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 <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 77 int evalskip; /* set if we are skipping commands */ 78 int skipcount; /* number of levels to skip */ 79 static int loopnest; /* current loop nesting level */ 80 int funcnest; /* depth of function calls */ 81 static int builtin_flags; /* evalcommand flags for builtins */ 82 83 84 char *commandname; 85 struct arglist *cmdenviron; 86 int exitstatus; /* exit status of last command */ 87 int oexitstatus; /* saved exit status */ 88 89 90 static void evalloop(union node *, int); 91 static void evalfor(union node *, int); 92 static union node *evalcase(union node *); 93 static void evalsubshell(union node *, int); 94 static void evalredir(union node *, int); 95 static void exphere(union node *, struct arglist *); 96 static void expredir(union node *); 97 static void evalpipe(union node *); 98 static int is_valid_fast_cmdsubst(union node *n); 99 static void evalcommand(union node *, int, struct backcmd *); 100 static void prehash(union node *); 101 102 103 /* 104 * Called to reset things after an exception. 105 */ 106 107 void 108 reseteval(void) 109 { 110 evalskip = 0; 111 loopnest = 0; 112 } 113 114 115 /* 116 * The eval command. 117 */ 118 119 int 120 evalcmd(int argc, char **argv) 121 { 122 char *p; 123 char *concat; 124 char **ap; 125 126 if (argc > 1) { 127 p = argv[1]; 128 if (argc > 2) { 129 STARTSTACKSTR(concat); 130 ap = argv + 2; 131 for (;;) { 132 STPUTS(p, concat); 133 if ((p = *ap++) == NULL) 134 break; 135 STPUTC(' ', concat); 136 } 137 STPUTC('\0', concat); 138 p = grabstackstr(concat); 139 } 140 evalstring(p, builtin_flags); 141 } else 142 exitstatus = 0; 143 return exitstatus; 144 } 145 146 147 /* 148 * Execute a command or commands contained in a string. 149 */ 150 151 void 152 evalstring(const char *s, int flags) 153 { 154 union node *n; 155 struct stackmark smark; 156 int flags_exit; 157 int any; 158 159 flags_exit = flags & EV_EXIT; 160 flags &= ~EV_EXIT; 161 any = 0; 162 setstackmark(&smark); 163 setinputstring(s, 1); 164 while ((n = parsecmd(0)) != NEOF) { 165 if (n != NULL && !nflag) { 166 if (flags_exit && preadateof()) 167 evaltree(n, flags | EV_EXIT); 168 else 169 evaltree(n, flags); 170 any = 1; 171 if (evalskip) 172 break; 173 } 174 popstackmark(&smark); 175 setstackmark(&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 */ 190 191 void 192 evaltree(union node *n, int flags) 193 { 194 int do_etest; 195 union node *next; 196 struct stackmark smark; 197 198 setstackmark(&smark); 199 do_etest = 0; 200 if (n == NULL) { 201 TRACE(("evaltree(NULL) called\n")); 202 exitstatus = 0; 203 goto out; 204 } 205 do { 206 next = NULL; 207 #ifndef NO_HISTORY 208 displayhist = 1; /* show history substitutions done with fc */ 209 #endif 210 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 211 switch (n->type) { 212 case NSEMI: 213 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 214 if (evalskip) 215 goto out; 216 next = n->nbinary.ch2; 217 break; 218 case NAND: 219 evaltree(n->nbinary.ch1, EV_TESTED); 220 if (evalskip || exitstatus != 0) { 221 goto out; 222 } 223 next = n->nbinary.ch2; 224 break; 225 case NOR: 226 evaltree(n->nbinary.ch1, EV_TESTED); 227 if (evalskip || exitstatus == 0) 228 goto out; 229 next = n->nbinary.ch2; 230 break; 231 case NREDIR: 232 evalredir(n, flags); 233 break; 234 case NSUBSHELL: 235 evalsubshell(n, flags); 236 do_etest = !(flags & EV_TESTED); 237 break; 238 case NBACKGND: 239 evalsubshell(n, flags); 240 break; 241 case NIF: { 242 evaltree(n->nif.test, EV_TESTED); 243 if (evalskip) 244 goto out; 245 if (exitstatus == 0) 246 next = n->nif.ifpart; 247 else if (n->nif.elsepart) 248 next = n->nif.elsepart; 249 else 250 exitstatus = 0; 251 break; 252 } 253 case NWHILE: 254 case NUNTIL: 255 evalloop(n, flags & ~EV_EXIT); 256 break; 257 case NFOR: 258 evalfor(n, flags & ~EV_EXIT); 259 break; 260 case NCASE: 261 next = evalcase(n); 262 break; 263 case NCLIST: 264 next = n->nclist.body; 265 break; 266 case NCLISTFALLTHRU: 267 if (n->nclist.body) { 268 evaltree(n->nclist.body, flags & ~EV_EXIT); 269 if (evalskip) 270 goto out; 271 } 272 next = n->nclist.next; 273 break; 274 case NDEFUN: 275 defun(n->narg.text, n->narg.next); 276 exitstatus = 0; 277 break; 278 case NNOT: 279 evaltree(n->nnot.com, EV_TESTED); 280 if (evalskip) 281 goto out; 282 exitstatus = !exitstatus; 283 break; 284 285 case NPIPE: 286 evalpipe(n); 287 do_etest = !(flags & EV_TESTED); 288 break; 289 case NCMD: 290 evalcommand(n, flags, (struct backcmd *)NULL); 291 do_etest = !(flags & EV_TESTED); 292 break; 293 default: 294 out1fmt("Node type = %d\n", n->type); 295 flushout(&output); 296 break; 297 } 298 n = next; 299 popstackmark(&smark); 300 setstackmark(&smark); 301 } while (n != NULL); 302 out: 303 popstackmark(&smark); 304 if (pendingsig) 305 dotrap(); 306 if (eflag && exitstatus != 0 && do_etest) 307 exitshell(exitstatus); 308 if (flags & EV_EXIT) 309 exraise(EXEXIT); 310 } 311 312 313 static void 314 evalloop(union node *n, int flags) 315 { 316 int status; 317 318 loopnest++; 319 status = 0; 320 for (;;) { 321 if (!evalskip) 322 evaltree(n->nbinary.ch1, EV_TESTED); 323 if (evalskip) { 324 if (evalskip == SKIPCONT && --skipcount <= 0) { 325 evalskip = 0; 326 continue; 327 } 328 if (evalskip == SKIPBREAK && --skipcount <= 0) 329 evalskip = 0; 330 if (evalskip == SKIPRETURN) 331 status = exitstatus; 332 break; 333 } 334 if (n->type == NWHILE) { 335 if (exitstatus != 0) 336 break; 337 } else { 338 if (exitstatus == 0) 339 break; 340 } 341 evaltree(n->nbinary.ch2, flags); 342 status = exitstatus; 343 } 344 loopnest--; 345 exitstatus = status; 346 } 347 348 349 350 static void 351 evalfor(union node *n, int flags) 352 { 353 struct arglist arglist; 354 union node *argp; 355 int i; 356 int status; 357 358 emptyarglist(&arglist); 359 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 360 oexitstatus = exitstatus; 361 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 362 } 363 364 loopnest++; 365 status = 0; 366 for (i = 0; i < arglist.count; i++) { 367 setvar(n->nfor.var, arglist.args[i], 0); 368 evaltree(n->nfor.body, flags); 369 status = exitstatus; 370 if (evalskip) { 371 if (evalskip == SKIPCONT && --skipcount <= 0) { 372 evalskip = 0; 373 continue; 374 } 375 if (evalskip == SKIPBREAK && --skipcount <= 0) 376 evalskip = 0; 377 break; 378 } 379 } 380 loopnest--; 381 exitstatus = status; 382 } 383 384 385 /* 386 * Evaluate a case statement, returning the selected tree. 387 * 388 * The exit status needs care to get right. 389 */ 390 391 static union node * 392 evalcase(union node *n) 393 { 394 union node *cp; 395 union node *patp; 396 struct arglist arglist; 397 398 emptyarglist(&arglist); 399 oexitstatus = exitstatus; 400 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 401 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) { 402 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 403 if (casematch(patp, arglist.args[0])) { 404 while (cp->nclist.next && 405 cp->type == NCLISTFALLTHRU && 406 cp->nclist.body == NULL) 407 cp = cp->nclist.next; 408 if (cp->nclist.next && 409 cp->type == NCLISTFALLTHRU) 410 return (cp); 411 if (cp->nclist.body == NULL) 412 exitstatus = 0; 413 return (cp->nclist.body); 414 } 415 } 416 } 417 exitstatus = 0; 418 return (NULL); 419 } 420 421 422 423 /* 424 * Kick off a subshell to evaluate a tree. 425 */ 426 427 static void 428 evalsubshell(union node *n, int flags) 429 { 430 struct job *jp; 431 int backgnd = (n->type == NBACKGND); 432 433 oexitstatus = exitstatus; 434 expredir(n->nredir.redirect); 435 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 436 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 437 if (backgnd) 438 flags &=~ EV_TESTED; 439 redirect(n->nredir.redirect, 0); 440 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 441 } else if (! backgnd) { 442 INTOFF; 443 exitstatus = waitforjob(jp, (int *)NULL); 444 INTON; 445 } else 446 exitstatus = 0; 447 } 448 449 450 /* 451 * Evaluate a redirected compound command. 452 */ 453 454 static void 455 evalredir(union node *n, int flags) 456 { 457 struct jmploc jmploc; 458 struct jmploc *savehandler; 459 volatile int in_redirect = 1; 460 461 oexitstatus = exitstatus; 462 expredir(n->nredir.redirect); 463 savehandler = handler; 464 if (setjmp(jmploc.loc)) { 465 int e; 466 467 handler = savehandler; 468 e = exception; 469 popredir(); 470 if (e == EXERROR || e == EXEXEC) { 471 if (in_redirect) { 472 exitstatus = 2; 473 FORCEINTON; 474 return; 475 } 476 } 477 longjmp(handler->loc, 1); 478 } else { 479 INTOFF; 480 handler = &jmploc; 481 redirect(n->nredir.redirect, REDIR_PUSH); 482 in_redirect = 0; 483 INTON; 484 evaltree(n->nredir.n, flags); 485 } 486 INTOFF; 487 handler = savehandler; 488 popredir(); 489 INTON; 490 } 491 492 493 static void 494 exphere(union node *redir, struct arglist *fn) 495 { 496 struct jmploc jmploc; 497 struct jmploc *savehandler; 498 struct localvar *savelocalvars; 499 int need_longjmp = 0; 500 unsigned char saveoptreset; 501 502 redir->nhere.expdoc = ""; 503 savelocalvars = localvars; 504 localvars = NULL; 505 saveoptreset = shellparam.reset; 506 forcelocal++; 507 savehandler = handler; 508 if (setjmp(jmploc.loc)) 509 need_longjmp = exception != EXERROR && exception != EXEXEC; 510 else { 511 handler = &jmploc; 512 expandarg(redir->nhere.doc, fn, 0); 513 redir->nhere.expdoc = fn->args[0]; 514 INTOFF; 515 } 516 handler = savehandler; 517 forcelocal--; 518 poplocalvars(); 519 localvars = savelocalvars; 520 shellparam.reset = saveoptreset; 521 if (need_longjmp) 522 longjmp(handler->loc, 1); 523 INTON; 524 } 525 526 527 /* 528 * Compute the names of the files in a redirection list. 529 */ 530 531 static void 532 expredir(union node *n) 533 { 534 union node *redir; 535 536 for (redir = n ; redir ; redir = redir->nfile.next) { 537 struct arglist fn; 538 emptyarglist(&fn); 539 switch (redir->type) { 540 case NFROM: 541 case NTO: 542 case NFROMTO: 543 case NAPPEND: 544 case NCLOBBER: 545 expandarg(redir->nfile.fname, &fn, EXP_TILDE); 546 redir->nfile.expfname = fn.args[0]; 547 break; 548 case NFROMFD: 549 case NTOFD: 550 if (redir->ndup.vname) { 551 expandarg(redir->ndup.vname, &fn, EXP_TILDE); 552 fixredir(redir, fn.args[0], 1); 553 } 554 break; 555 case NXHERE: 556 exphere(redir, &fn); 557 break; 558 } 559 } 560 } 561 562 563 564 /* 565 * Evaluate a pipeline. All the processes in the pipeline are children 566 * of the process creating the pipeline. (This differs from some versions 567 * of the shell, which make the last process in a pipeline the parent 568 * of all the rest.) 569 */ 570 571 static void 572 evalpipe(union node *n) 573 { 574 struct job *jp; 575 struct nodelist *lp; 576 int pipelen; 577 int prevfd; 578 int pip[2]; 579 580 TRACE(("evalpipe(%p) called\n", (void *)n)); 581 pipelen = 0; 582 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 583 pipelen++; 584 INTOFF; 585 jp = makejob(n, pipelen); 586 prevfd = -1; 587 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 588 prehash(lp->n); 589 pip[1] = -1; 590 if (lp->next) { 591 if (pipe(pip) < 0) { 592 if (prevfd >= 0) 593 close(prevfd); 594 error("Pipe call failed: %s", strerror(errno)); 595 } 596 } 597 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 598 INTON; 599 if (prevfd > 0) { 600 dup2(prevfd, 0); 601 close(prevfd); 602 } 603 if (pip[1] >= 0) { 604 if (!(prevfd >= 0 && pip[0] == 0)) 605 close(pip[0]); 606 if (pip[1] != 1) { 607 dup2(pip[1], 1); 608 close(pip[1]); 609 } 610 } 611 evaltree(lp->n, EV_EXIT); 612 } 613 if (prevfd >= 0) 614 close(prevfd); 615 prevfd = pip[0]; 616 if (pip[1] != -1) 617 close(pip[1]); 618 } 619 INTON; 620 if (n->npipe.backgnd == 0) { 621 INTOFF; 622 exitstatus = waitforjob(jp, (int *)NULL); 623 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 624 INTON; 625 } else 626 exitstatus = 0; 627 } 628 629 630 631 static int 632 is_valid_fast_cmdsubst(union node *n) 633 { 634 635 return (n->type == NCMD); 636 } 637 638 /* 639 * Execute a command inside back quotes. If it's a builtin command, we 640 * want to save its output in a block obtained from malloc. Otherwise 641 * we fork off a subprocess and get the output of the command via a pipe. 642 * Should be called with interrupts off. 643 */ 644 645 void 646 evalbackcmd(union node *n, struct backcmd *result) 647 { 648 int pip[2]; 649 struct job *jp; 650 struct stackmark smark; 651 struct jmploc jmploc; 652 struct jmploc *savehandler; 653 struct localvar *savelocalvars; 654 unsigned char saveoptreset; 655 656 result->fd = -1; 657 result->buf = NULL; 658 result->nleft = 0; 659 result->jp = NULL; 660 if (n == NULL) { 661 exitstatus = 0; 662 return; 663 } 664 setstackmark(&smark); 665 exitstatus = oexitstatus; 666 if (is_valid_fast_cmdsubst(n)) { 667 savelocalvars = localvars; 668 localvars = NULL; 669 saveoptreset = shellparam.reset; 670 forcelocal++; 671 savehandler = handler; 672 if (setjmp(jmploc.loc)) { 673 if (exception == EXERROR || exception == EXEXEC) 674 exitstatus = 2; 675 else if (exception != 0) { 676 handler = savehandler; 677 forcelocal--; 678 poplocalvars(); 679 localvars = savelocalvars; 680 shellparam.reset = saveoptreset; 681 longjmp(handler->loc, 1); 682 } 683 } else { 684 handler = &jmploc; 685 evalcommand(n, EV_BACKCMD, result); 686 } 687 handler = savehandler; 688 forcelocal--; 689 poplocalvars(); 690 localvars = savelocalvars; 691 shellparam.reset = saveoptreset; 692 } else { 693 if (pipe(pip) < 0) 694 error("Pipe call failed: %s", strerror(errno)); 695 jp = makejob(n, 1); 696 if (forkshell(jp, n, FORK_NOJOB) == 0) { 697 FORCEINTON; 698 close(pip[0]); 699 if (pip[1] != 1) { 700 dup2(pip[1], 1); 701 close(pip[1]); 702 } 703 evaltree(n, EV_EXIT); 704 } 705 close(pip[1]); 706 result->fd = pip[0]; 707 result->jp = jp; 708 } 709 popstackmark(&smark); 710 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 711 result->fd, result->buf, result->nleft, result->jp)); 712 } 713 714 static int 715 mustexpandto(const char *argtext, const char *mask) 716 { 717 for (;;) { 718 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) { 719 argtext++; 720 continue; 721 } 722 if (*argtext == CTLESC) 723 argtext++; 724 else if (BASESYNTAX[(int)*argtext] == CCTL) 725 return (0); 726 if (*argtext != *mask) 727 return (0); 728 if (*argtext == '\0') 729 return (1); 730 argtext++; 731 mask++; 732 } 733 } 734 735 static int 736 isdeclarationcmd(struct narg *arg) 737 { 738 int have_command = 0; 739 740 if (arg == NULL) 741 return (0); 742 while (mustexpandto(arg->text, "command")) { 743 have_command = 1; 744 arg = &arg->next->narg; 745 if (arg == NULL) 746 return (0); 747 /* 748 * To also allow "command -p" and "command --" as part of 749 * a declaration command, add code here. 750 * We do not do this, as ksh does not do it either and it 751 * is not required by POSIX. 752 */ 753 } 754 return (mustexpandto(arg->text, "export") || 755 mustexpandto(arg->text, "readonly") || 756 (mustexpandto(arg->text, "local") && 757 (have_command || !isfunc("local")))); 758 } 759 760 static void 761 xtracecommand(struct arglist *varlist, int argc, char **argv) 762 { 763 char sep = 0; 764 const char *text, *p, *ps4; 765 int i; 766 767 ps4 = expandstr(ps4val()); 768 out2str(ps4 != NULL ? ps4 : ps4val()); 769 for (i = 0; i < varlist->count; i++) { 770 text = varlist->args[i]; 771 if (sep != 0) 772 out2c(' '); 773 p = strchr(text, '='); 774 if (p != NULL) { 775 p++; 776 outbin(text, p - text, out2); 777 out2qstr(p); 778 } else 779 out2qstr(text); 780 sep = ' '; 781 } 782 for (i = 0; i < argc; i++) { 783 text = argv[i]; 784 if (sep != 0) 785 out2c(' '); 786 out2qstr(text); 787 sep = ' '; 788 } 789 out2c('\n'); 790 flushout(&errout); 791 } 792 793 /* 794 * Check if a builtin can safely be executed in the same process, 795 * even though it should be in a subshell (command substitution). 796 * Note that jobid, jobs, times and trap can show information not 797 * available in a child process; this is deliberate. 798 * The arguments should already have been expanded. 799 */ 800 static int 801 safe_builtin(int idx, int argc, char **argv) 802 { 803 /* Generated from builtins.def. */ 804 if (safe_builtin_always(idx)) 805 return (1); 806 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 807 idx == UMASKCMD) 808 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 809 if (idx == SETCMD) 810 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 811 argv[1][0] == '+') && argv[1][1] == 'o' && 812 argv[1][2] == '\0')); 813 return (0); 814 } 815 816 /* 817 * Execute a simple command. 818 * Note: This may or may not return if (flags & EV_EXIT). 819 */ 820 821 static void 822 evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 823 { 824 union node *argp; 825 struct arglist arglist; 826 struct arglist varlist; 827 char **argv; 828 int argc; 829 char **envp; 830 int varflag; 831 int mode; 832 int pip[2]; 833 struct cmdentry cmdentry; 834 struct job *jp; 835 struct jmploc jmploc; 836 struct jmploc *savehandler; 837 char *savecmdname; 838 struct shparam saveparam; 839 struct localvar *savelocalvars; 840 struct parsefile *savetopfile; 841 volatile int e; 842 char *lastarg; 843 int realstatus; 844 int do_clearcmdentry; 845 const char *path = pathval(); 846 int i; 847 848 /* First expand the arguments. */ 849 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 850 emptyarglist(&arglist); 851 emptyarglist(&varlist); 852 varflag = 1; 853 jp = NULL; 854 do_clearcmdentry = 0; 855 oexitstatus = exitstatus; 856 exitstatus = 0; 857 /* Add one slot at the beginning for tryexec(). */ 858 appendarglist(&arglist, nullstr); 859 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 860 if (varflag && isassignment(argp->narg.text)) { 861 expandarg(argp, varflag == 1 ? &varlist : &arglist, 862 EXP_VARTILDE); 863 continue; 864 } else if (varflag == 1) 865 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0; 866 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 867 } 868 appendarglist(&arglist, nullstr); 869 expredir(cmd->ncmd.redirect); 870 argc = arglist.count - 2; 871 argv = &arglist.args[1]; 872 873 argv[argc] = NULL; 874 lastarg = NULL; 875 if (iflag && funcnest == 0 && argc > 0) 876 lastarg = argv[argc - 1]; 877 878 /* Print the command if xflag is set. */ 879 if (xflag) 880 xtracecommand(&varlist, argc, argv); 881 882 /* Now locate the command. */ 883 if (argc == 0) { 884 /* Variable assignment(s) without command */ 885 cmdentry.cmdtype = CMDBUILTIN; 886 cmdentry.u.index = BLTINCMD; 887 cmdentry.special = 0; 888 } else { 889 static const char PATH[] = "PATH="; 890 int cmd_flags = 0, bltinonly = 0; 891 892 /* 893 * Modify the command lookup path, if a PATH= assignment 894 * is present 895 */ 896 for (i = 0; i < varlist.count; i++) 897 if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) { 898 path = varlist.args[i] + sizeof(PATH) - 1; 899 /* 900 * On `PATH=... command`, we need to make 901 * sure that the command isn't using the 902 * non-updated hash table of the outer PATH 903 * setting and we need to make sure that 904 * the hash table isn't filled with items 905 * from the temporary setting. 906 * 907 * It would be better to forbit using and 908 * updating the table while this command 909 * runs, by the command finding mechanism 910 * is heavily integrated with hash handling, 911 * so we just delete the hash before and after 912 * the command runs. Partly deleting like 913 * changepatch() does doesn't seem worth the 914 * bookinging effort, since most such runs add 915 * directories in front of the new PATH. 916 */ 917 clearcmdentry(); 918 do_clearcmdentry = 1; 919 } 920 921 for (;;) { 922 if (bltinonly) { 923 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 924 if (cmdentry.u.index < 0) { 925 cmdentry.u.index = BLTINCMD; 926 argv--; 927 argc++; 928 break; 929 } 930 } else 931 find_command(argv[0], &cmdentry, cmd_flags, path); 932 /* implement the bltin and command builtins here */ 933 if (cmdentry.cmdtype != CMDBUILTIN) 934 break; 935 if (cmdentry.u.index == BLTINCMD) { 936 if (argc == 1) 937 break; 938 argv++; 939 argc--; 940 bltinonly = 1; 941 } else if (cmdentry.u.index == COMMANDCMD) { 942 if (argc == 1) 943 break; 944 if (!strcmp(argv[1], "-p")) { 945 if (argc == 2) 946 break; 947 if (argv[2][0] == '-') { 948 if (strcmp(argv[2], "--")) 949 break; 950 if (argc == 3) 951 break; 952 argv += 3; 953 argc -= 3; 954 } else { 955 argv += 2; 956 argc -= 2; 957 } 958 path = _PATH_STDPATH; 959 clearcmdentry(); 960 do_clearcmdentry = 1; 961 } else if (!strcmp(argv[1], "--")) { 962 if (argc == 2) 963 break; 964 argv += 2; 965 argc -= 2; 966 } else if (argv[1][0] == '-') 967 break; 968 else { 969 argv++; 970 argc--; 971 } 972 cmd_flags |= DO_NOFUNC; 973 bltinonly = 0; 974 } else 975 break; 976 } 977 /* 978 * Special builtins lose their special properties when 979 * called via 'command'. 980 */ 981 if (cmd_flags & DO_NOFUNC) 982 cmdentry.special = 0; 983 } 984 985 /* Fork off a child process if necessary. */ 986 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 987 && ((flags & EV_EXIT) == 0 || have_traps())) 988 || ((flags & EV_BACKCMD) != 0 989 && (cmdentry.cmdtype != CMDBUILTIN || 990 !safe_builtin(cmdentry.u.index, argc, argv)))) { 991 jp = makejob(cmd, 1); 992 mode = FORK_FG; 993 if (flags & EV_BACKCMD) { 994 mode = FORK_NOJOB; 995 if (pipe(pip) < 0) 996 error("Pipe call failed: %s", strerror(errno)); 997 } 998 if (cmdentry.cmdtype == CMDNORMAL && 999 cmd->ncmd.redirect == NULL && 1000 varlist.count == 0 && 1001 (mode == FORK_FG || mode == FORK_NOJOB) && 1002 !disvforkset() && !iflag && !mflag) { 1003 vforkexecshell(jp, argv, environment(), path, 1004 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL); 1005 goto parent; 1006 } 1007 if (forkshell(jp, cmd, mode) != 0) 1008 goto parent; /* at end of routine */ 1009 if (flags & EV_BACKCMD) { 1010 FORCEINTON; 1011 close(pip[0]); 1012 if (pip[1] != 1) { 1013 dup2(pip[1], 1); 1014 close(pip[1]); 1015 } 1016 flags &= ~EV_BACKCMD; 1017 } 1018 flags |= EV_EXIT; 1019 } 1020 1021 /* This is the child process if a fork occurred. */ 1022 /* Execute the command. */ 1023 if (cmdentry.cmdtype == CMDFUNCTION) { 1024 #ifdef DEBUG 1025 trputs("Shell function: "); trargs(argv); 1026 #endif 1027 saveparam = shellparam; 1028 shellparam.malloc = 0; 1029 shellparam.reset = 1; 1030 shellparam.nparam = argc - 1; 1031 shellparam.p = argv + 1; 1032 shellparam.optp = NULL; 1033 shellparam.optnext = NULL; 1034 INTOFF; 1035 savelocalvars = localvars; 1036 localvars = NULL; 1037 reffunc(cmdentry.u.func); 1038 savehandler = handler; 1039 if (setjmp(jmploc.loc)) { 1040 popredir(); 1041 unreffunc(cmdentry.u.func); 1042 poplocalvars(); 1043 localvars = savelocalvars; 1044 freeparam(&shellparam); 1045 shellparam = saveparam; 1046 funcnest--; 1047 handler = savehandler; 1048 longjmp(handler->loc, 1); 1049 } 1050 handler = &jmploc; 1051 funcnest++; 1052 redirect(cmd->ncmd.redirect, REDIR_PUSH); 1053 INTON; 1054 for (i = 0; i < varlist.count; i++) 1055 mklocal(varlist.args[i]); 1056 exitstatus = oexitstatus; 1057 evaltree(getfuncnode(cmdentry.u.func), 1058 flags & (EV_TESTED | EV_EXIT)); 1059 INTOFF; 1060 unreffunc(cmdentry.u.func); 1061 poplocalvars(); 1062 localvars = savelocalvars; 1063 freeparam(&shellparam); 1064 shellparam = saveparam; 1065 handler = savehandler; 1066 funcnest--; 1067 popredir(); 1068 INTON; 1069 if (evalskip == SKIPRETURN) { 1070 evalskip = 0; 1071 skipcount = 0; 1072 } 1073 if (jp) 1074 exitshell(exitstatus); 1075 } else if (cmdentry.cmdtype == CMDBUILTIN) { 1076 #ifdef DEBUG 1077 trputs("builtin command: "); trargs(argv); 1078 #endif 1079 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 1080 if (flags == EV_BACKCMD) { 1081 memout.nextc = memout.buf; 1082 mode |= REDIR_BACKQ; 1083 } 1084 savecmdname = commandname; 1085 savetopfile = getcurrentfile(); 1086 cmdenviron = &varlist; 1087 e = -1; 1088 savehandler = handler; 1089 if (setjmp(jmploc.loc)) { 1090 e = exception; 1091 if (e == EXINT) 1092 exitstatus = SIGINT+128; 1093 else if (e != EXEXIT) 1094 exitstatus = 2; 1095 goto cmddone; 1096 } 1097 handler = &jmploc; 1098 redirect(cmd->ncmd.redirect, mode); 1099 outclearerror(out1); 1100 /* 1101 * If there is no command word, redirection errors should 1102 * not be fatal but assignment errors should. 1103 */ 1104 if (argc == 0) 1105 cmdentry.special = 1; 1106 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1107 if (argc > 0) 1108 bltinsetlocale(); 1109 commandname = argv[0]; 1110 argptr = argv + 1; 1111 nextopt_optptr = NULL; /* initialize nextopt */ 1112 builtin_flags = flags; 1113 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1114 flushall(); 1115 if (outiserror(out1)) { 1116 warning("write error on stdout"); 1117 if (exitstatus == 0 || exitstatus == 1) 1118 exitstatus = 2; 1119 } 1120 cmddone: 1121 if (argc > 0) 1122 bltinunsetlocale(); 1123 cmdenviron = NULL; 1124 out1 = &output; 1125 out2 = &errout; 1126 freestdout(); 1127 handler = savehandler; 1128 commandname = savecmdname; 1129 if (jp) 1130 exitshell(exitstatus); 1131 if (flags == EV_BACKCMD) { 1132 backcmd->buf = memout.buf; 1133 backcmd->nleft = memout.buf != NULL ? 1134 memout.nextc - memout.buf : 0; 1135 memout.buf = NULL; 1136 memout.nextc = NULL; 1137 memout.bufend = NULL; 1138 memout.bufsize = 64; 1139 } 1140 if (cmdentry.u.index != EXECCMD) 1141 popredir(); 1142 if (e != -1) { 1143 if ((e != EXERROR && e != EXEXEC) 1144 || cmdentry.special) 1145 exraise(e); 1146 popfilesupto(savetopfile); 1147 if (flags != EV_BACKCMD) 1148 FORCEINTON; 1149 } 1150 } else { 1151 #ifdef DEBUG 1152 trputs("normal command: "); trargs(argv); 1153 #endif 1154 redirect(cmd->ncmd.redirect, 0); 1155 for (i = 0; i < varlist.count; i++) 1156 setvareq(varlist.args[i], VEXPORT|VSTACK); 1157 envp = environment(); 1158 shellexec(argv, envp, path, cmdentry.u.index); 1159 /*NOTREACHED*/ 1160 } 1161 goto out; 1162 1163 parent: /* parent process gets here (if we forked) */ 1164 if (mode == FORK_FG) { /* argument to fork */ 1165 INTOFF; 1166 exitstatus = waitforjob(jp, &realstatus); 1167 INTON; 1168 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1169 evalskip = SKIPBREAK; 1170 skipcount = loopnest; 1171 } 1172 } else if (mode == FORK_NOJOB) { 1173 backcmd->fd = pip[0]; 1174 close(pip[1]); 1175 backcmd->jp = jp; 1176 } 1177 1178 out: 1179 if (lastarg) 1180 setvar("_", lastarg, 0); 1181 if (do_clearcmdentry) 1182 clearcmdentry(); 1183 } 1184 1185 1186 1187 /* 1188 * Search for a command. This is called before we fork so that the 1189 * location of the command will be available in the parent as well as 1190 * the child. The check for "goodname" is an overly conservative 1191 * check that the name will not be subject to expansion. 1192 */ 1193 1194 static void 1195 prehash(union node *n) 1196 { 1197 struct cmdentry entry; 1198 1199 if (n && n->type == NCMD && n->ncmd.args) 1200 if (goodname(n->ncmd.args->narg.text)) 1201 find_command(n->ncmd.args->narg.text, &entry, 0, 1202 pathval()); 1203 } 1204 1205 1206 1207 /* 1208 * Builtin commands. Builtin commands whose functions are closely 1209 * tied to evaluation are implemented here. 1210 */ 1211 1212 /* 1213 * No command given, a bltin command with no arguments, or a bltin command 1214 * with an invalid name. 1215 */ 1216 1217 int 1218 bltincmd(int argc, char **argv) 1219 { 1220 if (argc > 1) { 1221 out2fmt_flush("%s: not found\n", argv[1]); 1222 return 127; 1223 } 1224 /* 1225 * Preserve exitstatus of a previous possible command substitution 1226 * as POSIX mandates 1227 */ 1228 return exitstatus; 1229 } 1230 1231 1232 /* 1233 * Handle break and continue commands. Break, continue, and return are 1234 * all handled by setting the evalskip flag. The evaluation routines 1235 * above all check this flag, and if it is set they start skipping 1236 * commands rather than executing them. The variable skipcount is 1237 * the number of loops to break/continue, or the number of function 1238 * levels to return. (The latter is always 1.) It should probably 1239 * be an error to break out of more loops than exist, but it isn't 1240 * in the standard shell so we don't make it one here. 1241 */ 1242 1243 int 1244 breakcmd(int argc, char **argv) 1245 { 1246 long n; 1247 char *end; 1248 1249 if (argc > 1) { 1250 /* Allow arbitrarily large numbers. */ 1251 n = strtol(argv[1], &end, 10); 1252 if (!is_digit(argv[1][0]) || *end != '\0') 1253 error("Illegal number: %s", argv[1]); 1254 } else 1255 n = 1; 1256 if (n > loopnest) 1257 n = loopnest; 1258 if (n > 0) { 1259 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1260 skipcount = n; 1261 } 1262 return 0; 1263 } 1264 1265 /* 1266 * The `command' command. 1267 */ 1268 int 1269 commandcmd(int argc __unused, char **argv __unused) 1270 { 1271 const char *path; 1272 int ch; 1273 int cmd = -1; 1274 1275 path = bltinlookup("PATH", 1); 1276 1277 while ((ch = nextopt("pvV")) != '\0') { 1278 switch (ch) { 1279 case 'p': 1280 path = _PATH_STDPATH; 1281 break; 1282 case 'v': 1283 cmd = TYPECMD_SMALLV; 1284 break; 1285 case 'V': 1286 cmd = TYPECMD_BIGV; 1287 break; 1288 } 1289 } 1290 1291 if (cmd != -1) { 1292 if (*argptr == NULL || argptr[1] != NULL) 1293 error("wrong number of arguments"); 1294 return typecmd_impl(2, argptr - 1, cmd, path); 1295 } 1296 if (*argptr != NULL) 1297 error("commandcmd bad call"); 1298 1299 /* 1300 * Do nothing successfully if no command was specified; 1301 * ksh also does this. 1302 */ 1303 return 0; 1304 } 1305 1306 1307 /* 1308 * The return command. 1309 */ 1310 1311 int 1312 returncmd(int argc, char **argv) 1313 { 1314 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1315 1316 evalskip = SKIPRETURN; 1317 skipcount = 1; 1318 return ret; 1319 } 1320 1321 1322 int 1323 falsecmd(int argc __unused, char **argv __unused) 1324 { 1325 return 1; 1326 } 1327 1328 1329 int 1330 truecmd(int argc __unused, char **argv __unused) 1331 { 1332 return 0; 1333 } 1334 1335 1336 int 1337 execcmd(int argc, char **argv) 1338 { 1339 int i; 1340 1341 /* 1342 * Because we have historically not supported any options, 1343 * only treat "--" specially. 1344 */ 1345 if (argc > 1 && strcmp(argv[1], "--") == 0) 1346 argc--, argv++; 1347 if (argc > 1) { 1348 iflag = 0; /* exit on error */ 1349 mflag = 0; 1350 optschanged(); 1351 for (i = 0; i < cmdenviron->count; i++) 1352 setvareq(cmdenviron->args[i], VEXPORT|VSTACK); 1353 shellexec(argv + 1, environment(), pathval(), 0); 1354 1355 } 1356 return 0; 1357 } 1358 1359 1360 int 1361 timescmd(int argc __unused, char **argv __unused) 1362 { 1363 struct rusage ru; 1364 long shumins, shsmins, chumins, chsmins; 1365 double shusecs, shssecs, chusecs, chssecs; 1366 1367 if (getrusage(RUSAGE_SELF, &ru) < 0) 1368 return 1; 1369 shumins = ru.ru_utime.tv_sec / 60; 1370 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1371 shsmins = ru.ru_stime.tv_sec / 60; 1372 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1373 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1374 return 1; 1375 chumins = ru.ru_utime.tv_sec / 60; 1376 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1377 chsmins = ru.ru_stime.tv_sec / 60; 1378 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1379 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1380 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1381 return 0; 1382 } 1383