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 1.103 2011/04/25 20:54:12 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 exraise(EXEXIT); 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 (eflag && exitstatus != 0 && do_etest) 290 exitshell(exitstatus); 291 if (flags & EV_EXIT) 292 exraise(EXEXIT); 293 } 294 295 296 static void 297 evalloop(union node *n, int flags) 298 { 299 int status; 300 301 loopnest++; 302 status = 0; 303 for (;;) { 304 evaltree(n->nbinary.ch1, EV_TESTED); 305 if (evalskip) { 306 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 307 evalskip = 0; 308 continue; 309 } 310 if (evalskip == SKIPBREAK && --skipcount <= 0) 311 evalskip = 0; 312 if (evalskip == SKIPFUNC || evalskip == SKIPFILE) 313 status = exitstatus; 314 break; 315 } 316 if (n->type == NWHILE) { 317 if (exitstatus != 0) 318 break; 319 } else { 320 if (exitstatus == 0) 321 break; 322 } 323 evaltree(n->nbinary.ch2, flags); 324 status = exitstatus; 325 if (evalskip) 326 goto skipping; 327 } 328 loopnest--; 329 exitstatus = status; 330 } 331 332 333 334 static void 335 evalfor(union node *n, int flags) 336 { 337 struct arglist arglist; 338 union node *argp; 339 struct strlist *sp; 340 struct stackmark smark; 341 342 setstackmark(&smark); 343 arglist.lastp = &arglist.list; 344 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 345 oexitstatus = exitstatus; 346 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 347 if (evalskip) 348 goto out; 349 } 350 *arglist.lastp = NULL; 351 352 exitstatus = 0; 353 loopnest++; 354 for (sp = arglist.list ; sp ; sp = sp->next) { 355 setvar(n->nfor.var, sp->text, 0); 356 evaltree(n->nfor.body, flags); 357 if (evalskip) { 358 if (evalskip == SKIPCONT && --skipcount <= 0) { 359 evalskip = 0; 360 continue; 361 } 362 if (evalskip == SKIPBREAK && --skipcount <= 0) 363 evalskip = 0; 364 break; 365 } 366 } 367 loopnest--; 368 out: 369 popstackmark(&smark); 370 } 371 372 373 374 static void 375 evalcase(union node *n, int flags) 376 { 377 union node *cp; 378 union node *patp; 379 struct arglist arglist; 380 struct stackmark smark; 381 382 setstackmark(&smark); 383 arglist.lastp = &arglist.list; 384 oexitstatus = exitstatus; 385 exitstatus = 0; 386 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 387 for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) { 388 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 389 if (casematch(patp, arglist.list->text)) { 390 if (evalskip == 0) { 391 evaltree(cp->nclist.body, flags); 392 } 393 goto out; 394 } 395 } 396 } 397 out: 398 popstackmark(&smark); 399 } 400 401 402 403 /* 404 * Kick off a subshell to evaluate a tree. 405 */ 406 407 static void 408 evalsubshell(union node *n, int flags) 409 { 410 struct job *jp; 411 int backgnd = (n->type == NBACKGND); 412 413 expredir(n->nredir.redirect); 414 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 415 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 416 if (backgnd) 417 flags &=~ EV_TESTED; 418 redirect(n->nredir.redirect, 0); 419 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 420 } else if (!backgnd) { 421 INTOFF; 422 exitstatus = waitforjob(jp, NULL); 423 INTON; 424 } else 425 exitstatus = 0; 426 } 427 428 429 /* 430 * Evaluate a redirected compound command. 431 */ 432 433 static void 434 evalredir(union node *n, int flags) 435 { 436 struct jmploc jmploc; 437 struct jmploc *savehandler; 438 volatile int in_redirect = 1; 439 440 expredir(n->nredir.redirect); 441 savehandler = handler; 442 if (setjmp(jmploc.loc)) { 443 int e; 444 445 handler = savehandler; 446 e = exception; 447 popredir(); 448 if (e == EXERROR || e == EXEXEC) { 449 if (in_redirect) { 450 exitstatus = 2; 451 return; 452 } 453 } 454 longjmp(handler->loc, 1); 455 } else { 456 INTOFF; 457 handler = &jmploc; 458 redirect(n->nredir.redirect, REDIR_PUSH); 459 in_redirect = 0; 460 INTON; 461 evaltree(n->nredir.n, flags); 462 } 463 INTOFF; 464 handler = savehandler; 465 popredir(); 466 INTON; 467 } 468 469 470 /* 471 * Compute the names of the files in a redirection list. 472 */ 473 474 static void 475 expredir(union node *n) 476 { 477 union node *redir; 478 479 for (redir = n ; redir ; redir = redir->nfile.next) { 480 struct arglist fn; 481 fn.lastp = &fn.list; 482 oexitstatus = exitstatus; 483 switch (redir->type) { 484 case NFROM: 485 case NTO: 486 case NFROMTO: 487 case NAPPEND: 488 case NCLOBBER: 489 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 490 redir->nfile.expfname = fn.list->text; 491 break; 492 case NFROMFD: 493 case NTOFD: 494 if (redir->ndup.vname) { 495 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 496 fixredir(redir, fn.list->text, 1); 497 } 498 break; 499 } 500 } 501 } 502 503 504 505 /* 506 * Evaluate a pipeline. All the processes in the pipeline are children 507 * of the process creating the pipeline. (This differs from some versions 508 * of the shell, which make the last process in a pipeline the parent 509 * of all the rest.) 510 */ 511 512 static void 513 evalpipe(union node *n) 514 { 515 struct job *jp; 516 struct nodelist *lp; 517 int pipelen; 518 int prevfd; 519 int pip[2]; 520 521 TRACE(("evalpipe(%p) called\n", (void *)n)); 522 pipelen = 0; 523 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 524 pipelen++; 525 INTOFF; 526 jp = makejob(n, pipelen); 527 prevfd = -1; 528 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 529 prehash(lp->n); 530 pip[1] = -1; 531 if (lp->next) { 532 if (pipe(pip) < 0) { 533 if (prevfd >= 0) 534 close(prevfd); 535 error("Pipe call failed: %s", strerror(errno)); 536 } 537 } 538 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 539 INTON; 540 if (prevfd > 0) { 541 dup2(prevfd, 0); 542 close(prevfd); 543 } 544 if (pip[1] >= 0) { 545 if (!(prevfd >= 0 && pip[0] == 0)) 546 close(pip[0]); 547 if (pip[1] != 1) { 548 dup2(pip[1], 1); 549 close(pip[1]); 550 } 551 } 552 evaltree(lp->n, EV_EXIT); 553 } 554 if (prevfd >= 0) 555 close(prevfd); 556 prevfd = pip[0]; 557 close(pip[1]); 558 } 559 INTON; 560 if (n->npipe.backgnd == 0) { 561 INTOFF; 562 exitstatus = waitforjob(jp, NULL); 563 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 564 INTON; 565 } else 566 exitstatus = 0; 567 } 568 569 570 571 static int 572 is_valid_fast_cmdsubst(union node *n) 573 { 574 union node *argp; 575 576 if (n->type != NCMD) 577 return 0; 578 for (argp = n->ncmd.args ; argp ; argp = argp->narg.next) 579 if (expandhassideeffects(argp->narg.text)) 580 return 0; 581 return 1; 582 } 583 584 /* 585 * Execute a command inside back quotes. If it's a builtin command, we 586 * want to save its output in a block obtained from malloc. Otherwise 587 * we fork off a subprocess and get the output of the command via a pipe. 588 * Should be called with interrupts off. 589 */ 590 591 void 592 evalbackcmd(union node *n, struct backcmd *result) 593 { 594 int pip[2]; 595 struct job *jp; 596 struct stackmark smark; /* unnecessary */ 597 struct jmploc jmploc; 598 struct jmploc *savehandler; 599 600 setstackmark(&smark); 601 result->fd = -1; 602 result->buf = NULL; 603 result->nleft = 0; 604 result->jp = NULL; 605 if (n == NULL) { 606 exitstatus = 0; 607 goto out; 608 } 609 if (is_valid_fast_cmdsubst(n)) { 610 exitstatus = oexitstatus; 611 savehandler = handler; 612 if (setjmp(jmploc.loc)) { 613 if (exception == EXERROR || exception == EXEXEC) 614 exitstatus = 2; 615 else if (exception != 0) { 616 handler = savehandler; 617 longjmp(handler->loc, 1); 618 } 619 } else { 620 handler = &jmploc; 621 evalcommand(n, EV_BACKCMD, result); 622 } 623 handler = savehandler; 624 } else { 625 exitstatus = 0; 626 if (pipe(pip) < 0) 627 error("Pipe call failed: %s", strerror(errno)); 628 jp = makejob(n, 1); 629 if (forkshell(jp, n, FORK_NOJOB) == 0) { 630 FORCEINTON; 631 close(pip[0]); 632 if (pip[1] != 1) { 633 dup2(pip[1], 1); 634 close(pip[1]); 635 } 636 evaltree(n, EV_EXIT); 637 } 638 close(pip[1]); 639 result->fd = pip[0]; 640 result->jp = jp; 641 } 642 out: 643 popstackmark(&smark); 644 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 645 result->fd, result->buf, result->nleft, result->jp)); 646 } 647 648 /* 649 * Check if a builtin can safely be executed in the same process, 650 * even though it should be in a subshell (command substitution). 651 * Note that jobid, jobs, times and trap can show information not 652 * available in a child process; this is deliberate. 653 * The arguments should already have been expanded. 654 */ 655 static int 656 safe_builtin(int idx, int argc, char **argv) 657 { 658 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 659 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 660 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 661 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 662 idx == TYPECMD) 663 return (1); 664 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 665 idx == UMASKCMD) 666 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 667 if (idx == SETCMD) 668 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 669 argv[1][0] == '+') && argv[1][1] == 'o' && 670 argv[1][2] == '\0')); 671 return (0); 672 } 673 674 /* 675 * Execute a simple command. 676 * Note: This may or may not return if (flags & EV_EXIT). 677 */ 678 679 static void 680 evalcommand(union node *cmd, int flgs, struct backcmd *backcmd) 681 { 682 struct stackmark smark; 683 union node *argp; 684 struct arglist arglist; 685 struct arglist varlist; 686 volatile int flags = flgs; 687 char **volatile argv; 688 volatile int argc; 689 char **envp; 690 int varflag; 691 struct strlist *sp; 692 int mode; 693 int pip[2]; 694 struct cmdentry cmdentry; 695 struct job *volatile jp; 696 struct jmploc jmploc; 697 struct jmploc *savehandler; 698 const char *savecmdname; 699 struct shparam saveparam; 700 struct localvar *savelocalvars; 701 struct parsefile *savetopfile; 702 volatile int e; 703 char *volatile lastarg; 704 int realstatus; 705 volatile int do_clearcmdentry; 706 const char *path = pathval(); 707 708 /* First expand the arguments. */ 709 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 710 setstackmark(&smark); 711 arglist.lastp = &arglist.list; 712 varlist.lastp = &varlist.list; 713 varflag = 1; 714 jp = NULL; 715 do_clearcmdentry = 0; 716 oexitstatus = exitstatus; 717 exitstatus = 0; 718 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 719 char *p = argp->narg.text; 720 if (varflag && is_name(*p)) { 721 do { 722 p++; 723 } while (is_in_name(*p)); 724 if (*p == '=') { 725 expandarg(argp, &varlist, EXP_VARTILDE); 726 continue; 727 } 728 } 729 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 730 varflag = 0; 731 } 732 *arglist.lastp = NULL; 733 *varlist.lastp = NULL; 734 expredir(cmd->ncmd.redirect); 735 argc = 0; 736 for (sp = arglist.list ; sp ; sp = sp->next) 737 argc++; 738 /* Add one slot at the beginning for tryexec(). */ 739 argv = stalloc(sizeof (char *) * (argc + 2)); 740 argv++; 741 742 for (sp = arglist.list ; sp ; sp = sp->next) { 743 TRACE(("evalcommand arg: %s\n", sp->text)); 744 *argv++ = sp->text; 745 } 746 *argv = NULL; 747 lastarg = NULL; 748 if (iflag && funcnest == 0 && argc > 0) 749 lastarg = argv[-1]; 750 argv -= argc; 751 752 /* Print the command if xflag is set. */ 753 if (xflag) { 754 char sep = 0; 755 const char *p; 756 out2str(ps4val()); 757 for (sp = varlist.list ; sp ; sp = sp->next) { 758 if (sep != 0) 759 out2c(' '); 760 p = strchr(sp->text, '='); 761 if (p != NULL) { 762 p++; 763 outbin(sp->text, p - sp->text, out2); 764 out2qstr(p); 765 } else 766 out2qstr(sp->text); 767 sep = ' '; 768 } 769 for (sp = arglist.list ; sp ; sp = sp->next) { 770 if (sep != 0) 771 out2c(' '); 772 /* Disambiguate command looking like assignment. */ 773 if (sp == arglist.list && 774 strchr(sp->text, '=') != NULL && 775 strchr(sp->text, '\'') == NULL) { 776 out2c('\''); 777 out2str(sp->text); 778 out2c('\''); 779 } else 780 out2qstr(sp->text); 781 sep = ' '; 782 } 783 out2c('\n'); 784 flushout(&errout); 785 } 786 787 /* Now locate the command. */ 788 if (argc == 0) { 789 /* Variable assignment(s) without command */ 790 cmdentry.cmdtype = CMDBUILTIN; 791 cmdentry.u.index = BLTINCMD; 792 cmdentry.special = 0; 793 } else { 794 static const char PATH[] = "PATH="; 795 int cmd_flags = 0, bltinonly = 0; 796 797 /* 798 * Modify the command lookup path, if a PATH= assignment 799 * is present 800 */ 801 for (sp = varlist.list ; sp ; sp = sp->next) 802 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 803 path = sp->text + sizeof(PATH) - 1; 804 /* 805 * On `PATH=... command`, we need to make 806 * sure that the command isn't using the 807 * non-updated hash table of the outer PATH 808 * setting and we need to make sure that 809 * the hash table isn't filled with items 810 * from the temporary setting. 811 * 812 * It would be better to forbit using and 813 * updating the table while this command 814 * runs, by the command finding mechanism 815 * is heavily integrated with hash handling, 816 * so we just delete the hash before and after 817 * the command runs. Partly deleting like 818 * changepatch() does doesn't seem worth the 819 * bookinging effort, since most such runs add 820 * directories in front of the new PATH. 821 */ 822 clearcmdentry(); 823 do_clearcmdentry = 1; 824 } 825 826 for (;;) { 827 if (bltinonly) { 828 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 829 if (cmdentry.u.index < 0) { 830 cmdentry.u.index = BLTINCMD; 831 argv--; 832 argc++; 833 break; 834 } 835 } else 836 find_command(argv[0], &cmdentry, cmd_flags, path); 837 /* implement the bltin and command builtins here */ 838 if (cmdentry.cmdtype != CMDBUILTIN) 839 break; 840 if (cmdentry.u.index == BLTINCMD) { 841 if (argc == 1) 842 break; 843 argv++; 844 argc--; 845 bltinonly = 1; 846 } else if (cmdentry.u.index == COMMANDCMD) { 847 if (argc == 1) 848 break; 849 if (!strcmp(argv[1], "-p")) { 850 if (argc == 2) 851 break; 852 if (argv[2][0] == '-') { 853 if (strcmp(argv[2], "--")) 854 break; 855 if (argc == 3) 856 break; 857 argv += 3; 858 argc -= 3; 859 } else { 860 argv += 2; 861 argc -= 2; 862 } 863 path = _PATH_STDPATH; 864 clearcmdentry(); 865 do_clearcmdentry = 1; 866 } else if (!strcmp(argv[1], "--")) { 867 if (argc == 2) 868 break; 869 argv += 2; 870 argc -= 2; 871 } else if (argv[1][0] == '-') 872 break; 873 else { 874 argv++; 875 argc--; 876 } 877 cmd_flags |= DO_NOFUNC; 878 bltinonly = 0; 879 } else 880 break; 881 } 882 /* 883 * Special builtins lose their special properties when 884 * called via 'command'. 885 */ 886 if (cmd_flags & DO_NOFUNC) 887 cmdentry.special = 0; 888 } 889 890 /* Fork off a child process if necessary. */ 891 if (cmd->ncmd.backgnd 892 || ((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 893 && ((flags & EV_EXIT) == 0 || have_traps())) 894 || ((flags & EV_BACKCMD) != 0 895 && (cmdentry.cmdtype != CMDBUILTIN || 896 !safe_builtin(cmdentry.u.index, argc, argv)))) { 897 jp = makejob(cmd, 1); 898 mode = cmd->ncmd.backgnd; 899 if (flags & EV_BACKCMD) { 900 mode = FORK_NOJOB; 901 if (pipe(pip) < 0) 902 error("Pipe call failed: %s", strerror(errno)); 903 } 904 if (forkshell(jp, cmd, mode) != 0) 905 goto parent; /* at end of routine */ 906 if (flags & EV_BACKCMD) { 907 FORCEINTON; 908 close(pip[0]); 909 if (pip[1] != 1) { 910 dup2(pip[1], 1); 911 close(pip[1]); 912 } 913 } 914 flags |= EV_EXIT; 915 } 916 917 /* This is the child process if a fork occurred. */ 918 /* Execute the command. */ 919 if (cmdentry.cmdtype == CMDFUNCTION) { 920 #ifdef DEBUG 921 trputs("Shell function: "); trargs(argv); 922 #endif 923 saveparam = shellparam; 924 shellparam.malloc = 0; 925 shellparam.reset = 1; 926 shellparam.nparam = argc - 1; 927 shellparam.p = argv + 1; 928 shellparam.optnext = NULL; 929 INTOFF; 930 savelocalvars = localvars; 931 localvars = NULL; 932 reffunc(cmdentry.u.func); 933 savehandler = handler; 934 if (setjmp(jmploc.loc)) { 935 freeparam(&shellparam); 936 shellparam = saveparam; 937 popredir(); 938 unreffunc(cmdentry.u.func); 939 poplocalvars(); 940 localvars = savelocalvars; 941 funcnest--; 942 handler = savehandler; 943 longjmp(handler->loc, 1); 944 } 945 handler = &jmploc; 946 funcnest++; 947 redirect(cmd->ncmd.redirect, REDIR_PUSH); 948 INTON; 949 for (sp = varlist.list ; sp ; sp = sp->next) 950 mklocal(sp->text); 951 exitstatus = oexitstatus; 952 evaltree(getfuncnode(cmdentry.u.func), 953 flags & (EV_TESTED | EV_EXIT)); 954 INTOFF; 955 unreffunc(cmdentry.u.func); 956 poplocalvars(); 957 localvars = savelocalvars; 958 freeparam(&shellparam); 959 shellparam = saveparam; 960 handler = savehandler; 961 funcnest--; 962 popredir(); 963 INTON; 964 if (evalskip == SKIPFUNC) { 965 evalskip = 0; 966 skipcount = 0; 967 } 968 if (jp) 969 exitshell(exitstatus); 970 } else if (cmdentry.cmdtype == CMDBUILTIN) { 971 #ifdef DEBUG 972 trputs("builtin command: "); trargs(argv); 973 #endif 974 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 975 if (flags == EV_BACKCMD) { 976 memout.nleft = 0; 977 memout.nextc = memout.buf; 978 memout.bufsize = 64; 979 mode |= REDIR_BACKQ; 980 cmdentry.special = 0; 981 } 982 savecmdname = commandname; 983 savetopfile = getcurrentfile(); 984 cmdenviron = varlist.list; 985 e = -1; 986 savehandler = handler; 987 if (setjmp(jmploc.loc)) { 988 e = exception; 989 if (e == EXINT) 990 exitstatus = SIGINT+128; 991 else if (e != EXEXIT) 992 exitstatus = 2; 993 goto cmddone; 994 } 995 handler = &jmploc; 996 redirect(cmd->ncmd.redirect, mode); 997 /* 998 * If there is no command word, redirection errors should 999 * not be fatal but assignment errors should. 1000 */ 1001 if (argc == 0 && !(flags & EV_BACKCMD)) 1002 cmdentry.special = 1; 1003 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1004 if (argc > 0) 1005 bltinsetlocale(); 1006 commandname = argv[0]; 1007 argptr = argv + 1; 1008 nextopt_optptr = NULL; /* initialize nextopt */ 1009 builtin_flags = flags; 1010 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1011 flushall(); 1012 cmddone: 1013 if (argc > 0) 1014 bltinunsetlocale(); 1015 cmdenviron = NULL; 1016 out1 = &output; 1017 out2 = &errout; 1018 freestdout(); 1019 handler = savehandler; 1020 commandname = savecmdname; 1021 if (jp) 1022 exitshell(exitstatus); 1023 if (flags == EV_BACKCMD) { 1024 backcmd->buf = memout.buf; 1025 backcmd->nleft = memout.nextc - memout.buf; 1026 memout.buf = NULL; 1027 } 1028 if (cmdentry.u.index != EXECCMD) 1029 popredir(); 1030 if (e != -1) { 1031 if ((e != EXERROR && e != EXEXEC) 1032 || cmdentry.special) 1033 exraise(e); 1034 popfilesupto(savetopfile); 1035 if (flags != EV_BACKCMD) 1036 FORCEINTON; 1037 } 1038 } else { 1039 #ifdef DEBUG 1040 trputs("normal command: "); trargs(argv); 1041 #endif 1042 redirect(cmd->ncmd.redirect, 0); 1043 for (sp = varlist.list ; sp ; sp = sp->next) 1044 setvareq(sp->text, VEXPORT|VSTACK); 1045 envp = environment(); 1046 shellexec(argv, envp, path, cmdentry.u.index); 1047 /*NOTREACHED*/ 1048 } 1049 goto out; 1050 1051 parent: /* parent process gets here (if we forked) */ 1052 if (mode == FORK_FG) { /* argument to fork */ 1053 INTOFF; 1054 exitstatus = waitforjob(jp, &realstatus); 1055 INTON; 1056 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1057 evalskip = SKIPBREAK; 1058 skipcount = loopnest; 1059 } 1060 } else if (mode == FORK_NOJOB) { 1061 backcmd->fd = pip[0]; 1062 close(pip[1]); 1063 backcmd->jp = jp; 1064 } else 1065 exitstatus = 0; 1066 1067 out: 1068 if (lastarg) 1069 setvar("_", lastarg, 0); 1070 if (do_clearcmdentry) 1071 clearcmdentry(); 1072 popstackmark(&smark); 1073 } 1074 1075 1076 1077 /* 1078 * Search for a command. This is called before we fork so that the 1079 * location of the command will be available in the parent as well as 1080 * the child. The check for "goodname" is an overly conservative 1081 * check that the name will not be subject to expansion. 1082 */ 1083 1084 static void 1085 prehash(union node *n) 1086 { 1087 struct cmdentry entry; 1088 1089 if (n && n->type == NCMD && n->ncmd.args) 1090 if (goodname(n->ncmd.args->narg.text)) 1091 find_command(n->ncmd.args->narg.text, &entry, 0, 1092 pathval()); 1093 } 1094 1095 1096 1097 /* 1098 * Builtin commands. Builtin commands whose functions are closely 1099 * tied to evaluation are implemented here. 1100 */ 1101 1102 /* 1103 * No command given, a bltin command with no arguments, or a bltin command 1104 * with an invalid name. 1105 */ 1106 1107 int 1108 bltincmd(int argc, char **argv) 1109 { 1110 if (argc > 1) { 1111 out2fmt_flush("%s: not found\n", argv[1]); 1112 return 127; 1113 } 1114 /* 1115 * Preserve exitstatus of a previous possible redirection 1116 * as POSIX mandates 1117 */ 1118 return exitstatus; 1119 } 1120 1121 1122 /* 1123 * Handle break and continue commands. Break, continue, and return are 1124 * all handled by setting the evalskip flag. The evaluation routines 1125 * above all check this flag, and if it is set they start skipping 1126 * commands rather than executing them. The variable skipcount is 1127 * the number of loops to break/continue, or the number of function 1128 * levels to return. (The latter is always 1.) It should probably 1129 * be an error to break out of more loops than exist, but it isn't 1130 * in the standard shell so we don't make it one here. 1131 */ 1132 1133 int 1134 breakcmd(int argc, char **argv) 1135 { 1136 int n = argc > 1 ? number(argv[1]) : 1; 1137 1138 if (n > loopnest) 1139 n = loopnest; 1140 if (n > 0) { 1141 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1142 skipcount = n; 1143 } 1144 return 0; 1145 } 1146 1147 /* 1148 * The `command' command. 1149 */ 1150 int 1151 commandcmd(int argc, char **argv) 1152 { 1153 const char *path; 1154 int ch; 1155 int cmd = -1; 1156 1157 path = bltinlookup("PATH", 1); 1158 1159 optind = optreset = 1; 1160 opterr = 0; 1161 while ((ch = getopt(argc, argv, "pvV")) != -1) { 1162 switch (ch) { 1163 case 'p': 1164 path = _PATH_STDPATH; 1165 break; 1166 case 'v': 1167 cmd = TYPECMD_SMALLV; 1168 break; 1169 case 'V': 1170 cmd = TYPECMD_BIGV; 1171 break; 1172 case '?': 1173 default: 1174 error("unknown option: -%c", optopt); 1175 } 1176 } 1177 argc -= optind; 1178 argv += optind; 1179 1180 if (cmd != -1) { 1181 if (argc != 1) 1182 error("wrong number of arguments"); 1183 return typecmd_impl(2, argv - 1, cmd, path); 1184 } 1185 if (argc != 0) 1186 error("commandcmd bad call"); 1187 1188 /* 1189 * Do nothing successfully if no command was specified; 1190 * ksh also does this. 1191 */ 1192 return(0); 1193 } 1194 1195 1196 /* 1197 * The return command. 1198 */ 1199 1200 int 1201 returncmd(int argc, char **argv) 1202 { 1203 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1204 1205 if (funcnest) { 1206 evalskip = SKIPFUNC; 1207 skipcount = 1; 1208 } else { 1209 /* skip the rest of the file */ 1210 evalskip = SKIPFILE; 1211 skipcount = 1; 1212 } 1213 return ret; 1214 } 1215 1216 1217 int 1218 falsecmd(int argc __unused, char **argv __unused) 1219 { 1220 return 1; 1221 } 1222 1223 1224 int 1225 truecmd(int argc __unused, char **argv __unused) 1226 { 1227 return 0; 1228 } 1229 1230 1231 int 1232 execcmd(int argc, char **argv) 1233 { 1234 /* 1235 * Because we have historically not supported any options, 1236 * only treat "--" specially. 1237 */ 1238 if (argc > 1 && strcmp(argv[1], "--") == 0) 1239 argc--, argv++; 1240 if (argc > 1) { 1241 struct strlist *sp; 1242 1243 iflag = 0; /* exit on error */ 1244 mflag = 0; 1245 optschanged(); 1246 for (sp = cmdenviron; sp ; sp = sp->next) 1247 setvareq(sp->text, VEXPORT|VSTACK); 1248 shellexec(argv + 1, environment(), pathval(), 0); 1249 1250 } 1251 return 0; 1252 } 1253 1254 1255 int 1256 timescmd(int argc __unused, char **argv __unused) 1257 { 1258 struct rusage ru; 1259 long shumins, shsmins, chumins, chsmins; 1260 double shusecs, shssecs, chusecs, chssecs; 1261 1262 if (getrusage(RUSAGE_SELF, &ru) < 0) 1263 return 1; 1264 shumins = ru.ru_utime.tv_sec / 60; 1265 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1266 shsmins = ru.ru_stime.tv_sec / 60; 1267 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1268 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1269 return 1; 1270 chumins = ru.ru_utime.tv_sec / 60; 1271 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1272 chsmins = ru.ru_stime.tv_sec / 60; 1273 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1274 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1275 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1276 return 0; 1277 } 1278