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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #ifndef lint 34 #if 0 35 static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 36 #endif 37 #endif /* not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include <paths.h> 42 #include <signal.h> 43 #include <stdlib.h> 44 #include <unistd.h> 45 #include <sys/wait.h> /* For WIFSIGNALED(status) */ 46 #include <errno.h> 47 48 /* 49 * Evaluate a command. 50 */ 51 52 #include "shell.h" 53 #include "nodes.h" 54 #include "syntax.h" 55 #include "expand.h" 56 #include "parser.h" 57 #include "jobs.h" 58 #include "eval.h" 59 #include "builtins.h" 60 #include "options.h" 61 #include "exec.h" 62 #include "redir.h" 63 #include "input.h" 64 #include "output.h" 65 #include "trap.h" 66 #include "var.h" 67 #include "memalloc.h" 68 #include "error.h" 69 #include "show.h" 70 #include "mystring.h" 71 #ifndef NO_HISTORY 72 #include "myhistedit.h" 73 #endif 74 75 76 /* flags in argument to evaltree */ 77 #define EV_EXIT 01 /* exit after evaluating tree */ 78 #define EV_TESTED 02 /* exit status is checked; ignore -e flag */ 79 #define EV_BACKCMD 04 /* command executing within back quotes */ 80 81 MKINIT int evalskip; /* set if we are skipping commands */ 82 STATIC int skipcount; /* number of levels to skip */ 83 MKINIT int loopnest; /* current loop nesting level */ 84 int funcnest; /* depth of function calls */ 85 86 87 char *commandname; 88 struct strlist *cmdenviron; 89 int exitstatus; /* exit status of last command */ 90 int oexitstatus; /* saved exit status */ 91 92 93 STATIC void evalloop(union node *); 94 STATIC void evalfor(union node *); 95 STATIC void evalcase(union node *, int); 96 STATIC void evalsubshell(union node *, int); 97 STATIC void expredir(union node *); 98 STATIC void evalpipe(union node *); 99 STATIC void evalcommand(union node *, int, struct backcmd *); 100 STATIC void prehash(union node *); 101 102 103 /* 104 * Called to reset things after an exception. 105 */ 106 107 #ifdef mkinit 108 INCLUDE "eval.h" 109 110 RESET { 111 evalskip = 0; 112 loopnest = 0; 113 funcnest = 0; 114 } 115 116 SHELLPROC { 117 exitstatus = 0; 118 } 119 #endif 120 121 122 123 /* 124 * The eval command. 125 */ 126 127 int 128 evalcmd(int argc, char **argv) 129 { 130 char *p; 131 char *concat; 132 char **ap; 133 134 if (argc > 1) { 135 p = argv[1]; 136 if (argc > 2) { 137 STARTSTACKSTR(concat); 138 ap = argv + 2; 139 for (;;) { 140 while (*p) 141 STPUTC(*p++, concat); 142 if ((p = *ap++) == NULL) 143 break; 144 STPUTC(' ', concat); 145 } 146 STPUTC('\0', concat); 147 p = grabstackstr(concat); 148 } 149 evalstring(p); 150 } 151 return exitstatus; 152 } 153 154 155 /* 156 * Execute a command or commands contained in a string. 157 */ 158 159 void 160 evalstring(char *s) 161 { 162 union node *n; 163 struct stackmark smark; 164 165 setstackmark(&smark); 166 setinputstring(s, 1); 167 while ((n = parsecmd(0)) != NEOF) { 168 evaltree(n, 0); 169 popstackmark(&smark); 170 } 171 popfile(); 172 popstackmark(&smark); 173 } 174 175 176 177 /* 178 * Evaluate a parse tree. The value is left in the global variable 179 * exitstatus. 180 */ 181 182 void 183 evaltree(union node *n, int flags) 184 { 185 if (n == NULL) { 186 TRACE(("evaltree(NULL) called\n")); 187 exitstatus = 0; 188 goto out; 189 } 190 #ifndef NO_HISTORY 191 displayhist = 1; /* show history substitutions done with fc */ 192 #endif 193 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type)); 194 switch (n->type) { 195 case NSEMI: 196 evaltree(n->nbinary.ch1, 0); 197 if (evalskip) 198 goto out; 199 evaltree(n->nbinary.ch2, flags); 200 break; 201 case NAND: 202 evaltree(n->nbinary.ch1, EV_TESTED); 203 if (evalskip || exitstatus != 0) { 204 goto out; 205 } 206 evaltree(n->nbinary.ch2, flags); 207 break; 208 case NOR: 209 evaltree(n->nbinary.ch1, EV_TESTED); 210 if (evalskip || exitstatus == 0) 211 goto out; 212 evaltree(n->nbinary.ch2, flags); 213 break; 214 case NREDIR: 215 expredir(n->nredir.redirect); 216 redirect(n->nredir.redirect, REDIR_PUSH); 217 evaltree(n->nredir.n, flags); 218 popredir(); 219 break; 220 case NSUBSHELL: 221 evalsubshell(n, flags); 222 break; 223 case NBACKGND: 224 evalsubshell(n, flags); 225 break; 226 case NIF: { 227 evaltree(n->nif.test, EV_TESTED); 228 if (evalskip) 229 goto out; 230 if (exitstatus == 0) 231 evaltree(n->nif.ifpart, flags); 232 else if (n->nif.elsepart) 233 evaltree(n->nif.elsepart, flags); 234 else 235 exitstatus = 0; 236 break; 237 } 238 case NWHILE: 239 case NUNTIL: 240 evalloop(n); 241 break; 242 case NFOR: 243 evalfor(n); 244 break; 245 case NCASE: 246 evalcase(n, flags); 247 break; 248 case NDEFUN: 249 defun(n->narg.text, n->narg.next); 250 exitstatus = 0; 251 break; 252 case NNOT: 253 evaltree(n->nnot.com, EV_TESTED); 254 exitstatus = !exitstatus; 255 break; 256 257 case NPIPE: 258 evalpipe(n); 259 break; 260 case NCMD: 261 evalcommand(n, flags, (struct backcmd *)NULL); 262 break; 263 default: 264 out1fmt("Node type = %d\n", n->type); 265 flushout(&output); 266 break; 267 } 268 out: 269 if (pendingsigs) 270 dotrap(); 271 if ((flags & EV_EXIT) || (eflag && exitstatus 272 && !(flags & EV_TESTED) && (n->type == NCMD || 273 n->type == NSUBSHELL))) 274 exitshell(exitstatus); 275 } 276 277 278 STATIC void 279 evalloop(union node *n) 280 { 281 int status; 282 283 loopnest++; 284 status = 0; 285 for (;;) { 286 evaltree(n->nbinary.ch1, EV_TESTED); 287 if (evalskip) { 288 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 289 evalskip = 0; 290 continue; 291 } 292 if (evalskip == SKIPBREAK && --skipcount <= 0) 293 evalskip = 0; 294 break; 295 } 296 if (n->type == NWHILE) { 297 if (exitstatus != 0) 298 break; 299 } else { 300 if (exitstatus == 0) 301 break; 302 } 303 evaltree(n->nbinary.ch2, 0); 304 status = exitstatus; 305 if (evalskip) 306 goto skipping; 307 } 308 loopnest--; 309 exitstatus = status; 310 } 311 312 313 314 STATIC void 315 evalfor(union node *n) 316 { 317 struct arglist arglist; 318 union node *argp; 319 struct strlist *sp; 320 struct stackmark smark; 321 322 setstackmark(&smark); 323 arglist.lastp = &arglist.list; 324 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 325 oexitstatus = exitstatus; 326 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 327 if (evalskip) 328 goto out; 329 } 330 *arglist.lastp = NULL; 331 332 exitstatus = 0; 333 loopnest++; 334 for (sp = arglist.list ; sp ; sp = sp->next) { 335 setvar(n->nfor.var, sp->text, 0); 336 evaltree(n->nfor.body, 0); 337 if (evalskip) { 338 if (evalskip == SKIPCONT && --skipcount <= 0) { 339 evalskip = 0; 340 continue; 341 } 342 if (evalskip == SKIPBREAK && --skipcount <= 0) 343 evalskip = 0; 344 break; 345 } 346 } 347 loopnest--; 348 out: 349 popstackmark(&smark); 350 } 351 352 353 354 STATIC void 355 evalcase(union node *n, int flags) 356 { 357 union node *cp; 358 union node *patp; 359 struct arglist arglist; 360 struct stackmark smark; 361 362 setstackmark(&smark); 363 arglist.lastp = &arglist.list; 364 oexitstatus = exitstatus; 365 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 366 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 367 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 368 if (casematch(patp, arglist.list->text)) { 369 if (evalskip == 0) { 370 evaltree(cp->nclist.body, flags); 371 } 372 goto out; 373 } 374 } 375 } 376 out: 377 popstackmark(&smark); 378 } 379 380 381 382 /* 383 * Kick off a subshell to evaluate a tree. 384 */ 385 386 STATIC void 387 evalsubshell(union node *n, int flags) 388 { 389 struct job *jp; 390 int backgnd = (n->type == NBACKGND); 391 392 expredir(n->nredir.redirect); 393 jp = makejob(n, 1); 394 if (forkshell(jp, n, backgnd) == 0) { 395 if (backgnd) 396 flags &=~ EV_TESTED; 397 redirect(n->nredir.redirect, 0); 398 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 399 } 400 if (! backgnd) { 401 INTOFF; 402 exitstatus = waitforjob(jp, (int *)NULL); 403 INTON; 404 } 405 } 406 407 408 409 /* 410 * Compute the names of the files in a redirection list. 411 */ 412 413 STATIC void 414 expredir(union node *n) 415 { 416 union node *redir; 417 418 for (redir = n ; redir ; redir = redir->nfile.next) { 419 struct arglist fn; 420 fn.lastp = &fn.list; 421 oexitstatus = exitstatus; 422 switch (redir->type) { 423 case NFROM: 424 case NTO: 425 case NFROMTO: 426 case NAPPEND: 427 case NCLOBBER: 428 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 429 redir->nfile.expfname = fn.list->text; 430 break; 431 case NFROMFD: 432 case NTOFD: 433 if (redir->ndup.vname) { 434 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 435 fixredir(redir, fn.list->text, 1); 436 } 437 break; 438 } 439 } 440 } 441 442 443 444 /* 445 * Evaluate a pipeline. All the processes in the pipeline are children 446 * of the process creating the pipeline. (This differs from some versions 447 * of the shell, which make the last process in a pipeline the parent 448 * of all the rest.) 449 */ 450 451 STATIC void 452 evalpipe(union node *n) 453 { 454 struct job *jp; 455 struct nodelist *lp; 456 int pipelen; 457 int prevfd; 458 int pip[2]; 459 460 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 461 pipelen = 0; 462 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 463 pipelen++; 464 INTOFF; 465 jp = makejob(n, pipelen); 466 prevfd = -1; 467 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 468 prehash(lp->n); 469 pip[1] = -1; 470 if (lp->next) { 471 if (pipe(pip) < 0) { 472 close(prevfd); 473 error("Pipe call failed: %s", strerror(errno)); 474 } 475 } 476 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 477 INTON; 478 if (prevfd > 0) { 479 dup2(prevfd, 0); 480 close(prevfd); 481 } 482 if (pip[1] >= 0) { 483 if (!(prevfd >= 0 && pip[0] == 0)) 484 close(pip[0]); 485 if (pip[1] != 1) { 486 dup2(pip[1], 1); 487 close(pip[1]); 488 } 489 } 490 evaltree(lp->n, EV_EXIT); 491 } 492 if (prevfd >= 0) 493 close(prevfd); 494 prevfd = pip[0]; 495 close(pip[1]); 496 } 497 INTON; 498 if (n->npipe.backgnd == 0) { 499 INTOFF; 500 exitstatus = waitforjob(jp, (int *)NULL); 501 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 502 INTON; 503 } 504 } 505 506 507 508 /* 509 * Execute a command inside back quotes. If it's a builtin command, we 510 * want to save its output in a block obtained from malloc. Otherwise 511 * we fork off a subprocess and get the output of the command via a pipe. 512 * Should be called with interrupts off. 513 */ 514 515 void 516 evalbackcmd(union node *n, struct backcmd *result) 517 { 518 int pip[2]; 519 struct job *jp; 520 struct stackmark smark; /* unnecessary */ 521 522 setstackmark(&smark); 523 result->fd = -1; 524 result->buf = NULL; 525 result->nleft = 0; 526 result->jp = NULL; 527 if (n == NULL) { 528 exitstatus = 0; 529 goto out; 530 } 531 if (n->type == NCMD) { 532 exitstatus = oexitstatus; 533 evalcommand(n, EV_BACKCMD, result); 534 } else { 535 exitstatus = 0; 536 if (pipe(pip) < 0) 537 error("Pipe call failed: %s", strerror(errno)); 538 jp = makejob(n, 1); 539 if (forkshell(jp, n, FORK_NOJOB) == 0) { 540 FORCEINTON; 541 close(pip[0]); 542 if (pip[1] != 1) { 543 dup2(pip[1], 1); 544 close(pip[1]); 545 } 546 evaltree(n, EV_EXIT); 547 } 548 close(pip[1]); 549 result->fd = pip[0]; 550 result->jp = jp; 551 } 552 out: 553 popstackmark(&smark); 554 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 555 result->fd, result->buf, result->nleft, result->jp)); 556 } 557 558 559 560 /* 561 * Execute a simple command. 562 */ 563 564 STATIC void 565 evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 566 { 567 struct stackmark smark; 568 union node *argp; 569 struct arglist arglist; 570 struct arglist varlist; 571 char **argv; 572 int argc; 573 char **envp; 574 int varflag; 575 struct strlist *sp; 576 int mode; 577 int pip[2]; 578 struct cmdentry cmdentry; 579 struct job *jp; 580 struct jmploc jmploc; 581 struct jmploc *volatile savehandler; 582 char *volatile savecmdname; 583 volatile struct shparam saveparam; 584 struct localvar *volatile savelocalvars; 585 volatile int e; 586 char *lastarg; 587 int realstatus; 588 int do_clearcmdentry; 589 #if __GNUC__ 590 /* Avoid longjmp clobbering */ 591 (void) &argv; 592 (void) &argc; 593 (void) &lastarg; 594 (void) &flags; 595 (void) &do_clearcmdentry; 596 #endif 597 598 /* First expand the arguments. */ 599 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 600 setstackmark(&smark); 601 arglist.lastp = &arglist.list; 602 varlist.lastp = &varlist.list; 603 varflag = 1; 604 do_clearcmdentry = 0; 605 oexitstatus = exitstatus; 606 exitstatus = 0; 607 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 608 char *p = argp->narg.text; 609 if (varflag && is_name(*p)) { 610 do { 611 p++; 612 } while (is_in_name(*p)); 613 if (*p == '=') { 614 expandarg(argp, &varlist, EXP_VARTILDE); 615 continue; 616 } 617 } 618 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 619 varflag = 0; 620 } 621 *arglist.lastp = NULL; 622 *varlist.lastp = NULL; 623 expredir(cmd->ncmd.redirect); 624 argc = 0; 625 for (sp = arglist.list ; sp ; sp = sp->next) 626 argc++; 627 argv = stalloc(sizeof (char *) * (argc + 1)); 628 629 for (sp = arglist.list ; sp ; sp = sp->next) { 630 TRACE(("evalcommand arg: %s\n", sp->text)); 631 *argv++ = sp->text; 632 } 633 *argv = NULL; 634 lastarg = NULL; 635 if (iflag && funcnest == 0 && argc > 0) 636 lastarg = argv[-1]; 637 argv -= argc; 638 639 /* Print the command if xflag is set. */ 640 if (xflag) { 641 outc('+', &errout); 642 for (sp = varlist.list ; sp ; sp = sp->next) { 643 outc(' ', &errout); 644 out2str(sp->text); 645 } 646 for (sp = arglist.list ; sp ; sp = sp->next) { 647 outc(' ', &errout); 648 out2str(sp->text); 649 } 650 outc('\n', &errout); 651 flushout(&errout); 652 } 653 654 /* Now locate the command. */ 655 if (argc == 0) { 656 cmdentry.cmdtype = CMDBUILTIN; 657 cmdentry.u.index = BLTINCMD; 658 } else { 659 static const char PATH[] = "PATH="; 660 char *path = pathval(); 661 662 /* 663 * Modify the command lookup path, if a PATH= assignment 664 * is present 665 */ 666 for (sp = varlist.list ; sp ; sp = sp->next) 667 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 668 path = sp->text + sizeof(PATH) - 1; 669 /* 670 * On `PATH=... command`, we need to make 671 * sure that the command isn't using the 672 * non-updated hash table of the outer PATH 673 * setting and we need to make sure that 674 * the hash table isn't filled with items 675 * from the temporary setting. 676 * 677 * It would be better to forbit using and 678 * updating the table while this command 679 * runs, by the command finding mechanism 680 * is heavily integrated with hash handling, 681 * so we just delete the hash before and after 682 * the command runs. Partly deleting like 683 * changepatch() does doesn't seem worth the 684 * bookinging effort, since most such runs add 685 * directories in front of the new PATH. 686 */ 687 clearcmdentry(0); 688 do_clearcmdentry = 1; 689 } 690 691 find_command(argv[0], &cmdentry, 1, path); 692 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 693 exitstatus = 127; 694 flushout(&errout); 695 return; 696 } 697 /* implement the bltin builtin here */ 698 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 699 for (;;) { 700 argv++; 701 if (--argc == 0) 702 break; 703 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 704 outfmt(&errout, "%s: not found\n", *argv); 705 exitstatus = 127; 706 flushout(&errout); 707 return; 708 } 709 if (cmdentry.u.index != BLTINCMD) 710 break; 711 } 712 } 713 } 714 715 /* Fork off a child process if necessary. */ 716 if (cmd->ncmd.backgnd 717 || (cmdentry.cmdtype == CMDNORMAL 718 && ((flags & EV_EXIT) == 0 || Tflag)) 719 || ((flags & EV_BACKCMD) != 0 720 && (cmdentry.cmdtype != CMDBUILTIN 721 || cmdentry.u.index == CDCMD 722 || cmdentry.u.index == DOTCMD 723 || cmdentry.u.index == EVALCMD)) 724 || (cmdentry.cmdtype == CMDBUILTIN && 725 cmdentry.u.index == COMMANDCMD)) { 726 jp = makejob(cmd, 1); 727 mode = cmd->ncmd.backgnd; 728 if (flags & EV_BACKCMD) { 729 mode = FORK_NOJOB; 730 if (pipe(pip) < 0) 731 error("Pipe call failed: %s", strerror(errno)); 732 } 733 if (forkshell(jp, cmd, mode) != 0) 734 goto parent; /* at end of routine */ 735 if (flags & EV_BACKCMD) { 736 FORCEINTON; 737 close(pip[0]); 738 if (pip[1] != 1) { 739 dup2(pip[1], 1); 740 close(pip[1]); 741 } 742 } 743 flags |= EV_EXIT; 744 } 745 746 /* This is the child process if a fork occurred. */ 747 /* Execute the command. */ 748 if (cmdentry.cmdtype == CMDFUNCTION) { 749 #ifdef DEBUG 750 trputs("Shell function: "); trargs(argv); 751 #endif 752 redirect(cmd->ncmd.redirect, REDIR_PUSH); 753 saveparam = shellparam; 754 shellparam.malloc = 0; 755 shellparam.reset = 1; 756 shellparam.nparam = argc - 1; 757 shellparam.p = argv + 1; 758 shellparam.optnext = NULL; 759 INTOFF; 760 savelocalvars = localvars; 761 localvars = NULL; 762 INTON; 763 if (setjmp(jmploc.loc)) { 764 if (exception == EXSHELLPROC) 765 freeparam((struct shparam *)&saveparam); 766 else { 767 freeparam(&shellparam); 768 shellparam = saveparam; 769 } 770 poplocalvars(); 771 localvars = savelocalvars; 772 handler = savehandler; 773 longjmp(handler->loc, 1); 774 } 775 savehandler = handler; 776 handler = &jmploc; 777 for (sp = varlist.list ; sp ; sp = sp->next) 778 mklocal(sp->text); 779 funcnest++; 780 if (flags & EV_TESTED) 781 evaltree(cmdentry.u.func, EV_TESTED); 782 else 783 evaltree(cmdentry.u.func, 0); 784 funcnest--; 785 INTOFF; 786 poplocalvars(); 787 localvars = savelocalvars; 788 freeparam(&shellparam); 789 shellparam = saveparam; 790 handler = savehandler; 791 popredir(); 792 INTON; 793 if (evalskip == SKIPFUNC) { 794 evalskip = 0; 795 skipcount = 0; 796 } 797 if (flags & EV_EXIT) 798 exitshell(exitstatus); 799 } else if (cmdentry.cmdtype == CMDBUILTIN) { 800 #ifdef DEBUG 801 trputs("builtin command: "); trargs(argv); 802 #endif 803 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 804 if (flags == EV_BACKCMD) { 805 memout.nleft = 0; 806 memout.nextc = memout.buf; 807 memout.bufsize = 64; 808 mode |= REDIR_BACKQ; 809 } 810 redirect(cmd->ncmd.redirect, mode); 811 savecmdname = commandname; 812 cmdenviron = varlist.list; 813 e = -1; 814 if (setjmp(jmploc.loc)) { 815 e = exception; 816 exitstatus = (e == EXINT)? SIGINT+128 : 2; 817 goto cmddone; 818 } 819 savehandler = handler; 820 handler = &jmploc; 821 commandname = argv[0]; 822 argptr = argv + 1; 823 optptr = NULL; /* initialize nextopt */ 824 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 825 flushall(); 826 cmddone: 827 cmdenviron = NULL; 828 out1 = &output; 829 out2 = &errout; 830 freestdout(); 831 if (e != EXSHELLPROC) { 832 commandname = savecmdname; 833 if (flags & EV_EXIT) { 834 exitshell(exitstatus); 835 } 836 } 837 handler = savehandler; 838 if (e != -1) { 839 if ((e != EXERROR && e != EXEXEC) 840 || cmdentry.u.index == BLTINCMD 841 || cmdentry.u.index == DOTCMD 842 || cmdentry.u.index == EVALCMD 843 #ifndef NO_HISTORY 844 || cmdentry.u.index == HISTCMD 845 #endif 846 || cmdentry.u.index == EXECCMD 847 || cmdentry.u.index == COMMANDCMD) 848 exraise(e); 849 FORCEINTON; 850 } 851 if (cmdentry.u.index != EXECCMD) 852 popredir(); 853 if (flags == EV_BACKCMD) { 854 backcmd->buf = memout.buf; 855 backcmd->nleft = memout.nextc - memout.buf; 856 memout.buf = NULL; 857 } 858 } else { 859 #ifdef DEBUG 860 trputs("normal command: "); trargs(argv); 861 #endif 862 clearredir(); 863 redirect(cmd->ncmd.redirect, 0); 864 for (sp = varlist.list ; sp ; sp = sp->next) 865 setvareq(sp->text, VEXPORT|VSTACK); 866 envp = environment(); 867 shellexec(argv, envp, pathval(), cmdentry.u.index); 868 /*NOTREACHED*/ 869 } 870 goto out; 871 872 parent: /* parent process gets here (if we forked) */ 873 if (mode == 0) { /* argument to fork */ 874 INTOFF; 875 exitstatus = waitforjob(jp, &realstatus); 876 INTON; 877 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 878 evalskip = SKIPBREAK; 879 skipcount = loopnest; 880 } 881 } else if (mode == 2) { 882 backcmd->fd = pip[0]; 883 close(pip[1]); 884 backcmd->jp = jp; 885 } 886 887 out: 888 if (lastarg) 889 setvar("_", lastarg, 0); 890 if (do_clearcmdentry) 891 clearcmdentry(0); 892 popstackmark(&smark); 893 } 894 895 896 897 /* 898 * Search for a command. This is called before we fork so that the 899 * location of the command will be available in the parent as well as 900 * the child. The check for "goodname" is an overly conservative 901 * check that the name will not be subject to expansion. 902 */ 903 904 STATIC void 905 prehash(union node *n) 906 { 907 struct cmdentry entry; 908 909 if (n->type == NCMD && n->ncmd.args) 910 if (goodname(n->ncmd.args->narg.text)) 911 find_command(n->ncmd.args->narg.text, &entry, 0, 912 pathval()); 913 } 914 915 916 917 /* 918 * Builtin commands. Builtin commands whose functions are closely 919 * tied to evaluation are implemented here. 920 */ 921 922 /* 923 * No command given, or a bltin command with no arguments. Set the 924 * specified variables. 925 */ 926 927 int 928 bltincmd(int argc __unused, char **argv __unused) 929 { 930 listsetvar(cmdenviron); 931 /* 932 * Preserve exitstatus of a previous possible redirection 933 * as POSIX mandates 934 */ 935 return exitstatus; 936 } 937 938 939 /* 940 * Handle break and continue commands. Break, continue, and return are 941 * all handled by setting the evalskip flag. The evaluation routines 942 * above all check this flag, and if it is set they start skipping 943 * commands rather than executing them. The variable skipcount is 944 * the number of loops to break/continue, or the number of function 945 * levels to return. (The latter is always 1.) It should probably 946 * be an error to break out of more loops than exist, but it isn't 947 * in the standard shell so we don't make it one here. 948 */ 949 950 int 951 breakcmd(int argc, char **argv) 952 { 953 int n = argc > 1 ? number(argv[1]) : 1; 954 955 if (n > loopnest) 956 n = loopnest; 957 if (n > 0) { 958 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 959 skipcount = n; 960 } 961 return 0; 962 } 963 964 /* 965 * The `command' command. 966 */ 967 int 968 commandcmd(int argc, char **argv) 969 { 970 static char stdpath[] = _PATH_STDPATH; 971 struct jmploc loc, *old; 972 struct strlist *sp; 973 char *path; 974 int ch; 975 976 for (sp = cmdenviron; sp ; sp = sp->next) 977 setvareq(sp->text, VEXPORT|VSTACK); 978 path = pathval(); 979 980 optind = optreset = 1; 981 opterr = 0; 982 while ((ch = getopt(argc, argv, "p")) != -1) { 983 switch (ch) { 984 case 'p': 985 path = stdpath; 986 break; 987 case '?': 988 default: 989 error("unknown option: -%c", optopt); 990 } 991 } 992 argc -= optind; 993 argv += optind; 994 995 if (argc != 0) { 996 old = handler; 997 handler = &loc; 998 if (setjmp(handler->loc) == 0) 999 shellexec(argv, environment(), path, 0); 1000 handler = old; 1001 if (exception == EXEXEC) 1002 exit(exerrno); 1003 exraise(exception); 1004 } 1005 1006 /* 1007 * Do nothing successfully if no command was specified; 1008 * ksh also does this. 1009 */ 1010 exit(0); 1011 } 1012 1013 1014 /* 1015 * The return command. 1016 */ 1017 1018 int 1019 returncmd(int argc, 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(int argc __unused, char **argv __unused) 1037 { 1038 return 1; 1039 } 1040 1041 1042 int 1043 truecmd(int argc __unused, char **argv __unused) 1044 { 1045 return 0; 1046 } 1047 1048 1049 int 1050 execcmd(int argc, char **argv) 1051 { 1052 if (argc > 1) { 1053 struct strlist *sp; 1054 1055 iflag = 0; /* exit on error */ 1056 mflag = 0; 1057 optschanged(); 1058 for (sp = cmdenviron; sp ; sp = sp->next) 1059 setvareq(sp->text, VEXPORT|VSTACK); 1060 shellexec(argv + 1, environment(), pathval(), 0); 1061 1062 } 1063 return 0; 1064 } 1065