1 /* $NetBSD: eval.c,v 1.30 1996/06/03 12:21:17 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 1.30 1996/06/03 12:21:17 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 goto out; 212 evaltree(n->nbinary.ch2, flags); 213 break; 214 case NOR: 215 evaltree(n->nbinary.ch1, EV_TESTED); 216 if (evalskip || exitstatus == 0) 217 goto out; 218 evaltree(n->nbinary.ch2, flags); 219 break; 220 case NREDIR: 221 expredir(n->nredir.redirect); 222 redirect(n->nredir.redirect, REDIR_PUSH); 223 evaltree(n->nredir.n, flags); 224 popredir(); 225 break; 226 case NSUBSHELL: 227 evalsubshell(n, flags); 228 break; 229 case NBACKGND: 230 evalsubshell(n, flags); 231 break; 232 case NIF: { 233 evaltree(n->nif.test, EV_TESTED); 234 if (evalskip) 235 goto out; 236 if (exitstatus == 0) 237 evaltree(n->nif.ifpart, flags); 238 else if (n->nif.elsepart) 239 evaltree(n->nif.elsepart, flags); 240 else 241 exitstatus = 0; 242 break; 243 } 244 case NWHILE: 245 case NUNTIL: 246 evalloop(n); 247 break; 248 case NFOR: 249 evalfor(n); 250 break; 251 case NCASE: 252 evalcase(n, flags); 253 break; 254 case NDEFUN: 255 defun(n->narg.text, n->narg.next); 256 exitstatus = 0; 257 break; 258 case NNOT: 259 evaltree(n->nnot.com, EV_TESTED); 260 exitstatus = !exitstatus; 261 break; 262 263 case NPIPE: 264 evalpipe(n); 265 break; 266 case NCMD: 267 evalcommand(n, flags, (struct backcmd *)NULL); 268 break; 269 default: 270 out1fmt("Node type = %d\n", n->type); 271 flushout(&output); 272 break; 273 } 274 out: 275 if (pendingsigs) 276 dotrap(); 277 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 278 exitshell(exitstatus); 279 } 280 281 282 STATIC void 283 evalloop(n) 284 union node *n; 285 { 286 int status; 287 288 loopnest++; 289 status = 0; 290 for (;;) { 291 evaltree(n->nbinary.ch1, EV_TESTED); 292 if (evalskip) { 293 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 294 evalskip = 0; 295 continue; 296 } 297 if (evalskip == SKIPBREAK && --skipcount <= 0) 298 evalskip = 0; 299 break; 300 } 301 if (n->type == NWHILE) { 302 if (exitstatus != 0) 303 break; 304 } else { 305 if (exitstatus == 0) 306 break; 307 } 308 evaltree(n->nbinary.ch2, 0); 309 status = exitstatus; 310 if (evalskip) 311 goto skipping; 312 } 313 loopnest--; 314 exitstatus = status; 315 } 316 317 318 319 STATIC void 320 evalfor(n) 321 union node *n; 322 { 323 struct arglist arglist; 324 union node *argp; 325 struct strlist *sp; 326 struct stackmark smark; 327 328 setstackmark(&smark); 329 arglist.lastp = &arglist.list; 330 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 331 oexitstatus = exitstatus; 332 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 333 if (evalskip) 334 goto out; 335 } 336 *arglist.lastp = NULL; 337 338 exitstatus = 0; 339 loopnest++; 340 for (sp = arglist.list ; sp ; sp = sp->next) { 341 setvar(n->nfor.var, sp->text, 0); 342 evaltree(n->nfor.body, 0); 343 if (evalskip) { 344 if (evalskip == SKIPCONT && --skipcount <= 0) { 345 evalskip = 0; 346 continue; 347 } 348 if (evalskip == SKIPBREAK && --skipcount <= 0) 349 evalskip = 0; 350 break; 351 } 352 } 353 loopnest--; 354 out: 355 popstackmark(&smark); 356 } 357 358 359 360 STATIC void 361 evalcase(n, flags) 362 union node *n; 363 int flags; 364 { 365 union node *cp; 366 union node *patp; 367 struct arglist arglist; 368 struct stackmark smark; 369 370 setstackmark(&smark); 371 arglist.lastp = &arglist.list; 372 oexitstatus = exitstatus; 373 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 374 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 375 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 376 if (casematch(patp, arglist.list->text)) { 377 if (evalskip == 0) { 378 evaltree(cp->nclist.body, flags); 379 } 380 goto out; 381 } 382 } 383 } 384 out: 385 popstackmark(&smark); 386 } 387 388 389 390 /* 391 * Kick off a subshell to evaluate a tree. 392 */ 393 394 STATIC void 395 evalsubshell(n, flags) 396 union node *n; 397 int flags; 398 { 399 struct job *jp; 400 int backgnd = (n->type == NBACKGND); 401 402 expredir(n->nredir.redirect); 403 jp = makejob(n, 1); 404 if (forkshell(jp, n, backgnd) == 0) { 405 if (backgnd) 406 flags &=~ EV_TESTED; 407 redirect(n->nredir.redirect, 0); 408 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 409 } 410 if (! backgnd) { 411 INTOFF; 412 exitstatus = waitforjob(jp); 413 INTON; 414 } 415 } 416 417 418 419 /* 420 * Compute the names of the files in a redirection list. 421 */ 422 423 STATIC void 424 expredir(n) 425 union node *n; 426 { 427 register union node *redir; 428 429 for (redir = n ; redir ; redir = redir->nfile.next) { 430 struct arglist fn; 431 fn.lastp = &fn.list; 432 oexitstatus = exitstatus; 433 switch (redir->type) { 434 case NFROM: 435 case NTO: 436 case NAPPEND: 437 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 438 redir->nfile.expfname = fn.list->text; 439 break; 440 case NFROMFD: 441 case NTOFD: 442 if (redir->ndup.vname) { 443 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 444 fixredir(redir, fn.list->text, 1); 445 } 446 break; 447 } 448 } 449 } 450 451 452 453 /* 454 * Evaluate a pipeline. All the processes in the pipeline are children 455 * of the process creating the pipeline. (This differs from some versions 456 * of the shell, which make the last process in a pipeline the parent 457 * of all the rest.) 458 */ 459 460 STATIC void 461 evalpipe(n) 462 union node *n; 463 { 464 struct job *jp; 465 struct nodelist *lp; 466 int pipelen; 467 int prevfd; 468 int pip[2]; 469 470 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 471 pipelen = 0; 472 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 473 pipelen++; 474 INTOFF; 475 jp = makejob(n, pipelen); 476 prevfd = -1; 477 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 478 prehash(lp->n); 479 pip[1] = -1; 480 if (lp->next) { 481 if (pipe(pip) < 0) { 482 close(prevfd); 483 error("Pipe call failed"); 484 } 485 } 486 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 487 INTON; 488 if (prevfd > 0) { 489 close(0); 490 copyfd(prevfd, 0); 491 close(prevfd); 492 } 493 if (pip[1] >= 0) { 494 close(pip[0]); 495 if (pip[1] != 1) { 496 close(1); 497 copyfd(pip[1], 1); 498 close(pip[1]); 499 } 500 } 501 evaltree(lp->n, EV_EXIT); 502 } 503 if (prevfd >= 0) 504 close(prevfd); 505 prevfd = pip[0]; 506 close(pip[1]); 507 } 508 INTON; 509 if (n->npipe.backgnd == 0) { 510 INTOFF; 511 exitstatus = waitforjob(jp); 512 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 513 INTON; 514 } 515 } 516 517 518 519 /* 520 * Execute a command inside back quotes. If it's a builtin command, we 521 * want to save its output in a block obtained from malloc. Otherwise 522 * we fork off a subprocess and get the output of the command via a pipe. 523 * Should be called with interrupts off. 524 */ 525 526 void 527 evalbackcmd(n, result) 528 union node *n; 529 struct backcmd *result; 530 { 531 int pip[2]; 532 struct job *jp; 533 struct stackmark smark; /* unnecessary */ 534 535 setstackmark(&smark); 536 result->fd = -1; 537 result->buf = NULL; 538 result->nleft = 0; 539 result->jp = NULL; 540 if (n == NULL) { 541 exitstatus = 0; 542 goto out; 543 } 544 if (n->type == NCMD) { 545 exitstatus = oexitstatus; 546 evalcommand(n, EV_BACKCMD, result); 547 } else { 548 exitstatus = 0; 549 if (pipe(pip) < 0) 550 error("Pipe call failed"); 551 jp = makejob(n, 1); 552 if (forkshell(jp, n, FORK_NOJOB) == 0) { 553 FORCEINTON; 554 close(pip[0]); 555 if (pip[1] != 1) { 556 close(1); 557 copyfd(pip[1], 1); 558 close(pip[1]); 559 } 560 evaltree(n, EV_EXIT); 561 } 562 close(pip[1]); 563 result->fd = pip[0]; 564 result->jp = jp; 565 } 566 out: 567 popstackmark(&smark); 568 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 569 result->fd, result->buf, result->nleft, result->jp)); 570 } 571 572 573 574 /* 575 * Execute a simple command. 576 */ 577 578 STATIC void 579 evalcommand(cmd, flags, backcmd) 580 union node *cmd; 581 int flags; 582 struct backcmd *backcmd; 583 { 584 struct stackmark smark; 585 union node *argp; 586 struct arglist arglist; 587 struct arglist varlist; 588 char **argv; 589 int argc; 590 char **envp; 591 int varflag; 592 struct strlist *sp; 593 int mode; 594 int pip[2]; 595 struct cmdentry cmdentry; 596 struct job *jp; 597 struct jmploc jmploc; 598 struct jmploc *volatile savehandler; 599 char *volatile savecmdname; 600 volatile struct shparam saveparam; 601 struct localvar *volatile savelocalvars; 602 volatile int e; 603 char *lastarg; 604 #if __GNUC__ 605 /* Avoid longjmp clobbering */ 606 (void) &argv; 607 (void) &argc; 608 (void) &lastarg; 609 (void) &flags; 610 #endif 611 612 /* First expand the arguments. */ 613 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 614 setstackmark(&smark); 615 arglist.lastp = &arglist.list; 616 varlist.lastp = &varlist.list; 617 varflag = 1; 618 oexitstatus = exitstatus; 619 exitstatus = 0; 620 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 621 char *p = argp->narg.text; 622 if (varflag && is_name(*p)) { 623 do { 624 p++; 625 } while (is_in_name(*p)); 626 if (*p == '=') { 627 expandarg(argp, &varlist, EXP_VARTILDE); 628 continue; 629 } 630 } 631 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 632 varflag = 0; 633 } 634 *arglist.lastp = NULL; 635 *varlist.lastp = NULL; 636 expredir(cmd->ncmd.redirect); 637 argc = 0; 638 for (sp = arglist.list ; sp ; sp = sp->next) 639 argc++; 640 argv = stalloc(sizeof (char *) * (argc + 1)); 641 642 for (sp = arglist.list ; sp ; sp = sp->next) { 643 TRACE(("evalcommand arg: %s\n", sp->text)); 644 *argv++ = sp->text; 645 } 646 *argv = NULL; 647 lastarg = NULL; 648 if (iflag && funcnest == 0 && argc > 0) 649 lastarg = argv[-1]; 650 argv -= argc; 651 652 /* Print the command if xflag is set. */ 653 if (xflag) { 654 outc('+', &errout); 655 for (sp = varlist.list ; sp ; sp = sp->next) { 656 outc(' ', &errout); 657 out2str(sp->text); 658 } 659 for (sp = arglist.list ; sp ; sp = sp->next) { 660 outc(' ', &errout); 661 out2str(sp->text); 662 } 663 outc('\n', &errout); 664 flushout(&errout); 665 } 666 667 /* Now locate the command. */ 668 if (argc == 0) { 669 cmdentry.cmdtype = CMDBUILTIN; 670 cmdentry.u.index = BLTINCMD; 671 } else { 672 static const char PATH[] = "PATH="; 673 char *path = pathval(); 674 675 /* 676 * Modify the command lookup path, if a PATH= assignment 677 * is present 678 */ 679 for (sp = varlist.list ; sp ; sp = sp->next) 680 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) 681 path = sp->text + sizeof(PATH) - 1; 682 683 find_command(argv[0], &cmdentry, 1, path); 684 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 685 exitstatus = 1; 686 flushout(&errout); 687 return; 688 } 689 /* implement the bltin builtin here */ 690 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 691 for (;;) { 692 argv++; 693 if (--argc == 0) 694 break; 695 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 696 outfmt(&errout, "%s: not found\n", *argv); 697 exitstatus = 1; 698 flushout(&errout); 699 return; 700 } 701 if (cmdentry.u.index != BLTINCMD) 702 break; 703 } 704 } 705 } 706 707 /* Fork off a child process if necessary. */ 708 if (cmd->ncmd.backgnd 709 || (cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0) 710 || ((flags & EV_BACKCMD) != 0 711 && (cmdentry.cmdtype != CMDBUILTIN 712 || cmdentry.u.index == DOTCMD 713 || cmdentry.u.index == EVALCMD))) { 714 jp = makejob(cmd, 1); 715 mode = cmd->ncmd.backgnd; 716 if (flags & EV_BACKCMD) { 717 mode = FORK_NOJOB; 718 if (pipe(pip) < 0) 719 error("Pipe call failed"); 720 } 721 if (forkshell(jp, cmd, mode) != 0) 722 goto parent; /* at end of routine */ 723 if (flags & EV_BACKCMD) { 724 FORCEINTON; 725 close(pip[0]); 726 if (pip[1] != 1) { 727 close(1); 728 copyfd(pip[1], 1); 729 close(pip[1]); 730 } 731 } 732 flags |= EV_EXIT; 733 } 734 735 /* This is the child process if a fork occurred. */ 736 /* Execute the command. */ 737 if (cmdentry.cmdtype == CMDFUNCTION) { 738 trputs("Shell function: "); trargs(argv); 739 redirect(cmd->ncmd.redirect, REDIR_PUSH); 740 saveparam = shellparam; 741 shellparam.malloc = 0; 742 shellparam.nparam = argc - 1; 743 shellparam.p = argv + 1; 744 shellparam.optnext = NULL; 745 INTOFF; 746 savelocalvars = localvars; 747 localvars = NULL; 748 INTON; 749 if (setjmp(jmploc.loc)) { 750 if (exception == EXSHELLPROC) 751 freeparam((struct shparam *)&saveparam); 752 else { 753 freeparam(&shellparam); 754 shellparam = saveparam; 755 } 756 poplocalvars(); 757 localvars = savelocalvars; 758 handler = savehandler; 759 longjmp(handler->loc, 1); 760 } 761 savehandler = handler; 762 handler = &jmploc; 763 for (sp = varlist.list ; sp ; sp = sp->next) 764 mklocal(sp->text); 765 funcnest++; 766 evaltree(cmdentry.u.func, 0); 767 funcnest--; 768 INTOFF; 769 poplocalvars(); 770 localvars = savelocalvars; 771 freeparam(&shellparam); 772 shellparam = saveparam; 773 handler = savehandler; 774 popredir(); 775 INTON; 776 if (evalskip == SKIPFUNC) { 777 evalskip = 0; 778 skipcount = 0; 779 } 780 if (flags & EV_EXIT) 781 exitshell(exitstatus); 782 } else if (cmdentry.cmdtype == CMDBUILTIN) { 783 trputs("builtin command: "); trargs(argv); 784 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 785 if (flags == EV_BACKCMD) { 786 memout.nleft = 0; 787 memout.nextc = memout.buf; 788 memout.bufsize = 64; 789 mode |= REDIR_BACKQ; 790 } 791 redirect(cmd->ncmd.redirect, mode); 792 savecmdname = commandname; 793 cmdenviron = varlist.list; 794 e = -1; 795 if (setjmp(jmploc.loc)) { 796 e = exception; 797 exitstatus = (e == EXINT)? SIGINT+128 : 2; 798 goto cmddone; 799 } 800 savehandler = handler; 801 handler = &jmploc; 802 commandname = argv[0]; 803 argptr = argv + 1; 804 optptr = NULL; /* initialize nextopt */ 805 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 806 flushall(); 807 cmddone: 808 out1 = &output; 809 out2 = &errout; 810 freestdout(); 811 if (e != EXSHELLPROC) { 812 commandname = savecmdname; 813 if (flags & EV_EXIT) { 814 exitshell(exitstatus); 815 } 816 } 817 handler = savehandler; 818 if (e != -1) { 819 if (e != EXERROR || cmdentry.u.index == BLTINCMD 820 || cmdentry.u.index == DOTCMD 821 || cmdentry.u.index == EVALCMD 822 #ifndef NO_HISTORY 823 || cmdentry.u.index == HISTCMD 824 #endif 825 || cmdentry.u.index == EXECCMD) 826 exraise(e); 827 FORCEINTON; 828 } 829 if (cmdentry.u.index != EXECCMD) 830 popredir(); 831 if (flags == EV_BACKCMD) { 832 backcmd->buf = memout.buf; 833 backcmd->nleft = memout.nextc - memout.buf; 834 memout.buf = NULL; 835 } 836 } else { 837 trputs("normal command: "); trargs(argv); 838 clearredir(); 839 redirect(cmd->ncmd.redirect, 0); 840 for (sp = varlist.list ; sp ; sp = sp->next) 841 setvareq(sp->text, VEXPORT|VSTACK); 842 envp = environment(); 843 shellexec(argv, envp, pathval(), cmdentry.u.index); 844 /*NOTREACHED*/ 845 } 846 goto out; 847 848 parent: /* parent process gets here (if we forked) */ 849 if (mode == 0) { /* argument to fork */ 850 INTOFF; 851 exitstatus = waitforjob(jp); 852 INTON; 853 } else if (mode == 2) { 854 backcmd->fd = pip[0]; 855 close(pip[1]); 856 backcmd->jp = jp; 857 } 858 859 out: 860 if (lastarg) 861 setvar("_", lastarg, 0); 862 popstackmark(&smark); 863 } 864 865 866 867 /* 868 * Search for a command. This is called before we fork so that the 869 * location of the command will be available in the parent as well as 870 * the child. The check for "goodname" is an overly conservative 871 * check that the name will not be subject to expansion. 872 */ 873 874 STATIC void 875 prehash(n) 876 union node *n; 877 { 878 struct cmdentry entry; 879 880 if (n->type == NCMD && n->ncmd.args) 881 if (goodname(n->ncmd.args->narg.text)) 882 find_command(n->ncmd.args->narg.text, &entry, 0, 883 pathval()); 884 } 885 886 887 888 /* 889 * Builtin commands. Builtin commands whose functions are closely 890 * tied to evaluation are implemented here. 891 */ 892 893 /* 894 * No command given, or a bltin command with no arguments. Set the 895 * specified variables. 896 */ 897 898 int 899 bltincmd(argc, argv) 900 int argc; 901 char **argv; 902 { 903 listsetvar(cmdenviron); 904 /* 905 * Preserve exitstatus of a previous possible redirection 906 * as POSIX mandates 907 */ 908 return exitstatus; 909 } 910 911 912 /* 913 * Handle break and continue commands. Break, continue, and return are 914 * all handled by setting the evalskip flag. The evaluation routines 915 * above all check this flag, and if it is set they start skipping 916 * commands rather than executing them. The variable skipcount is 917 * the number of loops to break/continue, or the number of function 918 * levels to return. (The latter is always 1.) It should probably 919 * be an error to break out of more loops than exist, but it isn't 920 * in the standard shell so we don't make it one here. 921 */ 922 923 int 924 breakcmd(argc, argv) 925 int argc; 926 char **argv; 927 { 928 int n = argc > 1 ? number(argv[1]) : 1; 929 930 if (n > loopnest) 931 n = loopnest; 932 if (n > 0) { 933 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 934 skipcount = n; 935 } 936 return 0; 937 } 938 939 940 /* 941 * The return command. 942 */ 943 944 int 945 returncmd(argc, argv) 946 int argc; 947 char **argv; 948 { 949 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 950 951 if (funcnest) { 952 evalskip = SKIPFUNC; 953 skipcount = 1; 954 return ret; 955 } 956 else { 957 /* Do what ksh does; skip the rest of the file */ 958 evalskip = SKIPFILE; 959 skipcount = 1; 960 return ret; 961 } 962 } 963 964 965 int 966 falsecmd(argc, argv) 967 int argc; 968 char **argv; 969 { 970 return 1; 971 } 972 973 974 int 975 truecmd(argc, argv) 976 int argc; 977 char **argv; 978 { 979 return 0; 980 } 981 982 983 int 984 execcmd(argc, argv) 985 int argc; 986 char **argv; 987 { 988 if (argc > 1) { 989 struct strlist *sp; 990 991 iflag = 0; /* exit on error */ 992 mflag = 0; 993 optschanged(); 994 for (sp = cmdenviron; sp ; sp = sp->next) 995 setvareq(sp->text, VEXPORT|VSTACK); 996 shellexec(argv + 1, environment(), pathval(), 0); 997 998 } 999 return 0; 1000 } 1001