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 1.4 1995/09/20 08:30:56 davidg Exp $ 37 */ 38 39 #ifndef lint 40 static char 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 80 /* reasons for skipping commands (see comment on breakcmd routine) */ 81 #define SKIPBREAK 1 82 #define SKIPCONT 2 83 #define SKIPFUNC 3 84 85 MKINIT int evalskip; /* set if we are skipping commands */ 86 STATIC int skipcount; /* number of levels to skip */ 87 MKINIT int loopnest; /* current loop nesting level */ 88 int funcnest; /* depth of function calls */ 89 90 91 char *commandname; 92 struct strlist *cmdenviron; 93 int exitstatus; /* exit status of last command */ 94 int oexitstatus; /* saved exit status */ 95 96 97 STATIC void evalloop __P((union node *)); 98 STATIC void evalfor __P((union node *)); 99 STATIC void evalcase __P((union node *, int)); 100 STATIC void evalsubshell __P((union node *, int)); 101 STATIC void expredir __P((union node *)); 102 STATIC void evalpipe __P((union node *)); 103 STATIC void evalcommand __P((union node *, int, struct backcmd *)); 104 STATIC void prehash __P((union node *)); 105 106 107 /* 108 * Called to reset things after an exception. 109 */ 110 111 #ifdef mkinit 112 INCLUDE "eval.h" 113 114 RESET { 115 evalskip = 0; 116 loopnest = 0; 117 funcnest = 0; 118 } 119 120 SHELLPROC { 121 exitstatus = 0; 122 } 123 #endif 124 125 126 127 /* 128 * The eval commmand. 129 */ 130 131 int 132 evalcmd(argc, argv) 133 int argc; 134 char **argv; 135 { 136 char *p; 137 char *concat; 138 char **ap; 139 140 if (argc > 1) { 141 p = argv[1]; 142 if (argc > 2) { 143 STARTSTACKSTR(concat); 144 ap = argv + 2; 145 for (;;) { 146 while (*p) 147 STPUTC(*p++, concat); 148 if ((p = *ap++) == NULL) 149 break; 150 STPUTC(' ', concat); 151 } 152 STPUTC('\0', concat); 153 p = grabstackstr(concat); 154 } 155 evalstring(p); 156 } 157 return exitstatus; 158 } 159 160 161 /* 162 * Execute a command or commands contained in a string. 163 */ 164 165 void 166 evalstring(s) 167 char *s; 168 { 169 union node *n; 170 struct stackmark smark; 171 172 setstackmark(&smark); 173 setinputstring(s, 1); 174 while ((n = parsecmd(0)) != NEOF) { 175 evaltree(n, 0); 176 popstackmark(&smark); 177 } 178 popfile(); 179 popstackmark(&smark); 180 } 181 182 183 184 /* 185 * Evaluate a parse tree. The value is left in the global variable 186 * exitstatus. 187 */ 188 189 void 190 evaltree(n, flags) 191 union node *n; 192 int flags; 193 { 194 if (n == NULL) { 195 TRACE(("evaltree(NULL) called\n")); 196 exitstatus = 0; 197 goto out; 198 } 199 #ifndef NO_HISTORY 200 displayhist = 1; /* show history substitutions done with fc */ 201 #endif 202 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type)); 203 switch (n->type) { 204 case NSEMI: 205 evaltree(n->nbinary.ch1, 0); 206 if (evalskip) 207 goto out; 208 evaltree(n->nbinary.ch2, flags); 209 break; 210 case NAND: 211 evaltree(n->nbinary.ch1, EV_TESTED); 212 if (evalskip || exitstatus != 0) 213 goto out; 214 evaltree(n->nbinary.ch2, flags); 215 break; 216 case NOR: 217 evaltree(n->nbinary.ch1, EV_TESTED); 218 if (evalskip || exitstatus == 0) 219 goto out; 220 evaltree(n->nbinary.ch2, flags); 221 break; 222 case NREDIR: 223 expredir(n->nredir.redirect); 224 redirect(n->nredir.redirect, REDIR_PUSH); 225 evaltree(n->nredir.n, flags); 226 popredir(); 227 break; 228 case NSUBSHELL: 229 evalsubshell(n, flags); 230 break; 231 case NBACKGND: 232 evalsubshell(n, flags); 233 break; 234 case NIF: { 235 int status; 236 237 evaltree(n->nif.test, EV_TESTED); 238 status = exitstatus; 239 exitstatus = 0; 240 if (evalskip) 241 goto out; 242 if (status == 0) 243 evaltree(n->nif.ifpart, flags); 244 else if (n->nif.elsepart) 245 evaltree(n->nif.elsepart, flags); 246 break; 247 } 248 case NWHILE: 249 case NUNTIL: 250 evalloop(n); 251 break; 252 case NFOR: 253 evalfor(n); 254 break; 255 case NCASE: 256 evalcase(n, flags); 257 break; 258 case NDEFUN: 259 defun(n->narg.text, n->narg.next); 260 exitstatus = 0; 261 break; 262 case NNOT: 263 evaltree(n->nnot.com, EV_TESTED); 264 exitstatus = !exitstatus; 265 break; 266 267 case NPIPE: 268 evalpipe(n); 269 break; 270 case NCMD: 271 evalcommand(n, flags, (struct backcmd *)NULL); 272 break; 273 default: 274 out1fmt("Node type = %d\n", n->type); 275 flushout(&output); 276 break; 277 } 278 out: 279 if (pendingsigs) 280 dotrap(); 281 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 282 exitshell(exitstatus); 283 } 284 285 286 STATIC void 287 evalloop(n) 288 union node *n; 289 { 290 int status; 291 292 loopnest++; 293 status = 0; 294 for (;;) { 295 evaltree(n->nbinary.ch1, EV_TESTED); 296 if (evalskip) { 297 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 298 evalskip = 0; 299 continue; 300 } 301 if (evalskip == SKIPBREAK && --skipcount <= 0) 302 evalskip = 0; 303 break; 304 } 305 if (n->type == NWHILE) { 306 if (exitstatus != 0) 307 break; 308 } else { 309 if (exitstatus == 0) 310 break; 311 } 312 evaltree(n->nbinary.ch2, 0); 313 status = exitstatus; 314 if (evalskip) 315 goto skipping; 316 } 317 loopnest--; 318 exitstatus = status; 319 } 320 321 322 323 STATIC void 324 evalfor(n) 325 union node *n; 326 { 327 struct arglist arglist; 328 union node *argp; 329 struct strlist *sp; 330 struct stackmark smark; 331 332 setstackmark(&smark); 333 arglist.lastp = &arglist.list; 334 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 335 oexitstatus = exitstatus; 336 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 337 if (evalskip) 338 goto out; 339 } 340 *arglist.lastp = NULL; 341 342 exitstatus = 0; 343 loopnest++; 344 for (sp = arglist.list ; sp ; sp = sp->next) { 345 setvar(n->nfor.var, sp->text, 0); 346 evaltree(n->nfor.body, 0); 347 if (evalskip) { 348 if (evalskip == SKIPCONT && --skipcount <= 0) { 349 evalskip = 0; 350 continue; 351 } 352 if (evalskip == SKIPBREAK && --skipcount <= 0) 353 evalskip = 0; 354 break; 355 } 356 } 357 loopnest--; 358 out: 359 popstackmark(&smark); 360 } 361 362 363 364 STATIC void 365 evalcase(n, flags) 366 union node *n; 367 int flags; 368 { 369 union node *cp; 370 union node *patp; 371 struct arglist arglist; 372 struct stackmark smark; 373 374 setstackmark(&smark); 375 arglist.lastp = &arglist.list; 376 oexitstatus = exitstatus; 377 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 378 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 379 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 380 if (casematch(patp, arglist.list->text)) { 381 if (evalskip == 0) { 382 evaltree(cp->nclist.body, flags); 383 } 384 goto out; 385 } 386 } 387 } 388 out: 389 popstackmark(&smark); 390 } 391 392 393 394 /* 395 * Kick off a subshell to evaluate a tree. 396 */ 397 398 STATIC void 399 evalsubshell(n, flags) 400 union node *n; 401 int flags; 402 { 403 struct job *jp; 404 int backgnd = (n->type == NBACKGND); 405 406 expredir(n->nredir.redirect); 407 jp = makejob(n, 1); 408 if (forkshell(jp, n, backgnd) == 0) { 409 if (backgnd) 410 flags &=~ EV_TESTED; 411 redirect(n->nredir.redirect, 0); 412 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 413 } 414 if (! backgnd) { 415 INTOFF; 416 exitstatus = waitforjob(jp); 417 INTON; 418 } 419 } 420 421 422 423 /* 424 * Compute the names of the files in a redirection list. 425 */ 426 427 STATIC void 428 expredir(n) 429 union node *n; 430 { 431 register union node *redir; 432 433 for (redir = n ; redir ; redir = redir->nfile.next) { 434 struct arglist fn; 435 fn.lastp = &fn.list; 436 oexitstatus = exitstatus; 437 switch (redir->type) { 438 case NFROM: 439 case NTO: 440 case NAPPEND: 441 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 442 redir->nfile.expfname = fn.list->text; 443 break; 444 case NFROMFD: 445 case NTOFD: 446 if (redir->ndup.vname) { 447 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 448 fixredir(redir, fn.list->text, 1); 449 } 450 break; 451 } 452 } 453 } 454 455 456 457 /* 458 * Evaluate a pipeline. All the processes in the pipeline are children 459 * of the process creating the pipeline. (This differs from some versions 460 * of the shell, which make the last process in a pipeline the parent 461 * of all the rest.) 462 */ 463 464 STATIC void 465 evalpipe(n) 466 union node *n; 467 { 468 struct job *jp; 469 struct nodelist *lp; 470 int pipelen; 471 int prevfd; 472 int pip[2]; 473 474 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 475 pipelen = 0; 476 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 477 pipelen++; 478 INTOFF; 479 jp = makejob(n, pipelen); 480 prevfd = -1; 481 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 482 prehash(lp->n); 483 pip[1] = -1; 484 if (lp->next) { 485 if (pipe(pip) < 0) { 486 close(prevfd); 487 error("Pipe call failed"); 488 } 489 } 490 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 491 INTON; 492 if (prevfd > 0) { 493 close(0); 494 copyfd(prevfd, 0); 495 close(prevfd); 496 } 497 if (pip[1] >= 0) { 498 close(pip[0]); 499 if (pip[1] != 1) { 500 close(1); 501 copyfd(pip[1], 1); 502 close(pip[1]); 503 } 504 } 505 evaltree(lp->n, EV_EXIT); 506 } 507 if (prevfd >= 0) 508 close(prevfd); 509 prevfd = pip[0]; 510 close(pip[1]); 511 } 512 INTON; 513 if (n->npipe.backgnd == 0) { 514 INTOFF; 515 exitstatus = waitforjob(jp); 516 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 517 INTON; 518 } 519 } 520 521 522 523 /* 524 * Execute a command inside back quotes. If it's a builtin command, we 525 * want to save its output in a block obtained from malloc. Otherwise 526 * we fork off a subprocess and get the output of the command via a pipe. 527 * Should be called with interrupts off. 528 */ 529 530 void 531 evalbackcmd(n, result) 532 union node *n; 533 struct backcmd *result; 534 { 535 int pip[2]; 536 struct job *jp; 537 struct stackmark smark; /* unnecessary */ 538 539 setstackmark(&smark); 540 result->fd = -1; 541 result->buf = NULL; 542 result->nleft = 0; 543 result->jp = NULL; 544 if (n == NULL) { 545 exitstatus = 0; 546 goto out; 547 } 548 if (n->type == NCMD) { 549 exitstatus = oexitstatus; 550 evalcommand(n, EV_BACKCMD, result); 551 } else { 552 exitstatus = 0; 553 if (pipe(pip) < 0) 554 error("Pipe call failed"); 555 jp = makejob(n, 1); 556 if (forkshell(jp, n, FORK_NOJOB) == 0) { 557 FORCEINTON; 558 close(pip[0]); 559 if (pip[1] != 1) { 560 close(1); 561 copyfd(pip[1], 1); 562 close(pip[1]); 563 } 564 evaltree(n, EV_EXIT); 565 } 566 close(pip[1]); 567 result->fd = pip[0]; 568 result->jp = jp; 569 } 570 out: 571 popstackmark(&smark); 572 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 573 result->fd, result->buf, result->nleft, result->jp)); 574 } 575 576 577 578 /* 579 * Execute a simple command. 580 */ 581 582 STATIC void 583 evalcommand(cmd, flags, backcmd) 584 union node *cmd; 585 int flags; 586 struct backcmd *backcmd; 587 { 588 struct stackmark smark; 589 union node *argp; 590 struct arglist arglist; 591 struct arglist varlist; 592 char **argv; 593 int argc; 594 char **envp; 595 int varflag; 596 struct strlist *sp; 597 int mode; 598 int pip[2]; 599 struct cmdentry cmdentry; 600 struct job *jp; 601 struct jmploc jmploc; 602 struct jmploc *volatile savehandler; 603 char *volatile savecmdname; 604 volatile struct shparam saveparam; 605 struct localvar *volatile savelocalvars; 606 volatile int e; 607 char *lastarg; 608 #if __GNUC__ 609 /* Avoid longjmp clobbering */ 610 (void) &argv; 611 (void) &argc; 612 (void) &lastarg; 613 (void) &flags; 614 #endif 615 616 /* First expand the arguments. */ 617 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 618 setstackmark(&smark); 619 arglist.lastp = &arglist.list; 620 varlist.lastp = &varlist.list; 621 varflag = 1; 622 oexitstatus = exitstatus; 623 exitstatus = 0; 624 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 625 char *p = argp->narg.text; 626 if (varflag && is_name(*p)) { 627 do { 628 p++; 629 } while (is_in_name(*p)); 630 if (*p == '=') { 631 expandarg(argp, &varlist, EXP_VARTILDE); 632 continue; 633 } 634 } 635 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 636 varflag = 0; 637 } 638 *arglist.lastp = NULL; 639 *varlist.lastp = NULL; 640 expredir(cmd->ncmd.redirect); 641 argc = 0; 642 for (sp = arglist.list ; sp ; sp = sp->next) 643 argc++; 644 argv = stalloc(sizeof (char *) * (argc + 1)); 645 646 for (sp = arglist.list ; sp ; sp = sp->next) { 647 TRACE(("evalcommand arg: %s\n", sp->text)); 648 *argv++ = sp->text; 649 } 650 *argv = NULL; 651 lastarg = NULL; 652 if (iflag && funcnest == 0 && argc > 0) 653 lastarg = argv[-1]; 654 argv -= argc; 655 656 /* Print the command if xflag is set. */ 657 if (xflag) { 658 outc('+', &errout); 659 for (sp = varlist.list ; sp ; sp = sp->next) { 660 outc(' ', &errout); 661 out2str(sp->text); 662 } 663 for (sp = arglist.list ; sp ; sp = sp->next) { 664 outc(' ', &errout); 665 out2str(sp->text); 666 } 667 outc('\n', &errout); 668 flushout(&errout); 669 } 670 671 /* Now locate the command. */ 672 if (argc == 0) { 673 cmdentry.cmdtype = CMDBUILTIN; 674 cmdentry.u.index = BLTINCMD; 675 } else { 676 static const char PATH[] = "PATH="; 677 char *path = pathval(); 678 679 /* 680 * Modify the command lookup path, if a PATH= assignment 681 * is present 682 */ 683 for (sp = varlist.list ; sp ; sp = sp->next) 684 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) 685 path = sp->text + sizeof(PATH) - 1; 686 687 find_command(argv[0], &cmdentry, 1, path); 688 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 689 exitstatus = 1; 690 flushout(&errout); 691 return; 692 } 693 /* implement the bltin builtin here */ 694 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 695 for (;;) { 696 argv++; 697 if (--argc == 0) 698 break; 699 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 700 outfmt(&errout, "%s: not found\n", *argv); 701 exitstatus = 1; 702 flushout(&errout); 703 return; 704 } 705 if (cmdentry.u.index != BLTINCMD) 706 break; 707 } 708 } 709 } 710 711 /* Fork off a child process if necessary. */ 712 if (cmd->ncmd.backgnd 713 || (cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0) 714 || ((flags & EV_BACKCMD) != 0 715 && (cmdentry.cmdtype != CMDBUILTIN 716 || cmdentry.u.index == DOTCMD 717 || cmdentry.u.index == EVALCMD))) { 718 jp = makejob(cmd, 1); 719 mode = cmd->ncmd.backgnd; 720 if (flags & EV_BACKCMD) { 721 mode = FORK_NOJOB; 722 if (pipe(pip) < 0) 723 error("Pipe call failed"); 724 } 725 if (forkshell(jp, cmd, mode) != 0) 726 goto parent; /* at end of routine */ 727 if (flags & EV_BACKCMD) { 728 FORCEINTON; 729 close(pip[0]); 730 if (pip[1] != 1) { 731 close(1); 732 copyfd(pip[1], 1); 733 close(pip[1]); 734 } 735 } 736 flags |= EV_EXIT; 737 } 738 739 /* This is the child process if a fork occurred. */ 740 /* Execute the command. */ 741 if (cmdentry.cmdtype == CMDFUNCTION) { 742 trputs("Shell function: "); trargs(argv); 743 redirect(cmd->ncmd.redirect, REDIR_PUSH); 744 saveparam = shellparam; 745 shellparam.malloc = 0; 746 shellparam.nparam = argc - 1; 747 shellparam.p = argv + 1; 748 shellparam.optnext = NULL; 749 INTOFF; 750 savelocalvars = localvars; 751 localvars = NULL; 752 INTON; 753 if (setjmp(jmploc.loc)) { 754 if (exception == EXSHELLPROC) 755 freeparam((struct shparam *)&saveparam); 756 else { 757 freeparam(&shellparam); 758 shellparam = saveparam; 759 } 760 poplocalvars(); 761 localvars = savelocalvars; 762 handler = savehandler; 763 longjmp(handler->loc, 1); 764 } 765 savehandler = handler; 766 handler = &jmploc; 767 for (sp = varlist.list ; sp ; sp = sp->next) 768 mklocal(sp->text); 769 funcnest++; 770 evaltree(cmdentry.u.func, 0); 771 funcnest--; 772 INTOFF; 773 poplocalvars(); 774 localvars = savelocalvars; 775 freeparam(&shellparam); 776 shellparam = saveparam; 777 handler = savehandler; 778 popredir(); 779 INTON; 780 if (evalskip == SKIPFUNC) { 781 evalskip = 0; 782 skipcount = 0; 783 } 784 if (flags & EV_EXIT) 785 exitshell(exitstatus); 786 } else if (cmdentry.cmdtype == CMDBUILTIN) { 787 trputs("builtin command: "); trargs(argv); 788 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 789 if (flags == EV_BACKCMD) { 790 memout.nleft = 0; 791 memout.nextc = memout.buf; 792 memout.bufsize = 64; 793 mode |= REDIR_BACKQ; 794 } 795 redirect(cmd->ncmd.redirect, mode); 796 savecmdname = commandname; 797 cmdenviron = varlist.list; 798 e = -1; 799 if (setjmp(jmploc.loc)) { 800 e = exception; 801 exitstatus = (e == EXINT)? SIGINT+128 : 2; 802 goto cmddone; 803 } 804 savehandler = handler; 805 handler = &jmploc; 806 commandname = argv[0]; 807 argptr = argv + 1; 808 optptr = NULL; /* initialize nextopt */ 809 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 810 flushall(); 811 cmddone: 812 out1 = &output; 813 out2 = &errout; 814 freestdout(); 815 if (e != EXSHELLPROC) { 816 commandname = savecmdname; 817 if (flags & EV_EXIT) { 818 exitshell(exitstatus); 819 } 820 } 821 handler = savehandler; 822 if (e != -1) { 823 if (e != EXERROR || 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 trputs("normal command: "); trargs(argv); 842 clearredir(); 843 redirect(cmd->ncmd.redirect, 0); 844 for (sp = varlist.list ; sp ; sp = sp->next) 845 setvareq(sp->text, VEXPORT|VSTACK); 846 envp = environment(); 847 shellexec(argv, envp, pathval(), cmdentry.u.index); 848 /*NOTREACHED*/ 849 } 850 goto out; 851 852 parent: /* parent process gets here (if we forked) */ 853 if (mode == 0) { /* argument to fork */ 854 INTOFF; 855 exitstatus = waitforjob(jp); 856 INTON; 857 } else if (mode == 2) { 858 backcmd->fd = pip[0]; 859 close(pip[1]); 860 backcmd->jp = jp; 861 } 862 863 out: 864 if (lastarg) 865 setvar("_", lastarg, 0); 866 popstackmark(&smark); 867 } 868 869 870 871 /* 872 * Search for a command. This is called before we fork so that the 873 * location of the command will be available in the parent as well as 874 * the child. The check for "goodname" is an overly conservative 875 * check that the name will not be subject to expansion. 876 */ 877 878 STATIC void 879 prehash(n) 880 union node *n; 881 { 882 struct cmdentry entry; 883 884 if (n->type == NCMD && n->ncmd.args) 885 if (goodname(n->ncmd.args->narg.text)) 886 find_command(n->ncmd.args->narg.text, &entry, 0, 887 pathval()); 888 } 889 890 891 892 /* 893 * Builtin commands. Builtin commands whose functions are closely 894 * tied to evaluation are implemented here. 895 */ 896 897 /* 898 * No command given, or a bltin command with no arguments. Set the 899 * specified variables. 900 */ 901 902 int 903 bltincmd(argc, argv) 904 int argc; 905 char **argv; 906 { 907 listsetvar(cmdenviron); 908 /* 909 * Preserve exitstatus of a previous possible redirection 910 * as POSIX mandates 911 */ 912 return exitstatus; 913 } 914 915 916 /* 917 * Handle break and continue commands. Break, continue, and return are 918 * all handled by setting the evalskip flag. The evaluation routines 919 * above all check this flag, and if it is set they start skipping 920 * commands rather than executing them. The variable skipcount is 921 * the number of loops to break/continue, or the number of function 922 * levels to return. (The latter is always 1.) It should probably 923 * be an error to break out of more loops than exist, but it isn't 924 * in the standard shell so we don't make it one here. 925 */ 926 927 int 928 breakcmd(argc, argv) 929 int argc; 930 char **argv; 931 { 932 int n; 933 934 n = 1; 935 if (argc > 1) 936 n = number(argv[1]); 937 if (n > loopnest) 938 n = loopnest; 939 if (n > 0) { 940 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 941 skipcount = n; 942 } 943 return 0; 944 } 945 946 947 /* 948 * The return command. 949 */ 950 951 int 952 returncmd(argc, argv) 953 int argc; 954 char **argv; 955 { 956 int ret; 957 958 ret = exitstatus; 959 if (argc > 1) 960 ret = number(argv[1]); 961 if (funcnest) { 962 evalskip = SKIPFUNC; 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