eval.c revision 45221
1189251Ssam/*- 2189251Ssam * Copyright (c) 1993 3189251Ssam * The Regents of the University of California. All rights reserved. 4189251Ssam * 5252726Srpaulo * This code is derived from software contributed to Berkeley by 6252726Srpaulo * Kenneth Almquist. 7189251Ssam * 8189251Ssam * Redistribution and use in source and binary forms, with or without 9189251Ssam * modification, are permitted provided that the following conditions 10251848Spluknet * are met: 11189251Ssam * 1. Redistributions of source code must retain the above copyright 12189251Ssam * notice, this list of conditions and the following disclaimer. 13189251Ssam * 2. Redistributions in binary form must reproduce the above copyright 14189251Ssam * notice, this list of conditions and the following disclaimer in the 15189251Ssam * documentation and/or other materials provided with the distribution. 16189251Ssam * 3. All advertising materials mentioning features or use of this software 17189251Ssam * 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 37#ifndef lint 38#if 0 39static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 40#endif 41static const char rcsid[] = 42 "$Id: eval.c,v 1.15 1998/05/18 06:43:34 charnier Exp $"; 43#endif /* not lint */ 44 45#include <signal.h> 46#include <unistd.h> 47 48/* 49 * Evaluate a command. 50 */ 51 52#include "shell.h" 53#include "nodes.h" 54#include "syntax.h" 55#include "expand.h" 56#include "parser.h" 57#include "jobs.h" 58#include "eval.h" 59#include "builtins.h" 60#include "options.h" 61#include "exec.h" 62#include "redir.h" 63#include "input.h" 64#include "output.h" 65#include "trap.h" 66#include "var.h" 67#include "memalloc.h" 68#include "error.h" 69#include "show.h" 70#include "mystring.h" 71#ifndef NO_HISTORY 72#include "myhistedit.h" 73#endif 74 75 76/* flags in argument to evaltree */ 77#define EV_EXIT 01 /* exit after evaluating tree */ 78#define EV_TESTED 02 /* exit status is checked; ignore -e flag */ 79#define EV_BACKCMD 04 /* command executing within back quotes */ 80 81MKINIT int evalskip; /* set if we are skipping commands */ 82STATIC int skipcount; /* number of levels to skip */ 83MKINIT int loopnest; /* current loop nesting level */ 84int funcnest; /* depth of function calls */ 85 86 87char *commandname; 88struct strlist *cmdenviron; 89int exitstatus; /* exit status of last command */ 90int oexitstatus; /* saved exit status */ 91 92 93STATIC void evalloop __P((union node *)); 94STATIC void evalfor __P((union node *)); 95STATIC void evalcase __P((union node *, int)); 96STATIC void evalsubshell __P((union node *, int)); 97STATIC void expredir __P((union node *)); 98STATIC void evalpipe __P((union node *)); 99STATIC void evalcommand __P((union node *, int, struct backcmd *)); 100STATIC void prehash __P((union node *)); 101 102 103/* 104 * Called to reset things after an exception. 105 */ 106 107#ifdef mkinit 108INCLUDE "eval.h" 109 110RESET { 111 evalskip = 0; 112 loopnest = 0; 113 funcnest = 0; 114} 115 116SHELLPROC { 117 exitstatus = 0; 118} 119#endif 120 121 122 123/* 124 * The eval commmand. 125 */ 126 127int 128evalcmd(argc, argv) 129 int argc; 130 char **argv; 131{ 132 char *p; 133 char *concat; 134 char **ap; 135 136 if (argc > 1) { 137 p = argv[1]; 138 if (argc > 2) { 139 STARTSTACKSTR(concat); 140 ap = argv + 2; 141 for (;;) { 142 while (*p) 143 STPUTC(*p++, concat); 144 if ((p = *ap++) == NULL) 145 break; 146 STPUTC(' ', concat); 147 } 148 STPUTC('\0', concat); 149 p = grabstackstr(concat); 150 } 151 evalstring(p); 152 } 153 return exitstatus; 154} 155 156 157/* 158 * Execute a command or commands contained in a string. 159 */ 160 161void 162evalstring(s) 163 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 185void 186evaltree(n, flags) 187 union node *n; 188 int flags; 189{ 190 if (n == NULL) { 191 TRACE(("evaltree(NULL) called\n")); 192 exitstatus = 0; 193 goto out; 194 } 195#ifndef NO_HISTORY 196 displayhist = 1; /* show history substitutions done with fc */ 197#endif 198 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type)); 199 switch (n->type) { 200 case NSEMI: 201 evaltree(n->nbinary.ch1, 0); 202 if (evalskip) 203 goto out; 204 evaltree(n->nbinary.ch2, flags); 205 break; 206 case NAND: 207 evaltree(n->nbinary.ch1, EV_TESTED); 208 if (evalskip || exitstatus != 0) { 209 flags |= EV_TESTED; 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 break; 229 case NBACKGND: 230 evalsubshell(n, flags); 231 break; 232 case NIF: { 233 evaltree(n->nif.test, EV_TESTED); 234 if (evalskip) 235 goto out; 236 if (exitstatus == 0) 237 evaltree(n->nif.ifpart, flags); 238 else if (n->nif.elsepart) 239 evaltree(n->nif.elsepart, flags); 240 else 241 exitstatus = 0; 242 break; 243 } 244 case NWHILE: 245 case NUNTIL: 246 evalloop(n); 247 break; 248 case NFOR: 249 evalfor(n); 250 break; 251 case NCASE: 252 evalcase(n, flags); 253 break; 254 case NDEFUN: 255 defun(n->narg.text, n->narg.next); 256 exitstatus = 0; 257 break; 258 case NNOT: 259 evaltree(n->nnot.com, EV_TESTED); 260 exitstatus = !exitstatus; 261 break; 262 263 case NPIPE: 264 evalpipe(n); 265 break; 266 case NCMD: 267 evalcommand(n, flags, (struct backcmd *)NULL); 268 break; 269 default: 270 out1fmt("Node type = %d\n", n->type); 271 flushout(&output); 272 break; 273 } 274out: 275 if (pendingsigs) 276 dotrap(); 277 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 278 exitshell(exitstatus); 279} 280 281 282STATIC void 283evalloop(n) 284 union node *n; 285{ 286 int status; 287 288 loopnest++; 289 status = 0; 290 for (;;) { 291 evaltree(n->nbinary.ch1, EV_TESTED); 292 if (evalskip) { 293skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 294 evalskip = 0; 295 continue; 296 } 297 if (evalskip == SKIPBREAK && --skipcount <= 0) 298 evalskip = 0; 299 break; 300 } 301 if (n->type == NWHILE) { 302 if (exitstatus != 0) 303 break; 304 } else { 305 if (exitstatus == 0) 306 break; 307 } 308 evaltree(n->nbinary.ch2, 0); 309 status = exitstatus; 310 if (evalskip) 311 goto skipping; 312 } 313 loopnest--; 314 exitstatus = status; 315} 316 317 318 319STATIC void 320evalfor(n) 321 union node *n; 322{ 323 struct arglist arglist; 324 union node *argp; 325 struct strlist *sp; 326 struct stackmark smark; 327 328 setstackmark(&smark); 329 arglist.lastp = &arglist.list; 330 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 331 oexitstatus = exitstatus; 332 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 333 if (evalskip) 334 goto out; 335 } 336 *arglist.lastp = NULL; 337 338 exitstatus = 0; 339 loopnest++; 340 for (sp = arglist.list ; sp ; sp = sp->next) { 341 setvar(n->nfor.var, sp->text, 0); 342 evaltree(n->nfor.body, 0); 343 if (evalskip) { 344 if (evalskip == SKIPCONT && --skipcount <= 0) { 345 evalskip = 0; 346 continue; 347 } 348 if (evalskip == SKIPBREAK && --skipcount <= 0) 349 evalskip = 0; 350 break; 351 } 352 } 353 loopnest--; 354out: 355 popstackmark(&smark); 356} 357 358 359 360STATIC void 361evalcase(n, flags) 362 union node *n; 363 int flags; 364{ 365 union node *cp; 366 union node *patp; 367 struct arglist arglist; 368 struct stackmark smark; 369 370 setstackmark(&smark); 371 arglist.lastp = &arglist.list; 372 oexitstatus = exitstatus; 373 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 374 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 375 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 376 if (casematch(patp, arglist.list->text)) { 377 if (evalskip == 0) { 378 evaltree(cp->nclist.body, flags); 379 } 380 goto out; 381 } 382 } 383 } 384out: 385 popstackmark(&smark); 386} 387 388 389 390/* 391 * Kick off a subshell to evaluate a tree. 392 */ 393 394STATIC void 395evalsubshell(n, flags) 396 union node *n; 397 int flags; 398{ 399 struct job *jp; 400 int backgnd = (n->type == NBACKGND); 401 402 expredir(n->nredir.redirect); 403 jp = makejob(n, 1); 404 if (forkshell(jp, n, backgnd) == 0) { 405 if (backgnd) 406 flags &=~ EV_TESTED; 407 redirect(n->nredir.redirect, 0); 408 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 409 } 410 if (! backgnd) { 411 INTOFF; 412 exitstatus = waitforjob(jp); 413 INTON; 414 } 415} 416 417 418 419/* 420 * Compute the names of the files in a redirection list. 421 */ 422 423STATIC void 424expredir(n) 425 union node *n; 426{ 427 union node *redir; 428 429 for (redir = n ; redir ; redir = redir->nfile.next) { 430 struct arglist fn; 431 fn.lastp = &fn.list; 432 oexitstatus = exitstatus; 433 switch (redir->type) { 434 case NFROM: 435 case NTO: 436 case NAPPEND: 437 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 438 redir->nfile.expfname = fn.list->text; 439 break; 440 case NFROMFD: 441 case NTOFD: 442 if (redir->ndup.vname) { 443 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 444 fixredir(redir, fn.list->text, 1); 445 } 446 break; 447 } 448 } 449} 450 451 452 453/* 454 * Evaluate a pipeline. All the processes in the pipeline are children 455 * of the process creating the pipeline. (This differs from some versions 456 * of the shell, which make the last process in a pipeline the parent 457 * of all the rest.) 458 */ 459 460STATIC void 461evalpipe(n) 462 union node *n; 463{ 464 struct job *jp; 465 struct nodelist *lp; 466 int pipelen; 467 int prevfd; 468 int pip[2]; 469 470 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 471 pipelen = 0; 472 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 473 pipelen++; 474 INTOFF; 475 jp = makejob(n, pipelen); 476 prevfd = -1; 477 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 478 prehash(lp->n); 479 pip[1] = -1; 480 if (lp->next) { 481 if (pipe(pip) < 0) { 482 close(prevfd); 483 error("Pipe call failed"); 484 } 485 } 486 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 487 INTON; 488 if (prevfd > 0) { 489 close(0); 490 copyfd(prevfd, 0); 491 close(prevfd); 492 } 493 if (pip[1] >= 0) { 494 close(pip[0]); 495 if (pip[1] != 1) { 496 close(1); 497 copyfd(pip[1], 1); 498 close(pip[1]); 499 } 500 } 501 evaltree(lp->n, EV_EXIT); 502 } 503 if (prevfd >= 0) 504 close(prevfd); 505 prevfd = pip[0]; 506 close(pip[1]); 507 } 508 INTON; 509 if (n->npipe.backgnd == 0) { 510 INTOFF; 511 exitstatus = waitforjob(jp); 512 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 513 INTON; 514 } 515} 516 517 518 519/* 520 * Execute a command inside back quotes. If it's a builtin command, we 521 * want to save its output in a block obtained from malloc. Otherwise 522 * we fork off a subprocess and get the output of the command via a pipe. 523 * Should be called with interrupts off. 524 */ 525 526void 527evalbackcmd(n, result) 528 union node *n; 529 struct backcmd *result; 530{ 531 int pip[2]; 532 struct job *jp; 533 struct stackmark smark; /* unnecessary */ 534 535 setstackmark(&smark); 536 result->fd = -1; 537 result->buf = NULL; 538 result->nleft = 0; 539 result->jp = NULL; 540 if (n == NULL) { 541 exitstatus = 0; 542 goto out; 543 } 544 if (n->type == NCMD) { 545 exitstatus = oexitstatus; 546 evalcommand(n, EV_BACKCMD, result); 547 } else { 548 exitstatus = 0; 549 if (pipe(pip) < 0) 550 error("Pipe call failed"); 551 jp = makejob(n, 1); 552 if (forkshell(jp, n, FORK_NOJOB) == 0) { 553 FORCEINTON; 554 close(pip[0]); 555 if (pip[1] != 1) { 556 close(1); 557 copyfd(pip[1], 1); 558 close(pip[1]); 559 } 560 evaltree(n, EV_EXIT); 561 } 562 close(pip[1]); 563 result->fd = pip[0]; 564 result->jp = jp; 565 } 566out: 567 popstackmark(&smark); 568 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 569 result->fd, result->buf, result->nleft, result->jp)); 570} 571 572 573 574/* 575 * Execute a simple command. 576 */ 577 578STATIC void 579evalcommand(cmd, flags, backcmd) 580 union node *cmd; 581 int flags; 582 struct backcmd *backcmd; 583{ 584 struct stackmark smark; 585 union node *argp; 586 struct arglist arglist; 587 struct arglist varlist; 588 char **argv; 589 int argc; 590 char **envp; 591 int varflag; 592 struct strlist *sp; 593 int mode; 594 int pip[2]; 595 struct cmdentry cmdentry; 596 struct job *jp; 597 struct jmploc jmploc; 598 struct jmploc *volatile savehandler; 599 char *volatile savecmdname; 600 volatile struct shparam saveparam; 601 struct localvar *volatile savelocalvars; 602 volatile int e; 603 char *lastarg; 604#if __GNUC__ 605 /* Avoid longjmp clobbering */ 606 (void) &argv; 607 (void) &argc; 608 (void) &lastarg; 609 (void) &flags; 610#endif 611 612 /* First expand the arguments. */ 613 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 614 setstackmark(&smark); 615 arglist.lastp = &arglist.list; 616 varlist.lastp = &varlist.list; 617 varflag = 1; 618 oexitstatus = exitstatus; 619 exitstatus = 0; 620 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 621 char *p = argp->narg.text; 622 if (varflag && is_name(*p)) { 623 do { 624 p++; 625 } while (is_in_name(*p)); 626 if (*p == '=') { 627 expandarg(argp, &varlist, EXP_VARTILDE); 628 continue; 629 } 630 } 631 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 632 varflag = 0; 633 } 634 *arglist.lastp = NULL; 635 *varlist.lastp = NULL; 636 expredir(cmd->ncmd.redirect); 637 argc = 0; 638 for (sp = arglist.list ; sp ; sp = sp->next) 639 argc++; 640 argv = stalloc(sizeof (char *) * (argc + 1)); 641 642 for (sp = arglist.list ; sp ; sp = sp->next) { 643 TRACE(("evalcommand arg: %s\n", sp->text)); 644 *argv++ = sp->text; 645 } 646 *argv = NULL; 647 lastarg = NULL; 648 if (iflag && funcnest == 0 && argc > 0) 649 lastarg = argv[-1]; 650 argv -= argc; 651 652 /* Print the command if xflag is set. */ 653 if (xflag) { 654 outc('+', &errout); 655 for (sp = varlist.list ; sp ; sp = sp->next) { 656 outc(' ', &errout); 657 out2str(sp->text); 658 } 659 for (sp = arglist.list ; sp ; sp = sp->next) { 660 outc(' ', &errout); 661 out2str(sp->text); 662 } 663 outc('\n', &errout); 664 flushout(&errout); 665 } 666 667 /* Now locate the command. */ 668 if (argc == 0) { 669 cmdentry.cmdtype = CMDBUILTIN; 670 cmdentry.u.index = BLTINCMD; 671 } else { 672 static const char PATH[] = "PATH="; 673 char *path = pathval(); 674 675 /* 676 * Modify the command lookup path, if a PATH= assignment 677 * is present 678 */ 679 for (sp = varlist.list ; sp ; sp = sp->next) 680 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) 681 path = sp->text + sizeof(PATH) - 1; 682 683 find_command(argv[0], &cmdentry, 1, path); 684 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 685 exitstatus = 127; 686 flushout(&errout); 687 return; 688 } 689 /* implement the bltin builtin here */ 690 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 691 for (;;) { 692 argv++; 693 if (--argc == 0) 694 break; 695 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 696 outfmt(&errout, "%s: not found\n", *argv); 697 exitstatus = 127; 698 flushout(&errout); 699 return; 700 } 701 if (cmdentry.u.index != BLTINCMD) 702 break; 703 } 704 } 705 } 706 707 /* Fork off a child process if necessary. */ 708 if (cmd->ncmd.backgnd 709 || (cmdentry.cmdtype == CMDNORMAL 710 && ((flags & EV_EXIT) == 0 || Tflag)) 711 || ((flags & EV_BACKCMD) != 0 712 && (cmdentry.cmdtype != CMDBUILTIN 713 || cmdentry.u.index == DOTCMD 714 || cmdentry.u.index == EVALCMD))) { 715 jp = makejob(cmd, 1); 716 mode = cmd->ncmd.backgnd; 717 if (flags & EV_BACKCMD) { 718 mode = FORK_NOJOB; 719 if (pipe(pip) < 0) 720 error("Pipe call failed"); 721 } 722 if (forkshell(jp, cmd, mode) != 0) 723 goto parent; /* at end of routine */ 724 if (flags & EV_BACKCMD) { 725 FORCEINTON; 726 close(pip[0]); 727 if (pip[1] != 1) { 728 close(1); 729 copyfd(pip[1], 1); 730 close(pip[1]); 731 } 732 } 733 flags |= EV_EXIT; 734 } 735 736 /* This is the child process if a fork occurred. */ 737 /* Execute the command. */ 738 if (cmdentry.cmdtype == CMDFUNCTION) { 739#ifdef DEBUG 740 trputs("Shell function: "); trargs(argv); 741#endif 742 redirect(cmd->ncmd.redirect, REDIR_PUSH); 743 saveparam = shellparam; 744 shellparam.malloc = 0; 745 shellparam.reset = 1; 746 shellparam.nparam = argc - 1; 747 shellparam.p = argv + 1; 748 shellparam.optnext = NULL; 749 INTOFF; 750 savelocalvars = localvars; 751 localvars = NULL; 752 INTON; 753 if (setjmp(jmploc.loc)) { 754 if (exception == EXSHELLPROC) 755 freeparam((struct shparam *)&saveparam); 756 else { 757 freeparam(&shellparam); 758 shellparam = saveparam; 759 } 760 poplocalvars(); 761 localvars = savelocalvars; 762 handler = savehandler; 763 longjmp(handler->loc, 1); 764 } 765 savehandler = handler; 766 handler = &jmploc; 767 for (sp = varlist.list ; sp ; sp = sp->next) 768 mklocal(sp->text); 769 funcnest++; 770 if (flags & EV_TESTED) 771 evaltree(cmdentry.u.func, EV_TESTED); 772 else 773 evaltree(cmdentry.u.func, 0); 774 funcnest--; 775 INTOFF; 776 poplocalvars(); 777 localvars = savelocalvars; 778 freeparam(&shellparam); 779 shellparam = saveparam; 780 handler = savehandler; 781 popredir(); 782 INTON; 783 if (evalskip == SKIPFUNC) { 784 evalskip = 0; 785 skipcount = 0; 786 } 787 if (flags & EV_EXIT) 788 exitshell(exitstatus); 789 } else if (cmdentry.cmdtype == CMDBUILTIN) { 790#ifdef DEBUG 791 trputs("builtin command: "); trargs(argv); 792#endif 793 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 794 if (flags == EV_BACKCMD) { 795 memout.nleft = 0; 796 memout.nextc = memout.buf; 797 memout.bufsize = 64; 798 mode |= REDIR_BACKQ; 799 } 800 redirect(cmd->ncmd.redirect, mode); 801 savecmdname = commandname; 802 cmdenviron = varlist.list; 803 e = -1; 804 if (setjmp(jmploc.loc)) { 805 e = exception; 806 exitstatus = (e == EXINT)? SIGINT+128 : 2; 807 goto cmddone; 808 } 809 savehandler = handler; 810 handler = &jmploc; 811 commandname = argv[0]; 812 argptr = argv + 1; 813 optptr = NULL; /* initialize nextopt */ 814 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 815 flushall(); 816cmddone: 817 out1 = &output; 818 out2 = &errout; 819 freestdout(); 820 if (e != EXSHELLPROC) { 821 commandname = savecmdname; 822 if (flags & EV_EXIT) { 823 exitshell(exitstatus); 824 } 825 } 826 handler = savehandler; 827 if (e != -1) { 828 if ((e != EXERROR && e != EXEXEC) 829 || cmdentry.u.index == BLTINCMD 830 || cmdentry.u.index == DOTCMD 831 || cmdentry.u.index == EVALCMD 832#ifndef NO_HISTORY 833 || cmdentry.u.index == HISTCMD 834#endif 835 || cmdentry.u.index == EXECCMD) 836 exraise(e); 837 FORCEINTON; 838 } 839 if (cmdentry.u.index != EXECCMD) 840 popredir(); 841 if (flags == EV_BACKCMD) { 842 backcmd->buf = memout.buf; 843 backcmd->nleft = memout.nextc - memout.buf; 844 memout.buf = NULL; 845 } 846 } else { 847#ifdef DEBUG 848 trputs("normal command: "); trargs(argv); 849#endif 850 clearredir(); 851 redirect(cmd->ncmd.redirect, 0); 852 for (sp = varlist.list ; sp ; sp = sp->next) 853 setvareq(sp->text, VEXPORT|VSTACK); 854 envp = environment(); 855 shellexec(argv, envp, pathval(), cmdentry.u.index); 856 /*NOTREACHED*/ 857 } 858 goto out; 859 860parent: /* parent process gets here (if we forked) */ 861 if (mode == 0) { /* argument to fork */ 862 INTOFF; 863 exitstatus = waitforjob(jp); 864 INTON; 865 } else if (mode == 2) { 866 backcmd->fd = pip[0]; 867 close(pip[1]); 868 backcmd->jp = jp; 869 } 870 871out: 872 if (lastarg) 873 setvar("_", lastarg, 0); 874 popstackmark(&smark); 875} 876 877 878 879/* 880 * Search for a command. This is called before we fork so that the 881 * location of the command will be available in the parent as well as 882 * the child. The check for "goodname" is an overly conservative 883 * check that the name will not be subject to expansion. 884 */ 885 886STATIC void 887prehash(n) 888 union node *n; 889{ 890 struct cmdentry entry; 891 892 if (n->type == NCMD && n->ncmd.args) 893 if (goodname(n->ncmd.args->narg.text)) 894 find_command(n->ncmd.args->narg.text, &entry, 0, 895 pathval()); 896} 897 898 899 900/* 901 * Builtin commands. Builtin commands whose functions are closely 902 * tied to evaluation are implemented here. 903 */ 904 905/* 906 * No command given, or a bltin command with no arguments. Set the 907 * specified variables. 908 */ 909 910int 911bltincmd(argc, argv) 912 int argc __unused; 913 char **argv __unused; 914{ 915 listsetvar(cmdenviron); 916 /* 917 * Preserve exitstatus of a previous possible redirection 918 * as POSIX mandates 919 */ 920 return exitstatus; 921} 922 923 924/* 925 * Handle break and continue commands. Break, continue, and return are 926 * all handled by setting the evalskip flag. The evaluation routines 927 * above all check this flag, and if it is set they start skipping 928 * commands rather than executing them. The variable skipcount is 929 * the number of loops to break/continue, or the number of function 930 * levels to return. (The latter is always 1.) It should probably 931 * be an error to break out of more loops than exist, but it isn't 932 * in the standard shell so we don't make it one here. 933 */ 934 935int 936breakcmd(argc, argv) 937 int argc; 938 char **argv; 939{ 940 int n = argc > 1 ? number(argv[1]) : 1; 941 942 if (n > loopnest) 943 n = loopnest; 944 if (n > 0) { 945 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 946 skipcount = n; 947 } 948 return 0; 949} 950 951 952/* 953 * The return command. 954 */ 955 956int 957returncmd(argc, argv) 958 int argc; 959 char **argv; 960{ 961 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 962 963 if (funcnest) { 964 evalskip = SKIPFUNC; 965 skipcount = 1; 966 } else { 967 /* skip the rest of the file */ 968 evalskip = SKIPFILE; 969 skipcount = 1; 970 } 971 return ret; 972} 973 974 975int 976falsecmd(argc, argv) 977 int argc __unused; 978 char **argv __unused; 979{ 980 return 1; 981} 982 983 984int 985truecmd(argc, argv) 986 int argc __unused; 987 char **argv __unused; 988{ 989 return 0; 990} 991 992 993int 994execcmd(argc, argv) 995 int argc; 996 char **argv; 997{ 998 if (argc > 1) { 999 struct strlist *sp; 1000 1001 iflag = 0; /* exit on error */ 1002 mflag = 0; 1003 optschanged(); 1004 for (sp = cmdenviron; sp ; sp = sp->next) 1005 setvareq(sp->text, VEXPORT|VSTACK); 1006 shellexec(argv + 1, environment(), pathval(), 0); 1007 1008 } 1009 return 0; 1010} 1011