eval.c revision 216761
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 35static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 36#endif 37#endif /* not lint */ 38#include <sys/cdefs.h> 39__FBSDID("$FreeBSD: head/bin/sh/eval.c 216761 2010-12-28 13:28:24Z jilles $"); 40 41#include <paths.h> 42#include <signal.h> 43#include <stdlib.h> 44#include <unistd.h> 45#include <sys/resource.h> 46#include <sys/wait.h> /* For WIFSIGNALED(status) */ 47#include <errno.h> 48 49/* 50 * Evaluate a command. 51 */ 52 53#include "shell.h" 54#include "nodes.h" 55#include "syntax.h" 56#include "expand.h" 57#include "parser.h" 58#include "jobs.h" 59#include "eval.h" 60#include "builtins.h" 61#include "options.h" 62#include "exec.h" 63#include "redir.h" 64#include "input.h" 65#include "output.h" 66#include "trap.h" 67#include "var.h" 68#include "memalloc.h" 69#include "error.h" 70#include "show.h" 71#include "mystring.h" 72#ifndef NO_HISTORY 73#include "myhistedit.h" 74#endif 75 76 77int evalskip; /* set if we are skipping commands */ 78static int skipcount; /* number of levels to skip */ 79MKINIT int loopnest; /* current loop nesting level */ 80int funcnest; /* depth of function calls */ 81static int builtin_flags; /* evalcommand flags for builtins */ 82 83 84char *commandname; 85struct strlist *cmdenviron; 86int exitstatus; /* exit status of last command */ 87int oexitstatus; /* saved exit status */ 88 89 90static void evalloop(union node *, int); 91static void evalfor(union node *, int); 92static void evalcase(union node *, int); 93static void evalsubshell(union node *, int); 94static void evalredir(union node *, int); 95static void expredir(union node *); 96static void evalpipe(union node *); 97static void evalcommand(union node *, int, struct backcmd *); 98static void prehash(union node *); 99 100 101/* 102 * Called to reset things after an exception. 103 */ 104 105#ifdef mkinit 106INCLUDE "eval.h" 107 108RESET { 109 evalskip = 0; 110 loopnest = 0; 111 funcnest = 0; 112} 113 114SHELLPROC { 115 exitstatus = 0; 116} 117#endif 118 119 120 121/* 122 * The eval command. 123 */ 124 125int 126evalcmd(int argc, char **argv) 127{ 128 char *p; 129 char *concat; 130 char **ap; 131 132 if (argc > 1) { 133 p = argv[1]; 134 if (argc > 2) { 135 STARTSTACKSTR(concat); 136 ap = argv + 2; 137 for (;;) { 138 STPUTS(p, concat); 139 if ((p = *ap++) == NULL) 140 break; 141 STPUTC(' ', concat); 142 } 143 STPUTC('\0', concat); 144 p = grabstackstr(concat); 145 } 146 evalstring(p, builtin_flags & EV_TESTED); 147 } else 148 exitstatus = 0; 149 return exitstatus; 150} 151 152 153/* 154 * Execute a command or commands contained in a string. 155 */ 156 157void 158evalstring(char *s, int flags) 159{ 160 union node *n; 161 struct stackmark smark; 162 int flags_exit; 163 int any; 164 165 flags_exit = flags & EV_EXIT; 166 flags &= ~EV_EXIT; 167 any = 0; 168 setstackmark(&smark); 169 setinputstring(s, 1); 170 while ((n = parsecmd(0)) != NEOF) { 171 if (n != NULL) { 172 if (flags_exit && preadateof()) 173 evaltree(n, flags | EV_EXIT); 174 else 175 evaltree(n, flags); 176 any = 1; 177 } 178 popstackmark(&smark); 179 } 180 popfile(); 181 popstackmark(&smark); 182 if (!any) 183 exitstatus = 0; 184 if (flags_exit) 185 exitshell(exitstatus); 186} 187 188 189/* 190 * Evaluate a parse tree. The value is left in the global variable 191 * exitstatus. 192 */ 193 194void 195evaltree(union node *n, int flags) 196{ 197 int do_etest; 198 union node *next; 199 200 do_etest = 0; 201 if (n == NULL) { 202 TRACE(("evaltree(NULL) called\n")); 203 exitstatus = 0; 204 goto out; 205 } 206 do { 207 next = NULL; 208#ifndef NO_HISTORY 209 displayhist = 1; /* show history substitutions done with fc */ 210#endif 211 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 212 switch (n->type) { 213 case NSEMI: 214 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 215 if (evalskip) 216 goto out; 217 next = n->nbinary.ch2; 218 break; 219 case NAND: 220 evaltree(n->nbinary.ch1, EV_TESTED); 221 if (evalskip || exitstatus != 0) { 222 goto out; 223 } 224 next = n->nbinary.ch2; 225 break; 226 case NOR: 227 evaltree(n->nbinary.ch1, EV_TESTED); 228 if (evalskip || exitstatus == 0) 229 goto out; 230 next = n->nbinary.ch2; 231 break; 232 case NREDIR: 233 evalredir(n, flags); 234 break; 235 case NSUBSHELL: 236 evalsubshell(n, flags); 237 do_etest = !(flags & EV_TESTED); 238 break; 239 case NBACKGND: 240 evalsubshell(n, flags); 241 break; 242 case NIF: { 243 evaltree(n->nif.test, EV_TESTED); 244 if (evalskip) 245 goto out; 246 if (exitstatus == 0) 247 next = n->nif.ifpart; 248 else if (n->nif.elsepart) 249 next = n->nif.elsepart; 250 else 251 exitstatus = 0; 252 break; 253 } 254 case NWHILE: 255 case NUNTIL: 256 evalloop(n, flags & ~EV_EXIT); 257 break; 258 case NFOR: 259 evalfor(n, flags & ~EV_EXIT); 260 break; 261 case NCASE: 262 evalcase(n, flags); 263 break; 264 case NDEFUN: 265 defun(n->narg.text, n->narg.next); 266 exitstatus = 0; 267 break; 268 case NNOT: 269 evaltree(n->nnot.com, EV_TESTED); 270 exitstatus = !exitstatus; 271 break; 272 273 case NPIPE: 274 evalpipe(n); 275 do_etest = !(flags & EV_TESTED); 276 break; 277 case NCMD: 278 evalcommand(n, flags, (struct backcmd *)NULL); 279 do_etest = !(flags & EV_TESTED); 280 break; 281 default: 282 out1fmt("Node type = %d\n", n->type); 283 flushout(&output); 284 break; 285 } 286 n = next; 287 } while (n != NULL); 288out: 289 if (pendingsigs) 290 dotrap(); 291 if ((flags & EV_EXIT) || (eflag && exitstatus != 0 && do_etest)) 292 exitshell(exitstatus); 293} 294 295 296static void 297evalloop(union node *n, int flags) 298{ 299 int status; 300 301 loopnest++; 302 status = 0; 303 for (;;) { 304 evaltree(n->nbinary.ch1, EV_TESTED); 305 if (evalskip) { 306skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 307 evalskip = 0; 308 continue; 309 } 310 if (evalskip == SKIPBREAK && --skipcount <= 0) 311 evalskip = 0; 312 if (evalskip == SKIPFUNC || evalskip == SKIPFILE) 313 status = exitstatus; 314 break; 315 } 316 if (n->type == NWHILE) { 317 if (exitstatus != 0) 318 break; 319 } else { 320 if (exitstatus == 0) 321 break; 322 } 323 evaltree(n->nbinary.ch2, flags); 324 status = exitstatus; 325 if (evalskip) 326 goto skipping; 327 } 328 loopnest--; 329 exitstatus = status; 330} 331 332 333 334static void 335evalfor(union node *n, int flags) 336{ 337 struct arglist arglist; 338 union node *argp; 339 struct strlist *sp; 340 struct stackmark smark; 341 342 setstackmark(&smark); 343 arglist.lastp = &arglist.list; 344 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 345 oexitstatus = exitstatus; 346 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 347 if (evalskip) 348 goto out; 349 } 350 *arglist.lastp = NULL; 351 352 exitstatus = 0; 353 loopnest++; 354 for (sp = arglist.list ; sp ; sp = sp->next) { 355 setvar(n->nfor.var, sp->text, 0); 356 evaltree(n->nfor.body, flags); 357 if (evalskip) { 358 if (evalskip == SKIPCONT && --skipcount <= 0) { 359 evalskip = 0; 360 continue; 361 } 362 if (evalskip == SKIPBREAK && --skipcount <= 0) 363 evalskip = 0; 364 break; 365 } 366 } 367 loopnest--; 368out: 369 popstackmark(&smark); 370} 371 372 373 374static void 375evalcase(union node *n, int flags) 376{ 377 union node *cp; 378 union node *patp; 379 struct arglist arglist; 380 struct stackmark smark; 381 382 setstackmark(&smark); 383 arglist.lastp = &arglist.list; 384 oexitstatus = exitstatus; 385 exitstatus = 0; 386 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 387 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 388 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 389 if (casematch(patp, arglist.list->text)) { 390 if (evalskip == 0) { 391 evaltree(cp->nclist.body, flags); 392 } 393 goto out; 394 } 395 } 396 } 397out: 398 popstackmark(&smark); 399} 400 401 402 403/* 404 * Kick off a subshell to evaluate a tree. 405 */ 406 407static void 408evalsubshell(union node *n, int flags) 409{ 410 struct job *jp; 411 int backgnd = (n->type == NBACKGND); 412 413 expredir(n->nredir.redirect); 414 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 415 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 416 if (backgnd) 417 flags &=~ EV_TESTED; 418 redirect(n->nredir.redirect, 0); 419 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 420 } else if (! backgnd) { 421 INTOFF; 422 exitstatus = waitforjob(jp, (int *)NULL); 423 INTON; 424 } 425} 426 427 428/* 429 * Evaluate a redirected compound command. 430 */ 431 432static void 433evalredir(union node *n, int flags) 434{ 435 struct jmploc jmploc; 436 struct jmploc *savehandler; 437 volatile int in_redirect = 1; 438 439 expredir(n->nredir.redirect); 440 savehandler = handler; 441 if (setjmp(jmploc.loc)) { 442 int e; 443 444 handler = savehandler; 445 e = exception; 446 if (e == EXERROR || e == EXEXEC) { 447 popredir(); 448 if (in_redirect) { 449 exitstatus = 2; 450 return; 451 } 452 } 453 longjmp(handler->loc, 1); 454 } else { 455 INTOFF; 456 handler = &jmploc; 457 redirect(n->nredir.redirect, REDIR_PUSH); 458 in_redirect = 0; 459 INTON; 460 evaltree(n->nredir.n, flags); 461 } 462 INTOFF; 463 handler = savehandler; 464 popredir(); 465 INTON; 466} 467 468 469/* 470 * Compute the names of the files in a redirection list. 471 */ 472 473static void 474expredir(union node *n) 475{ 476 union node *redir; 477 478 for (redir = n ; redir ; redir = redir->nfile.next) { 479 struct arglist fn; 480 fn.lastp = &fn.list; 481 oexitstatus = exitstatus; 482 switch (redir->type) { 483 case NFROM: 484 case NTO: 485 case NFROMTO: 486 case NAPPEND: 487 case NCLOBBER: 488 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 489 redir->nfile.expfname = fn.list->text; 490 break; 491 case NFROMFD: 492 case NTOFD: 493 if (redir->ndup.vname) { 494 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 495 fixredir(redir, fn.list->text, 1); 496 } 497 break; 498 } 499 } 500} 501 502 503 504/* 505 * Evaluate a pipeline. All the processes in the pipeline are children 506 * of the process creating the pipeline. (This differs from some versions 507 * of the shell, which make the last process in a pipeline the parent 508 * of all the rest.) 509 */ 510 511static void 512evalpipe(union node *n) 513{ 514 struct job *jp; 515 struct nodelist *lp; 516 int pipelen; 517 int prevfd; 518 int pip[2]; 519 520 TRACE(("evalpipe(%p) called\n", (void *)n)); 521 pipelen = 0; 522 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 523 pipelen++; 524 INTOFF; 525 jp = makejob(n, pipelen); 526 prevfd = -1; 527 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 528 prehash(lp->n); 529 pip[1] = -1; 530 if (lp->next) { 531 if (pipe(pip) < 0) { 532 close(prevfd); 533 error("Pipe call failed: %s", strerror(errno)); 534 } 535 } 536 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 537 INTON; 538 if (prevfd > 0) { 539 dup2(prevfd, 0); 540 close(prevfd); 541 } 542 if (pip[1] >= 0) { 543 if (!(prevfd >= 0 && pip[0] == 0)) 544 close(pip[0]); 545 if (pip[1] != 1) { 546 dup2(pip[1], 1); 547 close(pip[1]); 548 } 549 } 550 evaltree(lp->n, EV_EXIT); 551 } 552 if (prevfd >= 0) 553 close(prevfd); 554 prevfd = pip[0]; 555 close(pip[1]); 556 } 557 INTON; 558 if (n->npipe.backgnd == 0) { 559 INTOFF; 560 exitstatus = waitforjob(jp, (int *)NULL); 561 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 562 INTON; 563 } 564} 565 566 567 568/* 569 * Execute a command inside back quotes. If it's a builtin command, we 570 * want to save its output in a block obtained from malloc. Otherwise 571 * we fork off a subprocess and get the output of the command via a pipe. 572 * Should be called with interrupts off. 573 */ 574 575void 576evalbackcmd(union node *n, struct backcmd *result) 577{ 578 int pip[2]; 579 struct job *jp; 580 struct stackmark smark; /* unnecessary */ 581 struct jmploc jmploc; 582 struct jmploc *savehandler; 583 584 setstackmark(&smark); 585 result->fd = -1; 586 result->buf = NULL; 587 result->nleft = 0; 588 result->jp = NULL; 589 if (n == NULL) { 590 exitstatus = 0; 591 goto out; 592 } 593 if (n->type == NCMD) { 594 exitstatus = oexitstatus; 595 savehandler = handler; 596 if (setjmp(jmploc.loc)) { 597 if (exception == EXERROR || exception == EXEXEC) 598 exitstatus = 2; 599 else if (exception != 0) { 600 handler = savehandler; 601 longjmp(handler->loc, 1); 602 } 603 } else { 604 handler = &jmploc; 605 evalcommand(n, EV_BACKCMD, result); 606 } 607 handler = savehandler; 608 } else { 609 exitstatus = 0; 610 if (pipe(pip) < 0) 611 error("Pipe call failed: %s", strerror(errno)); 612 jp = makejob(n, 1); 613 if (forkshell(jp, n, FORK_NOJOB) == 0) { 614 FORCEINTON; 615 close(pip[0]); 616 if (pip[1] != 1) { 617 dup2(pip[1], 1); 618 close(pip[1]); 619 } 620 evaltree(n, EV_EXIT); 621 } 622 close(pip[1]); 623 result->fd = pip[0]; 624 result->jp = jp; 625 } 626out: 627 popstackmark(&smark); 628 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 629 result->fd, result->buf, result->nleft, result->jp)); 630} 631 632 633 634/* 635 * Execute a simple command. 636 */ 637 638static void 639evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 640{ 641 struct stackmark smark; 642 union node *argp; 643 struct arglist arglist; 644 struct arglist varlist; 645 char **argv; 646 int argc; 647 char **envp; 648 int varflag; 649 struct strlist *sp; 650 int mode; 651 int pip[2]; 652 struct cmdentry cmdentry; 653 struct job *jp; 654 struct jmploc jmploc; 655 struct jmploc *savehandler; 656 char *savecmdname; 657 struct shparam saveparam; 658 struct localvar *savelocalvars; 659 struct parsefile *savetopfile; 660 volatile int e; 661 char *lastarg; 662 int realstatus; 663 int do_clearcmdentry; 664 const char *path = pathval(); 665 666 /* First expand the arguments. */ 667 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 668 setstackmark(&smark); 669 arglist.lastp = &arglist.list; 670 varlist.lastp = &varlist.list; 671 varflag = 1; 672 do_clearcmdentry = 0; 673 oexitstatus = exitstatus; 674 exitstatus = 0; 675 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 676 char *p = argp->narg.text; 677 if (varflag && is_name(*p)) { 678 do { 679 p++; 680 } while (is_in_name(*p)); 681 if (*p == '=') { 682 expandarg(argp, &varlist, EXP_VARTILDE); 683 continue; 684 } 685 } 686 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 687 varflag = 0; 688 } 689 *arglist.lastp = NULL; 690 *varlist.lastp = NULL; 691 expredir(cmd->ncmd.redirect); 692 argc = 0; 693 for (sp = arglist.list ; sp ; sp = sp->next) 694 argc++; 695 argv = stalloc(sizeof (char *) * (argc + 1)); 696 697 for (sp = arglist.list ; sp ; sp = sp->next) { 698 TRACE(("evalcommand arg: %s\n", sp->text)); 699 *argv++ = sp->text; 700 } 701 *argv = NULL; 702 lastarg = NULL; 703 if (iflag && funcnest == 0 && argc > 0) 704 lastarg = argv[-1]; 705 argv -= argc; 706 707 /* Print the command if xflag is set. */ 708 if (xflag) { 709 char sep = 0; 710 const char *p; 711 out2str(ps4val()); 712 for (sp = varlist.list ; sp ; sp = sp->next) { 713 if (sep != 0) 714 out2c(' '); 715 p = strchr(sp->text, '='); 716 if (p != NULL) { 717 p++; 718 outbin(sp->text, p - sp->text, out2); 719 out2qstr(p); 720 } else 721 out2qstr(sp->text); 722 sep = ' '; 723 } 724 for (sp = arglist.list ; sp ; sp = sp->next) { 725 if (sep != 0) 726 out2c(' '); 727 /* Disambiguate command looking like assignment. */ 728 if (sp == arglist.list && 729 strchr(sp->text, '=') != NULL && 730 strchr(sp->text, '\'') == NULL) { 731 out2c('\''); 732 out2str(sp->text); 733 out2c('\''); 734 } else 735 out2qstr(sp->text); 736 sep = ' '; 737 } 738 out2c('\n'); 739 flushout(&errout); 740 } 741 742 /* Now locate the command. */ 743 if (argc == 0) { 744 /* Variable assignment(s) without command */ 745 cmdentry.cmdtype = CMDBUILTIN; 746 cmdentry.u.index = BLTINCMD; 747 cmdentry.special = 0; 748 } else { 749 static const char PATH[] = "PATH="; 750 int cmd_flags = 0, bltinonly = 0; 751 752 /* 753 * Modify the command lookup path, if a PATH= assignment 754 * is present 755 */ 756 for (sp = varlist.list ; sp ; sp = sp->next) 757 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 758 path = sp->text + sizeof(PATH) - 1; 759 /* 760 * On `PATH=... command`, we need to make 761 * sure that the command isn't using the 762 * non-updated hash table of the outer PATH 763 * setting and we need to make sure that 764 * the hash table isn't filled with items 765 * from the temporary setting. 766 * 767 * It would be better to forbit using and 768 * updating the table while this command 769 * runs, by the command finding mechanism 770 * is heavily integrated with hash handling, 771 * so we just delete the hash before and after 772 * the command runs. Partly deleting like 773 * changepatch() does doesn't seem worth the 774 * bookinging effort, since most such runs add 775 * directories in front of the new PATH. 776 */ 777 clearcmdentry(0); 778 do_clearcmdentry = 1; 779 } 780 781 for (;;) { 782 if (bltinonly) { 783 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 784 if (cmdentry.u.index < 0) { 785 cmdentry.u.index = BLTINCMD; 786 argv--; 787 argc++; 788 break; 789 } 790 } else 791 find_command(argv[0], &cmdentry, cmd_flags, path); 792 /* implement the bltin and command builtins here */ 793 if (cmdentry.cmdtype != CMDBUILTIN) 794 break; 795 if (cmdentry.u.index == BLTINCMD) { 796 if (argc == 1) 797 break; 798 argv++; 799 argc--; 800 bltinonly = 1; 801 } else if (cmdentry.u.index == COMMANDCMD) { 802 if (argc == 1) 803 break; 804 if (!strcmp(argv[1], "-p")) { 805 if (argc == 2) 806 break; 807 if (argv[2][0] == '-') { 808 if (strcmp(argv[2], "--")) 809 break; 810 if (argc == 3) 811 break; 812 argv += 3; 813 argc -= 3; 814 } else { 815 argv += 2; 816 argc -= 2; 817 } 818 path = _PATH_STDPATH; 819 clearcmdentry(0); 820 do_clearcmdentry = 1; 821 } else if (!strcmp(argv[1], "--")) { 822 if (argc == 2) 823 break; 824 argv += 2; 825 argc -= 2; 826 } else if (argv[1][0] == '-') 827 break; 828 else { 829 argv++; 830 argc--; 831 } 832 cmd_flags |= DO_NOFUNC; 833 bltinonly = 0; 834 } else 835 break; 836 } 837 /* 838 * Special builtins lose their special properties when 839 * called via 'command'. 840 */ 841 if (cmd_flags & DO_NOFUNC) 842 cmdentry.special = 0; 843 } 844 845 /* Fork off a child process if necessary. */ 846 if (cmd->ncmd.backgnd 847 || ((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 848 && ((flags & EV_EXIT) == 0 || have_traps())) 849 || ((flags & EV_BACKCMD) != 0 850 && (cmdentry.cmdtype != CMDBUILTIN 851 || cmdentry.u.index == CDCMD 852 || cmdentry.u.index == DOTCMD 853 || cmdentry.u.index == EVALCMD))) { 854 jp = makejob(cmd, 1); 855 mode = cmd->ncmd.backgnd; 856 if (flags & EV_BACKCMD) { 857 mode = FORK_NOJOB; 858 if (pipe(pip) < 0) 859 error("Pipe call failed: %s", strerror(errno)); 860 } 861 if (forkshell(jp, cmd, mode) != 0) 862 goto parent; /* at end of routine */ 863 if (flags & EV_BACKCMD) { 864 FORCEINTON; 865 close(pip[0]); 866 if (pip[1] != 1) { 867 dup2(pip[1], 1); 868 close(pip[1]); 869 } 870 } 871 flags |= EV_EXIT; 872 } 873 874 /* This is the child process if a fork occurred. */ 875 /* Execute the command. */ 876 if (cmdentry.cmdtype == CMDFUNCTION) { 877#ifdef DEBUG 878 trputs("Shell function: "); trargs(argv); 879#endif 880 saveparam = shellparam; 881 shellparam.malloc = 0; 882 shellparam.reset = 1; 883 shellparam.nparam = argc - 1; 884 shellparam.p = argv + 1; 885 shellparam.optnext = NULL; 886 INTOFF; 887 savelocalvars = localvars; 888 localvars = NULL; 889 reffunc(cmdentry.u.func); 890 savehandler = handler; 891 if (setjmp(jmploc.loc)) { 892 if (exception == EXSHELLPROC) 893 freeparam(&saveparam); 894 else { 895 freeparam(&shellparam); 896 shellparam = saveparam; 897 if (exception == EXERROR || exception == EXEXEC) 898 popredir(); 899 } 900 unreffunc(cmdentry.u.func); 901 poplocalvars(); 902 localvars = savelocalvars; 903 funcnest--; 904 handler = savehandler; 905 longjmp(handler->loc, 1); 906 } 907 handler = &jmploc; 908 funcnest++; 909 redirect(cmd->ncmd.redirect, REDIR_PUSH); 910 INTON; 911 for (sp = varlist.list ; sp ; sp = sp->next) 912 mklocal(sp->text); 913 exitstatus = oexitstatus; 914 if (flags & EV_TESTED) 915 evaltree(getfuncnode(cmdentry.u.func), EV_TESTED); 916 else 917 evaltree(getfuncnode(cmdentry.u.func), 0); 918 INTOFF; 919 unreffunc(cmdentry.u.func); 920 poplocalvars(); 921 localvars = savelocalvars; 922 freeparam(&shellparam); 923 shellparam = saveparam; 924 handler = savehandler; 925 funcnest--; 926 popredir(); 927 INTON; 928 if (evalskip == SKIPFUNC) { 929 evalskip = 0; 930 skipcount = 0; 931 } 932 if (flags & EV_EXIT) 933 exitshell(exitstatus); 934 } else if (cmdentry.cmdtype == CMDBUILTIN) { 935#ifdef DEBUG 936 trputs("builtin command: "); trargs(argv); 937#endif 938 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 939 if (flags == EV_BACKCMD) { 940 memout.nleft = 0; 941 memout.nextc = memout.buf; 942 memout.bufsize = 64; 943 mode |= REDIR_BACKQ; 944 cmdentry.special = 0; 945 } 946 savecmdname = commandname; 947 savetopfile = getcurrentfile(); 948 cmdenviron = varlist.list; 949 e = -1; 950 savehandler = handler; 951 if (setjmp(jmploc.loc)) { 952 e = exception; 953 exitstatus = (e == EXINT)? SIGINT+128 : 2; 954 goto cmddone; 955 } 956 handler = &jmploc; 957 redirect(cmd->ncmd.redirect, mode); 958 /* 959 * If there is no command word, redirection errors should 960 * not be fatal but assignment errors should. 961 */ 962 if (argc == 0 && !(flags & EV_BACKCMD)) 963 cmdentry.special = 1; 964 if (cmdentry.special) 965 listsetvar(cmdenviron); 966 if (argc > 0) 967 bltinsetlocale(); 968 commandname = argv[0]; 969 argptr = argv + 1; 970 nextopt_optptr = NULL; /* initialize nextopt */ 971 builtin_flags = flags; 972 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 973 flushall(); 974cmddone: 975 if (argc > 0) 976 bltinunsetlocale(); 977 cmdenviron = NULL; 978 out1 = &output; 979 out2 = &errout; 980 freestdout(); 981 if (e != EXSHELLPROC) { 982 commandname = savecmdname; 983 if (flags & EV_EXIT) { 984 exitshell(exitstatus); 985 } 986 } 987 handler = savehandler; 988 if (flags == EV_BACKCMD) { 989 backcmd->buf = memout.buf; 990 backcmd->nleft = memout.nextc - memout.buf; 991 memout.buf = NULL; 992 } 993 if (cmdentry.u.index != EXECCMD && 994 (e == -1 || e == EXERROR || e == EXEXEC)) 995 popredir(); 996 if (e != -1) { 997 if ((e != EXERROR && e != EXEXEC) 998 || cmdentry.special) 999 exraise(e); 1000 popfilesupto(savetopfile); 1001 if (flags != EV_BACKCMD) 1002 FORCEINTON; 1003 } 1004 } else { 1005#ifdef DEBUG 1006 trputs("normal command: "); trargs(argv); 1007#endif 1008 redirect(cmd->ncmd.redirect, 0); 1009 for (sp = varlist.list ; sp ; sp = sp->next) 1010 setvareq(sp->text, VEXPORT|VSTACK); 1011 envp = environment(); 1012 shellexec(argv, envp, path, cmdentry.u.index); 1013 /*NOTREACHED*/ 1014 } 1015 goto out; 1016 1017parent: /* parent process gets here (if we forked) */ 1018 if (mode == FORK_FG) { /* argument to fork */ 1019 INTOFF; 1020 exitstatus = waitforjob(jp, &realstatus); 1021 INTON; 1022 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1023 evalskip = SKIPBREAK; 1024 skipcount = loopnest; 1025 } 1026 } else if (mode == FORK_NOJOB) { 1027 backcmd->fd = pip[0]; 1028 close(pip[1]); 1029 backcmd->jp = jp; 1030 } 1031 1032out: 1033 if (lastarg) 1034 setvar("_", lastarg, 0); 1035 if (do_clearcmdentry) 1036 clearcmdentry(0); 1037 popstackmark(&smark); 1038} 1039 1040 1041 1042/* 1043 * Search for a command. This is called before we fork so that the 1044 * location of the command will be available in the parent as well as 1045 * the child. The check for "goodname" is an overly conservative 1046 * check that the name will not be subject to expansion. 1047 */ 1048 1049static void 1050prehash(union node *n) 1051{ 1052 struct cmdentry entry; 1053 1054 if (n && n->type == NCMD && n->ncmd.args) 1055 if (goodname(n->ncmd.args->narg.text)) 1056 find_command(n->ncmd.args->narg.text, &entry, 0, 1057 pathval()); 1058} 1059 1060 1061 1062/* 1063 * Builtin commands. Builtin commands whose functions are closely 1064 * tied to evaluation are implemented here. 1065 */ 1066 1067/* 1068 * No command given, a bltin command with no arguments, or a bltin command 1069 * with an invalid name. 1070 */ 1071 1072int 1073bltincmd(int argc, char **argv) 1074{ 1075 if (argc > 1) { 1076 out2fmt_flush("%s: not found\n", argv[1]); 1077 return 127; 1078 } 1079 /* 1080 * Preserve exitstatus of a previous possible redirection 1081 * as POSIX mandates 1082 */ 1083 return exitstatus; 1084} 1085 1086 1087/* 1088 * Handle break and continue commands. Break, continue, and return are 1089 * all handled by setting the evalskip flag. The evaluation routines 1090 * above all check this flag, and if it is set they start skipping 1091 * commands rather than executing them. The variable skipcount is 1092 * the number of loops to break/continue, or the number of function 1093 * levels to return. (The latter is always 1.) It should probably 1094 * be an error to break out of more loops than exist, but it isn't 1095 * in the standard shell so we don't make it one here. 1096 */ 1097 1098int 1099breakcmd(int argc, char **argv) 1100{ 1101 int n = argc > 1 ? number(argv[1]) : 1; 1102 1103 if (n > loopnest) 1104 n = loopnest; 1105 if (n > 0) { 1106 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1107 skipcount = n; 1108 } 1109 return 0; 1110} 1111 1112/* 1113 * The `command' command. 1114 */ 1115int 1116commandcmd(int argc, char **argv) 1117{ 1118 const char *path; 1119 int ch; 1120 int cmd = -1; 1121 1122 path = bltinlookup("PATH", 1); 1123 1124 optind = optreset = 1; 1125 opterr = 0; 1126 while ((ch = getopt(argc, argv, "pvV")) != -1) { 1127 switch (ch) { 1128 case 'p': 1129 path = _PATH_STDPATH; 1130 break; 1131 case 'v': 1132 cmd = TYPECMD_SMALLV; 1133 break; 1134 case 'V': 1135 cmd = TYPECMD_BIGV; 1136 break; 1137 case '?': 1138 default: 1139 error("unknown option: -%c", optopt); 1140 } 1141 } 1142 argc -= optind; 1143 argv += optind; 1144 1145 if (cmd != -1) { 1146 if (argc != 1) 1147 error("wrong number of arguments"); 1148 return typecmd_impl(2, argv - 1, cmd, path); 1149 } 1150 if (argc != 0) 1151 error("commandcmd bad call"); 1152 1153 /* 1154 * Do nothing successfully if no command was specified; 1155 * ksh also does this. 1156 */ 1157 return 0; 1158} 1159 1160 1161/* 1162 * The return command. 1163 */ 1164 1165int 1166returncmd(int argc, char **argv) 1167{ 1168 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1169 1170 if (funcnest) { 1171 evalskip = SKIPFUNC; 1172 skipcount = 1; 1173 } else { 1174 /* skip the rest of the file */ 1175 evalskip = SKIPFILE; 1176 skipcount = 1; 1177 } 1178 return ret; 1179} 1180 1181 1182int 1183falsecmd(int argc __unused, char **argv __unused) 1184{ 1185 return 1; 1186} 1187 1188 1189int 1190truecmd(int argc __unused, char **argv __unused) 1191{ 1192 return 0; 1193} 1194 1195 1196int 1197execcmd(int argc, char **argv) 1198{ 1199 /* 1200 * Because we have historically not supported any options, 1201 * only treat "--" specially. 1202 */ 1203 if (argc > 1 && strcmp(argv[1], "--") == 0) 1204 argc--, argv++; 1205 if (argc > 1) { 1206 struct strlist *sp; 1207 1208 iflag = 0; /* exit on error */ 1209 mflag = 0; 1210 optschanged(); 1211 for (sp = cmdenviron; sp ; sp = sp->next) 1212 setvareq(sp->text, VEXPORT|VSTACK); 1213 shellexec(argv + 1, environment(), pathval(), 0); 1214 1215 } 1216 return 0; 1217} 1218 1219 1220int 1221timescmd(int argc __unused, char **argv __unused) 1222{ 1223 struct rusage ru; 1224 long shumins, shsmins, chumins, chsmins; 1225 double shusecs, shssecs, chusecs, chssecs; 1226 1227 if (getrusage(RUSAGE_SELF, &ru) < 0) 1228 return 1; 1229 shumins = ru.ru_utime.tv_sec / 60; 1230 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1231 shsmins = ru.ru_stime.tv_sec / 60; 1232 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1233 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1234 return 1; 1235 chumins = ru.ru_utime.tv_sec / 60; 1236 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1237 chsmins = ru.ru_stime.tv_sec / 60; 1238 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1239 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1240 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1241 return 0; 1242} 1243