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 NAPPEND: 446 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 447 redir->nfile.expfname = fn.list->text; 448 break; 449 case NFROMFD: 450 case NTOFD: 451 if (redir->ndup.vname) { 452 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 453 fixredir(redir, fn.list->text, 1); 454 } 455 break; 456 } 457 } 458 } 459 460 461 462 /* 463 * Evaluate a pipeline. All the processes in the pipeline are children 464 * of the process creating the pipeline. (This differs from some versions 465 * of the shell, which make the last process in a pipeline the parent 466 * of all the rest.) 467 */ 468 469 STATIC void 470 evalpipe(n) 471 union node *n; 472 { 473 struct job *jp; 474 struct nodelist *lp; 475 int pipelen; 476 int prevfd; 477 int pip[2]; 478 479 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 480 pipelen = 0; 481 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 482 pipelen++; 483 INTOFF; 484 jp = makejob(n, pipelen); 485 prevfd = -1; 486 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 487 prehash(lp->n); 488 pip[1] = -1; 489 if (lp->next) { 490 if (pipe(pip) < 0) { 491 close(prevfd); 492 error("Pipe call failed: %s", strerror(errno)); 493 } 494 } 495 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 496 INTON; 497 if (prevfd > 0) { 498 close(0); 499 copyfd(prevfd, 0); 500 close(prevfd); 501 } 502 if (pip[1] >= 0) { 503 if (!(prevfd >= 0 && pip[0] == 0)) 504 close(pip[0]); 505 if (pip[1] != 1) { 506 close(1); 507 copyfd(pip[1], 1); 508 close(pip[1]); 509 } 510 } 511 evaltree(lp->n, EV_EXIT); 512 } 513 if (prevfd >= 0) 514 close(prevfd); 515 prevfd = pip[0]; 516 close(pip[1]); 517 } 518 INTON; 519 if (n->npipe.backgnd == 0) { 520 INTOFF; 521 exitstatus = waitforjob(jp, (int *)NULL); 522 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 523 INTON; 524 } 525 } 526 527 528 529 /* 530 * Execute a command inside back quotes. If it's a builtin command, we 531 * want to save its output in a block obtained from malloc. Otherwise 532 * we fork off a subprocess and get the output of the command via a pipe. 533 * Should be called with interrupts off. 534 */ 535 536 void 537 evalbackcmd(n, result) 538 union node *n; 539 struct backcmd *result; 540 { 541 int pip[2]; 542 struct job *jp; 543 struct stackmark smark; /* unnecessary */ 544 545 setstackmark(&smark); 546 result->fd = -1; 547 result->buf = NULL; 548 result->nleft = 0; 549 result->jp = NULL; 550 if (n == NULL) { 551 exitstatus = 0; 552 goto out; 553 } 554 if (n->type == NCMD) { 555 exitstatus = oexitstatus; 556 evalcommand(n, EV_BACKCMD, result); 557 } else { 558 exitstatus = 0; 559 if (pipe(pip) < 0) 560 error("Pipe call failed: %s", strerror(errno)); 561 jp = makejob(n, 1); 562 if (forkshell(jp, n, FORK_NOJOB) == 0) { 563 FORCEINTON; 564 close(pip[0]); 565 if (pip[1] != 1) { 566 close(1); 567 copyfd(pip[1], 1); 568 close(pip[1]); 569 } 570 evaltree(n, EV_EXIT); 571 } 572 close(pip[1]); 573 result->fd = pip[0]; 574 result->jp = jp; 575 } 576 out: 577 popstackmark(&smark); 578 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 579 result->fd, result->buf, result->nleft, result->jp)); 580 } 581 582 583 584 /* 585 * Execute a simple command. 586 */ 587 588 STATIC void 589 evalcommand(cmd, flags, backcmd) 590 union node *cmd; 591 int flags; 592 struct backcmd *backcmd; 593 { 594 struct stackmark smark; 595 union node *argp; 596 struct arglist arglist; 597 struct arglist varlist; 598 char **argv; 599 int argc; 600 char **envp; 601 int varflag; 602 struct strlist *sp; 603 int mode; 604 int pip[2]; 605 struct cmdentry cmdentry; 606 struct job *jp; 607 struct jmploc jmploc; 608 struct jmploc *volatile savehandler; 609 char *volatile savecmdname; 610 volatile struct shparam saveparam; 611 struct localvar *volatile savelocalvars; 612 volatile int e; 613 char *lastarg; 614 int realstatus; 615 int do_clearcmdentry; 616 #if __GNUC__ 617 /* Avoid longjmp clobbering */ 618 (void) &argv; 619 (void) &argc; 620 (void) &lastarg; 621 (void) &flags; 622 (void) &do_clearcmdentry; 623 #endif 624 625 /* First expand the arguments. */ 626 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 627 setstackmark(&smark); 628 arglist.lastp = &arglist.list; 629 varlist.lastp = &varlist.list; 630 varflag = 1; 631 do_clearcmdentry = 0; 632 oexitstatus = exitstatus; 633 exitstatus = 0; 634 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 635 char *p = argp->narg.text; 636 if (varflag && is_name(*p)) { 637 do { 638 p++; 639 } while (is_in_name(*p)); 640 if (*p == '=') { 641 expandarg(argp, &varlist, EXP_VARTILDE); 642 continue; 643 } 644 } 645 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 646 varflag = 0; 647 } 648 *arglist.lastp = NULL; 649 *varlist.lastp = NULL; 650 expredir(cmd->ncmd.redirect); 651 argc = 0; 652 for (sp = arglist.list ; sp ; sp = sp->next) 653 argc++; 654 argv = stalloc(sizeof (char *) * (argc + 1)); 655 656 for (sp = arglist.list ; sp ; sp = sp->next) { 657 TRACE(("evalcommand arg: %s\n", sp->text)); 658 *argv++ = sp->text; 659 } 660 *argv = NULL; 661 lastarg = NULL; 662 if (iflag && funcnest == 0 && argc > 0) 663 lastarg = argv[-1]; 664 argv -= argc; 665 666 /* Print the command if xflag is set. */ 667 if (xflag) { 668 outc('+', &errout); 669 for (sp = varlist.list ; sp ; sp = sp->next) { 670 outc(' ', &errout); 671 out2str(sp->text); 672 } 673 for (sp = arglist.list ; sp ; sp = sp->next) { 674 outc(' ', &errout); 675 out2str(sp->text); 676 } 677 outc('\n', &errout); 678 flushout(&errout); 679 } 680 681 /* Now locate the command. */ 682 if (argc == 0) { 683 cmdentry.cmdtype = CMDBUILTIN; 684 cmdentry.u.index = BLTINCMD; 685 } else { 686 static const char PATH[] = "PATH="; 687 char *path = pathval(); 688 689 /* 690 * Modify the command lookup path, if a PATH= assignment 691 * is present 692 */ 693 for (sp = varlist.list ; sp ; sp = sp->next) 694 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 695 path = sp->text + sizeof(PATH) - 1; 696 /* 697 * On `PATH=... command`, we need to make 698 * sure that the command isn't using the 699 * non-updated hash table of the outer PATH 700 * setting and we need to make sure that 701 * the hash table isn't filled with items 702 * from the temporary setting. 703 * 704 * It would be better to forbit using and 705 * updating the table while this command 706 * runs, by the command finding mechanism 707 * is heavily integrated with hash handling, 708 * so we just delete the hash before and after 709 * the command runs. Partly deleting like 710 * changepatch() does doesn't seem worth the 711 * bookinging effort, since most such runs add 712 * diretories in front of the new PATH. 713 */ 714 clearcmdentry(0); 715 do_clearcmdentry = 1; 716 } 717 718 find_command(argv[0], &cmdentry, 1, path); 719 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 720 exitstatus = 127; 721 flushout(&errout); 722 return; 723 } 724 /* implement the bltin builtin here */ 725 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 726 for (;;) { 727 argv++; 728 if (--argc == 0) 729 break; 730 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 731 outfmt(&errout, "%s: not found\n", *argv); 732 exitstatus = 127; 733 flushout(&errout); 734 return; 735 } 736 if (cmdentry.u.index != BLTINCMD) 737 break; 738 } 739 } 740 } 741 742 /* Fork off a child process if necessary. */ 743 if (cmd->ncmd.backgnd 744 || (cmdentry.cmdtype == CMDNORMAL 745 && ((flags & EV_EXIT) == 0 || Tflag)) 746 || ((flags & EV_BACKCMD) != 0 747 && (cmdentry.cmdtype != CMDBUILTIN 748 || cmdentry.u.index == CDCMD 749 || cmdentry.u.index == DOTCMD 750 || cmdentry.u.index == EVALCMD))) { 751 jp = makejob(cmd, 1); 752 mode = cmd->ncmd.backgnd; 753 if (flags & EV_BACKCMD) { 754 mode = FORK_NOJOB; 755 if (pipe(pip) < 0) 756 error("Pipe call failed: %s", strerror(errno)); 757 } 758 if (forkshell(jp, cmd, mode) != 0) 759 goto parent; /* at end of routine */ 760 if (flags & EV_BACKCMD) { 761 FORCEINTON; 762 close(pip[0]); 763 if (pip[1] != 1) { 764 close(1); 765 copyfd(pip[1], 1); 766 close(pip[1]); 767 } 768 } 769 flags |= EV_EXIT; 770 } 771 772 /* This is the child process if a fork occurred. */ 773 /* Execute the command. */ 774 if (cmdentry.cmdtype == CMDFUNCTION) { 775 #ifdef DEBUG 776 trputs("Shell function: "); trargs(argv); 777 #endif 778 redirect(cmd->ncmd.redirect, REDIR_PUSH); 779 saveparam = shellparam; 780 shellparam.malloc = 0; 781 shellparam.reset = 1; 782 shellparam.nparam = argc - 1; 783 shellparam.p = argv + 1; 784 shellparam.optnext = NULL; 785 INTOFF; 786 savelocalvars = localvars; 787 localvars = NULL; 788 INTON; 789 if (setjmp(jmploc.loc)) { 790 if (exception == EXSHELLPROC) 791 freeparam((struct shparam *)&saveparam); 792 else { 793 freeparam(&shellparam); 794 shellparam = saveparam; 795 } 796 poplocalvars(); 797 localvars = savelocalvars; 798 handler = savehandler; 799 longjmp(handler->loc, 1); 800 } 801 savehandler = handler; 802 handler = &jmploc; 803 for (sp = varlist.list ; sp ; sp = sp->next) 804 mklocal(sp->text); 805 funcnest++; 806 if (flags & EV_TESTED) 807 evaltree(cmdentry.u.func, EV_TESTED); 808 else 809 evaltree(cmdentry.u.func, 0); 810 funcnest--; 811 INTOFF; 812 poplocalvars(); 813 localvars = savelocalvars; 814 freeparam(&shellparam); 815 shellparam = saveparam; 816 handler = savehandler; 817 popredir(); 818 INTON; 819 if (evalskip == SKIPFUNC) { 820 evalskip = 0; 821 skipcount = 0; 822 } 823 if (flags & EV_EXIT) 824 exitshell(exitstatus); 825 } else if (cmdentry.cmdtype == CMDBUILTIN) { 826 #ifdef DEBUG 827 trputs("builtin command: "); trargs(argv); 828 #endif 829 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 830 if (flags == EV_BACKCMD) { 831 memout.nleft = 0; 832 memout.nextc = memout.buf; 833 memout.bufsize = 64; 834 mode |= REDIR_BACKQ; 835 } 836 redirect(cmd->ncmd.redirect, mode); 837 savecmdname = commandname; 838 cmdenviron = varlist.list; 839 e = -1; 840 if (setjmp(jmploc.loc)) { 841 e = exception; 842 exitstatus = (e == EXINT)? SIGINT+128 : 2; 843 goto cmddone; 844 } 845 savehandler = handler; 846 handler = &jmploc; 847 commandname = argv[0]; 848 argptr = argv + 1; 849 optptr = NULL; /* initialize nextopt */ 850 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 851 flushall(); 852 cmddone: 853 out1 = &output; 854 out2 = &errout; 855 freestdout(); 856 if (e != EXSHELLPROC) { 857 commandname = savecmdname; 858 if (flags & EV_EXIT) { 859 exitshell(exitstatus); 860 } 861 } 862 handler = savehandler; 863 if (e != -1) { 864 if ((e != EXERROR && e != EXEXEC) 865 || cmdentry.u.index == BLTINCMD 866 || cmdentry.u.index == DOTCMD 867 || cmdentry.u.index == EVALCMD 868 #ifndef NO_HISTORY 869 || cmdentry.u.index == HISTCMD 870 #endif 871 || cmdentry.u.index == EXECCMD) 872 exraise(e); 873 FORCEINTON; 874 } 875 if (cmdentry.u.index != EXECCMD) 876 popredir(); 877 if (flags == EV_BACKCMD) { 878 backcmd->buf = memout.buf; 879 backcmd->nleft = memout.nextc - memout.buf; 880 memout.buf = NULL; 881 } 882 } else { 883 #ifdef DEBUG 884 trputs("normal command: "); trargs(argv); 885 #endif 886 clearredir(); 887 redirect(cmd->ncmd.redirect, 0); 888 for (sp = varlist.list ; sp ; sp = sp->next) 889 setvareq(sp->text, VEXPORT|VSTACK); 890 envp = environment(); 891 shellexec(argv, envp, pathval(), cmdentry.u.index); 892 /*NOTREACHED*/ 893 } 894 goto out; 895 896 parent: /* parent process gets here (if we forked) */ 897 if (mode == 0) { /* argument to fork */ 898 INTOFF; 899 exitstatus = waitforjob(jp, &realstatus); 900 INTON; 901 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 902 evalskip = SKIPBREAK; 903 skipcount = loopnest; 904 } 905 } else if (mode == 2) { 906 backcmd->fd = pip[0]; 907 close(pip[1]); 908 backcmd->jp = jp; 909 } 910 911 out: 912 if (lastarg) 913 setvar("_", lastarg, 0); 914 if (do_clearcmdentry) 915 clearcmdentry(0); 916 popstackmark(&smark); 917 } 918 919 920 921 /* 922 * Search for a command. This is called before we fork so that the 923 * location of the command will be available in the parent as well as 924 * the child. The check for "goodname" is an overly conservative 925 * check that the name will not be subject to expansion. 926 */ 927 928 STATIC void 929 prehash(n) 930 union node *n; 931 { 932 struct cmdentry entry; 933 934 if (n->type == NCMD && n->ncmd.args) 935 if (goodname(n->ncmd.args->narg.text)) 936 find_command(n->ncmd.args->narg.text, &entry, 0, 937 pathval()); 938 } 939 940 941 942 /* 943 * Builtin commands. Builtin commands whose functions are closely 944 * tied to evaluation are implemented here. 945 */ 946 947 /* 948 * No command given, or a bltin command with no arguments. Set the 949 * specified variables. 950 */ 951 952 int 953 bltincmd(argc, argv) 954 int argc __unused; 955 char **argv __unused; 956 { 957 listsetvar(cmdenviron); 958 /* 959 * Preserve exitstatus of a previous possible redirection 960 * as POSIX mandates 961 */ 962 return exitstatus; 963 } 964 965 966 /* 967 * Handle break and continue commands. Break, continue, and return are 968 * all handled by setting the evalskip flag. The evaluation routines 969 * above all check this flag, and if it is set they start skipping 970 * commands rather than executing them. The variable skipcount is 971 * the number of loops to break/continue, or the number of function 972 * levels to return. (The latter is always 1.) It should probably 973 * be an error to break out of more loops than exist, but it isn't 974 * in the standard shell so we don't make it one here. 975 */ 976 977 int 978 breakcmd(argc, argv) 979 int argc; 980 char **argv; 981 { 982 int n = argc > 1 ? number(argv[1]) : 1; 983 984 if (n > loopnest) 985 n = loopnest; 986 if (n > 0) { 987 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 988 skipcount = n; 989 } 990 return 0; 991 } 992 993 994 /* 995 * The return command. 996 */ 997 998 int 999 returncmd(argc, argv) 1000 int argc; 1001 char **argv; 1002 { 1003 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1004 1005 if (funcnest) { 1006 evalskip = SKIPFUNC; 1007 skipcount = 1; 1008 } else { 1009 /* skip the rest of the file */ 1010 evalskip = SKIPFILE; 1011 skipcount = 1; 1012 } 1013 return ret; 1014 } 1015 1016 1017 int 1018 falsecmd(argc, argv) 1019 int argc __unused; 1020 char **argv __unused; 1021 { 1022 return 1; 1023 } 1024 1025 1026 int 1027 truecmd(argc, argv) 1028 int argc __unused; 1029 char **argv __unused; 1030 { 1031 return 0; 1032 } 1033 1034 1035 int 1036 execcmd(argc, argv) 1037 int argc; 1038 char **argv; 1039 { 1040 if (argc > 1) { 1041 struct strlist *sp; 1042 1043 iflag = 0; /* exit on error */ 1044 mflag = 0; 1045 optschanged(); 1046 for (sp = cmdenviron; sp ; sp = sp->next) 1047 setvareq(sp->text, VEXPORT|VSTACK); 1048 shellexec(argv + 1, environment(), pathval(), 0); 1049 1050 } 1051 return 0; 1052 } 1053