1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 40 #endif 41 static const char rcsid[] = 42 "$FreeBSD$"; 43 #endif /* not lint */ 44 45 #include <signal.h> 46 #include <unistd.h> 47 #include <sys/wait.h> /* For WIFSIGNALED(status) */ 48 #include <errno.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 command. 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 flags |= EV_TESTED; 212 goto out; 213 } 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 evaltree(n->nif.test, EV_TESTED); 236 if (evalskip) 237 goto out; 238 if (exitstatus == 0) 239 evaltree(n->nif.ifpart, flags); 240 else if (n->nif.elsepart) 241 evaltree(n->nif.elsepart, flags); 242 else 243 exitstatus = 0; 244 break; 245 } 246 case NWHILE: 247 case NUNTIL: 248 evalloop(n); 249 break; 250 case NFOR: 251 evalfor(n); 252 break; 253 case NCASE: 254 evalcase(n, flags); 255 break; 256 case NDEFUN: 257 defun(n->narg.text, n->narg.next); 258 exitstatus = 0; 259 break; 260 case NNOT: 261 evaltree(n->nnot.com, EV_TESTED); 262 exitstatus = !exitstatus; 263 break; 264 265 case NPIPE: 266 evalpipe(n); 267 break; 268 case NCMD: 269 evalcommand(n, flags, (struct backcmd *)NULL); 270 break; 271 default: 272 out1fmt("Node type = %d\n", n->type); 273 flushout(&output); 274 break; 275 } 276 out: 277 if (pendingsigs) 278 dotrap(); 279 /* 280 * XXX - Like "!(n->type == NSEMI)", more types will probably 281 * need to be excluded from this test. It's probably better 282 * to set or unset EV_TESTED in the loop above than to bloat 283 * the conditional here. 284 */ 285 if ((flags & EV_EXIT) || (eflag && exitstatus 286 && !(flags & EV_TESTED) && !(n->type == NSEMI))) 287 exitshell(exitstatus); 288 } 289 290 291 STATIC void 292 evalloop(n) 293 union node *n; 294 { 295 int status; 296 297 loopnest++; 298 status = 0; 299 for (;;) { 300 evaltree(n->nbinary.ch1, EV_TESTED); 301 if (evalskip) { 302 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 303 evalskip = 0; 304 continue; 305 } 306 if (evalskip == SKIPBREAK && --skipcount <= 0) 307 evalskip = 0; 308 break; 309 } 310 if (n->type == NWHILE) { 311 if (exitstatus != 0) 312 break; 313 } else { 314 if (exitstatus == 0) 315 break; 316 } 317 evaltree(n->nbinary.ch2, 0); 318 status = exitstatus; 319 if (evalskip) 320 goto skipping; 321 } 322 loopnest--; 323 exitstatus = status; 324 } 325 326 327 328 STATIC void 329 evalfor(n) 330 union node *n; 331 { 332 struct arglist arglist; 333 union node *argp; 334 struct strlist *sp; 335 struct stackmark smark; 336 337 setstackmark(&smark); 338 arglist.lastp = &arglist.list; 339 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 340 oexitstatus = exitstatus; 341 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 342 if (evalskip) 343 goto out; 344 } 345 *arglist.lastp = NULL; 346 347 exitstatus = 0; 348 loopnest++; 349 for (sp = arglist.list ; sp ; sp = sp->next) { 350 setvar(n->nfor.var, sp->text, 0); 351 evaltree(n->nfor.body, 0); 352 if (evalskip) { 353 if (evalskip == SKIPCONT && --skipcount <= 0) { 354 evalskip = 0; 355 continue; 356 } 357 if (evalskip == SKIPBREAK && --skipcount <= 0) 358 evalskip = 0; 359 break; 360 } 361 } 362 loopnest--; 363 out: 364 popstackmark(&smark); 365 } 366 367 368 369 STATIC void 370 evalcase(n, flags) 371 union node *n; 372 int flags; 373 { 374 union node *cp; 375 union node *patp; 376 struct arglist arglist; 377 struct stackmark smark; 378 379 setstackmark(&smark); 380 arglist.lastp = &arglist.list; 381 oexitstatus = exitstatus; 382 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 383 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 384 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 385 if (casematch(patp, arglist.list->text)) { 386 if (evalskip == 0) { 387 evaltree(cp->nclist.body, flags); 388 } 389 goto out; 390 } 391 } 392 } 393 out: 394 popstackmark(&smark); 395 } 396 397 398 399 /* 400 * Kick off a subshell to evaluate a tree. 401 */ 402 403 STATIC void 404 evalsubshell(n, flags) 405 union node *n; 406 int flags; 407 { 408 struct job *jp; 409 int backgnd = (n->type == NBACKGND); 410 411 expredir(n->nredir.redirect); 412 jp = makejob(n, 1); 413 if (forkshell(jp, n, backgnd) == 0) { 414 if (backgnd) 415 flags &=~ EV_TESTED; 416 redirect(n->nredir.redirect, 0); 417 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 418 } 419 if (! backgnd) { 420 INTOFF; 421 exitstatus = waitforjob(jp, (int *)NULL); 422 INTON; 423 } 424 } 425 426 427 428 /* 429 * Compute the names of the files in a redirection list. 430 */ 431 432 STATIC void 433 expredir(n) 434 union node *n; 435 { 436 union node *redir; 437 438 for (redir = n ; redir ; redir = redir->nfile.next) { 439 struct arglist fn; 440 fn.lastp = &fn.list; 441 oexitstatus = exitstatus; 442 switch (redir->type) { 443 case NFROM: 444 case NTO: 445 case NFROMTO: 446 case NAPPEND: 447 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 448 redir->nfile.expfname = fn.list->text; 449 break; 450 case NFROMFD: 451 case NTOFD: 452 if (redir->ndup.vname) { 453 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 454 fixredir(redir, fn.list->text, 1); 455 } 456 break; 457 } 458 } 459 } 460 461 462 463 /* 464 * Evaluate a pipeline. All the processes in the pipeline are children 465 * of the process creating the pipeline. (This differs from some versions 466 * of the shell, which make the last process in a pipeline the parent 467 * of all the rest.) 468 */ 469 470 STATIC void 471 evalpipe(n) 472 union node *n; 473 { 474 struct job *jp; 475 struct nodelist *lp; 476 int pipelen; 477 int prevfd; 478 int pip[2]; 479 480 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 481 pipelen = 0; 482 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 483 pipelen++; 484 INTOFF; 485 jp = makejob(n, pipelen); 486 prevfd = -1; 487 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 488 prehash(lp->n); 489 pip[1] = -1; 490 if (lp->next) { 491 if (pipe(pip) < 0) { 492 close(prevfd); 493 error("Pipe call failed: %s", strerror(errno)); 494 } 495 } 496 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 497 INTON; 498 if (prevfd > 0) { 499 close(0); 500 copyfd(prevfd, 0); 501 close(prevfd); 502 } 503 if (pip[1] >= 0) { 504 if (!(prevfd >= 0 && pip[0] == 0)) 505 close(pip[0]); 506 if (pip[1] != 1) { 507 close(1); 508 copyfd(pip[1], 1); 509 close(pip[1]); 510 } 511 } 512 evaltree(lp->n, EV_EXIT); 513 } 514 if (prevfd >= 0) 515 close(prevfd); 516 prevfd = pip[0]; 517 close(pip[1]); 518 } 519 INTON; 520 if (n->npipe.backgnd == 0) { 521 INTOFF; 522 exitstatus = waitforjob(jp, (int *)NULL); 523 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 524 INTON; 525 } 526 } 527 528 529 530 /* 531 * Execute a command inside back quotes. If it's a builtin command, we 532 * want to save its output in a block obtained from malloc. Otherwise 533 * we fork off a subprocess and get the output of the command via a pipe. 534 * Should be called with interrupts off. 535 */ 536 537 void 538 evalbackcmd(n, result) 539 union node *n; 540 struct backcmd *result; 541 { 542 int pip[2]; 543 struct job *jp; 544 struct stackmark smark; /* unnecessary */ 545 546 setstackmark(&smark); 547 result->fd = -1; 548 result->buf = NULL; 549 result->nleft = 0; 550 result->jp = NULL; 551 if (n == NULL) { 552 exitstatus = 0; 553 goto out; 554 } 555 if (n->type == NCMD) { 556 exitstatus = oexitstatus; 557 evalcommand(n, EV_BACKCMD, result); 558 } else { 559 exitstatus = 0; 560 if (pipe(pip) < 0) 561 error("Pipe call failed: %s", strerror(errno)); 562 jp = makejob(n, 1); 563 if (forkshell(jp, n, FORK_NOJOB) == 0) { 564 FORCEINTON; 565 close(pip[0]); 566 if (pip[1] != 1) { 567 close(1); 568 copyfd(pip[1], 1); 569 close(pip[1]); 570 } 571 evaltree(n, EV_EXIT); 572 } 573 close(pip[1]); 574 result->fd = pip[0]; 575 result->jp = jp; 576 } 577 out: 578 popstackmark(&smark); 579 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 580 result->fd, result->buf, result->nleft, result->jp)); 581 } 582 583 584 585 /* 586 * Execute a simple command. 587 */ 588 589 STATIC void 590 evalcommand(cmd, flags, backcmd) 591 union node *cmd; 592 int flags; 593 struct backcmd *backcmd; 594 { 595 struct stackmark smark; 596 union node *argp; 597 struct arglist arglist; 598 struct arglist varlist; 599 char **argv; 600 int argc; 601 char **envp; 602 int varflag; 603 struct strlist *sp; 604 int mode; 605 int pip[2]; 606 struct cmdentry cmdentry; 607 struct job *jp; 608 struct jmploc jmploc; 609 struct jmploc *volatile savehandler; 610 char *volatile savecmdname; 611 volatile struct shparam saveparam; 612 struct localvar *volatile savelocalvars; 613 volatile int e; 614 char *lastarg; 615 int realstatus; 616 int do_clearcmdentry; 617 #if __GNUC__ 618 /* Avoid longjmp clobbering */ 619 (void) &argv; 620 (void) &argc; 621 (void) &lastarg; 622 (void) &flags; 623 (void) &do_clearcmdentry; 624 #endif 625 626 /* First expand the arguments. */ 627 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 628 setstackmark(&smark); 629 arglist.lastp = &arglist.list; 630 varlist.lastp = &varlist.list; 631 varflag = 1; 632 do_clearcmdentry = 0; 633 oexitstatus = exitstatus; 634 exitstatus = 0; 635 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 636 char *p = argp->narg.text; 637 if (varflag && is_name(*p)) { 638 do { 639 p++; 640 } while (is_in_name(*p)); 641 if (*p == '=') { 642 expandarg(argp, &varlist, EXP_VARTILDE); 643 continue; 644 } 645 } 646 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 647 varflag = 0; 648 } 649 *arglist.lastp = NULL; 650 *varlist.lastp = NULL; 651 expredir(cmd->ncmd.redirect); 652 argc = 0; 653 for (sp = arglist.list ; sp ; sp = sp->next) 654 argc++; 655 argv = stalloc(sizeof (char *) * (argc + 1)); 656 657 for (sp = arglist.list ; sp ; sp = sp->next) { 658 TRACE(("evalcommand arg: %s\n", sp->text)); 659 *argv++ = sp->text; 660 } 661 *argv = NULL; 662 lastarg = NULL; 663 if (iflag && funcnest == 0 && argc > 0) 664 lastarg = argv[-1]; 665 argv -= argc; 666 667 /* Print the command if xflag is set. */ 668 if (xflag) { 669 outc('+', &errout); 670 for (sp = varlist.list ; sp ; sp = sp->next) { 671 outc(' ', &errout); 672 out2str(sp->text); 673 } 674 for (sp = arglist.list ; sp ; sp = sp->next) { 675 outc(' ', &errout); 676 out2str(sp->text); 677 } 678 outc('\n', &errout); 679 flushout(&errout); 680 } 681 682 /* Now locate the command. */ 683 if (argc == 0) { 684 cmdentry.cmdtype = CMDBUILTIN; 685 cmdentry.u.index = BLTINCMD; 686 } else { 687 static const char PATH[] = "PATH="; 688 char *path = pathval(); 689 690 /* 691 * Modify the command lookup path, if a PATH= assignment 692 * is present 693 */ 694 for (sp = varlist.list ; sp ; sp = sp->next) 695 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 696 path = sp->text + sizeof(PATH) - 1; 697 /* 698 * On `PATH=... command`, we need to make 699 * sure that the command isn't using the 700 * non-updated hash table of the outer PATH 701 * setting and we need to make sure that 702 * the hash table isn't filled with items 703 * from the temporary setting. 704 * 705 * It would be better to forbit using and 706 * updating the table while this command 707 * runs, by the command finding mechanism 708 * is heavily integrated with hash handling, 709 * so we just delete the hash before and after 710 * the command runs. Partly deleting like 711 * changepatch() does doesn't seem worth the 712 * bookinging effort, since most such runs add 713 * diretories in front of the new PATH. 714 */ 715 clearcmdentry(0); 716 do_clearcmdentry = 1; 717 } 718 719 find_command(argv[0], &cmdentry, 1, path); 720 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 721 exitstatus = 127; 722 flushout(&errout); 723 return; 724 } 725 /* implement the bltin builtin here */ 726 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 727 for (;;) { 728 argv++; 729 if (--argc == 0) 730 break; 731 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 732 outfmt(&errout, "%s: not found\n", *argv); 733 exitstatus = 127; 734 flushout(&errout); 735 return; 736 } 737 if (cmdentry.u.index != BLTINCMD) 738 break; 739 } 740 } 741 } 742 743 /* Fork off a child process if necessary. */ 744 if (cmd->ncmd.backgnd 745 || (cmdentry.cmdtype == CMDNORMAL 746 && ((flags & EV_EXIT) == 0 || Tflag)) 747 || ((flags & EV_BACKCMD) != 0 748 && (cmdentry.cmdtype != CMDBUILTIN 749 || cmdentry.u.index == CDCMD 750 || cmdentry.u.index == DOTCMD 751 || cmdentry.u.index == EVALCMD))) { 752 jp = makejob(cmd, 1); 753 mode = cmd->ncmd.backgnd; 754 if (flags & EV_BACKCMD) { 755 mode = FORK_NOJOB; 756 if (pipe(pip) < 0) 757 error("Pipe call failed: %s", strerror(errno)); 758 } 759 if (forkshell(jp, cmd, mode) != 0) 760 goto parent; /* at end of routine */ 761 if (flags & EV_BACKCMD) { 762 FORCEINTON; 763 close(pip[0]); 764 if (pip[1] != 1) { 765 close(1); 766 copyfd(pip[1], 1); 767 close(pip[1]); 768 } 769 } 770 flags |= EV_EXIT; 771 } 772 773 /* This is the child process if a fork occurred. */ 774 /* Execute the command. */ 775 if (cmdentry.cmdtype == CMDFUNCTION) { 776 #ifdef DEBUG 777 trputs("Shell function: "); trargs(argv); 778 #endif 779 redirect(cmd->ncmd.redirect, REDIR_PUSH); 780 saveparam = shellparam; 781 shellparam.malloc = 0; 782 shellparam.reset = 1; 783 shellparam.nparam = argc - 1; 784 shellparam.p = argv + 1; 785 shellparam.optnext = NULL; 786 INTOFF; 787 savelocalvars = localvars; 788 localvars = NULL; 789 INTON; 790 if (setjmp(jmploc.loc)) { 791 if (exception == EXSHELLPROC) 792 freeparam((struct shparam *)&saveparam); 793 else { 794 freeparam(&shellparam); 795 shellparam = saveparam; 796 } 797 poplocalvars(); 798 localvars = savelocalvars; 799 handler = savehandler; 800 longjmp(handler->loc, 1); 801 } 802 savehandler = handler; 803 handler = &jmploc; 804 for (sp = varlist.list ; sp ; sp = sp->next) 805 mklocal(sp->text); 806 funcnest++; 807 if (flags & EV_TESTED) 808 evaltree(cmdentry.u.func, EV_TESTED); 809 else 810 evaltree(cmdentry.u.func, 0); 811 funcnest--; 812 INTOFF; 813 poplocalvars(); 814 localvars = savelocalvars; 815 freeparam(&shellparam); 816 shellparam = saveparam; 817 handler = savehandler; 818 popredir(); 819 INTON; 820 if (evalskip == SKIPFUNC) { 821 evalskip = 0; 822 skipcount = 0; 823 } 824 if (flags & EV_EXIT) 825 exitshell(exitstatus); 826 } else if (cmdentry.cmdtype == CMDBUILTIN) { 827 #ifdef DEBUG 828 trputs("builtin command: "); trargs(argv); 829 #endif 830 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 831 if (flags == EV_BACKCMD) { 832 memout.nleft = 0; 833 memout.nextc = memout.buf; 834 memout.bufsize = 64; 835 mode |= REDIR_BACKQ; 836 } 837 redirect(cmd->ncmd.redirect, mode); 838 savecmdname = commandname; 839 cmdenviron = varlist.list; 840 e = -1; 841 if (setjmp(jmploc.loc)) { 842 e = exception; 843 exitstatus = (e == EXINT)? SIGINT+128 : 2; 844 goto cmddone; 845 } 846 savehandler = handler; 847 handler = &jmploc; 848 commandname = argv[0]; 849 argptr = argv + 1; 850 optptr = NULL; /* initialize nextopt */ 851 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 852 flushall(); 853 cmddone: 854 cmdenviron = NULL; 855 out1 = &output; 856 out2 = &errout; 857 freestdout(); 858 if (e != EXSHELLPROC) { 859 commandname = savecmdname; 860 if (flags & EV_EXIT) { 861 exitshell(exitstatus); 862 } 863 } 864 handler = savehandler; 865 if (e != -1) { 866 if ((e != EXERROR && e != EXEXEC) 867 || cmdentry.u.index == BLTINCMD 868 || cmdentry.u.index == DOTCMD 869 || cmdentry.u.index == EVALCMD 870 #ifndef NO_HISTORY 871 || cmdentry.u.index == HISTCMD 872 #endif 873 || cmdentry.u.index == EXECCMD) 874 exraise(e); 875 FORCEINTON; 876 } 877 if (cmdentry.u.index != EXECCMD) 878 popredir(); 879 if (flags == EV_BACKCMD) { 880 backcmd->buf = memout.buf; 881 backcmd->nleft = memout.nextc - memout.buf; 882 memout.buf = NULL; 883 } 884 } else { 885 #ifdef DEBUG 886 trputs("normal command: "); trargs(argv); 887 #endif 888 clearredir(); 889 redirect(cmd->ncmd.redirect, 0); 890 for (sp = varlist.list ; sp ; sp = sp->next) 891 setvareq(sp->text, VEXPORT|VSTACK); 892 envp = environment(); 893 shellexec(argv, envp, pathval(), cmdentry.u.index); 894 /*NOTREACHED*/ 895 } 896 goto out; 897 898 parent: /* parent process gets here (if we forked) */ 899 if (mode == 0) { /* argument to fork */ 900 INTOFF; 901 exitstatus = waitforjob(jp, &realstatus); 902 INTON; 903 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 904 evalskip = SKIPBREAK; 905 skipcount = loopnest; 906 } 907 } else if (mode == 2) { 908 backcmd->fd = pip[0]; 909 close(pip[1]); 910 backcmd->jp = jp; 911 } 912 913 out: 914 if (lastarg) 915 setvar("_", lastarg, 0); 916 if (do_clearcmdentry) 917 clearcmdentry(0); 918 popstackmark(&smark); 919 } 920 921 922 923 /* 924 * Search for a command. This is called before we fork so that the 925 * location of the command will be available in the parent as well as 926 * the child. The check for "goodname" is an overly conservative 927 * check that the name will not be subject to expansion. 928 */ 929 930 STATIC void 931 prehash(n) 932 union node *n; 933 { 934 struct cmdentry entry; 935 936 if (n->type == NCMD && n->ncmd.args) 937 if (goodname(n->ncmd.args->narg.text)) 938 find_command(n->ncmd.args->narg.text, &entry, 0, 939 pathval()); 940 } 941 942 943 944 /* 945 * Builtin commands. Builtin commands whose functions are closely 946 * tied to evaluation are implemented here. 947 */ 948 949 /* 950 * No command given, or a bltin command with no arguments. Set the 951 * specified variables. 952 */ 953 954 int 955 bltincmd(argc, argv) 956 int argc __unused; 957 char **argv __unused; 958 { 959 listsetvar(cmdenviron); 960 /* 961 * Preserve exitstatus of a previous possible redirection 962 * as POSIX mandates 963 */ 964 return exitstatus; 965 } 966 967 968 /* 969 * Handle break and continue commands. Break, continue, and return are 970 * all handled by setting the evalskip flag. The evaluation routines 971 * above all check this flag, and if it is set they start skipping 972 * commands rather than executing them. The variable skipcount is 973 * the number of loops to break/continue, or the number of function 974 * levels to return. (The latter is always 1.) It should probably 975 * be an error to break out of more loops than exist, but it isn't 976 * in the standard shell so we don't make it one here. 977 */ 978 979 int 980 breakcmd(argc, argv) 981 int argc; 982 char **argv; 983 { 984 int n = argc > 1 ? number(argv[1]) : 1; 985 986 if (n > loopnest) 987 n = loopnest; 988 if (n > 0) { 989 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 990 skipcount = n; 991 } 992 return 0; 993 } 994 995 996 /* 997 * The return command. 998 */ 999 1000 int 1001 returncmd(argc, argv) 1002 int argc; 1003 char **argv; 1004 { 1005 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1006 1007 if (funcnest) { 1008 evalskip = SKIPFUNC; 1009 skipcount = 1; 1010 } else { 1011 /* skip the rest of the file */ 1012 evalskip = SKIPFILE; 1013 skipcount = 1; 1014 } 1015 return ret; 1016 } 1017 1018 1019 int 1020 falsecmd(argc, argv) 1021 int argc __unused; 1022 char **argv __unused; 1023 { 1024 return 1; 1025 } 1026 1027 1028 int 1029 truecmd(argc, argv) 1030 int argc __unused; 1031 char **argv __unused; 1032 { 1033 return 0; 1034 } 1035 1036 1037 int 1038 execcmd(argc, argv) 1039 int argc; 1040 char **argv; 1041 { 1042 if (argc > 1) { 1043 struct strlist *sp; 1044 1045 iflag = 0; /* exit on error */ 1046 mflag = 0; 1047 optschanged(); 1048 for (sp = cmdenviron; sp ; sp = sp->next) 1049 setvareq(sp->text, VEXPORT|VSTACK); 1050 shellexec(argv + 1, environment(), pathval(), 0); 1051 1052 } 1053 return 0; 1054 } 1055