1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * 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 /*static char sccsid[] = "from: @(#)eval.c 8.1 (Berkeley) 5/31/93";*/ 39 static char *rcsid = "$Id: eval.c,v 1.17 1994/12/05 19:07:37 cgd Exp $"; 40 #endif /* not lint */ 41 42 /* 43 * Evaluate a command. 44 */ 45 46 #include "shell.h" 47 #include "nodes.h" 48 #include "syntax.h" 49 #include "expand.h" 50 #include "parser.h" 51 #include "jobs.h" 52 #include "eval.h" 53 #include "builtins.h" 54 #include "options.h" 55 #include "exec.h" 56 #include "redir.h" 57 #include "input.h" 58 #include "output.h" 59 #include "trap.h" 60 #include "var.h" 61 #include "memalloc.h" 62 #include "error.h" 63 #include "mystring.h" 64 #ifndef NO_HISTORY 65 #include "myhistedit.h" 66 #endif 67 #include "extern.h" 68 #include <signal.h> 69 #include <unistd.h> 70 71 72 /* flags in argument to evaltree */ 73 #define EV_EXIT 01 /* exit after evaluating tree */ 74 #define EV_TESTED 02 /* exit status is checked; ignore -e flag */ 75 #define EV_BACKCMD 04 /* command executing within back quotes */ 76 77 78 /* reasons for skipping commands (see comment on breakcmd routine) */ 79 #define SKIPBREAK 1 80 #define SKIPCONT 2 81 #define SKIPFUNC 3 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 93 94 #ifdef __STDC__ 95 STATIC void evalloop(union node *); 96 STATIC void evalfor(union node *); 97 STATIC void evalcase(union node *, int); 98 STATIC void evalsubshell(union node *, int); 99 STATIC void expredir(union node *); 100 STATIC void evalpipe(union node *); 101 STATIC void evalcommand(union node *, int, struct backcmd *); 102 STATIC void prehash(union node *); 103 #else 104 STATIC void evalloop(); 105 STATIC void evalfor(); 106 STATIC void evalcase(); 107 STATIC void evalsubshell(); 108 STATIC void expredir(); 109 STATIC void evalpipe(); 110 STATIC void evalcommand(); 111 STATIC void prehash(); 112 #endif 113 114 115 116 /* 117 * Called to reset things after an exception. 118 */ 119 120 #ifdef mkinit 121 INCLUDE "eval.h" 122 123 RESET { 124 evalskip = 0; 125 loopnest = 0; 126 funcnest = 0; 127 } 128 129 SHELLPROC { 130 exitstatus = 0; 131 } 132 #endif 133 134 135 136 /* 137 * The eval commmand. 138 */ 139 140 int 141 evalcmd(argc, argv) 142 int argc; 143 char **argv; 144 { 145 char *p; 146 char *concat; 147 char **ap; 148 149 if (argc > 1) { 150 p = argv[1]; 151 if (argc > 2) { 152 STARTSTACKSTR(concat); 153 ap = argv + 2; 154 for (;;) { 155 while (*p) 156 STPUTC(*p++, concat); 157 if ((p = *ap++) == NULL) 158 break; 159 STPUTC(' ', concat); 160 } 161 STPUTC('\0', concat); 162 p = grabstackstr(concat); 163 } 164 evalstring(p); 165 } 166 return exitstatus; 167 } 168 169 170 /* 171 * Execute a command or commands contained in a string. 172 */ 173 174 void 175 evalstring(s) 176 char *s; 177 { 178 union node *n; 179 struct stackmark smark; 180 181 setstackmark(&smark); 182 setinputstring(s, 1); 183 while ((n = parsecmd(0)) != NEOF) { 184 evaltree(n, 0); 185 popstackmark(&smark); 186 } 187 popfile(); 188 popstackmark(&smark); 189 } 190 191 192 193 /* 194 * Evaluate a parse tree. The value is left in the global variable 195 * exitstatus. 196 */ 197 198 void 199 evaltree(n, flags) 200 union node *n; 201 int flags; 202 { 203 if (n == NULL) { 204 TRACE(("evaltree(NULL) called\n")); 205 exitstatus = 0; 206 goto out; 207 } 208 #ifndef NO_HISTORY 209 displayhist = 1; /* show history substitutions done with fc */ 210 #endif 211 TRACE(("evaltree(0x%x: %d) called\n", (int)n, n->type)); 212 switch (n->type) { 213 case NSEMI: 214 evaltree(n->nbinary.ch1, 0); 215 if (evalskip) 216 goto out; 217 evaltree(n->nbinary.ch2, flags); 218 break; 219 case NAND: 220 evaltree(n->nbinary.ch1, EV_TESTED); 221 if (evalskip || exitstatus != 0) 222 goto out; 223 evaltree(n->nbinary.ch2, flags); 224 break; 225 case NOR: 226 evaltree(n->nbinary.ch1, EV_TESTED); 227 if (evalskip || exitstatus == 0) 228 goto out; 229 evaltree(n->nbinary.ch2, flags); 230 break; 231 case NREDIR: 232 expredir(n->nredir.redirect); 233 redirect(n->nredir.redirect, REDIR_PUSH); 234 evaltree(n->nredir.n, flags); 235 popredir(); 236 break; 237 case NSUBSHELL: 238 evalsubshell(n, flags); 239 break; 240 case NBACKGND: 241 evalsubshell(n, flags); 242 break; 243 case NIF: { 244 int status = 0; 245 246 evaltree(n->nif.test, EV_TESTED); 247 if (evalskip) 248 goto out; 249 if (exitstatus == 0) { 250 evaltree(n->nif.ifpart, flags); 251 status = exitstatus; 252 } else if (n->nif.elsepart) { 253 evaltree(n->nif.elsepart, flags); 254 status = exitstatus; 255 } 256 exitstatus = status; 257 break; 258 } 259 case NWHILE: 260 case NUNTIL: 261 evalloop(n); 262 break; 263 case NFOR: 264 evalfor(n); 265 break; 266 case NCASE: 267 evalcase(n, flags); 268 break; 269 case NDEFUN: 270 defun(n->narg.text, n->narg.next); 271 exitstatus = 0; 272 break; 273 case NNOT: 274 evaltree(n->nnot.com, EV_TESTED); 275 exitstatus = !exitstatus; 276 break; 277 278 case NPIPE: 279 evalpipe(n); 280 break; 281 case NCMD: 282 evalcommand(n, flags, (struct backcmd *)NULL); 283 break; 284 default: 285 out1fmt("Node type = %d\n", n->type); 286 flushout(&output); 287 break; 288 } 289 out: 290 if (pendingsigs) 291 dotrap(); 292 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 293 exitshell(exitstatus); 294 } 295 296 297 STATIC void 298 evalloop(n) 299 union node *n; 300 { 301 int status; 302 303 loopnest++; 304 status = 0; 305 for (;;) { 306 evaltree(n->nbinary.ch1, EV_TESTED); 307 if (evalskip) { 308 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 309 evalskip = 0; 310 continue; 311 } 312 if (evalskip == SKIPBREAK && --skipcount <= 0) 313 evalskip = 0; 314 break; 315 } 316 if (n->type == NWHILE) { 317 if (exitstatus != 0) 318 break; 319 } else { 320 if (exitstatus == 0) 321 break; 322 } 323 evaltree(n->nbinary.ch2, 0); 324 status = exitstatus; 325 if (evalskip) 326 goto skipping; 327 } 328 loopnest--; 329 exitstatus = status; 330 } 331 332 333 334 STATIC void 335 evalfor(n) 336 union node *n; 337 { 338 struct arglist arglist; 339 union node *argp; 340 struct strlist *sp; 341 struct stackmark smark; 342 343 setstackmark(&smark); 344 arglist.lastp = &arglist.list; 345 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 346 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 347 if (evalskip) 348 goto out; 349 } 350 *arglist.lastp = NULL; 351 352 exitstatus = 0; 353 loopnest++; 354 for (sp = arglist.list ; sp ; sp = sp->next) { 355 setvar(n->nfor.var, sp->text, 0); 356 evaltree(n->nfor.body, 0); 357 if (evalskip) { 358 if (evalskip == SKIPCONT && --skipcount <= 0) { 359 evalskip = 0; 360 continue; 361 } 362 if (evalskip == SKIPBREAK && --skipcount <= 0) 363 evalskip = 0; 364 break; 365 } 366 } 367 loopnest--; 368 out: 369 popstackmark(&smark); 370 } 371 372 373 374 STATIC void 375 evalcase(n, flags) 376 union node *n; 377 int flags; 378 { 379 union node *cp; 380 union node *patp; 381 struct arglist arglist; 382 struct stackmark smark; 383 384 setstackmark(&smark); 385 arglist.lastp = &arglist.list; 386 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 387 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 388 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 389 if (casematch(patp, arglist.list->text)) { 390 if (evalskip == 0) { 391 evaltree(cp->nclist.body, flags); 392 } 393 goto out; 394 } 395 } 396 } 397 out: 398 popstackmark(&smark); 399 } 400 401 402 403 /* 404 * Kick off a subshell to evaluate a tree. 405 */ 406 407 STATIC void 408 evalsubshell(n, flags) 409 union node *n; 410 int flags; 411 { 412 struct job *jp; 413 int backgnd = (n->type == NBACKGND); 414 415 expredir(n->nredir.redirect); 416 jp = makejob(n, 1); 417 if (forkshell(jp, n, backgnd) == 0) { 418 if (backgnd) 419 flags &=~ EV_TESTED; 420 redirect(n->nredir.redirect, 0); 421 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 422 } 423 if (! backgnd) { 424 INTOFF; 425 exitstatus = waitforjob(jp); 426 INTON; 427 } 428 } 429 430 431 432 /* 433 * Compute the names of the files in a redirection list. 434 */ 435 436 STATIC void 437 expredir(n) 438 union node *n; 439 { 440 register union node *redir; 441 442 for (redir = n ; redir ; redir = redir->nfile.next) { 443 struct arglist fn; 444 fn.lastp = &fn.list; 445 switch (redir->type) { 446 case NFROM: 447 case NTO: 448 case NAPPEND: 449 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 450 redir->nfile.expfname = fn.list->text; 451 break; 452 case NFROMFD: 453 case NTOFD: 454 if (redir->ndup.vname) { 455 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 456 fixredir(redir, fn.list->text, 1); 457 } 458 break; 459 } 460 } 461 } 462 463 464 465 /* 466 * Evaluate a pipeline. All the processes in the pipeline are children 467 * of the process creating the pipeline. (This differs from some versions 468 * of the shell, which make the last process in a pipeline the parent 469 * of all the rest.) 470 */ 471 472 STATIC void 473 evalpipe(n) 474 union node *n; 475 { 476 struct job *jp; 477 struct nodelist *lp; 478 int pipelen; 479 int prevfd; 480 int pip[2]; 481 482 TRACE(("evalpipe(0x%x) called\n", (int)n)); 483 pipelen = 0; 484 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 485 pipelen++; 486 INTOFF; 487 jp = makejob(n, pipelen); 488 prevfd = -1; 489 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 490 prehash(lp->n); 491 pip[1] = -1; 492 if (lp->next) { 493 if (pipe(pip) < 0) { 494 close(prevfd); 495 error("Pipe call failed"); 496 } 497 } 498 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 499 INTON; 500 if (prevfd > 0) { 501 close(0); 502 copyfd(prevfd, 0); 503 close(prevfd); 504 } 505 if (pip[1] >= 0) { 506 close(pip[0]); 507 if (pip[1] != 1) { 508 close(1); 509 copyfd(pip[1], 1); 510 close(pip[1]); 511 } 512 } 513 evaltree(lp->n, EV_EXIT); 514 } 515 if (prevfd >= 0) 516 close(prevfd); 517 prevfd = pip[0]; 518 close(pip[1]); 519 } 520 INTON; 521 if (n->npipe.backgnd == 0) { 522 INTOFF; 523 exitstatus = waitforjob(jp); 524 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 525 INTON; 526 } 527 } 528 529 530 531 /* 532 * Execute a command inside back quotes. If it's a builtin command, we 533 * want to save its output in a block obtained from malloc. Otherwise 534 * we fork off a subprocess and get the output of the command via a pipe. 535 * Should be called with interrupts off. 536 */ 537 538 void 539 evalbackcmd(n, result) 540 union node *n; 541 struct backcmd *result; 542 { 543 int pip[2]; 544 struct job *jp; 545 struct stackmark smark; /* unnecessary */ 546 547 setstackmark(&smark); 548 result->fd = -1; 549 result->buf = NULL; 550 result->nleft = 0; 551 result->jp = NULL; 552 exitstatus = 0; 553 if (n == NULL) 554 goto out; 555 if (n->type == NCMD) { 556 evalcommand(n, EV_BACKCMD, result); 557 } else { 558 if (pipe(pip) < 0) 559 error("Pipe call failed"); 560 jp = makejob(n, 1); 561 if (forkshell(jp, n, FORK_NOJOB) == 0) { 562 FORCEINTON; 563 close(pip[0]); 564 if (pip[1] != 1) { 565 close(1); 566 copyfd(pip[1], 1); 567 close(pip[1]); 568 } 569 evaltree(n, EV_EXIT); 570 } 571 close(pip[1]); 572 result->fd = pip[0]; 573 result->jp = jp; 574 } 575 out: 576 popstackmark(&smark); 577 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 578 result->fd, result->buf, result->nleft, result->jp)); 579 } 580 581 582 583 /* 584 * Execute a simple command. 585 */ 586 587 STATIC void 588 evalcommand(cmd, flags, backcmd) 589 union node *cmd; 590 int flags; 591 struct backcmd *backcmd; 592 { 593 struct stackmark smark; 594 union node *argp; 595 struct arglist arglist; 596 struct arglist varlist; 597 char **argv; 598 int argc; 599 char **envp; 600 int varflag; 601 struct strlist *sp; 602 register char *p; 603 int mode; 604 int pip[2]; 605 struct cmdentry cmdentry; 606 struct job *jp; 607 struct jmploc jmploc; 608 struct jmploc *volatile savehandler; 609 char *volatile savecmdname; 610 volatile struct shparam saveparam; 611 struct localvar *volatile savelocalvars; 612 volatile int e; 613 char *lastarg; 614 615 /* First expand the arguments. */ 616 TRACE(("evalcommand(0x%x, %d) called\n", (int)cmd, flags)); 617 setstackmark(&smark); 618 arglist.lastp = &arglist.list; 619 varlist.lastp = &varlist.list; 620 varflag = 1; 621 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 622 p = argp->narg.text; 623 if (varflag && is_name(*p)) { 624 do { 625 p++; 626 } while (is_in_name(*p)); 627 if (*p == '=') { 628 expandarg(argp, &varlist, EXP_VARTILDE); 629 continue; 630 } 631 } 632 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 633 varflag = 0; 634 } 635 *arglist.lastp = NULL; 636 *varlist.lastp = NULL; 637 expredir(cmd->ncmd.redirect); 638 argc = 0; 639 for (sp = arglist.list ; sp ; sp = sp->next) 640 argc++; 641 argv = stalloc(sizeof (char *) * (argc + 1)); 642 643 for (sp = arglist.list ; sp ; sp = sp->next) { 644 TRACE(("evalcommand arg: %s\n", sp->text)); 645 *argv++ = sp->text; 646 } 647 *argv = NULL; 648 lastarg = NULL; 649 if (iflag && funcnest == 0 && argc > 0) 650 lastarg = argv[-1]; 651 argv -= argc; 652 653 /* Print the command if xflag is set. */ 654 if (xflag) { 655 outc('+', &errout); 656 for (sp = varlist.list ; sp ; sp = sp->next) { 657 outc(' ', &errout); 658 out2str(sp->text); 659 } 660 for (sp = arglist.list ; sp ; sp = sp->next) { 661 outc(' ', &errout); 662 out2str(sp->text); 663 } 664 outc('\n', &errout); 665 flushout(&errout); 666 } 667 668 /* Now locate the command. */ 669 if (argc == 0) { 670 cmdentry.cmdtype = CMDBUILTIN; 671 cmdentry.u.index = BLTINCMD; 672 } else { 673 find_command(argv[0], &cmdentry, 1); 674 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 675 exitstatus = 2; 676 flushout(&errout); 677 return; 678 } 679 /* implement the bltin builtin here */ 680 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 681 for (;;) { 682 argv++; 683 if (--argc == 0) 684 break; 685 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 686 outfmt(&errout, "%s: not found\n", *argv); 687 exitstatus = 2; 688 flushout(&errout); 689 return; 690 } 691 if (cmdentry.u.index != BLTINCMD) 692 break; 693 } 694 } 695 } 696 697 /* Fork off a child process if necessary. */ 698 if (cmd->ncmd.backgnd 699 || cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0 700 || (flags & EV_BACKCMD) != 0 701 && (cmdentry.cmdtype != CMDBUILTIN 702 || cmdentry.u.index == DOTCMD 703 || cmdentry.u.index == EVALCMD)) { 704 jp = makejob(cmd, 1); 705 mode = cmd->ncmd.backgnd; 706 if (flags & EV_BACKCMD) { 707 mode = FORK_NOJOB; 708 if (pipe(pip) < 0) 709 error("Pipe call failed"); 710 } 711 if (forkshell(jp, cmd, mode) != 0) 712 goto parent; /* at end of routine */ 713 if (flags & EV_BACKCMD) { 714 FORCEINTON; 715 close(pip[0]); 716 if (pip[1] != 1) { 717 close(1); 718 copyfd(pip[1], 1); 719 close(pip[1]); 720 } 721 } 722 flags |= EV_EXIT; 723 } 724 725 /* This is the child process if a fork occurred. */ 726 /* Execute the command. */ 727 if (cmdentry.cmdtype == CMDFUNCTION) { 728 trputs("Shell function: "); trargs(argv); 729 redirect(cmd->ncmd.redirect, REDIR_PUSH); 730 saveparam = shellparam; 731 shellparam.malloc = 0; 732 shellparam.nparam = argc - 1; 733 shellparam.p = argv + 1; 734 shellparam.optnext = NULL; 735 INTOFF; 736 savelocalvars = localvars; 737 localvars = NULL; 738 INTON; 739 if (setjmp(jmploc.loc)) { 740 if (exception == EXSHELLPROC) 741 freeparam((struct shparam *)&saveparam); 742 else { 743 freeparam(&shellparam); 744 shellparam = saveparam; 745 } 746 poplocalvars(); 747 localvars = savelocalvars; 748 handler = savehandler; 749 longjmp(handler->loc, 1); 750 } 751 savehandler = handler; 752 handler = &jmploc; 753 for (sp = varlist.list ; sp ; sp = sp->next) 754 mklocal(sp->text); 755 funcnest++; 756 evaltree(cmdentry.u.func, 0); 757 funcnest--; 758 INTOFF; 759 poplocalvars(); 760 localvars = savelocalvars; 761 freeparam(&shellparam); 762 shellparam = saveparam; 763 handler = savehandler; 764 popredir(); 765 INTON; 766 if (evalskip == SKIPFUNC) { 767 evalskip = 0; 768 skipcount = 0; 769 } 770 if (flags & EV_EXIT) 771 exitshell(exitstatus); 772 } else if (cmdentry.cmdtype == CMDBUILTIN) { 773 trputs("builtin command: "); trargs(argv); 774 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 775 if (flags == EV_BACKCMD) { 776 memout.nleft = 0; 777 memout.nextc = memout.buf; 778 memout.bufsize = 64; 779 mode |= REDIR_BACKQ; 780 } 781 redirect(cmd->ncmd.redirect, mode); 782 savecmdname = commandname; 783 cmdenviron = varlist.list; 784 e = -1; 785 if (setjmp(jmploc.loc)) { 786 e = exception; 787 exitstatus = (e == EXINT)? SIGINT+128 : 2; 788 goto cmddone; 789 } 790 savehandler = handler; 791 handler = &jmploc; 792 commandname = argv[0]; 793 argptr = argv + 1; 794 optptr = NULL; /* initialize nextopt */ 795 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 796 flushall(); 797 cmddone: 798 out1 = &output; 799 out2 = &errout; 800 freestdout(); 801 if (e != EXSHELLPROC) { 802 commandname = savecmdname; 803 if (flags & EV_EXIT) { 804 exitshell(exitstatus); 805 } 806 } 807 handler = savehandler; 808 if (e != -1) { 809 if (e != EXERROR || cmdentry.u.index == BLTINCMD 810 || cmdentry.u.index == DOTCMD 811 || cmdentry.u.index == EVALCMD 812 #ifndef NO_HISTORY 813 || cmdentry.u.index == HISTCMD 814 #endif 815 || cmdentry.u.index == EXECCMD) 816 exraise(e); 817 FORCEINTON; 818 } 819 if (cmdentry.u.index != EXECCMD) 820 popredir(); 821 if (flags == EV_BACKCMD) { 822 backcmd->buf = memout.buf; 823 backcmd->nleft = memout.nextc - memout.buf; 824 memout.buf = NULL; 825 } 826 } else { 827 trputs("normal command: "); trargs(argv); 828 clearredir(); 829 redirect(cmd->ncmd.redirect, 0); 830 if (varlist.list) { 831 p = stalloc(strlen(pathval()) + 1); 832 scopy(pathval(), p); 833 } else { 834 p = pathval(); 835 } 836 for (sp = varlist.list ; sp ; sp = sp->next) 837 setvareq(sp->text, VEXPORT|VSTACK); 838 envp = environment(); 839 shellexec(argv, envp, p, cmdentry.u.index); 840 /*NOTREACHED*/ 841 } 842 goto out; 843 844 parent: /* parent process gets here (if we forked) */ 845 if (mode == 0) { /* argument to fork */ 846 INTOFF; 847 exitstatus = waitforjob(jp); 848 INTON; 849 } else if (mode == 2) { 850 backcmd->fd = pip[0]; 851 close(pip[1]); 852 backcmd->jp = jp; 853 } 854 855 out: 856 if (lastarg) 857 setvar("_", lastarg, 0); 858 popstackmark(&smark); 859 } 860 861 862 863 /* 864 * Search for a command. This is called before we fork so that the 865 * location of the command will be available in the parent as well as 866 * the child. The check for "goodname" is an overly conservative 867 * check that the name will not be subject to expansion. 868 */ 869 870 STATIC void 871 prehash(n) 872 union node *n; 873 { 874 struct cmdentry entry; 875 876 if (n->type == NCMD && n->ncmd.args) 877 if (goodname(n->ncmd.args->narg.text)) 878 find_command(n->ncmd.args->narg.text, &entry, 0); 879 } 880 881 882 883 /* 884 * Builtin commands. Builtin commands whose functions are closely 885 * tied to evaluation are implemented here. 886 */ 887 888 /* 889 * No command given, or a bltin command with no arguments. Set the 890 * specified variables. 891 */ 892 893 int 894 bltincmd(argc, argv) 895 int argc; 896 char **argv; 897 { 898 listsetvar(cmdenviron); 899 return 0; 900 } 901 902 903 /* 904 * Handle break and continue commands. Break, continue, and return are 905 * all handled by setting the evalskip flag. The evaluation routines 906 * above all check this flag, and if it is set they start skipping 907 * commands rather than executing them. The variable skipcount is 908 * the number of loops to break/continue, or the number of function 909 * levels to return. (The latter is always 1.) It should probably 910 * be an error to break out of more loops than exist, but it isn't 911 * in the standard shell so we don't make it one here. 912 */ 913 914 int 915 breakcmd(argc, argv) 916 int argc; 917 char **argv; 918 { 919 int n; 920 921 n = 1; 922 if (argc > 1) 923 n = number(argv[1]); 924 if (n > loopnest) 925 n = loopnest; 926 if (n > 0) { 927 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 928 skipcount = n; 929 } 930 return 0; 931 } 932 933 934 /* 935 * The return command. 936 */ 937 938 int 939 returncmd(argc, argv) 940 int argc; 941 char **argv; 942 { 943 int ret; 944 945 ret = exitstatus; 946 if (argc > 1) 947 ret = number(argv[1]); 948 if (funcnest) { 949 evalskip = SKIPFUNC; 950 skipcount = 1; 951 } 952 return ret; 953 } 954 955 956 int 957 falsecmd(argc, argv) 958 int argc; 959 char **argv; 960 { 961 return 1; 962 } 963 964 965 int 966 truecmd(argc, argv) 967 int argc; 968 char **argv; 969 { 970 return 0; 971 } 972 973 974 int 975 execcmd(argc, argv) 976 int argc; 977 char **argv; 978 { 979 if (argc > 1) { 980 iflag = 0; /* exit on error */ 981 mflag = 0; 982 optschanged(); 983 shellexec(argv + 1, environment(), pathval(), 0); 984 985 } 986 return 0; 987 } 988