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 __FBSDID("$FreeBSD$"); 40 41 #include <paths.h> 42 #include <signal.h> 43 #include <stdlib.h> 44 #include <unistd.h> 45 #include <sys/resource.h> 46 #include <errno.h> 47 48 /* 49 * Evaluate a command. 50 */ 51 52 #include "shell.h" 53 #include "nodes.h" 54 #include "syntax.h" 55 #include "expand.h" 56 #include "parser.h" 57 #include "jobs.h" 58 #include "eval.h" 59 #include "builtins.h" 60 #include "options.h" 61 #include "exec.h" 62 #include "redir.h" 63 #include "input.h" 64 #include "output.h" 65 #include "trap.h" 66 #include "var.h" 67 #include "memalloc.h" 68 #include "error.h" 69 #include "show.h" 70 #include "mystring.h" 71 #ifndef NO_HISTORY 72 #include "myhistedit.h" 73 #endif 74 75 76 int evalskip; /* set if we are skipping commands */ 77 int skipcount; /* number of levels to skip */ 78 static int loopnest; /* current loop nesting level */ 79 int funcnest; /* depth of function calls */ 80 static int builtin_flags; /* evalcommand flags for builtins */ 81 82 83 char *commandname; 84 struct arglist *cmdenviron; 85 int exitstatus; /* exit status of last command */ 86 int oexitstatus; /* saved exit status */ 87 88 89 static void evalloop(union node *, int); 90 static void evalfor(union node *, int); 91 static union node *evalcase(union node *); 92 static void evalsubshell(union node *, int); 93 static void evalredir(union node *, int); 94 static void exphere(union node *, struct arglist *); 95 static void expredir(union node *); 96 static void evalpipe(union node *); 97 static int is_valid_fast_cmdsubst(union node *n); 98 static void evalcommand(union node *, int, struct backcmd *); 99 static void prehash(union node *); 100 101 102 /* 103 * Called to reset things after an exception. 104 */ 105 106 void 107 reseteval(void) 108 { 109 evalskip = 0; 110 loopnest = 0; 111 } 112 113 114 /* 115 * The eval command. 116 */ 117 118 int 119 evalcmd(int argc, char **argv) 120 { 121 char *p; 122 char *concat; 123 char **ap; 124 125 if (argc > 1) { 126 p = argv[1]; 127 if (argc > 2) { 128 STARTSTACKSTR(concat); 129 ap = argv + 2; 130 for (;;) { 131 STPUTS(p, concat); 132 if ((p = *ap++) == NULL) 133 break; 134 STPUTC(' ', concat); 135 } 136 STPUTC('\0', concat); 137 p = grabstackstr(concat); 138 } 139 evalstring(p, builtin_flags); 140 } else 141 exitstatus = 0; 142 return exitstatus; 143 } 144 145 146 /* 147 * Execute a command or commands contained in a string. 148 */ 149 150 void 151 evalstring(const char *s, int flags) 152 { 153 union node *n; 154 struct stackmark smark; 155 int flags_exit; 156 int any; 157 158 flags_exit = flags & EV_EXIT; 159 flags &= ~EV_EXIT; 160 any = 0; 161 setstackmark(&smark); 162 setinputstring(s, 1); 163 while ((n = parsecmd(0)) != NEOF) { 164 if (n != NULL && !nflag) { 165 if (flags_exit && preadateof()) 166 evaltree(n, flags | EV_EXIT); 167 else 168 evaltree(n, flags); 169 any = 1; 170 if (evalskip) 171 break; 172 } 173 popstackmark(&smark); 174 setstackmark(&smark); 175 } 176 popfile(); 177 popstackmark(&smark); 178 if (!any) 179 exitstatus = 0; 180 if (flags_exit) 181 exraise(EXEXIT); 182 } 183 184 185 /* 186 * Evaluate a parse tree. The value is left in the global variable 187 * exitstatus. 188 */ 189 190 void 191 evaltree(union node *n, int flags) 192 { 193 int do_etest; 194 union node *next; 195 struct stackmark smark; 196 197 setstackmark(&smark); 198 do_etest = 0; 199 if (n == NULL) { 200 TRACE(("evaltree(NULL) called\n")); 201 exitstatus = 0; 202 goto out; 203 } 204 do { 205 next = NULL; 206 #ifndef NO_HISTORY 207 displayhist = 1; /* show history substitutions done with fc */ 208 #endif 209 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 210 switch (n->type) { 211 case NSEMI: 212 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 213 if (evalskip) 214 goto out; 215 next = n->nbinary.ch2; 216 break; 217 case NAND: 218 evaltree(n->nbinary.ch1, EV_TESTED); 219 if (evalskip || exitstatus != 0) { 220 goto out; 221 } 222 next = n->nbinary.ch2; 223 break; 224 case NOR: 225 evaltree(n->nbinary.ch1, EV_TESTED); 226 if (evalskip || exitstatus == 0) 227 goto out; 228 next = n->nbinary.ch2; 229 break; 230 case NREDIR: 231 evalredir(n, flags); 232 break; 233 case NSUBSHELL: 234 evalsubshell(n, flags); 235 do_etest = !(flags & EV_TESTED); 236 break; 237 case NBACKGND: 238 evalsubshell(n, flags); 239 break; 240 case NIF: { 241 evaltree(n->nif.test, EV_TESTED); 242 if (evalskip) 243 goto out; 244 if (exitstatus == 0) 245 next = n->nif.ifpart; 246 else if (n->nif.elsepart) 247 next = n->nif.elsepart; 248 else 249 exitstatus = 0; 250 break; 251 } 252 case NWHILE: 253 case NUNTIL: 254 evalloop(n, flags & ~EV_EXIT); 255 break; 256 case NFOR: 257 evalfor(n, flags & ~EV_EXIT); 258 break; 259 case NCASE: 260 next = evalcase(n); 261 break; 262 case NCLIST: 263 next = n->nclist.body; 264 break; 265 case NCLISTFALLTHRU: 266 if (n->nclist.body) { 267 evaltree(n->nclist.body, flags & ~EV_EXIT); 268 if (evalskip) 269 goto out; 270 } 271 next = n->nclist.next; 272 break; 273 case NDEFUN: 274 defun(n->narg.text, n->narg.next); 275 exitstatus = 0; 276 break; 277 case NNOT: 278 evaltree(n->nnot.com, EV_TESTED); 279 if (evalskip) 280 goto out; 281 exitstatus = !exitstatus; 282 break; 283 284 case NPIPE: 285 evalpipe(n); 286 do_etest = !(flags & EV_TESTED); 287 break; 288 case NCMD: 289 evalcommand(n, flags, (struct backcmd *)NULL); 290 do_etest = !(flags & EV_TESTED); 291 break; 292 default: 293 out1fmt("Node type = %d\n", n->type); 294 flushout(&output); 295 break; 296 } 297 n = next; 298 popstackmark(&smark); 299 setstackmark(&smark); 300 } while (n != NULL); 301 out: 302 popstackmark(&smark); 303 if (pendingsig) 304 dotrap(); 305 if (eflag && exitstatus != 0 && do_etest) 306 exitshell(exitstatus); 307 if (flags & EV_EXIT) 308 exraise(EXEXIT); 309 } 310 311 312 static void 313 evalloop(union node *n, int flags) 314 { 315 int status; 316 317 loopnest++; 318 status = 0; 319 for (;;) { 320 if (!evalskip) 321 evaltree(n->nbinary.ch1, EV_TESTED); 322 if (evalskip) { 323 if (evalskip == SKIPCONT && --skipcount <= 0) { 324 evalskip = 0; 325 continue; 326 } 327 if (evalskip == SKIPBREAK && --skipcount <= 0) 328 evalskip = 0; 329 if (evalskip == SKIPRETURN) 330 status = exitstatus; 331 break; 332 } 333 if (n->type == NWHILE) { 334 if (exitstatus != 0) 335 break; 336 } else { 337 if (exitstatus == 0) 338 break; 339 } 340 evaltree(n->nbinary.ch2, flags); 341 status = exitstatus; 342 } 343 loopnest--; 344 exitstatus = status; 345 } 346 347 348 349 static void 350 evalfor(union node *n, int flags) 351 { 352 struct arglist arglist; 353 union node *argp; 354 int i; 355 int status; 356 357 emptyarglist(&arglist); 358 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 359 oexitstatus = exitstatus; 360 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 361 } 362 363 loopnest++; 364 status = 0; 365 for (i = 0; i < arglist.count; i++) { 366 setvar(n->nfor.var, arglist.args[i], 0); 367 evaltree(n->nfor.body, flags); 368 status = exitstatus; 369 if (evalskip) { 370 if (evalskip == SKIPCONT && --skipcount <= 0) { 371 evalskip = 0; 372 continue; 373 } 374 if (evalskip == SKIPBREAK && --skipcount <= 0) 375 evalskip = 0; 376 break; 377 } 378 } 379 loopnest--; 380 exitstatus = status; 381 } 382 383 384 /* 385 * Evaluate a case statement, returning the selected tree. 386 * 387 * The exit status needs care to get right. 388 */ 389 390 static union node * 391 evalcase(union node *n) 392 { 393 union node *cp; 394 union node *patp; 395 struct arglist arglist; 396 397 emptyarglist(&arglist); 398 oexitstatus = exitstatus; 399 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 400 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) { 401 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 402 if (casematch(patp, arglist.args[0])) { 403 while (cp->nclist.next && 404 cp->type == NCLISTFALLTHRU && 405 cp->nclist.body == NULL) 406 cp = cp->nclist.next; 407 if (cp->nclist.next && 408 cp->type == NCLISTFALLTHRU) 409 return (cp); 410 if (cp->nclist.body == NULL) 411 exitstatus = 0; 412 return (cp->nclist.body); 413 } 414 } 415 } 416 exitstatus = 0; 417 return (NULL); 418 } 419 420 421 422 /* 423 * Kick off a subshell to evaluate a tree. 424 */ 425 426 static void 427 evalsubshell(union node *n, int flags) 428 { 429 struct job *jp; 430 int backgnd = (n->type == NBACKGND); 431 432 oexitstatus = exitstatus; 433 expredir(n->nredir.redirect); 434 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 435 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 436 if (backgnd) 437 flags &=~ EV_TESTED; 438 redirect(n->nredir.redirect, 0); 439 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 440 } else if (! backgnd) { 441 INTOFF; 442 exitstatus = waitforjob(jp, (int *)NULL); 443 INTON; 444 } else 445 exitstatus = 0; 446 } 447 448 449 /* 450 * Evaluate a redirected compound command. 451 */ 452 453 static void 454 evalredir(union node *n, int flags) 455 { 456 struct jmploc jmploc; 457 struct jmploc *savehandler; 458 volatile int in_redirect = 1; 459 460 oexitstatus = exitstatus; 461 expredir(n->nredir.redirect); 462 savehandler = handler; 463 if (setjmp(jmploc.loc)) { 464 int e; 465 466 handler = savehandler; 467 e = exception; 468 popredir(); 469 if (e == EXERROR || e == EXEXEC) { 470 if (in_redirect) { 471 exitstatus = 2; 472 FORCEINTON; 473 return; 474 } 475 } 476 longjmp(handler->loc, 1); 477 } else { 478 INTOFF; 479 handler = &jmploc; 480 redirect(n->nredir.redirect, REDIR_PUSH); 481 in_redirect = 0; 482 INTON; 483 evaltree(n->nredir.n, flags); 484 } 485 INTOFF; 486 handler = savehandler; 487 popredir(); 488 INTON; 489 } 490 491 492 static void 493 exphere(union node *redir, struct arglist *fn) 494 { 495 struct jmploc jmploc; 496 struct jmploc *savehandler; 497 struct localvar *savelocalvars; 498 int need_longjmp = 0; 499 unsigned char saveoptreset; 500 501 redir->nhere.expdoc = ""; 502 savelocalvars = localvars; 503 localvars = NULL; 504 saveoptreset = shellparam.reset; 505 forcelocal++; 506 savehandler = handler; 507 if (setjmp(jmploc.loc)) 508 need_longjmp = exception != EXERROR && exception != EXEXEC; 509 else { 510 handler = &jmploc; 511 expandarg(redir->nhere.doc, fn, 0); 512 redir->nhere.expdoc = fn->args[0]; 513 INTOFF; 514 } 515 handler = savehandler; 516 forcelocal--; 517 poplocalvars(); 518 localvars = savelocalvars; 519 shellparam.reset = saveoptreset; 520 if (need_longjmp) 521 longjmp(handler->loc, 1); 522 INTON; 523 } 524 525 526 /* 527 * Compute the names of the files in a redirection list. 528 */ 529 530 static void 531 expredir(union node *n) 532 { 533 union node *redir; 534 535 for (redir = n ; redir ; redir = redir->nfile.next) { 536 struct arglist fn; 537 emptyarglist(&fn); 538 switch (redir->type) { 539 case NFROM: 540 case NTO: 541 case NFROMTO: 542 case NAPPEND: 543 case NCLOBBER: 544 expandarg(redir->nfile.fname, &fn, EXP_TILDE); 545 redir->nfile.expfname = fn.args[0]; 546 break; 547 case NFROMFD: 548 case NTOFD: 549 if (redir->ndup.vname) { 550 expandarg(redir->ndup.vname, &fn, EXP_TILDE); 551 fixredir(redir, fn.args[0], 1); 552 } 553 break; 554 case NXHERE: 555 exphere(redir, &fn); 556 break; 557 } 558 } 559 } 560 561 562 563 /* 564 * Evaluate a pipeline. All the processes in the pipeline are children 565 * of the process creating the pipeline. (This differs from some versions 566 * of the shell, which make the last process in a pipeline the parent 567 * of all the rest.) 568 */ 569 570 static void 571 evalpipe(union node *n) 572 { 573 struct job *jp; 574 struct nodelist *lp; 575 int pipelen; 576 int prevfd; 577 int pip[2]; 578 579 TRACE(("evalpipe(%p) called\n", (void *)n)); 580 pipelen = 0; 581 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 582 pipelen++; 583 INTOFF; 584 jp = makejob(n, pipelen); 585 prevfd = -1; 586 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 587 prehash(lp->n); 588 pip[1] = -1; 589 if (lp->next) { 590 if (pipe(pip) < 0) { 591 if (prevfd >= 0) 592 close(prevfd); 593 error("Pipe call failed: %s", strerror(errno)); 594 } 595 } 596 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 597 INTON; 598 if (prevfd > 0) { 599 dup2(prevfd, 0); 600 close(prevfd); 601 } 602 if (pip[1] >= 0) { 603 if (!(prevfd >= 0 && pip[0] == 0)) 604 close(pip[0]); 605 if (pip[1] != 1) { 606 dup2(pip[1], 1); 607 close(pip[1]); 608 } 609 } 610 evaltree(lp->n, EV_EXIT); 611 } 612 if (prevfd >= 0) 613 close(prevfd); 614 prevfd = pip[0]; 615 if (pip[1] != -1) 616 close(pip[1]); 617 } 618 INTON; 619 if (n->npipe.backgnd == 0) { 620 INTOFF; 621 exitstatus = waitforjob(jp, (int *)NULL); 622 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 623 INTON; 624 } else 625 exitstatus = 0; 626 } 627 628 629 630 static int 631 is_valid_fast_cmdsubst(union node *n) 632 { 633 634 return (n->type == NCMD); 635 } 636 637 /* 638 * Execute a command inside back quotes. If it's a builtin command, we 639 * want to save its output in a block obtained from malloc. Otherwise 640 * we fork off a subprocess and get the output of the command via a pipe. 641 * Should be called with interrupts off. 642 */ 643 644 void 645 evalbackcmd(union node *n, struct backcmd *result) 646 { 647 int pip[2]; 648 struct job *jp; 649 struct stackmark smark; 650 struct jmploc jmploc; 651 struct jmploc *savehandler; 652 struct localvar *savelocalvars; 653 unsigned char saveoptreset; 654 655 result->fd = -1; 656 result->buf = NULL; 657 result->nleft = 0; 658 result->jp = NULL; 659 if (n == NULL) { 660 exitstatus = 0; 661 return; 662 } 663 setstackmark(&smark); 664 exitstatus = oexitstatus; 665 if (is_valid_fast_cmdsubst(n)) { 666 savelocalvars = localvars; 667 localvars = NULL; 668 saveoptreset = shellparam.reset; 669 forcelocal++; 670 savehandler = handler; 671 if (setjmp(jmploc.loc)) { 672 if (exception == EXERROR || exception == EXEXEC) 673 exitstatus = 2; 674 else if (exception != 0) { 675 handler = savehandler; 676 forcelocal--; 677 poplocalvars(); 678 localvars = savelocalvars; 679 shellparam.reset = saveoptreset; 680 longjmp(handler->loc, 1); 681 } 682 } else { 683 handler = &jmploc; 684 evalcommand(n, EV_BACKCMD, result); 685 } 686 handler = savehandler; 687 forcelocal--; 688 poplocalvars(); 689 localvars = savelocalvars; 690 shellparam.reset = saveoptreset; 691 } else { 692 if (pipe(pip) < 0) 693 error("Pipe call failed: %s", strerror(errno)); 694 jp = makejob(n, 1); 695 if (forkshell(jp, n, FORK_NOJOB) == 0) { 696 FORCEINTON; 697 close(pip[0]); 698 if (pip[1] != 1) { 699 dup2(pip[1], 1); 700 close(pip[1]); 701 } 702 evaltree(n, EV_EXIT); 703 } 704 close(pip[1]); 705 result->fd = pip[0]; 706 result->jp = jp; 707 } 708 popstackmark(&smark); 709 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 710 result->fd, result->buf, result->nleft, result->jp)); 711 } 712 713 static int 714 mustexpandto(const char *argtext, const char *mask) 715 { 716 for (;;) { 717 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) { 718 argtext++; 719 continue; 720 } 721 if (*argtext == CTLESC) 722 argtext++; 723 else if (BASESYNTAX[(int)*argtext] == CCTL) 724 return (0); 725 if (*argtext != *mask) 726 return (0); 727 if (*argtext == '\0') 728 return (1); 729 argtext++; 730 mask++; 731 } 732 } 733 734 static int 735 isdeclarationcmd(struct narg *arg) 736 { 737 int have_command = 0; 738 739 if (arg == NULL) 740 return (0); 741 while (mustexpandto(arg->text, "command")) { 742 have_command = 1; 743 arg = &arg->next->narg; 744 if (arg == NULL) 745 return (0); 746 /* 747 * To also allow "command -p" and "command --" as part of 748 * a declaration command, add code here. 749 * We do not do this, as ksh does not do it either and it 750 * is not required by POSIX. 751 */ 752 } 753 return (mustexpandto(arg->text, "export") || 754 mustexpandto(arg->text, "readonly") || 755 (mustexpandto(arg->text, "local") && 756 (have_command || !isfunc("local")))); 757 } 758 759 static void 760 xtracecommand(struct arglist *varlist, int argc, char **argv) 761 { 762 char sep = 0; 763 const char *text, *p, *ps4; 764 int i; 765 766 ps4 = expandstr(ps4val()); 767 out2str(ps4 != NULL ? ps4 : ps4val()); 768 for (i = 0; i < varlist->count; i++) { 769 text = varlist->args[i]; 770 if (sep != 0) 771 out2c(' '); 772 p = strchr(text, '='); 773 if (p != NULL) { 774 p++; 775 outbin(text, p - text, out2); 776 out2qstr(p); 777 } else 778 out2qstr(text); 779 sep = ' '; 780 } 781 for (i = 0; i < argc; i++) { 782 text = argv[i]; 783 if (sep != 0) 784 out2c(' '); 785 out2qstr(text); 786 sep = ' '; 787 } 788 out2c('\n'); 789 flushout(&errout); 790 } 791 792 /* 793 * Check if a builtin can safely be executed in the same process, 794 * even though it should be in a subshell (command substitution). 795 * Note that jobid, jobs, times and trap can show information not 796 * available in a child process; this is deliberate. 797 * The arguments should already have been expanded. 798 */ 799 static int 800 safe_builtin(int idx, int argc, char **argv) 801 { 802 /* Generated from builtins.def. */ 803 if (safe_builtin_always(idx)) 804 return (1); 805 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 806 idx == UMASKCMD) 807 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 808 if (idx == SETCMD) 809 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 810 argv[1][0] == '+') && argv[1][1] == 'o' && 811 argv[1][2] == '\0')); 812 return (0); 813 } 814 815 /* 816 * Execute a simple command. 817 * Note: This may or may not return if (flags & EV_EXIT). 818 */ 819 820 static void 821 evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 822 { 823 union node *argp; 824 struct arglist arglist; 825 struct arglist varlist; 826 char **argv; 827 int argc; 828 char **envp; 829 int varflag; 830 int mode; 831 int pip[2]; 832 struct cmdentry cmdentry; 833 struct job *jp; 834 struct jmploc jmploc; 835 struct jmploc *savehandler; 836 char *savecmdname; 837 struct shparam saveparam; 838 struct localvar *savelocalvars; 839 struct parsefile *savetopfile; 840 volatile int e; 841 char *lastarg; 842 int signaled; 843 int do_clearcmdentry; 844 const char *path = pathval(); 845 int i; 846 847 /* First expand the arguments. */ 848 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 849 emptyarglist(&arglist); 850 emptyarglist(&varlist); 851 varflag = 1; 852 jp = NULL; 853 do_clearcmdentry = 0; 854 oexitstatus = exitstatus; 855 exitstatus = 0; 856 /* Add one slot at the beginning for tryexec(). */ 857 appendarglist(&arglist, nullstr); 858 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 859 if (varflag && isassignment(argp->narg.text)) { 860 expandarg(argp, varflag == 1 ? &varlist : &arglist, 861 EXP_VARTILDE); 862 continue; 863 } else if (varflag == 1) 864 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0; 865 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 866 } 867 appendarglist(&arglist, nullstr); 868 expredir(cmd->ncmd.redirect); 869 argc = arglist.count - 2; 870 argv = &arglist.args[1]; 871 872 argv[argc] = NULL; 873 lastarg = NULL; 874 if (iflag && funcnest == 0 && argc > 0) 875 lastarg = argv[argc - 1]; 876 877 /* Print the command if xflag is set. */ 878 if (xflag) 879 xtracecommand(&varlist, argc, argv); 880 881 /* Now locate the command. */ 882 if (argc == 0) { 883 /* Variable assignment(s) without command */ 884 cmdentry.cmdtype = CMDBUILTIN; 885 cmdentry.u.index = BLTINCMD; 886 cmdentry.special = 0; 887 } else { 888 static const char PATH[] = "PATH="; 889 int cmd_flags = 0, bltinonly = 0; 890 891 /* 892 * Modify the command lookup path, if a PATH= assignment 893 * is present 894 */ 895 for (i = 0; i < varlist.count; i++) 896 if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) { 897 path = varlist.args[i] + sizeof(PATH) - 1; 898 /* 899 * On `PATH=... command`, we need to make 900 * sure that the command isn't using the 901 * non-updated hash table of the outer PATH 902 * setting and we need to make sure that 903 * the hash table isn't filled with items 904 * from the temporary setting. 905 * 906 * It would be better to forbit using and 907 * updating the table while this command 908 * runs, by the command finding mechanism 909 * is heavily integrated with hash handling, 910 * so we just delete the hash before and after 911 * the command runs. Partly deleting like 912 * changepatch() does doesn't seem worth the 913 * bookinging effort, since most such runs add 914 * directories in front of the new PATH. 915 */ 916 clearcmdentry(); 917 do_clearcmdentry = 1; 918 } 919 920 for (;;) { 921 if (bltinonly) { 922 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 923 if (cmdentry.u.index < 0) { 924 cmdentry.u.index = BLTINCMD; 925 argv--; 926 argc++; 927 break; 928 } 929 } else 930 find_command(argv[0], &cmdentry, cmd_flags, path); 931 /* implement the bltin and command builtins here */ 932 if (cmdentry.cmdtype != CMDBUILTIN) 933 break; 934 if (cmdentry.u.index == BLTINCMD) { 935 if (argc == 1) 936 break; 937 argv++; 938 argc--; 939 bltinonly = 1; 940 } else if (cmdentry.u.index == COMMANDCMD) { 941 if (argc == 1) 942 break; 943 if (!strcmp(argv[1], "-p")) { 944 if (argc == 2) 945 break; 946 if (argv[2][0] == '-') { 947 if (strcmp(argv[2], "--")) 948 break; 949 if (argc == 3) 950 break; 951 argv += 3; 952 argc -= 3; 953 } else { 954 argv += 2; 955 argc -= 2; 956 } 957 path = _PATH_STDPATH; 958 clearcmdentry(); 959 do_clearcmdentry = 1; 960 } else if (!strcmp(argv[1], "--")) { 961 if (argc == 2) 962 break; 963 argv += 2; 964 argc -= 2; 965 } else if (argv[1][0] == '-') 966 break; 967 else { 968 argv++; 969 argc--; 970 } 971 cmd_flags |= DO_NOFUNC; 972 bltinonly = 0; 973 } else 974 break; 975 } 976 /* 977 * Special builtins lose their special properties when 978 * called via 'command'. 979 */ 980 if (cmd_flags & DO_NOFUNC) 981 cmdentry.special = 0; 982 } 983 984 /* Fork off a child process if necessary. */ 985 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 986 && ((flags & EV_EXIT) == 0 || have_traps())) 987 || ((flags & EV_BACKCMD) != 0 988 && (cmdentry.cmdtype != CMDBUILTIN || 989 !safe_builtin(cmdentry.u.index, argc, argv)))) { 990 jp = makejob(cmd, 1); 991 mode = FORK_FG; 992 if (flags & EV_BACKCMD) { 993 mode = FORK_NOJOB; 994 if (pipe(pip) < 0) 995 error("Pipe call failed: %s", strerror(errno)); 996 } 997 if (cmdentry.cmdtype == CMDNORMAL && 998 cmd->ncmd.redirect == NULL && 999 varlist.count == 0 && 1000 (mode == FORK_FG || mode == FORK_NOJOB) && 1001 !disvforkset() && !iflag && !mflag) { 1002 vforkexecshell(jp, argv, environment(), path, 1003 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL); 1004 goto parent; 1005 } 1006 if (forkshell(jp, cmd, mode) != 0) 1007 goto parent; /* at end of routine */ 1008 if (flags & EV_BACKCMD) { 1009 FORCEINTON; 1010 close(pip[0]); 1011 if (pip[1] != 1) { 1012 dup2(pip[1], 1); 1013 close(pip[1]); 1014 } 1015 flags &= ~EV_BACKCMD; 1016 } 1017 flags |= EV_EXIT; 1018 } 1019 1020 /* This is the child process if a fork occurred. */ 1021 /* Execute the command. */ 1022 if (cmdentry.cmdtype == CMDFUNCTION) { 1023 #ifdef DEBUG 1024 trputs("Shell function: "); trargs(argv); 1025 #endif 1026 saveparam = shellparam; 1027 shellparam.malloc = 0; 1028 shellparam.reset = 1; 1029 shellparam.nparam = argc - 1; 1030 shellparam.p = argv + 1; 1031 shellparam.optp = NULL; 1032 shellparam.optnext = NULL; 1033 INTOFF; 1034 savelocalvars = localvars; 1035 localvars = NULL; 1036 reffunc(cmdentry.u.func); 1037 savehandler = handler; 1038 if (setjmp(jmploc.loc)) { 1039 popredir(); 1040 unreffunc(cmdentry.u.func); 1041 poplocalvars(); 1042 localvars = savelocalvars; 1043 freeparam(&shellparam); 1044 shellparam = saveparam; 1045 funcnest--; 1046 handler = savehandler; 1047 longjmp(handler->loc, 1); 1048 } 1049 handler = &jmploc; 1050 funcnest++; 1051 redirect(cmd->ncmd.redirect, REDIR_PUSH); 1052 INTON; 1053 for (i = 0; i < varlist.count; i++) 1054 mklocal(varlist.args[i]); 1055 exitstatus = oexitstatus; 1056 evaltree(getfuncnode(cmdentry.u.func), 1057 flags & (EV_TESTED | EV_EXIT)); 1058 INTOFF; 1059 unreffunc(cmdentry.u.func); 1060 poplocalvars(); 1061 localvars = savelocalvars; 1062 freeparam(&shellparam); 1063 shellparam = saveparam; 1064 handler = savehandler; 1065 funcnest--; 1066 popredir(); 1067 INTON; 1068 if (evalskip == SKIPRETURN) { 1069 evalskip = 0; 1070 skipcount = 0; 1071 } 1072 if (jp) 1073 exitshell(exitstatus); 1074 } else if (cmdentry.cmdtype == CMDBUILTIN) { 1075 #ifdef DEBUG 1076 trputs("builtin command: "); trargs(argv); 1077 #endif 1078 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 1079 if (flags == EV_BACKCMD) { 1080 memout.nextc = memout.buf; 1081 mode |= REDIR_BACKQ; 1082 } 1083 savecmdname = commandname; 1084 savetopfile = getcurrentfile(); 1085 cmdenviron = &varlist; 1086 e = -1; 1087 savehandler = handler; 1088 if (setjmp(jmploc.loc)) { 1089 e = exception; 1090 if (e == EXINT) 1091 exitstatus = SIGINT+128; 1092 else if (e != EXEXIT) 1093 exitstatus = 2; 1094 goto cmddone; 1095 } 1096 handler = &jmploc; 1097 redirect(cmd->ncmd.redirect, mode); 1098 outclearerror(out1); 1099 /* 1100 * If there is no command word, redirection errors should 1101 * not be fatal but assignment errors should. 1102 */ 1103 if (argc == 0) 1104 cmdentry.special = 1; 1105 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1106 if (argc > 0) 1107 bltinsetlocale(); 1108 commandname = argv[0]; 1109 argptr = argv + 1; 1110 nextopt_optptr = NULL; /* initialize nextopt */ 1111 builtin_flags = flags; 1112 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1113 flushall(); 1114 if (outiserror(out1)) { 1115 warning("write error on stdout"); 1116 if (exitstatus == 0 || exitstatus == 1) 1117 exitstatus = 2; 1118 } 1119 cmddone: 1120 if (argc > 0) 1121 bltinunsetlocale(); 1122 cmdenviron = NULL; 1123 out1 = &output; 1124 out2 = &errout; 1125 freestdout(); 1126 handler = savehandler; 1127 commandname = savecmdname; 1128 if (jp) 1129 exitshell(exitstatus); 1130 if (flags == EV_BACKCMD) { 1131 backcmd->buf = memout.buf; 1132 backcmd->nleft = memout.buf != NULL ? 1133 memout.nextc - memout.buf : 0; 1134 memout.buf = NULL; 1135 memout.nextc = NULL; 1136 memout.bufend = NULL; 1137 memout.bufsize = 64; 1138 } 1139 if (cmdentry.u.index != EXECCMD) 1140 popredir(); 1141 if (e != -1) { 1142 if ((e != EXERROR && e != EXEXEC) 1143 || cmdentry.special) 1144 exraise(e); 1145 popfilesupto(savetopfile); 1146 if (flags != EV_BACKCMD) 1147 FORCEINTON; 1148 } 1149 } else { 1150 #ifdef DEBUG 1151 trputs("normal command: "); trargs(argv); 1152 #endif 1153 redirect(cmd->ncmd.redirect, 0); 1154 for (i = 0; i < varlist.count; i++) 1155 setvareq(varlist.args[i], VEXPORT|VSTACK); 1156 envp = environment(); 1157 shellexec(argv, envp, path, cmdentry.u.index); 1158 /*NOTREACHED*/ 1159 } 1160 goto out; 1161 1162 parent: /* parent process gets here (if we forked) */ 1163 if (mode == FORK_FG) { /* argument to fork */ 1164 INTOFF; 1165 exitstatus = waitforjob(jp, &signaled); 1166 INTON; 1167 if (iflag && loopnest > 0 && signaled) { 1168 evalskip = SKIPBREAK; 1169 skipcount = loopnest; 1170 } 1171 } else if (mode == FORK_NOJOB) { 1172 backcmd->fd = pip[0]; 1173 close(pip[1]); 1174 backcmd->jp = jp; 1175 } 1176 1177 out: 1178 if (lastarg) 1179 setvar("_", lastarg, 0); 1180 if (do_clearcmdentry) 1181 clearcmdentry(); 1182 } 1183 1184 1185 1186 /* 1187 * Search for a command. This is called before we fork so that the 1188 * location of the command will be available in the parent as well as 1189 * the child. The check for "goodname" is an overly conservative 1190 * check that the name will not be subject to expansion. 1191 */ 1192 1193 static void 1194 prehash(union node *n) 1195 { 1196 struct cmdentry entry; 1197 1198 if (n && n->type == NCMD && n->ncmd.args) 1199 if (goodname(n->ncmd.args->narg.text)) 1200 find_command(n->ncmd.args->narg.text, &entry, 0, 1201 pathval()); 1202 } 1203 1204 1205 1206 /* 1207 * Builtin commands. Builtin commands whose functions are closely 1208 * tied to evaluation are implemented here. 1209 */ 1210 1211 /* 1212 * No command given, a bltin command with no arguments, or a bltin command 1213 * with an invalid name. 1214 */ 1215 1216 int 1217 bltincmd(int argc, char **argv) 1218 { 1219 if (argc > 1) { 1220 out2fmt_flush("%s: not found\n", argv[1]); 1221 return 127; 1222 } 1223 /* 1224 * Preserve exitstatus of a previous possible command substitution 1225 * as POSIX mandates 1226 */ 1227 return exitstatus; 1228 } 1229 1230 1231 /* 1232 * Handle break and continue commands. Break, continue, and return are 1233 * all handled by setting the evalskip flag. The evaluation routines 1234 * above all check this flag, and if it is set they start skipping 1235 * commands rather than executing them. The variable skipcount is 1236 * the number of loops to break/continue, or the number of function 1237 * levels to return. (The latter is always 1.) It should probably 1238 * be an error to break out of more loops than exist, but it isn't 1239 * in the standard shell so we don't make it one here. 1240 */ 1241 1242 int 1243 breakcmd(int argc, char **argv) 1244 { 1245 long n; 1246 char *end; 1247 1248 if (argc > 1) { 1249 /* Allow arbitrarily large numbers. */ 1250 n = strtol(argv[1], &end, 10); 1251 if (!is_digit(argv[1][0]) || *end != '\0') 1252 error("Illegal number: %s", argv[1]); 1253 } else 1254 n = 1; 1255 if (n > loopnest) 1256 n = loopnest; 1257 if (n > 0) { 1258 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1259 skipcount = n; 1260 } 1261 return 0; 1262 } 1263 1264 /* 1265 * The `command' command. 1266 */ 1267 int 1268 commandcmd(int argc __unused, char **argv __unused) 1269 { 1270 const char *path; 1271 int ch; 1272 int cmd = -1; 1273 1274 path = bltinlookup("PATH", 1); 1275 1276 while ((ch = nextopt("pvV")) != '\0') { 1277 switch (ch) { 1278 case 'p': 1279 path = _PATH_STDPATH; 1280 break; 1281 case 'v': 1282 cmd = TYPECMD_SMALLV; 1283 break; 1284 case 'V': 1285 cmd = TYPECMD_BIGV; 1286 break; 1287 } 1288 } 1289 1290 if (cmd != -1) { 1291 if (*argptr == NULL || argptr[1] != NULL) 1292 error("wrong number of arguments"); 1293 return typecmd_impl(2, argptr - 1, cmd, path); 1294 } 1295 if (*argptr != NULL) 1296 error("commandcmd bad call"); 1297 1298 /* 1299 * Do nothing successfully if no command was specified; 1300 * ksh also does this. 1301 */ 1302 return 0; 1303 } 1304 1305 1306 /* 1307 * The return command. 1308 */ 1309 1310 int 1311 returncmd(int argc, char **argv) 1312 { 1313 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1314 1315 evalskip = SKIPRETURN; 1316 skipcount = 1; 1317 return ret; 1318 } 1319 1320 1321 int 1322 falsecmd(int argc __unused, char **argv __unused) 1323 { 1324 return 1; 1325 } 1326 1327 1328 int 1329 truecmd(int argc __unused, char **argv __unused) 1330 { 1331 return 0; 1332 } 1333 1334 1335 int 1336 execcmd(int argc, char **argv) 1337 { 1338 int i; 1339 1340 /* 1341 * Because we have historically not supported any options, 1342 * only treat "--" specially. 1343 */ 1344 if (argc > 1 && strcmp(argv[1], "--") == 0) 1345 argc--, argv++; 1346 if (argc > 1) { 1347 iflag = 0; /* exit on error */ 1348 mflag = 0; 1349 optschanged(); 1350 for (i = 0; i < cmdenviron->count; i++) 1351 setvareq(cmdenviron->args[i], VEXPORT|VSTACK); 1352 shellexec(argv + 1, environment(), pathval(), 0); 1353 1354 } 1355 return 0; 1356 } 1357 1358 1359 int 1360 timescmd(int argc __unused, char **argv __unused) 1361 { 1362 struct rusage ru; 1363 long shumins, shsmins, chumins, chsmins; 1364 double shusecs, shssecs, chusecs, chssecs; 1365 1366 if (getrusage(RUSAGE_SELF, &ru) < 0) 1367 return 1; 1368 shumins = ru.ru_utime.tv_sec / 60; 1369 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1370 shsmins = ru.ru_stime.tv_sec / 60; 1371 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1372 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1373 return 1; 1374 chumins = ru.ru_utime.tv_sec / 60; 1375 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1376 chsmins = ru.ru_stime.tv_sec / 60; 1377 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1378 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1379 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1380 return 0; 1381 } 1382