1 /* $NetBSD: eval.c,v 1.45 1999/02/04 16:17:39 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Kenneth Almquist. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #ifndef lint 41 #if 0 42 static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 43 #else 44 __RCSID("$NetBSD: eval.c,v 1.45 1999/02/04 16:17:39 christos Exp $"); 45 #endif 46 #endif /* not lint */ 47 48 #include <signal.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 SMALL 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 MKINIT 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 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 __P((union node *)); 97 STATIC void evalfor __P((union node *)); 98 STATIC void evalcase __P((union node *, int)); 99 STATIC void evalsubshell __P((union node *, int)); 100 STATIC void expredir __P((union node *)); 101 STATIC void evalpipe __P((union node *)); 102 STATIC void evalcommand __P((union node *, int, struct backcmd *)); 103 STATIC void prehash __P((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 commmand. 128 */ 129 130 int 131 evalcmd(argc, argv) 132 int argc; 133 char **argv; 134 { 135 char *p; 136 char *concat; 137 char **ap; 138 139 if (argc > 1) { 140 p = argv[1]; 141 if (argc > 2) { 142 STARTSTACKSTR(concat); 143 ap = argv + 2; 144 for (;;) { 145 while (*p) 146 STPUTC(*p++, concat); 147 if ((p = *ap++) == NULL) 148 break; 149 STPUTC(' ', concat); 150 } 151 STPUTC('\0', concat); 152 p = grabstackstr(concat); 153 } 154 evalstring(p); 155 } 156 return exitstatus; 157 } 158 159 160 /* 161 * Execute a command or commands contained in a string. 162 */ 163 164 void 165 evalstring(s) 166 char *s; 167 { 168 union node *n; 169 struct stackmark smark; 170 171 setstackmark(&smark); 172 setinputstring(s, 1); 173 while ((n = parsecmd(0)) != NEOF) { 174 evaltree(n, 0); 175 popstackmark(&smark); 176 } 177 popfile(); 178 popstackmark(&smark); 179 } 180 181 182 183 /* 184 * Evaluate a parse tree. The value is left in the global variable 185 * exitstatus. 186 */ 187 188 void 189 evaltree(n, flags) 190 union node *n; 191 int flags; 192 { 193 if (n == NULL) { 194 TRACE(("evaltree(NULL) called\n")); 195 exitstatus = 0; 196 goto out; 197 } 198 #ifndef SMALL 199 displayhist = 1; /* show history substitutions done with fc */ 200 #endif 201 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type)); 202 switch (n->type) { 203 case NSEMI: 204 evaltree(n->nbinary.ch1, 0); 205 if (evalskip) 206 goto out; 207 evaltree(n->nbinary.ch2, flags); 208 break; 209 case NAND: 210 evaltree(n->nbinary.ch1, EV_TESTED); 211 if (evalskip || exitstatus != 0) { 212 /* don't bomb out on "set -e; false && true" */ 213 flags |= EV_TESTED; 214 goto out; 215 } 216 evaltree(n->nbinary.ch2, flags); 217 break; 218 case NOR: 219 evaltree(n->nbinary.ch1, EV_TESTED); 220 if (evalskip || exitstatus == 0) 221 goto out; 222 evaltree(n->nbinary.ch2, flags); 223 break; 224 case NREDIR: 225 expredir(n->nredir.redirect); 226 redirect(n->nredir.redirect, REDIR_PUSH); 227 evaltree(n->nredir.n, flags); 228 popredir(); 229 break; 230 case NSUBSHELL: 231 evalsubshell(n, flags); 232 break; 233 case NBACKGND: 234 evalsubshell(n, flags); 235 break; 236 case NIF: { 237 evaltree(n->nif.test, EV_TESTED); 238 if (evalskip) 239 goto out; 240 if (exitstatus == 0) 241 evaltree(n->nif.ifpart, flags); 242 else if (n->nif.elsepart) 243 evaltree(n->nif.elsepart, flags); 244 else 245 exitstatus = 0; 246 break; 247 } 248 case NWHILE: 249 case NUNTIL: 250 evalloop(n); 251 break; 252 case NFOR: 253 evalfor(n); 254 break; 255 case NCASE: 256 evalcase(n, flags); 257 break; 258 case NDEFUN: 259 defun(n->narg.text, n->narg.next); 260 exitstatus = 0; 261 break; 262 case NNOT: 263 evaltree(n->nnot.com, EV_TESTED); 264 exitstatus = !exitstatus; 265 break; 266 267 case NPIPE: 268 evalpipe(n); 269 break; 270 case NCMD: 271 evalcommand(n, flags, (struct backcmd *)NULL); 272 break; 273 default: 274 out1fmt("Node type = %d\n", n->type); 275 flushout(&output); 276 break; 277 } 278 out: 279 if (pendingsigs) 280 dotrap(); 281 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 282 exitshell(exitstatus); 283 } 284 285 286 STATIC void 287 evalloop(n) 288 union node *n; 289 { 290 int status; 291 292 loopnest++; 293 status = 0; 294 for (;;) { 295 evaltree(n->nbinary.ch1, EV_TESTED); 296 if (evalskip) { 297 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 298 evalskip = 0; 299 continue; 300 } 301 if (evalskip == SKIPBREAK && --skipcount <= 0) 302 evalskip = 0; 303 break; 304 } 305 if (n->type == NWHILE) { 306 if (exitstatus != 0) 307 break; 308 } else { 309 if (exitstatus == 0) 310 break; 311 } 312 evaltree(n->nbinary.ch2, 0); 313 status = exitstatus; 314 if (evalskip) 315 goto skipping; 316 } 317 loopnest--; 318 exitstatus = status; 319 } 320 321 322 323 STATIC void 324 evalfor(n) 325 union node *n; 326 { 327 struct arglist arglist; 328 union node *argp; 329 struct strlist *sp; 330 struct stackmark smark; 331 332 setstackmark(&smark); 333 arglist.lastp = &arglist.list; 334 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 335 oexitstatus = exitstatus; 336 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE | EXP_RECORD); 337 if (evalskip) 338 goto out; 339 } 340 *arglist.lastp = NULL; 341 342 exitstatus = 0; 343 loopnest++; 344 for (sp = arglist.list ; sp ; sp = sp->next) { 345 setvar(n->nfor.var, sp->text, 0); 346 evaltree(n->nfor.body, 0); 347 if (evalskip) { 348 if (evalskip == SKIPCONT && --skipcount <= 0) { 349 evalskip = 0; 350 continue; 351 } 352 if (evalskip == SKIPBREAK && --skipcount <= 0) 353 evalskip = 0; 354 break; 355 } 356 } 357 loopnest--; 358 out: 359 popstackmark(&smark); 360 } 361 362 363 364 STATIC void 365 evalcase(n, flags) 366 union node *n; 367 int flags; 368 { 369 union node *cp; 370 union node *patp; 371 struct arglist arglist; 372 struct stackmark smark; 373 374 setstackmark(&smark); 375 arglist.lastp = &arglist.list; 376 oexitstatus = exitstatus; 377 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 378 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 379 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 380 if (casematch(patp, arglist.list->text)) { 381 if (evalskip == 0) { 382 evaltree(cp->nclist.body, flags); 383 } 384 goto out; 385 } 386 } 387 } 388 out: 389 popstackmark(&smark); 390 } 391 392 393 394 /* 395 * Kick off a subshell to evaluate a tree. 396 */ 397 398 STATIC void 399 evalsubshell(n, flags) 400 union node *n; 401 int flags; 402 { 403 struct job *jp; 404 int backgnd = (n->type == NBACKGND); 405 406 expredir(n->nredir.redirect); 407 jp = makejob(n, 1); 408 if (forkshell(jp, n, backgnd) == 0) { 409 if (backgnd) 410 flags &=~ EV_TESTED; 411 redirect(n->nredir.redirect, 0); 412 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 413 } 414 if (! backgnd) { 415 INTOFF; 416 exitstatus = waitforjob(jp); 417 INTON; 418 } 419 } 420 421 422 423 /* 424 * Compute the names of the files in a redirection list. 425 */ 426 427 STATIC void 428 expredir(n) 429 union node *n; 430 { 431 union node *redir; 432 433 for (redir = n ; redir ; redir = redir->nfile.next) { 434 struct arglist fn; 435 fn.lastp = &fn.list; 436 oexitstatus = exitstatus; 437 switch (redir->type) { 438 case NFROMTO: 439 case NFROM: 440 case NTO: 441 case NAPPEND: 442 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 443 redir->nfile.expfname = fn.list->text; 444 break; 445 case NFROMFD: 446 case NTOFD: 447 if (redir->ndup.vname) { 448 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 449 fixredir(redir, fn.list->text, 1); 450 } 451 break; 452 } 453 } 454 } 455 456 457 458 /* 459 * Evaluate a pipeline. All the processes in the pipeline are children 460 * of the process creating the pipeline. (This differs from some versions 461 * of the shell, which make the last process in a pipeline the parent 462 * of all the rest.) 463 */ 464 465 STATIC void 466 evalpipe(n) 467 union node *n; 468 { 469 struct job *jp; 470 struct nodelist *lp; 471 int pipelen; 472 int prevfd; 473 int pip[2]; 474 475 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 476 pipelen = 0; 477 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 478 pipelen++; 479 INTOFF; 480 jp = makejob(n, pipelen); 481 prevfd = -1; 482 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 483 prehash(lp->n); 484 pip[1] = -1; 485 if (lp->next) { 486 if (pipe(pip) < 0) { 487 close(prevfd); 488 error("Pipe call failed"); 489 } 490 } 491 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 492 INTON; 493 if (prevfd > 0) { 494 close(0); 495 copyfd(prevfd, 0); 496 close(prevfd); 497 } 498 if (pip[1] >= 0) { 499 close(pip[0]); 500 if (pip[1] != 1) { 501 close(1); 502 copyfd(pip[1], 1); 503 close(pip[1]); 504 } 505 } 506 evaltree(lp->n, EV_EXIT); 507 } 508 if (prevfd >= 0) 509 close(prevfd); 510 prevfd = pip[0]; 511 close(pip[1]); 512 } 513 INTON; 514 if (n->npipe.backgnd == 0) { 515 INTOFF; 516 exitstatus = waitforjob(jp); 517 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 518 INTON; 519 } 520 } 521 522 523 524 /* 525 * Execute a command inside back quotes. If it's a builtin command, we 526 * want to save its output in a block obtained from malloc. Otherwise 527 * we fork off a subprocess and get the output of the command via a pipe. 528 * Should be called with interrupts off. 529 */ 530 531 void 532 evalbackcmd(n, result) 533 union node *n; 534 struct backcmd *result; 535 { 536 int pip[2]; 537 struct job *jp; 538 struct stackmark smark; /* unnecessary */ 539 540 setstackmark(&smark); 541 result->fd = -1; 542 result->buf = NULL; 543 result->nleft = 0; 544 result->jp = NULL; 545 if (n == NULL) { 546 exitstatus = 0; 547 goto out; 548 } 549 if (n->type == NCMD) { 550 exitstatus = oexitstatus; 551 evalcommand(n, EV_BACKCMD, result); 552 } else { 553 exitstatus = 0; 554 if (pipe(pip) < 0) 555 error("Pipe call failed"); 556 jp = makejob(n, 1); 557 if (forkshell(jp, n, FORK_NOJOB) == 0) { 558 FORCEINTON; 559 close(pip[0]); 560 if (pip[1] != 1) { 561 close(1); 562 copyfd(pip[1], 1); 563 close(pip[1]); 564 } 565 evaltree(n, EV_EXIT); 566 } 567 close(pip[1]); 568 result->fd = pip[0]; 569 result->jp = jp; 570 } 571 out: 572 popstackmark(&smark); 573 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 574 result->fd, result->buf, result->nleft, result->jp)); 575 } 576 577 578 579 /* 580 * Execute a simple command. 581 */ 582 583 STATIC void 584 evalcommand(cmd, flags, backcmd) 585 union node *cmd; 586 int flags; 587 struct backcmd *backcmd; 588 { 589 struct stackmark smark; 590 union node *argp; 591 struct arglist arglist; 592 struct arglist varlist; 593 char **argv; 594 int argc; 595 char **envp; 596 int varflag; 597 struct strlist *sp; 598 int mode; 599 int pip[2]; 600 struct cmdentry cmdentry; 601 struct job *jp; 602 struct jmploc jmploc; 603 struct jmploc *volatile savehandler; 604 char *volatile savecmdname; 605 volatile struct shparam saveparam; 606 struct localvar *volatile savelocalvars; 607 volatile int e; 608 char *lastarg; 609 #if __GNUC__ 610 /* Avoid longjmp clobbering */ 611 (void) &argv; 612 (void) &argc; 613 (void) &lastarg; 614 (void) &flags; 615 #endif 616 617 /* First expand the arguments. */ 618 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 619 setstackmark(&smark); 620 arglist.lastp = &arglist.list; 621 varlist.lastp = &varlist.list; 622 varflag = 1; 623 oexitstatus = exitstatus; 624 exitstatus = 0; 625 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 626 char *p = argp->narg.text; 627 if (varflag && is_name(*p)) { 628 do { 629 p++; 630 } while (is_in_name(*p)); 631 if (*p == '=') { 632 expandarg(argp, &varlist, EXP_VARTILDE); 633 continue; 634 } 635 } 636 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 637 varflag = 0; 638 } 639 *arglist.lastp = NULL; 640 *varlist.lastp = NULL; 641 expredir(cmd->ncmd.redirect); 642 argc = 0; 643 for (sp = arglist.list ; sp ; sp = sp->next) 644 argc++; 645 argv = stalloc(sizeof (char *) * (argc + 1)); 646 647 for (sp = arglist.list ; sp ; sp = sp->next) { 648 TRACE(("evalcommand arg: %s\n", sp->text)); 649 *argv++ = sp->text; 650 } 651 *argv = NULL; 652 lastarg = NULL; 653 if (iflag && funcnest == 0 && argc > 0) 654 lastarg = argv[-1]; 655 argv -= argc; 656 657 /* Print the command if xflag is set. */ 658 if (xflag) { 659 outc('+', &errout); 660 for (sp = varlist.list ; sp ; sp = sp->next) { 661 outc(' ', &errout); 662 out2str(sp->text); 663 } 664 for (sp = arglist.list ; sp ; sp = sp->next) { 665 outc(' ', &errout); 666 out2str(sp->text); 667 } 668 outc('\n', &errout); 669 flushout(&errout); 670 } 671 672 /* Now locate the command. */ 673 if (argc == 0) { 674 cmdentry.cmdtype = CMDBUILTIN; 675 cmdentry.u.index = BLTINCMD; 676 } else { 677 static const char PATH[] = "PATH="; 678 char *path = pathval(); 679 680 /* 681 * Modify the command lookup path, if a PATH= assignment 682 * is present 683 */ 684 for (sp = varlist.list ; sp ; sp = sp->next) 685 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) 686 path = sp->text + sizeof(PATH) - 1; 687 688 find_command(argv[0], &cmdentry, DO_ERR, path); 689 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 690 exitstatus = 127; 691 flushout(&errout); 692 return; 693 } 694 /* implement the bltin builtin here */ 695 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 696 for (;;) { 697 argv++; 698 if (--argc == 0) 699 break; 700 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 701 outfmt(&errout, "%s: not found\n", *argv); 702 exitstatus = 127; 703 flushout(&errout); 704 return; 705 } 706 if (cmdentry.u.index != BLTINCMD) 707 break; 708 } 709 } 710 } 711 712 /* Fork off a child process if necessary. */ 713 if (cmd->ncmd.backgnd 714 || (cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0) 715 || ((flags & EV_BACKCMD) != 0 716 && (cmdentry.cmdtype != CMDBUILTIN 717 || cmdentry.u.index == DOTCMD 718 || cmdentry.u.index == EVALCMD))) { 719 jp = makejob(cmd, 1); 720 mode = cmd->ncmd.backgnd; 721 if (flags & EV_BACKCMD) { 722 mode = FORK_NOJOB; 723 if (pipe(pip) < 0) 724 error("Pipe call failed"); 725 } 726 if (forkshell(jp, cmd, mode) != 0) 727 goto parent; /* at end of routine */ 728 if (flags & EV_BACKCMD) { 729 FORCEINTON; 730 close(pip[0]); 731 if (pip[1] != 1) { 732 close(1); 733 copyfd(pip[1], 1); 734 close(pip[1]); 735 } 736 } 737 flags |= EV_EXIT; 738 } 739 740 /* This is the child process if a fork occurred. */ 741 /* Execute the command. */ 742 if (cmdentry.cmdtype == CMDFUNCTION) { 743 #ifdef DEBUG 744 trputs("Shell function: "); trargs(argv); 745 #endif 746 redirect(cmd->ncmd.redirect, REDIR_PUSH); 747 saveparam = shellparam; 748 shellparam.malloc = 0; 749 shellparam.reset = 1; 750 shellparam.nparam = argc - 1; 751 shellparam.p = argv + 1; 752 shellparam.optnext = NULL; 753 INTOFF; 754 savelocalvars = localvars; 755 localvars = NULL; 756 INTON; 757 if (setjmp(jmploc.loc)) { 758 if (exception == EXSHELLPROC) 759 freeparam((struct shparam *)&saveparam); 760 else { 761 freeparam(&shellparam); 762 shellparam = saveparam; 763 } 764 poplocalvars(); 765 localvars = savelocalvars; 766 handler = savehandler; 767 longjmp(handler->loc, 1); 768 } 769 savehandler = handler; 770 handler = &jmploc; 771 for (sp = varlist.list ; sp ; sp = sp->next) 772 mklocal(sp->text); 773 funcnest++; 774 evaltree(cmdentry.u.func, 0); 775 funcnest--; 776 INTOFF; 777 poplocalvars(); 778 localvars = savelocalvars; 779 freeparam(&shellparam); 780 shellparam = saveparam; 781 handler = savehandler; 782 popredir(); 783 INTON; 784 if (evalskip == SKIPFUNC) { 785 evalskip = 0; 786 skipcount = 0; 787 } 788 if (flags & EV_EXIT) 789 exitshell(exitstatus); 790 } else if (cmdentry.cmdtype == CMDBUILTIN) { 791 #ifdef DEBUG 792 trputs("builtin command: "); trargs(argv); 793 #endif 794 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 795 if (flags == EV_BACKCMD) { 796 memout.nleft = 0; 797 memout.nextc = memout.buf; 798 memout.bufsize = 64; 799 mode |= REDIR_BACKQ; 800 } 801 redirect(cmd->ncmd.redirect, mode); 802 savecmdname = commandname; 803 cmdenviron = varlist.list; 804 e = -1; 805 if (setjmp(jmploc.loc)) { 806 e = exception; 807 exitstatus = (e == EXINT)? SIGINT+128 : 2; 808 goto cmddone; 809 } 810 savehandler = handler; 811 handler = &jmploc; 812 commandname = argv[0]; 813 argptr = argv + 1; 814 optptr = NULL; /* initialize nextopt */ 815 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 816 flushall(); 817 cmddone: 818 out1 = &output; 819 out2 = &errout; 820 freestdout(); 821 cmdenviron = NULL; 822 if (e != EXSHELLPROC) { 823 commandname = savecmdname; 824 if (flags & EV_EXIT) 825 exitshell(exitstatus); 826 } 827 handler = savehandler; 828 if (e != -1) { 829 if ((e != EXERROR && e != EXEXEC) 830 || cmdentry.u.index == BLTINCMD 831 || cmdentry.u.index == DOTCMD 832 || cmdentry.u.index == EVALCMD 833 #ifndef SMALL 834 || cmdentry.u.index == HISTCMD 835 #endif 836 || cmdentry.u.index == EXECCMD) 837 exraise(e); 838 FORCEINTON; 839 } 840 if (cmdentry.u.index != EXECCMD) 841 popredir(); 842 if (flags == EV_BACKCMD) { 843 backcmd->buf = memout.buf; 844 backcmd->nleft = memout.nextc - memout.buf; 845 memout.buf = NULL; 846 } 847 } else { 848 #ifdef DEBUG 849 trputs("normal command: "); trargs(argv); 850 #endif 851 clearredir(); 852 redirect(cmd->ncmd.redirect, 0); 853 for (sp = varlist.list ; sp ; sp = sp->next) 854 setvareq(sp->text, VEXPORT|VSTACK); 855 envp = environment(); 856 shellexec(argv, envp, pathval(), cmdentry.u.index); 857 } 858 goto out; 859 860 parent: /* 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 } 870 871 out: 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 */ 885 886 STATIC void 887 prehash(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 */ 909 910 int 911 bltincmd(argc, argv) 912 int argc; 913 char **argv; 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 */ 934 935 int 936 breakcmd(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 */ 955 956 int 957 returncmd(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 return ret; 967 } 968 else { 969 /* Do what ksh does; skip the rest of the file */ 970 evalskip = SKIPFILE; 971 skipcount = 1; 972 return ret; 973 } 974 } 975 976 977 int 978 falsecmd(argc, argv) 979 int argc; 980 char **argv; 981 { 982 return 1; 983 } 984 985 986 int 987 truecmd(argc, argv) 988 int argc; 989 char **argv; 990 { 991 return 0; 992 } 993 994 995 int 996 execcmd(argc, argv) 997 int argc; 998 char **argv; 999 { 1000 if (argc > 1) { 1001 struct strlist *sp; 1002 1003 iflag = 0; /* exit on error */ 1004 mflag = 0; 1005 optschanged(); 1006 for (sp = cmdenviron; sp ; sp = sp->next) 1007 setvareq(sp->text, VEXPORT|VSTACK); 1008 shellexec(argv + 1, environment(), pathval(), 0); 1009 } 1010 return 0; 1011 } 1012