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: src/bin/sh/eval.c,v 1.101 2011/02/05 14:08:51 jilles Exp $ 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 static 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 void evalcase(union node *, int); 94 static void evalsubshell(union node *, int); 95 static void evalredir(union node *, int); 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 #ifdef mkinit 108 INCLUDE "eval.h" 109 110 RESET { 111 evalskip = 0; 112 loopnest = 0; 113 funcnest = 0; 114 } 115 #endif 116 117 118 119 /* 120 * The eval command. 121 */ 122 123 int 124 evalcmd(int argc, char **argv) 125 { 126 char *p; 127 char *concat; 128 char **ap; 129 130 if (argc > 1) { 131 p = argv[1]; 132 if (argc > 2) { 133 STARTSTACKSTR(concat); 134 ap = argv + 2; 135 for (;;) { 136 STPUTS(p, concat); 137 if ((p = *ap++) == NULL) 138 break; 139 STPUTC(' ', concat); 140 } 141 STPUTC('\0', concat); 142 p = grabstackstr(concat); 143 } 144 evalstring(p, builtin_flags & EV_TESTED); 145 } else 146 exitstatus = 0; 147 return exitstatus; 148 } 149 150 151 /* 152 * Execute a command or commands contained in a string. 153 */ 154 155 void 156 evalstring(char *s, int flags) 157 { 158 union node *n; 159 struct stackmark smark; 160 int flags_exit; 161 int any; 162 163 flags_exit = flags & EV_EXIT; 164 flags &= ~EV_EXIT; 165 any = 0; 166 setstackmark(&smark); 167 setinputstring(s, 1); 168 while ((n = parsecmd(0)) != NEOF) { 169 if (n != NULL) { 170 if (flags_exit && preadateof()) 171 evaltree(n, flags | EV_EXIT); 172 else 173 evaltree(n, flags); 174 any = 1; 175 } 176 popstackmark(&smark); 177 } 178 popfile(); 179 popstackmark(&smark); 180 if (!any) 181 exitstatus = 0; 182 if (flags_exit) 183 exitshell(exitstatus); 184 } 185 186 187 /* 188 * Evaluate a parse tree. The value is left in the global variable 189 * exitstatus. 190 */ 191 192 void 193 evaltree(union node *n, int flags) 194 { 195 int do_etest; 196 union node *next; 197 198 do_etest = 0; 199 if (n == NULL) { 200 TRACE(("evaltree(NULL) called\n")); 201 exitstatus = 0; 202 goto out; 203 } 204 do { 205 next = NULL; 206 #ifndef NO_HISTORY 207 displayhist = 1; /* show history substitutions done with fc */ 208 #endif 209 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 210 switch (n->type) { 211 case NSEMI: 212 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 213 if (evalskip) 214 goto out; 215 next = n->nbinary.ch2; 216 break; 217 case NAND: 218 evaltree(n->nbinary.ch1, EV_TESTED); 219 if (evalskip || exitstatus != 0) { 220 goto out; 221 } 222 next = n->nbinary.ch2; 223 break; 224 case NOR: 225 evaltree(n->nbinary.ch1, EV_TESTED); 226 if (evalskip || exitstatus == 0) 227 goto out; 228 next = n->nbinary.ch2; 229 break; 230 case NREDIR: 231 evalredir(n, flags); 232 break; 233 case NSUBSHELL: 234 evalsubshell(n, flags); 235 do_etest = !(flags & EV_TESTED); 236 break; 237 case NBACKGND: 238 evalsubshell(n, flags); 239 break; 240 case NIF: { 241 evaltree(n->nif.test, EV_TESTED); 242 if (evalskip) 243 goto out; 244 if (exitstatus == 0) 245 next = n->nif.ifpart; 246 else if (n->nif.elsepart) 247 next = n->nif.elsepart; 248 else 249 exitstatus = 0; 250 break; 251 } 252 case NWHILE: 253 case NUNTIL: 254 evalloop(n, flags & ~EV_EXIT); 255 break; 256 case NFOR: 257 evalfor(n, flags & ~EV_EXIT); 258 break; 259 case NCASE: 260 evalcase(n, flags); 261 break; 262 case NDEFUN: 263 defun(n->narg.text, n->narg.next); 264 exitstatus = 0; 265 break; 266 case NNOT: 267 evaltree(n->nnot.com, EV_TESTED); 268 exitstatus = !exitstatus; 269 break; 270 271 case NPIPE: 272 evalpipe(n); 273 do_etest = !(flags & EV_TESTED); 274 break; 275 case NCMD: 276 evalcommand(n, flags, NULL); 277 do_etest = !(flags & EV_TESTED); 278 break; 279 default: 280 out1fmt("Node type = %d\n", n->type); 281 flushout(&output); 282 break; 283 } 284 n = next; 285 } while (n != NULL); 286 out: 287 if (pendingsigs) 288 dotrap(); 289 if ((flags & EV_EXIT) || (eflag && exitstatus != 0 && do_etest)) 290 exitshell(exitstatus); 291 } 292 293 294 static void 295 evalloop(union node *n, int flags) 296 { 297 int status; 298 299 loopnest++; 300 status = 0; 301 for (;;) { 302 evaltree(n->nbinary.ch1, EV_TESTED); 303 if (evalskip) { 304 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 305 evalskip = 0; 306 continue; 307 } 308 if (evalskip == SKIPBREAK && --skipcount <= 0) 309 evalskip = 0; 310 if (evalskip == SKIPFUNC || evalskip == SKIPFILE) 311 status = exitstatus; 312 break; 313 } 314 if (n->type == NWHILE) { 315 if (exitstatus != 0) 316 break; 317 } else { 318 if (exitstatus == 0) 319 break; 320 } 321 evaltree(n->nbinary.ch2, flags); 322 status = exitstatus; 323 if (evalskip) 324 goto skipping; 325 } 326 loopnest--; 327 exitstatus = status; 328 } 329 330 331 332 static void 333 evalfor(union node *n, int flags) 334 { 335 struct arglist arglist; 336 union node *argp; 337 struct strlist *sp; 338 struct stackmark smark; 339 340 setstackmark(&smark); 341 arglist.lastp = &arglist.list; 342 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 343 oexitstatus = exitstatus; 344 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 345 if (evalskip) 346 goto out; 347 } 348 *arglist.lastp = NULL; 349 350 exitstatus = 0; 351 loopnest++; 352 for (sp = arglist.list ; sp ; sp = sp->next) { 353 setvar(n->nfor.var, sp->text, 0); 354 evaltree(n->nfor.body, flags); 355 if (evalskip) { 356 if (evalskip == SKIPCONT && --skipcount <= 0) { 357 evalskip = 0; 358 continue; 359 } 360 if (evalskip == SKIPBREAK && --skipcount <= 0) 361 evalskip = 0; 362 break; 363 } 364 } 365 loopnest--; 366 out: 367 popstackmark(&smark); 368 } 369 370 371 372 static void 373 evalcase(union node *n, int flags) 374 { 375 union node *cp; 376 union node *patp; 377 struct arglist arglist; 378 struct stackmark smark; 379 380 setstackmark(&smark); 381 arglist.lastp = &arglist.list; 382 oexitstatus = exitstatus; 383 exitstatus = 0; 384 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 385 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 386 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 387 if (casematch(patp, arglist.list->text)) { 388 if (evalskip == 0) { 389 evaltree(cp->nclist.body, flags); 390 } 391 goto out; 392 } 393 } 394 } 395 out: 396 popstackmark(&smark); 397 } 398 399 400 401 /* 402 * Kick off a subshell to evaluate a tree. 403 */ 404 405 static void 406 evalsubshell(union node *n, int flags) 407 { 408 struct job *jp; 409 int backgnd = (n->type == NBACKGND); 410 411 expredir(n->nredir.redirect); 412 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 413 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 414 if (backgnd) 415 flags &=~ EV_TESTED; 416 redirect(n->nredir.redirect, 0); 417 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 418 } else if (!backgnd) { 419 INTOFF; 420 exitstatus = waitforjob(jp, NULL); 421 INTON; 422 } 423 } 424 425 426 /* 427 * Evaluate a redirected compound command. 428 */ 429 430 static void 431 evalredir(union node *n, int flags) 432 { 433 struct jmploc jmploc; 434 struct jmploc *savehandler; 435 volatile int in_redirect = 1; 436 437 expredir(n->nredir.redirect); 438 savehandler = handler; 439 if (setjmp(jmploc.loc)) { 440 int e; 441 442 handler = savehandler; 443 e = exception; 444 if (e == EXERROR || e == EXEXEC) { 445 popredir(); 446 if (in_redirect) { 447 exitstatus = 2; 448 return; 449 } 450 } 451 longjmp(handler->loc, 1); 452 } else { 453 INTOFF; 454 handler = &jmploc; 455 redirect(n->nredir.redirect, REDIR_PUSH); 456 in_redirect = 0; 457 INTON; 458 evaltree(n->nredir.n, flags); 459 } 460 INTOFF; 461 handler = savehandler; 462 popredir(); 463 INTON; 464 } 465 466 467 /* 468 * Compute the names of the files in a redirection list. 469 */ 470 471 static void 472 expredir(union node *n) 473 { 474 union node *redir; 475 476 for (redir = n ; redir ; redir = redir->nfile.next) { 477 struct arglist fn; 478 fn.lastp = &fn.list; 479 oexitstatus = exitstatus; 480 switch (redir->type) { 481 case NFROM: 482 case NTO: 483 case NFROMTO: 484 case NAPPEND: 485 case NCLOBBER: 486 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 487 redir->nfile.expfname = fn.list->text; 488 break; 489 case NFROMFD: 490 case NTOFD: 491 if (redir->ndup.vname) { 492 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 493 fixredir(redir, fn.list->text, 1); 494 } 495 break; 496 } 497 } 498 } 499 500 501 502 /* 503 * Evaluate a pipeline. All the processes in the pipeline are children 504 * of the process creating the pipeline. (This differs from some versions 505 * of the shell, which make the last process in a pipeline the parent 506 * of all the rest.) 507 */ 508 509 static void 510 evalpipe(union node *n) 511 { 512 struct job *jp; 513 struct nodelist *lp; 514 int pipelen; 515 int prevfd; 516 int pip[2]; 517 518 TRACE(("evalpipe(%p) called\n", (void *)n)); 519 pipelen = 0; 520 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 521 pipelen++; 522 INTOFF; 523 jp = makejob(n, pipelen); 524 prevfd = -1; 525 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 526 prehash(lp->n); 527 pip[1] = -1; 528 if (lp->next) { 529 if (pipe(pip) < 0) { 530 if (prevfd >= 0) 531 close(prevfd); 532 error("Pipe call failed: %s", strerror(errno)); 533 } 534 } 535 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 536 INTON; 537 if (prevfd > 0) { 538 dup2(prevfd, 0); 539 close(prevfd); 540 } 541 if (pip[1] >= 0) { 542 if (!(prevfd >= 0 && pip[0] == 0)) 543 close(pip[0]); 544 if (pip[1] != 1) { 545 dup2(pip[1], 1); 546 close(pip[1]); 547 } 548 } 549 evaltree(lp->n, EV_EXIT); 550 } 551 if (prevfd >= 0) 552 close(prevfd); 553 prevfd = pip[0]; 554 close(pip[1]); 555 } 556 INTON; 557 if (n->npipe.backgnd == 0) { 558 INTOFF; 559 exitstatus = waitforjob(jp, NULL); 560 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 561 INTON; 562 } 563 } 564 565 566 567 static int 568 is_valid_fast_cmdsubst(union node *n) 569 { 570 union node *argp; 571 572 if (n->type != NCMD) 573 return 0; 574 for (argp = n->ncmd.args ; argp ; argp = argp->narg.next) 575 if (expandhassideeffects(argp->narg.text)) 576 return 0; 577 return 1; 578 } 579 580 /* 581 * Execute a command inside back quotes. If it's a builtin command, we 582 * want to save its output in a block obtained from malloc. Otherwise 583 * we fork off a subprocess and get the output of the command via a pipe. 584 * Should be called with interrupts off. 585 */ 586 587 void 588 evalbackcmd(union node *n, struct backcmd *result) 589 { 590 int pip[2]; 591 struct job *jp; 592 struct stackmark smark; /* unnecessary */ 593 struct jmploc jmploc; 594 struct jmploc *savehandler; 595 596 setstackmark(&smark); 597 result->fd = -1; 598 result->buf = NULL; 599 result->nleft = 0; 600 result->jp = NULL; 601 if (n == NULL) { 602 exitstatus = 0; 603 goto out; 604 } 605 if (is_valid_fast_cmdsubst(n)) { 606 exitstatus = oexitstatus; 607 savehandler = handler; 608 if (setjmp(jmploc.loc)) { 609 if (exception == EXERROR || exception == EXEXEC) 610 exitstatus = 2; 611 else if (exception != 0) { 612 handler = savehandler; 613 longjmp(handler->loc, 1); 614 } 615 } else { 616 handler = &jmploc; 617 evalcommand(n, EV_BACKCMD, result); 618 } 619 handler = savehandler; 620 } else { 621 exitstatus = 0; 622 if (pipe(pip) < 0) 623 error("Pipe call failed: %s", strerror(errno)); 624 jp = makejob(n, 1); 625 if (forkshell(jp, n, FORK_NOJOB) == 0) { 626 FORCEINTON; 627 close(pip[0]); 628 if (pip[1] != 1) { 629 dup2(pip[1], 1); 630 close(pip[1]); 631 } 632 evaltree(n, EV_EXIT); 633 } 634 close(pip[1]); 635 result->fd = pip[0]; 636 result->jp = jp; 637 } 638 out: 639 popstackmark(&smark); 640 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 641 result->fd, result->buf, result->nleft, result->jp)); 642 } 643 644 /* 645 * Check if a builtin can safely be executed in the same process, 646 * even though it should be in a subshell (command substitution). 647 * Note that jobid, jobs, times and trap can show information not 648 * available in a child process; this is deliberate. 649 * The arguments should already have been expanded. 650 */ 651 static int 652 safe_builtin(int idx, int argc, char **argv) 653 { 654 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 655 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 656 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 657 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 658 idx == TYPECMD) 659 return (1); 660 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 661 idx == UMASKCMD) 662 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 663 if (idx == SETCMD) 664 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 665 argv[1][0] == '+') && argv[1][1] == 'o' && 666 argv[1][2] == '\0')); 667 return (0); 668 } 669 670 /* 671 * Execute a simple command. 672 * Note: This may or may not return if (flags & EV_EXIT). 673 */ 674 675 static void 676 evalcommand(union node *cmd, int flgs, struct backcmd *backcmd) 677 { 678 struct stackmark smark; 679 union node *argp; 680 struct arglist arglist; 681 struct arglist varlist; 682 volatile int flags = flgs; 683 char **volatile argv; 684 volatile int argc; 685 char **envp; 686 int varflag; 687 struct strlist *sp; 688 int mode; 689 int pip[2]; 690 struct cmdentry cmdentry; 691 struct job *volatile jp; 692 struct jmploc jmploc; 693 struct jmploc *savehandler; 694 const char *savecmdname; 695 struct shparam saveparam; 696 struct localvar *savelocalvars; 697 struct parsefile *savetopfile; 698 volatile int e; 699 char *volatile lastarg; 700 int realstatus; 701 volatile int do_clearcmdentry; 702 const char *path = pathval(); 703 704 /* First expand the arguments. */ 705 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 706 setstackmark(&smark); 707 arglist.lastp = &arglist.list; 708 varlist.lastp = &varlist.list; 709 varflag = 1; 710 jp = NULL; 711 do_clearcmdentry = 0; 712 oexitstatus = exitstatus; 713 exitstatus = 0; 714 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 715 char *p = argp->narg.text; 716 if (varflag && is_name(*p)) { 717 do { 718 p++; 719 } while (is_in_name(*p)); 720 if (*p == '=') { 721 expandarg(argp, &varlist, EXP_VARTILDE); 722 continue; 723 } 724 } 725 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 726 varflag = 0; 727 } 728 *arglist.lastp = NULL; 729 *varlist.lastp = NULL; 730 expredir(cmd->ncmd.redirect); 731 argc = 0; 732 for (sp = arglist.list ; sp ; sp = sp->next) 733 argc++; 734 /* Add one slot at the beginning for tryexec(). */ 735 argv = stalloc(sizeof (char *) * (argc + 2)); 736 argv++; 737 738 for (sp = arglist.list ; sp ; sp = sp->next) { 739 TRACE(("evalcommand arg: %s\n", sp->text)); 740 *argv++ = sp->text; 741 } 742 *argv = NULL; 743 lastarg = NULL; 744 if (iflag && funcnest == 0 && argc > 0) 745 lastarg = argv[-1]; 746 argv -= argc; 747 748 /* Print the command if xflag is set. */ 749 if (xflag) { 750 char sep = 0; 751 const char *p; 752 out2str(ps4val()); 753 for (sp = varlist.list ; sp ; sp = sp->next) { 754 if (sep != 0) 755 out2c(' '); 756 p = strchr(sp->text, '='); 757 if (p != NULL) { 758 p++; 759 outbin(sp->text, p - sp->text, out2); 760 out2qstr(p); 761 } else 762 out2qstr(sp->text); 763 sep = ' '; 764 } 765 for (sp = arglist.list ; sp ; sp = sp->next) { 766 if (sep != 0) 767 out2c(' '); 768 /* Disambiguate command looking like assignment. */ 769 if (sp == arglist.list && 770 strchr(sp->text, '=') != NULL && 771 strchr(sp->text, '\'') == NULL) { 772 out2c('\''); 773 out2str(sp->text); 774 out2c('\''); 775 } else 776 out2qstr(sp->text); 777 sep = ' '; 778 } 779 out2c('\n'); 780 flushout(&errout); 781 } 782 783 /* Now locate the command. */ 784 if (argc == 0) { 785 /* Variable assignment(s) without command */ 786 cmdentry.cmdtype = CMDBUILTIN; 787 cmdentry.u.index = BLTINCMD; 788 cmdentry.special = 0; 789 } else { 790 static const char PATH[] = "PATH="; 791 int cmd_flags = 0, bltinonly = 0; 792 793 /* 794 * Modify the command lookup path, if a PATH= assignment 795 * is present 796 */ 797 for (sp = varlist.list ; sp ; sp = sp->next) 798 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 799 path = sp->text + sizeof(PATH) - 1; 800 /* 801 * On `PATH=... command`, we need to make 802 * sure that the command isn't using the 803 * non-updated hash table of the outer PATH 804 * setting and we need to make sure that 805 * the hash table isn't filled with items 806 * from the temporary setting. 807 * 808 * It would be better to forbit using and 809 * updating the table while this command 810 * runs, by the command finding mechanism 811 * is heavily integrated with hash handling, 812 * so we just delete the hash before and after 813 * the command runs. Partly deleting like 814 * changepatch() does doesn't seem worth the 815 * bookinging effort, since most such runs add 816 * directories in front of the new PATH. 817 */ 818 clearcmdentry(); 819 do_clearcmdentry = 1; 820 } 821 822 for (;;) { 823 if (bltinonly) { 824 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 825 if (cmdentry.u.index < 0) { 826 cmdentry.u.index = BLTINCMD; 827 argv--; 828 argc++; 829 break; 830 } 831 } else 832 find_command(argv[0], &cmdentry, cmd_flags, path); 833 /* implement the bltin and command builtins here */ 834 if (cmdentry.cmdtype != CMDBUILTIN) 835 break; 836 if (cmdentry.u.index == BLTINCMD) { 837 if (argc == 1) 838 break; 839 argv++; 840 argc--; 841 bltinonly = 1; 842 } else if (cmdentry.u.index == COMMANDCMD) { 843 if (argc == 1) 844 break; 845 if (!strcmp(argv[1], "-p")) { 846 if (argc == 2) 847 break; 848 if (argv[2][0] == '-') { 849 if (strcmp(argv[2], "--")) 850 break; 851 if (argc == 3) 852 break; 853 argv += 3; 854 argc -= 3; 855 } else { 856 argv += 2; 857 argc -= 2; 858 } 859 path = _PATH_STDPATH; 860 clearcmdentry(); 861 do_clearcmdentry = 1; 862 } else if (!strcmp(argv[1], "--")) { 863 if (argc == 2) 864 break; 865 argv += 2; 866 argc -= 2; 867 } else if (argv[1][0] == '-') 868 break; 869 else { 870 argv++; 871 argc--; 872 } 873 cmd_flags |= DO_NOFUNC; 874 bltinonly = 0; 875 } else 876 break; 877 } 878 /* 879 * Special builtins lose their special properties when 880 * called via 'command'. 881 */ 882 if (cmd_flags & DO_NOFUNC) 883 cmdentry.special = 0; 884 } 885 886 /* Fork off a child process if necessary. */ 887 if (cmd->ncmd.backgnd 888 || ((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 889 && ((flags & EV_EXIT) == 0 || have_traps())) 890 || ((flags & EV_BACKCMD) != 0 891 && (cmdentry.cmdtype != CMDBUILTIN || 892 !safe_builtin(cmdentry.u.index, argc, argv)))) { 893 jp = makejob(cmd, 1); 894 mode = cmd->ncmd.backgnd; 895 if (flags & EV_BACKCMD) { 896 mode = FORK_NOJOB; 897 if (pipe(pip) < 0) 898 error("Pipe call failed: %s", strerror(errno)); 899 } 900 if (forkshell(jp, cmd, mode) != 0) 901 goto parent; /* at end of routine */ 902 if (flags & EV_BACKCMD) { 903 FORCEINTON; 904 close(pip[0]); 905 if (pip[1] != 1) { 906 dup2(pip[1], 1); 907 close(pip[1]); 908 } 909 } 910 flags |= EV_EXIT; 911 } 912 913 /* This is the child process if a fork occurred. */ 914 /* Execute the command. */ 915 if (cmdentry.cmdtype == CMDFUNCTION) { 916 #ifdef DEBUG 917 trputs("Shell function: "); trargs(argv); 918 #endif 919 saveparam = shellparam; 920 shellparam.malloc = 0; 921 shellparam.reset = 1; 922 shellparam.nparam = argc - 1; 923 shellparam.p = argv + 1; 924 shellparam.optnext = NULL; 925 INTOFF; 926 savelocalvars = localvars; 927 localvars = NULL; 928 reffunc(cmdentry.u.func); 929 savehandler = handler; 930 if (setjmp(jmploc.loc)) { 931 freeparam(&shellparam); 932 shellparam = saveparam; 933 if (exception == EXERROR || exception == EXEXEC) 934 popredir(); 935 unreffunc(cmdentry.u.func); 936 poplocalvars(); 937 localvars = savelocalvars; 938 funcnest--; 939 handler = savehandler; 940 longjmp(handler->loc, 1); 941 } 942 handler = &jmploc; 943 funcnest++; 944 redirect(cmd->ncmd.redirect, REDIR_PUSH); 945 INTON; 946 for (sp = varlist.list ; sp ; sp = sp->next) 947 mklocal(sp->text); 948 exitstatus = oexitstatus; 949 if (flags & EV_TESTED) 950 evaltree(getfuncnode(cmdentry.u.func), EV_TESTED); 951 else 952 evaltree(getfuncnode(cmdentry.u.func), 0); 953 INTOFF; 954 unreffunc(cmdentry.u.func); 955 poplocalvars(); 956 localvars = savelocalvars; 957 freeparam(&shellparam); 958 shellparam = saveparam; 959 handler = savehandler; 960 funcnest--; 961 popredir(); 962 INTON; 963 if (evalskip == SKIPFUNC) { 964 evalskip = 0; 965 skipcount = 0; 966 } 967 if (jp) 968 exitshell(exitstatus); 969 } else if (cmdentry.cmdtype == CMDBUILTIN) { 970 #ifdef DEBUG 971 trputs("builtin command: "); trargs(argv); 972 #endif 973 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 974 if (flags == EV_BACKCMD) { 975 memout.nleft = 0; 976 memout.nextc = memout.buf; 977 memout.bufsize = 64; 978 mode |= REDIR_BACKQ; 979 cmdentry.special = 0; 980 } 981 savecmdname = commandname; 982 savetopfile = getcurrentfile(); 983 cmdenviron = varlist.list; 984 e = -1; 985 savehandler = handler; 986 if (setjmp(jmploc.loc)) { 987 e = exception; 988 exitstatus = (e == EXINT)? SIGINT+128 : 2; 989 goto cmddone; 990 } 991 handler = &jmploc; 992 redirect(cmd->ncmd.redirect, mode); 993 /* 994 * If there is no command word, redirection errors should 995 * not be fatal but assignment errors should. 996 */ 997 if (argc == 0 && !(flags & EV_BACKCMD)) 998 cmdentry.special = 1; 999 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1000 if (argc > 0) 1001 bltinsetlocale(); 1002 commandname = argv[0]; 1003 argptr = argv + 1; 1004 nextopt_optptr = NULL; /* initialize nextopt */ 1005 builtin_flags = flags; 1006 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1007 flushall(); 1008 cmddone: 1009 if (argc > 0) 1010 bltinunsetlocale(); 1011 cmdenviron = NULL; 1012 out1 = &output; 1013 out2 = &errout; 1014 freestdout(); 1015 handler = savehandler; 1016 commandname = savecmdname; 1017 if (jp) 1018 exitshell(exitstatus); 1019 if (flags == EV_BACKCMD) { 1020 backcmd->buf = memout.buf; 1021 backcmd->nleft = memout.nextc - memout.buf; 1022 memout.buf = NULL; 1023 } 1024 if (cmdentry.u.index != EXECCMD && 1025 (e == -1 || e == EXERROR || e == EXEXEC)) 1026 popredir(); 1027 if (e != -1) { 1028 if ((e != EXERROR && e != EXEXEC) 1029 || cmdentry.special) 1030 exraise(e); 1031 popfilesupto(savetopfile); 1032 if (flags != EV_BACKCMD) 1033 FORCEINTON; 1034 } 1035 } else { 1036 #ifdef DEBUG 1037 trputs("normal command: "); trargs(argv); 1038 #endif 1039 redirect(cmd->ncmd.redirect, 0); 1040 for (sp = varlist.list ; sp ; sp = sp->next) 1041 setvareq(sp->text, VEXPORT|VSTACK); 1042 envp = environment(); 1043 shellexec(argv, envp, path, cmdentry.u.index); 1044 /*NOTREACHED*/ 1045 } 1046 goto out; 1047 1048 parent: /* parent process gets here (if we forked) */ 1049 if (mode == FORK_FG) { /* argument to fork */ 1050 INTOFF; 1051 exitstatus = waitforjob(jp, &realstatus); 1052 INTON; 1053 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1054 evalskip = SKIPBREAK; 1055 skipcount = loopnest; 1056 } 1057 } else if (mode == FORK_NOJOB) { 1058 backcmd->fd = pip[0]; 1059 close(pip[1]); 1060 backcmd->jp = jp; 1061 } 1062 1063 out: 1064 if (lastarg) 1065 setvar("_", lastarg, 0); 1066 if (do_clearcmdentry) 1067 clearcmdentry(); 1068 popstackmark(&smark); 1069 } 1070 1071 1072 1073 /* 1074 * Search for a command. This is called before we fork so that the 1075 * location of the command will be available in the parent as well as 1076 * the child. The check for "goodname" is an overly conservative 1077 * check that the name will not be subject to expansion. 1078 */ 1079 1080 static void 1081 prehash(union node *n) 1082 { 1083 struct cmdentry entry; 1084 1085 if (n && n->type == NCMD && n->ncmd.args) 1086 if (goodname(n->ncmd.args->narg.text)) 1087 find_command(n->ncmd.args->narg.text, &entry, 0, 1088 pathval()); 1089 } 1090 1091 1092 1093 /* 1094 * Builtin commands. Builtin commands whose functions are closely 1095 * tied to evaluation are implemented here. 1096 */ 1097 1098 /* 1099 * No command given, a bltin command with no arguments, or a bltin command 1100 * with an invalid name. 1101 */ 1102 1103 int 1104 bltincmd(int argc, char **argv) 1105 { 1106 if (argc > 1) { 1107 out2fmt_flush("%s: not found\n", argv[1]); 1108 return 127; 1109 } 1110 /* 1111 * Preserve exitstatus of a previous possible redirection 1112 * as POSIX mandates 1113 */ 1114 return exitstatus; 1115 } 1116 1117 1118 /* 1119 * Handle break and continue commands. Break, continue, and return are 1120 * all handled by setting the evalskip flag. The evaluation routines 1121 * above all check this flag, and if it is set they start skipping 1122 * commands rather than executing them. The variable skipcount is 1123 * the number of loops to break/continue, or the number of function 1124 * levels to return. (The latter is always 1.) It should probably 1125 * be an error to break out of more loops than exist, but it isn't 1126 * in the standard shell so we don't make it one here. 1127 */ 1128 1129 int 1130 breakcmd(int argc, char **argv) 1131 { 1132 int n = argc > 1 ? number(argv[1]) : 1; 1133 1134 if (n > loopnest) 1135 n = loopnest; 1136 if (n > 0) { 1137 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1138 skipcount = n; 1139 } 1140 return 0; 1141 } 1142 1143 /* 1144 * The `command' command. 1145 */ 1146 int 1147 commandcmd(int argc, char **argv) 1148 { 1149 const char *path; 1150 int ch; 1151 int cmd = -1; 1152 1153 path = bltinlookup("PATH", 1); 1154 1155 optind = optreset = 1; 1156 opterr = 0; 1157 while ((ch = getopt(argc, argv, "pvV")) != -1) { 1158 switch (ch) { 1159 case 'p': 1160 path = _PATH_STDPATH; 1161 break; 1162 case 'v': 1163 cmd = TYPECMD_SMALLV; 1164 break; 1165 case 'V': 1166 cmd = TYPECMD_BIGV; 1167 break; 1168 case '?': 1169 default: 1170 error("unknown option: -%c", optopt); 1171 } 1172 } 1173 argc -= optind; 1174 argv += optind; 1175 1176 if (cmd != -1) { 1177 if (argc != 1) 1178 error("wrong number of arguments"); 1179 return typecmd_impl(2, argv - 1, cmd, path); 1180 } 1181 if (argc != 0) 1182 error("commandcmd bad call"); 1183 1184 /* 1185 * Do nothing successfully if no command was specified; 1186 * ksh also does this. 1187 */ 1188 return(0); 1189 } 1190 1191 1192 /* 1193 * The return command. 1194 */ 1195 1196 int 1197 returncmd(int argc, char **argv) 1198 { 1199 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1200 1201 if (funcnest) { 1202 evalskip = SKIPFUNC; 1203 skipcount = 1; 1204 } else { 1205 /* skip the rest of the file */ 1206 evalskip = SKIPFILE; 1207 skipcount = 1; 1208 } 1209 return ret; 1210 } 1211 1212 1213 int 1214 falsecmd(int argc __unused, char **argv __unused) 1215 { 1216 return 1; 1217 } 1218 1219 1220 int 1221 truecmd(int argc __unused, char **argv __unused) 1222 { 1223 return 0; 1224 } 1225 1226 1227 int 1228 execcmd(int argc, char **argv) 1229 { 1230 /* 1231 * Because we have historically not supported any options, 1232 * only treat "--" specially. 1233 */ 1234 if (argc > 1 && strcmp(argv[1], "--") == 0) 1235 argc--, argv++; 1236 if (argc > 1) { 1237 struct strlist *sp; 1238 1239 iflag = 0; /* exit on error */ 1240 mflag = 0; 1241 optschanged(); 1242 for (sp = cmdenviron; sp ; sp = sp->next) 1243 setvareq(sp->text, VEXPORT|VSTACK); 1244 shellexec(argv + 1, environment(), pathval(), 0); 1245 1246 } 1247 return 0; 1248 } 1249 1250 1251 int 1252 timescmd(int argc __unused, char **argv __unused) 1253 { 1254 struct rusage ru; 1255 long shumins, shsmins, chumins, chsmins; 1256 double shusecs, shssecs, chusecs, chssecs; 1257 1258 if (getrusage(RUSAGE_SELF, &ru) < 0) 1259 return 1; 1260 shumins = ru.ru_utime.tv_sec / 60; 1261 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1262 shsmins = ru.ru_stime.tv_sec / 60; 1263 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1264 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1265 return 1; 1266 chumins = ru.ru_utime.tv_sec / 60; 1267 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1268 chsmins = ru.ru_stime.tv_sec / 60; 1269 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1270 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1271 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1272 return 0; 1273 } 1274