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 /* 253 * The 'for' command does not set exitstatus, so the value 254 * now in exitstatus is from the last command executed in 255 * the 'for' loop. That exit value had been tested (wrt 256 * 'sh -e' checking) while processing that command, and 257 * it should not be re-tested here. 258 */ 259 flags |= EV_TESTED; 260 break; 261 case NCASE: 262 evalcase(n, flags); 263 /* 264 * The 'case' command does not set exitstatus, so the value 265 * now in exitstatus is from the last command executed in 266 * the 'case' block. That exit value had been tested (wrt 267 * 'sh -e' checking) while processing that command, and 268 * it should not be re-tested here. 269 */ 270 flags |= EV_TESTED; 271 break; 272 case NDEFUN: 273 defun(n->narg.text, n->narg.next); 274 exitstatus = 0; 275 break; 276 case NNOT: 277 evaltree(n->nnot.com, EV_TESTED); 278 exitstatus = !exitstatus; 279 break; 280 281 case NPIPE: 282 evalpipe(n); 283 break; 284 case NCMD: 285 evalcommand(n, flags, (struct backcmd *)NULL); 286 break; 287 default: 288 out1fmt("Node type = %d\n", n->type); 289 flushout(&output); 290 break; 291 } 292 out: 293 if (pendingsigs) 294 dotrap(); 295 /* 296 * XXX - Like "!(n->type == NSEMI)", more types will probably 297 * need to be excluded from this test. It's probably better 298 * to set or unset EV_TESTED in the loop above than to bloat 299 * the conditional here. 300 */ 301 if ((flags & EV_EXIT) || (eflag && exitstatus 302 && !(flags & EV_TESTED) && !(n->type == NSEMI))) 303 exitshell(exitstatus); 304 } 305 306 307 STATIC void 308 evalloop(n) 309 union node *n; 310 { 311 int status; 312 313 loopnest++; 314 status = 0; 315 for (;;) { 316 evaltree(n->nbinary.ch1, EV_TESTED); 317 if (evalskip) { 318 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 319 evalskip = 0; 320 continue; 321 } 322 if (evalskip == SKIPBREAK && --skipcount <= 0) 323 evalskip = 0; 324 break; 325 } 326 if (n->type == NWHILE) { 327 if (exitstatus != 0) 328 break; 329 } else { 330 if (exitstatus == 0) 331 break; 332 } 333 evaltree(n->nbinary.ch2, 0); 334 status = exitstatus; 335 if (evalskip) 336 goto skipping; 337 } 338 loopnest--; 339 exitstatus = status; 340 } 341 342 343 344 STATIC void 345 evalfor(n) 346 union node *n; 347 { 348 struct arglist arglist; 349 union node *argp; 350 struct strlist *sp; 351 struct stackmark smark; 352 353 setstackmark(&smark); 354 arglist.lastp = &arglist.list; 355 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 356 oexitstatus = exitstatus; 357 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 358 if (evalskip) 359 goto out; 360 } 361 *arglist.lastp = NULL; 362 363 exitstatus = 0; 364 loopnest++; 365 for (sp = arglist.list ; sp ; sp = sp->next) { 366 setvar(n->nfor.var, sp->text, 0); 367 evaltree(n->nfor.body, 0); 368 if (evalskip) { 369 if (evalskip == SKIPCONT && --skipcount <= 0) { 370 evalskip = 0; 371 continue; 372 } 373 if (evalskip == SKIPBREAK && --skipcount <= 0) 374 evalskip = 0; 375 break; 376 } 377 } 378 loopnest--; 379 out: 380 popstackmark(&smark); 381 } 382 383 384 385 STATIC void 386 evalcase(n, flags) 387 union node *n; 388 int flags; 389 { 390 union node *cp; 391 union node *patp; 392 struct arglist arglist; 393 struct stackmark smark; 394 395 setstackmark(&smark); 396 arglist.lastp = &arglist.list; 397 oexitstatus = exitstatus; 398 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 399 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 400 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 401 if (casematch(patp, arglist.list->text)) { 402 if (evalskip == 0) { 403 evaltree(cp->nclist.body, flags); 404 } 405 goto out; 406 } 407 } 408 } 409 out: 410 popstackmark(&smark); 411 } 412 413 414 415 /* 416 * Kick off a subshell to evaluate a tree. 417 */ 418 419 STATIC void 420 evalsubshell(n, flags) 421 union node *n; 422 int flags; 423 { 424 struct job *jp; 425 int backgnd = (n->type == NBACKGND); 426 427 expredir(n->nredir.redirect); 428 jp = makejob(n, 1); 429 if (forkshell(jp, n, backgnd) == 0) { 430 if (backgnd) 431 flags &=~ EV_TESTED; 432 redirect(n->nredir.redirect, 0); 433 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 434 } 435 if (! backgnd) { 436 INTOFF; 437 exitstatus = waitforjob(jp, (int *)NULL); 438 INTON; 439 } 440 } 441 442 443 444 /* 445 * Compute the names of the files in a redirection list. 446 */ 447 448 STATIC void 449 expredir(n) 450 union node *n; 451 { 452 union node *redir; 453 454 for (redir = n ; redir ; redir = redir->nfile.next) { 455 struct arglist fn; 456 fn.lastp = &fn.list; 457 oexitstatus = exitstatus; 458 switch (redir->type) { 459 case NFROM: 460 case NTO: 461 case NFROMTO: 462 case NAPPEND: 463 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 464 redir->nfile.expfname = fn.list->text; 465 break; 466 case NFROMFD: 467 case NTOFD: 468 if (redir->ndup.vname) { 469 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 470 fixredir(redir, fn.list->text, 1); 471 } 472 break; 473 } 474 } 475 } 476 477 478 479 /* 480 * Evaluate a pipeline. All the processes in the pipeline are children 481 * of the process creating the pipeline. (This differs from some versions 482 * of the shell, which make the last process in a pipeline the parent 483 * of all the rest.) 484 */ 485 486 STATIC void 487 evalpipe(n) 488 union node *n; 489 { 490 struct job *jp; 491 struct nodelist *lp; 492 int pipelen; 493 int prevfd; 494 int pip[2]; 495 496 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 497 pipelen = 0; 498 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 499 pipelen++; 500 INTOFF; 501 jp = makejob(n, pipelen); 502 prevfd = -1; 503 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 504 prehash(lp->n); 505 pip[1] = -1; 506 if (lp->next) { 507 if (pipe(pip) < 0) { 508 close(prevfd); 509 error("Pipe call failed: %s", strerror(errno)); 510 } 511 } 512 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 513 INTON; 514 if (prevfd > 0) { 515 close(0); 516 copyfd(prevfd, 0); 517 close(prevfd); 518 } 519 if (pip[1] >= 0) { 520 if (!(prevfd >= 0 && pip[0] == 0)) 521 close(pip[0]); 522 if (pip[1] != 1) { 523 close(1); 524 copyfd(pip[1], 1); 525 close(pip[1]); 526 } 527 } 528 evaltree(lp->n, EV_EXIT); 529 } 530 if (prevfd >= 0) 531 close(prevfd); 532 prevfd = pip[0]; 533 close(pip[1]); 534 } 535 INTON; 536 if (n->npipe.backgnd == 0) { 537 INTOFF; 538 exitstatus = waitforjob(jp, (int *)NULL); 539 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 540 INTON; 541 } 542 } 543 544 545 546 /* 547 * Execute a command inside back quotes. If it's a builtin command, we 548 * want to save its output in a block obtained from malloc. Otherwise 549 * we fork off a subprocess and get the output of the command via a pipe. 550 * Should be called with interrupts off. 551 */ 552 553 void 554 evalbackcmd(n, result) 555 union node *n; 556 struct backcmd *result; 557 { 558 int pip[2]; 559 struct job *jp; 560 struct stackmark smark; /* unnecessary */ 561 562 setstackmark(&smark); 563 result->fd = -1; 564 result->buf = NULL; 565 result->nleft = 0; 566 result->jp = NULL; 567 if (n == NULL) { 568 exitstatus = 0; 569 goto out; 570 } 571 if (n->type == NCMD) { 572 exitstatus = oexitstatus; 573 evalcommand(n, EV_BACKCMD, result); 574 } else { 575 exitstatus = 0; 576 if (pipe(pip) < 0) 577 error("Pipe call failed: %s", strerror(errno)); 578 jp = makejob(n, 1); 579 if (forkshell(jp, n, FORK_NOJOB) == 0) { 580 FORCEINTON; 581 close(pip[0]); 582 if (pip[1] != 1) { 583 close(1); 584 copyfd(pip[1], 1); 585 close(pip[1]); 586 } 587 evaltree(n, EV_EXIT); 588 } 589 close(pip[1]); 590 result->fd = pip[0]; 591 result->jp = jp; 592 } 593 out: 594 popstackmark(&smark); 595 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 596 result->fd, result->buf, result->nleft, result->jp)); 597 } 598 599 600 601 /* 602 * Execute a simple command. 603 */ 604 605 STATIC void 606 evalcommand(cmd, flags, backcmd) 607 union node *cmd; 608 int flags; 609 struct backcmd *backcmd; 610 { 611 struct stackmark smark; 612 union node *argp; 613 struct arglist arglist; 614 struct arglist varlist; 615 char **argv; 616 int argc; 617 char **envp; 618 int varflag; 619 struct strlist *sp; 620 int mode; 621 int pip[2]; 622 struct cmdentry cmdentry; 623 struct job *jp; 624 struct jmploc jmploc; 625 struct jmploc *volatile savehandler; 626 char *volatile savecmdname; 627 volatile struct shparam saveparam; 628 struct localvar *volatile savelocalvars; 629 volatile int e; 630 char *lastarg; 631 int realstatus; 632 int do_clearcmdentry; 633 #if __GNUC__ 634 /* Avoid longjmp clobbering */ 635 (void) &argv; 636 (void) &argc; 637 (void) &lastarg; 638 (void) &flags; 639 (void) &do_clearcmdentry; 640 #endif 641 642 /* First expand the arguments. */ 643 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 644 setstackmark(&smark); 645 arglist.lastp = &arglist.list; 646 varlist.lastp = &varlist.list; 647 varflag = 1; 648 do_clearcmdentry = 0; 649 oexitstatus = exitstatus; 650 exitstatus = 0; 651 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 652 char *p = argp->narg.text; 653 if (varflag && is_name(*p)) { 654 do { 655 p++; 656 } while (is_in_name(*p)); 657 if (*p == '=') { 658 expandarg(argp, &varlist, EXP_VARTILDE); 659 continue; 660 } 661 } 662 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 663 varflag = 0; 664 } 665 *arglist.lastp = NULL; 666 *varlist.lastp = NULL; 667 expredir(cmd->ncmd.redirect); 668 argc = 0; 669 for (sp = arglist.list ; sp ; sp = sp->next) 670 argc++; 671 argv = stalloc(sizeof (char *) * (argc + 1)); 672 673 for (sp = arglist.list ; sp ; sp = sp->next) { 674 TRACE(("evalcommand arg: %s\n", sp->text)); 675 *argv++ = sp->text; 676 } 677 *argv = NULL; 678 lastarg = NULL; 679 if (iflag && funcnest == 0 && argc > 0) 680 lastarg = argv[-1]; 681 argv -= argc; 682 683 /* Print the command if xflag is set. */ 684 if (xflag) { 685 outc('+', &errout); 686 for (sp = varlist.list ; sp ; sp = sp->next) { 687 outc(' ', &errout); 688 out2str(sp->text); 689 } 690 for (sp = arglist.list ; sp ; sp = sp->next) { 691 outc(' ', &errout); 692 out2str(sp->text); 693 } 694 outc('\n', &errout); 695 flushout(&errout); 696 } 697 698 /* Now locate the command. */ 699 if (argc == 0) { 700 cmdentry.cmdtype = CMDBUILTIN; 701 cmdentry.u.index = BLTINCMD; 702 } else { 703 static const char PATH[] = "PATH="; 704 char *path = pathval(); 705 706 /* 707 * Modify the command lookup path, if a PATH= assignment 708 * is present 709 */ 710 for (sp = varlist.list ; sp ; sp = sp->next) 711 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 712 path = sp->text + sizeof(PATH) - 1; 713 /* 714 * On `PATH=... command`, we need to make 715 * sure that the command isn't using the 716 * non-updated hash table of the outer PATH 717 * setting and we need to make sure that 718 * the hash table isn't filled with items 719 * from the temporary setting. 720 * 721 * It would be better to forbit using and 722 * updating the table while this command 723 * runs, by the command finding mechanism 724 * is heavily integrated with hash handling, 725 * so we just delete the hash before and after 726 * the command runs. Partly deleting like 727 * changepatch() does doesn't seem worth the 728 * bookinging effort, since most such runs add 729 * diretories in front of the new PATH. 730 */ 731 clearcmdentry(0); 732 do_clearcmdentry = 1; 733 } 734 735 find_command(argv[0], &cmdentry, 1, path); 736 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 737 exitstatus = 127; 738 flushout(&errout); 739 return; 740 } 741 /* implement the bltin builtin here */ 742 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 743 for (;;) { 744 argv++; 745 if (--argc == 0) 746 break; 747 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 748 outfmt(&errout, "%s: not found\n", *argv); 749 exitstatus = 127; 750 flushout(&errout); 751 return; 752 } 753 if (cmdentry.u.index != BLTINCMD) 754 break; 755 } 756 } 757 } 758 759 /* Fork off a child process if necessary. */ 760 if (cmd->ncmd.backgnd 761 || (cmdentry.cmdtype == CMDNORMAL 762 && ((flags & EV_EXIT) == 0 || Tflag)) 763 || ((flags & EV_BACKCMD) != 0 764 && (cmdentry.cmdtype != CMDBUILTIN 765 || cmdentry.u.index == CDCMD 766 || cmdentry.u.index == DOTCMD 767 || cmdentry.u.index == EVALCMD))) { 768 jp = makejob(cmd, 1); 769 mode = cmd->ncmd.backgnd; 770 if (flags & EV_BACKCMD) { 771 mode = FORK_NOJOB; 772 if (pipe(pip) < 0) 773 error("Pipe call failed: %s", strerror(errno)); 774 } 775 if (forkshell(jp, cmd, mode) != 0) 776 goto parent; /* at end of routine */ 777 if (flags & EV_BACKCMD) { 778 FORCEINTON; 779 close(pip[0]); 780 if (pip[1] != 1) { 781 close(1); 782 copyfd(pip[1], 1); 783 close(pip[1]); 784 } 785 } 786 flags |= EV_EXIT; 787 } 788 789 /* This is the child process if a fork occurred. */ 790 /* Execute the command. */ 791 if (cmdentry.cmdtype == CMDFUNCTION) { 792 #ifdef DEBUG 793 trputs("Shell function: "); trargs(argv); 794 #endif 795 redirect(cmd->ncmd.redirect, REDIR_PUSH); 796 saveparam = shellparam; 797 shellparam.malloc = 0; 798 shellparam.reset = 1; 799 shellparam.nparam = argc - 1; 800 shellparam.p = argv + 1; 801 shellparam.optnext = NULL; 802 INTOFF; 803 savelocalvars = localvars; 804 localvars = NULL; 805 INTON; 806 if (setjmp(jmploc.loc)) { 807 if (exception == EXSHELLPROC) 808 freeparam((struct shparam *)&saveparam); 809 else { 810 freeparam(&shellparam); 811 shellparam = saveparam; 812 } 813 poplocalvars(); 814 localvars = savelocalvars; 815 handler = savehandler; 816 longjmp(handler->loc, 1); 817 } 818 savehandler = handler; 819 handler = &jmploc; 820 for (sp = varlist.list ; sp ; sp = sp->next) 821 mklocal(sp->text); 822 funcnest++; 823 if (flags & EV_TESTED) 824 evaltree(cmdentry.u.func, EV_TESTED); 825 else 826 evaltree(cmdentry.u.func, 0); 827 funcnest--; 828 INTOFF; 829 poplocalvars(); 830 localvars = savelocalvars; 831 freeparam(&shellparam); 832 shellparam = saveparam; 833 handler = savehandler; 834 popredir(); 835 INTON; 836 if (evalskip == SKIPFUNC) { 837 evalskip = 0; 838 skipcount = 0; 839 } 840 if (flags & EV_EXIT) 841 exitshell(exitstatus); 842 } else if (cmdentry.cmdtype == CMDBUILTIN) { 843 #ifdef DEBUG 844 trputs("builtin command: "); trargs(argv); 845 #endif 846 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 847 if (flags == EV_BACKCMD) { 848 memout.nleft = 0; 849 memout.nextc = memout.buf; 850 memout.bufsize = 64; 851 mode |= REDIR_BACKQ; 852 } 853 redirect(cmd->ncmd.redirect, mode); 854 savecmdname = commandname; 855 cmdenviron = varlist.list; 856 e = -1; 857 if (setjmp(jmploc.loc)) { 858 e = exception; 859 exitstatus = (e == EXINT)? SIGINT+128 : 2; 860 goto cmddone; 861 } 862 savehandler = handler; 863 handler = &jmploc; 864 commandname = argv[0]; 865 argptr = argv + 1; 866 optptr = NULL; /* initialize nextopt */ 867 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 868 flushall(); 869 cmddone: 870 cmdenviron = NULL; 871 out1 = &output; 872 out2 = &errout; 873 freestdout(); 874 if (e != EXSHELLPROC) { 875 commandname = savecmdname; 876 if (flags & EV_EXIT) { 877 exitshell(exitstatus); 878 } 879 } 880 handler = savehandler; 881 if (e != -1) { 882 if ((e != EXERROR && e != EXEXEC) 883 || cmdentry.u.index == BLTINCMD 884 || cmdentry.u.index == DOTCMD 885 || cmdentry.u.index == EVALCMD 886 #ifndef NO_HISTORY 887 || cmdentry.u.index == HISTCMD 888 #endif 889 || cmdentry.u.index == EXECCMD) 890 exraise(e); 891 FORCEINTON; 892 } 893 if (cmdentry.u.index != EXECCMD) 894 popredir(); 895 if (flags == EV_BACKCMD) { 896 backcmd->buf = memout.buf; 897 backcmd->nleft = memout.nextc - memout.buf; 898 memout.buf = NULL; 899 } 900 } else { 901 #ifdef DEBUG 902 trputs("normal command: "); trargs(argv); 903 #endif 904 clearredir(); 905 redirect(cmd->ncmd.redirect, 0); 906 for (sp = varlist.list ; sp ; sp = sp->next) 907 setvareq(sp->text, VEXPORT|VSTACK); 908 envp = environment(); 909 shellexec(argv, envp, pathval(), cmdentry.u.index); 910 /*NOTREACHED*/ 911 } 912 goto out; 913 914 parent: /* parent process gets here (if we forked) */ 915 if (mode == 0) { /* argument to fork */ 916 INTOFF; 917 exitstatus = waitforjob(jp, &realstatus); 918 INTON; 919 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 920 evalskip = SKIPBREAK; 921 skipcount = loopnest; 922 } 923 } else if (mode == 2) { 924 backcmd->fd = pip[0]; 925 close(pip[1]); 926 backcmd->jp = jp; 927 } 928 929 out: 930 if (lastarg) 931 setvar("_", lastarg, 0); 932 if (do_clearcmdentry) 933 clearcmdentry(0); 934 popstackmark(&smark); 935 } 936 937 938 939 /* 940 * Search for a command. This is called before we fork so that the 941 * location of the command will be available in the parent as well as 942 * the child. The check for "goodname" is an overly conservative 943 * check that the name will not be subject to expansion. 944 */ 945 946 STATIC void 947 prehash(n) 948 union node *n; 949 { 950 struct cmdentry entry; 951 952 if (n->type == NCMD && n->ncmd.args) 953 if (goodname(n->ncmd.args->narg.text)) 954 find_command(n->ncmd.args->narg.text, &entry, 0, 955 pathval()); 956 } 957 958 959 960 /* 961 * Builtin commands. Builtin commands whose functions are closely 962 * tied to evaluation are implemented here. 963 */ 964 965 /* 966 * No command given, or a bltin command with no arguments. Set the 967 * specified variables. 968 */ 969 970 int 971 bltincmd(argc, argv) 972 int argc __unused; 973 char **argv __unused; 974 { 975 listsetvar(cmdenviron); 976 /* 977 * Preserve exitstatus of a previous possible redirection 978 * as POSIX mandates 979 */ 980 return exitstatus; 981 } 982 983 984 /* 985 * Handle break and continue commands. Break, continue, and return are 986 * all handled by setting the evalskip flag. The evaluation routines 987 * above all check this flag, and if it is set they start skipping 988 * commands rather than executing them. The variable skipcount is 989 * the number of loops to break/continue, or the number of function 990 * levels to return. (The latter is always 1.) It should probably 991 * be an error to break out of more loops than exist, but it isn't 992 * in the standard shell so we don't make it one here. 993 */ 994 995 int 996 breakcmd(argc, argv) 997 int argc; 998 char **argv; 999 { 1000 int n = argc > 1 ? number(argv[1]) : 1; 1001 1002 if (n > loopnest) 1003 n = loopnest; 1004 if (n > 0) { 1005 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1006 skipcount = n; 1007 } 1008 return 0; 1009 } 1010 1011 1012 /* 1013 * The return command. 1014 */ 1015 1016 int 1017 returncmd(argc, argv) 1018 int argc; 1019 char **argv; 1020 { 1021 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1022 1023 if (funcnest) { 1024 evalskip = SKIPFUNC; 1025 skipcount = 1; 1026 } else { 1027 /* skip the rest of the file */ 1028 evalskip = SKIPFILE; 1029 skipcount = 1; 1030 } 1031 return ret; 1032 } 1033 1034 1035 int 1036 falsecmd(argc, argv) 1037 int argc __unused; 1038 char **argv __unused; 1039 { 1040 return 1; 1041 } 1042 1043 1044 int 1045 truecmd(argc, argv) 1046 int argc __unused; 1047 char **argv __unused; 1048 { 1049 return 0; 1050 } 1051 1052 1053 int 1054 execcmd(argc, argv) 1055 int argc; 1056 char **argv; 1057 { 1058 if (argc > 1) { 1059 struct strlist *sp; 1060 1061 iflag = 0; /* exit on error */ 1062 mflag = 0; 1063 optschanged(); 1064 for (sp = cmdenviron; sp ; sp = sp->next) 1065 setvareq(sp->text, VEXPORT|VSTACK); 1066 shellexec(argv + 1, environment(), pathval(), 0); 1067 1068 } 1069 return 0; 1070 } 1071