1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #ifndef lint 34 #if 0 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 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; 499 500 redir->nhere.expdoc = ""; 501 savelocalvars = localvars; 502 localvars = NULL; 503 forcelocal++; 504 savehandler = handler; 505 if (setjmp(jmploc.loc)) 506 need_longjmp = exception != EXERROR && exception != EXEXEC; 507 else { 508 handler = &jmploc; 509 expandarg(redir->nhere.doc, fn, 0); 510 redir->nhere.expdoc = fn->args[0]; 511 INTOFF; 512 } 513 handler = savehandler; 514 forcelocal--; 515 poplocalvars(); 516 localvars = savelocalvars; 517 if (need_longjmp) 518 longjmp(handler->loc, 1); 519 INTON; 520 } 521 522 523 /* 524 * Compute the names of the files in a redirection list. 525 */ 526 527 static void 528 expredir(union node *n) 529 { 530 union node *redir; 531 532 for (redir = n ; redir ; redir = redir->nfile.next) { 533 struct arglist fn; 534 emptyarglist(&fn); 535 switch (redir->type) { 536 case NFROM: 537 case NTO: 538 case NFROMTO: 539 case NAPPEND: 540 case NCLOBBER: 541 expandarg(redir->nfile.fname, &fn, EXP_TILDE); 542 redir->nfile.expfname = fn.args[0]; 543 break; 544 case NFROMFD: 545 case NTOFD: 546 if (redir->ndup.vname) { 547 expandarg(redir->ndup.vname, &fn, EXP_TILDE); 548 fixredir(redir, fn.args[0], 1); 549 } 550 break; 551 case NXHERE: 552 exphere(redir, &fn); 553 break; 554 } 555 } 556 } 557 558 559 560 /* 561 * Evaluate a pipeline. All the processes in the pipeline are children 562 * of the process creating the pipeline. (This differs from some versions 563 * of the shell, which make the last process in a pipeline the parent 564 * of all the rest.) 565 */ 566 567 static void 568 evalpipe(union node *n) 569 { 570 struct job *jp; 571 struct nodelist *lp; 572 int pipelen; 573 int prevfd; 574 int pip[2]; 575 576 TRACE(("evalpipe(%p) called\n", (void *)n)); 577 pipelen = 0; 578 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 579 pipelen++; 580 INTOFF; 581 jp = makejob(n, pipelen); 582 prevfd = -1; 583 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 584 prehash(lp->n); 585 pip[1] = -1; 586 if (lp->next) { 587 if (pipe(pip) < 0) { 588 if (prevfd >= 0) 589 close(prevfd); 590 error("Pipe call failed: %s", strerror(errno)); 591 } 592 } 593 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 594 INTON; 595 if (prevfd > 0) { 596 dup2(prevfd, 0); 597 close(prevfd); 598 } 599 if (pip[1] >= 0) { 600 if (!(prevfd >= 0 && pip[0] == 0)) 601 close(pip[0]); 602 if (pip[1] != 1) { 603 dup2(pip[1], 1); 604 close(pip[1]); 605 } 606 } 607 evaltree(lp->n, EV_EXIT); 608 } 609 if (prevfd >= 0) 610 close(prevfd); 611 prevfd = pip[0]; 612 if (pip[1] != -1) 613 close(pip[1]); 614 } 615 INTON; 616 if (n->npipe.backgnd == 0) { 617 INTOFF; 618 exitstatus = waitforjob(jp, (int *)NULL); 619 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 620 INTON; 621 } else 622 exitstatus = 0; 623 } 624 625 626 627 static int 628 is_valid_fast_cmdsubst(union node *n) 629 { 630 631 return (n->type == NCMD); 632 } 633 634 /* 635 * Execute a command inside back quotes. If it's a builtin command, we 636 * want to save its output in a block obtained from malloc. Otherwise 637 * we fork off a subprocess and get the output of the command via a pipe. 638 * Should be called with interrupts off. 639 */ 640 641 void 642 evalbackcmd(union node *n, struct backcmd *result) 643 { 644 int pip[2]; 645 struct job *jp; 646 struct stackmark smark; 647 struct jmploc jmploc; 648 struct jmploc *savehandler; 649 struct localvar *savelocalvars; 650 651 result->fd = -1; 652 result->buf = NULL; 653 result->nleft = 0; 654 result->jp = NULL; 655 if (n == NULL) { 656 exitstatus = 0; 657 return; 658 } 659 setstackmark(&smark); 660 exitstatus = oexitstatus; 661 if (is_valid_fast_cmdsubst(n)) { 662 savelocalvars = localvars; 663 localvars = NULL; 664 forcelocal++; 665 savehandler = handler; 666 if (setjmp(jmploc.loc)) { 667 if (exception == EXERROR || exception == EXEXEC) 668 exitstatus = 2; 669 else if (exception != 0) { 670 handler = savehandler; 671 forcelocal--; 672 poplocalvars(); 673 localvars = savelocalvars; 674 longjmp(handler->loc, 1); 675 } 676 } else { 677 handler = &jmploc; 678 evalcommand(n, EV_BACKCMD, result); 679 } 680 handler = savehandler; 681 forcelocal--; 682 poplocalvars(); 683 localvars = savelocalvars; 684 } else { 685 if (pipe(pip) < 0) 686 error("Pipe call failed: %s", strerror(errno)); 687 jp = makejob(n, 1); 688 if (forkshell(jp, n, FORK_NOJOB) == 0) { 689 FORCEINTON; 690 close(pip[0]); 691 if (pip[1] != 1) { 692 dup2(pip[1], 1); 693 close(pip[1]); 694 } 695 evaltree(n, EV_EXIT); 696 } 697 close(pip[1]); 698 result->fd = pip[0]; 699 result->jp = jp; 700 } 701 popstackmark(&smark); 702 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 703 result->fd, result->buf, result->nleft, result->jp)); 704 } 705 706 static int 707 mustexpandto(const char *argtext, const char *mask) 708 { 709 for (;;) { 710 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) { 711 argtext++; 712 continue; 713 } 714 if (*argtext == CTLESC) 715 argtext++; 716 else if (BASESYNTAX[(int)*argtext] == CCTL) 717 return (0); 718 if (*argtext != *mask) 719 return (0); 720 if (*argtext == '\0') 721 return (1); 722 argtext++; 723 mask++; 724 } 725 } 726 727 static int 728 isdeclarationcmd(struct narg *arg) 729 { 730 int have_command = 0; 731 732 if (arg == NULL) 733 return (0); 734 while (mustexpandto(arg->text, "command")) { 735 have_command = 1; 736 arg = &arg->next->narg; 737 if (arg == NULL) 738 return (0); 739 /* 740 * To also allow "command -p" and "command --" as part of 741 * a declaration command, add code here. 742 * We do not do this, as ksh does not do it either and it 743 * is not required by POSIX. 744 */ 745 } 746 return (mustexpandto(arg->text, "export") || 747 mustexpandto(arg->text, "readonly") || 748 (mustexpandto(arg->text, "local") && 749 (have_command || !isfunc("local")))); 750 } 751 752 static void 753 xtracecommand(struct arglist *varlist, int argc, char **argv) 754 { 755 char sep = 0; 756 const char *text, *p, *ps4; 757 int i; 758 759 ps4 = expandstr(ps4val()); 760 out2str(ps4 != NULL ? ps4 : ps4val()); 761 for (i = 0; i < varlist->count; i++) { 762 text = varlist->args[i]; 763 if (sep != 0) 764 out2c(' '); 765 p = strchr(text, '='); 766 if (p != NULL) { 767 p++; 768 outbin(text, p - text, out2); 769 out2qstr(p); 770 } else 771 out2qstr(text); 772 sep = ' '; 773 } 774 for (i = 0; i < argc; i++) { 775 text = argv[i]; 776 if (sep != 0) 777 out2c(' '); 778 out2qstr(text); 779 sep = ' '; 780 } 781 out2c('\n'); 782 flushout(&errout); 783 } 784 785 /* 786 * Check if a builtin can safely be executed in the same process, 787 * even though it should be in a subshell (command substitution). 788 * Note that jobid, jobs, times and trap can show information not 789 * available in a child process; this is deliberate. 790 * The arguments should already have been expanded. 791 */ 792 static int 793 safe_builtin(int idx, int argc, char **argv) 794 { 795 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 796 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 797 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 798 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 799 idx == TYPECMD) 800 return (1); 801 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 802 idx == UMASKCMD) 803 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 804 if (idx == SETCMD) 805 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 806 argv[1][0] == '+') && argv[1][1] == 'o' && 807 argv[1][2] == '\0')); 808 return (0); 809 } 810 811 /* 812 * Execute a simple command. 813 * Note: This may or may not return if (flags & EV_EXIT). 814 */ 815 816 static void 817 evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 818 { 819 union node *argp; 820 struct arglist arglist; 821 struct arglist varlist; 822 char **argv; 823 int argc; 824 char **envp; 825 int varflag; 826 int mode; 827 int pip[2]; 828 struct cmdentry cmdentry; 829 struct job *jp; 830 struct jmploc jmploc; 831 struct jmploc *savehandler; 832 char *savecmdname; 833 struct shparam saveparam; 834 struct localvar *savelocalvars; 835 struct parsefile *savetopfile; 836 volatile int e; 837 char *lastarg; 838 int realstatus; 839 int do_clearcmdentry; 840 const char *path = pathval(); 841 int i; 842 843 /* First expand the arguments. */ 844 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 845 emptyarglist(&arglist); 846 emptyarglist(&varlist); 847 varflag = 1; 848 jp = NULL; 849 do_clearcmdentry = 0; 850 oexitstatus = exitstatus; 851 exitstatus = 0; 852 /* Add one slot at the beginning for tryexec(). */ 853 appendarglist(&arglist, nullstr); 854 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 855 if (varflag && isassignment(argp->narg.text)) { 856 expandarg(argp, varflag == 1 ? &varlist : &arglist, 857 EXP_VARTILDE); 858 continue; 859 } else if (varflag == 1) 860 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0; 861 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 862 } 863 appendarglist(&arglist, nullstr); 864 expredir(cmd->ncmd.redirect); 865 argc = arglist.count - 2; 866 argv = &arglist.args[1]; 867 868 argv[argc] = NULL; 869 lastarg = NULL; 870 if (iflag && funcnest == 0 && argc > 0) 871 lastarg = argv[argc - 1]; 872 873 /* Print the command if xflag is set. */ 874 if (xflag) 875 xtracecommand(&varlist, argc, argv); 876 877 /* Now locate the command. */ 878 if (argc == 0) { 879 /* Variable assignment(s) without command */ 880 cmdentry.cmdtype = CMDBUILTIN; 881 cmdentry.u.index = BLTINCMD; 882 cmdentry.special = 0; 883 } else { 884 static const char PATH[] = "PATH="; 885 int cmd_flags = 0, bltinonly = 0; 886 887 /* 888 * Modify the command lookup path, if a PATH= assignment 889 * is present 890 */ 891 for (i = 0; i < varlist.count; i++) 892 if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) { 893 path = varlist.args[i] + sizeof(PATH) - 1; 894 /* 895 * On `PATH=... command`, we need to make 896 * sure that the command isn't using the 897 * non-updated hash table of the outer PATH 898 * setting and we need to make sure that 899 * the hash table isn't filled with items 900 * from the temporary setting. 901 * 902 * It would be better to forbit using and 903 * updating the table while this command 904 * runs, by the command finding mechanism 905 * is heavily integrated with hash handling, 906 * so we just delete the hash before and after 907 * the command runs. Partly deleting like 908 * changepatch() does doesn't seem worth the 909 * bookinging effort, since most such runs add 910 * directories in front of the new PATH. 911 */ 912 clearcmdentry(); 913 do_clearcmdentry = 1; 914 } 915 916 for (;;) { 917 if (bltinonly) { 918 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 919 if (cmdentry.u.index < 0) { 920 cmdentry.u.index = BLTINCMD; 921 argv--; 922 argc++; 923 break; 924 } 925 } else 926 find_command(argv[0], &cmdentry, cmd_flags, path); 927 /* implement the bltin and command builtins here */ 928 if (cmdentry.cmdtype != CMDBUILTIN) 929 break; 930 if (cmdentry.u.index == BLTINCMD) { 931 if (argc == 1) 932 break; 933 argv++; 934 argc--; 935 bltinonly = 1; 936 } else if (cmdentry.u.index == COMMANDCMD) { 937 if (argc == 1) 938 break; 939 if (!strcmp(argv[1], "-p")) { 940 if (argc == 2) 941 break; 942 if (argv[2][0] == '-') { 943 if (strcmp(argv[2], "--")) 944 break; 945 if (argc == 3) 946 break; 947 argv += 3; 948 argc -= 3; 949 } else { 950 argv += 2; 951 argc -= 2; 952 } 953 path = _PATH_STDPATH; 954 clearcmdentry(); 955 do_clearcmdentry = 1; 956 } else if (!strcmp(argv[1], "--")) { 957 if (argc == 2) 958 break; 959 argv += 2; 960 argc -= 2; 961 } else if (argv[1][0] == '-') 962 break; 963 else { 964 argv++; 965 argc--; 966 } 967 cmd_flags |= DO_NOFUNC; 968 bltinonly = 0; 969 } else 970 break; 971 } 972 /* 973 * Special builtins lose their special properties when 974 * called via 'command'. 975 */ 976 if (cmd_flags & DO_NOFUNC) 977 cmdentry.special = 0; 978 } 979 980 /* Fork off a child process if necessary. */ 981 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 982 && ((flags & EV_EXIT) == 0 || have_traps())) 983 || ((flags & EV_BACKCMD) != 0 984 && (cmdentry.cmdtype != CMDBUILTIN || 985 !safe_builtin(cmdentry.u.index, argc, argv)))) { 986 jp = makejob(cmd, 1); 987 mode = FORK_FG; 988 if (flags & EV_BACKCMD) { 989 mode = FORK_NOJOB; 990 if (pipe(pip) < 0) 991 error("Pipe call failed: %s", strerror(errno)); 992 } 993 if (cmdentry.cmdtype == CMDNORMAL && 994 cmd->ncmd.redirect == NULL && 995 varlist.count == 0 && 996 (mode == FORK_FG || mode == FORK_NOJOB) && 997 !disvforkset() && !iflag && !mflag) { 998 vforkexecshell(jp, argv, environment(), path, 999 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL); 1000 goto parent; 1001 } 1002 if (forkshell(jp, cmd, mode) != 0) 1003 goto parent; /* at end of routine */ 1004 if (flags & EV_BACKCMD) { 1005 FORCEINTON; 1006 close(pip[0]); 1007 if (pip[1] != 1) { 1008 dup2(pip[1], 1); 1009 close(pip[1]); 1010 } 1011 flags &= ~EV_BACKCMD; 1012 } 1013 flags |= EV_EXIT; 1014 } 1015 1016 /* This is the child process if a fork occurred. */ 1017 /* Execute the command. */ 1018 if (cmdentry.cmdtype == CMDFUNCTION) { 1019 #ifdef DEBUG 1020 trputs("Shell function: "); trargs(argv); 1021 #endif 1022 saveparam = shellparam; 1023 shellparam.malloc = 0; 1024 shellparam.reset = 1; 1025 shellparam.nparam = argc - 1; 1026 shellparam.p = argv + 1; 1027 shellparam.optp = NULL; 1028 shellparam.optnext = NULL; 1029 INTOFF; 1030 savelocalvars = localvars; 1031 localvars = NULL; 1032 reffunc(cmdentry.u.func); 1033 savehandler = handler; 1034 if (setjmp(jmploc.loc)) { 1035 freeparam(&shellparam); 1036 shellparam = saveparam; 1037 popredir(); 1038 unreffunc(cmdentry.u.func); 1039 poplocalvars(); 1040 localvars = savelocalvars; 1041 funcnest--; 1042 handler = savehandler; 1043 longjmp(handler->loc, 1); 1044 } 1045 handler = &jmploc; 1046 funcnest++; 1047 redirect(cmd->ncmd.redirect, REDIR_PUSH); 1048 INTON; 1049 for (i = 0; i < varlist.count; i++) 1050 mklocal(varlist.args[i]); 1051 exitstatus = oexitstatus; 1052 evaltree(getfuncnode(cmdentry.u.func), 1053 flags & (EV_TESTED | EV_EXIT)); 1054 INTOFF; 1055 unreffunc(cmdentry.u.func); 1056 poplocalvars(); 1057 localvars = savelocalvars; 1058 freeparam(&shellparam); 1059 shellparam = saveparam; 1060 handler = savehandler; 1061 funcnest--; 1062 popredir(); 1063 INTON; 1064 if (evalskip == SKIPRETURN) { 1065 evalskip = 0; 1066 skipcount = 0; 1067 } 1068 if (jp) 1069 exitshell(exitstatus); 1070 } else if (cmdentry.cmdtype == CMDBUILTIN) { 1071 #ifdef DEBUG 1072 trputs("builtin command: "); trargs(argv); 1073 #endif 1074 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 1075 if (flags == EV_BACKCMD) { 1076 memout.nleft = 0; 1077 memout.nextc = memout.buf; 1078 memout.bufsize = 64; 1079 mode |= REDIR_BACKQ; 1080 } 1081 savecmdname = commandname; 1082 savetopfile = getcurrentfile(); 1083 cmdenviron = &varlist; 1084 e = -1; 1085 savehandler = handler; 1086 if (setjmp(jmploc.loc)) { 1087 e = exception; 1088 if (e == EXINT) 1089 exitstatus = SIGINT+128; 1090 else if (e != EXEXIT) 1091 exitstatus = 2; 1092 goto cmddone; 1093 } 1094 handler = &jmploc; 1095 redirect(cmd->ncmd.redirect, mode); 1096 outclearerror(out1); 1097 /* 1098 * If there is no command word, redirection errors should 1099 * not be fatal but assignment errors should. 1100 */ 1101 if (argc == 0) 1102 cmdentry.special = 1; 1103 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1104 if (argc > 0) 1105 bltinsetlocale(); 1106 commandname = argv[0]; 1107 argptr = argv + 1; 1108 nextopt_optptr = NULL; /* initialize nextopt */ 1109 builtin_flags = flags; 1110 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1111 flushall(); 1112 if (outiserror(out1)) { 1113 warning("write error on stdout"); 1114 if (exitstatus == 0 || exitstatus == 1) 1115 exitstatus = 2; 1116 } 1117 cmddone: 1118 if (argc > 0) 1119 bltinunsetlocale(); 1120 cmdenviron = NULL; 1121 out1 = &output; 1122 out2 = &errout; 1123 freestdout(); 1124 handler = savehandler; 1125 commandname = savecmdname; 1126 if (jp) 1127 exitshell(exitstatus); 1128 if (flags == EV_BACKCMD) { 1129 backcmd->buf = memout.buf; 1130 backcmd->nleft = memout.nextc - memout.buf; 1131 memout.buf = NULL; 1132 } 1133 if (cmdentry.u.index != EXECCMD) 1134 popredir(); 1135 if (e != -1) { 1136 if ((e != EXERROR && e != EXEXEC) 1137 || cmdentry.special) 1138 exraise(e); 1139 popfilesupto(savetopfile); 1140 if (flags != EV_BACKCMD) 1141 FORCEINTON; 1142 } 1143 } else { 1144 #ifdef DEBUG 1145 trputs("normal command: "); trargs(argv); 1146 #endif 1147 redirect(cmd->ncmd.redirect, 0); 1148 for (i = 0; i < varlist.count; i++) 1149 setvareq(varlist.args[i], VEXPORT|VSTACK); 1150 envp = environment(); 1151 shellexec(argv, envp, path, cmdentry.u.index); 1152 /*NOTREACHED*/ 1153 } 1154 goto out; 1155 1156 parent: /* parent process gets here (if we forked) */ 1157 if (mode == FORK_FG) { /* argument to fork */ 1158 INTOFF; 1159 exitstatus = waitforjob(jp, &realstatus); 1160 INTON; 1161 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1162 evalskip = SKIPBREAK; 1163 skipcount = loopnest; 1164 } 1165 } else if (mode == FORK_NOJOB) { 1166 backcmd->fd = pip[0]; 1167 close(pip[1]); 1168 backcmd->jp = jp; 1169 } 1170 1171 out: 1172 if (lastarg) 1173 setvar("_", lastarg, 0); 1174 if (do_clearcmdentry) 1175 clearcmdentry(); 1176 } 1177 1178 1179 1180 /* 1181 * Search for a command. This is called before we fork so that the 1182 * location of the command will be available in the parent as well as 1183 * the child. The check for "goodname" is an overly conservative 1184 * check that the name will not be subject to expansion. 1185 */ 1186 1187 static void 1188 prehash(union node *n) 1189 { 1190 struct cmdentry entry; 1191 1192 if (n && n->type == NCMD && n->ncmd.args) 1193 if (goodname(n->ncmd.args->narg.text)) 1194 find_command(n->ncmd.args->narg.text, &entry, 0, 1195 pathval()); 1196 } 1197 1198 1199 1200 /* 1201 * Builtin commands. Builtin commands whose functions are closely 1202 * tied to evaluation are implemented here. 1203 */ 1204 1205 /* 1206 * No command given, a bltin command with no arguments, or a bltin command 1207 * with an invalid name. 1208 */ 1209 1210 int 1211 bltincmd(int argc, char **argv) 1212 { 1213 if (argc > 1) { 1214 out2fmt_flush("%s: not found\n", argv[1]); 1215 return 127; 1216 } 1217 /* 1218 * Preserve exitstatus of a previous possible redirection 1219 * as POSIX mandates 1220 */ 1221 return exitstatus; 1222 } 1223 1224 1225 /* 1226 * Handle break and continue commands. Break, continue, and return are 1227 * all handled by setting the evalskip flag. The evaluation routines 1228 * above all check this flag, and if it is set they start skipping 1229 * commands rather than executing them. The variable skipcount is 1230 * the number of loops to break/continue, or the number of function 1231 * levels to return. (The latter is always 1.) It should probably 1232 * be an error to break out of more loops than exist, but it isn't 1233 * in the standard shell so we don't make it one here. 1234 */ 1235 1236 int 1237 breakcmd(int argc, char **argv) 1238 { 1239 long n; 1240 char *end; 1241 1242 if (argc > 1) { 1243 /* Allow arbitrarily large numbers. */ 1244 n = strtol(argv[1], &end, 10); 1245 if (!is_digit(argv[1][0]) || *end != '\0') 1246 error("Illegal number: %s", argv[1]); 1247 } else 1248 n = 1; 1249 if (n > loopnest) 1250 n = loopnest; 1251 if (n > 0) { 1252 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1253 skipcount = n; 1254 } 1255 return 0; 1256 } 1257 1258 /* 1259 * The `command' command. 1260 */ 1261 int 1262 commandcmd(int argc __unused, char **argv __unused) 1263 { 1264 const char *path; 1265 int ch; 1266 int cmd = -1; 1267 1268 path = bltinlookup("PATH", 1); 1269 1270 while ((ch = nextopt("pvV")) != '\0') { 1271 switch (ch) { 1272 case 'p': 1273 path = _PATH_STDPATH; 1274 break; 1275 case 'v': 1276 cmd = TYPECMD_SMALLV; 1277 break; 1278 case 'V': 1279 cmd = TYPECMD_BIGV; 1280 break; 1281 } 1282 } 1283 1284 if (cmd != -1) { 1285 if (*argptr == NULL || argptr[1] != NULL) 1286 error("wrong number of arguments"); 1287 return typecmd_impl(2, argptr - 1, cmd, path); 1288 } 1289 if (*argptr != NULL) 1290 error("commandcmd bad call"); 1291 1292 /* 1293 * Do nothing successfully if no command was specified; 1294 * ksh also does this. 1295 */ 1296 return 0; 1297 } 1298 1299 1300 /* 1301 * The return command. 1302 */ 1303 1304 int 1305 returncmd(int argc, char **argv) 1306 { 1307 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1308 1309 evalskip = SKIPRETURN; 1310 skipcount = 1; 1311 return ret; 1312 } 1313 1314 1315 int 1316 falsecmd(int argc __unused, char **argv __unused) 1317 { 1318 return 1; 1319 } 1320 1321 1322 int 1323 truecmd(int argc __unused, char **argv __unused) 1324 { 1325 return 0; 1326 } 1327 1328 1329 int 1330 execcmd(int argc, char **argv) 1331 { 1332 int i; 1333 1334 /* 1335 * Because we have historically not supported any options, 1336 * only treat "--" specially. 1337 */ 1338 if (argc > 1 && strcmp(argv[1], "--") == 0) 1339 argc--, argv++; 1340 if (argc > 1) { 1341 iflag = 0; /* exit on error */ 1342 mflag = 0; 1343 optschanged(); 1344 for (i = 0; i < cmdenviron->count; i++) 1345 setvareq(cmdenviron->args[i], VEXPORT|VSTACK); 1346 shellexec(argv + 1, environment(), pathval(), 0); 1347 1348 } 1349 return 0; 1350 } 1351 1352 1353 int 1354 timescmd(int argc __unused, char **argv __unused) 1355 { 1356 struct rusage ru; 1357 long shumins, shsmins, chumins, chsmins; 1358 double shusecs, shssecs, chusecs, chssecs; 1359 1360 if (getrusage(RUSAGE_SELF, &ru) < 0) 1361 return 1; 1362 shumins = ru.ru_utime.tv_sec / 60; 1363 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1364 shsmins = ru.ru_stime.tv_sec / 60; 1365 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1366 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1367 return 1; 1368 chumins = ru.ru_utime.tv_sec / 60; 1369 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1370 chsmins = ru.ru_stime.tv_sec / 60; 1371 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1372 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1373 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1374 return 0; 1375 } 1376