eval.c revision 230625
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: stable/9/bin/sh/eval.c 230625 2012-01-27 21:22:07Z 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 int is_valid_fast_cmdsubst(union node *n); 98static void evalcommand(union node *, int, struct backcmd *); 99static void prehash(union node *); 100 101 102/* 103 * Called to reset things after an exception. 104 */ 105 106#ifdef mkinit 107INCLUDE "eval.h" 108 109RESET { 110 evalskip = 0; 111 loopnest = 0; 112 funcnest = 0; 113} 114#endif 115 116 117 118/* 119 * The eval command. 120 */ 121 122int 123evalcmd(int argc, char **argv) 124{ 125 char *p; 126 char *concat; 127 char **ap; 128 129 if (argc > 1) { 130 p = argv[1]; 131 if (argc > 2) { 132 STARTSTACKSTR(concat); 133 ap = argv + 2; 134 for (;;) { 135 STPUTS(p, concat); 136 if ((p = *ap++) == NULL) 137 break; 138 STPUTC(' ', concat); 139 } 140 STPUTC('\0', concat); 141 p = grabstackstr(concat); 142 } 143 evalstring(p, builtin_flags); 144 } else 145 exitstatus = 0; 146 return exitstatus; 147} 148 149 150/* 151 * Execute a command or commands contained in a string. 152 */ 153 154void 155evalstring(char *s, int flags) 156{ 157 union node *n; 158 struct stackmark smark; 159 int flags_exit; 160 int any; 161 162 flags_exit = flags & EV_EXIT; 163 flags &= ~EV_EXIT; 164 any = 0; 165 setstackmark(&smark); 166 setinputstring(s, 1); 167 while ((n = parsecmd(0)) != NEOF) { 168 if (n != NULL && !nflag) { 169 if (flags_exit && preadateof()) 170 evaltree(n, flags | EV_EXIT); 171 else 172 evaltree(n, flags); 173 any = 1; 174 } 175 popstackmark(&smark); 176 } 177 popfile(); 178 popstackmark(&smark); 179 if (!any) 180 exitstatus = 0; 181 if (flags_exit) 182 exraise(EXEXIT); 183} 184 185 186/* 187 * Evaluate a parse tree. The value is left in the global variable 188 * exitstatus. 189 */ 190 191void 192evaltree(union node *n, int flags) 193{ 194 int do_etest; 195 union node *next; 196 197 do_etest = 0; 198 if (n == NULL) { 199 TRACE(("evaltree(NULL) called\n")); 200 exitstatus = 0; 201 goto out; 202 } 203 do { 204 next = NULL; 205#ifndef NO_HISTORY 206 displayhist = 1; /* show history substitutions done with fc */ 207#endif 208 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 209 switch (n->type) { 210 case NSEMI: 211 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 212 if (evalskip) 213 goto out; 214 next = n->nbinary.ch2; 215 break; 216 case NAND: 217 evaltree(n->nbinary.ch1, EV_TESTED); 218 if (evalskip || exitstatus != 0) { 219 goto out; 220 } 221 next = n->nbinary.ch2; 222 break; 223 case NOR: 224 evaltree(n->nbinary.ch1, EV_TESTED); 225 if (evalskip || exitstatus == 0) 226 goto out; 227 next = n->nbinary.ch2; 228 break; 229 case NREDIR: 230 evalredir(n, flags); 231 break; 232 case NSUBSHELL: 233 evalsubshell(n, flags); 234 do_etest = !(flags & EV_TESTED); 235 break; 236 case NBACKGND: 237 evalsubshell(n, flags); 238 break; 239 case NIF: { 240 evaltree(n->nif.test, EV_TESTED); 241 if (evalskip) 242 goto out; 243 if (exitstatus == 0) 244 next = n->nif.ifpart; 245 else if (n->nif.elsepart) 246 next = n->nif.elsepart; 247 else 248 exitstatus = 0; 249 break; 250 } 251 case NWHILE: 252 case NUNTIL: 253 evalloop(n, flags & ~EV_EXIT); 254 break; 255 case NFOR: 256 evalfor(n, flags & ~EV_EXIT); 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 do_etest = !(flags & EV_TESTED); 273 break; 274 case NCMD: 275 evalcommand(n, flags, (struct backcmd *)NULL); 276 do_etest = !(flags & EV_TESTED); 277 break; 278 default: 279 out1fmt("Node type = %d\n", n->type); 280 flushout(&output); 281 break; 282 } 283 n = next; 284 } while (n != NULL); 285out: 286 if (pendingsigs) 287 dotrap(); 288 if (eflag && exitstatus != 0 && do_etest) 289 exitshell(exitstatus); 290 if (flags & EV_EXIT) 291 exraise(EXEXIT); 292} 293 294 295static void 296evalloop(union node *n, int flags) 297{ 298 int status; 299 300 loopnest++; 301 status = 0; 302 for (;;) { 303 evaltree(n->nbinary.ch1, EV_TESTED); 304 if (evalskip) { 305skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 306 evalskip = 0; 307 continue; 308 } 309 if (evalskip == SKIPBREAK && --skipcount <= 0) 310 evalskip = 0; 311 if (evalskip == SKIPFUNC || evalskip == SKIPFILE) 312 status = exitstatus; 313 break; 314 } 315 if (n->type == NWHILE) { 316 if (exitstatus != 0) 317 break; 318 } else { 319 if (exitstatus == 0) 320 break; 321 } 322 evaltree(n->nbinary.ch2, flags); 323 status = exitstatus; 324 if (evalskip) 325 goto skipping; 326 } 327 loopnest--; 328 exitstatus = status; 329} 330 331 332 333static void 334evalfor(union node *n, int flags) 335{ 336 struct arglist arglist; 337 union node *argp; 338 struct strlist *sp; 339 struct stackmark smark; 340 341 setstackmark(&smark); 342 arglist.lastp = &arglist.list; 343 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 344 oexitstatus = exitstatus; 345 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 346 if (evalskip) 347 goto out; 348 } 349 *arglist.lastp = NULL; 350 351 exitstatus = 0; 352 loopnest++; 353 for (sp = arglist.list ; sp ; sp = sp->next) { 354 setvar(n->nfor.var, sp->text, 0); 355 evaltree(n->nfor.body, flags); 356 if (evalskip) { 357 if (evalskip == SKIPCONT && --skipcount <= 0) { 358 evalskip = 0; 359 continue; 360 } 361 if (evalskip == SKIPBREAK && --skipcount <= 0) 362 evalskip = 0; 363 break; 364 } 365 } 366 loopnest--; 367out: 368 popstackmark(&smark); 369} 370 371 372 373static void 374evalcase(union node *n, int flags) 375{ 376 union node *cp; 377 union node *patp; 378 struct arglist arglist; 379 struct stackmark smark; 380 381 setstackmark(&smark); 382 arglist.lastp = &arglist.list; 383 oexitstatus = exitstatus; 384 exitstatus = 0; 385 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 386 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 387 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 388 if (casematch(patp, arglist.list->text)) { 389 while (cp->nclist.next && 390 cp->type == NCLISTFALLTHRU) { 391 if (evalskip != 0) 392 break; 393 evaltree(cp->nclist.body, 394 flags & ~EV_EXIT); 395 cp = cp->nclist.next; 396 } 397 if (evalskip == 0) { 398 evaltree(cp->nclist.body, flags); 399 } 400 goto out; 401 } 402 } 403 } 404out: 405 popstackmark(&smark); 406} 407 408 409 410/* 411 * Kick off a subshell to evaluate a tree. 412 */ 413 414static void 415evalsubshell(union node *n, int flags) 416{ 417 struct job *jp; 418 int backgnd = (n->type == NBACKGND); 419 420 oexitstatus = exitstatus; 421 expredir(n->nredir.redirect); 422 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 423 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 424 if (backgnd) 425 flags &=~ EV_TESTED; 426 redirect(n->nredir.redirect, 0); 427 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 428 } else if (! backgnd) { 429 INTOFF; 430 exitstatus = waitforjob(jp, (int *)NULL); 431 INTON; 432 } else 433 exitstatus = 0; 434} 435 436 437/* 438 * Evaluate a redirected compound command. 439 */ 440 441static void 442evalredir(union node *n, int flags) 443{ 444 struct jmploc jmploc; 445 struct jmploc *savehandler; 446 volatile int in_redirect = 1; 447 448 oexitstatus = exitstatus; 449 expredir(n->nredir.redirect); 450 savehandler = handler; 451 if (setjmp(jmploc.loc)) { 452 int e; 453 454 handler = savehandler; 455 e = exception; 456 popredir(); 457 if (e == EXERROR || e == EXEXEC) { 458 if (in_redirect) { 459 exitstatus = 2; 460 return; 461 } 462 } 463 longjmp(handler->loc, 1); 464 } else { 465 INTOFF; 466 handler = &jmploc; 467 redirect(n->nredir.redirect, REDIR_PUSH); 468 in_redirect = 0; 469 INTON; 470 evaltree(n->nredir.n, flags); 471 } 472 INTOFF; 473 handler = savehandler; 474 popredir(); 475 INTON; 476} 477 478 479/* 480 * Compute the names of the files in a redirection list. 481 */ 482 483static void 484expredir(union node *n) 485{ 486 union node *redir; 487 488 for (redir = n ; redir ; redir = redir->nfile.next) { 489 struct arglist fn; 490 fn.lastp = &fn.list; 491 switch (redir->type) { 492 case NFROM: 493 case NTO: 494 case NFROMTO: 495 case NAPPEND: 496 case NCLOBBER: 497 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 498 redir->nfile.expfname = fn.list->text; 499 break; 500 case NFROMFD: 501 case NTOFD: 502 if (redir->ndup.vname) { 503 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 504 fixredir(redir, fn.list->text, 1); 505 } 506 break; 507 } 508 } 509} 510 511 512 513/* 514 * Evaluate a pipeline. All the processes in the pipeline are children 515 * of the process creating the pipeline. (This differs from some versions 516 * of the shell, which make the last process in a pipeline the parent 517 * of all the rest.) 518 */ 519 520static void 521evalpipe(union node *n) 522{ 523 struct job *jp; 524 struct nodelist *lp; 525 int pipelen; 526 int prevfd; 527 int pip[2]; 528 529 TRACE(("evalpipe(%p) called\n", (void *)n)); 530 pipelen = 0; 531 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 532 pipelen++; 533 INTOFF; 534 jp = makejob(n, pipelen); 535 prevfd = -1; 536 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 537 prehash(lp->n); 538 pip[1] = -1; 539 if (lp->next) { 540 if (pipe(pip) < 0) { 541 close(prevfd); 542 error("Pipe call failed: %s", strerror(errno)); 543 } 544 } 545 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 546 INTON; 547 if (prevfd > 0) { 548 dup2(prevfd, 0); 549 close(prevfd); 550 } 551 if (pip[1] >= 0) { 552 if (!(prevfd >= 0 && pip[0] == 0)) 553 close(pip[0]); 554 if (pip[1] != 1) { 555 dup2(pip[1], 1); 556 close(pip[1]); 557 } 558 } 559 evaltree(lp->n, EV_EXIT); 560 } 561 if (prevfd >= 0) 562 close(prevfd); 563 prevfd = pip[0]; 564 if (pip[1] != -1) 565 close(pip[1]); 566 } 567 INTON; 568 if (n->npipe.backgnd == 0) { 569 INTOFF; 570 exitstatus = waitforjob(jp, (int *)NULL); 571 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 572 INTON; 573 } else 574 exitstatus = 0; 575} 576 577 578 579static int 580is_valid_fast_cmdsubst(union node *n) 581{ 582 583 return (n->type == NCMD); 584} 585 586/* 587 * Execute a command inside back quotes. If it's a builtin command, we 588 * want to save its output in a block obtained from malloc. Otherwise 589 * we fork off a subprocess and get the output of the command via a pipe. 590 * Should be called with interrupts off. 591 */ 592 593void 594evalbackcmd(union node *n, struct backcmd *result) 595{ 596 int pip[2]; 597 struct job *jp; 598 struct stackmark smark; /* unnecessary */ 599 struct jmploc jmploc; 600 struct jmploc *savehandler; 601 struct localvar *savelocalvars; 602 603 setstackmark(&smark); 604 result->fd = -1; 605 result->buf = NULL; 606 result->nleft = 0; 607 result->jp = NULL; 608 if (n == NULL) { 609 exitstatus = 0; 610 goto out; 611 } 612 if (is_valid_fast_cmdsubst(n)) { 613 exitstatus = oexitstatus; 614 savelocalvars = localvars; 615 localvars = NULL; 616 forcelocal++; 617 savehandler = handler; 618 if (setjmp(jmploc.loc)) { 619 if (exception == EXERROR || exception == EXEXEC) 620 exitstatus = 2; 621 else if (exception != 0) { 622 handler = savehandler; 623 forcelocal--; 624 poplocalvars(); 625 localvars = savelocalvars; 626 longjmp(handler->loc, 1); 627 } 628 } else { 629 handler = &jmploc; 630 evalcommand(n, EV_BACKCMD, result); 631 } 632 handler = savehandler; 633 forcelocal--; 634 poplocalvars(); 635 localvars = savelocalvars; 636 } else { 637 exitstatus = 0; 638 if (pipe(pip) < 0) 639 error("Pipe call failed: %s", strerror(errno)); 640 jp = makejob(n, 1); 641 if (forkshell(jp, n, FORK_NOJOB) == 0) { 642 FORCEINTON; 643 close(pip[0]); 644 if (pip[1] != 1) { 645 dup2(pip[1], 1); 646 close(pip[1]); 647 } 648 evaltree(n, EV_EXIT); 649 } 650 close(pip[1]); 651 result->fd = pip[0]; 652 result->jp = jp; 653 } 654out: 655 popstackmark(&smark); 656 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 657 result->fd, result->buf, result->nleft, result->jp)); 658} 659 660/* 661 * Check if a builtin can safely be executed in the same process, 662 * even though it should be in a subshell (command substitution). 663 * Note that jobid, jobs, times and trap can show information not 664 * available in a child process; this is deliberate. 665 * The arguments should already have been expanded. 666 */ 667static int 668safe_builtin(int idx, int argc, char **argv) 669{ 670 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 671 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 672 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 673 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 674 idx == TYPECMD) 675 return (1); 676 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 677 idx == UMASKCMD) 678 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 679 if (idx == SETCMD) 680 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 681 argv[1][0] == '+') && argv[1][1] == 'o' && 682 argv[1][2] == '\0')); 683 return (0); 684} 685 686/* 687 * Execute a simple command. 688 * Note: This may or may not return if (flags & EV_EXIT). 689 */ 690 691static void 692evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 693{ 694 struct stackmark smark; 695 union node *argp; 696 struct arglist arglist; 697 struct arglist varlist; 698 char **argv; 699 int argc; 700 char **envp; 701 int varflag; 702 struct strlist *sp; 703 int mode; 704 int pip[2]; 705 struct cmdentry cmdentry; 706 struct job *jp; 707 struct jmploc jmploc; 708 struct jmploc *savehandler; 709 char *savecmdname; 710 struct shparam saveparam; 711 struct localvar *savelocalvars; 712 struct parsefile *savetopfile; 713 volatile int e; 714 char *lastarg; 715 int realstatus; 716 int do_clearcmdentry; 717 const char *path = pathval(); 718 719 /* First expand the arguments. */ 720 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 721 setstackmark(&smark); 722 arglist.lastp = &arglist.list; 723 varlist.lastp = &varlist.list; 724 varflag = 1; 725 jp = NULL; 726 do_clearcmdentry = 0; 727 oexitstatus = exitstatus; 728 exitstatus = 0; 729 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 730 if (varflag && isassignment(argp->narg.text)) { 731 expandarg(argp, &varlist, EXP_VARTILDE); 732 continue; 733 } 734 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 735 varflag = 0; 736 } 737 *arglist.lastp = NULL; 738 *varlist.lastp = NULL; 739 expredir(cmd->ncmd.redirect); 740 argc = 0; 741 for (sp = arglist.list ; sp ; sp = sp->next) 742 argc++; 743 /* Add one slot at the beginning for tryexec(). */ 744 argv = stalloc(sizeof (char *) * (argc + 2)); 745 argv++; 746 747 for (sp = arglist.list ; sp ; sp = sp->next) { 748 TRACE(("evalcommand arg: %s\n", sp->text)); 749 *argv++ = sp->text; 750 } 751 *argv = NULL; 752 lastarg = NULL; 753 if (iflag && funcnest == 0 && argc > 0) 754 lastarg = argv[-1]; 755 argv -= argc; 756 757 /* Print the command if xflag is set. */ 758 if (xflag) { 759 char sep = 0; 760 const char *p, *ps4; 761 ps4 = expandstr(ps4val()); 762 out2str(ps4 != NULL ? ps4 : ps4val()); 763 for (sp = varlist.list ; sp ; sp = sp->next) { 764 if (sep != 0) 765 out2c(' '); 766 p = strchr(sp->text, '='); 767 if (p != NULL) { 768 p++; 769 outbin(sp->text, p - sp->text, out2); 770 out2qstr(p); 771 } else 772 out2qstr(sp->text); 773 sep = ' '; 774 } 775 for (sp = arglist.list ; sp ; sp = sp->next) { 776 if (sep != 0) 777 out2c(' '); 778 /* Disambiguate command looking like assignment. */ 779 if (sp == arglist.list && 780 strchr(sp->text, '=') != NULL && 781 strchr(sp->text, '\'') == NULL) { 782 out2c('\''); 783 out2str(sp->text); 784 out2c('\''); 785 } else 786 out2qstr(sp->text); 787 sep = ' '; 788 } 789 out2c('\n'); 790 flushout(&errout); 791 } 792 793 /* Now locate the command. */ 794 if (argc == 0) { 795 /* Variable assignment(s) without command */ 796 cmdentry.cmdtype = CMDBUILTIN; 797 cmdentry.u.index = BLTINCMD; 798 cmdentry.special = 0; 799 } else { 800 static const char PATH[] = "PATH="; 801 int cmd_flags = 0, bltinonly = 0; 802 803 /* 804 * Modify the command lookup path, if a PATH= assignment 805 * is present 806 */ 807 for (sp = varlist.list ; sp ; sp = sp->next) 808 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 809 path = sp->text + sizeof(PATH) - 1; 810 /* 811 * On `PATH=... command`, we need to make 812 * sure that the command isn't using the 813 * non-updated hash table of the outer PATH 814 * setting and we need to make sure that 815 * the hash table isn't filled with items 816 * from the temporary setting. 817 * 818 * It would be better to forbit using and 819 * updating the table while this command 820 * runs, by the command finding mechanism 821 * is heavily integrated with hash handling, 822 * so we just delete the hash before and after 823 * the command runs. Partly deleting like 824 * changepatch() does doesn't seem worth the 825 * bookinging effort, since most such runs add 826 * directories in front of the new PATH. 827 */ 828 clearcmdentry(); 829 do_clearcmdentry = 1; 830 } 831 832 for (;;) { 833 if (bltinonly) { 834 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 835 if (cmdentry.u.index < 0) { 836 cmdentry.u.index = BLTINCMD; 837 argv--; 838 argc++; 839 break; 840 } 841 } else 842 find_command(argv[0], &cmdentry, cmd_flags, path); 843 /* implement the bltin and command builtins here */ 844 if (cmdentry.cmdtype != CMDBUILTIN) 845 break; 846 if (cmdentry.u.index == BLTINCMD) { 847 if (argc == 1) 848 break; 849 argv++; 850 argc--; 851 bltinonly = 1; 852 } else if (cmdentry.u.index == COMMANDCMD) { 853 if (argc == 1) 854 break; 855 if (!strcmp(argv[1], "-p")) { 856 if (argc == 2) 857 break; 858 if (argv[2][0] == '-') { 859 if (strcmp(argv[2], "--")) 860 break; 861 if (argc == 3) 862 break; 863 argv += 3; 864 argc -= 3; 865 } else { 866 argv += 2; 867 argc -= 2; 868 } 869 path = _PATH_STDPATH; 870 clearcmdentry(); 871 do_clearcmdentry = 1; 872 } else if (!strcmp(argv[1], "--")) { 873 if (argc == 2) 874 break; 875 argv += 2; 876 argc -= 2; 877 } else if (argv[1][0] == '-') 878 break; 879 else { 880 argv++; 881 argc--; 882 } 883 cmd_flags |= DO_NOFUNC; 884 bltinonly = 0; 885 } else 886 break; 887 } 888 /* 889 * Special builtins lose their special properties when 890 * called via 'command'. 891 */ 892 if (cmd_flags & DO_NOFUNC) 893 cmdentry.special = 0; 894 } 895 896 /* Fork off a child process if necessary. */ 897 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 898 && ((flags & EV_EXIT) == 0 || have_traps())) 899 || ((flags & EV_BACKCMD) != 0 900 && (cmdentry.cmdtype != CMDBUILTIN || 901 !safe_builtin(cmdentry.u.index, argc, argv)))) { 902 jp = makejob(cmd, 1); 903 mode = FORK_FG; 904 if (flags & EV_BACKCMD) { 905 mode = FORK_NOJOB; 906 if (pipe(pip) < 0) 907 error("Pipe call failed: %s", strerror(errno)); 908 } 909 if (forkshell(jp, cmd, mode) != 0) 910 goto parent; /* at end of routine */ 911 if (flags & EV_BACKCMD) { 912 FORCEINTON; 913 close(pip[0]); 914 if (pip[1] != 1) { 915 dup2(pip[1], 1); 916 close(pip[1]); 917 } 918 flags &= ~EV_BACKCMD; 919 } 920 flags |= EV_EXIT; 921 } 922 923 /* This is the child process if a fork occurred. */ 924 /* Execute the command. */ 925 if (cmdentry.cmdtype == CMDFUNCTION) { 926#ifdef DEBUG 927 trputs("Shell function: "); trargs(argv); 928#endif 929 saveparam = shellparam; 930 shellparam.malloc = 0; 931 shellparam.reset = 1; 932 shellparam.nparam = argc - 1; 933 shellparam.p = argv + 1; 934 shellparam.optnext = NULL; 935 INTOFF; 936 savelocalvars = localvars; 937 localvars = NULL; 938 reffunc(cmdentry.u.func); 939 savehandler = handler; 940 if (setjmp(jmploc.loc)) { 941 freeparam(&shellparam); 942 shellparam = saveparam; 943 popredir(); 944 unreffunc(cmdentry.u.func); 945 poplocalvars(); 946 localvars = savelocalvars; 947 funcnest--; 948 handler = savehandler; 949 longjmp(handler->loc, 1); 950 } 951 handler = &jmploc; 952 funcnest++; 953 redirect(cmd->ncmd.redirect, REDIR_PUSH); 954 INTON; 955 for (sp = varlist.list ; sp ; sp = sp->next) 956 mklocal(sp->text); 957 exitstatus = oexitstatus; 958 evaltree(getfuncnode(cmdentry.u.func), 959 flags & (EV_TESTED | EV_EXIT)); 960 INTOFF; 961 unreffunc(cmdentry.u.func); 962 poplocalvars(); 963 localvars = savelocalvars; 964 freeparam(&shellparam); 965 shellparam = saveparam; 966 handler = savehandler; 967 funcnest--; 968 popredir(); 969 INTON; 970 if (evalskip == SKIPFUNC) { 971 evalskip = 0; 972 skipcount = 0; 973 } 974 if (jp) 975 exitshell(exitstatus); 976 } else if (cmdentry.cmdtype == CMDBUILTIN) { 977#ifdef DEBUG 978 trputs("builtin command: "); trargs(argv); 979#endif 980 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 981 if (flags == EV_BACKCMD) { 982 memout.nleft = 0; 983 memout.nextc = memout.buf; 984 memout.bufsize = 64; 985 mode |= REDIR_BACKQ; 986 } 987 savecmdname = commandname; 988 savetopfile = getcurrentfile(); 989 cmdenviron = varlist.list; 990 e = -1; 991 savehandler = handler; 992 if (setjmp(jmploc.loc)) { 993 e = exception; 994 if (e == EXINT) 995 exitstatus = SIGINT+128; 996 else if (e != EXEXIT) 997 exitstatus = 2; 998 goto cmddone; 999 } 1000 handler = &jmploc; 1001 redirect(cmd->ncmd.redirect, mode); 1002 /* 1003 * If there is no command word, redirection errors should 1004 * not be fatal but assignment errors should. 1005 */ 1006 if (argc == 0) 1007 cmdentry.special = 1; 1008 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1009 if (argc > 0) 1010 bltinsetlocale(); 1011 commandname = argv[0]; 1012 argptr = argv + 1; 1013 nextopt_optptr = NULL; /* initialize nextopt */ 1014 builtin_flags = flags; 1015 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1016 flushall(); 1017cmddone: 1018 if (argc > 0) 1019 bltinunsetlocale(); 1020 cmdenviron = NULL; 1021 out1 = &output; 1022 out2 = &errout; 1023 freestdout(); 1024 handler = savehandler; 1025 commandname = savecmdname; 1026 if (jp) 1027 exitshell(exitstatus); 1028 if (flags == EV_BACKCMD) { 1029 backcmd->buf = memout.buf; 1030 backcmd->nleft = memout.nextc - memout.buf; 1031 memout.buf = NULL; 1032 } 1033 if (cmdentry.u.index != EXECCMD) 1034 popredir(); 1035 if (e != -1) { 1036 if ((e != EXERROR && e != EXEXEC) 1037 || cmdentry.special) 1038 exraise(e); 1039 popfilesupto(savetopfile); 1040 if (flags != EV_BACKCMD) 1041 FORCEINTON; 1042 } 1043 } else { 1044#ifdef DEBUG 1045 trputs("normal command: "); trargs(argv); 1046#endif 1047 redirect(cmd->ncmd.redirect, 0); 1048 for (sp = varlist.list ; sp ; sp = sp->next) 1049 setvareq(sp->text, VEXPORT|VSTACK); 1050 envp = environment(); 1051 shellexec(argv, envp, path, cmdentry.u.index); 1052 /*NOTREACHED*/ 1053 } 1054 goto out; 1055 1056parent: /* parent process gets here (if we forked) */ 1057 if (mode == FORK_FG) { /* argument to fork */ 1058 INTOFF; 1059 exitstatus = waitforjob(jp, &realstatus); 1060 INTON; 1061 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1062 evalskip = SKIPBREAK; 1063 skipcount = loopnest; 1064 } 1065 } else if (mode == FORK_NOJOB) { 1066 backcmd->fd = pip[0]; 1067 close(pip[1]); 1068 backcmd->jp = jp; 1069 } 1070 1071out: 1072 if (lastarg) 1073 setvar("_", lastarg, 0); 1074 if (do_clearcmdentry) 1075 clearcmdentry(); 1076 popstackmark(&smark); 1077} 1078 1079 1080 1081/* 1082 * Search for a command. This is called before we fork so that the 1083 * location of the command will be available in the parent as well as 1084 * the child. The check for "goodname" is an overly conservative 1085 * check that the name will not be subject to expansion. 1086 */ 1087 1088static void 1089prehash(union node *n) 1090{ 1091 struct cmdentry entry; 1092 1093 if (n && n->type == NCMD && n->ncmd.args) 1094 if (goodname(n->ncmd.args->narg.text)) 1095 find_command(n->ncmd.args->narg.text, &entry, 0, 1096 pathval()); 1097} 1098 1099 1100 1101/* 1102 * Builtin commands. Builtin commands whose functions are closely 1103 * tied to evaluation are implemented here. 1104 */ 1105 1106/* 1107 * No command given, a bltin command with no arguments, or a bltin command 1108 * with an invalid name. 1109 */ 1110 1111int 1112bltincmd(int argc, char **argv) 1113{ 1114 if (argc > 1) { 1115 out2fmt_flush("%s: not found\n", argv[1]); 1116 return 127; 1117 } 1118 /* 1119 * Preserve exitstatus of a previous possible redirection 1120 * as POSIX mandates 1121 */ 1122 return exitstatus; 1123} 1124 1125 1126/* 1127 * Handle break and continue commands. Break, continue, and return are 1128 * all handled by setting the evalskip flag. The evaluation routines 1129 * above all check this flag, and if it is set they start skipping 1130 * commands rather than executing them. The variable skipcount is 1131 * the number of loops to break/continue, or the number of function 1132 * levels to return. (The latter is always 1.) It should probably 1133 * be an error to break out of more loops than exist, but it isn't 1134 * in the standard shell so we don't make it one here. 1135 */ 1136 1137int 1138breakcmd(int argc, char **argv) 1139{ 1140 int n = argc > 1 ? number(argv[1]) : 1; 1141 1142 if (n > loopnest) 1143 n = loopnest; 1144 if (n > 0) { 1145 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1146 skipcount = n; 1147 } 1148 return 0; 1149} 1150 1151/* 1152 * The `command' command. 1153 */ 1154int 1155commandcmd(int argc, char **argv) 1156{ 1157 const char *path; 1158 int ch; 1159 int cmd = -1; 1160 1161 path = bltinlookup("PATH", 1); 1162 1163 optind = optreset = 1; 1164 opterr = 0; 1165 while ((ch = getopt(argc, argv, "pvV")) != -1) { 1166 switch (ch) { 1167 case 'p': 1168 path = _PATH_STDPATH; 1169 break; 1170 case 'v': 1171 cmd = TYPECMD_SMALLV; 1172 break; 1173 case 'V': 1174 cmd = TYPECMD_BIGV; 1175 break; 1176 case '?': 1177 default: 1178 error("unknown option: -%c", optopt); 1179 } 1180 } 1181 argc -= optind; 1182 argv += optind; 1183 1184 if (cmd != -1) { 1185 if (argc != 1) 1186 error("wrong number of arguments"); 1187 return typecmd_impl(2, argv - 1, cmd, path); 1188 } 1189 if (argc != 0) 1190 error("commandcmd bad call"); 1191 1192 /* 1193 * Do nothing successfully if no command was specified; 1194 * ksh also does this. 1195 */ 1196 return 0; 1197} 1198 1199 1200/* 1201 * The return command. 1202 */ 1203 1204int 1205returncmd(int argc, char **argv) 1206{ 1207 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1208 1209 if (funcnest) { 1210 evalskip = SKIPFUNC; 1211 skipcount = 1; 1212 } else { 1213 /* skip the rest of the file */ 1214 evalskip = SKIPFILE; 1215 skipcount = 1; 1216 } 1217 return ret; 1218} 1219 1220 1221int 1222falsecmd(int argc __unused, char **argv __unused) 1223{ 1224 return 1; 1225} 1226 1227 1228int 1229truecmd(int argc __unused, char **argv __unused) 1230{ 1231 return 0; 1232} 1233 1234 1235int 1236execcmd(int argc, char **argv) 1237{ 1238 /* 1239 * Because we have historically not supported any options, 1240 * only treat "--" specially. 1241 */ 1242 if (argc > 1 && strcmp(argv[1], "--") == 0) 1243 argc--, argv++; 1244 if (argc > 1) { 1245 struct strlist *sp; 1246 1247 iflag = 0; /* exit on error */ 1248 mflag = 0; 1249 optschanged(); 1250 for (sp = cmdenviron; sp ; sp = sp->next) 1251 setvareq(sp->text, VEXPORT|VSTACK); 1252 shellexec(argv + 1, environment(), pathval(), 0); 1253 1254 } 1255 return 0; 1256} 1257 1258 1259int 1260timescmd(int argc __unused, char **argv __unused) 1261{ 1262 struct rusage ru; 1263 long shumins, shsmins, chumins, chsmins; 1264 double shusecs, shssecs, chusecs, chssecs; 1265 1266 if (getrusage(RUSAGE_SELF, &ru) < 0) 1267 return 1; 1268 shumins = ru.ru_utime.tv_sec / 60; 1269 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1270 shsmins = ru.ru_stime.tv_sec / 60; 1271 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1272 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1273 return 1; 1274 chumins = ru.ru_utime.tv_sec / 60; 1275 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1276 chsmins = ru.ru_stime.tv_sec / 60; 1277 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1278 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1279 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1280 return 0; 1281} 1282