1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. 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 35 static char sccsid[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95"; 36 #endif 37 #endif /* not lint */ 38 #include <sys/cdefs.h> 39 #include <paths.h> 40 #include <signal.h> 41 #include <stdlib.h> 42 #include <unistd.h> 43 #include <sys/resource.h> 44 #include <errno.h> 45 46 /* 47 * Evaluate a command. 48 */ 49 50 #include "shell.h" 51 #include "nodes.h" 52 #include "syntax.h" 53 #include "expand.h" 54 #include "parser.h" 55 #include "jobs.h" 56 #include "eval.h" 57 #include "builtins.h" 58 #include "options.h" 59 #include "exec.h" 60 #include "redir.h" 61 #include "input.h" 62 #include "output.h" 63 #include "trap.h" 64 #include "var.h" 65 #include "memalloc.h" 66 #include "error.h" 67 #include "show.h" 68 #include "mystring.h" 69 #ifndef NO_HISTORY 70 #include "myhistedit.h" 71 #endif 72 73 74 int evalskip; /* set if we are skipping commands */ 75 int skipcount; /* number of levels to skip */ 76 static int loopnest; /* current loop nesting level */ 77 int funcnest; /* depth of function calls */ 78 static int builtin_flags; /* evalcommand flags for builtins */ 79 80 81 char *commandname; 82 struct arglist *cmdenviron; 83 int exitstatus; /* exit status of last command */ 84 int oexitstatus; /* saved exit status */ 85 86 87 static void evalloop(union node *, int); 88 static void evalfor(union node *, int); 89 static union node *evalcase(union node *); 90 static void evalsubshell(union node *, int); 91 static void evalredir(union node *, int); 92 static void exphere(union node *, struct arglist *); 93 static void expredir(union node *); 94 static void evalpipe(union node *); 95 static int is_valid_fast_cmdsubst(union node *n); 96 static void evalcommand(union node *, int, struct backcmd *); 97 static void prehash(union node *); 98 99 100 /* 101 * Called to reset things after an exception. 102 */ 103 104 void 105 reseteval(void) 106 { 107 evalskip = 0; 108 loopnest = 0; 109 } 110 111 112 /* 113 * The eval command. 114 */ 115 116 int 117 evalcmd(int argc, char **argv) 118 { 119 char *p; 120 char *concat; 121 char **ap; 122 123 if (argc > 1) { 124 p = argv[1]; 125 if (argc > 2) { 126 STARTSTACKSTR(concat); 127 ap = argv + 2; 128 for (;;) { 129 STPUTS(p, concat); 130 if ((p = *ap++) == NULL) 131 break; 132 STPUTC(' ', concat); 133 } 134 STPUTC('\0', concat); 135 p = grabstackstr(concat); 136 } 137 evalstring(p, builtin_flags); 138 } else 139 exitstatus = 0; 140 return exitstatus; 141 } 142 143 144 /* 145 * Execute a command or commands contained in a string. 146 */ 147 148 void 149 evalstring(const char *s, int flags) 150 { 151 union node *n; 152 struct stackmark smark; 153 int flags_exit; 154 int any; 155 156 flags_exit = flags & EV_EXIT; 157 flags &= ~EV_EXIT; 158 any = 0; 159 setstackmark(&smark); 160 setinputstring(s, 1); 161 while ((n = parsecmd(0)) != NEOF) { 162 if (n != NULL && !nflag) { 163 if (flags_exit && preadateof()) 164 evaltree(n, flags | EV_EXIT); 165 else 166 evaltree(n, flags); 167 any = 1; 168 if (evalskip) 169 break; 170 } 171 popstackmark(&smark); 172 setstackmark(&smark); 173 } 174 popfile(); 175 popstackmark(&smark); 176 if (!any) 177 exitstatus = 0; 178 if (flags_exit) 179 exraise(EXEXIT); 180 } 181 182 183 /* 184 * Evaluate a parse tree. The value is left in the global variable 185 * exitstatus. 186 */ 187 188 void 189 evaltree(union node *n, int flags) 190 { 191 int do_etest; 192 union node *next; 193 struct stackmark smark; 194 195 setstackmark(&smark); 196 do_etest = 0; 197 if (n == NULL) { 198 TRACE(("evaltree(NULL) called\n")); 199 exitstatus = 0; 200 goto out; 201 } 202 do { 203 next = NULL; 204 #ifndef NO_HISTORY 205 displayhist = 1; /* show history substitutions done with fc */ 206 #endif 207 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 208 switch (n->type) { 209 case NSEMI: 210 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 211 if (evalskip) 212 goto out; 213 next = n->nbinary.ch2; 214 break; 215 case NAND: 216 evaltree(n->nbinary.ch1, EV_TESTED); 217 if (evalskip || exitstatus != 0) { 218 goto out; 219 } 220 next = n->nbinary.ch2; 221 break; 222 case NOR: 223 evaltree(n->nbinary.ch1, EV_TESTED); 224 if (evalskip || exitstatus == 0) 225 goto out; 226 next = n->nbinary.ch2; 227 break; 228 case NREDIR: 229 evalredir(n, flags); 230 break; 231 case NSUBSHELL: 232 evalsubshell(n, flags); 233 do_etest = !(flags & EV_TESTED); 234 break; 235 case NBACKGND: 236 evalsubshell(n, flags); 237 break; 238 case NIF: { 239 evaltree(n->nif.test, EV_TESTED); 240 if (evalskip) 241 goto out; 242 if (exitstatus == 0) 243 next = n->nif.ifpart; 244 else if (n->nif.elsepart) 245 next = n->nif.elsepart; 246 else 247 exitstatus = 0; 248 break; 249 } 250 case NWHILE: 251 case NUNTIL: 252 evalloop(n, flags & ~EV_EXIT); 253 break; 254 case NFOR: 255 evalfor(n, flags & ~EV_EXIT); 256 break; 257 case NCASE: 258 next = evalcase(n); 259 break; 260 case NCLIST: 261 next = n->nclist.body; 262 break; 263 case NCLISTFALLTHRU: 264 if (n->nclist.body) { 265 evaltree(n->nclist.body, flags & ~EV_EXIT); 266 if (evalskip) 267 goto out; 268 } 269 next = n->nclist.next; 270 break; 271 case NDEFUN: 272 defun(n->narg.text, n->narg.next); 273 exitstatus = 0; 274 break; 275 case NNOT: 276 evaltree(n->nnot.com, EV_TESTED); 277 if (evalskip) 278 goto out; 279 exitstatus = !exitstatus; 280 break; 281 282 case NPIPE: 283 evalpipe(n); 284 do_etest = !(flags & EV_TESTED); 285 break; 286 case NCMD: 287 evalcommand(n, flags, (struct backcmd *)NULL); 288 do_etest = !(flags & EV_TESTED); 289 break; 290 default: 291 out1fmt("Node type = %d\n", n->type); 292 flushout(&output); 293 break; 294 } 295 n = next; 296 popstackmark(&smark); 297 setstackmark(&smark); 298 } while (n != NULL); 299 out: 300 popstackmark(&smark); 301 if (pendingsig) 302 dotrap(); 303 if (eflag && exitstatus != 0 && do_etest) 304 exitshell(exitstatus); 305 if (flags & EV_EXIT) 306 exraise(EXEXIT); 307 } 308 309 310 static void 311 evalloop(union node *n, int flags) 312 { 313 int status; 314 315 loopnest++; 316 status = 0; 317 for (;;) { 318 if (!evalskip) 319 evaltree(n->nbinary.ch1, EV_TESTED); 320 if (evalskip) { 321 if (evalskip == SKIPCONT && --skipcount <= 0) { 322 evalskip = 0; 323 continue; 324 } 325 if (evalskip == SKIPBREAK && --skipcount <= 0) 326 evalskip = 0; 327 if (evalskip == SKIPRETURN) 328 status = exitstatus; 329 break; 330 } 331 if (n->type == NWHILE) { 332 if (exitstatus != 0) 333 break; 334 } else { 335 if (exitstatus == 0) 336 break; 337 } 338 evaltree(n->nbinary.ch2, flags); 339 status = exitstatus; 340 } 341 loopnest--; 342 exitstatus = status; 343 } 344 345 346 347 static void 348 evalfor(union node *n, int flags) 349 { 350 struct arglist arglist; 351 union node *argp; 352 int i; 353 int status; 354 355 emptyarglist(&arglist); 356 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 357 oexitstatus = exitstatus; 358 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 359 } 360 361 loopnest++; 362 status = 0; 363 for (i = 0; i < arglist.count; i++) { 364 setvar(n->nfor.var, arglist.args[i], 0); 365 evaltree(n->nfor.body, flags); 366 status = exitstatus; 367 if (evalskip) { 368 if (evalskip == SKIPCONT && --skipcount <= 0) { 369 evalskip = 0; 370 continue; 371 } 372 if (evalskip == SKIPBREAK && --skipcount <= 0) 373 evalskip = 0; 374 break; 375 } 376 } 377 loopnest--; 378 exitstatus = status; 379 } 380 381 382 /* 383 * Evaluate a case statement, returning the selected tree. 384 * 385 * The exit status needs care to get right. 386 */ 387 388 static union node * 389 evalcase(union node *n) 390 { 391 union node *cp; 392 union node *patp; 393 struct arglist arglist; 394 395 emptyarglist(&arglist); 396 oexitstatus = exitstatus; 397 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 398 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) { 399 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 400 if (casematch(patp, arglist.args[0])) { 401 while (cp->nclist.next && 402 cp->type == NCLISTFALLTHRU && 403 cp->nclist.body == NULL) 404 cp = cp->nclist.next; 405 if (cp->nclist.next && 406 cp->type == NCLISTFALLTHRU) 407 return (cp); 408 if (cp->nclist.body == NULL) 409 exitstatus = 0; 410 return (cp->nclist.body); 411 } 412 } 413 } 414 exitstatus = 0; 415 return (NULL); 416 } 417 418 419 420 /* 421 * Kick off a subshell to evaluate a tree. 422 */ 423 424 static void 425 evalsubshell(union node *n, int flags) 426 { 427 struct job *jp; 428 int backgnd = (n->type == NBACKGND); 429 430 oexitstatus = exitstatus; 431 expredir(n->nredir.redirect); 432 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 433 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 434 if (backgnd) 435 flags &=~ EV_TESTED; 436 redirect(n->nredir.redirect, 0); 437 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 438 } else if (! backgnd) { 439 INTOFF; 440 exitstatus = waitforjob(jp, (int *)NULL); 441 INTON; 442 } else 443 exitstatus = 0; 444 } 445 446 447 /* 448 * Evaluate a redirected compound command. 449 */ 450 451 static void 452 evalredir(union node *n, int flags) 453 { 454 struct jmploc jmploc; 455 struct jmploc *savehandler; 456 volatile int in_redirect = 1; 457 458 oexitstatus = exitstatus; 459 expredir(n->nredir.redirect); 460 savehandler = handler; 461 if (setjmp(jmploc.loc)) { 462 int e; 463 464 handler = savehandler; 465 e = exception; 466 popredir(); 467 if (e == EXERROR && in_redirect) { 468 FORCEINTON; 469 return; 470 } 471 longjmp(handler->loc, 1); 472 } else { 473 INTOFF; 474 handler = &jmploc; 475 redirect(n->nredir.redirect, REDIR_PUSH); 476 in_redirect = 0; 477 INTON; 478 evaltree(n->nredir.n, flags); 479 } 480 INTOFF; 481 handler = savehandler; 482 popredir(); 483 INTON; 484 } 485 486 487 static void 488 exphere(union node *redir, struct arglist *fn) 489 { 490 struct jmploc jmploc; 491 struct jmploc *savehandler; 492 struct localvar *savelocalvars; 493 int need_longjmp = 0; 494 unsigned char saveoptreset; 495 496 redir->nhere.expdoc = ""; 497 savelocalvars = localvars; 498 localvars = NULL; 499 saveoptreset = shellparam.reset; 500 forcelocal++; 501 savehandler = handler; 502 if (setjmp(jmploc.loc)) 503 need_longjmp = exception != EXERROR; 504 else { 505 handler = &jmploc; 506 expandarg(redir->nhere.doc, fn, 0); 507 redir->nhere.expdoc = fn->args[0]; 508 INTOFF; 509 } 510 handler = savehandler; 511 forcelocal--; 512 poplocalvars(); 513 localvars = savelocalvars; 514 shellparam.reset = saveoptreset; 515 if (need_longjmp) 516 longjmp(handler->loc, 1); 517 INTON; 518 } 519 520 521 /* 522 * Compute the names of the files in a redirection list. 523 */ 524 525 static void 526 expredir(union node *n) 527 { 528 union node *redir; 529 530 for (redir = n ; redir ; redir = redir->nfile.next) { 531 struct arglist fn; 532 emptyarglist(&fn); 533 switch (redir->type) { 534 case NFROM: 535 case NTO: 536 case NFROMTO: 537 case NAPPEND: 538 case NCLOBBER: 539 expandarg(redir->nfile.fname, &fn, EXP_TILDE); 540 redir->nfile.expfname = fn.args[0]; 541 break; 542 case NFROMFD: 543 case NTOFD: 544 if (redir->ndup.vname) { 545 expandarg(redir->ndup.vname, &fn, EXP_TILDE); 546 fixredir(redir, fn.args[0], 1); 547 } 548 break; 549 case NXHERE: 550 exphere(redir, &fn); 551 break; 552 } 553 } 554 } 555 556 557 558 /* 559 * Evaluate a pipeline. All the processes in the pipeline are children 560 * of the process creating the pipeline. (This differs from some versions 561 * of the shell, which make the last process in a pipeline the parent 562 * of all the rest.) 563 */ 564 565 static void 566 evalpipe(union node *n) 567 { 568 struct job *jp; 569 struct nodelist *lp; 570 int pipelen; 571 int prevfd; 572 int pip[2]; 573 574 TRACE(("evalpipe(%p) called\n", (void *)n)); 575 pipelen = 0; 576 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 577 pipelen++; 578 INTOFF; 579 jp = makejob(n, pipelen); 580 prevfd = -1; 581 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 582 prehash(lp->n); 583 pip[1] = -1; 584 if (lp->next) { 585 if (pipe(pip) < 0) { 586 if (prevfd >= 0) 587 close(prevfd); 588 error("Pipe call failed: %s", strerror(errno)); 589 } 590 } 591 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 592 INTON; 593 if (prevfd > 0) { 594 dup2(prevfd, 0); 595 close(prevfd); 596 } 597 if (pip[1] >= 0) { 598 if (!(prevfd >= 0 && pip[0] == 0)) 599 close(pip[0]); 600 if (pip[1] != 1) { 601 dup2(pip[1], 1); 602 close(pip[1]); 603 } 604 } 605 evaltree(lp->n, EV_EXIT); 606 } 607 if (prevfd >= 0) 608 close(prevfd); 609 prevfd = pip[0]; 610 if (pip[1] != -1) 611 close(pip[1]); 612 } 613 INTON; 614 if (n->npipe.backgnd == 0) { 615 INTOFF; 616 exitstatus = waitforjob(jp, (int *)NULL); 617 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 618 INTON; 619 } else 620 exitstatus = 0; 621 } 622 623 624 625 static int 626 is_valid_fast_cmdsubst(union node *n) 627 { 628 629 return (n->type == NCMD); 630 } 631 632 /* 633 * Execute a command inside back quotes. If it's a builtin command, we 634 * want to save its output in a block obtained from malloc. Otherwise 635 * we fork off a subprocess and get the output of the command via a pipe. 636 * Should be called with interrupts off. 637 */ 638 639 void 640 evalbackcmd(union node *n, struct backcmd *result) 641 { 642 int pip[2]; 643 struct job *jp; 644 struct stackmark smark; 645 struct jmploc jmploc; 646 struct jmploc *savehandler; 647 struct localvar *savelocalvars; 648 unsigned char saveoptreset; 649 650 result->fd = -1; 651 result->buf = NULL; 652 result->nleft = 0; 653 result->jp = NULL; 654 if (n == NULL) { 655 exitstatus = 0; 656 return; 657 } 658 setstackmark(&smark); 659 exitstatus = oexitstatus; 660 if (is_valid_fast_cmdsubst(n)) { 661 savelocalvars = localvars; 662 localvars = NULL; 663 saveoptreset = shellparam.reset; 664 forcelocal++; 665 savehandler = handler; 666 if (setjmp(jmploc.loc)) { 667 if (exception == EXERROR) 668 /* nothing */; 669 else if (exception != 0) { 670 handler = savehandler; 671 forcelocal--; 672 poplocalvars(); 673 localvars = savelocalvars; 674 shellparam.reset = saveoptreset; 675 longjmp(handler->loc, 1); 676 } 677 } else { 678 handler = &jmploc; 679 evalcommand(n, EV_BACKCMD, result); 680 } 681 handler = savehandler; 682 forcelocal--; 683 poplocalvars(); 684 localvars = savelocalvars; 685 shellparam.reset = saveoptreset; 686 } else { 687 if (pipe(pip) < 0) 688 error("Pipe call failed: %s", strerror(errno)); 689 jp = makejob(n, 1); 690 if (forkshell(jp, n, FORK_NOJOB) == 0) { 691 FORCEINTON; 692 close(pip[0]); 693 if (pip[1] != 1) { 694 dup2(pip[1], 1); 695 close(pip[1]); 696 } 697 evaltree(n, EV_EXIT); 698 } 699 close(pip[1]); 700 result->fd = pip[0]; 701 result->jp = jp; 702 } 703 popstackmark(&smark); 704 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 705 result->fd, result->buf, result->nleft, result->jp)); 706 } 707 708 static int 709 mustexpandto(const char *argtext, const char *mask) 710 { 711 for (;;) { 712 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) { 713 argtext++; 714 continue; 715 } 716 if (*argtext == CTLESC) 717 argtext++; 718 else if (BASESYNTAX[(int)*argtext] == CCTL) 719 return (0); 720 if (*argtext != *mask) 721 return (0); 722 if (*argtext == '\0') 723 return (1); 724 argtext++; 725 mask++; 726 } 727 } 728 729 static int 730 isdeclarationcmd(struct narg *arg) 731 { 732 int have_command = 0; 733 734 if (arg == NULL) 735 return (0); 736 while (mustexpandto(arg->text, "command")) { 737 have_command = 1; 738 arg = &arg->next->narg; 739 if (arg == NULL) 740 return (0); 741 /* 742 * To also allow "command -p" and "command --" as part of 743 * a declaration command, add code here. 744 * We do not do this, as ksh does not do it either and it 745 * is not required by POSIX. 746 */ 747 } 748 return (mustexpandto(arg->text, "export") || 749 mustexpandto(arg->text, "readonly") || 750 (mustexpandto(arg->text, "local") && 751 (have_command || !isfunc("local")))); 752 } 753 754 static void 755 xtracecommand(struct arglist *varlist, int argc, char **argv) 756 { 757 char sep = 0; 758 const char *text, *p, *ps4; 759 int i; 760 761 ps4 = expandstr(ps4val()); 762 out2str(ps4 != NULL ? ps4 : ps4val()); 763 for (i = 0; i < varlist->count; i++) { 764 text = varlist->args[i]; 765 if (sep != 0) 766 out2c(' '); 767 p = strchr(text, '='); 768 if (p != NULL) { 769 p++; 770 outbin(text, p - text, out2); 771 out2qstr(p); 772 } else 773 out2qstr(text); 774 sep = ' '; 775 } 776 for (i = 0; i < argc; i++) { 777 text = argv[i]; 778 if (sep != 0) 779 out2c(' '); 780 out2qstr(text); 781 sep = ' '; 782 } 783 out2c('\n'); 784 flushout(&errout); 785 } 786 787 /* 788 * Check if a builtin can safely be executed in the same process, 789 * even though it should be in a subshell (command substitution). 790 * Note that jobid, jobs, times and trap can show information not 791 * available in a child process; this is deliberate. 792 * The arguments should already have been expanded. 793 */ 794 static int 795 safe_builtin(int idx, int argc, char **argv) 796 { 797 /* Generated from builtins.def. */ 798 if (safe_builtin_always(idx)) 799 return (1); 800 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 801 idx == UMASKCMD) 802 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 803 if (idx == SETCMD) 804 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 805 argv[1][0] == '+') && argv[1][1] == 'o' && 806 argv[1][2] == '\0')); 807 return (0); 808 } 809 810 /* 811 * Execute a simple command. 812 * Note: This may or may not return if (flags & EV_EXIT). 813 */ 814 815 static void 816 evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 817 { 818 union node *argp; 819 struct arglist arglist; 820 struct arglist varlist; 821 char **argv; 822 int argc; 823 char **envp; 824 int varflag; 825 int mode; 826 int pip[2]; 827 struct cmdentry cmdentry; 828 struct job *jp; 829 struct jmploc jmploc; 830 struct jmploc *savehandler; 831 char *savecmdname; 832 struct shparam saveparam; 833 struct localvar *savelocalvars; 834 struct parsefile *savetopfile; 835 volatile int e; 836 char *lastarg; 837 int signaled; 838 int do_clearcmdentry; 839 const char *path = pathval(); 840 int i; 841 842 /* First expand the arguments. */ 843 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 844 emptyarglist(&arglist); 845 emptyarglist(&varlist); 846 varflag = 1; 847 jp = NULL; 848 do_clearcmdentry = 0; 849 oexitstatus = exitstatus; 850 exitstatus = 0; 851 /* Add one slot at the beginning for tryexec(). */ 852 appendarglist(&arglist, nullstr); 853 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 854 if (varflag && isassignment(argp->narg.text)) { 855 expandarg(argp, varflag == 1 ? &varlist : &arglist, 856 EXP_VARTILDE); 857 continue; 858 } else if (varflag == 1) 859 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0; 860 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 861 } 862 appendarglist(&arglist, nullstr); 863 expredir(cmd->ncmd.redirect); 864 argc = arglist.count - 2; 865 argv = &arglist.args[1]; 866 867 argv[argc] = NULL; 868 lastarg = NULL; 869 if (iflag && funcnest == 0 && argc > 0) 870 lastarg = argv[argc - 1]; 871 872 /* Print the command if xflag is set. */ 873 if (xflag) 874 xtracecommand(&varlist, argc, argv); 875 876 /* Now locate the command. */ 877 if (argc == 0) { 878 /* Variable assignment(s) without command */ 879 cmdentry.cmdtype = CMDBUILTIN; 880 cmdentry.u.index = BLTINCMD; 881 cmdentry.special = 0; 882 } else { 883 static const char PATH[] = "PATH="; 884 int cmd_flags = 0, bltinonly = 0; 885 886 /* 887 * Modify the command lookup path, if a PATH= assignment 888 * is present 889 */ 890 for (i = 0; i < varlist.count; i++) 891 if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) { 892 path = varlist.args[i] + sizeof(PATH) - 1; 893 /* 894 * On `PATH=... command`, we need to make 895 * sure that the command isn't using the 896 * non-updated hash table of the outer PATH 897 * setting and we need to make sure that 898 * the hash table isn't filled with items 899 * from the temporary setting. 900 * 901 * It would be better to forbid using and 902 * updating the table while this command 903 * runs, by the command finding mechanism 904 * is heavily integrated with hash handling, 905 * so we just delete the hash before and after 906 * the command runs. Partly deleting like 907 * changepatch() does doesn't seem worth the 908 * bookinging effort, since most such runs add 909 * directories in front of the new PATH. 910 */ 911 clearcmdentry(); 912 do_clearcmdentry = 1; 913 } 914 915 for (;;) { 916 if (bltinonly) { 917 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 918 if (cmdentry.u.index < 0) { 919 cmdentry.u.index = BLTINCMD; 920 argv--; 921 argc++; 922 break; 923 } 924 } else 925 find_command(argv[0], &cmdentry, cmd_flags, path); 926 /* implement the bltin and command builtins here */ 927 if (cmdentry.cmdtype != CMDBUILTIN) 928 break; 929 if (cmdentry.u.index == BLTINCMD) { 930 if (argc == 1) 931 break; 932 argv++; 933 argc--; 934 bltinonly = 1; 935 } else if (cmdentry.u.index == COMMANDCMD) { 936 if (argc == 1) 937 break; 938 if (!strcmp(argv[1], "-p")) { 939 if (argc == 2) 940 break; 941 if (argv[2][0] == '-') { 942 if (strcmp(argv[2], "--")) 943 break; 944 if (argc == 3) 945 break; 946 argv += 3; 947 argc -= 3; 948 } else { 949 argv += 2; 950 argc -= 2; 951 } 952 path = _PATH_STDPATH; 953 clearcmdentry(); 954 do_clearcmdentry = 1; 955 } else if (!strcmp(argv[1], "--")) { 956 if (argc == 2) 957 break; 958 argv += 2; 959 argc -= 2; 960 } else if (argv[1][0] == '-') 961 break; 962 else { 963 argv++; 964 argc--; 965 } 966 cmd_flags |= DO_NOFUNC; 967 bltinonly = 0; 968 } else 969 break; 970 } 971 /* 972 * Special builtins lose their special properties when 973 * called via 'command'. 974 */ 975 if (cmd_flags & DO_NOFUNC) 976 cmdentry.special = 0; 977 } 978 979 /* Fork off a child process if necessary. */ 980 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 981 && ((flags & EV_EXIT) == 0 || have_traps())) 982 || ((flags & EV_BACKCMD) != 0 983 && (cmdentry.cmdtype != CMDBUILTIN || 984 !safe_builtin(cmdentry.u.index, argc, argv)))) { 985 jp = makejob(cmd, 1); 986 mode = FORK_FG; 987 if (flags & EV_BACKCMD) { 988 mode = FORK_NOJOB; 989 if (pipe(pip) < 0) 990 error("Pipe call failed: %s", strerror(errno)); 991 } 992 if (cmdentry.cmdtype == CMDNORMAL && 993 cmd->ncmd.redirect == NULL && 994 varlist.count == 0 && 995 (mode == FORK_FG || mode == FORK_NOJOB) && 996 !disvforkset() && !iflag && !mflag) { 997 vforkexecshell(jp, argv, environment(), path, 998 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL); 999 goto parent; 1000 } 1001 if (forkshell(jp, cmd, mode) != 0) 1002 goto parent; /* at end of routine */ 1003 if (flags & EV_BACKCMD) { 1004 FORCEINTON; 1005 close(pip[0]); 1006 if (pip[1] != 1) { 1007 dup2(pip[1], 1); 1008 close(pip[1]); 1009 } 1010 flags &= ~EV_BACKCMD; 1011 } 1012 flags |= EV_EXIT; 1013 } 1014 1015 /* This is the child process if a fork occurred. */ 1016 /* Execute the command. */ 1017 if (cmdentry.cmdtype == CMDFUNCTION) { 1018 #ifdef DEBUG 1019 trputs("Shell function: "); trargs(argv); 1020 #endif 1021 saveparam = shellparam; 1022 shellparam.malloc = 0; 1023 shellparam.reset = 1; 1024 shellparam.nparam = argc - 1; 1025 shellparam.p = argv + 1; 1026 shellparam.optp = NULL; 1027 shellparam.optnext = NULL; 1028 INTOFF; 1029 savelocalvars = localvars; 1030 localvars = NULL; 1031 reffunc(cmdentry.u.func); 1032 savehandler = handler; 1033 if (setjmp(jmploc.loc)) { 1034 popredir(); 1035 unreffunc(cmdentry.u.func); 1036 poplocalvars(); 1037 localvars = savelocalvars; 1038 freeparam(&shellparam); 1039 shellparam = saveparam; 1040 funcnest--; 1041 handler = savehandler; 1042 longjmp(handler->loc, 1); 1043 } 1044 handler = &jmploc; 1045 funcnest++; 1046 redirect(cmd->ncmd.redirect, REDIR_PUSH); 1047 INTON; 1048 for (i = 0; i < varlist.count; i++) 1049 mklocal(varlist.args[i]); 1050 exitstatus = oexitstatus; 1051 evaltree(getfuncnode(cmdentry.u.func), 1052 flags & (EV_TESTED | EV_EXIT)); 1053 INTOFF; 1054 unreffunc(cmdentry.u.func); 1055 poplocalvars(); 1056 localvars = savelocalvars; 1057 freeparam(&shellparam); 1058 shellparam = saveparam; 1059 handler = savehandler; 1060 funcnest--; 1061 popredir(); 1062 INTON; 1063 if (evalskip == SKIPRETURN) { 1064 evalskip = 0; 1065 skipcount = 0; 1066 } 1067 if (jp) 1068 exitshell(exitstatus); 1069 } else if (cmdentry.cmdtype == CMDBUILTIN) { 1070 #ifdef DEBUG 1071 trputs("builtin command: "); trargs(argv); 1072 #endif 1073 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 1074 if (flags == EV_BACKCMD) { 1075 memout.nextc = memout.buf; 1076 mode |= REDIR_BACKQ; 1077 } 1078 savecmdname = commandname; 1079 savetopfile = getcurrentfile(); 1080 cmdenviron = &varlist; 1081 e = -1; 1082 savehandler = handler; 1083 if (setjmp(jmploc.loc)) { 1084 e = exception; 1085 if (e == EXINT) 1086 exitstatus = SIGINT+128; 1087 goto cmddone; 1088 } 1089 handler = &jmploc; 1090 redirect(cmd->ncmd.redirect, mode); 1091 outclearerror(out1); 1092 /* 1093 * If there is no command word, redirection errors should 1094 * not be fatal but assignment errors should. 1095 */ 1096 if (argc == 0) 1097 cmdentry.special = 1; 1098 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1099 if (argc > 0) 1100 bltinsetlocale(); 1101 commandname = argv[0]; 1102 argptr = argv + 1; 1103 nextopt_optptr = NULL; /* initialize nextopt */ 1104 builtin_flags = flags; 1105 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1106 flushall(); 1107 if (outiserror(out1)) { 1108 warning("write error on stdout"); 1109 if (exitstatus == 0 || exitstatus == 1) 1110 exitstatus = 2; 1111 } 1112 cmddone: 1113 if (argc > 0) 1114 bltinunsetlocale(); 1115 cmdenviron = NULL; 1116 out1 = &output; 1117 out2 = &errout; 1118 freestdout(); 1119 handler = savehandler; 1120 commandname = savecmdname; 1121 if (jp) 1122 exitshell(exitstatus); 1123 if (flags == EV_BACKCMD) { 1124 backcmd->buf = memout.buf; 1125 backcmd->nleft = memout.buf != NULL ? 1126 memout.nextc - memout.buf : 0; 1127 memout.buf = NULL; 1128 memout.nextc = NULL; 1129 memout.bufend = NULL; 1130 memout.bufsize = 64; 1131 } 1132 if (cmdentry.u.index != EXECCMD) 1133 popredir(); 1134 if (e != -1) { 1135 if (e != EXERROR || cmdentry.special) 1136 exraise(e); 1137 popfilesupto(savetopfile); 1138 if (flags != EV_BACKCMD) 1139 FORCEINTON; 1140 } 1141 } else { 1142 #ifdef DEBUG 1143 trputs("normal command: "); trargs(argv); 1144 #endif 1145 redirect(cmd->ncmd.redirect, 0); 1146 for (i = 0; i < varlist.count; i++) 1147 setvareq(varlist.args[i], VEXPORT|VSTACK); 1148 envp = environment(); 1149 shellexec(argv, envp, path, cmdentry.u.index); 1150 /*NOTREACHED*/ 1151 } 1152 goto out; 1153 1154 parent: /* parent process gets here (if we forked) */ 1155 if (mode == FORK_FG) { /* argument to fork */ 1156 INTOFF; 1157 exitstatus = waitforjob(jp, &signaled); 1158 INTON; 1159 if (iflag && loopnest > 0 && signaled) { 1160 evalskip = SKIPBREAK; 1161 skipcount = loopnest; 1162 } 1163 } else if (mode == FORK_NOJOB) { 1164 backcmd->fd = pip[0]; 1165 close(pip[1]); 1166 backcmd->jp = jp; 1167 } 1168 1169 out: 1170 if (lastarg) 1171 setvar("_", lastarg, 0); 1172 if (do_clearcmdentry) 1173 clearcmdentry(); 1174 } 1175 1176 1177 1178 /* 1179 * Search for a command. This is called before we fork so that the 1180 * location of the command will be available in the parent as well as 1181 * the child. The check for "goodname" is an overly conservative 1182 * check that the name will not be subject to expansion. 1183 */ 1184 1185 static void 1186 prehash(union node *n) 1187 { 1188 struct cmdentry entry; 1189 1190 if (n && n->type == NCMD && n->ncmd.args) 1191 if (goodname(n->ncmd.args->narg.text)) 1192 find_command(n->ncmd.args->narg.text, &entry, 0, 1193 pathval()); 1194 } 1195 1196 1197 1198 /* 1199 * Builtin commands. Builtin commands whose functions are closely 1200 * tied to evaluation are implemented here. 1201 */ 1202 1203 /* 1204 * No command given, a bltin command with no arguments, or a bltin command 1205 * with an invalid name. 1206 */ 1207 1208 int 1209 bltincmd(int argc, char **argv) 1210 { 1211 if (argc > 1) { 1212 out2fmt_flush("%s: not found\n", argv[1]); 1213 return 127; 1214 } 1215 /* 1216 * Preserve exitstatus of a previous possible command substitution 1217 * as POSIX mandates 1218 */ 1219 return exitstatus; 1220 } 1221 1222 1223 /* 1224 * Handle break and continue commands. Break, continue, and return are 1225 * all handled by setting the evalskip flag. The evaluation routines 1226 * above all check this flag, and if it is set they start skipping 1227 * commands rather than executing them. The variable skipcount is 1228 * the number of loops to break/continue, or the number of function 1229 * levels to return. (The latter is always 1.) It should probably 1230 * be an error to break out of more loops than exist, but it isn't 1231 * in the standard shell so we don't make it one here. 1232 */ 1233 1234 int 1235 breakcmd(int argc, char **argv) 1236 { 1237 long n; 1238 char *end; 1239 1240 if (argc > 1) { 1241 /* Allow arbitrarily large numbers. */ 1242 n = strtol(argv[1], &end, 10); 1243 if (!is_digit(argv[1][0]) || *end != '\0') 1244 error("Illegal number: %s", argv[1]); 1245 } else 1246 n = 1; 1247 if (n > loopnest) 1248 n = loopnest; 1249 if (n > 0) { 1250 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1251 skipcount = n; 1252 } 1253 return 0; 1254 } 1255 1256 /* 1257 * The `command' command. 1258 */ 1259 int 1260 commandcmd(int argc __unused, char **argv __unused) 1261 { 1262 const char *path; 1263 int ch; 1264 int cmd = -1; 1265 1266 path = bltinlookup("PATH", 1); 1267 1268 while ((ch = nextopt("pvV")) != '\0') { 1269 switch (ch) { 1270 case 'p': 1271 path = _PATH_STDPATH; 1272 break; 1273 case 'v': 1274 cmd = TYPECMD_SMALLV; 1275 break; 1276 case 'V': 1277 cmd = TYPECMD_BIGV; 1278 break; 1279 } 1280 } 1281 1282 if (cmd != -1) { 1283 if (*argptr == NULL || argptr[1] != NULL) 1284 error("wrong number of arguments"); 1285 return typecmd_impl(2, argptr - 1, cmd, path); 1286 } 1287 if (*argptr != NULL) 1288 error("commandcmd bad call"); 1289 1290 /* 1291 * Do nothing successfully if no command was specified; 1292 * ksh also does this. 1293 */ 1294 return 0; 1295 } 1296 1297 1298 /* 1299 * The return command. 1300 */ 1301 1302 int 1303 returncmd(int argc, char **argv) 1304 { 1305 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1306 1307 evalskip = SKIPRETURN; 1308 skipcount = 1; 1309 return ret; 1310 } 1311 1312 1313 int 1314 falsecmd(int argc __unused, char **argv __unused) 1315 { 1316 return 1; 1317 } 1318 1319 1320 int 1321 truecmd(int argc __unused, char **argv __unused) 1322 { 1323 return 0; 1324 } 1325 1326 1327 int 1328 execcmd(int argc, char **argv) 1329 { 1330 int i; 1331 1332 /* 1333 * Because we have historically not supported any options, 1334 * only treat "--" specially. 1335 */ 1336 if (argc > 1 && strcmp(argv[1], "--") == 0) 1337 argc--, argv++; 1338 if (argc > 1) { 1339 iflag = 0; /* exit on error */ 1340 mflag = 0; 1341 optschanged(); 1342 for (i = 0; i < cmdenviron->count; i++) 1343 setvareq(cmdenviron->args[i], VEXPORT|VSTACK); 1344 shellexec(argv + 1, environment(), pathval(), 0); 1345 1346 } 1347 return 0; 1348 } 1349 1350 1351 int 1352 timescmd(int argc __unused, char **argv __unused) 1353 { 1354 struct rusage ru; 1355 long shumins, shsmins, chumins, chsmins; 1356 double shusecs, shssecs, chusecs, chssecs; 1357 1358 if (getrusage(RUSAGE_SELF, &ru) < 0) 1359 return 1; 1360 shumins = ru.ru_utime.tv_sec / 60; 1361 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1362 shsmins = ru.ru_stime.tv_sec / 60; 1363 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1364 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1365 return 1; 1366 chumins = ru.ru_utime.tv_sec / 60; 1367 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1368 chsmins = ru.ru_stime.tv_sec / 60; 1369 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1370 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1371 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1372 return 0; 1373 } 1374