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 1.105 2011/05/21 22:03:06 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 if (pip[1] != -1) 558 close(pip[1]); 559 } 560 INTON; 561 if (n->npipe.backgnd == 0) { 562 INTOFF; 563 exitstatus = waitforjob(jp, NULL); 564 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 565 INTON; 566 } else 567 exitstatus = 0; 568 } 569 570 571 572 static int 573 is_valid_fast_cmdsubst(union node *n) 574 { 575 union node *argp; 576 577 if (n->type != NCMD) 578 return 0; 579 for (argp = n->ncmd.args ; argp ; argp = argp->narg.next) 580 if (expandhassideeffects(argp->narg.text)) 581 return 0; 582 return 1; 583 } 584 585 /* 586 * Execute a command inside back quotes. If it's a builtin command, we 587 * want to save its output in a block obtained from malloc. Otherwise 588 * we fork off a subprocess and get the output of the command via a pipe. 589 * Should be called with interrupts off. 590 */ 591 592 void 593 evalbackcmd(union node *n, struct backcmd *result) 594 { 595 int pip[2]; 596 struct job *jp; 597 struct stackmark smark; /* unnecessary */ 598 struct jmploc jmploc; 599 struct jmploc *savehandler; 600 601 setstackmark(&smark); 602 result->fd = -1; 603 result->buf = NULL; 604 result->nleft = 0; 605 result->jp = NULL; 606 if (n == NULL) { 607 exitstatus = 0; 608 goto out; 609 } 610 if (is_valid_fast_cmdsubst(n)) { 611 exitstatus = oexitstatus; 612 savehandler = handler; 613 if (setjmp(jmploc.loc)) { 614 if (exception == EXERROR || exception == EXEXEC) 615 exitstatus = 2; 616 else if (exception != 0) { 617 handler = savehandler; 618 longjmp(handler->loc, 1); 619 } 620 } else { 621 handler = &jmploc; 622 evalcommand(n, EV_BACKCMD, result); 623 } 624 handler = savehandler; 625 } else { 626 exitstatus = 0; 627 if (pipe(pip) < 0) 628 error("Pipe call failed: %s", strerror(errno)); 629 jp = makejob(n, 1); 630 if (forkshell(jp, n, FORK_NOJOB) == 0) { 631 FORCEINTON; 632 close(pip[0]); 633 if (pip[1] != 1) { 634 dup2(pip[1], 1); 635 close(pip[1]); 636 } 637 evaltree(n, EV_EXIT); 638 } 639 close(pip[1]); 640 result->fd = pip[0]; 641 result->jp = jp; 642 } 643 out: 644 popstackmark(&smark); 645 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 646 result->fd, result->buf, result->nleft, result->jp)); 647 } 648 649 /* 650 * Check if a builtin can safely be executed in the same process, 651 * even though it should be in a subshell (command substitution). 652 * Note that jobid, jobs, times and trap can show information not 653 * available in a child process; this is deliberate. 654 * The arguments should already have been expanded. 655 */ 656 static int 657 safe_builtin(int idx, int argc, char **argv) 658 { 659 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 660 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 661 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 662 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 663 idx == TYPECMD) 664 return (1); 665 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 666 idx == UMASKCMD) 667 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 668 if (idx == SETCMD) 669 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 670 argv[1][0] == '+') && argv[1][1] == 'o' && 671 argv[1][2] == '\0')); 672 return (0); 673 } 674 675 /* 676 * Execute a simple command. 677 * Note: This may or may not return if (flags & EV_EXIT). 678 */ 679 680 static void 681 evalcommand(union node *cmd, int flgs, struct backcmd *backcmd) 682 { 683 struct stackmark smark; 684 union node *argp; 685 struct arglist arglist; 686 struct arglist varlist; 687 volatile int flags = flgs; 688 char **volatile argv; 689 volatile int argc; 690 char **envp; 691 int varflag; 692 struct strlist *sp; 693 int mode; 694 int pip[2]; 695 struct cmdentry cmdentry; 696 struct job *volatile jp; 697 struct jmploc jmploc; 698 struct jmploc *savehandler; 699 const char *savecmdname; 700 struct shparam saveparam; 701 struct localvar *savelocalvars; 702 struct parsefile *savetopfile; 703 volatile int e; 704 char *volatile lastarg; 705 int realstatus; 706 volatile int do_clearcmdentry; 707 const char *path = pathval(); 708 709 /* First expand the arguments. */ 710 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 711 setstackmark(&smark); 712 arglist.lastp = &arglist.list; 713 varlist.lastp = &varlist.list; 714 varflag = 1; 715 jp = NULL; 716 do_clearcmdentry = 0; 717 oexitstatus = exitstatus; 718 exitstatus = 0; 719 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 720 if (varflag && isassignment(argp->narg.text)) { 721 expandarg(argp, &varlist, EXP_VARTILDE); 722 continue; 723 } 724 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 725 varflag = 0; 726 } 727 *arglist.lastp = NULL; 728 *varlist.lastp = NULL; 729 expredir(cmd->ncmd.redirect); 730 argc = 0; 731 for (sp = arglist.list ; sp ; sp = sp->next) 732 argc++; 733 /* Add one slot at the beginning for tryexec(). */ 734 argv = stalloc(sizeof (char *) * (argc + 2)); 735 argv++; 736 737 for (sp = arglist.list ; sp ; sp = sp->next) { 738 TRACE(("evalcommand arg: %s\n", sp->text)); 739 *argv++ = sp->text; 740 } 741 *argv = NULL; 742 lastarg = NULL; 743 if (iflag && funcnest == 0 && argc > 0) 744 lastarg = argv[-1]; 745 argv -= argc; 746 747 /* Print the command if xflag is set. */ 748 if (xflag) { 749 char sep = 0; 750 const char *p; 751 out2str(ps4val()); 752 for (sp = varlist.list ; sp ; sp = sp->next) { 753 if (sep != 0) 754 out2c(' '); 755 p = strchr(sp->text, '='); 756 if (p != NULL) { 757 p++; 758 outbin(sp->text, p - sp->text, out2); 759 out2qstr(p); 760 } else 761 out2qstr(sp->text); 762 sep = ' '; 763 } 764 for (sp = arglist.list ; sp ; sp = sp->next) { 765 if (sep != 0) 766 out2c(' '); 767 /* Disambiguate command looking like assignment. */ 768 if (sp == arglist.list && 769 strchr(sp->text, '=') != NULL && 770 strchr(sp->text, '\'') == NULL) { 771 out2c('\''); 772 out2str(sp->text); 773 out2c('\''); 774 } else 775 out2qstr(sp->text); 776 sep = ' '; 777 } 778 out2c('\n'); 779 flushout(&errout); 780 } 781 782 /* Now locate the command. */ 783 if (argc == 0) { 784 /* Variable assignment(s) without command */ 785 cmdentry.cmdtype = CMDBUILTIN; 786 cmdentry.u.index = BLTINCMD; 787 cmdentry.special = 0; 788 } else { 789 static const char PATH[] = "PATH="; 790 int cmd_flags = 0, bltinonly = 0; 791 792 /* 793 * Modify the command lookup path, if a PATH= assignment 794 * is present 795 */ 796 for (sp = varlist.list ; sp ; sp = sp->next) 797 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 798 path = sp->text + sizeof(PATH) - 1; 799 /* 800 * On `PATH=... command`, we need to make 801 * sure that the command isn't using the 802 * non-updated hash table of the outer PATH 803 * setting and we need to make sure that 804 * the hash table isn't filled with items 805 * from the temporary setting. 806 * 807 * It would be better to forbit using and 808 * updating the table while this command 809 * runs, by the command finding mechanism 810 * is heavily integrated with hash handling, 811 * so we just delete the hash before and after 812 * the command runs. Partly deleting like 813 * changepatch() does doesn't seem worth the 814 * bookinging effort, since most such runs add 815 * directories in front of the new PATH. 816 */ 817 clearcmdentry(); 818 do_clearcmdentry = 1; 819 } 820 821 for (;;) { 822 if (bltinonly) { 823 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 824 if (cmdentry.u.index < 0) { 825 cmdentry.u.index = BLTINCMD; 826 argv--; 827 argc++; 828 break; 829 } 830 } else 831 find_command(argv[0], &cmdentry, cmd_flags, path); 832 /* implement the bltin and command builtins here */ 833 if (cmdentry.cmdtype != CMDBUILTIN) 834 break; 835 if (cmdentry.u.index == BLTINCMD) { 836 if (argc == 1) 837 break; 838 argv++; 839 argc--; 840 bltinonly = 1; 841 } else if (cmdentry.u.index == COMMANDCMD) { 842 if (argc == 1) 843 break; 844 if (!strcmp(argv[1], "-p")) { 845 if (argc == 2) 846 break; 847 if (argv[2][0] == '-') { 848 if (strcmp(argv[2], "--")) 849 break; 850 if (argc == 3) 851 break; 852 argv += 3; 853 argc -= 3; 854 } else { 855 argv += 2; 856 argc -= 2; 857 } 858 path = _PATH_STDPATH; 859 clearcmdentry(); 860 do_clearcmdentry = 1; 861 } else if (!strcmp(argv[1], "--")) { 862 if (argc == 2) 863 break; 864 argv += 2; 865 argc -= 2; 866 } else if (argv[1][0] == '-') 867 break; 868 else { 869 argv++; 870 argc--; 871 } 872 cmd_flags |= DO_NOFUNC; 873 bltinonly = 0; 874 } else 875 break; 876 } 877 /* 878 * Special builtins lose their special properties when 879 * called via 'command'. 880 */ 881 if (cmd_flags & DO_NOFUNC) 882 cmdentry.special = 0; 883 } 884 885 /* Fork off a child process if necessary. */ 886 if (cmd->ncmd.backgnd 887 || ((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 888 && ((flags & EV_EXIT) == 0 || have_traps())) 889 || ((flags & EV_BACKCMD) != 0 890 && (cmdentry.cmdtype != CMDBUILTIN || 891 !safe_builtin(cmdentry.u.index, argc, argv)))) { 892 jp = makejob(cmd, 1); 893 mode = cmd->ncmd.backgnd; 894 if (flags & EV_BACKCMD) { 895 mode = FORK_NOJOB; 896 if (pipe(pip) < 0) 897 error("Pipe call failed: %s", strerror(errno)); 898 } 899 if (forkshell(jp, cmd, mode) != 0) 900 goto parent; /* at end of routine */ 901 if (flags & EV_BACKCMD) { 902 FORCEINTON; 903 close(pip[0]); 904 if (pip[1] != 1) { 905 dup2(pip[1], 1); 906 close(pip[1]); 907 } 908 } 909 flags |= EV_EXIT; 910 } 911 912 /* This is the child process if a fork occurred. */ 913 /* Execute the command. */ 914 if (cmdentry.cmdtype == CMDFUNCTION) { 915 #ifdef DEBUG 916 trputs("Shell function: "); trargs(argv); 917 #endif 918 saveparam = shellparam; 919 shellparam.malloc = 0; 920 shellparam.reset = 1; 921 shellparam.nparam = argc - 1; 922 shellparam.p = argv + 1; 923 shellparam.optnext = NULL; 924 INTOFF; 925 savelocalvars = localvars; 926 localvars = NULL; 927 reffunc(cmdentry.u.func); 928 savehandler = handler; 929 if (setjmp(jmploc.loc)) { 930 freeparam(&shellparam); 931 shellparam = saveparam; 932 popredir(); 933 unreffunc(cmdentry.u.func); 934 poplocalvars(); 935 localvars = savelocalvars; 936 funcnest--; 937 handler = savehandler; 938 longjmp(handler->loc, 1); 939 } 940 handler = &jmploc; 941 funcnest++; 942 redirect(cmd->ncmd.redirect, REDIR_PUSH); 943 INTON; 944 for (sp = varlist.list ; sp ; sp = sp->next) 945 mklocal(sp->text); 946 exitstatus = oexitstatus; 947 evaltree(getfuncnode(cmdentry.u.func), 948 flags & (EV_TESTED | EV_EXIT)); 949 INTOFF; 950 unreffunc(cmdentry.u.func); 951 poplocalvars(); 952 localvars = savelocalvars; 953 freeparam(&shellparam); 954 shellparam = saveparam; 955 handler = savehandler; 956 funcnest--; 957 popredir(); 958 INTON; 959 if (evalskip == SKIPFUNC) { 960 evalskip = 0; 961 skipcount = 0; 962 } 963 if (jp) 964 exitshell(exitstatus); 965 } else if (cmdentry.cmdtype == CMDBUILTIN) { 966 #ifdef DEBUG 967 trputs("builtin command: "); trargs(argv); 968 #endif 969 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 970 if (flags == EV_BACKCMD) { 971 memout.nleft = 0; 972 memout.nextc = memout.buf; 973 memout.bufsize = 64; 974 mode |= REDIR_BACKQ; 975 cmdentry.special = 0; 976 } 977 savecmdname = commandname; 978 savetopfile = getcurrentfile(); 979 cmdenviron = varlist.list; 980 e = -1; 981 savehandler = handler; 982 if (setjmp(jmploc.loc)) { 983 e = exception; 984 if (e == EXINT) 985 exitstatus = SIGINT+128; 986 else if (e != EXEXIT) 987 exitstatus = 2; 988 goto cmddone; 989 } 990 handler = &jmploc; 991 redirect(cmd->ncmd.redirect, mode); 992 /* 993 * If there is no command word, redirection errors should 994 * not be fatal but assignment errors should. 995 */ 996 if (argc == 0 && !(flags & EV_BACKCMD)) 997 cmdentry.special = 1; 998 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 999 if (argc > 0) 1000 bltinsetlocale(); 1001 commandname = argv[0]; 1002 argptr = argv + 1; 1003 nextopt_optptr = NULL; /* initialize nextopt */ 1004 builtin_flags = flags; 1005 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1006 flushall(); 1007 cmddone: 1008 if (argc > 0) 1009 bltinunsetlocale(); 1010 cmdenviron = NULL; 1011 out1 = &output; 1012 out2 = &errout; 1013 freestdout(); 1014 handler = savehandler; 1015 commandname = savecmdname; 1016 if (jp) 1017 exitshell(exitstatus); 1018 if (flags == EV_BACKCMD) { 1019 backcmd->buf = memout.buf; 1020 backcmd->nleft = memout.nextc - memout.buf; 1021 memout.buf = NULL; 1022 } 1023 if (cmdentry.u.index != EXECCMD) 1024 popredir(); 1025 if (e != -1) { 1026 if ((e != EXERROR && e != EXEXEC) 1027 || cmdentry.special) 1028 exraise(e); 1029 popfilesupto(savetopfile); 1030 if (flags != EV_BACKCMD) 1031 FORCEINTON; 1032 } 1033 } else { 1034 #ifdef DEBUG 1035 trputs("normal command: "); trargs(argv); 1036 #endif 1037 redirect(cmd->ncmd.redirect, 0); 1038 for (sp = varlist.list ; sp ; sp = sp->next) 1039 setvareq(sp->text, VEXPORT|VSTACK); 1040 envp = environment(); 1041 shellexec(argv, envp, path, cmdentry.u.index); 1042 /*NOTREACHED*/ 1043 } 1044 goto out; 1045 1046 parent: /* parent process gets here (if we forked) */ 1047 if (mode == FORK_FG) { /* argument to fork */ 1048 INTOFF; 1049 exitstatus = waitforjob(jp, &realstatus); 1050 INTON; 1051 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1052 evalskip = SKIPBREAK; 1053 skipcount = loopnest; 1054 } 1055 } else if (mode == FORK_NOJOB) { 1056 backcmd->fd = pip[0]; 1057 close(pip[1]); 1058 backcmd->jp = jp; 1059 } else 1060 exitstatus = 0; 1061 1062 out: 1063 if (lastarg) 1064 setvar("_", lastarg, 0); 1065 if (do_clearcmdentry) 1066 clearcmdentry(); 1067 popstackmark(&smark); 1068 } 1069 1070 1071 1072 /* 1073 * Search for a command. This is called before we fork so that the 1074 * location of the command will be available in the parent as well as 1075 * the child. The check for "goodname" is an overly conservative 1076 * check that the name will not be subject to expansion. 1077 */ 1078 1079 static void 1080 prehash(union node *n) 1081 { 1082 struct cmdentry entry; 1083 1084 if (n && n->type == NCMD && n->ncmd.args) 1085 if (goodname(n->ncmd.args->narg.text)) 1086 find_command(n->ncmd.args->narg.text, &entry, 0, 1087 pathval()); 1088 } 1089 1090 1091 1092 /* 1093 * Builtin commands. Builtin commands whose functions are closely 1094 * tied to evaluation are implemented here. 1095 */ 1096 1097 /* 1098 * No command given, a bltin command with no arguments, or a bltin command 1099 * with an invalid name. 1100 */ 1101 1102 int 1103 bltincmd(int argc, char **argv) 1104 { 1105 if (argc > 1) { 1106 out2fmt_flush("%s: not found\n", argv[1]); 1107 return 127; 1108 } 1109 /* 1110 * Preserve exitstatus of a previous possible redirection 1111 * as POSIX mandates 1112 */ 1113 return exitstatus; 1114 } 1115 1116 1117 /* 1118 * Handle break and continue commands. Break, continue, and return are 1119 * all handled by setting the evalskip flag. The evaluation routines 1120 * above all check this flag, and if it is set they start skipping 1121 * commands rather than executing them. The variable skipcount is 1122 * the number of loops to break/continue, or the number of function 1123 * levels to return. (The latter is always 1.) It should probably 1124 * be an error to break out of more loops than exist, but it isn't 1125 * in the standard shell so we don't make it one here. 1126 */ 1127 1128 int 1129 breakcmd(int argc, char **argv) 1130 { 1131 int n = argc > 1 ? number(argv[1]) : 1; 1132 1133 if (n > loopnest) 1134 n = loopnest; 1135 if (n > 0) { 1136 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1137 skipcount = n; 1138 } 1139 return 0; 1140 } 1141 1142 /* 1143 * The `command' command. 1144 */ 1145 int 1146 commandcmd(int argc, char **argv) 1147 { 1148 const char *path; 1149 int ch; 1150 int cmd = -1; 1151 1152 path = bltinlookup("PATH", 1); 1153 1154 optind = optreset = 1; 1155 opterr = 0; 1156 while ((ch = getopt(argc, argv, "pvV")) != -1) { 1157 switch (ch) { 1158 case 'p': 1159 path = _PATH_STDPATH; 1160 break; 1161 case 'v': 1162 cmd = TYPECMD_SMALLV; 1163 break; 1164 case 'V': 1165 cmd = TYPECMD_BIGV; 1166 break; 1167 case '?': 1168 default: 1169 error("unknown option: -%c", optopt); 1170 } 1171 } 1172 argc -= optind; 1173 argv += optind; 1174 1175 if (cmd != -1) { 1176 if (argc != 1) 1177 error("wrong number of arguments"); 1178 return typecmd_impl(2, argv - 1, cmd, path); 1179 } 1180 if (argc != 0) 1181 error("commandcmd bad call"); 1182 1183 /* 1184 * Do nothing successfully if no command was specified; 1185 * ksh also does this. 1186 */ 1187 return(0); 1188 } 1189 1190 1191 /* 1192 * The return command. 1193 */ 1194 1195 int 1196 returncmd(int argc, char **argv) 1197 { 1198 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1199 1200 if (funcnest) { 1201 evalskip = SKIPFUNC; 1202 skipcount = 1; 1203 } else { 1204 /* skip the rest of the file */ 1205 evalskip = SKIPFILE; 1206 skipcount = 1; 1207 } 1208 return ret; 1209 } 1210 1211 1212 int 1213 falsecmd(int argc __unused, char **argv __unused) 1214 { 1215 return 1; 1216 } 1217 1218 1219 int 1220 truecmd(int argc __unused, char **argv __unused) 1221 { 1222 return 0; 1223 } 1224 1225 1226 int 1227 execcmd(int argc, char **argv) 1228 { 1229 /* 1230 * Because we have historically not supported any options, 1231 * only treat "--" specially. 1232 */ 1233 if (argc > 1 && strcmp(argv[1], "--") == 0) 1234 argc--, argv++; 1235 if (argc > 1) { 1236 struct strlist *sp; 1237 1238 iflag = 0; /* exit on error */ 1239 mflag = 0; 1240 optschanged(); 1241 for (sp = cmdenviron; sp ; sp = sp->next) 1242 setvareq(sp->text, VEXPORT|VSTACK); 1243 shellexec(argv + 1, environment(), pathval(), 0); 1244 1245 } 1246 return 0; 1247 } 1248 1249 1250 int 1251 timescmd(int argc __unused, char **argv __unused) 1252 { 1253 struct rusage ru; 1254 long shumins, shsmins, chumins, chsmins; 1255 double shusecs, shssecs, chusecs, chssecs; 1256 1257 if (getrusage(RUSAGE_SELF, &ru) < 0) 1258 return 1; 1259 shumins = ru.ru_utime.tv_sec / 60; 1260 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1261 shsmins = ru.ru_stime.tv_sec / 60; 1262 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1263 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1264 return 1; 1265 chumins = ru.ru_utime.tv_sec / 60; 1266 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1267 chsmins = ru.ru_stime.tv_sec / 60; 1268 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1269 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1270 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1271 return 0; 1272 } 1273