1 /* $NetBSD: eval.c,v 1.20 1995/03/31 21:58:09 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 8.1 (Berkeley) 5/31/93"; 42 #else 43 static char rcsid[] = "$NetBSD: eval.c,v 1.20 1995/03/31 21:58:09 christos Exp $"; 44 #endif 45 #endif /* not lint */ 46 47 /* 48 * Evaluate a command. 49 */ 50 51 #include "shell.h" 52 #include "nodes.h" 53 #include "syntax.h" 54 #include "expand.h" 55 #include "parser.h" 56 #include "jobs.h" 57 #include "eval.h" 58 #include "builtins.h" 59 #include "options.h" 60 #include "exec.h" 61 #include "redir.h" 62 #include "input.h" 63 #include "output.h" 64 #include "trap.h" 65 #include "var.h" 66 #include "memalloc.h" 67 #include "error.h" 68 #include "mystring.h" 69 #ifndef NO_HISTORY 70 #include "myhistedit.h" 71 #endif 72 #include "extern.h" 73 #include <signal.h> 74 #include <unistd.h> 75 76 77 /* flags in argument to evaltree */ 78 #define EV_EXIT 01 /* exit after evaluating tree */ 79 #define EV_TESTED 02 /* exit status is checked; ignore -e flag */ 80 #define EV_BACKCMD 04 /* command executing within back quotes */ 81 82 83 /* reasons for skipping commands (see comment on breakcmd routine) */ 84 #define SKIPBREAK 1 85 #define SKIPCONT 2 86 #define SKIPFUNC 3 87 88 MKINIT int evalskip; /* set if we are skipping commands */ 89 STATIC int skipcount; /* number of levels to skip */ 90 MKINIT int loopnest; /* current loop nesting level */ 91 int funcnest; /* depth of function calls */ 92 93 94 char *commandname; 95 struct strlist *cmdenviron; 96 int exitstatus; /* exit status of last command */ 97 98 99 #ifdef __STDC__ 100 STATIC void evalloop(union node *); 101 STATIC void evalfor(union node *); 102 STATIC void evalcase(union node *, int); 103 STATIC void evalsubshell(union node *, int); 104 STATIC void expredir(union node *); 105 STATIC void evalpipe(union node *); 106 STATIC void evalcommand(union node *, int, struct backcmd *); 107 STATIC void prehash(union node *); 108 #else 109 STATIC void evalloop(); 110 STATIC void evalfor(); 111 STATIC void evalcase(); 112 STATIC void evalsubshell(); 113 STATIC void expredir(); 114 STATIC void evalpipe(); 115 STATIC void evalcommand(); 116 STATIC void prehash(); 117 #endif 118 119 120 121 /* 122 * Called to reset things after an exception. 123 */ 124 125 #ifdef mkinit 126 INCLUDE "eval.h" 127 128 RESET { 129 evalskip = 0; 130 loopnest = 0; 131 funcnest = 0; 132 } 133 134 SHELLPROC { 135 exitstatus = 0; 136 } 137 #endif 138 139 140 141 /* 142 * The eval commmand. 143 */ 144 145 int 146 evalcmd(argc, argv) 147 int argc; 148 char **argv; 149 { 150 char *p; 151 char *concat; 152 char **ap; 153 154 if (argc > 1) { 155 p = argv[1]; 156 if (argc > 2) { 157 STARTSTACKSTR(concat); 158 ap = argv + 2; 159 for (;;) { 160 while (*p) 161 STPUTC(*p++, concat); 162 if ((p = *ap++) == NULL) 163 break; 164 STPUTC(' ', concat); 165 } 166 STPUTC('\0', concat); 167 p = grabstackstr(concat); 168 } 169 evalstring(p); 170 } 171 return exitstatus; 172 } 173 174 175 /* 176 * Execute a command or commands contained in a string. 177 */ 178 179 void 180 evalstring(s) 181 char *s; 182 { 183 union node *n; 184 struct stackmark smark; 185 186 setstackmark(&smark); 187 setinputstring(s, 1); 188 while ((n = parsecmd(0)) != NEOF) { 189 evaltree(n, 0); 190 popstackmark(&smark); 191 } 192 popfile(); 193 popstackmark(&smark); 194 } 195 196 197 198 /* 199 * Evaluate a parse tree. The value is left in the global variable 200 * exitstatus. 201 */ 202 203 void 204 evaltree(n, flags) 205 union node *n; 206 int flags; 207 { 208 if (n == NULL) { 209 TRACE(("evaltree(NULL) called\n")); 210 exitstatus = 0; 211 goto out; 212 } 213 #ifndef NO_HISTORY 214 displayhist = 1; /* show history substitutions done with fc */ 215 #endif 216 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type)); 217 switch (n->type) { 218 case NSEMI: 219 evaltree(n->nbinary.ch1, 0); 220 if (evalskip) 221 goto out; 222 evaltree(n->nbinary.ch2, flags); 223 break; 224 case NAND: 225 evaltree(n->nbinary.ch1, EV_TESTED); 226 if (evalskip || exitstatus != 0) 227 goto out; 228 evaltree(n->nbinary.ch2, flags); 229 break; 230 case NOR: 231 evaltree(n->nbinary.ch1, EV_TESTED); 232 if (evalskip || exitstatus == 0) 233 goto out; 234 evaltree(n->nbinary.ch2, flags); 235 break; 236 case NREDIR: 237 expredir(n->nredir.redirect); 238 redirect(n->nredir.redirect, REDIR_PUSH); 239 evaltree(n->nredir.n, flags); 240 popredir(); 241 break; 242 case NSUBSHELL: 243 evalsubshell(n, flags); 244 break; 245 case NBACKGND: 246 evalsubshell(n, flags); 247 break; 248 case NIF: { 249 int status = 0; 250 251 evaltree(n->nif.test, EV_TESTED); 252 if (evalskip) 253 goto out; 254 if (exitstatus == 0) { 255 evaltree(n->nif.ifpart, flags); 256 status = exitstatus; 257 } else if (n->nif.elsepart) { 258 evaltree(n->nif.elsepart, flags); 259 status = exitstatus; 260 } 261 exitstatus = status; 262 break; 263 } 264 case NWHILE: 265 case NUNTIL: 266 evalloop(n); 267 break; 268 case NFOR: 269 evalfor(n); 270 break; 271 case NCASE: 272 evalcase(n, flags); 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 exitstatus = !exitstatus; 281 break; 282 283 case NPIPE: 284 evalpipe(n); 285 break; 286 case NCMD: 287 evalcommand(n, flags, (struct backcmd *)NULL); 288 break; 289 default: 290 out1fmt("Node type = %d\n", n->type); 291 flushout(&output); 292 break; 293 } 294 out: 295 if (pendingsigs) 296 dotrap(); 297 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 298 exitshell(exitstatus); 299 } 300 301 302 STATIC void 303 evalloop(n) 304 union node *n; 305 { 306 int status; 307 308 loopnest++; 309 status = 0; 310 for (;;) { 311 evaltree(n->nbinary.ch1, EV_TESTED); 312 if (evalskip) { 313 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 314 evalskip = 0; 315 continue; 316 } 317 if (evalskip == SKIPBREAK && --skipcount <= 0) 318 evalskip = 0; 319 break; 320 } 321 if (n->type == NWHILE) { 322 if (exitstatus != 0) 323 break; 324 } else { 325 if (exitstatus == 0) 326 break; 327 } 328 evaltree(n->nbinary.ch2, 0); 329 status = exitstatus; 330 if (evalskip) 331 goto skipping; 332 } 333 loopnest--; 334 exitstatus = status; 335 } 336 337 338 339 STATIC void 340 evalfor(n) 341 union node *n; 342 { 343 struct arglist arglist; 344 union node *argp; 345 struct strlist *sp; 346 struct stackmark smark; 347 348 setstackmark(&smark); 349 arglist.lastp = &arglist.list; 350 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 351 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 352 if (evalskip) 353 goto out; 354 } 355 *arglist.lastp = NULL; 356 357 exitstatus = 0; 358 loopnest++; 359 for (sp = arglist.list ; sp ; sp = sp->next) { 360 setvar(n->nfor.var, sp->text, 0); 361 evaltree(n->nfor.body, 0); 362 if (evalskip) { 363 if (evalskip == SKIPCONT && --skipcount <= 0) { 364 evalskip = 0; 365 continue; 366 } 367 if (evalskip == SKIPBREAK && --skipcount <= 0) 368 evalskip = 0; 369 break; 370 } 371 } 372 loopnest--; 373 out: 374 popstackmark(&smark); 375 } 376 377 378 379 STATIC void 380 evalcase(n, flags) 381 union node *n; 382 int flags; 383 { 384 union node *cp; 385 union node *patp; 386 struct arglist arglist; 387 struct stackmark smark; 388 389 setstackmark(&smark); 390 arglist.lastp = &arglist.list; 391 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 392 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 393 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 394 if (casematch(patp, arglist.list->text)) { 395 if (evalskip == 0) { 396 evaltree(cp->nclist.body, flags); 397 } 398 goto out; 399 } 400 } 401 } 402 out: 403 popstackmark(&smark); 404 } 405 406 407 408 /* 409 * Kick off a subshell to evaluate a tree. 410 */ 411 412 STATIC void 413 evalsubshell(n, flags) 414 union node *n; 415 int flags; 416 { 417 struct job *jp; 418 int backgnd = (n->type == NBACKGND); 419 420 expredir(n->nredir.redirect); 421 jp = makejob(n, 1); 422 if (forkshell(jp, n, backgnd) == 0) { 423 if (backgnd) 424 flags &=~ EV_TESTED; 425 redirect(n->nredir.redirect, 0); 426 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 427 } 428 if (! backgnd) { 429 INTOFF; 430 exitstatus = waitforjob(jp); 431 INTON; 432 } 433 } 434 435 436 437 /* 438 * Compute the names of the files in a redirection list. 439 */ 440 441 STATIC void 442 expredir(n) 443 union node *n; 444 { 445 register union node *redir; 446 447 for (redir = n ; redir ; redir = redir->nfile.next) { 448 struct arglist fn; 449 fn.lastp = &fn.list; 450 switch (redir->type) { 451 case NFROM: 452 case NTO: 453 case NAPPEND: 454 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 455 redir->nfile.expfname = fn.list->text; 456 break; 457 case NFROMFD: 458 case NTOFD: 459 if (redir->ndup.vname) { 460 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 461 fixredir(redir, fn.list->text, 1); 462 } 463 break; 464 } 465 } 466 } 467 468 469 470 /* 471 * Evaluate a pipeline. All the processes in the pipeline are children 472 * of the process creating the pipeline. (This differs from some versions 473 * of the shell, which make the last process in a pipeline the parent 474 * of all the rest.) 475 */ 476 477 STATIC void 478 evalpipe(n) 479 union node *n; 480 { 481 struct job *jp; 482 struct nodelist *lp; 483 int pipelen; 484 int prevfd; 485 int pip[2]; 486 487 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 488 pipelen = 0; 489 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 490 pipelen++; 491 INTOFF; 492 jp = makejob(n, pipelen); 493 prevfd = -1; 494 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 495 prehash(lp->n); 496 pip[1] = -1; 497 if (lp->next) { 498 if (pipe(pip) < 0) { 499 close(prevfd); 500 error("Pipe call failed"); 501 } 502 } 503 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 504 INTON; 505 if (prevfd > 0) { 506 close(0); 507 copyfd(prevfd, 0); 508 close(prevfd); 509 } 510 if (pip[1] >= 0) { 511 close(pip[0]); 512 if (pip[1] != 1) { 513 close(1); 514 copyfd(pip[1], 1); 515 close(pip[1]); 516 } 517 } 518 evaltree(lp->n, EV_EXIT); 519 } 520 if (prevfd >= 0) 521 close(prevfd); 522 prevfd = pip[0]; 523 close(pip[1]); 524 } 525 INTON; 526 if (n->npipe.backgnd == 0) { 527 INTOFF; 528 exitstatus = waitforjob(jp); 529 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 530 INTON; 531 } 532 } 533 534 535 536 /* 537 * Execute a command inside back quotes. If it's a builtin command, we 538 * want to save its output in a block obtained from malloc. Otherwise 539 * we fork off a subprocess and get the output of the command via a pipe. 540 * Should be called with interrupts off. 541 */ 542 543 void 544 evalbackcmd(n, result) 545 union node *n; 546 struct backcmd *result; 547 { 548 int pip[2]; 549 struct job *jp; 550 struct stackmark smark; /* unnecessary */ 551 552 setstackmark(&smark); 553 result->fd = -1; 554 result->buf = NULL; 555 result->nleft = 0; 556 result->jp = NULL; 557 exitstatus = 0; 558 if (n == NULL) 559 goto out; 560 if (n->type == NCMD) { 561 evalcommand(n, EV_BACKCMD, result); 562 } else { 563 if (pipe(pip) < 0) 564 error("Pipe call failed"); 565 jp = makejob(n, 1); 566 if (forkshell(jp, n, FORK_NOJOB) == 0) { 567 FORCEINTON; 568 close(pip[0]); 569 if (pip[1] != 1) { 570 close(1); 571 copyfd(pip[1], 1); 572 close(pip[1]); 573 } 574 evaltree(n, EV_EXIT); 575 } 576 close(pip[1]); 577 result->fd = pip[0]; 578 result->jp = jp; 579 } 580 out: 581 popstackmark(&smark); 582 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 583 result->fd, result->buf, result->nleft, result->jp)); 584 } 585 586 587 588 /* 589 * Execute a simple command. 590 */ 591 592 STATIC void 593 evalcommand(cmd, flags, backcmd) 594 union node *cmd; 595 int flags; 596 struct backcmd *backcmd; 597 { 598 struct stackmark smark; 599 union node *argp; 600 struct arglist arglist; 601 struct arglist varlist; 602 char **argv; 603 int argc; 604 char **envp; 605 int varflag; 606 struct strlist *sp; 607 int mode; 608 int pip[2]; 609 struct cmdentry cmdentry; 610 struct job *jp; 611 struct jmploc jmploc; 612 struct jmploc *volatile savehandler; 613 char *volatile savecmdname; 614 volatile struct shparam saveparam; 615 struct localvar *volatile savelocalvars; 616 volatile int e; 617 char *lastarg; 618 619 /* First expand the arguments. */ 620 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 621 setstackmark(&smark); 622 arglist.lastp = &arglist.list; 623 varlist.lastp = &varlist.list; 624 varflag = 1; 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 find_command(argv[0], &cmdentry, 1); 678 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 679 exitstatus = 2; 680 flushout(&errout); 681 return; 682 } 683 /* implement the bltin builtin here */ 684 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 685 for (;;) { 686 argv++; 687 if (--argc == 0) 688 break; 689 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 690 outfmt(&errout, "%s: not found\n", *argv); 691 exitstatus = 2; 692 flushout(&errout); 693 return; 694 } 695 if (cmdentry.u.index != BLTINCMD) 696 break; 697 } 698 } 699 } 700 701 /* Fork off a child process if necessary. */ 702 if (cmd->ncmd.backgnd 703 || cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0 704 || (flags & EV_BACKCMD) != 0 705 && (cmdentry.cmdtype != CMDBUILTIN 706 || cmdentry.u.index == DOTCMD 707 || cmdentry.u.index == EVALCMD)) { 708 jp = makejob(cmd, 1); 709 mode = cmd->ncmd.backgnd; 710 if (flags & EV_BACKCMD) { 711 mode = FORK_NOJOB; 712 if (pipe(pip) < 0) 713 error("Pipe call failed"); 714 } 715 if (forkshell(jp, cmd, mode) != 0) 716 goto parent; /* at end of routine */ 717 if (flags & EV_BACKCMD) { 718 FORCEINTON; 719 close(pip[0]); 720 if (pip[1] != 1) { 721 close(1); 722 copyfd(pip[1], 1); 723 close(pip[1]); 724 } 725 } 726 flags |= EV_EXIT; 727 } 728 729 /* This is the child process if a fork occurred. */ 730 /* Execute the command. */ 731 if (cmdentry.cmdtype == CMDFUNCTION) { 732 trputs("Shell function: "); trargs(argv); 733 redirect(cmd->ncmd.redirect, REDIR_PUSH); 734 saveparam = shellparam; 735 shellparam.malloc = 0; 736 shellparam.nparam = argc - 1; 737 shellparam.p = argv + 1; 738 shellparam.optnext = NULL; 739 INTOFF; 740 savelocalvars = localvars; 741 localvars = NULL; 742 INTON; 743 if (setjmp(jmploc.loc)) { 744 if (exception == EXSHELLPROC) 745 freeparam((struct shparam *)&saveparam); 746 else { 747 freeparam(&shellparam); 748 shellparam = saveparam; 749 } 750 poplocalvars(); 751 localvars = savelocalvars; 752 handler = savehandler; 753 longjmp(handler->loc, 1); 754 } 755 savehandler = handler; 756 handler = &jmploc; 757 for (sp = varlist.list ; sp ; sp = sp->next) 758 mklocal(sp->text); 759 funcnest++; 760 evaltree(cmdentry.u.func, 0); 761 funcnest--; 762 INTOFF; 763 poplocalvars(); 764 localvars = savelocalvars; 765 freeparam(&shellparam); 766 shellparam = saveparam; 767 handler = savehandler; 768 popredir(); 769 INTON; 770 if (evalskip == SKIPFUNC) { 771 evalskip = 0; 772 skipcount = 0; 773 } 774 if (flags & EV_EXIT) 775 exitshell(exitstatus); 776 } else if (cmdentry.cmdtype == CMDBUILTIN) { 777 trputs("builtin command: "); trargs(argv); 778 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 779 if (flags == EV_BACKCMD) { 780 memout.nleft = 0; 781 memout.nextc = memout.buf; 782 memout.bufsize = 64; 783 mode |= REDIR_BACKQ; 784 } 785 redirect(cmd->ncmd.redirect, mode); 786 savecmdname = commandname; 787 cmdenviron = varlist.list; 788 e = -1; 789 if (setjmp(jmploc.loc)) { 790 e = exception; 791 exitstatus = (e == EXINT)? SIGINT+128 : 2; 792 goto cmddone; 793 } 794 savehandler = handler; 795 handler = &jmploc; 796 commandname = argv[0]; 797 argptr = argv + 1; 798 optptr = NULL; /* initialize nextopt */ 799 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 800 flushall(); 801 cmddone: 802 out1 = &output; 803 out2 = &errout; 804 freestdout(); 805 if (e != EXSHELLPROC) { 806 commandname = savecmdname; 807 if (flags & EV_EXIT) { 808 exitshell(exitstatus); 809 } 810 } 811 handler = savehandler; 812 if (e != -1) { 813 if (e != EXERROR || cmdentry.u.index == BLTINCMD 814 || cmdentry.u.index == DOTCMD 815 || cmdentry.u.index == EVALCMD 816 #ifndef NO_HISTORY 817 || cmdentry.u.index == HISTCMD 818 #endif 819 || cmdentry.u.index == EXECCMD) 820 exraise(e); 821 FORCEINTON; 822 } 823 if (cmdentry.u.index != EXECCMD) 824 popredir(); 825 if (flags == EV_BACKCMD) { 826 backcmd->buf = memout.buf; 827 backcmd->nleft = memout.nextc - memout.buf; 828 memout.buf = NULL; 829 } 830 } else { 831 trputs("normal command: "); trargs(argv); 832 clearredir(); 833 redirect(cmd->ncmd.redirect, 0); 834 for (sp = varlist.list ; sp ; sp = sp->next) 835 setvareq(sp->text, VEXPORT|VSTACK); 836 envp = environment(); 837 shellexec(argv, envp, pathval(), cmdentry.u.index); 838 /*NOTREACHED*/ 839 } 840 goto out; 841 842 parent: /* parent process gets here (if we forked) */ 843 if (mode == 0) { /* argument to fork */ 844 INTOFF; 845 exitstatus = waitforjob(jp); 846 INTON; 847 } else if (mode == 2) { 848 backcmd->fd = pip[0]; 849 close(pip[1]); 850 backcmd->jp = jp; 851 } 852 853 out: 854 if (lastarg) 855 setvar("_", lastarg, 0); 856 popstackmark(&smark); 857 } 858 859 860 861 /* 862 * Search for a command. This is called before we fork so that the 863 * location of the command will be available in the parent as well as 864 * the child. The check for "goodname" is an overly conservative 865 * check that the name will not be subject to expansion. 866 */ 867 868 STATIC void 869 prehash(n) 870 union node *n; 871 { 872 struct cmdentry entry; 873 874 if (n->type == NCMD && n->ncmd.args) 875 if (goodname(n->ncmd.args->narg.text)) 876 find_command(n->ncmd.args->narg.text, &entry, 0); 877 } 878 879 880 881 /* 882 * Builtin commands. Builtin commands whose functions are closely 883 * tied to evaluation are implemented here. 884 */ 885 886 /* 887 * No command given, or a bltin command with no arguments. Set the 888 * specified variables. 889 */ 890 891 int 892 bltincmd(argc, argv) 893 int argc; 894 char **argv; 895 { 896 listsetvar(cmdenviron); 897 return 0; 898 } 899 900 901 /* 902 * Handle break and continue commands. Break, continue, and return are 903 * all handled by setting the evalskip flag. The evaluation routines 904 * above all check this flag, and if it is set they start skipping 905 * commands rather than executing them. The variable skipcount is 906 * the number of loops to break/continue, or the number of function 907 * levels to return. (The latter is always 1.) It should probably 908 * be an error to break out of more loops than exist, but it isn't 909 * in the standard shell so we don't make it one here. 910 */ 911 912 int 913 breakcmd(argc, argv) 914 int argc; 915 char **argv; 916 { 917 int n; 918 919 n = 1; 920 if (argc > 1) 921 n = number(argv[1]); 922 if (n > loopnest) 923 n = loopnest; 924 if (n > 0) { 925 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 926 skipcount = n; 927 } 928 return 0; 929 } 930 931 932 /* 933 * The return command. 934 */ 935 936 int 937 returncmd(argc, argv) 938 int argc; 939 char **argv; 940 { 941 int ret; 942 943 ret = exitstatus; 944 if (argc > 1) 945 ret = number(argv[1]); 946 if (funcnest) { 947 evalskip = SKIPFUNC; 948 skipcount = 1; 949 } 950 return ret; 951 } 952 953 954 int 955 falsecmd(argc, argv) 956 int argc; 957 char **argv; 958 { 959 return 1; 960 } 961 962 963 int 964 truecmd(argc, argv) 965 int argc; 966 char **argv; 967 { 968 return 0; 969 } 970 971 972 int 973 execcmd(argc, argv) 974 int argc; 975 char **argv; 976 { 977 if (argc > 1) { 978 struct strlist *sp; 979 980 iflag = 0; /* exit on error */ 981 mflag = 0; 982 optschanged(); 983 for (sp = cmdenviron; sp ; sp = sp->next) 984 setvareq(sp->text, VEXPORT|VSTACK); 985 shellexec(argv + 1, environment(), pathval(), 0); 986 987 } 988 return 0; 989 } 990