eval.c revision 214600
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 214600 2010-10-31 12:08:16Z 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 while (*p) 139 STPUTC(*p++, concat); 140 if ((p = *ap++) == NULL) 141 break; 142 STPUTC(' ', concat); 143 } 144 STPUTC('\0', concat); 145 p = grabstackstr(concat); 146 } 147 evalstring(p, builtin_flags & EV_TESTED); 148 } else 149 exitstatus = 0; 150 return exitstatus; 151} 152 153 154/* 155 * Execute a command or commands contained in a string. 156 */ 157 158void 159evalstring(char *s, int flags) 160{ 161 union node *n; 162 struct stackmark smark; 163 int flags_exit; 164 int any; 165 166 flags_exit = flags & EV_EXIT; 167 flags &= ~EV_EXIT; 168 any = 0; 169 setstackmark(&smark); 170 setinputstring(s, 1); 171 while ((n = parsecmd(0)) != NEOF) { 172 if (n != NULL) { 173 if (flags_exit && preadateof()) 174 evaltree(n, flags | EV_EXIT); 175 else 176 evaltree(n, flags); 177 any = 1; 178 } 179 popstackmark(&smark); 180 } 181 popfile(); 182 popstackmark(&smark); 183 if (!any) 184 exitstatus = 0; 185 if (flags_exit) 186 exitshell(exitstatus); 187} 188 189 190/* 191 * Evaluate a parse tree. The value is left in the global variable 192 * exitstatus. 193 */ 194 195void 196evaltree(union node *n, int flags) 197{ 198 int do_etest; 199 union node *next; 200 201 do_etest = 0; 202 if (n == NULL) { 203 TRACE(("evaltree(NULL) called\n")); 204 exitstatus = 0; 205 goto out; 206 } 207 do { 208 next = NULL; 209#ifndef NO_HISTORY 210 displayhist = 1; /* show history substitutions done with fc */ 211#endif 212 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 213 switch (n->type) { 214 case NSEMI: 215 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 216 if (evalskip) 217 goto out; 218 next = n->nbinary.ch2; 219 break; 220 case NAND: 221 evaltree(n->nbinary.ch1, EV_TESTED); 222 if (evalskip || exitstatus != 0) { 223 goto out; 224 } 225 next = n->nbinary.ch2; 226 break; 227 case NOR: 228 evaltree(n->nbinary.ch1, EV_TESTED); 229 if (evalskip || exitstatus == 0) 230 goto out; 231 next = n->nbinary.ch2; 232 break; 233 case NREDIR: 234 evalredir(n, flags); 235 break; 236 case NSUBSHELL: 237 evalsubshell(n, flags); 238 do_etest = !(flags & EV_TESTED); 239 break; 240 case NBACKGND: 241 evalsubshell(n, flags); 242 break; 243 case NIF: { 244 evaltree(n->nif.test, EV_TESTED); 245 if (evalskip) 246 goto out; 247 if (exitstatus == 0) 248 next = n->nif.ifpart; 249 else if (n->nif.elsepart) 250 next = n->nif.elsepart; 251 else 252 exitstatus = 0; 253 break; 254 } 255 case NWHILE: 256 case NUNTIL: 257 evalloop(n, flags & ~EV_EXIT); 258 break; 259 case NFOR: 260 evalfor(n, flags & ~EV_EXIT); 261 break; 262 case NCASE: 263 evalcase(n, flags); 264 break; 265 case NDEFUN: 266 defun(n->narg.text, n->narg.next); 267 exitstatus = 0; 268 break; 269 case NNOT: 270 evaltree(n->nnot.com, EV_TESTED); 271 exitstatus = !exitstatus; 272 break; 273 274 case NPIPE: 275 evalpipe(n); 276 do_etest = !(flags & EV_TESTED); 277 break; 278 case NCMD: 279 evalcommand(n, flags, (struct backcmd *)NULL); 280 do_etest = !(flags & EV_TESTED); 281 break; 282 default: 283 out1fmt("Node type = %d\n", n->type); 284 flushout(&output); 285 break; 286 } 287 n = next; 288 } while (n != NULL); 289out: 290 if (pendingsigs) 291 dotrap(); 292 if ((flags & EV_EXIT) || (eflag && exitstatus != 0 && do_etest)) 293 exitshell(exitstatus); 294} 295 296 297static void 298evalloop(union node *n, int flags) 299{ 300 int status; 301 302 loopnest++; 303 status = 0; 304 for (;;) { 305 evaltree(n->nbinary.ch1, EV_TESTED); 306 if (evalskip) { 307skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 308 evalskip = 0; 309 continue; 310 } 311 if (evalskip == SKIPBREAK && --skipcount <= 0) 312 evalskip = 0; 313 if (evalskip == SKIPFUNC || evalskip == SKIPFILE) 314 status = exitstatus; 315 break; 316 } 317 if (n->type == NWHILE) { 318 if (exitstatus != 0) 319 break; 320 } else { 321 if (exitstatus == 0) 322 break; 323 } 324 evaltree(n->nbinary.ch2, flags); 325 status = exitstatus; 326 if (evalskip) 327 goto skipping; 328 } 329 loopnest--; 330 exitstatus = status; 331} 332 333 334 335static void 336evalfor(union node *n, int flags) 337{ 338 struct arglist arglist; 339 union node *argp; 340 struct strlist *sp; 341 struct stackmark smark; 342 343 setstackmark(&smark); 344 arglist.lastp = &arglist.list; 345 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 346 oexitstatus = exitstatus; 347 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 348 if (evalskip) 349 goto out; 350 } 351 *arglist.lastp = NULL; 352 353 exitstatus = 0; 354 loopnest++; 355 for (sp = arglist.list ; sp ; sp = sp->next) { 356 setvar(n->nfor.var, sp->text, 0); 357 evaltree(n->nfor.body, flags); 358 if (evalskip) { 359 if (evalskip == SKIPCONT && --skipcount <= 0) { 360 evalskip = 0; 361 continue; 362 } 363 if (evalskip == SKIPBREAK && --skipcount <= 0) 364 evalskip = 0; 365 break; 366 } 367 } 368 loopnest--; 369out: 370 popstackmark(&smark); 371} 372 373 374 375static void 376evalcase(union node *n, int flags) 377{ 378 union node *cp; 379 union node *patp; 380 struct arglist arglist; 381 struct stackmark smark; 382 383 setstackmark(&smark); 384 arglist.lastp = &arglist.list; 385 oexitstatus = exitstatus; 386 exitstatus = 0; 387 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 388 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 389 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 390 if (casematch(patp, arglist.list->text)) { 391 if (evalskip == 0) { 392 evaltree(cp->nclist.body, flags); 393 } 394 goto out; 395 } 396 } 397 } 398out: 399 popstackmark(&smark); 400} 401 402 403 404/* 405 * Kick off a subshell to evaluate a tree. 406 */ 407 408static void 409evalsubshell(union node *n, int flags) 410{ 411 struct job *jp; 412 int backgnd = (n->type == NBACKGND); 413 414 expredir(n->nredir.redirect); 415 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 416 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 417 if (backgnd) 418 flags &=~ EV_TESTED; 419 redirect(n->nredir.redirect, 0); 420 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 421 } else if (! backgnd) { 422 INTOFF; 423 exitstatus = waitforjob(jp, (int *)NULL); 424 INTON; 425 } 426} 427 428 429/* 430 * Evaluate a redirected compound command. 431 */ 432 433static void 434evalredir(union node *n, int flags) 435{ 436 struct jmploc jmploc; 437 struct jmploc *savehandler; 438 volatile int in_redirect = 1; 439 440 expredir(n->nredir.redirect); 441 savehandler = handler; 442 if (setjmp(jmploc.loc)) { 443 int e; 444 445 handler = savehandler; 446 e = exception; 447 if (e == EXERROR || e == EXEXEC) { 448 popredir(); 449 if (in_redirect) { 450 exitstatus = 2; 451 return; 452 } 453 } 454 longjmp(handler->loc, 1); 455 } else { 456 INTOFF; 457 handler = &jmploc; 458 redirect(n->nredir.redirect, REDIR_PUSH); 459 in_redirect = 0; 460 INTON; 461 evaltree(n->nredir.n, flags); 462 } 463 INTOFF; 464 handler = savehandler; 465 popredir(); 466 INTON; 467} 468 469 470/* 471 * Compute the names of the files in a redirection list. 472 */ 473 474static void 475expredir(union node *n) 476{ 477 union node *redir; 478 479 for (redir = n ; redir ; redir = redir->nfile.next) { 480 struct arglist fn; 481 fn.lastp = &fn.list; 482 oexitstatus = exitstatus; 483 switch (redir->type) { 484 case NFROM: 485 case NTO: 486 case NFROMTO: 487 case NAPPEND: 488 case NCLOBBER: 489 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 490 redir->nfile.expfname = fn.list->text; 491 break; 492 case NFROMFD: 493 case NTOFD: 494 if (redir->ndup.vname) { 495 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 496 fixredir(redir, fn.list->text, 1); 497 } 498 break; 499 } 500 } 501} 502 503 504 505/* 506 * Evaluate a pipeline. All the processes in the pipeline are children 507 * of the process creating the pipeline. (This differs from some versions 508 * of the shell, which make the last process in a pipeline the parent 509 * of all the rest.) 510 */ 511 512static void 513evalpipe(union node *n) 514{ 515 struct job *jp; 516 struct nodelist *lp; 517 int pipelen; 518 int prevfd; 519 int pip[2]; 520 521 TRACE(("evalpipe(%p) called\n", (void *)n)); 522 pipelen = 0; 523 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 524 pipelen++; 525 INTOFF; 526 jp = makejob(n, pipelen); 527 prevfd = -1; 528 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 529 prehash(lp->n); 530 pip[1] = -1; 531 if (lp->next) { 532 if (pipe(pip) < 0) { 533 close(prevfd); 534 error("Pipe call failed: %s", strerror(errno)); 535 } 536 } 537 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 538 INTON; 539 if (prevfd > 0) { 540 dup2(prevfd, 0); 541 close(prevfd); 542 } 543 if (pip[1] >= 0) { 544 if (!(prevfd >= 0 && pip[0] == 0)) 545 close(pip[0]); 546 if (pip[1] != 1) { 547 dup2(pip[1], 1); 548 close(pip[1]); 549 } 550 } 551 evaltree(lp->n, EV_EXIT); 552 } 553 if (prevfd >= 0) 554 close(prevfd); 555 prevfd = pip[0]; 556 close(pip[1]); 557 } 558 INTON; 559 if (n->npipe.backgnd == 0) { 560 INTOFF; 561 exitstatus = waitforjob(jp, (int *)NULL); 562 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 563 INTON; 564 } 565} 566 567 568 569/* 570 * Execute a command inside back quotes. If it's a builtin command, we 571 * want to save its output in a block obtained from malloc. Otherwise 572 * we fork off a subprocess and get the output of the command via a pipe. 573 * Should be called with interrupts off. 574 */ 575 576void 577evalbackcmd(union node *n, struct backcmd *result) 578{ 579 int pip[2]; 580 struct job *jp; 581 struct stackmark smark; /* unnecessary */ 582 583 setstackmark(&smark); 584 result->fd = -1; 585 result->buf = NULL; 586 result->nleft = 0; 587 result->jp = NULL; 588 if (n == NULL) { 589 exitstatus = 0; 590 goto out; 591 } 592 if (n->type == NCMD) { 593 exitstatus = oexitstatus; 594 evalcommand(n, EV_BACKCMD, result); 595 } else { 596 exitstatus = 0; 597 if (pipe(pip) < 0) 598 error("Pipe call failed: %s", strerror(errno)); 599 jp = makejob(n, 1); 600 if (forkshell(jp, n, FORK_NOJOB) == 0) { 601 FORCEINTON; 602 close(pip[0]); 603 if (pip[1] != 1) { 604 dup2(pip[1], 1); 605 close(pip[1]); 606 } 607 evaltree(n, EV_EXIT); 608 } 609 close(pip[1]); 610 result->fd = pip[0]; 611 result->jp = jp; 612 } 613out: 614 popstackmark(&smark); 615 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 616 result->fd, result->buf, result->nleft, result->jp)); 617} 618 619 620 621/* 622 * Execute a simple command. 623 */ 624 625static void 626evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 627{ 628 struct stackmark smark; 629 union node *argp; 630 struct arglist arglist; 631 struct arglist varlist; 632 char **argv; 633 int argc; 634 char **envp; 635 int varflag; 636 struct strlist *sp; 637 int mode; 638 int pip[2]; 639 struct cmdentry cmdentry; 640 struct job *jp; 641 struct jmploc jmploc; 642 struct jmploc *savehandler; 643 char *savecmdname; 644 struct shparam saveparam; 645 struct localvar *savelocalvars; 646 struct parsefile *savetopfile; 647 volatile int e; 648 char *lastarg; 649 int realstatus; 650 int do_clearcmdentry; 651 const char *path = pathval(); 652 653 /* First expand the arguments. */ 654 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 655 setstackmark(&smark); 656 arglist.lastp = &arglist.list; 657 varlist.lastp = &varlist.list; 658 varflag = 1; 659 do_clearcmdentry = 0; 660 oexitstatus = exitstatus; 661 exitstatus = 0; 662 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 663 char *p = argp->narg.text; 664 if (varflag && is_name(*p)) { 665 do { 666 p++; 667 } while (is_in_name(*p)); 668 if (*p == '=') { 669 expandarg(argp, &varlist, EXP_VARTILDE); 670 continue; 671 } 672 } 673 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 674 varflag = 0; 675 } 676 *arglist.lastp = NULL; 677 *varlist.lastp = NULL; 678 expredir(cmd->ncmd.redirect); 679 argc = 0; 680 for (sp = arglist.list ; sp ; sp = sp->next) 681 argc++; 682 argv = stalloc(sizeof (char *) * (argc + 1)); 683 684 for (sp = arglist.list ; sp ; sp = sp->next) { 685 TRACE(("evalcommand arg: %s\n", sp->text)); 686 *argv++ = sp->text; 687 } 688 *argv = NULL; 689 lastarg = NULL; 690 if (iflag && funcnest == 0 && argc > 0) 691 lastarg = argv[-1]; 692 argv -= argc; 693 694 /* Print the command if xflag is set. */ 695 if (xflag) { 696 char sep = 0; 697 const char *p; 698 out2str(ps4val()); 699 for (sp = varlist.list ; sp ; sp = sp->next) { 700 if (sep != 0) 701 out2c(' '); 702 p = sp->text; 703 while (*p != '=' && *p != '\0') 704 out2c(*p++); 705 if (*p != '\0') { 706 out2c(*p++); 707 out2qstr(p); 708 } 709 sep = ' '; 710 } 711 for (sp = arglist.list ; sp ; sp = sp->next) { 712 if (sep != 0) 713 out2c(' '); 714 /* Disambiguate command looking like assignment. */ 715 if (sp == arglist.list && 716 strchr(sp->text, '=') != NULL && 717 strchr(sp->text, '\'') == NULL) { 718 out2c('\''); 719 out2str(sp->text); 720 out2c('\''); 721 } else 722 out2qstr(sp->text); 723 sep = ' '; 724 } 725 out2c('\n'); 726 flushout(&errout); 727 } 728 729 /* Now locate the command. */ 730 if (argc == 0) { 731 /* Variable assignment(s) without command */ 732 cmdentry.cmdtype = CMDBUILTIN; 733 cmdentry.u.index = BLTINCMD; 734 cmdentry.special = 0; 735 } else { 736 static const char PATH[] = "PATH="; 737 int cmd_flags = 0, bltinonly = 0; 738 739 /* 740 * Modify the command lookup path, if a PATH= assignment 741 * is present 742 */ 743 for (sp = varlist.list ; sp ; sp = sp->next) 744 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 745 path = sp->text + sizeof(PATH) - 1; 746 /* 747 * On `PATH=... command`, we need to make 748 * sure that the command isn't using the 749 * non-updated hash table of the outer PATH 750 * setting and we need to make sure that 751 * the hash table isn't filled with items 752 * from the temporary setting. 753 * 754 * It would be better to forbit using and 755 * updating the table while this command 756 * runs, by the command finding mechanism 757 * is heavily integrated with hash handling, 758 * so we just delete the hash before and after 759 * the command runs. Partly deleting like 760 * changepatch() does doesn't seem worth the 761 * bookinging effort, since most such runs add 762 * directories in front of the new PATH. 763 */ 764 clearcmdentry(0); 765 do_clearcmdentry = 1; 766 } 767 768 for (;;) { 769 if (bltinonly) { 770 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 771 if (cmdentry.u.index < 0) { 772 cmdentry.u.index = BLTINCMD; 773 argv--; 774 argc++; 775 break; 776 } 777 } else 778 find_command(argv[0], &cmdentry, cmd_flags, path); 779 /* implement the bltin and command builtins here */ 780 if (cmdentry.cmdtype != CMDBUILTIN) 781 break; 782 if (cmdentry.u.index == BLTINCMD) { 783 if (argc == 1) 784 break; 785 argv++; 786 argc--; 787 bltinonly = 1; 788 } else if (cmdentry.u.index == COMMANDCMD) { 789 if (argc == 1) 790 break; 791 if (!strcmp(argv[1], "-p")) { 792 if (argc == 2) 793 break; 794 if (argv[2][0] == '-') { 795 if (strcmp(argv[2], "--")) 796 break; 797 if (argc == 3) 798 break; 799 argv += 3; 800 argc -= 3; 801 } else { 802 argv += 2; 803 argc -= 2; 804 } 805 path = _PATH_STDPATH; 806 clearcmdentry(0); 807 do_clearcmdentry = 1; 808 } else if (!strcmp(argv[1], "--")) { 809 if (argc == 2) 810 break; 811 argv += 2; 812 argc -= 2; 813 } else if (argv[1][0] == '-') 814 break; 815 else { 816 argv++; 817 argc--; 818 } 819 cmd_flags |= DO_NOFUNC; 820 bltinonly = 0; 821 } else 822 break; 823 } 824 /* 825 * Special builtins lose their special properties when 826 * called via 'command'. 827 */ 828 if (cmd_flags & DO_NOFUNC) 829 cmdentry.special = 0; 830 } 831 832 /* Fork off a child process if necessary. */ 833 if (cmd->ncmd.backgnd 834 || ((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 835 && ((flags & EV_EXIT) == 0 || have_traps())) 836 || ((flags & EV_BACKCMD) != 0 837 && (cmdentry.cmdtype != CMDBUILTIN 838 || cmdentry.u.index == CDCMD 839 || cmdentry.u.index == DOTCMD 840 || cmdentry.u.index == EVALCMD))) { 841 jp = makejob(cmd, 1); 842 mode = cmd->ncmd.backgnd; 843 if (flags & EV_BACKCMD) { 844 mode = FORK_NOJOB; 845 if (pipe(pip) < 0) 846 error("Pipe call failed: %s", strerror(errno)); 847 } 848 if (forkshell(jp, cmd, mode) != 0) 849 goto parent; /* at end of routine */ 850 if (flags & EV_BACKCMD) { 851 FORCEINTON; 852 close(pip[0]); 853 if (pip[1] != 1) { 854 dup2(pip[1], 1); 855 close(pip[1]); 856 } 857 } 858 flags |= EV_EXIT; 859 } 860 861 /* This is the child process if a fork occurred. */ 862 /* Execute the command. */ 863 if (cmdentry.cmdtype == CMDFUNCTION) { 864#ifdef DEBUG 865 trputs("Shell function: "); trargs(argv); 866#endif 867 saveparam = shellparam; 868 shellparam.malloc = 0; 869 shellparam.reset = 1; 870 shellparam.nparam = argc - 1; 871 shellparam.p = argv + 1; 872 shellparam.optnext = NULL; 873 INTOFF; 874 savelocalvars = localvars; 875 localvars = NULL; 876 reffunc(cmdentry.u.func); 877 savehandler = handler; 878 if (setjmp(jmploc.loc)) { 879 if (exception == EXSHELLPROC) 880 freeparam(&saveparam); 881 else { 882 freeparam(&shellparam); 883 shellparam = saveparam; 884 if (exception == EXERROR || exception == EXEXEC) 885 popredir(); 886 } 887 unreffunc(cmdentry.u.func); 888 poplocalvars(); 889 localvars = savelocalvars; 890 funcnest--; 891 handler = savehandler; 892 longjmp(handler->loc, 1); 893 } 894 handler = &jmploc; 895 funcnest++; 896 redirect(cmd->ncmd.redirect, REDIR_PUSH); 897 INTON; 898 for (sp = varlist.list ; sp ; sp = sp->next) 899 mklocal(sp->text); 900 exitstatus = oexitstatus; 901 if (flags & EV_TESTED) 902 evaltree(getfuncnode(cmdentry.u.func), EV_TESTED); 903 else 904 evaltree(getfuncnode(cmdentry.u.func), 0); 905 INTOFF; 906 unreffunc(cmdentry.u.func); 907 poplocalvars(); 908 localvars = savelocalvars; 909 freeparam(&shellparam); 910 shellparam = saveparam; 911 handler = savehandler; 912 funcnest--; 913 popredir(); 914 INTON; 915 if (evalskip == SKIPFUNC) { 916 evalskip = 0; 917 skipcount = 0; 918 } 919 if (flags & EV_EXIT) 920 exitshell(exitstatus); 921 } else if (cmdentry.cmdtype == CMDBUILTIN) { 922#ifdef DEBUG 923 trputs("builtin command: "); trargs(argv); 924#endif 925 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 926 if (flags == EV_BACKCMD) { 927 memout.nleft = 0; 928 memout.nextc = memout.buf; 929 memout.bufsize = 64; 930 mode |= REDIR_BACKQ; 931 cmdentry.special = 0; 932 } 933 savecmdname = commandname; 934 savetopfile = getcurrentfile(); 935 cmdenviron = varlist.list; 936 e = -1; 937 savehandler = handler; 938 if (setjmp(jmploc.loc)) { 939 e = exception; 940 exitstatus = (e == EXINT)? SIGINT+128 : 2; 941 goto cmddone; 942 } 943 handler = &jmploc; 944 redirect(cmd->ncmd.redirect, mode); 945 /* 946 * If there is no command word, redirection errors should 947 * not be fatal but assignment errors should. 948 */ 949 if (argc == 0 && !(flags & EV_BACKCMD)) 950 cmdentry.special = 1; 951 if (cmdentry.special) 952 listsetvar(cmdenviron); 953 if (argc > 0) 954 bltinsetlocale(); 955 commandname = argv[0]; 956 argptr = argv + 1; 957 nextopt_optptr = NULL; /* initialize nextopt */ 958 builtin_flags = flags; 959 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 960 flushall(); 961cmddone: 962 if (argc > 0) 963 bltinunsetlocale(); 964 cmdenviron = NULL; 965 out1 = &output; 966 out2 = &errout; 967 freestdout(); 968 if (e != EXSHELLPROC) { 969 commandname = savecmdname; 970 if (flags & EV_EXIT) { 971 exitshell(exitstatus); 972 } 973 } 974 handler = savehandler; 975 if (flags == EV_BACKCMD) { 976 backcmd->buf = memout.buf; 977 backcmd->nleft = memout.nextc - memout.buf; 978 memout.buf = NULL; 979 } 980 if (cmdentry.u.index != EXECCMD && 981 (e == -1 || e == EXERROR || e == EXEXEC)) 982 popredir(); 983 if (e != -1) { 984 if ((e != EXERROR && e != EXEXEC) 985 || cmdentry.special) 986 exraise(e); 987 popfilesupto(savetopfile); 988 if (flags != EV_BACKCMD) 989 FORCEINTON; 990 } 991 } else { 992#ifdef DEBUG 993 trputs("normal command: "); trargs(argv); 994#endif 995 redirect(cmd->ncmd.redirect, 0); 996 for (sp = varlist.list ; sp ; sp = sp->next) 997 setvareq(sp->text, VEXPORT|VSTACK); 998 envp = environment(); 999 shellexec(argv, envp, path, cmdentry.u.index); 1000 /*NOTREACHED*/ 1001 } 1002 goto out; 1003 1004parent: /* parent process gets here (if we forked) */ 1005 if (mode == FORK_FG) { /* argument to fork */ 1006 INTOFF; 1007 exitstatus = waitforjob(jp, &realstatus); 1008 INTON; 1009 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1010 evalskip = SKIPBREAK; 1011 skipcount = loopnest; 1012 } 1013 } else if (mode == FORK_NOJOB) { 1014 backcmd->fd = pip[0]; 1015 close(pip[1]); 1016 backcmd->jp = jp; 1017 } 1018 1019out: 1020 if (lastarg) 1021 setvar("_", lastarg, 0); 1022 if (do_clearcmdentry) 1023 clearcmdentry(0); 1024 popstackmark(&smark); 1025} 1026 1027 1028 1029/* 1030 * Search for a command. This is called before we fork so that the 1031 * location of the command will be available in the parent as well as 1032 * the child. The check for "goodname" is an overly conservative 1033 * check that the name will not be subject to expansion. 1034 */ 1035 1036static void 1037prehash(union node *n) 1038{ 1039 struct cmdentry entry; 1040 1041 if (n && n->type == NCMD && n->ncmd.args) 1042 if (goodname(n->ncmd.args->narg.text)) 1043 find_command(n->ncmd.args->narg.text, &entry, 0, 1044 pathval()); 1045} 1046 1047 1048 1049/* 1050 * Builtin commands. Builtin commands whose functions are closely 1051 * tied to evaluation are implemented here. 1052 */ 1053 1054/* 1055 * No command given, a bltin command with no arguments, or a bltin command 1056 * with an invalid name. 1057 */ 1058 1059int 1060bltincmd(int argc, char **argv) 1061{ 1062 if (argc > 1) { 1063 out2fmt_flush("%s: not found\n", argv[1]); 1064 return 127; 1065 } 1066 /* 1067 * Preserve exitstatus of a previous possible redirection 1068 * as POSIX mandates 1069 */ 1070 return exitstatus; 1071} 1072 1073 1074/* 1075 * Handle break and continue commands. Break, continue, and return are 1076 * all handled by setting the evalskip flag. The evaluation routines 1077 * above all check this flag, and if it is set they start skipping 1078 * commands rather than executing them. The variable skipcount is 1079 * the number of loops to break/continue, or the number of function 1080 * levels to return. (The latter is always 1.) It should probably 1081 * be an error to break out of more loops than exist, but it isn't 1082 * in the standard shell so we don't make it one here. 1083 */ 1084 1085int 1086breakcmd(int argc, char **argv) 1087{ 1088 int n = argc > 1 ? number(argv[1]) : 1; 1089 1090 if (n > loopnest) 1091 n = loopnest; 1092 if (n > 0) { 1093 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1094 skipcount = n; 1095 } 1096 return 0; 1097} 1098 1099/* 1100 * The `command' command. 1101 */ 1102int 1103commandcmd(int argc, char **argv) 1104{ 1105 const char *path; 1106 int ch; 1107 int cmd = -1; 1108 1109 path = bltinlookup("PATH", 1); 1110 1111 optind = optreset = 1; 1112 opterr = 0; 1113 while ((ch = getopt(argc, argv, "pvV")) != -1) { 1114 switch (ch) { 1115 case 'p': 1116 path = _PATH_STDPATH; 1117 break; 1118 case 'v': 1119 cmd = TYPECMD_SMALLV; 1120 break; 1121 case 'V': 1122 cmd = TYPECMD_BIGV; 1123 break; 1124 case '?': 1125 default: 1126 error("unknown option: -%c", optopt); 1127 } 1128 } 1129 argc -= optind; 1130 argv += optind; 1131 1132 if (cmd != -1) { 1133 if (argc != 1) 1134 error("wrong number of arguments"); 1135 return typecmd_impl(2, argv - 1, cmd, path); 1136 } 1137 if (argc != 0) 1138 error("commandcmd bad call"); 1139 1140 /* 1141 * Do nothing successfully if no command was specified; 1142 * ksh also does this. 1143 */ 1144 return 0; 1145} 1146 1147 1148/* 1149 * The return command. 1150 */ 1151 1152int 1153returncmd(int argc, char **argv) 1154{ 1155 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1156 1157 if (funcnest) { 1158 evalskip = SKIPFUNC; 1159 skipcount = 1; 1160 } else { 1161 /* skip the rest of the file */ 1162 evalskip = SKIPFILE; 1163 skipcount = 1; 1164 } 1165 return ret; 1166} 1167 1168 1169int 1170falsecmd(int argc __unused, char **argv __unused) 1171{ 1172 return 1; 1173} 1174 1175 1176int 1177truecmd(int argc __unused, char **argv __unused) 1178{ 1179 return 0; 1180} 1181 1182 1183int 1184execcmd(int argc, char **argv) 1185{ 1186 /* 1187 * Because we have historically not supported any options, 1188 * only treat "--" specially. 1189 */ 1190 if (argc > 1 && strcmp(argv[1], "--") == 0) 1191 argc--, argv++; 1192 if (argc > 1) { 1193 struct strlist *sp; 1194 1195 iflag = 0; /* exit on error */ 1196 mflag = 0; 1197 optschanged(); 1198 for (sp = cmdenviron; sp ; sp = sp->next) 1199 setvareq(sp->text, VEXPORT|VSTACK); 1200 shellexec(argv + 1, environment(), pathval(), 0); 1201 1202 } 1203 return 0; 1204} 1205 1206 1207int 1208timescmd(int argc __unused, char **argv __unused) 1209{ 1210 struct rusage ru; 1211 long shumins, shsmins, chumins, chsmins; 1212 double shusecs, shssecs, chusecs, chssecs; 1213 1214 if (getrusage(RUSAGE_SELF, &ru) < 0) 1215 return 1; 1216 shumins = ru.ru_utime.tv_sec / 60; 1217 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1218 shsmins = ru.ru_stime.tv_sec / 60; 1219 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1220 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1221 return 1; 1222 chumins = ru.ru_utime.tv_sec / 60; 1223 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1224 chsmins = ru.ru_stime.tv_sec / 60; 1225 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1226 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1227 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1228 return 0; 1229} 1230