandto(arg->text, "readonly") ||
 749             (mustexpandto(arg->text, "local") &&
 750                 (have_command || !isfunc("local"))));
 751 }
 752
 753 static void
 754 xtracecommand(struct arglist *varlist, struct arglist *arglist)
 755 {
 756         struct strlist *sp;
 757         char sep = 0;
 758         const char *p, *ps4;
 759
 760         ps4 = expandstr(ps4val());
 761         out2str(ps4 != NULL ? ps4 : ps4val());
 762         for (sp = varlist->list ; sp ; sp = sp->next) {
 763                 if (sep != 0)
 764                         out2c(' ');
 765                 p = strchr(sp->text, '=');
 766                 if (p != NULL) {
 767                         p++;
 768                         outbin(sp->text, p - sp->text, out2);
 769                         out2qstr(p);
 770                 } else
 771                         out2qstr(sp->text);
 772                 sep = ' ';
 773         }
 774         for (sp = arglist->list ; sp ; sp = sp->next) {
 775                 if (sep != 0)
 776                         out2c(' ');
 777                 /* Disambiguate command looking like assignment. */
 778                 if (sp == arglist->list &&
 779                                 strchr(sp->text, '=') != NULL &&
 780                                 strchr(sp->text, '\'') == NULL) {
 781                         out2c('\'');
 782                         out2str(sp->text);
 783                         out2c('\'');
 784                 } else
 785                         out2qstr(sp->text);
 786                 sep = ' ';
 787         }
 788         out2c('\n');
 789         flushout(&errout);
 790 }
 791
 792 /*
 793  * Check if a builtin can safely be executed in the same process,
 794  * even though it should be in a subshell (command substitution).
 795  * Note that jobid, jobs, times and trap can show information not
 796  * available in a child process; this is deliberate.
 797  * The arguments should already have been expanded.
 798  */
 799 static int
 800 safe_builtin(int idx, int argc, char **argv)
 801 {
 802         if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD ||
 803             idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD ||
 804             idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD ||
 805             idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD ||
 806             idx == TYPECMD)
 807                 return (1);
 808         if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD ||
 809             idx == UMASKCMD)
 810                 return (argc <= 1 || (argc == 2 && argv[1][0] == '-'));
 811         if (idx == SETCMD)
 812                 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' ||
 813                     argv[1][0] == '+') && argv[1][1] == 'o' &&
 814                     argv[1][2] == '\0'));
 815         return (0);
 816 }
 817
 818 /*
 819  * Execute a simple command.
 820  * Note: This may or may not return if (flags & EV_EXIT).
 821  */
 822
 823 static void
 824 evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
 825 {
 826         union node *argp;
 827         struct arglist arglist;
 828         struct arglist varlist;
 829         char **argv;
 830         int argc;
 831         char **envp;
 832         int varflag;
 833         struct strlist *sp;
 834         int mode;
 835         int pip[2];
 836         struct cmdentry cmdentry;
 837         struct job *jp;
 838         struct jmploc jmploc;
 839         struct jmploc *savehandler;
 840         char *savecmdname;
 841         struct shparam saveparam;
 842         struct localvar *savelocalvars;
 843         struct parsefile *savetopfile;
 844         volatile int e;
 845         char *lastarg;
 846         int realstatus;
 847         int do_clearcmdentry;
 848         const char *path = pathval();
 849
 850         /* First expand the arguments. */
 851         TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags));
 852         arglist.lastp = &arglist.list;
 853         varlist.lastp = &varlist.list;
 854         varflag = 1;
 855         jp = NULL;
 856         do_clearcmdentry = 0;
 857         oexitstatus = exitstatus;
 858         exitstatus = 0;
 859         for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
 860                 if (varflag && isassignment(argp->narg.text)) {
 861                         expandarg(argp, varflag == 1 ? &varlist : &arglist,
 862                             EXP_VARTILDE);
 863                         continue;
 864                 } else if (varflag == 1)
 865                         varflag = isdeclarationcmd(&argp->narg) ? 2 : 0;
 866                 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 867         }
 868         *arglist.lastp = NULL;
 869         *varlist.lastp = NULL;
 870         expredir(cmd->ncmd.redirect);
 871         argc = 0;
 872         for (sp = arglist.list ; sp ; sp = sp->next)
 873                 argc++;
 874         /* Add one slot at the beginning for tryexec(). */
 875         argv = stalloc(sizeof (char *) * (argc + 2));
 876         argv++;
 877
 878         for (sp = arglist.list ; sp ; sp = sp->next) {
 879                 TRACE(("evalcommand arg: %s\n", sp->text));
 880                 *argv++ = sp->text;
 881         }
 882         *argv = NULL;
 883         lastarg = NULL;
 884         if (iflag && funcnest == 0 && argc > 0)
 885                 lastarg = argv[-1];
 886         argv -= argc;
 887
 888         /* Print the command if xflag is set. */
 889         if (xflag)
 890                 xtracecommand(&varlist, &arglist);
 891
 892         /* Now locate the command. */
 893         if (argc == 0) {
 894                 /* Variable assignment(s) without command */
 895                 cmdentry.cmdtype = CMDBUILTIN;
 896                 cmdentry.u.index = BLTINCMD;
 897                 cmdentry.special = 0;
 898         } else {
 899                 static const char PATH[] = "PATH=";
 900                 int cmd_flags = 0, bltinonly = 0;
 901
 902                 /*
 903                  * Modify the command lookup path, if a PATH= assignment
 904                  * is present
 905                  */
 906                 for (sp = varlist.list ; sp ; sp = sp->next)
 907                         if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) {
 908                                 path = sp->text + sizeof(PATH) - 1;
 909                                 /*
 910                                  * On `PATH=... command`, we need to make
 911                                  * sure that the command isn't using the
 912                                  * non-updated hash table of the outer PATH
 913                                  * setting and we need to make sure that
 914                                  * the hash table isn't filled with items
 915                                  * from the temporary setting.
 916                                  *
 917                                  * It would be better to forbit using and
 918                                  * updating the table while this command
 919                                  * runs, by the command finding mechanism
 920                                  * is heavily integrated with hash handling,
 921                                  * so we just delete the hash before and after
 922                                  * the command runs. Partly deleting like
 923                                  * changepatch() does doesn't seem worth the
 924                                  * bookinging effort, since most such runs add
 925                                  * directories in front of the new PATH.
 926                                  */
 927                                 clearcmdentry();
 928                                 do_clearcmdentry = 1;
 929                         }
 930
 931                 for (;;) {
 932                         if (bltinonly) {
 933                                 cmdentry.u.index = find_builtin(*argv, &cmdentry.special);
 934                                 if (cmdentry.u.index < 0) {
 935                                         cmdentry.u.index = BLTINCMD;
 936                                         argv--;
 937                                         argc++;
 938                                         break;
 939                                 }
 940                         } else
 941                                 find_command(argv[0], &cmdentry, cmd_flags, path);
 942                         /* implement the bltin and command builtins here */
 943                         if (cmdentry.cmdtype != CMDBUILTIN)
 944                                 break;
 945                         if (cmdentry.u.index == BLTINCMD) {
 946                                 if (argc == 1)
 947                                         break;
 948                                 argv++;
 949                                 argc--;
 950                                 bltinonly = 1;
 951                         } else if (cmdentry.u.index == COMMANDCMD) {
 952                                 if (argc == 1)
 953                                         break;
 954                                 if (!strcmp(argv[1], "-p")) {
 955                                         if (argc == 2)
 956                                                 break;
 957                                         if (argv[2][0] == '-') {
 958                                                 if (strcmp(argv[2], "--"))
 959                                                         break;
 960                                                 if (argc == 3)
 961                                                         break;
 962                                                 argv += 3;
 963                                                 argc -= 3;
 964                                         } else {
 965                                                 argv += 2;
 966                                                 argc -= 2;
 967                                         }
 968                                         path = _PATH_STDPATH;
 969                                         clearcmdentry();
 970                                         do_clearcmdentry = 1;
 971                                 } else if (!strcmp(argv[1], "--")) {
 972                                         if (argc == 2)
 973                                                 break;
 974                                         argv += 2;
 975                                         argc -= 2;
 976                                 } else if (argv[1][0] == '-')
 977                                         break;
 978                                 else {
 979                                         argv++;
 980                                         argc--;
 981                                 }
 982                                 cmd_flags |= DO_NOFUNC;
 983                                 bltinonly = 0;
 984                         } else
 985                                 break;
 986                 }
 987                 /*
 988                  * Special builtins lose their special properties when
 989                  * called via 'command'.
 990                  */
 991                 if (cmd_flags & DO_NOFUNC)
 992                         cmdentry.special = 0;
 993         }
 994
 995         /* Fork off a child process if necessary. */
 996         if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN)
 997             && ((flags & EV_EXIT) == 0 || have_traps()))
 998          || ((flags & EV_BACKCMD) != 0
 999             && (cmdentry.cmdtype != CMDBUILTIN ||
1000                  !safe_builtin(cmdentry.u.index, argc, argv)))) {
1001                 jp = makejob(cmd, 1);
1002                 mode = FORK_FG;
1003                 if (flags & EV_BACKCMD) {
1004                         mode = FORK_NOJOB;
1005                         if (pipe(pip) < 0)
1006                                 error("Pipe call failed: %s", strerror(errno));
1007                 }
1008                 if (cmdentry.cmdtype == CMDNORMAL &&
1009                     cmd->ncmd.redirect == NULL &&
1010                     varlist.list == NULL &&
1011                     (mode == FORK_FG || mode == FORK_NOJOB) &&
1012                     !disvforkset() && !iflag && !mflag) {
1013                         vforkexecshell(jp, argv, environment(), path,
1014                             cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL);
1015                         goto parent;
1016                 }
1017                 if (forkshell(jp, cmd, mode) != 0)
1018                         goto parent;    /* at end of routine */
1019                 if (flags & EV_BACKCMD) {
1020                         FORCEINTON;
1021                         close(pip[0]);
1022                         if (pip[1] != 1) {
1023                                 dup2(pip[1], 1);
1024                                 close(pip[1]);
1025                         }
1026                         flags &= ~EV_BACKCMD;
1027                 }
1028                 flags |= EV_EXIT;
1029         }
1030
1031         /* This is the child process if a fork occurred. */
1032         /* Execute the command. */
1033         if (cmdentry.cmdtype == CMDFUNCTION) {
1034 #ifdef DEBUG
1035                 trputs("Shell function:  ");  trargs(argv);
1036 #endif
1037                 saveparam = shellparam;
1038                 shellparam.malloc = 0;
1039                 shellparam.reset = 1;
1040                 shellparam.nparam = argc - 1;
1041                 shellparam.p = argv + 1;
1042                 shellparam.optnext = NULL;
1043                 INTOFF;
1044                 savelocalvars = localvars;
1045                 localvars = NULL;
1046                 reffunc(cmdentry.u.func);
1047                 savehandler = handler;
1048                 if (setjmp(jmploc.loc)) {
1049                         freeparam(&shellparam);
1050                         shellparam = saveparam;
1051                         popredir();
1052                         unreffunc(cmdentry.u.func);
1053                         poplocalvars();
1054                         localvars = savelocalvars;
1055                         funcnest--;
1056                         handler = savehandler;
1057                         longjmp(handler->loc, 1);
1058                 }
1059                 handler = &jmploc;
1060                 funcnest++;
1061                 redirect(cmd->ncmd.redirect, REDIR_PUSH);
1062                 INTON;
1063                 for (sp = varlist.list ; sp ; sp = sp->next)
1064                         mklocal(sp->text);
1065                 exitstatus = oexitstatus;
1066                 evaltree(getfuncnode(cmdentry.u.func),
1067                     flags & (EV_TESTED | EV_EXIT));
1068                 INTOFF;
1069                 unreffunc(cmdentry.u.func);
1070                 poplocalvars();
1071                 localvars = savelocalvars;
1072                 freeparam(&shellparam);
1073                 shellparam = saveparam;
1074                 handler = savehandler;
1075                 funcnest--;
1076                 popredir();
1077                 INTON;
1078                 if (evalskip == SKIPRETURN) {
1079                         evalskip = 0;
1080                         skipcount = 0;
1081                 }
1082                 if (jp)
1083                         exitshell(exitstatus);
1084         } else if (cmdentry.cmdtype == CMDBUILTIN) {
1085 #ifdef DEBUG
1086                 trputs("builtin command:  ");  trargs(argv);
1087 #endif
1088                 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH;
1089                 if (flags == EV_BACKCMD) {
1090                         memout.nleft = 0;
1091                         memout.nextc = memout.buf;
1092                         memout.bufsize = 64;
1093                         mode |= REDIR_BACKQ;
1094                 }
1095                 savecmdname = commandname;
1096                 savetopfile = getcurrentfile();
1097                 cmdenviron = varlist.list;
1098                 e = -1;
1099                 savehandler = handler;
1100                 if (setjmp(jmploc.loc)) {
1101                         e = exception;
1102                         if (e == EXINT)
1103                                 exitstatus = SIGINT+128;
1104                         else if (e != EXEXIT)
1105                                 exitstatus = 2;
1106                         goto cmddone;
1107                 }
1108                 handler = &jmploc;
1109                 redirect(cmd->ncmd.redirect, mode);
1110                 outclearerror(out1);
1111                 /*
1112                  * If there is no command word, redirection errors should
1113                  * not be fatal but assignment errors should.
1114                  */
1115                 if (argc == 0)
1116                         cmdentry.special = 1;
1117                 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET);
1118                 if (argc > 0)
1119                         bltinsetlocale();
1120                 commandname = argv[0];
1121                 argptr = argv + 1;
1122                 nextopt_optptr = NULL;          /* initialize nextopt */
1123                 builtin_flags = flags;
1124                 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv);
1125                 flushall();
1126                 if (outiserror(out1)) {
1127                         warning("write error on stdout");
1128                         if (exitstatus == 0 || exitstatus == 1)
1129                                 exitstatus = 2;
1130                 }
1131 cmddone:
1132                 if (argc > 0)
1133                         bltinunsetlocale();
1134                 cmdenviron = NULL;
1135                 out1 = &output;
1136                 out2 = &errout;
1137                 freestdout();
1138                 handler = savehandler;
1139                 commandname = savecmdname;
1140                 if (jp)
1141                         exitshell(exitstatus);
1142                 if (flags == EV_BACKCMD) {
1143                         backcmd->buf = memout.buf;
1144                         backcmd->nleft = memout.nextc - memout.buf;
1145                         memout.buf = NULL;
1146                 }
1147                 if (cmdentry.u.index != EXECCMD)
1148                         popredir();
1149                 if (e != -1) {
1150                         if ((e != EXERROR && e != EXEXEC)
1151                             || cmdentry.special)
1152                                 exraise(e);
1153                         popfilesupto(savetopfile);
1154                         if (flags != EV_BACKCMD)
1155                                 FORCEINTON;
1156                 }
1157         } else {
1158 #ifdef DEBUG
1159                 trputs("normal command:  ");  trargs(argv);
1160 #endif
1161                 redirect(cmd->ncmd.redirect, 0);
1162                 for (sp = varlist.list ; sp ; sp = sp->next)
1163                         setvareq(sp->text, VEXPORT|VSTACK);
1164                 envp = environment();
1165                 shellexec(argv, envp, path, cmdentry.u.index);
1166                 /*NOTREACHED*/
1167         }
1168         goto out;
1169
1170 parent: /* parent process gets here (if we forked) */
1171         if (mode == FORK_FG) {  /* argument to fork */
1172                 INTOFF;
1173                 exitstatus = waitforjob(jp, &realstatus);
1174                 INTON;
1175                 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) {
1176                         evalskip = SKIPBREAK;
1177                         skipcount = loopnest;
1178                 }
1179         } else if (mode == FORK_NOJOB) {
1180                 backcmd->fd = pip[0];
1181                 close(pip[1]);
1182                 backcmd->jp = jp;
1183         }
1184
1185 out:
1186         if (lastarg)
1187                 setvar("_", lastarg, 0);
1188         if (do_clearcmdentry)
1189                 clearcmdentry();
1190 }
1191
1192
1193
1194 /*
1195  * Search for a command.  This is called before we fork so that the
1196  * location of the command will be available in the parent as well as
1197  * the child.  The check for "goodname" is an overly conservative
1198  * check that the name will not be subject to expansion.
1199  */
1200
1201 static void
1202 prehash(union node *n)
1203 {
1204         struct cmdentry entry;
1205
1206         if (n && n->type == NCMD && n->ncmd.args)
1207                 if (goodname(n->ncmd.args->narg.text))
1208                         find_command(n->ncmd.args->narg.text, &entry, 0,
1209                                      pathval());
1210 }
1211
1212
1213
1214 /*
1215  * Builtin commands.  Builtin commands whose functions are closely
1216  * tied to evaluation are implemented here.
1217  */
1218
1219 /*
1220  * No command given, a bltin command with no arguments, or a bltin command
1221  * with an invalid name.
1222  */
1223
1224 int
1225 bltincmd(int argc, char **argv)
1226 {
1227         if (argc > 1) {
1228                 out2fmt_flush("%s: not found\n", argv[1]);
1229                 return 127;
1230         }
1231         /*
1232          * Preserve exitstatus of a previous possible redirection
1233          * as POSIX mandates
1234          */
1235         return exitstatus;
1236 }
1237
1238
1239 /*
1240  * Handle break and continue commands.  Break, continue, and return are
1241  * all handled by setting the evalskip flag.  The evaluation routines
1242  * above all check this flag, and if it is set they start skipping
1243  * commands rather than executing them.  The variable skipcount is
1244  * the number of loops to break/continue, or the number of function
1245  * levels to return.  (The latter is always 1.)  It should probably
1246  * be an error to break out of more loops than exist, but it isn't
1247  * in the standard shell so we don't make it one here.
1248  */
1249
1250 int
1251 breakcmd(int argc, char **argv)
1252 {
1253         long n;
1254         char *end;
1255
1256         if (argc > 1) {
1257                 /* Allow arbitrarily large numbers. */
1258                 n = strtol(argv[1], &end, 10);
1259                 if (!is_digit(argv[1][0]) || *end != '\0')
1260                         error("Illegal number: %s", argv[1]);
1261         } else
1262                 n = 1;
1263         if (n > loopnest)
1264                 n = loopnest;
1265         if (n > 0) {
1266                 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK;
1267                 skipcount = n;
1268         }
1269         return 0;
1270 }
1271
1272 /*
1273  * The `command' command.
1274  */
1275 int
1276 commandcmd(int argc __unused, char **argv __unused)
1277 {
1278         const char *path;
1279         int ch;
1280         int cmd = -1;
1281
1282         path = bltinlookup("PATH", 1);
1283
1284         while ((ch = nextopt("pvV")) != '\0') {
1285                 switch (ch) {
1286                 case 'p':
1287                         path = _PATH_STDPATH;
1288                         break;
1289                 case 'v':
1290                         cmd = TYPECMD_SMALLV;
1291                         break;
1292                 case 'V':
1293                         cmd = TYPECMD_BIGV;
1294                         break;
1295                 }
1296         }
1297
1298         if (cmd != -1) {
1299                 if (*argptr == NULL || argptr[1] != NULL)
1300                         error("wrong number of arguments");
1301                 return typecmd_impl(2, argptr - 1, cmd, path);
1302         }
1303         if (*argptr != NULL)
1304                 error("commandcmd bad call");
1305
1306         /*
1307          * Do nothing successfully if no command was specified;
1308          * ksh also does this.
1309          */
1310         return 0;
1311 }
1312
1313
1314 /*
1315  * The return command.
1316  */
1317
1318 int
1319 returncmd(int argc, char **argv)
1320 {
1321         int ret = argc > 1 ? number(argv[1]) : oexitstatus;
1322
1323         evalskip = SKIPRETURN;
1324         skipcount = 1;
1325         return ret;
1326 }
1327
1328
1329 int
1330 falsecmd(int argc __unused, char **argv __unused)
1331 {
1332         return 1;
1333 }
1334
1335
1336 int
1337 truecmd(int argc __unused, char **argv __unused)
1338 {
1339         return 0;
1340 }
1341
1342
1343 int
1344 execcmd(int argc, char **argv)
1345 {
1346         /*
1347          * Because we have historically not supported any options,
1348          * only treat "--" specially.
1349          */
1350         if (argc > 1 && strcmp(argv[1], "--") == 0)
1351                 argc--, argv++;
1352         if (argc > 1) {
1353                 struct strlist *sp;
1354
1355                 iflag = 0;              /* exit on error */
1356                 mflag = 0;
1357                 optschanged();
1358                 for (sp = cmdenviron; sp ; sp = sp->next)
1359                         setvareq(sp->text, VEXPORT|VSTACK);
1360                 shellexec(argv + 1, environment(), pathval(), 0);
1361
1362         }
1363         return 0;
1364 }
1365
1366
1367 int
1368 timescmd(int argc __unused, char **argv __unused)
1369 {
1370         struct rusage ru;
1371         long shumins, shsmins, chumins, chsmins;
1372         double shusecs, shssecs, chusecs, chssecs;
1373
1374         if (getrusage(RUSAGE_SELF, &ru) < 0)
1375                 return 1;
1376         shumins = ru.ru_utime.tv_sec / 60;
1377         shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1378         shsmins = ru.ru_stime.tv_sec / 60;
1379         shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1380         if (getrusage(RUSAGE_CHILDREN, &ru) < 0)
1381                 return 1;
1382         chumins = ru.ru_utime.tv_sec / 60;
1383         chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.;
1384         chsmins = ru.ru_stime.tv_sec / 60;
1385         chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.;
1386         out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins,
1387             shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs);
1388         return 0;
1389 }