1 /* $NetBSD: eval.c,v 1.57 2001/02/04 19:52:06 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 #include <sys/cdefs.h> 40 #ifndef lint 41 #if 0 42 static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 43 #else 44 __RCSID("$NetBSD: eval.c,v 1.57 2001/02/04 19:52:06 christos Exp $"); 45 #endif 46 #endif /* not lint */ 47 48 #include <signal.h> 49 #include <unistd.h> 50 51 /* 52 * Evaluate a command. 53 */ 54 55 #include "shell.h" 56 #include "nodes.h" 57 #include "syntax.h" 58 #include "expand.h" 59 #include "parser.h" 60 #include "jobs.h" 61 #include "eval.h" 62 #include "builtins.h" 63 #include "options.h" 64 #include "exec.h" 65 #include "redir.h" 66 #include "input.h" 67 #include "output.h" 68 #include "trap.h" 69 #include "var.h" 70 #include "memalloc.h" 71 #include "error.h" 72 #include "show.h" 73 #include "mystring.h" 74 #ifndef SMALL 75 #include "myhistedit.h" 76 #endif 77 78 79 /* flags in argument to evaltree */ 80 #define EV_EXIT 01 /* exit after evaluating tree */ 81 #define EV_TESTED 02 /* exit status is checked; ignore -e flag */ 82 #define EV_BACKCMD 04 /* command executing within back quotes */ 83 84 int evalskip; /* set if we are skipping commands */ 85 STATIC int skipcount; /* number of levels to skip */ 86 MKINIT int loopnest; /* current loop nesting level */ 87 int funcnest; /* depth of function calls */ 88 89 90 char *commandname; 91 struct strlist *cmdenviron; 92 int exitstatus; /* exit status of last command */ 93 int oexitstatus; /* saved exit status */ 94 95 96 STATIC void evalloop __P((union node *, int)); 97 STATIC void evalfor __P((union node *, int)); 98 STATIC void evalcase __P((union node *, int)); 99 STATIC void evalsubshell __P((union node *, int)); 100 STATIC void expredir __P((union node *)); 101 STATIC void evalpipe __P((union node *)); 102 STATIC void evalcommand __P((union node *, int, struct backcmd *)); 103 STATIC void prehash __P((union node *)); 104 105 106 /* 107 * Called to reset things after an exception. 108 */ 109 110 #ifdef mkinit 111 INCLUDE "eval.h" 112 113 RESET { 114 evalskip = 0; 115 loopnest = 0; 116 funcnest = 0; 117 } 118 119 SHELLPROC { 120 exitstatus = 0; 121 } 122 #endif 123 124 125 126 /* 127 * The eval commmand. 128 */ 129 130 int 131 evalcmd(argc, argv) 132 int argc; 133 char **argv; 134 { 135 char *p; 136 char *concat; 137 char **ap; 138 139 if (argc > 1) { 140 p = argv[1]; 141 if (argc > 2) { 142 STARTSTACKSTR(concat); 143 ap = argv + 2; 144 for (;;) { 145 while (*p) 146 STPUTC(*p++, concat); 147 if ((p = *ap++) == NULL) 148 break; 149 STPUTC(' ', concat); 150 } 151 STPUTC('\0', concat); 152 p = grabstackstr(concat); 153 } 154 evalstring(p, EV_TESTED); 155 } 156 return exitstatus; 157 } 158 159 160 /* 161 * Execute a command or commands contained in a string. 162 */ 163 164 void 165 evalstring(s, flag) 166 char *s; 167 int flag; 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, flag); 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 SMALL 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, flags & EV_TESTED); 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 /* don't bomb out on "set -e; false && true" */ 214 flags |= EV_TESTED; 215 goto out; 216 } 217 evaltree(n->nbinary.ch2, flags | EV_TESTED); 218 break; 219 case NOR: 220 evaltree(n->nbinary.ch1, EV_TESTED); 221 if (evalskip || exitstatus == 0) 222 goto out; 223 evaltree(n->nbinary.ch2, flags | EV_TESTED); 224 break; 225 case NREDIR: 226 expredir(n->nredir.redirect); 227 redirect(n->nredir.redirect, REDIR_PUSH); 228 evaltree(n->nredir.n, flags); 229 popredir(); 230 break; 231 case NSUBSHELL: 232 evalsubshell(n, flags); 233 break; 234 case NBACKGND: 235 evalsubshell(n, flags); 236 break; 237 case NIF: { 238 evaltree(n->nif.test, EV_TESTED); 239 if (evalskip) 240 goto out; 241 if (exitstatus == 0) 242 evaltree(n->nif.ifpart, flags); 243 else if (n->nif.elsepart) 244 evaltree(n->nif.elsepart, flags); 245 else 246 exitstatus = 0; 247 break; 248 } 249 case NWHILE: 250 case NUNTIL: 251 evalloop(n, flags); 252 break; 253 case NFOR: 254 evalfor(n, flags); 255 break; 256 case NCASE: 257 evalcase(n, flags); 258 break; 259 case NDEFUN: 260 defun(n->narg.text, n->narg.next); 261 exitstatus = 0; 262 break; 263 case NNOT: 264 evaltree(n->nnot.com, EV_TESTED); 265 exitstatus = !exitstatus; 266 break; 267 268 case NPIPE: 269 evalpipe(n); 270 break; 271 case NCMD: 272 evalcommand(n, flags, (struct backcmd *)NULL); 273 break; 274 default: 275 out1fmt("Node type = %d\n", n->type); 276 flushout(&output); 277 break; 278 } 279 out: 280 if (pendingsigs) 281 dotrap(); 282 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 283 exitshell(exitstatus); 284 } 285 286 287 STATIC void 288 evalloop(n, flags) 289 union node *n; 290 int flags; 291 { 292 int status; 293 294 loopnest++; 295 status = 0; 296 for (;;) { 297 evaltree(n->nbinary.ch1, EV_TESTED); 298 if (evalskip) { 299 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 300 evalskip = 0; 301 continue; 302 } 303 if (evalskip == SKIPBREAK && --skipcount <= 0) 304 evalskip = 0; 305 break; 306 } 307 if (n->type == NWHILE) { 308 if (exitstatus != 0) 309 break; 310 } else { 311 if (exitstatus == 0) 312 break; 313 } 314 evaltree(n->nbinary.ch2, flags & EV_TESTED); 315 status = exitstatus; 316 if (evalskip) 317 goto skipping; 318 } 319 loopnest--; 320 exitstatus = status; 321 } 322 323 324 325 STATIC void 326 evalfor(n, flags) 327 union node *n; 328 int flags; 329 { 330 struct arglist arglist; 331 union node *argp; 332 struct strlist *sp; 333 struct stackmark smark; 334 335 setstackmark(&smark); 336 arglist.lastp = &arglist.list; 337 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 338 oexitstatus = exitstatus; 339 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE | EXP_RECORD); 340 if (evalskip) 341 goto out; 342 } 343 *arglist.lastp = NULL; 344 345 exitstatus = 0; 346 loopnest++; 347 for (sp = arglist.list ; sp ; sp = sp->next) { 348 setvar(n->nfor.var, sp->text, 0); 349 evaltree(n->nfor.body, flags & EV_TESTED); 350 if (evalskip) { 351 if (evalskip == SKIPCONT && --skipcount <= 0) { 352 evalskip = 0; 353 continue; 354 } 355 if (evalskip == SKIPBREAK && --skipcount <= 0) 356 evalskip = 0; 357 break; 358 } 359 } 360 loopnest--; 361 out: 362 popstackmark(&smark); 363 } 364 365 366 367 STATIC void 368 evalcase(n, flags) 369 union node *n; 370 int flags; 371 { 372 union node *cp; 373 union node *patp; 374 struct arglist arglist; 375 struct stackmark smark; 376 377 setstackmark(&smark); 378 arglist.lastp = &arglist.list; 379 oexitstatus = exitstatus; 380 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 381 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 382 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 383 if (casematch(patp, arglist.list->text)) { 384 if (evalskip == 0) { 385 evaltree(cp->nclist.body, flags); 386 } 387 goto out; 388 } 389 } 390 } 391 out: 392 popstackmark(&smark); 393 } 394 395 396 397 /* 398 * Kick off a subshell to evaluate a tree. 399 */ 400 401 STATIC void 402 evalsubshell(n, flags) 403 union node *n; 404 int flags; 405 { 406 struct job *jp; 407 int backgnd = (n->type == NBACKGND); 408 409 expredir(n->nredir.redirect); 410 jp = makejob(n, 1); 411 if (forkshell(jp, n, backgnd) == 0) { 412 if (backgnd) 413 flags &=~ EV_TESTED; 414 redirect(n->nredir.redirect, 0); 415 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 416 } 417 if (! backgnd) { 418 INTOFF; 419 exitstatus = waitforjob(jp); 420 INTON; 421 } 422 } 423 424 425 426 /* 427 * Compute the names of the files in a redirection list. 428 */ 429 430 STATIC void 431 expredir(n) 432 union node *n; 433 { 434 union node *redir; 435 436 for (redir = n ; redir ; redir = redir->nfile.next) { 437 struct arglist fn; 438 fn.lastp = &fn.list; 439 oexitstatus = exitstatus; 440 switch (redir->type) { 441 case NFROMTO: 442 case NFROM: 443 case NTO: 444 case NAPPEND: 445 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 446 redir->nfile.expfname = fn.list->text; 447 break; 448 case NFROMFD: 449 case NTOFD: 450 if (redir->ndup.vname) { 451 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 452 fixredir(redir, fn.list->text, 1); 453 } 454 break; 455 } 456 } 457 } 458 459 460 461 /* 462 * Evaluate a pipeline. All the processes in the pipeline are children 463 * of the process creating the pipeline. (This differs from some versions 464 * of the shell, which make the last process in a pipeline the parent 465 * of all the rest.) 466 */ 467 468 STATIC void 469 evalpipe(n) 470 union node *n; 471 { 472 struct job *jp; 473 struct nodelist *lp; 474 int pipelen; 475 int prevfd; 476 int pip[2]; 477 478 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 479 pipelen = 0; 480 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 481 pipelen++; 482 INTOFF; 483 jp = makejob(n, pipelen); 484 prevfd = -1; 485 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 486 prehash(lp->n); 487 pip[1] = -1; 488 if (lp->next) { 489 if (pipe(pip) < 0) { 490 close(prevfd); 491 error("Pipe call failed"); 492 } 493 } 494 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 495 INTON; 496 if (prevfd > 0) { 497 close(0); 498 copyfd(prevfd, 0); 499 close(prevfd); 500 } 501 if (pip[1] >= 0) { 502 close(pip[0]); 503 if (pip[1] != 1) { 504 close(1); 505 copyfd(pip[1], 1); 506 close(pip[1]); 507 } 508 } 509 evaltree(lp->n, EV_EXIT); 510 } 511 if (prevfd >= 0) 512 close(prevfd); 513 prevfd = pip[0]; 514 close(pip[1]); 515 } 516 INTON; 517 if (n->npipe.backgnd == 0) { 518 INTOFF; 519 exitstatus = waitforjob(jp); 520 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 521 INTON; 522 } 523 } 524 525 526 527 /* 528 * Execute a command inside back quotes. If it's a builtin command, we 529 * want to save its output in a block obtained from malloc. Otherwise 530 * we fork off a subprocess and get the output of the command via a pipe. 531 * Should be called with interrupts off. 532 */ 533 534 void 535 evalbackcmd(n, result) 536 union node *n; 537 struct backcmd *result; 538 { 539 int pip[2]; 540 struct job *jp; 541 struct stackmark smark; /* unnecessary */ 542 543 setstackmark(&smark); 544 result->fd = -1; 545 result->buf = NULL; 546 result->nleft = 0; 547 result->jp = NULL; 548 if (n == NULL) { 549 exitstatus = 0; 550 goto out; 551 } 552 #ifdef notyet 553 /* 554 * For now we disable executing builtins in the same 555 * context as the shell, because we are not keeping 556 * enough state to recover from changes that are 557 * supposed only to affect subshells. eg. echo "`cd /`" 558 */ 559 if (n->type == NCMD) { 560 exitstatus = oexitstatus; 561 evalcommand(n, EV_BACKCMD, result); 562 } else 563 #endif 564 { 565 exitstatus = 0; 566 if (pipe(pip) < 0) 567 error("Pipe call failed"); 568 jp = makejob(n, 1); 569 if (forkshell(jp, n, FORK_NOJOB) == 0) { 570 FORCEINTON; 571 close(pip[0]); 572 if (pip[1] != 1) { 573 close(1); 574 copyfd(pip[1], 1); 575 close(pip[1]); 576 } 577 eflag = 0; 578 evaltree(n, EV_EXIT); 579 } 580 close(pip[1]); 581 result->fd = pip[0]; 582 result->jp = jp; 583 } 584 out: 585 popstackmark(&smark); 586 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 587 result->fd, result->buf, result->nleft, result->jp)); 588 } 589 590 591 592 /* 593 * Execute a simple command. 594 */ 595 596 STATIC void 597 evalcommand(cmd, flags, backcmd) 598 union node *cmd; 599 int flags; 600 struct backcmd *backcmd; 601 { 602 struct stackmark smark; 603 union node *argp; 604 struct arglist arglist; 605 struct arglist varlist; 606 char **argv; 607 int argc; 608 char **envp; 609 int varflag; 610 struct strlist *sp; 611 int mode; 612 int pip[2]; 613 struct cmdentry cmdentry; 614 struct job *jp; 615 struct jmploc jmploc; 616 struct jmploc *volatile savehandler; 617 char *volatile savecmdname; 618 volatile struct shparam saveparam; 619 struct localvar *volatile savelocalvars; 620 volatile int e; 621 char *lastarg; 622 #if __GNUC__ 623 /* Avoid longjmp clobbering */ 624 (void) &argv; 625 (void) &argc; 626 (void) &lastarg; 627 (void) &flags; 628 #endif 629 630 /* First expand the arguments. */ 631 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 632 setstackmark(&smark); 633 arglist.lastp = &arglist.list; 634 varlist.lastp = &varlist.list; 635 varflag = 1; 636 oexitstatus = exitstatus; 637 exitstatus = 0; 638 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 639 char *p = argp->narg.text; 640 if (varflag && is_name(*p)) { 641 do { 642 p++; 643 } while (is_in_name(*p)); 644 if (*p == '=') { 645 expandarg(argp, &varlist, EXP_VARTILDE); 646 continue; 647 } 648 } 649 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 650 varflag = 0; 651 } 652 *arglist.lastp = NULL; 653 *varlist.lastp = NULL; 654 expredir(cmd->ncmd.redirect); 655 argc = 0; 656 for (sp = arglist.list ; sp ; sp = sp->next) 657 argc++; 658 argv = stalloc(sizeof (char *) * (argc + 1)); 659 660 for (sp = arglist.list ; sp ; sp = sp->next) { 661 TRACE(("evalcommand arg: %s\n", sp->text)); 662 *argv++ = sp->text; 663 } 664 *argv = NULL; 665 lastarg = NULL; 666 if (iflag && funcnest == 0 && argc > 0) 667 lastarg = argv[-1]; 668 argv -= argc; 669 670 /* Print the command if xflag is set. */ 671 if (xflag) { 672 outc('+', &errout); 673 for (sp = varlist.list ; sp ; sp = sp->next) { 674 outc(' ', &errout); 675 out2str(sp->text); 676 } 677 for (sp = arglist.list ; sp ; sp = sp->next) { 678 outc(' ', &errout); 679 out2str(sp->text); 680 } 681 outc('\n', &errout); 682 flushout(&errout); 683 } 684 685 /* Now locate the command. */ 686 if (argc == 0) { 687 cmdentry.cmdtype = CMDBUILTIN; 688 cmdentry.u.index = BLTINCMD; 689 } else { 690 static const char PATH[] = "PATH="; 691 const char *path = pathval(); 692 693 /* 694 * Modify the command lookup path, if a PATH= assignment 695 * is present 696 */ 697 for (sp = varlist.list ; sp ; sp = sp->next) 698 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) 699 path = sp->text + sizeof(PATH) - 1; 700 701 find_command(argv[0], &cmdentry, DO_ERR, path); 702 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 703 exitstatus = 127; 704 flushout(&errout); 705 return; 706 } 707 /* implement the bltin builtin here */ 708 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 709 for (;;) { 710 argv++; 711 if (--argc == 0) 712 break; 713 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 714 outfmt(&errout, "%s: not found\n", *argv); 715 exitstatus = 127; 716 flushout(&errout); 717 return; 718 } 719 if (cmdentry.u.index != BLTINCMD) 720 break; 721 } 722 } 723 } 724 725 /* Fork off a child process if necessary. */ 726 if (cmd->ncmd.backgnd 727 || (cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0) 728 || ((flags & EV_BACKCMD) != 0 729 && (cmdentry.cmdtype != CMDBUILTIN 730 || cmdentry.u.index == DOTCMD 731 || cmdentry.u.index == EVALCMD))) { 732 jp = makejob(cmd, 1); 733 mode = cmd->ncmd.backgnd; 734 if (flags & EV_BACKCMD) { 735 mode = FORK_NOJOB; 736 if (pipe(pip) < 0) 737 error("Pipe call failed"); 738 } 739 if (forkshell(jp, cmd, mode) != 0) 740 goto parent; /* at end of routine */ 741 if (flags & EV_BACKCMD) { 742 FORCEINTON; 743 close(pip[0]); 744 if (pip[1] != 1) { 745 close(1); 746 copyfd(pip[1], 1); 747 close(pip[1]); 748 } 749 } 750 flags |= EV_EXIT; 751 } 752 753 /* This is the child process if a fork occurred. */ 754 /* Execute the command. */ 755 if (cmdentry.cmdtype == CMDFUNCTION) { 756 #ifdef DEBUG 757 trputs("Shell function: "); trargs(argv); 758 #endif 759 redirect(cmd->ncmd.redirect, REDIR_PUSH); 760 saveparam = shellparam; 761 shellparam.malloc = 0; 762 shellparam.reset = 1; 763 shellparam.nparam = argc - 1; 764 shellparam.p = argv + 1; 765 shellparam.optnext = NULL; 766 INTOFF; 767 savelocalvars = localvars; 768 localvars = NULL; 769 INTON; 770 if (setjmp(jmploc.loc)) { 771 if (exception == EXSHELLPROC) { 772 freeparam((volatile struct shparam *) 773 &saveparam); 774 } else { 775 freeparam(&shellparam); 776 shellparam = saveparam; 777 } 778 poplocalvars(); 779 localvars = savelocalvars; 780 handler = savehandler; 781 longjmp(handler->loc, 1); 782 } 783 savehandler = handler; 784 handler = &jmploc; 785 for (sp = varlist.list ; sp ; sp = sp->next) 786 mklocal(sp->text); 787 funcnest++; 788 evaltree(cmdentry.u.func, flags & EV_TESTED); 789 funcnest--; 790 INTOFF; 791 poplocalvars(); 792 localvars = savelocalvars; 793 freeparam(&shellparam); 794 shellparam = saveparam; 795 handler = savehandler; 796 popredir(); 797 INTON; 798 if (evalskip == SKIPFUNC) { 799 evalskip = 0; 800 skipcount = 0; 801 } 802 if (flags & EV_EXIT) 803 exitshell(exitstatus); 804 } else if (cmdentry.cmdtype == CMDBUILTIN) { 805 #ifdef DEBUG 806 trputs("builtin command: "); trargs(argv); 807 #endif 808 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 809 if (flags == EV_BACKCMD) { 810 memout.nleft = 0; 811 memout.nextc = memout.buf; 812 memout.bufsize = 64; 813 mode |= REDIR_BACKQ; 814 } 815 redirect(cmd->ncmd.redirect, mode); 816 savecmdname = commandname; 817 cmdenviron = varlist.list; 818 e = -1; 819 if (setjmp(jmploc.loc)) { 820 e = exception; 821 exitstatus = (e == EXINT)? SIGINT+128 : 2; 822 goto cmddone; 823 } 824 savehandler = handler; 825 handler = &jmploc; 826 commandname = argv[0]; 827 argptr = argv + 1; 828 optptr = NULL; /* initialize nextopt */ 829 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 830 flushall(); 831 cmddone: 832 out1 = &output; 833 out2 = &errout; 834 freestdout(); 835 cmdenviron = NULL; 836 if (e != EXSHELLPROC) { 837 commandname = savecmdname; 838 if (flags & EV_EXIT) 839 exitshell(exitstatus); 840 } 841 handler = savehandler; 842 if (e != -1) { 843 if ((e != EXERROR && e != EXEXEC) 844 || cmdentry.u.index == BLTINCMD 845 || cmdentry.u.index == DOTCMD 846 || cmdentry.u.index == EVALCMD 847 #ifndef SMALL 848 || cmdentry.u.index == HISTCMD 849 #endif 850 || cmdentry.u.index == EXECCMD) 851 exraise(e); 852 FORCEINTON; 853 } 854 if (cmdentry.u.index != EXECCMD) 855 popredir(); 856 if (flags == EV_BACKCMD) { 857 backcmd->buf = memout.buf; 858 backcmd->nleft = memout.nextc - memout.buf; 859 memout.buf = NULL; 860 } 861 } else { 862 #ifdef DEBUG 863 trputs("normal command: "); trargs(argv); 864 #endif 865 clearredir(); 866 redirect(cmd->ncmd.redirect, 0); 867 for (sp = varlist.list ; sp ; sp = sp->next) 868 setvareq(sp->text, VEXPORT|VSTACK); 869 envp = environment(); 870 shellexec(argv, envp, pathval(), cmdentry.u.index); 871 } 872 goto out; 873 874 parent: /* parent process gets here (if we forked) */ 875 if (mode == 0) { /* argument to fork */ 876 INTOFF; 877 exitstatus = waitforjob(jp); 878 INTON; 879 } else if (mode == 2) { 880 backcmd->fd = pip[0]; 881 close(pip[1]); 882 backcmd->jp = jp; 883 } 884 885 out: 886 if (lastarg) 887 setvar("_", lastarg, 0); 888 popstackmark(&smark); 889 890 if (eflag && exitstatus && !(flags & EV_TESTED)) 891 exitshell(exitstatus); 892 } 893 894 895 896 /* 897 * Search for a command. This is called before we fork so that the 898 * location of the command will be available in the parent as well as 899 * the child. The check for "goodname" is an overly conservative 900 * check that the name will not be subject to expansion. 901 */ 902 903 STATIC void 904 prehash(n) 905 union node *n; 906 { 907 struct cmdentry entry; 908 909 if (n->type == NCMD && n->ncmd.args) 910 if (goodname(n->ncmd.args->narg.text)) 911 find_command(n->ncmd.args->narg.text, &entry, 0, 912 pathval()); 913 } 914 915 916 917 /* 918 * Builtin commands. Builtin commands whose functions are closely 919 * tied to evaluation are implemented here. 920 */ 921 922 /* 923 * No command given, or a bltin command with no arguments. Set the 924 * specified variables. 925 */ 926 927 int 928 bltincmd(argc, argv) 929 int argc; 930 char **argv; 931 { 932 listsetvar(cmdenviron); 933 /* 934 * Preserve exitstatus of a previous possible redirection 935 * as POSIX mandates 936 */ 937 return exitstatus; 938 } 939 940 941 /* 942 * Handle break and continue commands. Break, continue, and return are 943 * all handled by setting the evalskip flag. The evaluation routines 944 * above all check this flag, and if it is set they start skipping 945 * commands rather than executing them. The variable skipcount is 946 * the number of loops to break/continue, or the number of function 947 * levels to return. (The latter is always 1.) It should probably 948 * be an error to break out of more loops than exist, but it isn't 949 * in the standard shell so we don't make it one here. 950 */ 951 952 int 953 breakcmd(argc, argv) 954 int argc; 955 char **argv; 956 { 957 int n = argc > 1 ? number(argv[1]) : 1; 958 959 if (n > loopnest) 960 n = loopnest; 961 if (n > 0) { 962 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 963 skipcount = n; 964 } 965 return 0; 966 } 967 968 969 /* 970 * The return command. 971 */ 972 973 int 974 returncmd(argc, argv) 975 int argc; 976 char **argv; 977 { 978 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 979 980 if (funcnest) { 981 evalskip = SKIPFUNC; 982 skipcount = 1; 983 return ret; 984 } 985 else { 986 /* Do what ksh does; skip the rest of the file */ 987 evalskip = SKIPFILE; 988 skipcount = 1; 989 return ret; 990 } 991 } 992 993 994 int 995 falsecmd(argc, argv) 996 int argc; 997 char **argv; 998 { 999 return 1; 1000 } 1001 1002 1003 int 1004 truecmd(argc, argv) 1005 int argc; 1006 char **argv; 1007 { 1008 return 0; 1009 } 1010 1011 1012 int 1013 execcmd(argc, argv) 1014 int argc; 1015 char **argv; 1016 { 1017 if (argc > 1) { 1018 struct strlist *sp; 1019 1020 iflag = 0; /* exit on error */ 1021 mflag = 0; 1022 optschanged(); 1023 for (sp = cmdenviron; sp ; sp = sp->next) 1024 setvareq(sp->text, VEXPORT|VSTACK); 1025 shellexec(argv + 1, environment(), pathval(), 0); 1026 } 1027 return 0; 1028 } 1029