eval.c revision 53891
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 39static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 40#endif 41static const char rcsid[] = 42 "$FreeBSD: head/bin/sh/eval.c 53891 1999-11-29 19:11:01Z cracauer $"; 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 83MKINIT int evalskip; /* set if we are skipping commands */ 84STATIC int skipcount; /* number of levels to skip */ 85MKINIT int loopnest; /* current loop nesting level */ 86int funcnest; /* depth of function calls */ 87 88 89char *commandname; 90struct strlist *cmdenviron; 91int exitstatus; /* exit status of last command */ 92int oexitstatus; /* saved exit status */ 93 94 95STATIC void evalloop __P((union node *)); 96STATIC void evalfor __P((union node *)); 97STATIC void evalcase __P((union node *, int)); 98STATIC void evalsubshell __P((union node *, int)); 99STATIC void expredir __P((union node *)); 100STATIC void evalpipe __P((union node *)); 101STATIC void evalcommand __P((union node *, int, struct backcmd *)); 102STATIC void prehash __P((union node *)); 103 104 105/* 106 * Called to reset things after an exception. 107 */ 108 109#ifdef mkinit 110INCLUDE "eval.h" 111 112RESET { 113 evalskip = 0; 114 loopnest = 0; 115 funcnest = 0; 116} 117 118SHELLPROC { 119 exitstatus = 0; 120} 121#endif 122 123 124 125/* 126 * The eval command. 127 */ 128 129int 130evalcmd(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 163void 164evalstring(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 187void 188evaltree(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 } 276out: 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 291STATIC void 292evalloop(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) { 302skipping: 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 328STATIC void 329evalfor(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--; 363out: 364 popstackmark(&smark); 365} 366 367 368 369STATIC void 370evalcase(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 } 393out: 394 popstackmark(&smark); 395} 396 397 398 399/* 400 * Kick off a subshell to evaluate a tree. 401 */ 402 403STATIC void 404evalsubshell(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 432STATIC void 433expredir(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 469STATIC void 470evalpipe(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 536void 537evalbackcmd(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 } 576out: 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 588STATIC void 589evalcommand(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#if __GNUC__ 616 /* Avoid longjmp clobbering */ 617 (void) &argv; 618 (void) &argc; 619 (void) &lastarg; 620 (void) &flags; 621#endif 622 623 /* First expand the arguments. */ 624 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 625 setstackmark(&smark); 626 arglist.lastp = &arglist.list; 627 varlist.lastp = &varlist.list; 628 varflag = 1; 629 oexitstatus = exitstatus; 630 exitstatus = 0; 631 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 632 char *p = argp->narg.text; 633 if (varflag && is_name(*p)) { 634 do { 635 p++; 636 } while (is_in_name(*p)); 637 if (*p == '=') { 638 expandarg(argp, &varlist, EXP_VARTILDE); 639 continue; 640 } 641 } 642 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 643 varflag = 0; 644 } 645 *arglist.lastp = NULL; 646 *varlist.lastp = NULL; 647 expredir(cmd->ncmd.redirect); 648 argc = 0; 649 for (sp = arglist.list ; sp ; sp = sp->next) 650 argc++; 651 argv = stalloc(sizeof (char *) * (argc + 1)); 652 653 for (sp = arglist.list ; sp ; sp = sp->next) { 654 TRACE(("evalcommand arg: %s\n", sp->text)); 655 *argv++ = sp->text; 656 } 657 *argv = NULL; 658 lastarg = NULL; 659 if (iflag && funcnest == 0 && argc > 0) 660 lastarg = argv[-1]; 661 argv -= argc; 662 663 /* Print the command if xflag is set. */ 664 if (xflag) { 665 outc('+', &errout); 666 for (sp = varlist.list ; sp ; sp = sp->next) { 667 outc(' ', &errout); 668 out2str(sp->text); 669 } 670 for (sp = arglist.list ; sp ; sp = sp->next) { 671 outc(' ', &errout); 672 out2str(sp->text); 673 } 674 outc('\n', &errout); 675 flushout(&errout); 676 } 677 678 /* Now locate the command. */ 679 if (argc == 0) { 680 cmdentry.cmdtype = CMDBUILTIN; 681 cmdentry.u.index = BLTINCMD; 682 } else { 683 static const char PATH[] = "PATH="; 684 char *path = pathval(); 685 686 /* 687 * Modify the command lookup path, if a PATH= assignment 688 * is present 689 */ 690 for (sp = varlist.list ; sp ; sp = sp->next) 691 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) 692 path = sp->text + sizeof(PATH) - 1; 693 694 find_command(argv[0], &cmdentry, 1, path); 695 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 696 exitstatus = 127; 697 flushout(&errout); 698 return; 699 } 700 /* implement the bltin builtin here */ 701 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 702 for (;;) { 703 argv++; 704 if (--argc == 0) 705 break; 706 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 707 outfmt(&errout, "%s: not found\n", *argv); 708 exitstatus = 127; 709 flushout(&errout); 710 return; 711 } 712 if (cmdentry.u.index != BLTINCMD) 713 break; 714 } 715 } 716 } 717 718 /* Fork off a child process if necessary. */ 719 if (cmd->ncmd.backgnd 720 || (cmdentry.cmdtype == CMDNORMAL 721 && ((flags & EV_EXIT) == 0 || Tflag)) 722 || ((flags & EV_BACKCMD) != 0 723 && (cmdentry.cmdtype != CMDBUILTIN 724 || cmdentry.u.index == CDCMD 725 || cmdentry.u.index == DOTCMD 726 || cmdentry.u.index == EVALCMD))) { 727 jp = makejob(cmd, 1); 728 mode = cmd->ncmd.backgnd; 729 if (flags & EV_BACKCMD) { 730 mode = FORK_NOJOB; 731 if (pipe(pip) < 0) 732 error("Pipe call failed: %s", strerror(errno)); 733 } 734 if (forkshell(jp, cmd, mode) != 0) 735 goto parent; /* at end of routine */ 736 if (flags & EV_BACKCMD) { 737 FORCEINTON; 738 close(pip[0]); 739 if (pip[1] != 1) { 740 close(1); 741 copyfd(pip[1], 1); 742 close(pip[1]); 743 } 744 } 745 flags |= EV_EXIT; 746 } 747 748 /* This is the child process if a fork occurred. */ 749 /* Execute the command. */ 750 if (cmdentry.cmdtype == CMDFUNCTION) { 751#ifdef DEBUG 752 trputs("Shell function: "); trargs(argv); 753#endif 754 redirect(cmd->ncmd.redirect, REDIR_PUSH); 755 saveparam = shellparam; 756 shellparam.malloc = 0; 757 shellparam.reset = 1; 758 shellparam.nparam = argc - 1; 759 shellparam.p = argv + 1; 760 shellparam.optnext = NULL; 761 INTOFF; 762 savelocalvars = localvars; 763 localvars = NULL; 764 INTON; 765 if (setjmp(jmploc.loc)) { 766 if (exception == EXSHELLPROC) 767 freeparam((struct shparam *)&saveparam); 768 else { 769 freeparam(&shellparam); 770 shellparam = saveparam; 771 } 772 poplocalvars(); 773 localvars = savelocalvars; 774 handler = savehandler; 775 longjmp(handler->loc, 1); 776 } 777 savehandler = handler; 778 handler = &jmploc; 779 for (sp = varlist.list ; sp ; sp = sp->next) 780 mklocal(sp->text); 781 funcnest++; 782 if (flags & EV_TESTED) 783 evaltree(cmdentry.u.func, EV_TESTED); 784 else 785 evaltree(cmdentry.u.func, 0); 786 funcnest--; 787 INTOFF; 788 poplocalvars(); 789 localvars = savelocalvars; 790 freeparam(&shellparam); 791 shellparam = saveparam; 792 handler = savehandler; 793 popredir(); 794 INTON; 795 if (evalskip == SKIPFUNC) { 796 evalskip = 0; 797 skipcount = 0; 798 } 799 if (flags & EV_EXIT) 800 exitshell(exitstatus); 801 } else if (cmdentry.cmdtype == CMDBUILTIN) { 802#ifdef DEBUG 803 trputs("builtin command: "); trargs(argv); 804#endif 805 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 806 if (flags == EV_BACKCMD) { 807 memout.nleft = 0; 808 memout.nextc = memout.buf; 809 memout.bufsize = 64; 810 mode |= REDIR_BACKQ; 811 } 812 redirect(cmd->ncmd.redirect, mode); 813 savecmdname = commandname; 814 cmdenviron = varlist.list; 815 e = -1; 816 if (setjmp(jmploc.loc)) { 817 e = exception; 818 exitstatus = (e == EXINT)? SIGINT+128 : 2; 819 goto cmddone; 820 } 821 savehandler = handler; 822 handler = &jmploc; 823 commandname = argv[0]; 824 argptr = argv + 1; 825 optptr = NULL; /* initialize nextopt */ 826 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 827 flushall(); 828cmddone: 829 out1 = &output; 830 out2 = &errout; 831 freestdout(); 832 if (e != EXSHELLPROC) { 833 commandname = savecmdname; 834 if (flags & EV_EXIT) { 835 exitshell(exitstatus); 836 } 837 } 838 handler = savehandler; 839 if (e != -1) { 840 if ((e != EXERROR && e != EXEXEC) 841 || cmdentry.u.index == BLTINCMD 842 || cmdentry.u.index == DOTCMD 843 || cmdentry.u.index == EVALCMD 844#ifndef NO_HISTORY 845 || cmdentry.u.index == HISTCMD 846#endif 847 || cmdentry.u.index == EXECCMD) 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 872parent: /* 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 887out: 888 if (lastarg) 889 setvar("_", lastarg, 0); 890 popstackmark(&smark); 891} 892 893 894 895/* 896 * Search for a command. This is called before we fork so that the 897 * location of the command will be available in the parent as well as 898 * the child. The check for "goodname" is an overly conservative 899 * check that the name will not be subject to expansion. 900 */ 901 902STATIC void 903prehash(n) 904 union node *n; 905{ 906 struct cmdentry entry; 907 908 if (n->type == NCMD && n->ncmd.args) 909 if (goodname(n->ncmd.args->narg.text)) 910 find_command(n->ncmd.args->narg.text, &entry, 0, 911 pathval()); 912} 913 914 915 916/* 917 * Builtin commands. Builtin commands whose functions are closely 918 * tied to evaluation are implemented here. 919 */ 920 921/* 922 * No command given, or a bltin command with no arguments. Set the 923 * specified variables. 924 */ 925 926int 927bltincmd(argc, argv) 928 int argc __unused; 929 char **argv __unused; 930{ 931 listsetvar(cmdenviron); 932 /* 933 * Preserve exitstatus of a previous possible redirection 934 * as POSIX mandates 935 */ 936 return exitstatus; 937} 938 939 940/* 941 * Handle break and continue commands. Break, continue, and return are 942 * all handled by setting the evalskip flag. The evaluation routines 943 * above all check this flag, and if it is set they start skipping 944 * commands rather than executing them. The variable skipcount is 945 * the number of loops to break/continue, or the number of function 946 * levels to return. (The latter is always 1.) It should probably 947 * be an error to break out of more loops than exist, but it isn't 948 * in the standard shell so we don't make it one here. 949 */ 950 951int 952breakcmd(argc, argv) 953 int argc; 954 char **argv; 955{ 956 int n = argc > 1 ? number(argv[1]) : 1; 957 958 if (n > loopnest) 959 n = loopnest; 960 if (n > 0) { 961 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 962 skipcount = n; 963 } 964 return 0; 965} 966 967 968/* 969 * The return command. 970 */ 971 972int 973returncmd(argc, argv) 974 int argc; 975 char **argv; 976{ 977 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 978 979 if (funcnest) { 980 evalskip = SKIPFUNC; 981 skipcount = 1; 982 } else { 983 /* skip the rest of the file */ 984 evalskip = SKIPFILE; 985 skipcount = 1; 986 } 987 return ret; 988} 989 990 991int 992falsecmd(argc, argv) 993 int argc __unused; 994 char **argv __unused; 995{ 996 return 1; 997} 998 999 1000int 1001truecmd(argc, argv) 1002 int argc __unused; 1003 char **argv __unused; 1004{ 1005 return 0; 1006} 1007 1008 1009int 1010execcmd(argc, argv) 1011 int argc; 1012 char **argv; 1013{ 1014 if (argc > 1) { 1015 struct strlist *sp; 1016 1017 iflag = 0; /* exit on error */ 1018 mflag = 0; 1019 optschanged(); 1020 for (sp = cmdenviron; sp ; sp = sp->next) 1021 setvareq(sp->text, VEXPORT|VSTACK); 1022 shellexec(argv + 1, environment(), pathval(), 0); 1023 1024 } 1025 return 0; 1026} 1027