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