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 * $Id: eval.c,v 1.8 1996/11/12 18:35:06 peter Exp $ 37 */ 38 39 #ifndef lint 40 static char const sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 41 #endif /* not lint */ 42 43 #include <signal.h> 44 #include <unistd.h> 45 46 /* 47 * Evaluate a command. 48 */ 49 50 #include "shell.h" 51 #include "nodes.h" 52 #include "syntax.h" 53 #include "expand.h" 54 #include "parser.h" 55 #include "jobs.h" 56 #include "eval.h" 57 #include "builtins.h" 58 #include "options.h" 59 #include "exec.h" 60 #include "redir.h" 61 #include "input.h" 62 #include "output.h" 63 #include "trap.h" 64 #include "var.h" 65 #include "memalloc.h" 66 #include "error.h" 67 #include "show.h" 68 #include "mystring.h" 69 #ifndef NO_HISTORY 70 #include "myhistedit.h" 71 #endif 72 73 74 /* flags in argument to evaltree */ 75 #define EV_EXIT 01 /* exit after evaluating tree */ 76 #define EV_TESTED 02 /* exit status is checked; ignore -e flag */ 77 #define EV_BACKCMD 04 /* command executing within back quotes */ 78 79 MKINIT int evalskip; /* set if we are skipping commands */ 80 STATIC int skipcount; /* number of levels to skip */ 81 MKINIT int loopnest; /* current loop nesting level */ 82 int funcnest; /* depth of function calls */ 83 84 85 char *commandname; 86 struct strlist *cmdenviron; 87 int exitstatus; /* exit status of last command */ 88 int oexitstatus; /* saved exit status */ 89 90 91 STATIC void evalloop __P((union node *)); 92 STATIC void evalfor __P((union node *)); 93 STATIC void evalcase __P((union node *, int)); 94 STATIC void evalsubshell __P((union node *, int)); 95 STATIC void expredir __P((union node *)); 96 STATIC void evalpipe __P((union node *)); 97 STATIC void evalcommand __P((union node *, int, struct backcmd *)); 98 STATIC void prehash __P((union node *)); 99 100 101 /* 102 * Called to reset things after an exception. 103 */ 104 105 #ifdef mkinit 106 INCLUDE "eval.h" 107 108 RESET { 109 evalskip = 0; 110 loopnest = 0; 111 funcnest = 0; 112 } 113 114 SHELLPROC { 115 exitstatus = 0; 116 } 117 #endif 118 119 120 121 /* 122 * The eval commmand. 123 */ 124 125 int 126 evalcmd(argc, argv) 127 int argc; 128 char **argv; 129 { 130 char *p; 131 char *concat; 132 char **ap; 133 134 if (argc > 1) { 135 p = argv[1]; 136 if (argc > 2) { 137 STARTSTACKSTR(concat); 138 ap = argv + 2; 139 for (;;) { 140 while (*p) 141 STPUTC(*p++, concat); 142 if ((p = *ap++) == NULL) 143 break; 144 STPUTC(' ', concat); 145 } 146 STPUTC('\0', concat); 147 p = grabstackstr(concat); 148 } 149 evalstring(p); 150 } 151 return exitstatus; 152 } 153 154 155 /* 156 * Execute a command or commands contained in a string. 157 */ 158 159 void 160 evalstring(s) 161 char *s; 162 { 163 union node *n; 164 struct stackmark smark; 165 166 setstackmark(&smark); 167 setinputstring(s, 1); 168 while ((n = parsecmd(0)) != NEOF) { 169 evaltree(n, 0); 170 popstackmark(&smark); 171 } 172 popfile(); 173 popstackmark(&smark); 174 } 175 176 177 178 /* 179 * Evaluate a parse tree. The value is left in the global variable 180 * exitstatus. 181 */ 182 183 void 184 evaltree(n, flags) 185 union node *n; 186 int flags; 187 { 188 if (n == NULL) { 189 TRACE(("evaltree(NULL) called\n")); 190 exitstatus = 0; 191 goto out; 192 } 193 #ifndef NO_HISTORY 194 displayhist = 1; /* show history substitutions done with fc */ 195 #endif 196 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type)); 197 switch (n->type) { 198 case NSEMI: 199 evaltree(n->nbinary.ch1, 0); 200 if (evalskip) 201 goto out; 202 evaltree(n->nbinary.ch2, flags); 203 break; 204 case NAND: 205 evaltree(n->nbinary.ch1, EV_TESTED); 206 if (evalskip || exitstatus != 0) { 207 flags |= EV_TESTED; 208 goto out; 209 } 210 evaltree(n->nbinary.ch2, flags); 211 break; 212 case NOR: 213 evaltree(n->nbinary.ch1, EV_TESTED); 214 if (evalskip || exitstatus == 0) 215 goto out; 216 evaltree(n->nbinary.ch2, flags); 217 break; 218 case NREDIR: 219 expredir(n->nredir.redirect); 220 redirect(n->nredir.redirect, REDIR_PUSH); 221 evaltree(n->nredir.n, flags); 222 popredir(); 223 break; 224 case NSUBSHELL: 225 evalsubshell(n, flags); 226 break; 227 case NBACKGND: 228 evalsubshell(n, flags); 229 break; 230 case NIF: { 231 evaltree(n->nif.test, EV_TESTED); 232 if (evalskip) 233 goto out; 234 if (exitstatus == 0) 235 evaltree(n->nif.ifpart, flags); 236 else if (n->nif.elsepart) 237 evaltree(n->nif.elsepart, flags); 238 else 239 exitstatus = 0; 240 break; 241 } 242 case NWHILE: 243 case NUNTIL: 244 evalloop(n); 245 break; 246 case NFOR: 247 evalfor(n); 248 break; 249 case NCASE: 250 evalcase(n, flags); 251 break; 252 case NDEFUN: 253 defun(n->narg.text, n->narg.next); 254 exitstatus = 0; 255 break; 256 case NNOT: 257 evaltree(n->nnot.com, EV_TESTED); 258 exitstatus = !exitstatus; 259 break; 260 261 case NPIPE: 262 evalpipe(n); 263 break; 264 case NCMD: 265 evalcommand(n, flags, (struct backcmd *)NULL); 266 break; 267 default: 268 out1fmt("Node type = %d\n", n->type); 269 flushout(&output); 270 break; 271 } 272 out: 273 if (pendingsigs) 274 dotrap(); 275 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 276 exitshell(exitstatus); 277 } 278 279 280 STATIC void 281 evalloop(n) 282 union node *n; 283 { 284 int status; 285 286 loopnest++; 287 status = 0; 288 for (;;) { 289 evaltree(n->nbinary.ch1, EV_TESTED); 290 if (evalskip) { 291 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 292 evalskip = 0; 293 continue; 294 } 295 if (evalskip == SKIPBREAK && --skipcount <= 0) 296 evalskip = 0; 297 break; 298 } 299 if (n->type == NWHILE) { 300 if (exitstatus != 0) 301 break; 302 } else { 303 if (exitstatus == 0) 304 break; 305 } 306 evaltree(n->nbinary.ch2, 0); 307 status = exitstatus; 308 if (evalskip) 309 goto skipping; 310 } 311 loopnest--; 312 exitstatus = status; 313 } 314 315 316 317 STATIC void 318 evalfor(n) 319 union node *n; 320 { 321 struct arglist arglist; 322 union node *argp; 323 struct strlist *sp; 324 struct stackmark smark; 325 326 setstackmark(&smark); 327 arglist.lastp = &arglist.list; 328 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 329 oexitstatus = exitstatus; 330 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 331 if (evalskip) 332 goto out; 333 } 334 *arglist.lastp = NULL; 335 336 exitstatus = 0; 337 loopnest++; 338 for (sp = arglist.list ; sp ; sp = sp->next) { 339 setvar(n->nfor.var, sp->text, 0); 340 evaltree(n->nfor.body, 0); 341 if (evalskip) { 342 if (evalskip == SKIPCONT && --skipcount <= 0) { 343 evalskip = 0; 344 continue; 345 } 346 if (evalskip == SKIPBREAK && --skipcount <= 0) 347 evalskip = 0; 348 break; 349 } 350 } 351 loopnest--; 352 out: 353 popstackmark(&smark); 354 } 355 356 357 358 STATIC void 359 evalcase(n, flags) 360 union node *n; 361 int flags; 362 { 363 union node *cp; 364 union node *patp; 365 struct arglist arglist; 366 struct stackmark smark; 367 368 setstackmark(&smark); 369 arglist.lastp = &arglist.list; 370 oexitstatus = exitstatus; 371 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 372 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 373 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 374 if (casematch(patp, arglist.list->text)) { 375 if (evalskip == 0) { 376 evaltree(cp->nclist.body, flags); 377 } 378 goto out; 379 } 380 } 381 } 382 out: 383 popstackmark(&smark); 384 } 385 386 387 388 /* 389 * Kick off a subshell to evaluate a tree. 390 */ 391 392 STATIC void 393 evalsubshell(n, flags) 394 union node *n; 395 int flags; 396 { 397 struct job *jp; 398 int backgnd = (n->type == NBACKGND); 399 400 expredir(n->nredir.redirect); 401 jp = makejob(n, 1); 402 if (forkshell(jp, n, backgnd) == 0) { 403 if (backgnd) 404 flags &=~ EV_TESTED; 405 redirect(n->nredir.redirect, 0); 406 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 407 } 408 if (! backgnd) { 409 INTOFF; 410 exitstatus = waitforjob(jp); 411 INTON; 412 } 413 } 414 415 416 417 /* 418 * Compute the names of the files in a redirection list. 419 */ 420 421 STATIC void 422 expredir(n) 423 union node *n; 424 { 425 register union node *redir; 426 427 for (redir = n ; redir ; redir = redir->nfile.next) { 428 struct arglist fn; 429 fn.lastp = &fn.list; 430 oexitstatus = exitstatus; 431 switch (redir->type) { 432 case NFROM: 433 case NTO: 434 case NAPPEND: 435 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 436 redir->nfile.expfname = fn.list->text; 437 break; 438 case NFROMFD: 439 case NTOFD: 440 if (redir->ndup.vname) { 441 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 442 fixredir(redir, fn.list->text, 1); 443 } 444 break; 445 } 446 } 447 } 448 449 450 451 /* 452 * Evaluate a pipeline. All the processes in the pipeline are children 453 * of the process creating the pipeline. (This differs from some versions 454 * of the shell, which make the last process in a pipeline the parent 455 * of all the rest.) 456 */ 457 458 STATIC void 459 evalpipe(n) 460 union node *n; 461 { 462 struct job *jp; 463 struct nodelist *lp; 464 int pipelen; 465 int prevfd; 466 int pip[2]; 467 468 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 469 pipelen = 0; 470 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 471 pipelen++; 472 INTOFF; 473 jp = makejob(n, pipelen); 474 prevfd = -1; 475 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 476 prehash(lp->n); 477 pip[1] = -1; 478 if (lp->next) { 479 if (pipe(pip) < 0) { 480 close(prevfd); 481 error("Pipe call failed"); 482 } 483 } 484 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 485 INTON; 486 if (prevfd > 0) { 487 close(0); 488 copyfd(prevfd, 0); 489 close(prevfd); 490 } 491 if (pip[1] >= 0) { 492 close(pip[0]); 493 if (pip[1] != 1) { 494 close(1); 495 copyfd(pip[1], 1); 496 close(pip[1]); 497 } 498 } 499 evaltree(lp->n, EV_EXIT); 500 } 501 if (prevfd >= 0) 502 close(prevfd); 503 prevfd = pip[0]; 504 close(pip[1]); 505 } 506 INTON; 507 if (n->npipe.backgnd == 0) { 508 INTOFF; 509 exitstatus = waitforjob(jp); 510 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 511 INTON; 512 } 513 } 514 515 516 517 /* 518 * Execute a command inside back quotes. If it's a builtin command, we 519 * want to save its output in a block obtained from malloc. Otherwise 520 * we fork off a subprocess and get the output of the command via a pipe. 521 * Should be called with interrupts off. 522 */ 523 524 void 525 evalbackcmd(n, result) 526 union node *n; 527 struct backcmd *result; 528 { 529 int pip[2]; 530 struct job *jp; 531 struct stackmark smark; /* unnecessary */ 532 533 setstackmark(&smark); 534 result->fd = -1; 535 result->buf = NULL; 536 result->nleft = 0; 537 result->jp = NULL; 538 if (n == NULL) { 539 exitstatus = 0; 540 goto out; 541 } 542 if (n->type == NCMD) { 543 exitstatus = oexitstatus; 544 evalcommand(n, EV_BACKCMD, result); 545 } else { 546 exitstatus = 0; 547 if (pipe(pip) < 0) 548 error("Pipe call failed"); 549 jp = makejob(n, 1); 550 if (forkshell(jp, n, FORK_NOJOB) == 0) { 551 FORCEINTON; 552 close(pip[0]); 553 if (pip[1] != 1) { 554 close(1); 555 copyfd(pip[1], 1); 556 close(pip[1]); 557 } 558 evaltree(n, EV_EXIT); 559 } 560 close(pip[1]); 561 result->fd = pip[0]; 562 result->jp = jp; 563 } 564 out: 565 popstackmark(&smark); 566 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 567 result->fd, result->buf, result->nleft, result->jp)); 568 } 569 570 571 572 /* 573 * Execute a simple command. 574 */ 575 576 STATIC void 577 evalcommand(cmd, flags, backcmd) 578 union node *cmd; 579 int flags; 580 struct backcmd *backcmd; 581 { 582 struct stackmark smark; 583 union node *argp; 584 struct arglist arglist; 585 struct arglist varlist; 586 char **argv; 587 int argc; 588 char **envp; 589 int varflag; 590 struct strlist *sp; 591 int mode; 592 int pip[2]; 593 struct cmdentry cmdentry; 594 struct job *jp; 595 struct jmploc jmploc; 596 struct jmploc *volatile savehandler; 597 char *volatile savecmdname; 598 volatile struct shparam saveparam; 599 struct localvar *volatile savelocalvars; 600 volatile int e; 601 char *lastarg; 602 #if __GNUC__ 603 /* Avoid longjmp clobbering */ 604 (void) &argv; 605 (void) &argc; 606 (void) &lastarg; 607 (void) &flags; 608 #endif 609 610 /* First expand the arguments. */ 611 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 612 setstackmark(&smark); 613 arglist.lastp = &arglist.list; 614 varlist.lastp = &varlist.list; 615 varflag = 1; 616 oexitstatus = exitstatus; 617 exitstatus = 0; 618 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 619 char *p = argp->narg.text; 620 if (varflag && is_name(*p)) { 621 do { 622 p++; 623 } while (is_in_name(*p)); 624 if (*p == '=') { 625 expandarg(argp, &varlist, EXP_VARTILDE); 626 continue; 627 } 628 } 629 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 630 varflag = 0; 631 } 632 *arglist.lastp = NULL; 633 *varlist.lastp = NULL; 634 expredir(cmd->ncmd.redirect); 635 argc = 0; 636 for (sp = arglist.list ; sp ; sp = sp->next) 637 argc++; 638 argv = stalloc(sizeof (char *) * (argc + 1)); 639 640 for (sp = arglist.list ; sp ; sp = sp->next) { 641 TRACE(("evalcommand arg: %s\n", sp->text)); 642 *argv++ = sp->text; 643 } 644 *argv = NULL; 645 lastarg = NULL; 646 if (iflag && funcnest == 0 && argc > 0) 647 lastarg = argv[-1]; 648 argv -= argc; 649 650 /* Print the command if xflag is set. */ 651 if (xflag) { 652 outc('+', &errout); 653 for (sp = varlist.list ; sp ; sp = sp->next) { 654 outc(' ', &errout); 655 out2str(sp->text); 656 } 657 for (sp = arglist.list ; sp ; sp = sp->next) { 658 outc(' ', &errout); 659 out2str(sp->text); 660 } 661 outc('\n', &errout); 662 flushout(&errout); 663 } 664 665 /* Now locate the command. */ 666 if (argc == 0) { 667 cmdentry.cmdtype = CMDBUILTIN; 668 cmdentry.u.index = BLTINCMD; 669 } else { 670 static const char PATH[] = "PATH="; 671 char *path = pathval(); 672 673 /* 674 * Modify the command lookup path, if a PATH= assignment 675 * is present 676 */ 677 for (sp = varlist.list ; sp ; sp = sp->next) 678 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) 679 path = sp->text + sizeof(PATH) - 1; 680 681 find_command(argv[0], &cmdentry, 1, path); 682 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 683 exitstatus = 127; 684 flushout(&errout); 685 return; 686 } 687 /* implement the bltin builtin here */ 688 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 689 for (;;) { 690 argv++; 691 if (--argc == 0) 692 break; 693 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 694 outfmt(&errout, "%s: not found\n", *argv); 695 exitstatus = 127; 696 flushout(&errout); 697 return; 698 } 699 if (cmdentry.u.index != BLTINCMD) 700 break; 701 } 702 } 703 } 704 705 /* Fork off a child process if necessary. */ 706 if (cmd->ncmd.backgnd 707 || (cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0) 708 || ((flags & EV_BACKCMD) != 0 709 && (cmdentry.cmdtype != CMDBUILTIN 710 || cmdentry.u.index == DOTCMD 711 || cmdentry.u.index == EVALCMD))) { 712 jp = makejob(cmd, 1); 713 mode = cmd->ncmd.backgnd; 714 if (flags & EV_BACKCMD) { 715 mode = FORK_NOJOB; 716 if (pipe(pip) < 0) 717 error("Pipe call failed"); 718 } 719 if (forkshell(jp, cmd, mode) != 0) 720 goto parent; /* at end of routine */ 721 if (flags & EV_BACKCMD) { 722 FORCEINTON; 723 close(pip[0]); 724 if (pip[1] != 1) { 725 close(1); 726 copyfd(pip[1], 1); 727 close(pip[1]); 728 } 729 } 730 flags |= EV_EXIT; 731 } 732 733 /* This is the child process if a fork occurred. */ 734 /* Execute the command. */ 735 if (cmdentry.cmdtype == CMDFUNCTION) { 736 #ifdef DEBUG 737 trputs("Shell function: "); trargs(argv); 738 #endif 739 redirect(cmd->ncmd.redirect, REDIR_PUSH); 740 saveparam = shellparam; 741 shellparam.malloc = 0; 742 shellparam.reset = 1; 743 shellparam.nparam = argc - 1; 744 shellparam.p = argv + 1; 745 shellparam.optnext = NULL; 746 INTOFF; 747 savelocalvars = localvars; 748 localvars = NULL; 749 INTON; 750 if (setjmp(jmploc.loc)) { 751 if (exception == EXSHELLPROC) 752 freeparam((struct shparam *)&saveparam); 753 else { 754 freeparam(&shellparam); 755 shellparam = saveparam; 756 } 757 poplocalvars(); 758 localvars = savelocalvars; 759 handler = savehandler; 760 longjmp(handler->loc, 1); 761 } 762 savehandler = handler; 763 handler = &jmploc; 764 for (sp = varlist.list ; sp ; sp = sp->next) 765 mklocal(sp->text); 766 funcnest++; 767 evaltree(cmdentry.u.func, 0); 768 funcnest--; 769 INTOFF; 770 poplocalvars(); 771 localvars = savelocalvars; 772 freeparam(&shellparam); 773 shellparam = saveparam; 774 handler = savehandler; 775 popredir(); 776 INTON; 777 if (evalskip == SKIPFUNC) { 778 evalskip = 0; 779 skipcount = 0; 780 } 781 if (flags & EV_EXIT) 782 exitshell(exitstatus); 783 } else if (cmdentry.cmdtype == CMDBUILTIN) { 784 #ifdef DEBUG 785 trputs("builtin command: "); trargs(argv); 786 #endif 787 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 788 if (flags == EV_BACKCMD) { 789 memout.nleft = 0; 790 memout.nextc = memout.buf; 791 memout.bufsize = 64; 792 mode |= REDIR_BACKQ; 793 } 794 redirect(cmd->ncmd.redirect, mode); 795 savecmdname = commandname; 796 cmdenviron = varlist.list; 797 e = -1; 798 if (setjmp(jmploc.loc)) { 799 e = exception; 800 exitstatus = (e == EXINT)? SIGINT+128 : 2; 801 goto cmddone; 802 } 803 savehandler = handler; 804 handler = &jmploc; 805 commandname = argv[0]; 806 argptr = argv + 1; 807 optptr = NULL; /* initialize nextopt */ 808 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 809 flushall(); 810 cmddone: 811 out1 = &output; 812 out2 = &errout; 813 freestdout(); 814 if (e != EXSHELLPROC) { 815 commandname = savecmdname; 816 if (flags & EV_EXIT) { 817 exitshell(exitstatus); 818 } 819 } 820 handler = savehandler; 821 if (e != -1) { 822 if ((e != EXERROR && e != EXEXEC) 823 || cmdentry.u.index == BLTINCMD 824 || cmdentry.u.index == DOTCMD 825 || cmdentry.u.index == EVALCMD 826 #ifndef NO_HISTORY 827 || cmdentry.u.index == HISTCMD 828 #endif 829 || cmdentry.u.index == EXECCMD) 830 exraise(e); 831 FORCEINTON; 832 } 833 if (cmdentry.u.index != EXECCMD) 834 popredir(); 835 if (flags == EV_BACKCMD) { 836 backcmd->buf = memout.buf; 837 backcmd->nleft = memout.nextc - memout.buf; 838 memout.buf = NULL; 839 } 840 } else { 841 #ifdef DEBUG 842 trputs("normal command: "); trargs(argv); 843 #endif 844 clearredir(); 845 redirect(cmd->ncmd.redirect, 0); 846 for (sp = varlist.list ; sp ; sp = sp->next) 847 setvareq(sp->text, VEXPORT|VSTACK); 848 envp = environment(); 849 shellexec(argv, envp, pathval(), cmdentry.u.index); 850 /*NOTREACHED*/ 851 } 852 goto out; 853 854 parent: /* parent process gets here (if we forked) */ 855 if (mode == 0) { /* argument to fork */ 856 INTOFF; 857 exitstatus = waitforjob(jp); 858 INTON; 859 } else if (mode == 2) { 860 backcmd->fd = pip[0]; 861 close(pip[1]); 862 backcmd->jp = jp; 863 } 864 865 out: 866 if (lastarg) 867 setvar("_", lastarg, 0); 868 popstackmark(&smark); 869 } 870 871 872 873 /* 874 * Search for a command. This is called before we fork so that the 875 * location of the command will be available in the parent as well as 876 * the child. The check for "goodname" is an overly conservative 877 * check that the name will not be subject to expansion. 878 */ 879 880 STATIC void 881 prehash(n) 882 union node *n; 883 { 884 struct cmdentry entry; 885 886 if (n->type == NCMD && n->ncmd.args) 887 if (goodname(n->ncmd.args->narg.text)) 888 find_command(n->ncmd.args->narg.text, &entry, 0, 889 pathval()); 890 } 891 892 893 894 /* 895 * Builtin commands. Builtin commands whose functions are closely 896 * tied to evaluation are implemented here. 897 */ 898 899 /* 900 * No command given, or a bltin command with no arguments. Set the 901 * specified variables. 902 */ 903 904 int 905 bltincmd(argc, argv) 906 int argc; 907 char **argv; 908 { 909 listsetvar(cmdenviron); 910 /* 911 * Preserve exitstatus of a previous possible redirection 912 * as POSIX mandates 913 */ 914 return exitstatus; 915 } 916 917 918 /* 919 * Handle break and continue commands. Break, continue, and return are 920 * all handled by setting the evalskip flag. The evaluation routines 921 * above all check this flag, and if it is set they start skipping 922 * commands rather than executing them. The variable skipcount is 923 * the number of loops to break/continue, or the number of function 924 * levels to return. (The latter is always 1.) It should probably 925 * be an error to break out of more loops than exist, but it isn't 926 * in the standard shell so we don't make it one here. 927 */ 928 929 int 930 breakcmd(argc, argv) 931 int argc; 932 char **argv; 933 { 934 int n = argc > 1 ? number(argv[1]) : 1; 935 936 if (n > loopnest) 937 n = loopnest; 938 if (n > 0) { 939 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 940 skipcount = n; 941 } 942 return 0; 943 } 944 945 946 /* 947 * The return command. 948 */ 949 950 int 951 returncmd(argc, argv) 952 int argc; 953 char **argv; 954 { 955 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 956 957 if (funcnest) { 958 evalskip = SKIPFUNC; 959 skipcount = 1; 960 } else { 961 /* skip the rest of the file */ 962 evalskip = SKIPFILE; 963 skipcount = 1; 964 } 965 return ret; 966 } 967 968 969 int 970 falsecmd(argc, argv) 971 int argc; 972 char **argv; 973 { 974 return 1; 975 } 976 977 978 int 979 truecmd(argc, argv) 980 int argc; 981 char **argv; 982 { 983 return 0; 984 } 985 986 987 int 988 execcmd(argc, argv) 989 int argc; 990 char **argv; 991 { 992 if (argc > 1) { 993 struct strlist *sp; 994 995 iflag = 0; /* exit on error */ 996 mflag = 0; 997 optschanged(); 998 for (sp = cmdenviron; sp ; sp = sp->next) 999 setvareq(sp->text, VEXPORT|VSTACK); 1000 shellexec(argv + 1, environment(), pathval(), 0); 1001 1002 } 1003 return 0; 1004 } 1005