1 /* $NetBSD: eval.c,v 1.33 1996/11/09 01:04:07 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 #ifndef lint 40 #if 0 41 static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 42 #else 43 static char sccsid[] = "$NetBSD: eval.c,v 1.33 1996/11/09 01:04:07 christos Exp $"; 44 #endif 45 #endif /* not lint */ 46 47 #include <signal.h> 48 #include <unistd.h> 49 50 /* 51 * Evaluate a command. 52 */ 53 54 #include "shell.h" 55 #include "nodes.h" 56 #include "syntax.h" 57 #include "expand.h" 58 #include "parser.h" 59 #include "jobs.h" 60 #include "eval.h" 61 #include "builtins.h" 62 #include "options.h" 63 #include "exec.h" 64 #include "redir.h" 65 #include "input.h" 66 #include "output.h" 67 #include "trap.h" 68 #include "var.h" 69 #include "memalloc.h" 70 #include "error.h" 71 #include "show.h" 72 #include "mystring.h" 73 #ifndef NO_HISTORY 74 #include "myhistedit.h" 75 #endif 76 77 78 /* flags in argument to evaltree */ 79 #define EV_EXIT 01 /* exit after evaluating tree */ 80 #define EV_TESTED 02 /* exit status is checked; ignore -e flag */ 81 #define EV_BACKCMD 04 /* command executing within back quotes */ 82 83 MKINIT int evalskip; /* set if we are skipping commands */ 84 STATIC int skipcount; /* number of levels to skip */ 85 MKINIT int loopnest; /* current loop nesting level */ 86 int funcnest; /* depth of function calls */ 87 88 89 char *commandname; 90 struct strlist *cmdenviron; 91 int exitstatus; /* exit status of last command */ 92 int oexitstatus; /* saved exit status */ 93 94 95 STATIC void evalloop __P((union node *)); 96 STATIC void evalfor __P((union node *)); 97 STATIC void evalcase __P((union node *, int)); 98 STATIC void evalsubshell __P((union node *, int)); 99 STATIC void expredir __P((union node *)); 100 STATIC void evalpipe __P((union node *)); 101 STATIC void evalcommand __P((union node *, int, struct backcmd *)); 102 STATIC void prehash __P((union node *)); 103 104 105 /* 106 * Called to reset things after an exception. 107 */ 108 109 #ifdef mkinit 110 INCLUDE "eval.h" 111 112 RESET { 113 evalskip = 0; 114 loopnest = 0; 115 funcnest = 0; 116 } 117 118 SHELLPROC { 119 exitstatus = 0; 120 } 121 #endif 122 123 124 125 /* 126 * The eval commmand. 127 */ 128 129 int 130 evalcmd(argc, argv) 131 int argc; 132 char **argv; 133 { 134 char *p; 135 char *concat; 136 char **ap; 137 138 if (argc > 1) { 139 p = argv[1]; 140 if (argc > 2) { 141 STARTSTACKSTR(concat); 142 ap = argv + 2; 143 for (;;) { 144 while (*p) 145 STPUTC(*p++, concat); 146 if ((p = *ap++) == NULL) 147 break; 148 STPUTC(' ', concat); 149 } 150 STPUTC('\0', concat); 151 p = grabstackstr(concat); 152 } 153 evalstring(p); 154 } 155 return exitstatus; 156 } 157 158 159 /* 160 * Execute a command or commands contained in a string. 161 */ 162 163 void 164 evalstring(s) 165 char *s; 166 { 167 union node *n; 168 struct stackmark smark; 169 170 setstackmark(&smark); 171 setinputstring(s, 1); 172 while ((n = parsecmd(0)) != NEOF) { 173 evaltree(n, 0); 174 popstackmark(&smark); 175 } 176 popfile(); 177 popstackmark(&smark); 178 } 179 180 181 182 /* 183 * Evaluate a parse tree. The value is left in the global variable 184 * exitstatus. 185 */ 186 187 void 188 evaltree(n, flags) 189 union node *n; 190 int flags; 191 { 192 if (n == NULL) { 193 TRACE(("evaltree(NULL) called\n")); 194 exitstatus = 0; 195 goto out; 196 } 197 #ifndef NO_HISTORY 198 displayhist = 1; /* show history substitutions done with fc */ 199 #endif 200 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type)); 201 switch (n->type) { 202 case NSEMI: 203 evaltree(n->nbinary.ch1, 0); 204 if (evalskip) 205 goto out; 206 evaltree(n->nbinary.ch2, flags); 207 break; 208 case NAND: 209 evaltree(n->nbinary.ch1, EV_TESTED); 210 if (evalskip || exitstatus != 0) { 211 /* don't bomb out on "set -e; false && true" */ 212 flags |= EV_TESTED; 213 goto out; 214 } 215 evaltree(n->nbinary.ch2, flags); 216 break; 217 case NOR: 218 evaltree(n->nbinary.ch1, EV_TESTED); 219 if (evalskip || exitstatus == 0) 220 goto out; 221 evaltree(n->nbinary.ch2, flags); 222 break; 223 case NREDIR: 224 expredir(n->nredir.redirect); 225 redirect(n->nredir.redirect, REDIR_PUSH); 226 evaltree(n->nredir.n, flags); 227 popredir(); 228 break; 229 case NSUBSHELL: 230 evalsubshell(n, flags); 231 break; 232 case NBACKGND: 233 evalsubshell(n, flags); 234 break; 235 case NIF: { 236 evaltree(n->nif.test, EV_TESTED); 237 if (evalskip) 238 goto out; 239 if (exitstatus == 0) 240 evaltree(n->nif.ifpart, flags); 241 else if (n->nif.elsepart) 242 evaltree(n->nif.elsepart, flags); 243 else 244 exitstatus = 0; 245 break; 246 } 247 case NWHILE: 248 case NUNTIL: 249 evalloop(n); 250 break; 251 case NFOR: 252 evalfor(n); 253 break; 254 case NCASE: 255 evalcase(n, flags); 256 break; 257 case NDEFUN: 258 defun(n->narg.text, n->narg.next); 259 exitstatus = 0; 260 break; 261 case NNOT: 262 evaltree(n->nnot.com, EV_TESTED); 263 exitstatus = !exitstatus; 264 break; 265 266 case NPIPE: 267 evalpipe(n); 268 break; 269 case NCMD: 270 evalcommand(n, flags, (struct backcmd *)NULL); 271 break; 272 default: 273 out1fmt("Node type = %d\n", n->type); 274 flushout(&output); 275 break; 276 } 277 out: 278 if (pendingsigs) 279 dotrap(); 280 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 281 exitshell(exitstatus); 282 } 283 284 285 STATIC void 286 evalloop(n) 287 union node *n; 288 { 289 int status; 290 291 loopnest++; 292 status = 0; 293 for (;;) { 294 evaltree(n->nbinary.ch1, EV_TESTED); 295 if (evalskip) { 296 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 297 evalskip = 0; 298 continue; 299 } 300 if (evalskip == SKIPBREAK && --skipcount <= 0) 301 evalskip = 0; 302 break; 303 } 304 if (n->type == NWHILE) { 305 if (exitstatus != 0) 306 break; 307 } else { 308 if (exitstatus == 0) 309 break; 310 } 311 evaltree(n->nbinary.ch2, 0); 312 status = exitstatus; 313 if (evalskip) 314 goto skipping; 315 } 316 loopnest--; 317 exitstatus = status; 318 } 319 320 321 322 STATIC void 323 evalfor(n) 324 union node *n; 325 { 326 struct arglist arglist; 327 union node *argp; 328 struct strlist *sp; 329 struct stackmark smark; 330 331 setstackmark(&smark); 332 arglist.lastp = &arglist.list; 333 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 334 oexitstatus = exitstatus; 335 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 336 if (evalskip) 337 goto out; 338 } 339 *arglist.lastp = NULL; 340 341 exitstatus = 0; 342 loopnest++; 343 for (sp = arglist.list ; sp ; sp = sp->next) { 344 setvar(n->nfor.var, sp->text, 0); 345 evaltree(n->nfor.body, 0); 346 if (evalskip) { 347 if (evalskip == SKIPCONT && --skipcount <= 0) { 348 evalskip = 0; 349 continue; 350 } 351 if (evalskip == SKIPBREAK && --skipcount <= 0) 352 evalskip = 0; 353 break; 354 } 355 } 356 loopnest--; 357 out: 358 popstackmark(&smark); 359 } 360 361 362 363 STATIC void 364 evalcase(n, flags) 365 union node *n; 366 int flags; 367 { 368 union node *cp; 369 union node *patp; 370 struct arglist arglist; 371 struct stackmark smark; 372 373 setstackmark(&smark); 374 arglist.lastp = &arglist.list; 375 oexitstatus = exitstatus; 376 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 377 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 378 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 379 if (casematch(patp, arglist.list->text)) { 380 if (evalskip == 0) { 381 evaltree(cp->nclist.body, flags); 382 } 383 goto out; 384 } 385 } 386 } 387 out: 388 popstackmark(&smark); 389 } 390 391 392 393 /* 394 * Kick off a subshell to evaluate a tree. 395 */ 396 397 STATIC void 398 evalsubshell(n, flags) 399 union node *n; 400 int flags; 401 { 402 struct job *jp; 403 int backgnd = (n->type == NBACKGND); 404 405 expredir(n->nredir.redirect); 406 jp = makejob(n, 1); 407 if (forkshell(jp, n, backgnd) == 0) { 408 if (backgnd) 409 flags &=~ EV_TESTED; 410 redirect(n->nredir.redirect, 0); 411 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 412 } 413 if (! backgnd) { 414 INTOFF; 415 exitstatus = waitforjob(jp); 416 INTON; 417 } 418 } 419 420 421 422 /* 423 * Compute the names of the files in a redirection list. 424 */ 425 426 STATIC void 427 expredir(n) 428 union node *n; 429 { 430 register union node *redir; 431 432 for (redir = n ; redir ; redir = redir->nfile.next) { 433 struct arglist fn; 434 fn.lastp = &fn.list; 435 oexitstatus = exitstatus; 436 switch (redir->type) { 437 case NFROM: 438 case NTO: 439 case NAPPEND: 440 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 441 redir->nfile.expfname = fn.list->text; 442 break; 443 case NFROMFD: 444 case NTOFD: 445 if (redir->ndup.vname) { 446 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 447 fixredir(redir, fn.list->text, 1); 448 } 449 break; 450 } 451 } 452 } 453 454 455 456 /* 457 * Evaluate a pipeline. All the processes in the pipeline are children 458 * of the process creating the pipeline. (This differs from some versions 459 * of the shell, which make the last process in a pipeline the parent 460 * of all the rest.) 461 */ 462 463 STATIC void 464 evalpipe(n) 465 union node *n; 466 { 467 struct job *jp; 468 struct nodelist *lp; 469 int pipelen; 470 int prevfd; 471 int pip[2]; 472 473 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 474 pipelen = 0; 475 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 476 pipelen++; 477 INTOFF; 478 jp = makejob(n, pipelen); 479 prevfd = -1; 480 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 481 prehash(lp->n); 482 pip[1] = -1; 483 if (lp->next) { 484 if (pipe(pip) < 0) { 485 close(prevfd); 486 error("Pipe call failed"); 487 } 488 } 489 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 490 INTON; 491 if (prevfd > 0) { 492 close(0); 493 copyfd(prevfd, 0); 494 close(prevfd); 495 } 496 if (pip[1] >= 0) { 497 close(pip[0]); 498 if (pip[1] != 1) { 499 close(1); 500 copyfd(pip[1], 1); 501 close(pip[1]); 502 } 503 } 504 evaltree(lp->n, EV_EXIT); 505 } 506 if (prevfd >= 0) 507 close(prevfd); 508 prevfd = pip[0]; 509 close(pip[1]); 510 } 511 INTON; 512 if (n->npipe.backgnd == 0) { 513 INTOFF; 514 exitstatus = waitforjob(jp); 515 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 516 INTON; 517 } 518 } 519 520 521 522 /* 523 * Execute a command inside back quotes. If it's a builtin command, we 524 * want to save its output in a block obtained from malloc. Otherwise 525 * we fork off a subprocess and get the output of the command via a pipe. 526 * Should be called with interrupts off. 527 */ 528 529 void 530 evalbackcmd(n, result) 531 union node *n; 532 struct backcmd *result; 533 { 534 int pip[2]; 535 struct job *jp; 536 struct stackmark smark; /* unnecessary */ 537 538 setstackmark(&smark); 539 result->fd = -1; 540 result->buf = NULL; 541 result->nleft = 0; 542 result->jp = NULL; 543 if (n == NULL) { 544 exitstatus = 0; 545 goto out; 546 } 547 if (n->type == NCMD) { 548 exitstatus = oexitstatus; 549 evalcommand(n, EV_BACKCMD, result); 550 } else { 551 exitstatus = 0; 552 if (pipe(pip) < 0) 553 error("Pipe call failed"); 554 jp = makejob(n, 1); 555 if (forkshell(jp, n, FORK_NOJOB) == 0) { 556 FORCEINTON; 557 close(pip[0]); 558 if (pip[1] != 1) { 559 close(1); 560 copyfd(pip[1], 1); 561 close(pip[1]); 562 } 563 evaltree(n, EV_EXIT); 564 } 565 close(pip[1]); 566 result->fd = pip[0]; 567 result->jp = jp; 568 } 569 out: 570 popstackmark(&smark); 571 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 572 result->fd, result->buf, result->nleft, result->jp)); 573 } 574 575 576 577 /* 578 * Execute a simple command. 579 */ 580 581 STATIC void 582 evalcommand(cmd, flags, backcmd) 583 union node *cmd; 584 int flags; 585 struct backcmd *backcmd; 586 { 587 struct stackmark smark; 588 union node *argp; 589 struct arglist arglist; 590 struct arglist varlist; 591 char **argv; 592 int argc; 593 char **envp; 594 int varflag; 595 struct strlist *sp; 596 int mode; 597 int pip[2]; 598 struct cmdentry cmdentry; 599 struct job *jp; 600 struct jmploc jmploc; 601 struct jmploc *volatile savehandler; 602 char *volatile savecmdname; 603 volatile struct shparam saveparam; 604 struct localvar *volatile savelocalvars; 605 volatile int e; 606 char *lastarg; 607 #if __GNUC__ 608 /* Avoid longjmp clobbering */ 609 (void) &argv; 610 (void) &argc; 611 (void) &lastarg; 612 (void) &flags; 613 #endif 614 615 /* First expand the arguments. */ 616 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 617 setstackmark(&smark); 618 arglist.lastp = &arglist.list; 619 varlist.lastp = &varlist.list; 620 varflag = 1; 621 oexitstatus = exitstatus; 622 exitstatus = 0; 623 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 624 char *p = argp->narg.text; 625 if (varflag && is_name(*p)) { 626 do { 627 p++; 628 } while (is_in_name(*p)); 629 if (*p == '=') { 630 expandarg(argp, &varlist, EXP_VARTILDE); 631 continue; 632 } 633 } 634 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 635 varflag = 0; 636 } 637 *arglist.lastp = NULL; 638 *varlist.lastp = NULL; 639 expredir(cmd->ncmd.redirect); 640 argc = 0; 641 for (sp = arglist.list ; sp ; sp = sp->next) 642 argc++; 643 argv = stalloc(sizeof (char *) * (argc + 1)); 644 645 for (sp = arglist.list ; sp ; sp = sp->next) { 646 TRACE(("evalcommand arg: %s\n", sp->text)); 647 *argv++ = sp->text; 648 } 649 *argv = NULL; 650 lastarg = NULL; 651 if (iflag && funcnest == 0 && argc > 0) 652 lastarg = argv[-1]; 653 argv -= argc; 654 655 /* Print the command if xflag is set. */ 656 if (xflag) { 657 outc('+', &errout); 658 for (sp = varlist.list ; sp ; sp = sp->next) { 659 outc(' ', &errout); 660 out2str(sp->text); 661 } 662 for (sp = arglist.list ; sp ; sp = sp->next) { 663 outc(' ', &errout); 664 out2str(sp->text); 665 } 666 outc('\n', &errout); 667 flushout(&errout); 668 } 669 670 /* Now locate the command. */ 671 if (argc == 0) { 672 cmdentry.cmdtype = CMDBUILTIN; 673 cmdentry.u.index = BLTINCMD; 674 } else { 675 static const char PATH[] = "PATH="; 676 char *path = pathval(); 677 678 /* 679 * Modify the command lookup path, if a PATH= assignment 680 * is present 681 */ 682 for (sp = varlist.list ; sp ; sp = sp->next) 683 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) 684 path = sp->text + sizeof(PATH) - 1; 685 686 find_command(argv[0], &cmdentry, 1, path); 687 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 688 exitstatus = 127; 689 flushout(&errout); 690 return; 691 } 692 /* implement the bltin builtin here */ 693 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 694 for (;;) { 695 argv++; 696 if (--argc == 0) 697 break; 698 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 699 outfmt(&errout, "%s: not found\n", *argv); 700 exitstatus = 127; 701 flushout(&errout); 702 return; 703 } 704 if (cmdentry.u.index != BLTINCMD) 705 break; 706 } 707 } 708 } 709 710 /* Fork off a child process if necessary. */ 711 if (cmd->ncmd.backgnd 712 || (cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0) 713 || ((flags & EV_BACKCMD) != 0 714 && (cmdentry.cmdtype != CMDBUILTIN 715 || cmdentry.u.index == DOTCMD 716 || cmdentry.u.index == EVALCMD))) { 717 jp = makejob(cmd, 1); 718 mode = cmd->ncmd.backgnd; 719 if (flags & EV_BACKCMD) { 720 mode = FORK_NOJOB; 721 if (pipe(pip) < 0) 722 error("Pipe call failed"); 723 } 724 if (forkshell(jp, cmd, mode) != 0) 725 goto parent; /* at end of routine */ 726 if (flags & EV_BACKCMD) { 727 FORCEINTON; 728 close(pip[0]); 729 if (pip[1] != 1) { 730 close(1); 731 copyfd(pip[1], 1); 732 close(pip[1]); 733 } 734 } 735 flags |= EV_EXIT; 736 } 737 738 /* This is the child process if a fork occurred. */ 739 /* Execute the command. */ 740 if (cmdentry.cmdtype == CMDFUNCTION) { 741 #ifdef DEBUG 742 trputs("Shell function: "); trargs(argv); 743 #endif 744 redirect(cmd->ncmd.redirect, REDIR_PUSH); 745 saveparam = shellparam; 746 shellparam.malloc = 0; 747 shellparam.reset = 1; 748 shellparam.nparam = argc - 1; 749 shellparam.p = argv + 1; 750 shellparam.optnext = NULL; 751 INTOFF; 752 savelocalvars = localvars; 753 localvars = NULL; 754 INTON; 755 if (setjmp(jmploc.loc)) { 756 if (exception == EXSHELLPROC) 757 freeparam((struct shparam *)&saveparam); 758 else { 759 freeparam(&shellparam); 760 shellparam = saveparam; 761 } 762 poplocalvars(); 763 localvars = savelocalvars; 764 handler = savehandler; 765 longjmp(handler->loc, 1); 766 } 767 savehandler = handler; 768 handler = &jmploc; 769 for (sp = varlist.list ; sp ; sp = sp->next) 770 mklocal(sp->text); 771 funcnest++; 772 evaltree(cmdentry.u.func, 0); 773 funcnest--; 774 INTOFF; 775 poplocalvars(); 776 localvars = savelocalvars; 777 freeparam(&shellparam); 778 shellparam = saveparam; 779 handler = savehandler; 780 popredir(); 781 INTON; 782 if (evalskip == SKIPFUNC) { 783 evalskip = 0; 784 skipcount = 0; 785 } 786 if (flags & EV_EXIT) 787 exitshell(exitstatus); 788 } else if (cmdentry.cmdtype == CMDBUILTIN) { 789 #ifdef DEBUG 790 trputs("builtin command: "); trargs(argv); 791 #endif 792 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 793 if (flags == EV_BACKCMD) { 794 memout.nleft = 0; 795 memout.nextc = memout.buf; 796 memout.bufsize = 64; 797 mode |= REDIR_BACKQ; 798 } 799 redirect(cmd->ncmd.redirect, mode); 800 savecmdname = commandname; 801 cmdenviron = varlist.list; 802 e = -1; 803 if (setjmp(jmploc.loc)) { 804 e = exception; 805 exitstatus = (e == EXINT)? SIGINT+128 : 2; 806 goto cmddone; 807 } 808 savehandler = handler; 809 handler = &jmploc; 810 commandname = argv[0]; 811 argptr = argv + 1; 812 optptr = NULL; /* initialize nextopt */ 813 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 814 flushall(); 815 cmddone: 816 out1 = &output; 817 out2 = &errout; 818 freestdout(); 819 if (e != EXSHELLPROC) { 820 commandname = savecmdname; 821 if (flags & EV_EXIT) { 822 exitshell(exitstatus); 823 } 824 } 825 handler = savehandler; 826 if (e != -1) { 827 if ((e != EXERROR && e != EXEXEC) 828 || cmdentry.u.index == BLTINCMD 829 || cmdentry.u.index == DOTCMD 830 || cmdentry.u.index == EVALCMD 831 #ifndef NO_HISTORY 832 || cmdentry.u.index == HISTCMD 833 #endif 834 || cmdentry.u.index == EXECCMD) 835 exraise(e); 836 FORCEINTON; 837 } 838 if (cmdentry.u.index != EXECCMD) 839 popredir(); 840 if (flags == EV_BACKCMD) { 841 backcmd->buf = memout.buf; 842 backcmd->nleft = memout.nextc - memout.buf; 843 memout.buf = NULL; 844 } 845 } else { 846 #ifdef DEBUG 847 trputs("normal command: "); trargs(argv); 848 #endif 849 clearredir(); 850 redirect(cmd->ncmd.redirect, 0); 851 for (sp = varlist.list ; sp ; sp = sp->next) 852 setvareq(sp->text, VEXPORT|VSTACK); 853 envp = environment(); 854 shellexec(argv, envp, pathval(), cmdentry.u.index); 855 /*NOTREACHED*/ 856 } 857 goto out; 858 859 parent: /* parent process gets here (if we forked) */ 860 if (mode == 0) { /* argument to fork */ 861 INTOFF; 862 exitstatus = waitforjob(jp); 863 INTON; 864 } else if (mode == 2) { 865 backcmd->fd = pip[0]; 866 close(pip[1]); 867 backcmd->jp = jp; 868 } 869 870 out: 871 if (lastarg) 872 setvar("_", lastarg, 0); 873 popstackmark(&smark); 874 } 875 876 877 878 /* 879 * Search for a command. This is called before we fork so that the 880 * location of the command will be available in the parent as well as 881 * the child. The check for "goodname" is an overly conservative 882 * check that the name will not be subject to expansion. 883 */ 884 885 STATIC void 886 prehash(n) 887 union node *n; 888 { 889 struct cmdentry entry; 890 891 if (n->type == NCMD && n->ncmd.args) 892 if (goodname(n->ncmd.args->narg.text)) 893 find_command(n->ncmd.args->narg.text, &entry, 0, 894 pathval()); 895 } 896 897 898 899 /* 900 * Builtin commands. Builtin commands whose functions are closely 901 * tied to evaluation are implemented here. 902 */ 903 904 /* 905 * No command given, or a bltin command with no arguments. Set the 906 * specified variables. 907 */ 908 909 int 910 bltincmd(argc, argv) 911 int argc; 912 char **argv; 913 { 914 listsetvar(cmdenviron); 915 /* 916 * Preserve exitstatus of a previous possible redirection 917 * as POSIX mandates 918 */ 919 return exitstatus; 920 } 921 922 923 /* 924 * Handle break and continue commands. Break, continue, and return are 925 * all handled by setting the evalskip flag. The evaluation routines 926 * above all check this flag, and if it is set they start skipping 927 * commands rather than executing them. The variable skipcount is 928 * the number of loops to break/continue, or the number of function 929 * levels to return. (The latter is always 1.) It should probably 930 * be an error to break out of more loops than exist, but it isn't 931 * in the standard shell so we don't make it one here. 932 */ 933 934 int 935 breakcmd(argc, argv) 936 int argc; 937 char **argv; 938 { 939 int n = argc > 1 ? number(argv[1]) : 1; 940 941 if (n > loopnest) 942 n = loopnest; 943 if (n > 0) { 944 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 945 skipcount = n; 946 } 947 return 0; 948 } 949 950 951 /* 952 * The return command. 953 */ 954 955 int 956 returncmd(argc, argv) 957 int argc; 958 char **argv; 959 { 960 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 961 962 if (funcnest) { 963 evalskip = SKIPFUNC; 964 skipcount = 1; 965 return ret; 966 } 967 else { 968 /* Do what ksh does; skip the rest of the file */ 969 evalskip = SKIPFILE; 970 skipcount = 1; 971 return ret; 972 } 973 } 974 975 976 int 977 falsecmd(argc, argv) 978 int argc; 979 char **argv; 980 { 981 return 1; 982 } 983 984 985 int 986 truecmd(argc, argv) 987 int argc; 988 char **argv; 989 { 990 return 0; 991 } 992 993 994 int 995 execcmd(argc, argv) 996 int argc; 997 char **argv; 998 { 999 if (argc > 1) { 1000 struct strlist *sp; 1001 1002 iflag = 0; /* exit on error */ 1003 mflag = 0; 1004 optschanged(); 1005 for (sp = cmdenviron; sp ; sp = sp->next) 1006 setvareq(sp->text, VEXPORT|VSTACK); 1007 shellexec(argv + 1, environment(), pathval(), 0); 1008 1009 } 1010 return 0; 1011 } 1012