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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)eval.c 8.9 (Berkeley) 6/8/95 37 * $FreeBSD: head/bin/sh/eval.c 247206 2013-02-23 22:50:57Z jilles $ 38 */ 39 40 #include <sys/time.h> 41 #include <sys/resource.h> 42 #include <sys/wait.h> /* For WIFSIGNALED(status) */ 43 44 #include <errno.h> 45 #include <paths.h> 46 #include <signal.h> 47 #include <stdlib.h> 48 #include <unistd.h> 49 50 /* 51 * Evaluate a command. 52 */ 53 54 #include "shell.h" 55 #include "nodes.h" 56 #include "syntax.h" 57 #include "expand.h" 58 #include "parser.h" 59 #include "jobs.h" 60 #include "eval.h" 61 #include "builtins.h" 62 #include "options.h" 63 #include "exec.h" 64 #include "redir.h" 65 #include "input.h" 66 #include "output.h" 67 #include "trap.h" 68 #include "var.h" 69 #include "memalloc.h" 70 #include "error.h" 71 #include "show.h" 72 #include "mystring.h" 73 #ifndef NO_HISTORY 74 #include "myhistedit.h" 75 #endif 76 77 78 int evalskip; /* set if we are skipping commands */ 79 int skipcount; /* number of levels to skip */ 80 MKINIT int loopnest; /* current loop nesting level */ 81 int funcnest; /* depth of function calls */ 82 static int builtin_flags; /* evalcommand flags for builtins */ 83 84 85 const char *commandname; 86 struct strlist *cmdenviron; 87 int exitstatus; /* exit status of last command */ 88 int oexitstatus; /* saved exit status */ 89 90 91 static void evalloop(union node *, int); 92 static void evalfor(union node *, int); 93 static union node *evalcase(union node *); 94 static void evalsubshell(union node *, int); 95 static void evalredir(union node *, int); 96 static void exphere(union node *, struct arglist *); 97 static void expredir(union node *); 98 static void evalpipe(union node *); 99 static int is_valid_fast_cmdsubst(union node *n); 100 static void evalcommand(union node *, int, struct backcmd *); 101 static void prehash(union node *); 102 103 104 /* 105 * Called to reset things after an exception. 106 */ 107 108 #ifdef mkinit 109 INCLUDE "eval.h" 110 111 RESET { 112 evalskip = 0; 113 loopnest = 0; 114 funcnest = 0; 115 } 116 #endif 117 118 119 120 /* 121 * The eval command. 122 */ 123 124 int 125 evalcmd(int argc, char **argv) 126 { 127 char *p; 128 char *concat; 129 char **ap; 130 131 if (argc > 1) { 132 p = argv[1]; 133 if (argc > 2) { 134 STARTSTACKSTR(concat); 135 ap = argv + 2; 136 for (;;) { 137 STPUTS(p, concat); 138 if ((p = *ap++) == NULL) 139 break; 140 STPUTC(' ', concat); 141 } 142 STPUTC('\0', concat); 143 p = grabstackstr(concat); 144 } 145 evalstring(p, builtin_flags); 146 } else 147 exitstatus = 0; 148 return exitstatus; 149 } 150 151 152 /* 153 * Execute a command or commands contained in a string. 154 */ 155 156 void 157 evalstring(char *s, int flags) 158 { 159 union node *n; 160 struct stackmark smark; 161 int flags_exit; 162 int any; 163 164 flags_exit = flags & EV_EXIT; 165 flags &= ~EV_EXIT; 166 any = 0; 167 setstackmark(&smark); 168 setinputstring(s, 1); 169 while ((n = parsecmd(0)) != NEOF) { 170 if (n != NULL && !nflag) { 171 if (flags_exit && preadateof()) 172 evaltree(n, flags | EV_EXIT); 173 else 174 evaltree(n, flags); 175 any = 1; 176 } 177 popstackmark(&smark); 178 setstackmark(&smark); 179 } 180 popfile(); 181 popstackmark(&smark); 182 if (!any) 183 exitstatus = 0; 184 if (flags_exit) 185 exraise(EXEXIT); 186 } 187 188 189 /* 190 * Evaluate a parse tree. The value is left in the global variable 191 * exitstatus. 192 */ 193 194 void 195 evaltree(union node *n, int flags) 196 { 197 int do_etest; 198 union node *next; 199 struct stackmark smark; 200 201 setstackmark(&smark); 202 do_etest = 0; 203 if (n == NULL) { 204 TRACE(("evaltree(NULL) called\n")); 205 exitstatus = 0; 206 goto out; 207 } 208 do { 209 next = NULL; 210 #ifndef NO_HISTORY 211 displayhist = 1; /* show history substitutions done with fc */ 212 #endif 213 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 214 switch (n->type) { 215 case NSEMI: 216 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 217 if (evalskip) 218 goto out; 219 next = n->nbinary.ch2; 220 break; 221 case NAND: 222 evaltree(n->nbinary.ch1, EV_TESTED); 223 if (evalskip || exitstatus != 0) { 224 goto out; 225 } 226 next = n->nbinary.ch2; 227 break; 228 case NOR: 229 evaltree(n->nbinary.ch1, EV_TESTED); 230 if (evalskip || exitstatus == 0) 231 goto out; 232 next = n->nbinary.ch2; 233 break; 234 case NREDIR: 235 evalredir(n, flags); 236 break; 237 case NSUBSHELL: 238 evalsubshell(n, flags); 239 do_etest = !(flags & EV_TESTED); 240 break; 241 case NBACKGND: 242 evalsubshell(n, flags); 243 break; 244 case NIF: { 245 evaltree(n->nif.test, EV_TESTED); 246 if (evalskip) 247 goto out; 248 if (exitstatus == 0) 249 next = n->nif.ifpart; 250 else if (n->nif.elsepart) 251 next = n->nif.elsepart; 252 else 253 exitstatus = 0; 254 break; 255 } 256 case NWHILE: 257 case NUNTIL: 258 evalloop(n, flags & ~EV_EXIT); 259 break; 260 case NFOR: 261 evalfor(n, flags & ~EV_EXIT); 262 break; 263 case NCASE: 264 next = evalcase(n); 265 break; 266 case NCLIST: 267 next = n->nclist.body; 268 break; 269 case NCLISTFALLTHRU: 270 if (n->nclist.body) { 271 evaltree(n->nclist.body, flags & ~EV_EXIT); 272 if (evalskip) 273 goto out; 274 } 275 next = n->nclist.next; 276 break; 277 case NDEFUN: 278 defun(n->narg.text, n->narg.next); 279 exitstatus = 0; 280 break; 281 case NNOT: 282 evaltree(n->nnot.com, EV_TESTED); 283 exitstatus = !exitstatus; 284 break; 285 286 case NPIPE: 287 evalpipe(n); 288 do_etest = !(flags & EV_TESTED); 289 break; 290 case NCMD: 291 evalcommand(n, flags, NULL); 292 do_etest = !(flags & EV_TESTED); 293 break; 294 default: 295 out1fmt("Node type = %d\n", n->type); 296 flushout(&output); 297 break; 298 } 299 n = next; 300 popstackmark(&smark); 301 setstackmark(&smark); 302 } while (n != NULL); 303 out: 304 popstackmark(&smark); 305 if (pendingsig) 306 dotrap(); 307 if (eflag && exitstatus != 0 && do_etest) 308 exitshell(exitstatus); 309 if (flags & EV_EXIT) 310 exraise(EXEXIT); 311 } 312 313 314 static void 315 evalloop(union node *n, int flags) 316 { 317 int status; 318 319 loopnest++; 320 status = 0; 321 for (;;) { 322 evaltree(n->nbinary.ch1, EV_TESTED); 323 if (evalskip) { 324 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 325 evalskip = 0; 326 continue; 327 } 328 if (evalskip == SKIPBREAK && --skipcount <= 0) 329 evalskip = 0; 330 if (evalskip == SKIPFUNC || evalskip == SKIPFILE) 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 if (evalskip) 344 goto skipping; 345 } 346 loopnest--; 347 exitstatus = status; 348 } 349 350 351 352 static void 353 evalfor(union node *n, int flags) 354 { 355 struct arglist arglist; 356 union node *argp; 357 struct strlist *sp; 358 int status; 359 360 arglist.lastp = &arglist.list; 361 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 362 oexitstatus = exitstatus; 363 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 364 } 365 *arglist.lastp = NULL; 366 367 loopnest++; 368 status = 0; 369 for (sp = arglist.list ; sp ; sp = sp->next) { 370 setvar(n->nfor.var, sp->text, 0); 371 evaltree(n->nfor.body, flags); 372 status = exitstatus; 373 if (evalskip) { 374 if (evalskip == SKIPCONT && --skipcount <= 0) { 375 evalskip = 0; 376 continue; 377 } 378 if (evalskip == SKIPBREAK && --skipcount <= 0) 379 evalskip = 0; 380 break; 381 } 382 } 383 loopnest--; 384 exitstatus = status; 385 } 386 387 388 /* 389 * Evaluate a case statement, returning the selected tree. 390 * 391 * The exit status needs care to get right. 392 */ 393 394 static union node * 395 evalcase(union node *n) 396 { 397 union node *cp; 398 union node *patp; 399 struct arglist arglist; 400 401 arglist.lastp = &arglist.list; 402 oexitstatus = exitstatus; 403 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 404 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) { 405 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 406 if (casematch(patp, arglist.list->text)) { 407 while (cp->nclist.next && 408 cp->type == NCLISTFALLTHRU && 409 cp->nclist.body == NULL) 410 cp = cp->nclist.next; 411 if (cp->nclist.next && 412 cp->type == NCLISTFALLTHRU) 413 return (cp); 414 if (cp->nclist.body == NULL) 415 exitstatus = 0; 416 return (cp->nclist.body); 417 } 418 } 419 } 420 exitstatus = 0; 421 return (NULL); 422 } 423 424 425 426 /* 427 * Kick off a subshell to evaluate a tree. 428 */ 429 430 static void 431 evalsubshell(union node *n, int flags) 432 { 433 struct job *jp; 434 int backgnd = (n->type == NBACKGND); 435 436 oexitstatus = exitstatus; 437 expredir(n->nredir.redirect); 438 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 439 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 440 if (backgnd) 441 flags &=~ EV_TESTED; 442 redirect(n->nredir.redirect, 0); 443 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 444 } else if (!backgnd) { 445 INTOFF; 446 exitstatus = waitforjob(jp, NULL); 447 INTON; 448 } else 449 exitstatus = 0; 450 } 451 452 453 /* 454 * Evaluate a redirected compound command. 455 */ 456 457 static void 458 evalredir(union node *n, int flags) 459 { 460 struct jmploc jmploc; 461 struct jmploc *savehandler; 462 volatile int in_redirect = 1; 463 464 oexitstatus = exitstatus; 465 expredir(n->nredir.redirect); 466 savehandler = handler; 467 if (setjmp(jmploc.loc)) { 468 int e; 469 470 handler = savehandler; 471 e = exception; 472 popredir(); 473 if (e == EXERROR || e == EXEXEC) { 474 if (in_redirect) { 475 exitstatus = 2; 476 return; 477 } 478 } 479 longjmp(handler->loc, 1); 480 } else { 481 INTOFF; 482 handler = &jmploc; 483 redirect(n->nredir.redirect, REDIR_PUSH); 484 in_redirect = 0; 485 INTON; 486 evaltree(n->nredir.n, flags); 487 } 488 INTOFF; 489 handler = savehandler; 490 popredir(); 491 INTON; 492 } 493 494 495 static void 496 exphere(union node *redir, struct arglist *fn) 497 { 498 struct jmploc jmploc; 499 struct jmploc *savehandler; 500 struct localvar *savelocalvars; 501 int need_longjmp = 0; 502 503 redir->nhere.expdoc = nullstr; 504 savelocalvars = localvars; 505 localvars = NULL; 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->list->text; 514 INTOFF; 515 } 516 handler = savehandler; 517 forcelocal--; 518 poplocalvars(); 519 localvars = savelocalvars; 520 if (need_longjmp) 521 longjmp(handler->loc, 1); 522 INTON; 523 } 524 525 526 /* 527 * Compute the names of the files in a redirection list. 528 */ 529 530 static void 531 expredir(union node *n) 532 { 533 union node *redir; 534 535 for (redir = n ; redir ; redir = redir->nfile.next) { 536 struct arglist fn; 537 fn.lastp = &fn.list; 538 switch (redir->type) { 539 case NFROM: 540 case NTO: 541 case NFROMTO: 542 case NAPPEND: 543 case NCLOBBER: 544 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 545 redir->nfile.expfname = fn.list->text; 546 break; 547 case NFROMFD: 548 case NTOFD: 549 if (redir->ndup.vname) { 550 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 551 fixredir(redir, fn.list->text, 1); 552 } 553 break; 554 case NXHERE: 555 exphere(redir, &fn); 556 break; 557 } 558 } 559 } 560 561 562 563 /* 564 * Evaluate a pipeline. All the processes in the pipeline are children 565 * of the process creating the pipeline. (This differs from some versions 566 * of the shell, which make the last process in a pipeline the parent 567 * of all the rest.) 568 */ 569 570 static void 571 evalpipe(union node *n) 572 { 573 struct job *jp; 574 struct nodelist *lp; 575 int pipelen; 576 int prevfd; 577 int pip[2]; 578 579 TRACE(("evalpipe(%p) called\n", (void *)n)); 580 pipelen = 0; 581 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 582 pipelen++; 583 INTOFF; 584 jp = makejob(n, pipelen); 585 prevfd = -1; 586 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 587 prehash(lp->n); 588 pip[1] = -1; 589 if (lp->next) { 590 if (pipe(pip) < 0) { 591 if (prevfd >= 0) 592 close(prevfd); 593 error("Pipe call failed: %s", strerror(errno)); 594 } 595 } 596 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 597 INTON; 598 if (prevfd > 0) { 599 dup2(prevfd, 0); 600 close(prevfd); 601 } 602 if (pip[1] >= 0) { 603 if (!(prevfd >= 0 && pip[0] == 0)) 604 close(pip[0]); 605 if (pip[1] != 1) { 606 dup2(pip[1], 1); 607 close(pip[1]); 608 } 609 } 610 evaltree(lp->n, EV_EXIT); 611 } 612 if (prevfd >= 0) 613 close(prevfd); 614 prevfd = pip[0]; 615 if (pip[1] != -1) 616 close(pip[1]); 617 } 618 INTON; 619 if (n->npipe.backgnd == 0) { 620 INTOFF; 621 exitstatus = waitforjob(jp, NULL); 622 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 623 INTON; 624 } else 625 exitstatus = 0; 626 } 627 628 629 630 static int 631 is_valid_fast_cmdsubst(union node *n) 632 { 633 634 return (n->type == NCMD); 635 } 636 637 /* 638 * Execute a command inside back quotes. If it's a builtin command, we 639 * want to save its output in a block obtained from malloc. Otherwise 640 * we fork off a subprocess and get the output of the command via a pipe. 641 * Should be called with interrupts off. 642 */ 643 644 void 645 evalbackcmd(union node *n, struct backcmd *result) 646 { 647 int pip[2]; 648 struct job *jp; 649 struct stackmark smark; 650 struct jmploc jmploc; 651 struct jmploc *savehandler; 652 struct localvar *savelocalvars; 653 654 setstackmark(&smark); 655 result->fd = -1; 656 result->buf = NULL; 657 result->nleft = 0; 658 result->jp = NULL; 659 if (n == NULL) { 660 exitstatus = 0; 661 goto out; 662 } 663 exitstatus = oexitstatus; 664 if (is_valid_fast_cmdsubst(n)) { 665 savelocalvars = localvars; 666 localvars = NULL; 667 forcelocal++; 668 savehandler = handler; 669 if (setjmp(jmploc.loc)) { 670 if (exception == EXERROR || exception == EXEXEC) 671 exitstatus = 2; 672 else if (exception != 0) { 673 handler = savehandler; 674 forcelocal--; 675 poplocalvars(); 676 localvars = savelocalvars; 677 longjmp(handler->loc, 1); 678 } 679 } else { 680 handler = &jmploc; 681 evalcommand(n, EV_BACKCMD, result); 682 } 683 handler = savehandler; 684 forcelocal--; 685 poplocalvars(); 686 localvars = savelocalvars; 687 } else { 688 if (pipe(pip) < 0) 689 error("Pipe call failed: %s", strerror(errno)); 690 jp = makejob(n, 1); 691 if (forkshell(jp, n, FORK_NOJOB) == 0) { 692 FORCEINTON; 693 close(pip[0]); 694 if (pip[1] != 1) { 695 dup2(pip[1], 1); 696 close(pip[1]); 697 } 698 evaltree(n, EV_EXIT); 699 } 700 close(pip[1]); 701 result->fd = pip[0]; 702 result->jp = jp; 703 } 704 out: 705 popstackmark(&smark); 706 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 707 result->fd, result->buf, result->nleft, result->jp)); 708 } 709 710 static int 711 mustexpandto(const char *argtext, const char *mask) 712 { 713 for (;;) { 714 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) { 715 argtext++; 716 continue; 717 } 718 if (*argtext == CTLESC) 719 argtext++; 720 else if (BASESYNTAX[(int)*argtext] == CCTL) 721 return (0); 722 if (*argtext != *mask) 723 return (0); 724 if (*argtext == '\0') 725 return (1); 726 argtext++; 727 mask++; 728 } 729 } 730 731 static int 732 isdeclarationcmd(struct narg *arg) 733 { 734 int have_command = 0; 735 736 if (arg == NULL) 737 return (0); 738 while (mustexpandto(arg->text, "command")) { 739 have_command = 1; 740 arg = &arg->next->narg; 741 if (arg == NULL) 742 return (0); 743 /* 744 * To also allow "command -p" and "command --" as part of 745 * a declaration command, add code here. 746 * We do not do this, as ksh does not do it either and it 747 * is not required by POSIX. 748 */ 749 } 750 return (mustexpandto(arg->text, "export") || 751 mustexpandto(arg->text, "readonly") || 752 (mustexpandto(arg->text, "local") && 753 (have_command || !isfunc("local")))); 754 } 755 756 /* 757 * Check if a builtin can safely be executed in the same process, 758 * even though it should be in a subshell (command substitution). 759 * Note that jobid, jobs, times and trap can show information not 760 * available in a child process; this is deliberate. 761 * The arguments should already have been expanded. 762 */ 763 static int 764 safe_builtin(int idx, int argc, char **argv) 765 { 766 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 767 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 768 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 769 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 770 idx == TYPECMD) 771 return (1); 772 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 773 idx == UMASKCMD) 774 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 775 if (idx == SETCMD) 776 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 777 argv[1][0] == '+') && argv[1][1] == 'o' && 778 argv[1][2] == '\0')); 779 return (0); 780 } 781 782 /* 783 * Execute a simple command. 784 * Note: This may or may not return if (flags & EV_EXIT). 785 */ 786 787 static void 788 evalcommand(union node *cmd, int flgs, struct backcmd *backcmd) 789 { 790 union node *argp; 791 struct arglist arglist; 792 struct arglist varlist; 793 volatile int flags = flgs; 794 char **volatile argv; 795 volatile int argc; 796 char **envp; 797 int varflag; 798 struct strlist *sp; 799 int mode; 800 int pip[2]; 801 struct cmdentry cmdentry; 802 struct job *volatile jp; 803 struct jmploc jmploc; 804 struct jmploc *savehandler; 805 const char *savecmdname; 806 struct shparam saveparam; 807 struct localvar *savelocalvars; 808 struct parsefile *savetopfile; 809 volatile int e; 810 char *volatile lastarg; 811 int realstatus; 812 volatile int do_clearcmdentry; 813 const char *path = pathval(); 814 815 /* First expand the arguments. */ 816 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 817 arglist.lastp = &arglist.list; 818 varlist.lastp = &varlist.list; 819 varflag = 1; 820 jp = NULL; 821 do_clearcmdentry = 0; 822 oexitstatus = exitstatus; 823 exitstatus = 0; 824 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 825 if (varflag && isassignment(argp->narg.text)) { 826 expandarg(argp, varflag == 1 ? &varlist : &arglist, 827 EXP_VARTILDE); 828 continue; 829 } else if (varflag == 1) 830 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0; 831 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 832 } 833 *arglist.lastp = NULL; 834 *varlist.lastp = NULL; 835 expredir(cmd->ncmd.redirect); 836 argc = 0; 837 for (sp = arglist.list ; sp ; sp = sp->next) 838 argc++; 839 /* Add one slot at the beginning for tryexec(). */ 840 argv = stalloc(sizeof (char *) * (argc + 2)); 841 argv++; 842 843 for (sp = arglist.list ; sp ; sp = sp->next) { 844 TRACE(("evalcommand arg: %s\n", sp->text)); 845 *argv++ = sp->text; 846 } 847 *argv = NULL; 848 lastarg = NULL; 849 if (iflag && funcnest == 0 && argc > 0) 850 lastarg = argv[-1]; 851 argv -= argc; 852 853 /* Print the command if xflag is set. */ 854 if (xflag) { 855 char sep = 0; 856 const char *p, *ps4; 857 ps4 = expandstr(ps4val()); 858 out2str(ps4 != NULL ? ps4 : ps4val()); 859 for (sp = varlist.list ; sp ; sp = sp->next) { 860 if (sep != 0) 861 out2c(' '); 862 p = strchr(sp->text, '='); 863 if (p != NULL) { 864 p++; 865 outbin(sp->text, p - sp->text, out2); 866 out2qstr(p); 867 } else 868 out2qstr(sp->text); 869 sep = ' '; 870 } 871 for (sp = arglist.list ; sp ; sp = sp->next) { 872 if (sep != 0) 873 out2c(' '); 874 /* Disambiguate command looking like assignment. */ 875 if (sp == arglist.list && 876 strchr(sp->text, '=') != NULL && 877 strchr(sp->text, '\'') == NULL) { 878 out2c('\''); 879 out2str(sp->text); 880 out2c('\''); 881 } else 882 out2qstr(sp->text); 883 sep = ' '; 884 } 885 out2c('\n'); 886 flushout(&errout); 887 } 888 889 /* Now locate the command. */ 890 if (argc == 0) { 891 /* Variable assignment(s) without command */ 892 cmdentry.cmdtype = CMDBUILTIN; 893 cmdentry.u.index = BLTINCMD; 894 cmdentry.special = 0; 895 } else { 896 static const char PATH[] = "PATH="; 897 int cmd_flags = 0, bltinonly = 0; 898 899 /* 900 * Modify the command lookup path, if a PATH= assignment 901 * is present 902 */ 903 for (sp = varlist.list ; sp ; sp = sp->next) 904 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 905 path = sp->text + sizeof(PATH) - 1; 906 /* 907 * On `PATH=... command`, we need to make 908 * sure that the command isn't using the 909 * non-updated hash table of the outer PATH 910 * setting and we need to make sure that 911 * the hash table isn't filled with items 912 * from the temporary setting. 913 * 914 * It would be better to forbit using and 915 * updating the table while this command 916 * runs, by the command finding mechanism 917 * is heavily integrated with hash handling, 918 * so we just delete the hash before and after 919 * the command runs. Partly deleting like 920 * changepatch() does doesn't seem worth the 921 * bookinging effort, since most such runs add 922 * directories in front of the new PATH. 923 */ 924 clearcmdentry(); 925 do_clearcmdentry = 1; 926 } 927 928 for (;;) { 929 if (bltinonly) { 930 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 931 if (cmdentry.u.index < 0) { 932 cmdentry.u.index = BLTINCMD; 933 argv--; 934 argc++; 935 break; 936 } 937 } else 938 find_command(argv[0], &cmdentry, cmd_flags, path); 939 /* implement the bltin and command builtins here */ 940 if (cmdentry.cmdtype != CMDBUILTIN) 941 break; 942 if (cmdentry.u.index == BLTINCMD) { 943 if (argc == 1) 944 break; 945 argv++; 946 argc--; 947 bltinonly = 1; 948 } else if (cmdentry.u.index == COMMANDCMD) { 949 if (argc == 1) 950 break; 951 if (!strcmp(argv[1], "-p")) { 952 if (argc == 2) 953 break; 954 if (argv[2][0] == '-') { 955 if (strcmp(argv[2], "--")) 956 break; 957 if (argc == 3) 958 break; 959 argv += 3; 960 argc -= 3; 961 } else { 962 argv += 2; 963 argc -= 2; 964 } 965 path = _PATH_STDPATH; 966 clearcmdentry(); 967 do_clearcmdentry = 1; 968 } else if (!strcmp(argv[1], "--")) { 969 if (argc == 2) 970 break; 971 argv += 2; 972 argc -= 2; 973 } else if (argv[1][0] == '-') 974 break; 975 else { 976 argv++; 977 argc--; 978 } 979 cmd_flags |= DO_NOFUNC; 980 bltinonly = 0; 981 } else 982 break; 983 } 984 /* 985 * Special builtins lose their special properties when 986 * called via 'command'. 987 */ 988 if (cmd_flags & DO_NOFUNC) 989 cmdentry.special = 0; 990 } 991 992 /* Fork off a child process if necessary. */ 993 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 994 && ((flags & EV_EXIT) == 0 || have_traps())) 995 || ((flags & EV_BACKCMD) != 0 996 && (cmdentry.cmdtype != CMDBUILTIN || 997 !safe_builtin(cmdentry.u.index, argc, argv)))) { 998 jp = makejob(cmd, 1); 999 mode = FORK_FG; 1000 if (flags & EV_BACKCMD) { 1001 mode = FORK_NOJOB; 1002 if (pipe(pip) < 0) 1003 error("Pipe call failed: %s", strerror(errno)); 1004 } 1005 if (cmdentry.cmdtype == CMDNORMAL && 1006 cmd->ncmd.redirect == NULL && 1007 varlist.list == NULL && 1008 (mode == FORK_FG || mode == FORK_NOJOB) && 1009 !disvforkset() && !iflag && !mflag) { 1010 vforkexecshell(jp, argv, environment(), path, 1011 cmdentry.u.index, flags & EV_BACKCMD ? pip : NULL); 1012 goto parent; 1013 } 1014 if (forkshell(jp, cmd, mode) != 0) 1015 goto parent; /* at end of routine */ 1016 if (flags & EV_BACKCMD) { 1017 FORCEINTON; 1018 close(pip[0]); 1019 if (pip[1] != 1) { 1020 dup2(pip[1], 1); 1021 close(pip[1]); 1022 } 1023 flags &= ~EV_BACKCMD; 1024 } 1025 flags |= EV_EXIT; 1026 } 1027 1028 /* This is the child process if a fork occurred. */ 1029 /* Execute the command. */ 1030 if (cmdentry.cmdtype == CMDFUNCTION) { 1031 #ifdef DEBUG 1032 trputs("Shell function: "); trargs(argv); 1033 #endif 1034 saveparam = shellparam; 1035 shellparam.malloc = 0; 1036 shellparam.reset = 1; 1037 shellparam.nparam = argc - 1; 1038 shellparam.p = argv + 1; 1039 shellparam.optnext = NULL; 1040 INTOFF; 1041 savelocalvars = localvars; 1042 localvars = NULL; 1043 reffunc(cmdentry.u.func); 1044 savehandler = handler; 1045 if (setjmp(jmploc.loc)) { 1046 freeparam(&shellparam); 1047 shellparam = saveparam; 1048 popredir(); 1049 unreffunc(cmdentry.u.func); 1050 poplocalvars(); 1051 localvars = savelocalvars; 1052 funcnest--; 1053 handler = savehandler; 1054 longjmp(handler->loc, 1); 1055 } 1056 handler = &jmploc; 1057 funcnest++; 1058 redirect(cmd->ncmd.redirect, REDIR_PUSH); 1059 INTON; 1060 for (sp = varlist.list ; sp ; sp = sp->next) 1061 mklocal(sp->text); 1062 exitstatus = oexitstatus; 1063 evaltree(getfuncnode(cmdentry.u.func), 1064 flags & (EV_TESTED | EV_EXIT)); 1065 INTOFF; 1066 unreffunc(cmdentry.u.func); 1067 poplocalvars(); 1068 localvars = savelocalvars; 1069 freeparam(&shellparam); 1070 shellparam = saveparam; 1071 handler = savehandler; 1072 funcnest--; 1073 popredir(); 1074 INTON; 1075 if (evalskip == SKIPFUNC) { 1076 evalskip = 0; 1077 skipcount = 0; 1078 } 1079 if (jp) 1080 exitshell(exitstatus); 1081 } else if (cmdentry.cmdtype == CMDBUILTIN) { 1082 #ifdef DEBUG 1083 trputs("builtin command: "); trargs(argv); 1084 #endif 1085 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 1086 if (flags == EV_BACKCMD) { 1087 memout.nleft = 0; 1088 memout.nextc = memout.buf; 1089 memout.bufsize = 64; 1090 mode |= REDIR_BACKQ; 1091 } 1092 savecmdname = commandname; 1093 savetopfile = getcurrentfile(); 1094 cmdenviron = varlist.list; 1095 e = -1; 1096 savehandler = handler; 1097 if (setjmp(jmploc.loc)) { 1098 e = exception; 1099 if (e == EXINT) 1100 exitstatus = SIGINT+128; 1101 else if (e != EXEXIT) 1102 exitstatus = 2; 1103 goto cmddone; 1104 } 1105 handler = &jmploc; 1106 redirect(cmd->ncmd.redirect, mode); 1107 outclearerror(out1); 1108 /* 1109 * If there is no command word, redirection errors should 1110 * not be fatal but assignment errors should. 1111 */ 1112 if (argc == 0) 1113 cmdentry.special = 1; 1114 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1115 if (argc > 0) 1116 bltinsetlocale(); 1117 commandname = argv[0]; 1118 argptr = argv + 1; 1119 nextopt_optptr = NULL; /* initialize nextopt */ 1120 builtin_flags = flags; 1121 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1122 flushall(); 1123 if (outiserror(out1)) { 1124 warning("write error on stdout"); 1125 if (exitstatus == 0 || exitstatus == 1) 1126 exitstatus = 2; 1127 } 1128 cmddone: 1129 if (argc > 0) 1130 bltinunsetlocale(); 1131 cmdenviron = NULL; 1132 out1 = &output; 1133 out2 = &errout; 1134 freestdout(); 1135 handler = savehandler; 1136 commandname = savecmdname; 1137 if (jp) 1138 exitshell(exitstatus); 1139 if (flags == EV_BACKCMD) { 1140 backcmd->buf = memout.buf; 1141 backcmd->nleft = memout.nextc - memout.buf; 1142 memout.buf = NULL; 1143 } 1144 if (cmdentry.u.index != EXECCMD) 1145 popredir(); 1146 if (e != -1) { 1147 if ((e != EXERROR && e != EXEXEC) 1148 || cmdentry.special) 1149 exraise(e); 1150 popfilesupto(savetopfile); 1151 if (flags != EV_BACKCMD) 1152 FORCEINTON; 1153 } 1154 } else { 1155 #ifdef DEBUG 1156 trputs("normal command: "); trargs(argv); 1157 #endif 1158 redirect(cmd->ncmd.redirect, 0); 1159 for (sp = varlist.list ; sp ; sp = sp->next) 1160 setvareq(sp->text, VEXPORT|VSTACK); 1161 envp = environment(); 1162 shellexec(argv, envp, path, cmdentry.u.index); 1163 /*NOTREACHED*/ 1164 } 1165 goto out; 1166 1167 parent: /* parent process gets here (if we forked) */ 1168 if (mode == FORK_FG) { /* argument to fork */ 1169 INTOFF; 1170 exitstatus = waitforjob(jp, &realstatus); 1171 INTON; 1172 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1173 evalskip = SKIPBREAK; 1174 skipcount = loopnest; 1175 } 1176 } else if (mode == FORK_NOJOB) { 1177 backcmd->fd = pip[0]; 1178 close(pip[1]); 1179 backcmd->jp = jp; 1180 } 1181 1182 out: 1183 if (lastarg) 1184 setvar("_", lastarg, 0); 1185 if (do_clearcmdentry) 1186 clearcmdentry(); 1187 } 1188 1189 1190 1191 /* 1192 * Search for a command. This is called before we fork so that the 1193 * location of the command will be available in the parent as well as 1194 * the child. The check for "goodname" is an overly conservative 1195 * check that the name will not be subject to expansion. 1196 */ 1197 1198 static void 1199 prehash(union node *n) 1200 { 1201 struct cmdentry entry; 1202 1203 if (n && n->type == NCMD && n->ncmd.args) 1204 if (goodname(n->ncmd.args->narg.text)) 1205 find_command(n->ncmd.args->narg.text, &entry, 0, 1206 pathval()); 1207 } 1208 1209 1210 1211 /* 1212 * Builtin commands. Builtin commands whose functions are closely 1213 * tied to evaluation are implemented here. 1214 */ 1215 1216 /* 1217 * No command given, a bltin command with no arguments, or a bltin command 1218 * with an invalid name. 1219 */ 1220 1221 int 1222 bltincmd(int argc, char **argv) 1223 { 1224 if (argc > 1) { 1225 out2fmt_flush("%s: not found\n", argv[1]); 1226 return 127; 1227 } 1228 /* 1229 * Preserve exitstatus of a previous possible redirection 1230 * as POSIX mandates 1231 */ 1232 return exitstatus; 1233 } 1234 1235 1236 /* 1237 * Handle break and continue commands. Break, continue, and return are 1238 * all handled by setting the evalskip flag. The evaluation routines 1239 * above all check this flag, and if it is set they start skipping 1240 * commands rather than executing them. The variable skipcount is 1241 * the number of loops to break/continue, or the number of function 1242 * levels to return. (The latter is always 1.) It should probably 1243 * be an error to break out of more loops than exist, but it isn't 1244 * in the standard shell so we don't make it one here. 1245 */ 1246 1247 int 1248 breakcmd(int argc, char **argv) 1249 { 1250 int n = argc > 1 ? number(argv[1]) : 1; 1251 1252 if (n > loopnest) 1253 n = loopnest; 1254 if (n > 0) { 1255 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1256 skipcount = n; 1257 } 1258 return 0; 1259 } 1260 1261 /* 1262 * The `command' command. 1263 */ 1264 int 1265 commandcmd(int argc __unused, char **argv __unused) 1266 { 1267 const char *path; 1268 int ch; 1269 int cmd = -1; 1270 1271 path = bltinlookup("PATH", 1); 1272 1273 while ((ch = nextopt("pvV")) != '\0') { 1274 switch (ch) { 1275 case 'p': 1276 path = _PATH_STDPATH; 1277 break; 1278 case 'v': 1279 cmd = TYPECMD_SMALLV; 1280 break; 1281 case 'V': 1282 cmd = TYPECMD_BIGV; 1283 break; 1284 } 1285 } 1286 1287 if (cmd != -1) { 1288 if (*argptr == NULL || argptr[1] != NULL) 1289 error("wrong number of arguments"); 1290 return typecmd_impl(2, argptr - 1, cmd, path); 1291 } 1292 if (*argptr != NULL) 1293 error("commandcmd bad call"); 1294 1295 /* 1296 * Do nothing successfully if no command was specified; 1297 * ksh also does this. 1298 */ 1299 return(0); 1300 } 1301 1302 1303 /* 1304 * The return command. 1305 */ 1306 1307 int 1308 returncmd(int argc, char **argv) 1309 { 1310 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1311 1312 if (funcnest) { 1313 evalskip = SKIPFUNC; 1314 skipcount = 1; 1315 } else { 1316 /* skip the rest of the file */ 1317 evalskip = SKIPFILE; 1318 skipcount = 1; 1319 } 1320 return ret; 1321 } 1322 1323 1324 int 1325 falsecmd(int argc __unused, char **argv __unused) 1326 { 1327 return 1; 1328 } 1329 1330 1331 int 1332 truecmd(int argc __unused, char **argv __unused) 1333 { 1334 return 0; 1335 } 1336 1337 1338 int 1339 execcmd(int argc, char **argv) 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 struct strlist *sp; 1349 1350 iflag = 0; /* exit on error */ 1351 mflag = 0; 1352 optschanged(); 1353 for (sp = cmdenviron; sp ; sp = sp->next) 1354 setvareq(sp->text, VEXPORT|VSTACK); 1355 shellexec(argv + 1, environment(), pathval(), 0); 1356 1357 } 1358 return 0; 1359 } 1360 1361 1362 int 1363 timescmd(int argc __unused, char **argv __unused) 1364 { 1365 struct rusage ru; 1366 long shumins, shsmins, chumins, chsmins; 1367 double shusecs, shssecs, chusecs, chssecs; 1368 1369 if (getrusage(RUSAGE_SELF, &ru) < 0) 1370 return 1; 1371 shumins = ru.ru_utime.tv_sec / 60; 1372 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1373 shsmins = ru.ru_stime.tv_sec / 60; 1374 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1375 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1376 return 1; 1377 chumins = ru.ru_utime.tv_sec / 60; 1378 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1379 chsmins = ru.ru_stime.tv_sec / 60; 1380 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1381 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1382 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1383 return 0; 1384 } 1385