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 1.108 2011/06/09 23:12:23 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 && !nflag) { 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 oexitstatus = exitstatus; 414 expredir(n->nredir.redirect); 415 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 416 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 417 if (backgnd) 418 flags &=~ EV_TESTED; 419 redirect(n->nredir.redirect, 0); 420 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 421 } else if (!backgnd) { 422 INTOFF; 423 exitstatus = waitforjob(jp, NULL); 424 INTON; 425 } else 426 exitstatus = 0; 427 } 428 429 430 /* 431 * Evaluate a redirected compound command. 432 */ 433 434 static void 435 evalredir(union node *n, int flags) 436 { 437 struct jmploc jmploc; 438 struct jmploc *savehandler; 439 volatile int in_redirect = 1; 440 441 oexitstatus = exitstatus; 442 expredir(n->nredir.redirect); 443 savehandler = handler; 444 if (setjmp(jmploc.loc)) { 445 int e; 446 447 handler = savehandler; 448 e = exception; 449 popredir(); 450 if (e == EXERROR || e == EXEXEC) { 451 if (in_redirect) { 452 exitstatus = 2; 453 return; 454 } 455 } 456 longjmp(handler->loc, 1); 457 } else { 458 INTOFF; 459 handler = &jmploc; 460 redirect(n->nredir.redirect, REDIR_PUSH); 461 in_redirect = 0; 462 INTON; 463 evaltree(n->nredir.n, flags); 464 } 465 INTOFF; 466 handler = savehandler; 467 popredir(); 468 INTON; 469 } 470 471 472 /* 473 * Compute the names of the files in a redirection list. 474 */ 475 476 static void 477 expredir(union node *n) 478 { 479 union node *redir; 480 481 for (redir = n ; redir ; redir = redir->nfile.next) { 482 struct arglist fn; 483 fn.lastp = &fn.list; 484 switch (redir->type) { 485 case NFROM: 486 case NTO: 487 case NFROMTO: 488 case NAPPEND: 489 case NCLOBBER: 490 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 491 redir->nfile.expfname = fn.list->text; 492 break; 493 case NFROMFD: 494 case NTOFD: 495 if (redir->ndup.vname) { 496 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 497 fixredir(redir, fn.list->text, 1); 498 } 499 break; 500 } 501 } 502 } 503 504 505 506 /* 507 * Evaluate a pipeline. All the processes in the pipeline are children 508 * of the process creating the pipeline. (This differs from some versions 509 * of the shell, which make the last process in a pipeline the parent 510 * of all the rest.) 511 */ 512 513 static void 514 evalpipe(union node *n) 515 { 516 struct job *jp; 517 struct nodelist *lp; 518 int pipelen; 519 int prevfd; 520 int pip[2]; 521 522 TRACE(("evalpipe(%p) called\n", (void *)n)); 523 pipelen = 0; 524 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 525 pipelen++; 526 INTOFF; 527 jp = makejob(n, pipelen); 528 prevfd = -1; 529 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 530 prehash(lp->n); 531 pip[1] = -1; 532 if (lp->next) { 533 if (pipe(pip) < 0) { 534 if (prevfd >= 0) 535 close(prevfd); 536 error("Pipe call failed: %s", strerror(errno)); 537 } 538 } 539 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 540 INTON; 541 if (prevfd > 0) { 542 dup2(prevfd, 0); 543 close(prevfd); 544 } 545 if (pip[1] >= 0) { 546 if (!(prevfd >= 0 && pip[0] == 0)) 547 close(pip[0]); 548 if (pip[1] != 1) { 549 dup2(pip[1], 1); 550 close(pip[1]); 551 } 552 } 553 evaltree(lp->n, EV_EXIT); 554 } 555 if (prevfd >= 0) 556 close(prevfd); 557 prevfd = pip[0]; 558 if (pip[1] != -1) 559 close(pip[1]); 560 } 561 INTON; 562 if (n->npipe.backgnd == 0) { 563 INTOFF; 564 exitstatus = waitforjob(jp, NULL); 565 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 566 INTON; 567 } else 568 exitstatus = 0; 569 } 570 571 572 573 static int 574 is_valid_fast_cmdsubst(union node *n) 575 { 576 union node *argp; 577 578 if (n->type != NCMD) 579 return 0; 580 for (argp = n->ncmd.args ; argp ; argp = argp->narg.next) 581 if (expandhassideeffects(argp->narg.text)) 582 return 0; 583 return 1; 584 } 585 586 /* 587 * Execute a command inside back quotes. If it's a builtin command, we 588 * want to save its output in a block obtained from malloc. Otherwise 589 * we fork off a subprocess and get the output of the command via a pipe. 590 * Should be called with interrupts off. 591 */ 592 593 void 594 evalbackcmd(union node *n, struct backcmd *result) 595 { 596 int pip[2]; 597 struct job *jp; 598 struct stackmark smark; /* unnecessary */ 599 struct jmploc jmploc; 600 struct jmploc *savehandler; 601 602 setstackmark(&smark); 603 result->fd = -1; 604 result->buf = NULL; 605 result->nleft = 0; 606 result->jp = NULL; 607 if (n == NULL) { 608 exitstatus = 0; 609 goto out; 610 } 611 if (is_valid_fast_cmdsubst(n)) { 612 exitstatus = oexitstatus; 613 savehandler = handler; 614 if (setjmp(jmploc.loc)) { 615 if (exception == EXERROR || exception == EXEXEC) 616 exitstatus = 2; 617 else if (exception != 0) { 618 handler = savehandler; 619 longjmp(handler->loc, 1); 620 } 621 } else { 622 handler = &jmploc; 623 evalcommand(n, EV_BACKCMD, result); 624 } 625 handler = savehandler; 626 } else { 627 exitstatus = 0; 628 if (pipe(pip) < 0) 629 error("Pipe call failed: %s", strerror(errno)); 630 jp = makejob(n, 1); 631 if (forkshell(jp, n, FORK_NOJOB) == 0) { 632 FORCEINTON; 633 close(pip[0]); 634 if (pip[1] != 1) { 635 dup2(pip[1], 1); 636 close(pip[1]); 637 } 638 evaltree(n, EV_EXIT); 639 } 640 close(pip[1]); 641 result->fd = pip[0]; 642 result->jp = jp; 643 } 644 out: 645 popstackmark(&smark); 646 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 647 result->fd, result->buf, result->nleft, result->jp)); 648 } 649 650 /* 651 * Check if a builtin can safely be executed in the same process, 652 * even though it should be in a subshell (command substitution). 653 * Note that jobid, jobs, times and trap can show information not 654 * available in a child process; this is deliberate. 655 * The arguments should already have been expanded. 656 */ 657 static int 658 safe_builtin(int idx, int argc, char **argv) 659 { 660 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 661 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 662 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 663 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 664 idx == TYPECMD) 665 return (1); 666 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 667 idx == UMASKCMD) 668 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 669 if (idx == SETCMD) 670 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 671 argv[1][0] == '+') && argv[1][1] == 'o' && 672 argv[1][2] == '\0')); 673 return (0); 674 } 675 676 /* 677 * Execute a simple command. 678 * Note: This may or may not return if (flags & EV_EXIT). 679 */ 680 681 static void 682 evalcommand(union node *cmd, int flgs, struct backcmd *backcmd) 683 { 684 struct stackmark smark; 685 union node *argp; 686 struct arglist arglist; 687 struct arglist varlist; 688 volatile int flags = flgs; 689 char **volatile argv; 690 volatile int argc; 691 char **envp; 692 int varflag; 693 struct strlist *sp; 694 int mode; 695 int pip[2]; 696 struct cmdentry cmdentry; 697 struct job *volatile jp; 698 struct jmploc jmploc; 699 struct jmploc *savehandler; 700 const char *savecmdname; 701 struct shparam saveparam; 702 struct localvar *savelocalvars; 703 struct parsefile *savetopfile; 704 volatile int e; 705 char *volatile lastarg; 706 int realstatus; 707 volatile int do_clearcmdentry; 708 const char *path = pathval(); 709 710 /* First expand the arguments. */ 711 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 712 setstackmark(&smark); 713 arglist.lastp = &arglist.list; 714 varlist.lastp = &varlist.list; 715 varflag = 1; 716 jp = NULL; 717 do_clearcmdentry = 0; 718 oexitstatus = exitstatus; 719 exitstatus = 0; 720 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 721 if (varflag && isassignment(argp->narg.text)) { 722 expandarg(argp, &varlist, EXP_VARTILDE); 723 continue; 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, *ps4; 752 ps4 = expandstr(ps4val()); 753 out2str(ps4 != NULL ? ps4 : ps4val()); 754 for (sp = varlist.list ; sp ; sp = sp->next) { 755 if (sep != 0) 756 out2c(' '); 757 p = strchr(sp->text, '='); 758 if (p != NULL) { 759 p++; 760 outbin(sp->text, p - sp->text, out2); 761 out2qstr(p); 762 } else 763 out2qstr(sp->text); 764 sep = ' '; 765 } 766 for (sp = arglist.list ; sp ; sp = sp->next) { 767 if (sep != 0) 768 out2c(' '); 769 /* Disambiguate command looking like assignment. */ 770 if (sp == arglist.list && 771 strchr(sp->text, '=') != NULL && 772 strchr(sp->text, '\'') == NULL) { 773 out2c('\''); 774 out2str(sp->text); 775 out2c('\''); 776 } else 777 out2qstr(sp->text); 778 sep = ' '; 779 } 780 out2c('\n'); 781 flushout(&errout); 782 } 783 784 /* Now locate the command. */ 785 if (argc == 0) { 786 /* Variable assignment(s) without command */ 787 cmdentry.cmdtype = CMDBUILTIN; 788 cmdentry.u.index = BLTINCMD; 789 cmdentry.special = 0; 790 } else { 791 static const char PATH[] = "PATH="; 792 int cmd_flags = 0, bltinonly = 0; 793 794 /* 795 * Modify the command lookup path, if a PATH= assignment 796 * is present 797 */ 798 for (sp = varlist.list ; sp ; sp = sp->next) 799 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 800 path = sp->text + sizeof(PATH) - 1; 801 /* 802 * On `PATH=... command`, we need to make 803 * sure that the command isn't using the 804 * non-updated hash table of the outer PATH 805 * setting and we need to make sure that 806 * the hash table isn't filled with items 807 * from the temporary setting. 808 * 809 * It would be better to forbit using and 810 * updating the table while this command 811 * runs, by the command finding mechanism 812 * is heavily integrated with hash handling, 813 * so we just delete the hash before and after 814 * the command runs. Partly deleting like 815 * changepatch() does doesn't seem worth the 816 * bookinging effort, since most such runs add 817 * directories in front of the new PATH. 818 */ 819 clearcmdentry(); 820 do_clearcmdentry = 1; 821 } 822 823 for (;;) { 824 if (bltinonly) { 825 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 826 if (cmdentry.u.index < 0) { 827 cmdentry.u.index = BLTINCMD; 828 argv--; 829 argc++; 830 break; 831 } 832 } else 833 find_command(argv[0], &cmdentry, cmd_flags, path); 834 /* implement the bltin and command builtins here */ 835 if (cmdentry.cmdtype != CMDBUILTIN) 836 break; 837 if (cmdentry.u.index == BLTINCMD) { 838 if (argc == 1) 839 break; 840 argv++; 841 argc--; 842 bltinonly = 1; 843 } else if (cmdentry.u.index == COMMANDCMD) { 844 if (argc == 1) 845 break; 846 if (!strcmp(argv[1], "-p")) { 847 if (argc == 2) 848 break; 849 if (argv[2][0] == '-') { 850 if (strcmp(argv[2], "--")) 851 break; 852 if (argc == 3) 853 break; 854 argv += 3; 855 argc -= 3; 856 } else { 857 argv += 2; 858 argc -= 2; 859 } 860 path = _PATH_STDPATH; 861 clearcmdentry(); 862 do_clearcmdentry = 1; 863 } else if (!strcmp(argv[1], "--")) { 864 if (argc == 2) 865 break; 866 argv += 2; 867 argc -= 2; 868 } else if (argv[1][0] == '-') 869 break; 870 else { 871 argv++; 872 argc--; 873 } 874 cmd_flags |= DO_NOFUNC; 875 bltinonly = 0; 876 } else 877 break; 878 } 879 /* 880 * Special builtins lose their special properties when 881 * called via 'command'. 882 */ 883 if (cmd_flags & DO_NOFUNC) 884 cmdentry.special = 0; 885 } 886 887 /* Fork off a child process if necessary. */ 888 if (cmd->ncmd.backgnd 889 || ((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 890 && ((flags & EV_EXIT) == 0 || have_traps())) 891 || ((flags & EV_BACKCMD) != 0 892 && (cmdentry.cmdtype != CMDBUILTIN || 893 !safe_builtin(cmdentry.u.index, argc, argv)))) { 894 jp = makejob(cmd, 1); 895 mode = cmd->ncmd.backgnd; 896 if (flags & EV_BACKCMD) { 897 mode = FORK_NOJOB; 898 if (pipe(pip) < 0) 899 error("Pipe call failed: %s", strerror(errno)); 900 } 901 if (forkshell(jp, cmd, mode) != 0) 902 goto parent; /* at end of routine */ 903 if (flags & EV_BACKCMD) { 904 FORCEINTON; 905 close(pip[0]); 906 if (pip[1] != 1) { 907 dup2(pip[1], 1); 908 close(pip[1]); 909 } 910 } 911 flags |= EV_EXIT; 912 } 913 914 /* This is the child process if a fork occurred. */ 915 /* Execute the command. */ 916 if (cmdentry.cmdtype == CMDFUNCTION) { 917 #ifdef DEBUG 918 trputs("Shell function: "); trargs(argv); 919 #endif 920 saveparam = shellparam; 921 shellparam.malloc = 0; 922 shellparam.reset = 1; 923 shellparam.nparam = argc - 1; 924 shellparam.p = argv + 1; 925 shellparam.optnext = NULL; 926 INTOFF; 927 savelocalvars = localvars; 928 localvars = NULL; 929 reffunc(cmdentry.u.func); 930 savehandler = handler; 931 if (setjmp(jmploc.loc)) { 932 freeparam(&shellparam); 933 shellparam = saveparam; 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 evaltree(getfuncnode(cmdentry.u.func), 950 flags & (EV_TESTED | EV_EXIT)); 951 INTOFF; 952 unreffunc(cmdentry.u.func); 953 poplocalvars(); 954 localvars = savelocalvars; 955 freeparam(&shellparam); 956 shellparam = saveparam; 957 handler = savehandler; 958 funcnest--; 959 popredir(); 960 INTON; 961 if (evalskip == SKIPFUNC) { 962 evalskip = 0; 963 skipcount = 0; 964 } 965 if (jp) 966 exitshell(exitstatus); 967 } else if (cmdentry.cmdtype == CMDBUILTIN) { 968 #ifdef DEBUG 969 trputs("builtin command: "); trargs(argv); 970 #endif 971 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 972 if (flags == EV_BACKCMD) { 973 memout.nleft = 0; 974 memout.nextc = memout.buf; 975 memout.bufsize = 64; 976 mode |= REDIR_BACKQ; 977 cmdentry.special = 0; 978 } 979 savecmdname = commandname; 980 savetopfile = getcurrentfile(); 981 cmdenviron = varlist.list; 982 e = -1; 983 savehandler = handler; 984 if (setjmp(jmploc.loc)) { 985 e = exception; 986 if (e == EXINT) 987 exitstatus = SIGINT+128; 988 else if (e != EXEXIT) 989 exitstatus = 2; 990 goto cmddone; 991 } 992 handler = &jmploc; 993 redirect(cmd->ncmd.redirect, mode); 994 /* 995 * If there is no command word, redirection errors should 996 * not be fatal but assignment errors should. 997 */ 998 if (argc == 0 && !(flags & EV_BACKCMD)) 999 cmdentry.special = 1; 1000 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1001 if (argc > 0) 1002 bltinsetlocale(); 1003 commandname = argv[0]; 1004 argptr = argv + 1; 1005 nextopt_optptr = NULL; /* initialize nextopt */ 1006 builtin_flags = flags; 1007 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1008 flushall(); 1009 cmddone: 1010 if (argc > 0) 1011 bltinunsetlocale(); 1012 cmdenviron = NULL; 1013 out1 = &output; 1014 out2 = &errout; 1015 freestdout(); 1016 handler = savehandler; 1017 commandname = savecmdname; 1018 if (jp) 1019 exitshell(exitstatus); 1020 if (flags == EV_BACKCMD) { 1021 backcmd->buf = memout.buf; 1022 backcmd->nleft = memout.nextc - memout.buf; 1023 memout.buf = NULL; 1024 } 1025 if (cmdentry.u.index != EXECCMD) 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 } else 1062 exitstatus = 0; 1063 1064 out: 1065 if (lastarg) 1066 setvar("_", lastarg, 0); 1067 if (do_clearcmdentry) 1068 clearcmdentry(); 1069 popstackmark(&smark); 1070 } 1071 1072 1073 1074 /* 1075 * Search for a command. This is called before we fork so that the 1076 * location of the command will be available in the parent as well as 1077 * the child. The check for "goodname" is an overly conservative 1078 * check that the name will not be subject to expansion. 1079 */ 1080 1081 static void 1082 prehash(union node *n) 1083 { 1084 struct cmdentry entry; 1085 1086 if (n && n->type == NCMD && n->ncmd.args) 1087 if (goodname(n->ncmd.args->narg.text)) 1088 find_command(n->ncmd.args->narg.text, &entry, 0, 1089 pathval()); 1090 } 1091 1092 1093 1094 /* 1095 * Builtin commands. Builtin commands whose functions are closely 1096 * tied to evaluation are implemented here. 1097 */ 1098 1099 /* 1100 * No command given, a bltin command with no arguments, or a bltin command 1101 * with an invalid name. 1102 */ 1103 1104 int 1105 bltincmd(int argc, char **argv) 1106 { 1107 if (argc > 1) { 1108 out2fmt_flush("%s: not found\n", argv[1]); 1109 return 127; 1110 } 1111 /* 1112 * Preserve exitstatus of a previous possible redirection 1113 * as POSIX mandates 1114 */ 1115 return exitstatus; 1116 } 1117 1118 1119 /* 1120 * Handle break and continue commands. Break, continue, and return are 1121 * all handled by setting the evalskip flag. The evaluation routines 1122 * above all check this flag, and if it is set they start skipping 1123 * commands rather than executing them. The variable skipcount is 1124 * the number of loops to break/continue, or the number of function 1125 * levels to return. (The latter is always 1.) It should probably 1126 * be an error to break out of more loops than exist, but it isn't 1127 * in the standard shell so we don't make it one here. 1128 */ 1129 1130 int 1131 breakcmd(int argc, char **argv) 1132 { 1133 int n = argc > 1 ? number(argv[1]) : 1; 1134 1135 if (n > loopnest) 1136 n = loopnest; 1137 if (n > 0) { 1138 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1139 skipcount = n; 1140 } 1141 return 0; 1142 } 1143 1144 /* 1145 * The `command' command. 1146 */ 1147 int 1148 commandcmd(int argc, char **argv) 1149 { 1150 const char *path; 1151 int ch; 1152 int cmd = -1; 1153 1154 path = bltinlookup("PATH", 1); 1155 1156 optind = optreset = 1; 1157 opterr = 0; 1158 while ((ch = getopt(argc, argv, "pvV")) != -1) { 1159 switch (ch) { 1160 case 'p': 1161 path = _PATH_STDPATH; 1162 break; 1163 case 'v': 1164 cmd = TYPECMD_SMALLV; 1165 break; 1166 case 'V': 1167 cmd = TYPECMD_BIGV; 1168 break; 1169 case '?': 1170 default: 1171 error("unknown option: -%c", optopt); 1172 } 1173 } 1174 argc -= optind; 1175 argv += optind; 1176 1177 if (cmd != -1) { 1178 if (argc != 1) 1179 error("wrong number of arguments"); 1180 return typecmd_impl(2, argv - 1, cmd, path); 1181 } 1182 if (argc != 0) 1183 error("commandcmd bad call"); 1184 1185 /* 1186 * Do nothing successfully if no command was specified; 1187 * ksh also does this. 1188 */ 1189 return(0); 1190 } 1191 1192 1193 /* 1194 * The return command. 1195 */ 1196 1197 int 1198 returncmd(int argc, char **argv) 1199 { 1200 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1201 1202 if (funcnest) { 1203 evalskip = SKIPFUNC; 1204 skipcount = 1; 1205 } else { 1206 /* skip the rest of the file */ 1207 evalskip = SKIPFILE; 1208 skipcount = 1; 1209 } 1210 return ret; 1211 } 1212 1213 1214 int 1215 falsecmd(int argc __unused, char **argv __unused) 1216 { 1217 return 1; 1218 } 1219 1220 1221 int 1222 truecmd(int argc __unused, char **argv __unused) 1223 { 1224 return 0; 1225 } 1226 1227 1228 int 1229 execcmd(int argc, char **argv) 1230 { 1231 /* 1232 * Because we have historically not supported any options, 1233 * only treat "--" specially. 1234 */ 1235 if (argc > 1 && strcmp(argv[1], "--") == 0) 1236 argc--, argv++; 1237 if (argc > 1) { 1238 struct strlist *sp; 1239 1240 iflag = 0; /* exit on error */ 1241 mflag = 0; 1242 optschanged(); 1243 for (sp = cmdenviron; sp ; sp = sp->next) 1244 setvareq(sp->text, VEXPORT|VSTACK); 1245 shellexec(argv + 1, environment(), pathval(), 0); 1246 1247 } 1248 return 0; 1249 } 1250 1251 1252 int 1253 timescmd(int argc __unused, char **argv __unused) 1254 { 1255 struct rusage ru; 1256 long shumins, shsmins, chumins, chsmins; 1257 double shusecs, shssecs, chusecs, chssecs; 1258 1259 if (getrusage(RUSAGE_SELF, &ru) < 0) 1260 return 1; 1261 shumins = ru.ru_utime.tv_sec / 60; 1262 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1263 shsmins = ru.ru_stime.tv_sec / 60; 1264 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1265 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1266 return 1; 1267 chumins = ru.ru_utime.tv_sec / 60; 1268 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1269 chsmins = ru.ru_stime.tv_sec / 60; 1270 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1271 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1272 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1273 return 0; 1274 } 1275