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 #endif /* not lint */ 42 #include <sys/cdefs.h> 43 __FBSDID("$FreeBSD$"); 44 45 #include <paths.h> 46 #include <signal.h> 47 #include <unistd.h> 48 #include <sys/wait.h> /* For WIFSIGNALED(status) */ 49 #include <errno.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 NO_HISTORY 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 MKINIT 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(union node *); 97 STATIC void evalfor(union node *); 98 STATIC void evalcase(union node *, int); 99 STATIC void evalsubshell(union node *, int); 100 STATIC void expredir(union node *); 101 STATIC void evalpipe(union node *); 102 STATIC void evalcommand(union node *, int, struct backcmd *); 103 STATIC void prehash(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 command. 128 */ 129 130 int 131 evalcmd(int argc, char **argv) 132 { 133 char *p; 134 char *concat; 135 char **ap; 136 137 if (argc > 1) { 138 p = argv[1]; 139 if (argc > 2) { 140 STARTSTACKSTR(concat); 141 ap = argv + 2; 142 for (;;) { 143 while (*p) 144 STPUTC(*p++, concat); 145 if ((p = *ap++) == NULL) 146 break; 147 STPUTC(' ', concat); 148 } 149 STPUTC('\0', concat); 150 p = grabstackstr(concat); 151 } 152 evalstring(p); 153 } 154 return exitstatus; 155 } 156 157 158 /* 159 * Execute a command or commands contained in a string. 160 */ 161 162 void 163 evalstring(char *s) 164 { 165 union node *n; 166 struct stackmark smark; 167 168 setstackmark(&smark); 169 setinputstring(s, 1); 170 while ((n = parsecmd(0)) != NEOF) { 171 evaltree(n, 0); 172 popstackmark(&smark); 173 } 174 popfile(); 175 popstackmark(&smark); 176 } 177 178 179 180 /* 181 * Evaluate a parse tree. The value is left in the global variable 182 * exitstatus. 183 */ 184 185 void 186 evaltree(union node *n, int flags) 187 { 188 if (n == NULL) { 189 TRACE(("evaltree(NULL) called\n")); 190 exitstatus = 0; 191 goto out; 192 } 193 #ifndef NO_HISTORY 194 displayhist = 1; /* show history substitutions done with fc */ 195 #endif 196 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type)); 197 switch (n->type) { 198 case NSEMI: 199 evaltree(n->nbinary.ch1, 0); 200 if (evalskip) 201 goto out; 202 evaltree(n->nbinary.ch2, flags); 203 break; 204 case NAND: 205 evaltree(n->nbinary.ch1, EV_TESTED); 206 if (evalskip || exitstatus != 0) { 207 flags |= EV_TESTED; 208 goto out; 209 } 210 evaltree(n->nbinary.ch2, flags); 211 break; 212 case NOR: 213 evaltree(n->nbinary.ch1, EV_TESTED); 214 if (evalskip || exitstatus == 0) 215 goto out; 216 evaltree(n->nbinary.ch2, flags); 217 break; 218 case NREDIR: 219 expredir(n->nredir.redirect); 220 redirect(n->nredir.redirect, REDIR_PUSH); 221 evaltree(n->nredir.n, flags); 222 popredir(); 223 break; 224 case NSUBSHELL: 225 evalsubshell(n, flags); 226 break; 227 case NBACKGND: 228 evalsubshell(n, flags); 229 break; 230 case NIF: { 231 evaltree(n->nif.test, EV_TESTED); 232 if (evalskip) 233 goto out; 234 if (exitstatus == 0) 235 evaltree(n->nif.ifpart, flags); 236 else if (n->nif.elsepart) 237 evaltree(n->nif.elsepart, flags); 238 else 239 exitstatus = 0; 240 break; 241 } 242 case NWHILE: 243 case NUNTIL: 244 evalloop(n); 245 break; 246 case NFOR: 247 evalfor(n); 248 /* 249 * The 'for' command does not set exitstatus, so the value 250 * now in exitstatus is from the last command executed in 251 * the 'for' loop. That exit value had been tested (wrt 252 * 'sh -e' checking) while processing that command, and 253 * it should not be re-tested here. 254 */ 255 flags |= EV_TESTED; 256 break; 257 case NCASE: 258 evalcase(n, flags); 259 /* 260 * The 'case' command does not set exitstatus, so the value 261 * now in exitstatus is from the last command executed in 262 * the 'case' block. That exit value had been tested (wrt 263 * 'sh -e' checking) while processing that command, and 264 * it should not be re-tested here. 265 */ 266 flags |= EV_TESTED; 267 break; 268 case NDEFUN: 269 defun(n->narg.text, n->narg.next); 270 exitstatus = 0; 271 break; 272 case NNOT: 273 evaltree(n->nnot.com, EV_TESTED); 274 exitstatus = !exitstatus; 275 break; 276 277 case NPIPE: 278 evalpipe(n); 279 break; 280 case NCMD: 281 evalcommand(n, flags, (struct backcmd *)NULL); 282 break; 283 default: 284 out1fmt("Node type = %d\n", n->type); 285 flushout(&output); 286 break; 287 } 288 out: 289 if (pendingsigs) 290 dotrap(); 291 /* 292 * XXX - Like "!(n->type == NSEMI)", more types will probably 293 * need to be excluded from this test. It's probably better 294 * to set or unset EV_TESTED in the loop above than to bloat 295 * the conditional here. 296 */ 297 if ((flags & EV_EXIT) || (eflag && exitstatus 298 && !(flags & EV_TESTED) && !(n->type == NSEMI))) 299 exitshell(exitstatus); 300 } 301 302 303 STATIC void 304 evalloop(union node *n) 305 { 306 int status; 307 308 loopnest++; 309 status = 0; 310 for (;;) { 311 evaltree(n->nbinary.ch1, EV_TESTED); 312 if (evalskip) { 313 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 314 evalskip = 0; 315 continue; 316 } 317 if (evalskip == SKIPBREAK && --skipcount <= 0) 318 evalskip = 0; 319 break; 320 } 321 if (n->type == NWHILE) { 322 if (exitstatus != 0) 323 break; 324 } else { 325 if (exitstatus == 0) 326 break; 327 } 328 evaltree(n->nbinary.ch2, 0); 329 status = exitstatus; 330 if (evalskip) 331 goto skipping; 332 } 333 loopnest--; 334 exitstatus = status; 335 } 336 337 338 339 STATIC void 340 evalfor(union node *n) 341 { 342 struct arglist arglist; 343 union node *argp; 344 struct strlist *sp; 345 struct stackmark smark; 346 347 setstackmark(&smark); 348 arglist.lastp = &arglist.list; 349 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 350 oexitstatus = exitstatus; 351 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 352 if (evalskip) 353 goto out; 354 } 355 *arglist.lastp = NULL; 356 357 exitstatus = 0; 358 loopnest++; 359 for (sp = arglist.list ; sp ; sp = sp->next) { 360 setvar(n->nfor.var, sp->text, 0); 361 evaltree(n->nfor.body, 0); 362 if (evalskip) { 363 if (evalskip == SKIPCONT && --skipcount <= 0) { 364 evalskip = 0; 365 continue; 366 } 367 if (evalskip == SKIPBREAK && --skipcount <= 0) 368 evalskip = 0; 369 break; 370 } 371 } 372 loopnest--; 373 out: 374 popstackmark(&smark); 375 } 376 377 378 379 STATIC void 380 evalcase(union node *n, int flags) 381 { 382 union node *cp; 383 union node *patp; 384 struct arglist arglist; 385 struct stackmark smark; 386 387 setstackmark(&smark); 388 arglist.lastp = &arglist.list; 389 oexitstatus = exitstatus; 390 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 391 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 392 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 393 if (casematch(patp, arglist.list->text)) { 394 if (evalskip == 0) { 395 evaltree(cp->nclist.body, flags); 396 } 397 goto out; 398 } 399 } 400 } 401 out: 402 popstackmark(&smark); 403 } 404 405 406 407 /* 408 * Kick off a subshell to evaluate a tree. 409 */ 410 411 STATIC void 412 evalsubshell(union node *n, int flags) 413 { 414 struct job *jp; 415 int backgnd = (n->type == NBACKGND); 416 417 expredir(n->nredir.redirect); 418 jp = makejob(n, 1); 419 if (forkshell(jp, n, backgnd) == 0) { 420 if (backgnd) 421 flags &=~ EV_TESTED; 422 redirect(n->nredir.redirect, 0); 423 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 424 } 425 if (! backgnd) { 426 INTOFF; 427 exitstatus = waitforjob(jp, (int *)NULL); 428 INTON; 429 } 430 } 431 432 433 434 /* 435 * Compute the names of the files in a redirection list. 436 */ 437 438 STATIC void 439 expredir(union node *n) 440 { 441 union node *redir; 442 443 for (redir = n ; redir ; redir = redir->nfile.next) { 444 struct arglist fn; 445 fn.lastp = &fn.list; 446 oexitstatus = exitstatus; 447 switch (redir->type) { 448 case NFROM: 449 case NTO: 450 case NFROMTO: 451 case NAPPEND: 452 case NCLOBBER: 453 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 454 redir->nfile.expfname = fn.list->text; 455 break; 456 case NFROMFD: 457 case NTOFD: 458 if (redir->ndup.vname) { 459 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 460 fixredir(redir, fn.list->text, 1); 461 } 462 break; 463 } 464 } 465 } 466 467 468 469 /* 470 * Evaluate a pipeline. All the processes in the pipeline are children 471 * of the process creating the pipeline. (This differs from some versions 472 * of the shell, which make the last process in a pipeline the parent 473 * of all the rest.) 474 */ 475 476 STATIC void 477 evalpipe(union node *n) 478 { 479 struct job *jp; 480 struct nodelist *lp; 481 int pipelen; 482 int prevfd; 483 int pip[2]; 484 485 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 486 pipelen = 0; 487 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 488 pipelen++; 489 INTOFF; 490 jp = makejob(n, pipelen); 491 prevfd = -1; 492 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 493 prehash(lp->n); 494 pip[1] = -1; 495 if (lp->next) { 496 if (pipe(pip) < 0) { 497 close(prevfd); 498 error("Pipe call failed: %s", strerror(errno)); 499 } 500 } 501 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 502 INTON; 503 if (prevfd > 0) { 504 close(0); 505 copyfd(prevfd, 0); 506 close(prevfd); 507 } 508 if (pip[1] >= 0) { 509 if (!(prevfd >= 0 && pip[0] == 0)) 510 close(pip[0]); 511 if (pip[1] != 1) { 512 close(1); 513 copyfd(pip[1], 1); 514 close(pip[1]); 515 } 516 } 517 evaltree(lp->n, EV_EXIT); 518 } 519 if (prevfd >= 0) 520 close(prevfd); 521 prevfd = pip[0]; 522 close(pip[1]); 523 } 524 INTON; 525 if (n->npipe.backgnd == 0) { 526 INTOFF; 527 exitstatus = waitforjob(jp, (int *)NULL); 528 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 529 INTON; 530 } 531 } 532 533 534 535 /* 536 * Execute a command inside back quotes. If it's a builtin command, we 537 * want to save its output in a block obtained from malloc. Otherwise 538 * we fork off a subprocess and get the output of the command via a pipe. 539 * Should be called with interrupts off. 540 */ 541 542 void 543 evalbackcmd(union node *n, struct backcmd *result) 544 { 545 int pip[2]; 546 struct job *jp; 547 struct stackmark smark; /* unnecessary */ 548 549 setstackmark(&smark); 550 result->fd = -1; 551 result->buf = NULL; 552 result->nleft = 0; 553 result->jp = NULL; 554 if (n == NULL) { 555 exitstatus = 0; 556 goto out; 557 } 558 if (n->type == NCMD) { 559 exitstatus = oexitstatus; 560 evalcommand(n, EV_BACKCMD, result); 561 } else { 562 exitstatus = 0; 563 if (pipe(pip) < 0) 564 error("Pipe call failed: %s", strerror(errno)); 565 jp = makejob(n, 1); 566 if (forkshell(jp, n, FORK_NOJOB) == 0) { 567 FORCEINTON; 568 close(pip[0]); 569 if (pip[1] != 1) { 570 close(1); 571 copyfd(pip[1], 1); 572 close(pip[1]); 573 } 574 evaltree(n, EV_EXIT); 575 } 576 close(pip[1]); 577 result->fd = pip[0]; 578 result->jp = jp; 579 } 580 out: 581 popstackmark(&smark); 582 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 583 result->fd, result->buf, result->nleft, result->jp)); 584 } 585 586 587 588 /* 589 * Execute a simple command. 590 */ 591 592 STATIC void 593 evalcommand(union node *cmd, int flags, 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 || (cmdentry.cmdtype == CMDBUILTIN && 753 cmdentry.u.index == COMMANDCMD)) { 754 jp = makejob(cmd, 1); 755 mode = cmd->ncmd.backgnd; 756 if (flags & EV_BACKCMD) { 757 mode = FORK_NOJOB; 758 if (pipe(pip) < 0) 759 error("Pipe call failed: %s", strerror(errno)); 760 } 761 if (forkshell(jp, cmd, mode) != 0) 762 goto parent; /* at end of routine */ 763 if (flags & EV_BACKCMD) { 764 FORCEINTON; 765 close(pip[0]); 766 if (pip[1] != 1) { 767 close(1); 768 copyfd(pip[1], 1); 769 close(pip[1]); 770 } 771 } 772 flags |= EV_EXIT; 773 } 774 775 /* This is the child process if a fork occurred. */ 776 /* Execute the command. */ 777 if (cmdentry.cmdtype == CMDFUNCTION) { 778 #ifdef DEBUG 779 trputs("Shell function: "); trargs(argv); 780 #endif 781 redirect(cmd->ncmd.redirect, REDIR_PUSH); 782 saveparam = shellparam; 783 shellparam.malloc = 0; 784 shellparam.reset = 1; 785 shellparam.nparam = argc - 1; 786 shellparam.p = argv + 1; 787 shellparam.optnext = NULL; 788 INTOFF; 789 savelocalvars = localvars; 790 localvars = NULL; 791 INTON; 792 if (setjmp(jmploc.loc)) { 793 if (exception == EXSHELLPROC) 794 freeparam((struct shparam *)&saveparam); 795 else { 796 freeparam(&shellparam); 797 shellparam = saveparam; 798 } 799 poplocalvars(); 800 localvars = savelocalvars; 801 handler = savehandler; 802 longjmp(handler->loc, 1); 803 } 804 savehandler = handler; 805 handler = &jmploc; 806 for (sp = varlist.list ; sp ; sp = sp->next) 807 mklocal(sp->text); 808 funcnest++; 809 if (flags & EV_TESTED) 810 evaltree(cmdentry.u.func, EV_TESTED); 811 else 812 evaltree(cmdentry.u.func, 0); 813 funcnest--; 814 INTOFF; 815 poplocalvars(); 816 localvars = savelocalvars; 817 freeparam(&shellparam); 818 shellparam = saveparam; 819 handler = savehandler; 820 popredir(); 821 INTON; 822 if (evalskip == SKIPFUNC) { 823 evalskip = 0; 824 skipcount = 0; 825 } 826 if (flags & EV_EXIT) 827 exitshell(exitstatus); 828 } else if (cmdentry.cmdtype == CMDBUILTIN) { 829 #ifdef DEBUG 830 trputs("builtin command: "); trargs(argv); 831 #endif 832 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 833 if (flags == EV_BACKCMD) { 834 memout.nleft = 0; 835 memout.nextc = memout.buf; 836 memout.bufsize = 64; 837 mode |= REDIR_BACKQ; 838 } 839 redirect(cmd->ncmd.redirect, mode); 840 savecmdname = commandname; 841 cmdenviron = varlist.list; 842 e = -1; 843 if (setjmp(jmploc.loc)) { 844 e = exception; 845 exitstatus = (e == EXINT)? SIGINT+128 : 2; 846 goto cmddone; 847 } 848 savehandler = handler; 849 handler = &jmploc; 850 commandname = argv[0]; 851 argptr = argv + 1; 852 optptr = NULL; /* initialize nextopt */ 853 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 854 flushall(); 855 cmddone: 856 cmdenviron = NULL; 857 out1 = &output; 858 out2 = &errout; 859 freestdout(); 860 if (e != EXSHELLPROC) { 861 commandname = savecmdname; 862 if (flags & EV_EXIT) { 863 exitshell(exitstatus); 864 } 865 } 866 handler = savehandler; 867 if (e != -1) { 868 if ((e != EXERROR && e != EXEXEC) 869 || cmdentry.u.index == BLTINCMD 870 || cmdentry.u.index == DOTCMD 871 || cmdentry.u.index == EVALCMD 872 #ifndef NO_HISTORY 873 || cmdentry.u.index == HISTCMD 874 #endif 875 || cmdentry.u.index == EXECCMD 876 || cmdentry.u.index == COMMANDCMD) 877 exraise(e); 878 FORCEINTON; 879 } 880 if (cmdentry.u.index != EXECCMD) 881 popredir(); 882 if (flags == EV_BACKCMD) { 883 backcmd->buf = memout.buf; 884 backcmd->nleft = memout.nextc - memout.buf; 885 memout.buf = NULL; 886 } 887 } else { 888 #ifdef DEBUG 889 trputs("normal command: "); trargs(argv); 890 #endif 891 clearredir(); 892 redirect(cmd->ncmd.redirect, 0); 893 for (sp = varlist.list ; sp ; sp = sp->next) 894 setvareq(sp->text, VEXPORT|VSTACK); 895 envp = environment(); 896 shellexec(argv, envp, pathval(), cmdentry.u.index); 897 /*NOTREACHED*/ 898 } 899 goto out; 900 901 parent: /* parent process gets here (if we forked) */ 902 if (mode == 0) { /* argument to fork */ 903 INTOFF; 904 exitstatus = waitforjob(jp, &realstatus); 905 INTON; 906 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 907 evalskip = SKIPBREAK; 908 skipcount = loopnest; 909 } 910 } else if (mode == 2) { 911 backcmd->fd = pip[0]; 912 close(pip[1]); 913 backcmd->jp = jp; 914 } 915 916 out: 917 if (lastarg) 918 setvar("_", lastarg, 0); 919 if (do_clearcmdentry) 920 clearcmdentry(0); 921 popstackmark(&smark); 922 } 923 924 925 926 /* 927 * Search for a command. This is called before we fork so that the 928 * location of the command will be available in the parent as well as 929 * the child. The check for "goodname" is an overly conservative 930 * check that the name will not be subject to expansion. 931 */ 932 933 STATIC void 934 prehash(union node *n) 935 { 936 struct cmdentry entry; 937 938 if (n->type == NCMD && n->ncmd.args) 939 if (goodname(n->ncmd.args->narg.text)) 940 find_command(n->ncmd.args->narg.text, &entry, 0, 941 pathval()); 942 } 943 944 945 946 /* 947 * Builtin commands. Builtin commands whose functions are closely 948 * tied to evaluation are implemented here. 949 */ 950 951 /* 952 * No command given, or a bltin command with no arguments. Set the 953 * specified variables. 954 */ 955 956 int 957 bltincmd(int argc __unused, 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(int argc, 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 * The `command' command. 995 */ 996 int 997 commandcmd(int argc, char **argv) 998 { 999 static char stdpath[] = _PATH_STDPATH; 1000 struct jmploc loc, *old; 1001 struct strlist *sp; 1002 char *path; 1003 int ch; 1004 1005 for (sp = cmdenviron; sp ; sp = sp->next) 1006 setvareq(sp->text, VEXPORT|VSTACK); 1007 path = pathval(); 1008 1009 optind = optreset = 1; 1010 opterr = 0; 1011 while ((ch = getopt(argc, argv, "p")) != -1) { 1012 switch (ch) { 1013 case 'p': 1014 path = stdpath; 1015 break; 1016 case '?': 1017 default: 1018 error("unknown option: -%c", optopt); 1019 } 1020 } 1021 argc -= optind; 1022 argv += optind; 1023 1024 if (argc != 0) { 1025 old = handler; 1026 handler = &loc; 1027 if (setjmp(handler->loc) == 0) 1028 shellexec(argv, environment(), path, 0); 1029 handler = old; 1030 if (exception == EXEXEC) 1031 exit(exerrno); 1032 exraise(exception); 1033 } 1034 1035 /* 1036 * Do nothing successfully if no command was specified; 1037 * ksh also does this. 1038 */ 1039 exit(0); 1040 } 1041 1042 1043 /* 1044 * The return command. 1045 */ 1046 1047 int 1048 returncmd(int argc, char **argv) 1049 { 1050 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1051 1052 if (funcnest) { 1053 evalskip = SKIPFUNC; 1054 skipcount = 1; 1055 } else { 1056 /* skip the rest of the file */ 1057 evalskip = SKIPFILE; 1058 skipcount = 1; 1059 } 1060 return ret; 1061 } 1062 1063 1064 int 1065 falsecmd(int argc __unused, char **argv __unused) 1066 { 1067 return 1; 1068 } 1069 1070 1071 int 1072 truecmd(int argc __unused, char **argv __unused) 1073 { 1074 return 0; 1075 } 1076 1077 1078 int 1079 execcmd(int argc, char **argv) 1080 { 1081 if (argc > 1) { 1082 struct strlist *sp; 1083 1084 iflag = 0; /* exit on error */ 1085 mflag = 0; 1086 optschanged(); 1087 for (sp = cmdenviron; sp ; sp = sp->next) 1088 setvareq(sp->text, VEXPORT|VSTACK); 1089 shellexec(argv + 1, environment(), pathval(), 0); 1090 1091 } 1092 return 0; 1093 } 1094