eval.c revision 1.22
1 /* $NetBSD: eval.c,v 1.22 1995/05/14 04:19:18 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Kenneth Almquist. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #ifndef lint 40 #if 0 41 static char sccsid[] = "@(#)eval.c 8.6 (Berkeley) 5/14/95"; 42 #else 43 static char rcsid[] = "$NetBSD: eval.c,v 1.22 1995/05/14 04:19:18 christos Exp $"; 44 #endif 45 #endif /* not lint */ 46 47 #include <signal.h> 48 #include <unistd.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 84 /* reasons for skipping commands (see comment on breakcmd routine) */ 85 #define SKIPBREAK 1 86 #define SKIPCONT 2 87 #define SKIPFUNC 3 88 89 MKINIT int evalskip; /* set if we are skipping commands */ 90 STATIC int skipcount; /* number of levels to skip */ 91 MKINIT int loopnest; /* current loop nesting level */ 92 int funcnest; /* depth of function calls */ 93 94 95 char *commandname; 96 struct strlist *cmdenviron; 97 int exitstatus; /* exit status of last command */ 98 99 100 STATIC void evalloop __P((union node *)); 101 STATIC void evalfor __P((union node *)); 102 STATIC void evalcase __P((union node *, int)); 103 STATIC void evalsubshell __P((union node *, int)); 104 STATIC void expredir __P((union node *)); 105 STATIC void evalpipe __P((union node *)); 106 STATIC void evalcommand __P((union node *, int, struct backcmd *)); 107 STATIC void prehash __P((union node *)); 108 109 110 /* 111 * Called to reset things after an exception. 112 */ 113 114 #ifdef mkinit 115 INCLUDE "eval.h" 116 117 RESET { 118 evalskip = 0; 119 loopnest = 0; 120 funcnest = 0; 121 } 122 123 SHELLPROC { 124 exitstatus = 0; 125 } 126 #endif 127 128 129 130 /* 131 * The eval commmand. 132 */ 133 134 int 135 evalcmd(argc, argv) 136 int argc; 137 char **argv; 138 { 139 char *p; 140 char *concat; 141 char **ap; 142 143 if (argc > 1) { 144 p = argv[1]; 145 if (argc > 2) { 146 STARTSTACKSTR(concat); 147 ap = argv + 2; 148 for (;;) { 149 while (*p) 150 STPUTC(*p++, concat); 151 if ((p = *ap++) == NULL) 152 break; 153 STPUTC(' ', concat); 154 } 155 STPUTC('\0', concat); 156 p = grabstackstr(concat); 157 } 158 evalstring(p); 159 } 160 return exitstatus; 161 } 162 163 164 /* 165 * Execute a command or commands contained in a string. 166 */ 167 168 void 169 evalstring(s) 170 char *s; 171 { 172 union node *n; 173 struct stackmark smark; 174 175 setstackmark(&smark); 176 setinputstring(s, 1); 177 while ((n = parsecmd(0)) != NEOF) { 178 evaltree(n, 0); 179 popstackmark(&smark); 180 } 181 popfile(); 182 popstackmark(&smark); 183 } 184 185 186 187 /* 188 * Evaluate a parse tree. The value is left in the global variable 189 * exitstatus. 190 */ 191 192 void 193 evaltree(n, flags) 194 union node *n; 195 int flags; 196 { 197 if (n == NULL) { 198 TRACE(("evaltree(NULL) called\n")); 199 exitstatus = 0; 200 goto out; 201 } 202 #ifndef NO_HISTORY 203 displayhist = 1; /* show history substitutions done with fc */ 204 #endif 205 TRACE(("evaltree(0x%lx: %d) called\n", (long)n, n->type)); 206 switch (n->type) { 207 case NSEMI: 208 evaltree(n->nbinary.ch1, 0); 209 if (evalskip) 210 goto out; 211 evaltree(n->nbinary.ch2, flags); 212 break; 213 case NAND: 214 evaltree(n->nbinary.ch1, EV_TESTED); 215 if (evalskip || exitstatus != 0) 216 goto out; 217 evaltree(n->nbinary.ch2, flags); 218 break; 219 case NOR: 220 evaltree(n->nbinary.ch1, EV_TESTED); 221 if (evalskip || exitstatus == 0) 222 goto out; 223 evaltree(n->nbinary.ch2, flags); 224 break; 225 case NREDIR: 226 expredir(n->nredir.redirect); 227 redirect(n->nredir.redirect, REDIR_PUSH); 228 evaltree(n->nredir.n, flags); 229 popredir(); 230 break; 231 case NSUBSHELL: 232 evalsubshell(n, flags); 233 break; 234 case NBACKGND: 235 evalsubshell(n, flags); 236 break; 237 case NIF: { 238 int status; 239 240 evaltree(n->nif.test, EV_TESTED); 241 status = exitstatus; 242 exitstatus = 0; 243 if (evalskip) 244 goto out; 245 if (status == 0) 246 evaltree(n->nif.ifpart, flags); 247 else if (n->nif.elsepart) 248 evaltree(n->nif.elsepart, flags); 249 break; 250 } 251 case NWHILE: 252 case NUNTIL: 253 evalloop(n); 254 break; 255 case NFOR: 256 evalfor(n); 257 break; 258 case NCASE: 259 evalcase(n, flags); 260 break; 261 case NDEFUN: 262 defun(n->narg.text, n->narg.next); 263 exitstatus = 0; 264 break; 265 case NNOT: 266 evaltree(n->nnot.com, EV_TESTED); 267 exitstatus = !exitstatus; 268 break; 269 270 case NPIPE: 271 evalpipe(n); 272 break; 273 case NCMD: 274 evalcommand(n, flags, (struct backcmd *)NULL); 275 break; 276 default: 277 out1fmt("Node type = %d\n", n->type); 278 flushout(&output); 279 break; 280 } 281 out: 282 if (pendingsigs) 283 dotrap(); 284 if ((flags & EV_EXIT) || (eflag && exitstatus && !(flags & EV_TESTED))) 285 exitshell(exitstatus); 286 } 287 288 289 STATIC void 290 evalloop(n) 291 union node *n; 292 { 293 int status; 294 295 loopnest++; 296 status = 0; 297 for (;;) { 298 evaltree(n->nbinary.ch1, EV_TESTED); 299 if (evalskip) { 300 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 301 evalskip = 0; 302 continue; 303 } 304 if (evalskip == SKIPBREAK && --skipcount <= 0) 305 evalskip = 0; 306 break; 307 } 308 if (n->type == NWHILE) { 309 if (exitstatus != 0) 310 break; 311 } else { 312 if (exitstatus == 0) 313 break; 314 } 315 evaltree(n->nbinary.ch2, 0); 316 status = exitstatus; 317 if (evalskip) 318 goto skipping; 319 } 320 loopnest--; 321 exitstatus = status; 322 } 323 324 325 326 STATIC void 327 evalfor(n) 328 union node *n; 329 { 330 struct arglist arglist; 331 union node *argp; 332 struct strlist *sp; 333 struct stackmark smark; 334 335 setstackmark(&smark); 336 arglist.lastp = &arglist.list; 337 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 338 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 339 if (evalskip) 340 goto out; 341 } 342 *arglist.lastp = NULL; 343 344 exitstatus = 0; 345 loopnest++; 346 for (sp = arglist.list ; sp ; sp = sp->next) { 347 setvar(n->nfor.var, sp->text, 0); 348 evaltree(n->nfor.body, 0); 349 if (evalskip) { 350 if (evalskip == SKIPCONT && --skipcount <= 0) { 351 evalskip = 0; 352 continue; 353 } 354 if (evalskip == SKIPBREAK && --skipcount <= 0) 355 evalskip = 0; 356 break; 357 } 358 } 359 loopnest--; 360 out: 361 popstackmark(&smark); 362 } 363 364 365 366 STATIC void 367 evalcase(n, flags) 368 union node *n; 369 int flags; 370 { 371 union node *cp; 372 union node *patp; 373 struct arglist arglist; 374 struct stackmark smark; 375 376 setstackmark(&smark); 377 arglist.lastp = &arglist.list; 378 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 379 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 380 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 381 if (casematch(patp, arglist.list->text)) { 382 if (evalskip == 0) { 383 evaltree(cp->nclist.body, flags); 384 } 385 goto out; 386 } 387 } 388 } 389 out: 390 popstackmark(&smark); 391 } 392 393 394 395 /* 396 * Kick off a subshell to evaluate a tree. 397 */ 398 399 STATIC void 400 evalsubshell(n, flags) 401 union node *n; 402 int flags; 403 { 404 struct job *jp; 405 int backgnd = (n->type == NBACKGND); 406 407 expredir(n->nredir.redirect); 408 jp = makejob(n, 1); 409 if (forkshell(jp, n, backgnd) == 0) { 410 if (backgnd) 411 flags &=~ EV_TESTED; 412 redirect(n->nredir.redirect, 0); 413 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 414 } 415 if (! backgnd) { 416 INTOFF; 417 exitstatus = waitforjob(jp); 418 INTON; 419 } 420 } 421 422 423 424 /* 425 * Compute the names of the files in a redirection list. 426 */ 427 428 STATIC void 429 expredir(n) 430 union node *n; 431 { 432 register union node *redir; 433 434 for (redir = n ; redir ; redir = redir->nfile.next) { 435 struct arglist fn; 436 fn.lastp = &fn.list; 437 switch (redir->type) { 438 case NFROM: 439 case NTO: 440 case NAPPEND: 441 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 442 redir->nfile.expfname = fn.list->text; 443 break; 444 case NFROMFD: 445 case NTOFD: 446 if (redir->ndup.vname) { 447 expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE); 448 fixredir(redir, fn.list->text, 1); 449 } 450 break; 451 } 452 } 453 } 454 455 456 457 /* 458 * Evaluate a pipeline. All the processes in the pipeline are children 459 * of the process creating the pipeline. (This differs from some versions 460 * of the shell, which make the last process in a pipeline the parent 461 * of all the rest.) 462 */ 463 464 STATIC void 465 evalpipe(n) 466 union node *n; 467 { 468 struct job *jp; 469 struct nodelist *lp; 470 int pipelen; 471 int prevfd; 472 int pip[2]; 473 474 TRACE(("evalpipe(0x%lx) called\n", (long)n)); 475 pipelen = 0; 476 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 477 pipelen++; 478 INTOFF; 479 jp = makejob(n, pipelen); 480 prevfd = -1; 481 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 482 prehash(lp->n); 483 pip[1] = -1; 484 if (lp->next) { 485 if (pipe(pip) < 0) { 486 close(prevfd); 487 error("Pipe call failed"); 488 } 489 } 490 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 491 INTON; 492 if (prevfd > 0) { 493 close(0); 494 copyfd(prevfd, 0); 495 close(prevfd); 496 } 497 if (pip[1] >= 0) { 498 close(pip[0]); 499 if (pip[1] != 1) { 500 close(1); 501 copyfd(pip[1], 1); 502 close(pip[1]); 503 } 504 } 505 evaltree(lp->n, EV_EXIT); 506 } 507 if (prevfd >= 0) 508 close(prevfd); 509 prevfd = pip[0]; 510 close(pip[1]); 511 } 512 INTON; 513 if (n->npipe.backgnd == 0) { 514 INTOFF; 515 exitstatus = waitforjob(jp); 516 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 517 INTON; 518 } 519 } 520 521 522 523 /* 524 * Execute a command inside back quotes. If it's a builtin command, we 525 * want to save its output in a block obtained from malloc. Otherwise 526 * we fork off a subprocess and get the output of the command via a pipe. 527 * Should be called with interrupts off. 528 */ 529 530 void 531 evalbackcmd(n, result) 532 union node *n; 533 struct backcmd *result; 534 { 535 int pip[2]; 536 struct job *jp; 537 struct stackmark smark; /* unnecessary */ 538 539 setstackmark(&smark); 540 result->fd = -1; 541 result->buf = NULL; 542 result->nleft = 0; 543 result->jp = NULL; 544 exitstatus = 0; 545 if (n == NULL) 546 goto out; 547 if (n->type == NCMD) { 548 evalcommand(n, EV_BACKCMD, result); 549 } else { 550 if (pipe(pip) < 0) 551 error("Pipe call failed"); 552 jp = makejob(n, 1); 553 if (forkshell(jp, n, FORK_NOJOB) == 0) { 554 FORCEINTON; 555 close(pip[0]); 556 if (pip[1] != 1) { 557 close(1); 558 copyfd(pip[1], 1); 559 close(pip[1]); 560 } 561 evaltree(n, EV_EXIT); 562 } 563 close(pip[1]); 564 result->fd = pip[0]; 565 result->jp = jp; 566 } 567 out: 568 popstackmark(&smark); 569 TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n", 570 result->fd, result->buf, result->nleft, result->jp)); 571 } 572 573 574 575 /* 576 * Execute a simple command. 577 */ 578 579 STATIC void 580 evalcommand(cmd, flags, backcmd) 581 union node *cmd; 582 int flags; 583 struct backcmd *backcmd; 584 { 585 struct stackmark smark; 586 union node *argp; 587 struct arglist arglist; 588 struct arglist varlist; 589 char **argv; 590 int argc; 591 char **envp; 592 int varflag; 593 struct strlist *sp; 594 int mode; 595 int pip[2]; 596 struct cmdentry cmdentry; 597 struct job *jp; 598 struct jmploc jmploc; 599 struct jmploc *volatile savehandler; 600 char *volatile savecmdname; 601 volatile struct shparam saveparam; 602 struct localvar *volatile savelocalvars; 603 volatile int e; 604 char *lastarg; 605 #if __GNUC__ 606 /* Avoid longjmp clobbering */ 607 (void) &argv; 608 (void) &argc; 609 (void) &lastarg; 610 (void) &flags; 611 #endif 612 613 /* First expand the arguments. */ 614 TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags)); 615 setstackmark(&smark); 616 arglist.lastp = &arglist.list; 617 varlist.lastp = &varlist.list; 618 varflag = 1; 619 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 620 char *p = argp->narg.text; 621 if (varflag && is_name(*p)) { 622 do { 623 p++; 624 } while (is_in_name(*p)); 625 if (*p == '=') { 626 expandarg(argp, &varlist, EXP_VARTILDE); 627 continue; 628 } 629 } 630 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 631 varflag = 0; 632 } 633 *arglist.lastp = NULL; 634 *varlist.lastp = NULL; 635 expredir(cmd->ncmd.redirect); 636 argc = 0; 637 for (sp = arglist.list ; sp ; sp = sp->next) 638 argc++; 639 argv = stalloc(sizeof (char *) * (argc + 1)); 640 641 for (sp = arglist.list ; sp ; sp = sp->next) { 642 TRACE(("evalcommand arg: %s\n", sp->text)); 643 *argv++ = sp->text; 644 } 645 *argv = NULL; 646 lastarg = NULL; 647 if (iflag && funcnest == 0 && argc > 0) 648 lastarg = argv[-1]; 649 argv -= argc; 650 651 /* Print the command if xflag is set. */ 652 if (xflag) { 653 outc('+', &errout); 654 for (sp = varlist.list ; sp ; sp = sp->next) { 655 outc(' ', &errout); 656 out2str(sp->text); 657 } 658 for (sp = arglist.list ; sp ; sp = sp->next) { 659 outc(' ', &errout); 660 out2str(sp->text); 661 } 662 outc('\n', &errout); 663 flushout(&errout); 664 } 665 666 /* Now locate the command. */ 667 if (argc == 0) { 668 cmdentry.cmdtype = CMDBUILTIN; 669 cmdentry.u.index = BLTINCMD; 670 } else { 671 find_command(argv[0], &cmdentry, 1); 672 if (cmdentry.cmdtype == CMDUNKNOWN) { /* command not found */ 673 exitstatus = 2; 674 flushout(&errout); 675 return; 676 } 677 /* implement the bltin builtin here */ 678 if (cmdentry.cmdtype == CMDBUILTIN && cmdentry.u.index == BLTINCMD) { 679 for (;;) { 680 argv++; 681 if (--argc == 0) 682 break; 683 if ((cmdentry.u.index = find_builtin(*argv)) < 0) { 684 outfmt(&errout, "%s: not found\n", *argv); 685 exitstatus = 2; 686 flushout(&errout); 687 return; 688 } 689 if (cmdentry.u.index != BLTINCMD) 690 break; 691 } 692 } 693 } 694 695 /* Fork off a child process if necessary. */ 696 if (cmd->ncmd.backgnd 697 || (cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0) 698 || ((flags & EV_BACKCMD) != 0 699 && (cmdentry.cmdtype != CMDBUILTIN 700 || cmdentry.u.index == DOTCMD 701 || cmdentry.u.index == EVALCMD))) { 702 jp = makejob(cmd, 1); 703 mode = cmd->ncmd.backgnd; 704 if (flags & EV_BACKCMD) { 705 mode = FORK_NOJOB; 706 if (pipe(pip) < 0) 707 error("Pipe call failed"); 708 } 709 if (forkshell(jp, cmd, mode) != 0) 710 goto parent; /* at end of routine */ 711 if (flags & EV_BACKCMD) { 712 FORCEINTON; 713 close(pip[0]); 714 if (pip[1] != 1) { 715 close(1); 716 copyfd(pip[1], 1); 717 close(pip[1]); 718 } 719 } 720 flags |= EV_EXIT; 721 } 722 723 /* This is the child process if a fork occurred. */ 724 /* Execute the command. */ 725 if (cmdentry.cmdtype == CMDFUNCTION) { 726 trputs("Shell function: "); trargs(argv); 727 redirect(cmd->ncmd.redirect, REDIR_PUSH); 728 saveparam = shellparam; 729 shellparam.malloc = 0; 730 shellparam.nparam = argc - 1; 731 shellparam.p = argv + 1; 732 shellparam.optnext = NULL; 733 INTOFF; 734 savelocalvars = localvars; 735 localvars = NULL; 736 INTON; 737 if (setjmp(jmploc.loc)) { 738 if (exception == EXSHELLPROC) 739 freeparam((struct shparam *)&saveparam); 740 else { 741 freeparam(&shellparam); 742 shellparam = saveparam; 743 } 744 poplocalvars(); 745 localvars = savelocalvars; 746 handler = savehandler; 747 longjmp(handler->loc, 1); 748 } 749 savehandler = handler; 750 handler = &jmploc; 751 for (sp = varlist.list ; sp ; sp = sp->next) 752 mklocal(sp->text); 753 funcnest++; 754 evaltree(cmdentry.u.func, 0); 755 funcnest--; 756 INTOFF; 757 poplocalvars(); 758 localvars = savelocalvars; 759 freeparam(&shellparam); 760 shellparam = saveparam; 761 handler = savehandler; 762 popredir(); 763 INTON; 764 if (evalskip == SKIPFUNC) { 765 evalskip = 0; 766 skipcount = 0; 767 } 768 if (flags & EV_EXIT) 769 exitshell(exitstatus); 770 } else if (cmdentry.cmdtype == CMDBUILTIN) { 771 trputs("builtin command: "); trargs(argv); 772 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 773 if (flags == EV_BACKCMD) { 774 memout.nleft = 0; 775 memout.nextc = memout.buf; 776 memout.bufsize = 64; 777 mode |= REDIR_BACKQ; 778 } 779 redirect(cmd->ncmd.redirect, mode); 780 savecmdname = commandname; 781 cmdenviron = varlist.list; 782 e = -1; 783 if (setjmp(jmploc.loc)) { 784 e = exception; 785 exitstatus = (e == EXINT)? SIGINT+128 : 2; 786 goto cmddone; 787 } 788 savehandler = handler; 789 handler = &jmploc; 790 commandname = argv[0]; 791 argptr = argv + 1; 792 optptr = NULL; /* initialize nextopt */ 793 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 794 flushall(); 795 cmddone: 796 out1 = &output; 797 out2 = &errout; 798 freestdout(); 799 if (e != EXSHELLPROC) { 800 commandname = savecmdname; 801 if (flags & EV_EXIT) { 802 exitshell(exitstatus); 803 } 804 } 805 handler = savehandler; 806 if (e != -1) { 807 if (e != EXERROR || cmdentry.u.index == BLTINCMD 808 || cmdentry.u.index == DOTCMD 809 || cmdentry.u.index == EVALCMD 810 #ifndef NO_HISTORY 811 || cmdentry.u.index == HISTCMD 812 #endif 813 || cmdentry.u.index == EXECCMD) 814 exraise(e); 815 FORCEINTON; 816 } 817 if (cmdentry.u.index != EXECCMD) 818 popredir(); 819 if (flags == EV_BACKCMD) { 820 backcmd->buf = memout.buf; 821 backcmd->nleft = memout.nextc - memout.buf; 822 memout.buf = NULL; 823 } 824 } else { 825 trputs("normal command: "); trargs(argv); 826 clearredir(); 827 redirect(cmd->ncmd.redirect, 0); 828 for (sp = varlist.list ; sp ; sp = sp->next) 829 setvareq(sp->text, VEXPORT|VSTACK); 830 envp = environment(); 831 shellexec(argv, envp, pathval(), cmdentry.u.index); 832 /*NOTREACHED*/ 833 } 834 goto out; 835 836 parent: /* parent process gets here (if we forked) */ 837 if (mode == 0) { /* argument to fork */ 838 INTOFF; 839 exitstatus = waitforjob(jp); 840 INTON; 841 } else if (mode == 2) { 842 backcmd->fd = pip[0]; 843 close(pip[1]); 844 backcmd->jp = jp; 845 } 846 847 out: 848 if (lastarg) 849 setvar("_", lastarg, 0); 850 popstackmark(&smark); 851 } 852 853 854 855 /* 856 * Search for a command. This is called before we fork so that the 857 * location of the command will be available in the parent as well as 858 * the child. The check for "goodname" is an overly conservative 859 * check that the name will not be subject to expansion. 860 */ 861 862 STATIC void 863 prehash(n) 864 union node *n; 865 { 866 struct cmdentry entry; 867 868 if (n->type == NCMD && n->ncmd.args) 869 if (goodname(n->ncmd.args->narg.text)) 870 find_command(n->ncmd.args->narg.text, &entry, 0); 871 } 872 873 874 875 /* 876 * Builtin commands. Builtin commands whose functions are closely 877 * tied to evaluation are implemented here. 878 */ 879 880 /* 881 * No command given, or a bltin command with no arguments. Set the 882 * specified variables. 883 */ 884 885 int 886 bltincmd(argc, argv) 887 int argc; 888 char **argv; 889 { 890 listsetvar(cmdenviron); 891 /* 892 * Preserve exitstatus of a previous possible redirection 893 * as POSIX mandates 894 */ 895 return exitstatus; 896 } 897 898 899 /* 900 * Handle break and continue commands. Break, continue, and return are 901 * all handled by setting the evalskip flag. The evaluation routines 902 * above all check this flag, and if it is set they start skipping 903 * commands rather than executing them. The variable skipcount is 904 * the number of loops to break/continue, or the number of function 905 * levels to return. (The latter is always 1.) It should probably 906 * be an error to break out of more loops than exist, but it isn't 907 * in the standard shell so we don't make it one here. 908 */ 909 910 int 911 breakcmd(argc, argv) 912 int argc; 913 char **argv; 914 { 915 int n; 916 917 n = 1; 918 if (argc > 1) 919 n = number(argv[1]); 920 if (n > loopnest) 921 n = loopnest; 922 if (n > 0) { 923 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 924 skipcount = n; 925 } 926 return 0; 927 } 928 929 930 /* 931 * The return command. 932 */ 933 934 int 935 returncmd(argc, argv) 936 int argc; 937 char **argv; 938 { 939 int ret; 940 941 ret = exitstatus; 942 if (argc > 1) 943 ret = number(argv[1]); 944 if (funcnest) { 945 evalskip = SKIPFUNC; 946 skipcount = 1; 947 } 948 return ret; 949 } 950 951 952 int 953 falsecmd(argc, argv) 954 int argc; 955 char **argv; 956 { 957 return 1; 958 } 959 960 961 int 962 truecmd(argc, argv) 963 int argc; 964 char **argv; 965 { 966 return 0; 967 } 968 969 970 int 971 execcmd(argc, argv) 972 int argc; 973 char **argv; 974 { 975 if (argc > 1) { 976 struct strlist *sp; 977 978 iflag = 0; /* exit on error */ 979 mflag = 0; 980 optschanged(); 981 for (sp = cmdenviron; sp ; sp = sp->next) 982 setvareq(sp->text, VEXPORT|VSTACK); 983 shellexec(argv + 1, environment(), pathval(), 0); 984 985 } 986 return 0; 987 } 988
Indexes created Mon Sep 22 13:09:51 GMT 2025