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 strlist *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(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 } 172 popstackmark(&smark); 173 setstackmark(&smark); 174 } 175 popfile(); 176 popstackmark(&smark); 177 if (!any) 178 exitstatus = 0; 179 if (flags_exit) 180 exraise(EXEXIT); 181 } 182 183 184 /* 185 * Evaluate a parse tree. The value is left in the global variable 186 * exitstatus. 187 */ 188 189 void 190 evaltree(union node *n, int flags) 191 { 192 int do_etest; 193 union node *next; 194 struct stackmark smark; 195 196 setstackmark(&smark); 197 do_etest = 0; 198 if (n == NULL) { 199 TRACE(("evaltree(NULL) called\n")); 200 exitstatus = 0; 201 goto out; 202 } 203 do { 204 next = NULL; 205 #ifndef NO_HISTORY 206 displayhist = 1; /* show history substitutions done with fc */ 207 #endif 208 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 209 switch (n->type) { 210 case NSEMI: 211 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 212 if (evalskip) 213 goto out; 214 next = n->nbinary.ch2; 215 break; 216 case NAND: 217 evaltree(n->nbinary.ch1, EV_TESTED); 218 if (evalskip || exitstatus != 0) { 219 goto out; 220 } 221 next = n->nbinary.ch2; 222 break; 223 case NOR: 224 evaltree(n->nbinary.ch1, EV_TESTED); 225 if (evalskip || exitstatus == 0) 226 goto out; 227 next = n->nbinary.ch2; 228 break; 229 case NREDIR: 230 evalredir(n, flags); 231 break; 232 case NSUBSHELL: 233 evalsubshell(n, flags); 234 do_etest = !(flags & EV_TESTED); 235 break; 236 case NBACKGND: 237 evalsubshell(n, flags); 238 break; 239 case NIF: { 240 evaltree(n->nif.test, EV_TESTED); 241 if (evalskip) 242 goto out; 243 if (exitstatus == 0) 244 next = n->nif.ifpart; 245 else if (n->nif.elsepart) 246 next = n->nif.elsepart; 247 else 248 exitstatus = 0; 249 break; 250 } 251 case NWHILE: 252 case NUNTIL: 253 evalloop(n, flags & ~EV_EXIT); 254 break; 255 case NFOR: 256 evalfor(n, flags & ~EV_EXIT); 257 break; 258 case NCASE: 259 next = evalcase(n); 260 break; 261 case NCLIST: 262 next = n->nclist.body; 263 break; 264 case NCLISTFALLTHRU: 265 if (n->nclist.body) { 266 evaltree(n->nclist.body, flags & ~EV_EXIT); 267 if (evalskip) 268 goto out; 269 } 270 next = n->nclist.next; 271 break; 272 case NDEFUN: 273 defun(n->narg.text, n->narg.next); 274 exitstatus = 0; 275 break; 276 case NNOT: 277 evaltree(n->nnot.com, EV_TESTED); 278 if (evalskip) 279 goto out; 280 exitstatus = !exitstatus; 281 break; 282 283 case NPIPE: 284 evalpipe(n); 285 do_etest = !(flags & EV_TESTED); 286 break; 287 case NCMD: 288 evalcommand(n, flags, (struct backcmd *)NULL); 289 do_etest = !(flags & EV_TESTED); 290 break; 291 default: 292 out1fmt("Node type = %d\n", n->type); 293 flushout(&output); 294 break; 295 } 296 n = next; 297 popstackmark(&smark); 298 setstackmark(&smark); 299 } while (n != NULL); 300 out: 301 popstackmark(&smark); 302 if (pendingsig) 303 dotrap(); 304 if (eflag && exitstatus != 0 && do_etest) 305 exitshell(exitstatus); 306 if (flags & EV_EXIT) 307 exraise(EXEXIT); 308 } 309 310 311 static void 312 evalloop(union node *n, int flags) 313 { 314 int status; 315 316 loopnest++; 317 status = 0; 318 for (;;) { 319 if (!evalskip) 320 evaltree(n->nbinary.ch1, EV_TESTED); 321 if (evalskip) { 322 if (evalskip == SKIPCONT && --skipcount <= 0) { 323 evalskip = 0; 324 continue; 325 } 326 if (evalskip == SKIPBREAK && --skipcount <= 0) 327 evalskip = 0; 328 if (evalskip == SKIPRETURN) 329 status = exitstatus; 330 break; 331 } 332 if (n->type == NWHILE) { 333 if (exitstatus != 0) 334 break; 335 } else { 336 if (exitstatus == 0) 337 break; 338 } 339 evaltree(n->nbinary.ch2, flags); 340 status = exitstatus; 341 } 342 loopnest--; 343 exitstatus = status; 344 } 345 346 347 348 static void 349 evalfor(union node *n, int flags) 350 { 351 struct arglist arglist; 352 union node *argp; 353 struct strlist *sp; 354 int status; 355 356 arglist.lastp = &arglist.list; 357 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 358 oexitstatus = exitstatus; 359 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 360 } 361 *arglist.lastp = NULL; 362 363 loopnest++; 364 status = 0; 365 for (sp = arglist.list ; sp ; sp = sp->next) { 366 setvar(n->nfor.var, sp->text, 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 arglist.lastp = &arglist.list; 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.list->text)) { 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 return; 473 } 474 } 475 longjmp(handler->loc, 1); 476 } else { 477 INTOFF; 478 handler = &jmploc; 479 redirect(n->nredir.redirect, REDIR_PUSH); 480 in_redirect = 0; 481 INTON; 482 evaltree(n->nredir.n, flags); 483 } 484 INTOFF; 485 handler = savehandler; 486 popredir(); 487 INTON; 488 } 489 490 491 static void 492 exphere(union node *redir, struct arglist *fn) 493 { 494 struct jmploc jmploc; 495 struct jmploc *savehandler; 496 struct localvar *savelocalvars; 497 int need_longjmp = 0; 498 499 redir->nhere.expdoc = nullstr; 500 savelocalvars = localvars; 501 localvars = NULL; 502 forcelocal++; 503 savehandler = handler; 504 if (setjmp(jmploc.loc)) 505 need_longjmp = exception != EXERROR && exception != EXEXEC; 506 else { 507 handler = &jmploc; 508 expandarg(redir->nhere.doc, fn, 0); 509 redir->nhere.expdoc = fn->list->text; 510 INTOFF; 511 } 512 handler = savehandler; 513 forcelocal--; 514 poplocalvars(); 515 localvars = savelocalvars; 516 if (need_longjmp) 517 longjmp(handler->loc, 1); 518 INTON; 519 } 520 521 522 /* 523 * Compute the names of the files in a redirection list. 524 */ 525 526 static void 527 expredir(union node *n) 528 { 529 union node *redir; 530 531 for (redir = n ; redir ; redir = redir->nfile.next) { 532 struct arglist fn; 533 fn.lastp = &fn.list; 534 switch (redir->type) { 535 case NFROM: 536 case NTO: 537 case NFROMTO: 538 case NAPPEND: 539 case NCLOBBER: 540 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 541 redir->nfile.expfname = fn.list->text; 542 break; 543 case NFROMFD: 544 case NTOFD: 545 if (redir->ndup.vname) { 546 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 547 fixredir(redir, fn.list->text, 1); 548 } 549 break; 550 case NXHERE: 551 exphere(redir, &fn); 552 break; 553 } 554 } 555 } 556 557 558 559 /* 560 * Evaluate a pipeline. All the processes in the pipeline are children 561 * of the process creating the pipeline. (This differs from some versions 562 * of the shell, which make the last process in a pipeline the parent 563 * of all the rest.) 564 */ 565 566 static void 567 evalpipe(union node *n) 568 { 569 struct job *jp; 570 struct nodelist *lp; 571 int pipelen; 572 int prevfd; 573 int pip[2]; 574 575 TRACE(("evalpipe(%p) called\n", (void *)n)); 576 pipelen = 0; 577 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 578 pipelen++; 579 INTOFF; 580 jp = makejob(n, pipelen); 581 prevfd = -1; 582 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 583 prehash(lp->n); 584 pip[1] = -1; 585 if (lp->next) { 586 if (pipe(pip) < 0) { 587 if (prevfd >= 0) 588 close(prevfd); 589 error("Pipe call failed: %s", strerror(errno)); 590 } 591 } 592 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 593 INTON; 594 if (prevfd > 0) { 595 dup2(prevfd, 0); 596 close(prevfd); 597 } 598 if (pip[1] >= 0) { 599 if (!(prevfd >= 0 && pip[0] == 0)) 600 close(pip[0]); 601 if (pip[1] != 1) { 602 dup2(pip[1], 1); 603 close(pip[1]); 604 } 605 } 606 evaltree(lp->n, EV_EXIT); 607 } 608 if (prevfd >= 0) 609 close(prevfd); 610 prevfd = pip[0]; 611 if (pip[1] != -1) 612 close(pip[1]); 613 } 614 INTON; 615 if (n->npipe.backgnd == 0) { 616 INTOFF; 617 exitstatus = waitforjob(jp, (int *)NULL); 618 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 619 INTON; 620 } else 621 exitstatus = 0; 622 } 623 624 625 626 static int 627 is_valid_fast_cmdsubst(union node *n) 628 { 629 630 return (n->type == NCMD); 631 } 632 633 /* 634 * Execute a command inside back quotes. If it's a builtin command, we 635 * want to save its output in a block obtained from malloc. Otherwise 636 * we fork off a subprocess and get the output of the command via a pipe. 637 * Should be called with interrupts off. 638 */ 639 640 void 641 evalbackcmd(union node *n, struct backcmd *result) 642 { 643 int pip[2]; 644 struct job *jp; 645 struct stackmark smark; 646 struct jmploc jmploc; 647 struct jmploc *savehandler; 648 struct localvar *savelocalvars; 649 650 result->fd = -1; 651 result->buf = NULL; 652 result->nleft = 0; 653 result->jp = NULL; 654 if (n == NULL) { 655 exitstatus = 0; 656 return; 657 } 658 setstackmark(&smark); 659 exitstatus = oexitstatus; 660 if (is_valid_fast_cmdsubst(n)) { 661 savelocalvars = localvars; 662 localvars = NULL; 663 forcelocal++; 664 savehandler = handler; 665 if (setjmp(jmploc.loc)) { 666 if (exception == EXERROR || exception == EXEXEC) 667 exitstatus = 2; 668 else if (exception != 0) { 669 handler = savehandler; 670 forcelocal--; 671 poplocalvars(); 672 localvars = savelocalvars; 673 longjmp(handler->loc, 1); 674 } 675 } else { 676 handler = &jmploc; 677 evalcommand(n, EV_BACKCMD, result); 678 } 679 handler = savehandler; 680 forcelocal--; 681 poplocalvars(); 682 localvars = savelocalvars; 683 } else { 684 if (pipe(pip) < 0) 685 error("Pipe call failed: %s", strerror(errno)); 686 jp = makejob(n, 1); 687 if (forkshell(jp, n, FORK_NOJOB) == 0) { 688 FORCEINTON; 689 close(pip[0]); 690 if (pip[1] != 1) { 691 dup2(pip[1], 1); 692 close(pip[1]); 693 } 694 evaltree(n, EV_EXIT); 695 } 696 close(pip[1]); 697 result->fd = pip[0]; 698 result->jp = jp; 699 } 700 popstackmark(&smark); 701 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 702 result->fd, result->buf, result->nleft, result->jp)); 703 } 704 705 static int 706 mustexpandto(const char *argtext, const char *mask) 707 { 708 for (;;) { 709 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) { 710 argtext++; 711 continue; 712 } 713 if (*argtext == CTLESC) 714 argtext++; 715 else if (BASESYNTAX[(int)*argtext] == CCTL) 716 return (0); 717 if (*argtext != *mask) 718 return (0); 719 if (*argtext == '\0') 720 return (1); 721 argtext++; 722 mask++; 723 } 724 } 725 726 static int 727 isdeclarationcmd(struct narg *arg) 728 { 729 int have_command = 0; 730 731 if (arg == NULL) 732 return (0); 733 while (mustexpandto(arg->text, "command")) { 734 have_command = 1; 735 arg = &arg->next->narg; 736 if (arg == NULL) 737 return (0); 738 /* 739 * To also allow "command -p" and "command --" as part of 740 * a declaration command, add code here. 741 * We do not do this, as ksh does not do it either and it 742 * is not required by POSIX. 743 */ 744 } 745 return (mustexpandto(arg->text, "export") || 746 mustexpandto(arg->text, "readonly") || 747 (mustexpandto(arg->text, "local") && 748 (have_command || !isfunc("local")))); 749 } 750 751 static void 752 xtracecommand(struct arglist *varlist, struct arglist *arglist) 753 { 754 struct strlist *sp; 755 char sep = 0; 756 const char *p, *ps4; 757 758 ps4 = expandstr(ps4val()); 759 out2str(ps4 != NULL ? ps4 : ps4val()); 760 for (sp = varlist->list ; sp ; sp = sp->next) { 761 if (sep != 0) 762 out2c(' '); 763 p = strchr(sp->text, '='); 764 if (p != NULL) { 765 p++; 766 outbin(sp->text, p - sp->text, out2); 767 out2qstr(p); 768 } else 769 out2qstr(sp->text); 770 sep = ' '; 771 } 772 for (sp = arglist->list ; sp ; sp = sp->next) { 773 if (sep != 0) 774 out2c(' '); 775 /* Disambiguate command looking like assignment. */ 776 if (sp == arglist->list && 777 strchr(sp->text, '=') != NULL && 778 strchr(sp->text, '\'') == NULL) { 779 out2c('\''); 780 out2str(sp->text); 781 out2c('\''); 782 } else 783 out2qstr(sp->text); 784 sep = ' '; 785 } 786 out2c('\n'); 787 flushout(&errout); 788 } 789 790 /* 791 * Check if a builtin can safely be executed in the same process, 792 * even though it should be in a subshell (command substitution). 793 * Note that jobid, jobs, times and trap can show information not 794 * available in a child process; this is deliberate. 795 * The arguments should already have been expanded. 796 */ 797 static int 798 safe_builtin(int idx, int argc, char **argv) 799 { 800 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 801 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 802 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 803 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 804 idx == TYPECMD) 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 struct strlist *sp; 832 int mode; 833 int pip[2]; 834 struct cmdentry cmdentry; 835 struct job *jp; 836 struct jmploc jmploc; 837 struct jmploc *savehandler; 838 char *savecmdname; 839 struct shparam saveparam; 840 struct localvar *savelocalvars; 841 struct parsefile *savetopfile; 842 volatile int e; 843 char *lastarg; 844 int realstatus; 845 int do_clearcmdentry; 846 const char *path = pathval(); 847 848 /* First expand the arguments. */ 849 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 850 arglist.lastp = &arglist.list; 851 varlist.lastp = &varlist.list; 852 varflag = 1; 853 jp = NULL; 854 do_clearcmdentry = 0; 855 oexitstatus = exitstatus; 856 exitstatus = 0; 857 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 858 if (varflag && isassignment(argp->narg.text)) { 859 expandarg(argp, varflag == 1 ? &varlist : &arglist, 860 EXP_VARTILDE); 861 continue; 862 } else if (varflag == 1) 863 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0; 864 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 865 } 866 *arglist.lastp = NULL; 867 *varlist.lastp = NULL; 868 expredir(cmd->ncmd.redirect); 869 argc = 0; 870 for (sp = arglist.list ; sp ; sp = sp->next) 871 argc++; 872 /* Add one slot at the beginning for tryexec(). */ 873 argv = stalloc(sizeof (char *) * (argc + 2)); 874 argv++; 875 876 for (sp = arglist.list ; sp ; sp = sp->next) { 877 TRACE(("evalcommand arg: %s\n", sp->text)); 878 *argv++ = sp->text; 879 } 880 *argv = NULL; 881 lastarg = NULL; 882 if (iflag && funcnest == 0 && argc > 0) 883 lastarg = argv[-1]; 884 argv -= argc; 885 886 /* Print the command if xflag is set. */ 887 if (xflag) 888 xtracecommand(&varlist, &arglist); 889 890 /* Now locate the command. */ 891 if (argc == 0) { 892 /* Variable assignment(s) without command */ 893 cmdentry.cmdtype = CMDBUILTIN; 894 cmdentry.u.index = BLTINCMD; 895 cmdentry.special = 0; 896 } else { 897 static const char PATH[] = "PATH="; 898 int cmd_flags = 0, bltinonly = 0; 899 900 /* 901 * Modify the command lookup path, if a PATH= assignment 902 * is present 903 */ 904 for (sp = varlist.list ; sp ; sp = sp->next) 905 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 906 path = sp->text + sizeof(PATH) - 1; 907 /* 908 * On `PATH=... command`, we need to make 909 * sure that the command isn't using the 910 * non-updated hash table of the outer PATH 911 * setting and we need to make sure that 912 * the hash table isn't filled with items 913 * from the temporary setting. 914 * 915 * It would be better to forbit using and 916 * updating the table while this command 917 * runs, by the command finding mechanism 918 * is heavily integrated with hash handling, 919 * so we just delete the hash before and after 920 * the command runs. Partly deleting like 921 * changepatch() does doesn't seem worth the 922 * bookinging effort, since most such runs add 923 * directories in front of the new PATH. 924 */ 925 clearcmdentry(); 926 do_clearcmdentry = 1; 927 } 928 929 for (;;) { 930 if (bltinonly) { 931 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 932 if (cmdentry.u.index < 0) { 933 cmdentry.u.index = BLTINCMD; 934 argv--; 935 argc++; 936 break; 937 } 938 } else 939 find_command(argv[0], &cmdentry, cmd_flags, path); 940 /* implement the bltin and command builtins here */ 941 if (cmdentry.cmdtype != CMDBUILTIN) 942 break; 943 if (cmdentry.u.index == BLTINCMD) { 944 if (argc == 1) 945 break; 946 argv++; 947 argc--; 948 bltinonly = 1; 949 } else if (cmdentry.u.index == COMMANDCMD) { 950 if (argc == 1) 951 break; 952 if (!strcmp(argv[1], "-p")) { 953 if (argc == 2) 954 break; 955 if (argv[2][0] == '-') { 956 if (strcmp(argv[2], "--")) 957 break; 958 if (argc == 3) 959 break; 960 argv += 3; 961 argc -= 3; 962 } else { 963 argv += 2; 964 argc -= 2; 965 } 966 path = _PATH_STDPATH; 967 clearcmdentry(); 968 do_clearcmdentry = 1; 969 } else if (!strcmp(argv[1], "--")) { 970 if (argc == 2) 971 break; 972 argv += 2; 973 argc -= 2; 974 } else if (argv[1][0] == '-') 975 break; 976 else { 977 argv++; 978 argc--; 979 } 980 cmd_flags |= DO_NOFUNC; 981 bltinonly = 0; 982 } else 983 break; 984 } 985 /* 986 * Special builtins lose their special properties when 987 * called via 'command'. 988 */ 989 if (cmd_flags & DO_NOFUNC) 990 cmdentry.special = 0; 991 } 992 993 /* Fork off a child process if necessary. */ 994 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 995 && ((flags & EV_EXIT) == 0 || have_traps())) 996 || ((flags & EV_BACKCMD) != 0 997 && (cmdentry.cmdtype != CMDBUILTIN || 998 !safe_builtin(cmdentry.u.index, argc, argv)))) { 999 jp = makejob(cmd, 1); 1000 mode = FORK_FG; 1001 if (flags & EV_BACKCMD) { 1002 mode = FORK_NOJOB; 1003 if (pipe(pip) < 0) 1004 error("Pipe call failed: %s", strerror(errno)); 1005 } 1006 if (cmdentry.cmdtype == CMDNORMAL && 1007 cmd->ncmd.redirect == NULL && 1008 varlist.list == NULL && 1009 (mode == FORK_FG || mode == FORK_NOJOB) && 1010 !disvforkset() && !iflag && !mflag) { 1011 vforkexecshell(jp, argv, environment(), path, 1012 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL); 1013 goto parent; 1014 } 1015 if (forkshell(jp, cmd, mode) != 0) 1016 goto parent; /* at end of routine */ 1017 if (flags & EV_BACKCMD) { 1018 FORCEINTON; 1019 close(pip[0]); 1020 if (pip[1] != 1) { 1021 dup2(pip[1], 1); 1022 close(pip[1]); 1023 } 1024 flags &= ~EV_BACKCMD; 1025 } 1026 flags |= EV_EXIT; 1027 } 1028 1029 /* This is the child process if a fork occurred. */ 1030 /* Execute the command. */ 1031 if (cmdentry.cmdtype == CMDFUNCTION) { 1032 #ifdef DEBUG 1033 trputs("Shell function: "); trargs(argv); 1034 #endif 1035 saveparam = shellparam; 1036 shellparam.malloc = 0; 1037 shellparam.reset = 1; 1038 shellparam.nparam = argc - 1; 1039 shellparam.p = argv + 1; 1040 shellparam.optnext = NULL; 1041 INTOFF; 1042 savelocalvars = localvars; 1043 localvars = NULL; 1044 reffunc(cmdentry.u.func); 1045 savehandler = handler; 1046 if (setjmp(jmploc.loc)) { 1047 freeparam(&shellparam); 1048 shellparam = saveparam; 1049 popredir(); 1050 unreffunc(cmdentry.u.func); 1051 poplocalvars(); 1052 localvars = savelocalvars; 1053 funcnest--; 1054 handler = savehandler; 1055 longjmp(handler->loc, 1); 1056 } 1057 handler = &jmploc; 1058 funcnest++; 1059 redirect(cmd->ncmd.redirect, REDIR_PUSH); 1060 INTON; 1061 for (sp = varlist.list ; sp ; sp = sp->next) 1062 mklocal(sp->text); 1063 exitstatus = oexitstatus; 1064 evaltree(getfuncnode(cmdentry.u.func), 1065 flags & (EV_TESTED | EV_EXIT)); 1066 INTOFF; 1067 unreffunc(cmdentry.u.func); 1068 poplocalvars(); 1069 localvars = savelocalvars; 1070 freeparam(&shellparam); 1071 shellparam = saveparam; 1072 handler = savehandler; 1073 funcnest--; 1074 popredir(); 1075 INTON; 1076 if (evalskip == SKIPRETURN) { 1077 evalskip = 0; 1078 skipcount = 0; 1079 } 1080 if (jp) 1081 exitshell(exitstatus); 1082 } else if (cmdentry.cmdtype == CMDBUILTIN) { 1083 #ifdef DEBUG 1084 trputs("builtin command: "); trargs(argv); 1085 #endif 1086 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 1087 if (flags == EV_BACKCMD) { 1088 memout.nleft = 0; 1089 memout.nextc = memout.buf; 1090 memout.bufsize = 64; 1091 mode |= REDIR_BACKQ; 1092 } 1093 savecmdname = commandname; 1094 savetopfile = getcurrentfile(); 1095 cmdenviron = varlist.list; 1096 e = -1; 1097 savehandler = handler; 1098 if (setjmp(jmploc.loc)) { 1099 e = exception; 1100 if (e == EXINT) 1101 exitstatus = SIGINT+128; 1102 else if (e != EXEXIT) 1103 exitstatus = 2; 1104 goto cmddone; 1105 } 1106 handler = &jmploc; 1107 redirect(cmd->ncmd.redirect, mode); 1108 outclearerror(out1); 1109 /* 1110 * If there is no command word, redirection errors should 1111 * not be fatal but assignment errors should. 1112 */ 1113 if (argc == 0) 1114 cmdentry.special = 1; 1115 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1116 if (argc > 0) 1117 bltinsetlocale(); 1118 commandname = argv[0]; 1119 argptr = argv + 1; 1120 nextopt_optptr = NULL; /* initialize nextopt */ 1121 builtin_flags = flags; 1122 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1123 flushall(); 1124 if (outiserror(out1)) { 1125 warning("write error on stdout"); 1126 if (exitstatus == 0 || exitstatus == 1) 1127 exitstatus = 2; 1128 } 1129 cmddone: 1130 if (argc > 0) 1131 bltinunsetlocale(); 1132 cmdenviron = NULL; 1133 out1 = &output; 1134 out2 = &errout; 1135 freestdout(); 1136 handler = savehandler; 1137 commandname = savecmdname; 1138 if (jp) 1139 exitshell(exitstatus); 1140 if (flags == EV_BACKCMD) { 1141 backcmd->buf = memout.buf; 1142 backcmd->nleft = memout.nextc - memout.buf; 1143 memout.buf = NULL; 1144 } 1145 if (cmdentry.u.index != EXECCMD) 1146 popredir(); 1147 if (e != -1) { 1148 if ((e != EXERROR && e != EXEXEC) 1149 || cmdentry.special) 1150 exraise(e); 1151 popfilesupto(savetopfile); 1152 if (flags != EV_BACKCMD) 1153 FORCEINTON; 1154 } 1155 } else { 1156 #ifdef DEBUG 1157 trputs("normal command: "); trargs(argv); 1158 #endif 1159 redirect(cmd->ncmd.redirect, 0); 1160 for (sp = varlist.list ; sp ; sp = sp->next) 1161 setvareq(sp->text, VEXPORT|VSTACK); 1162 envp = environment(); 1163 shellexec(argv, envp, path, cmdentry.u.index); 1164 /*NOTREACHED*/ 1165 } 1166 goto out; 1167 1168 parent: /* parent process gets here (if we forked) */ 1169 if (mode == FORK_FG) { /* argument to fork */ 1170 INTOFF; 1171 exitstatus = waitforjob(jp, &realstatus); 1172 INTON; 1173 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1174 evalskip = SKIPBREAK; 1175 skipcount = loopnest; 1176 } 1177 } else if (mode == FORK_NOJOB) { 1178 backcmd->fd = pip[0]; 1179 close(pip[1]); 1180 backcmd->jp = jp; 1181 } 1182 1183 out: 1184 if (lastarg) 1185 setvar("_", lastarg, 0); 1186 if (do_clearcmdentry) 1187 clearcmdentry(); 1188 } 1189 1190 1191 1192 /* 1193 * Search for a command. This is called before we fork so that the 1194 * location of the command will be available in the parent as well as 1195 * the child. The check for "goodname" is an overly conservative 1196 * check that the name will not be subject to expansion. 1197 */ 1198 1199 static void 1200 prehash(union node *n) 1201 { 1202 struct cmdentry entry; 1203 1204 if (n && n->type == NCMD && n->ncmd.args) 1205 if (goodname(n->ncmd.args->narg.text)) 1206 find_command(n->ncmd.args->narg.text, &entry, 0, 1207 pathval()); 1208 } 1209 1210 1211 1212 /* 1213 * Builtin commands. Builtin commands whose functions are closely 1214 * tied to evaluation are implemented here. 1215 */ 1216 1217 /* 1218 * No command given, a bltin command with no arguments, or a bltin command 1219 * with an invalid name. 1220 */ 1221 1222 int 1223 bltincmd(int argc, char **argv) 1224 { 1225 if (argc > 1) { 1226 out2fmt_flush("%s: not found\n", argv[1]); 1227 return 127; 1228 } 1229 /* 1230 * Preserve exitstatus of a previous possible redirection 1231 * as POSIX mandates 1232 */ 1233 return exitstatus; 1234 } 1235 1236 1237 /* 1238 * Handle break and continue commands. Break, continue, and return are 1239 * all handled by setting the evalskip flag. The evaluation routines 1240 * above all check this flag, and if it is set they start skipping 1241 * commands rather than executing them. The variable skipcount is 1242 * the number of loops to break/continue, or the number of function 1243 * levels to return. (The latter is always 1.) It should probably 1244 * be an error to break out of more loops than exist, but it isn't 1245 * in the standard shell so we don't make it one here. 1246 */ 1247 1248 int 1249 breakcmd(int argc, char **argv) 1250 { 1251 long n; 1252 char *end; 1253 1254 if (argc > 1) { 1255 /* Allow arbitrarily large numbers. */ 1256 n = strtol(argv[1], &end, 10); 1257 if (!is_digit(argv[1][0]) || *end != '\0') 1258 error("Illegal number: %s", argv[1]); 1259 } else 1260 n = 1; 1261 if (n > loopnest) 1262 n = loopnest; 1263 if (n > 0) { 1264 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1265 skipcount = n; 1266 } 1267 return 0; 1268 } 1269 1270 /* 1271 * The `command' command. 1272 */ 1273 int 1274 commandcmd(int argc __unused, char **argv __unused) 1275 { 1276 const char *path; 1277 int ch; 1278 int cmd = -1; 1279 1280 path = bltinlookup("PATH", 1); 1281 1282 while ((ch = nextopt("pvV")) != '\0') { 1283 switch (ch) { 1284 case 'p': 1285 path = _PATH_STDPATH; 1286 break; 1287 case 'v': 1288 cmd = TYPECMD_SMALLV; 1289 break; 1290 case 'V': 1291 cmd = TYPECMD_BIGV; 1292 break; 1293 } 1294 } 1295 1296 if (cmd != -1) { 1297 if (*argptr == NULL || argptr[1] != NULL) 1298 error("wrong number of arguments"); 1299 return typecmd_impl(2, argptr - 1, cmd, path); 1300 } 1301 if (*argptr != NULL) 1302 error("commandcmd bad call"); 1303 1304 /* 1305 * Do nothing successfully if no command was specified; 1306 * ksh also does this. 1307 */ 1308 return 0; 1309 } 1310 1311 1312 /* 1313 * The return command. 1314 */ 1315 1316 int 1317 returncmd(int argc, char **argv) 1318 { 1319 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1320 1321 evalskip = SKIPRETURN; 1322 skipcount = 1; 1323 return ret; 1324 } 1325 1326 1327 int 1328 falsecmd(int argc __unused, char **argv __unused) 1329 { 1330 return 1; 1331 } 1332 1333 1334 int 1335 truecmd(int argc __unused, char **argv __unused) 1336 { 1337 return 0; 1338 } 1339 1340 1341 int 1342 execcmd(int argc, char **argv) 1343 { 1344 /* 1345 * Because we have historically not supported any options, 1346 * only treat "--" specially. 1347 */ 1348 if (argc > 1 && strcmp(argv[1], "--") == 0) 1349 argc--, argv++; 1350 if (argc > 1) { 1351 struct strlist *sp; 1352 1353 iflag = 0; /* exit on error */ 1354 mflag = 0; 1355 optschanged(); 1356 for (sp = cmdenviron; sp ; sp = sp->next) 1357 setvareq(sp->text, VEXPORT|VSTACK); 1358 shellexec(argv + 1, environment(), pathval(), 0); 1359 1360 } 1361 return 0; 1362 } 1363 1364 1365 int 1366 timescmd(int argc __unused, char **argv __unused) 1367 { 1368 struct rusage ru; 1369 long shumins, shsmins, chumins, chsmins; 1370 double shusecs, shssecs, chusecs, chssecs; 1371 1372 if (getrusage(RUSAGE_SELF, &ru) < 0) 1373 return 1; 1374 shumins = ru.ru_utime.tv_sec / 60; 1375 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1376 shsmins = ru.ru_stime.tv_sec / 60; 1377 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1378 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1379 return 1; 1380 chumins = ru.ru_utime.tv_sec / 60; 1381 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1382 chsmins = ru.ru_stime.tv_sec / 60; 1383 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1384 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1385 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1386 return 0; 1387 } 1388