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 1.114 2011/11/27 00:09:59 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 union node *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); 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 next = 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 } 348 *arglist.lastp = NULL; 349 350 exitstatus = 0; 351 loopnest++; 352 for (sp = arglist.list ; sp ; sp = sp->next) { 353 setvar(n->nfor.var, sp->text, 0); 354 evaltree(n->nfor.body, flags); 355 if (evalskip) { 356 if (evalskip == SKIPCONT && --skipcount <= 0) { 357 evalskip = 0; 358 continue; 359 } 360 if (evalskip == SKIPBREAK && --skipcount <= 0) 361 evalskip = 0; 362 break; 363 } 364 } 365 loopnest--; 366 popstackmark(&smark); 367 } 368 369 370 371 static union node * 372 evalcase(union node *n, int flags) 373 { 374 union node *cp; 375 union node *patp; 376 struct arglist arglist; 377 struct stackmark smark; 378 379 setstackmark(&smark); 380 arglist.lastp = &arglist.list; 381 oexitstatus = exitstatus; 382 exitstatus = 0; 383 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 384 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) { 385 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 386 if (casematch(patp, arglist.list->text)) { 387 popstackmark(&smark); 388 while (cp->nclist.next && 389 cp->type == NCLISTFALLTHRU) { 390 evaltree(cp->nclist.body, 391 flags & ~EV_EXIT); 392 if (evalskip != 0) 393 return (NULL); 394 cp = cp->nclist.next; 395 } 396 return (cp->nclist.body); 397 } 398 } 399 } 400 popstackmark(&smark); 401 return (NULL); 402 } 403 404 405 406 /* 407 * Kick off a subshell to evaluate a tree. 408 */ 409 410 static void 411 evalsubshell(union node *n, int flags) 412 { 413 struct job *jp; 414 int backgnd = (n->type == NBACKGND); 415 416 oexitstatus = exitstatus; 417 expredir(n->nredir.redirect); 418 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 419 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 420 if (backgnd) 421 flags &=~ EV_TESTED; 422 redirect(n->nredir.redirect, 0); 423 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 424 } else if (!backgnd) { 425 INTOFF; 426 exitstatus = waitforjob(jp, NULL); 427 INTON; 428 } else 429 exitstatus = 0; 430 } 431 432 433 /* 434 * Evaluate a redirected compound command. 435 */ 436 437 static void 438 evalredir(union node *n, int flags) 439 { 440 struct jmploc jmploc; 441 struct jmploc *savehandler; 442 volatile int in_redirect = 1; 443 444 oexitstatus = exitstatus; 445 expredir(n->nredir.redirect); 446 savehandler = handler; 447 if (setjmp(jmploc.loc)) { 448 int e; 449 450 handler = savehandler; 451 e = exception; 452 popredir(); 453 if (e == EXERROR || e == EXEXEC) { 454 if (in_redirect) { 455 exitstatus = 2; 456 return; 457 } 458 } 459 longjmp(handler->loc, 1); 460 } else { 461 INTOFF; 462 handler = &jmploc; 463 redirect(n->nredir.redirect, REDIR_PUSH); 464 in_redirect = 0; 465 INTON; 466 evaltree(n->nredir.n, flags); 467 } 468 INTOFF; 469 handler = savehandler; 470 popredir(); 471 INTON; 472 } 473 474 475 /* 476 * Compute the names of the files in a redirection list. 477 */ 478 479 static void 480 expredir(union node *n) 481 { 482 union node *redir; 483 484 for (redir = n ; redir ; redir = redir->nfile.next) { 485 struct arglist fn; 486 fn.lastp = &fn.list; 487 switch (redir->type) { 488 case NFROM: 489 case NTO: 490 case NFROMTO: 491 case NAPPEND: 492 case NCLOBBER: 493 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 494 redir->nfile.expfname = fn.list->text; 495 break; 496 case NFROMFD: 497 case NTOFD: 498 if (redir->ndup.vname) { 499 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 500 fixredir(redir, fn.list->text, 1); 501 } 502 break; 503 } 504 } 505 } 506 507 508 509 /* 510 * Evaluate a pipeline. All the processes in the pipeline are children 511 * of the process creating the pipeline. (This differs from some versions 512 * of the shell, which make the last process in a pipeline the parent 513 * of all the rest.) 514 */ 515 516 static void 517 evalpipe(union node *n) 518 { 519 struct job *jp; 520 struct nodelist *lp; 521 int pipelen; 522 int prevfd; 523 int pip[2]; 524 525 TRACE(("evalpipe(%p) called\n", (void *)n)); 526 pipelen = 0; 527 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 528 pipelen++; 529 INTOFF; 530 jp = makejob(n, pipelen); 531 prevfd = -1; 532 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 533 prehash(lp->n); 534 pip[1] = -1; 535 if (lp->next) { 536 if (pipe(pip) < 0) { 537 if (prevfd >= 0) 538 close(prevfd); 539 error("Pipe call failed: %s", strerror(errno)); 540 } 541 } 542 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 543 INTON; 544 if (prevfd > 0) { 545 dup2(prevfd, 0); 546 close(prevfd); 547 } 548 if (pip[1] >= 0) { 549 if (!(prevfd >= 0 && pip[0] == 0)) 550 close(pip[0]); 551 if (pip[1] != 1) { 552 dup2(pip[1], 1); 553 close(pip[1]); 554 } 555 } 556 evaltree(lp->n, EV_EXIT); 557 } 558 if (prevfd >= 0) 559 close(prevfd); 560 prevfd = pip[0]; 561 if (pip[1] != -1) 562 close(pip[1]); 563 } 564 INTON; 565 if (n->npipe.backgnd == 0) { 566 INTOFF; 567 exitstatus = waitforjob(jp, NULL); 568 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 569 INTON; 570 } else 571 exitstatus = 0; 572 } 573 574 575 576 static int 577 is_valid_fast_cmdsubst(union node *n) 578 { 579 580 return (n->type == NCMD); 581 } 582 583 /* 584 * Execute a command inside back quotes. If it's a builtin command, we 585 * want to save its output in a block obtained from malloc. Otherwise 586 * we fork off a subprocess and get the output of the command via a pipe. 587 * Should be called with interrupts off. 588 */ 589 590 void 591 evalbackcmd(union node *n, struct backcmd *result) 592 { 593 int pip[2]; 594 struct job *jp; 595 struct stackmark smark; /* unnecessary */ 596 struct jmploc jmploc; 597 struct jmploc *savehandler; 598 struct localvar *savelocalvars; 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 savelocalvars = localvars; 612 localvars = NULL; 613 forcelocal++; 614 savehandler = handler; 615 if (setjmp(jmploc.loc)) { 616 if (exception == EXERROR || exception == EXEXEC) 617 exitstatus = 2; 618 else if (exception != 0) { 619 handler = savehandler; 620 forcelocal--; 621 poplocalvars(); 622 localvars = savelocalvars; 623 longjmp(handler->loc, 1); 624 } 625 } else { 626 handler = &jmploc; 627 evalcommand(n, EV_BACKCMD, result); 628 } 629 handler = savehandler; 630 forcelocal--; 631 poplocalvars(); 632 localvars = savelocalvars; 633 } else { 634 exitstatus = 0; 635 if (pipe(pip) < 0) 636 error("Pipe call failed: %s", strerror(errno)); 637 jp = makejob(n, 1); 638 if (forkshell(jp, n, FORK_NOJOB) == 0) { 639 FORCEINTON; 640 close(pip[0]); 641 if (pip[1] != 1) { 642 dup2(pip[1], 1); 643 close(pip[1]); 644 } 645 evaltree(n, EV_EXIT); 646 } 647 close(pip[1]); 648 result->fd = pip[0]; 649 result->jp = jp; 650 } 651 out: 652 popstackmark(&smark); 653 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 654 result->fd, result->buf, result->nleft, result->jp)); 655 } 656 657 /* 658 * Check if a builtin can safely be executed in the same process, 659 * even though it should be in a subshell (command substitution). 660 * Note that jobid, jobs, times and trap can show information not 661 * available in a child process; this is deliberate. 662 * The arguments should already have been expanded. 663 */ 664 static int 665 safe_builtin(int idx, int argc, char **argv) 666 { 667 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 668 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 669 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 670 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 671 idx == TYPECMD) 672 return (1); 673 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 674 idx == UMASKCMD) 675 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 676 if (idx == SETCMD) 677 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 678 argv[1][0] == '+') && argv[1][1] == 'o' && 679 argv[1][2] == '\0')); 680 return (0); 681 } 682 683 /* 684 * Execute a simple command. 685 * Note: This may or may not return if (flags & EV_EXIT). 686 */ 687 688 static void 689 evalcommand(union node *cmd, int flgs, struct backcmd *backcmd) 690 { 691 struct stackmark smark; 692 union node *argp; 693 struct arglist arglist; 694 struct arglist varlist; 695 volatile int flags = flgs; 696 char **volatile argv; 697 volatile int argc; 698 char **envp; 699 int varflag; 700 struct strlist *sp; 701 int mode; 702 int pip[2]; 703 struct cmdentry cmdentry; 704 struct job *volatile jp; 705 struct jmploc jmploc; 706 struct jmploc *savehandler; 707 const char *savecmdname; 708 struct shparam saveparam; 709 struct localvar *savelocalvars; 710 struct parsefile *savetopfile; 711 volatile int e; 712 char *volatile lastarg; 713 int realstatus; 714 volatile int do_clearcmdentry; 715 const char *path = pathval(); 716 717 /* First expand the arguments. */ 718 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 719 setstackmark(&smark); 720 arglist.lastp = &arglist.list; 721 varlist.lastp = &varlist.list; 722 varflag = 1; 723 jp = NULL; 724 do_clearcmdentry = 0; 725 oexitstatus = exitstatus; 726 exitstatus = 0; 727 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 728 if (varflag && isassignment(argp->narg.text)) { 729 expandarg(argp, &varlist, EXP_VARTILDE); 730 continue; 731 } 732 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 733 varflag = 0; 734 } 735 *arglist.lastp = NULL; 736 *varlist.lastp = NULL; 737 expredir(cmd->ncmd.redirect); 738 argc = 0; 739 for (sp = arglist.list ; sp ; sp = sp->next) 740 argc++; 741 /* Add one slot at the beginning for tryexec(). */ 742 argv = stalloc(sizeof (char *) * (argc + 2)); 743 argv++; 744 745 for (sp = arglist.list ; sp ; sp = sp->next) { 746 TRACE(("evalcommand arg: %s\n", sp->text)); 747 *argv++ = sp->text; 748 } 749 *argv = NULL; 750 lastarg = NULL; 751 if (iflag && funcnest == 0 && argc > 0) 752 lastarg = argv[-1]; 753 argv -= argc; 754 755 /* Print the command if xflag is set. */ 756 if (xflag) { 757 char sep = 0; 758 const char *p, *ps4; 759 ps4 = expandstr(ps4val()); 760 out2str(ps4 != NULL ? ps4 : ps4val()); 761 for (sp = varlist.list ; sp ; sp = sp->next) { 762 if (sep != 0) 763 out2c(' '); 764 p = strchr(sp->text, '='); 765 if (p != NULL) { 766 p++; 767 outbin(sp->text, p - sp->text, out2); 768 out2qstr(p); 769 } else 770 out2qstr(sp->text); 771 sep = ' '; 772 } 773 for (sp = arglist.list ; sp ; sp = sp->next) { 774 if (sep != 0) 775 out2c(' '); 776 /* Disambiguate command looking like assignment. */ 777 if (sp == arglist.list && 778 strchr(sp->text, '=') != NULL && 779 strchr(sp->text, '\'') == NULL) { 780 out2c('\''); 781 out2str(sp->text); 782 out2c('\''); 783 } else 784 out2qstr(sp->text); 785 sep = ' '; 786 } 787 out2c('\n'); 788 flushout(&errout); 789 } 790 791 /* Now locate the command. */ 792 if (argc == 0) { 793 /* Variable assignment(s) without command */ 794 cmdentry.cmdtype = CMDBUILTIN; 795 cmdentry.u.index = BLTINCMD; 796 cmdentry.special = 0; 797 } else { 798 static const char PATH[] = "PATH="; 799 int cmd_flags = 0, bltinonly = 0; 800 801 /* 802 * Modify the command lookup path, if a PATH= assignment 803 * is present 804 */ 805 for (sp = varlist.list ; sp ; sp = sp->next) 806 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 807 path = sp->text + sizeof(PATH) - 1; 808 /* 809 * On `PATH=... command`, we need to make 810 * sure that the command isn't using the 811 * non-updated hash table of the outer PATH 812 * setting and we need to make sure that 813 * the hash table isn't filled with items 814 * from the temporary setting. 815 * 816 * It would be better to forbit using and 817 * updating the table while this command 818 * runs, by the command finding mechanism 819 * is heavily integrated with hash handling, 820 * so we just delete the hash before and after 821 * the command runs. Partly deleting like 822 * changepatch() does doesn't seem worth the 823 * bookinging effort, since most such runs add 824 * directories in front of the new PATH. 825 */ 826 clearcmdentry(); 827 do_clearcmdentry = 1; 828 } 829 830 for (;;) { 831 if (bltinonly) { 832 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 833 if (cmdentry.u.index < 0) { 834 cmdentry.u.index = BLTINCMD; 835 argv--; 836 argc++; 837 break; 838 } 839 } else 840 find_command(argv[0], &cmdentry, cmd_flags, path); 841 /* implement the bltin and command builtins here */ 842 if (cmdentry.cmdtype != CMDBUILTIN) 843 break; 844 if (cmdentry.u.index == BLTINCMD) { 845 if (argc == 1) 846 break; 847 argv++; 848 argc--; 849 bltinonly = 1; 850 } else if (cmdentry.u.index == COMMANDCMD) { 851 if (argc == 1) 852 break; 853 if (!strcmp(argv[1], "-p")) { 854 if (argc == 2) 855 break; 856 if (argv[2][0] == '-') { 857 if (strcmp(argv[2], "--")) 858 break; 859 if (argc == 3) 860 break; 861 argv += 3; 862 argc -= 3; 863 } else { 864 argv += 2; 865 argc -= 2; 866 } 867 path = _PATH_STDPATH; 868 clearcmdentry(); 869 do_clearcmdentry = 1; 870 } else if (!strcmp(argv[1], "--")) { 871 if (argc == 2) 872 break; 873 argv += 2; 874 argc -= 2; 875 } else if (argv[1][0] == '-') 876 break; 877 else { 878 argv++; 879 argc--; 880 } 881 cmd_flags |= DO_NOFUNC; 882 bltinonly = 0; 883 } else 884 break; 885 } 886 /* 887 * Special builtins lose their special properties when 888 * called via 'command'. 889 */ 890 if (cmd_flags & DO_NOFUNC) 891 cmdentry.special = 0; 892 } 893 894 /* Fork off a child process if necessary. */ 895 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 896 && ((flags & EV_EXIT) == 0 || have_traps())) 897 || ((flags & EV_BACKCMD) != 0 898 && (cmdentry.cmdtype != CMDBUILTIN || 899 !safe_builtin(cmdentry.u.index, argc, argv)))) { 900 jp = makejob(cmd, 1); 901 mode = FORK_FG; 902 if (flags & EV_BACKCMD) { 903 mode = FORK_NOJOB; 904 if (pipe(pip) < 0) 905 error("Pipe call failed: %s", strerror(errno)); 906 } 907 if (forkshell(jp, cmd, mode) != 0) 908 goto parent; /* at end of routine */ 909 if (flags & EV_BACKCMD) { 910 FORCEINTON; 911 close(pip[0]); 912 if (pip[1] != 1) { 913 dup2(pip[1], 1); 914 close(pip[1]); 915 } 916 flags &= ~EV_BACKCMD; 917 } 918 flags |= EV_EXIT; 919 } 920 921 /* This is the child process if a fork occurred. */ 922 /* Execute the command. */ 923 if (cmdentry.cmdtype == CMDFUNCTION) { 924 #ifdef DEBUG 925 trputs("Shell function: "); trargs(argv); 926 #endif 927 saveparam = shellparam; 928 shellparam.malloc = 0; 929 shellparam.reset = 1; 930 shellparam.nparam = argc - 1; 931 shellparam.p = argv + 1; 932 shellparam.optnext = NULL; 933 INTOFF; 934 savelocalvars = localvars; 935 localvars = NULL; 936 reffunc(cmdentry.u.func); 937 savehandler = handler; 938 if (setjmp(jmploc.loc)) { 939 freeparam(&shellparam); 940 shellparam = saveparam; 941 popredir(); 942 unreffunc(cmdentry.u.func); 943 poplocalvars(); 944 localvars = savelocalvars; 945 funcnest--; 946 handler = savehandler; 947 longjmp(handler->loc, 1); 948 } 949 handler = &jmploc; 950 funcnest++; 951 redirect(cmd->ncmd.redirect, REDIR_PUSH); 952 INTON; 953 for (sp = varlist.list ; sp ; sp = sp->next) 954 mklocal(sp->text); 955 exitstatus = oexitstatus; 956 evaltree(getfuncnode(cmdentry.u.func), 957 flags & (EV_TESTED | EV_EXIT)); 958 INTOFF; 959 unreffunc(cmdentry.u.func); 960 poplocalvars(); 961 localvars = savelocalvars; 962 freeparam(&shellparam); 963 shellparam = saveparam; 964 handler = savehandler; 965 funcnest--; 966 popredir(); 967 INTON; 968 if (evalskip == SKIPFUNC) { 969 evalskip = 0; 970 skipcount = 0; 971 } 972 if (jp) 973 exitshell(exitstatus); 974 } else if (cmdentry.cmdtype == CMDBUILTIN) { 975 #ifdef DEBUG 976 trputs("builtin command: "); trargs(argv); 977 #endif 978 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 979 if (flags == EV_BACKCMD) { 980 memout.nleft = 0; 981 memout.nextc = memout.buf; 982 memout.bufsize = 64; 983 mode |= REDIR_BACKQ; 984 cmdentry.special = 0; 985 } 986 savecmdname = commandname; 987 savetopfile = getcurrentfile(); 988 cmdenviron = varlist.list; 989 e = -1; 990 savehandler = handler; 991 if (setjmp(jmploc.loc)) { 992 e = exception; 993 if (e == EXINT) 994 exitstatus = SIGINT+128; 995 else if (e != EXEXIT) 996 exitstatus = 2; 997 goto cmddone; 998 } 999 handler = &jmploc; 1000 redirect(cmd->ncmd.redirect, mode); 1001 /* 1002 * If there is no command word, redirection errors should 1003 * not be fatal but assignment errors should. 1004 */ 1005 if (argc == 0 && !(flags & EV_BACKCMD)) 1006 cmdentry.special = 1; 1007 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1008 if (argc > 0) 1009 bltinsetlocale(); 1010 commandname = argv[0]; 1011 argptr = argv + 1; 1012 nextopt_optptr = NULL; /* initialize nextopt */ 1013 builtin_flags = flags; 1014 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1015 flushall(); 1016 cmddone: 1017 if (argc > 0) 1018 bltinunsetlocale(); 1019 cmdenviron = NULL; 1020 out1 = &output; 1021 out2 = &errout; 1022 freestdout(); 1023 handler = savehandler; 1024 commandname = savecmdname; 1025 if (jp) 1026 exitshell(exitstatus); 1027 if (flags == EV_BACKCMD) { 1028 backcmd->buf = memout.buf; 1029 backcmd->nleft = memout.nextc - memout.buf; 1030 memout.buf = NULL; 1031 } 1032 if (cmdentry.u.index != EXECCMD) 1033 popredir(); 1034 if (e != -1) { 1035 if ((e != EXERROR && e != EXEXEC) 1036 || cmdentry.special) 1037 exraise(e); 1038 popfilesupto(savetopfile); 1039 if (flags != EV_BACKCMD) 1040 FORCEINTON; 1041 } 1042 } else { 1043 #ifdef DEBUG 1044 trputs("normal command: "); trargs(argv); 1045 #endif 1046 redirect(cmd->ncmd.redirect, 0); 1047 for (sp = varlist.list ; sp ; sp = sp->next) 1048 setvareq(sp->text, VEXPORT|VSTACK); 1049 envp = environment(); 1050 shellexec(argv, envp, path, cmdentry.u.index); 1051 /*NOTREACHED*/ 1052 } 1053 goto out; 1054 1055 parent: /* parent process gets here (if we forked) */ 1056 if (mode == FORK_FG) { /* argument to fork */ 1057 INTOFF; 1058 exitstatus = waitforjob(jp, &realstatus); 1059 INTON; 1060 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1061 evalskip = SKIPBREAK; 1062 skipcount = loopnest; 1063 } 1064 } else if (mode == FORK_NOJOB) { 1065 backcmd->fd = pip[0]; 1066 close(pip[1]); 1067 backcmd->jp = jp; 1068 } 1069 1070 out: 1071 if (lastarg) 1072 setvar("_", lastarg, 0); 1073 if (do_clearcmdentry) 1074 clearcmdentry(); 1075 popstackmark(&smark); 1076 } 1077 1078 1079 1080 /* 1081 * Search for a command. This is called before we fork so that the 1082 * location of the command will be available in the parent as well as 1083 * the child. The check for "goodname" is an overly conservative 1084 * check that the name will not be subject to expansion. 1085 */ 1086 1087 static void 1088 prehash(union node *n) 1089 { 1090 struct cmdentry entry; 1091 1092 if (n && n->type == NCMD && n->ncmd.args) 1093 if (goodname(n->ncmd.args->narg.text)) 1094 find_command(n->ncmd.args->narg.text, &entry, 0, 1095 pathval()); 1096 } 1097 1098 1099 1100 /* 1101 * Builtin commands. Builtin commands whose functions are closely 1102 * tied to evaluation are implemented here. 1103 */ 1104 1105 /* 1106 * No command given, a bltin command with no arguments, or a bltin command 1107 * with an invalid name. 1108 */ 1109 1110 int 1111 bltincmd(int argc, char **argv) 1112 { 1113 if (argc > 1) { 1114 out2fmt_flush("%s: not found\n", argv[1]); 1115 return 127; 1116 } 1117 /* 1118 * Preserve exitstatus of a previous possible redirection 1119 * as POSIX mandates 1120 */ 1121 return exitstatus; 1122 } 1123 1124 1125 /* 1126 * Handle break and continue commands. Break, continue, and return are 1127 * all handled by setting the evalskip flag. The evaluation routines 1128 * above all check this flag, and if it is set they start skipping 1129 * commands rather than executing them. The variable skipcount is 1130 * the number of loops to break/continue, or the number of function 1131 * levels to return. (The latter is always 1.) It should probably 1132 * be an error to break out of more loops than exist, but it isn't 1133 * in the standard shell so we don't make it one here. 1134 */ 1135 1136 int 1137 breakcmd(int argc, char **argv) 1138 { 1139 int n = argc > 1 ? number(argv[1]) : 1; 1140 1141 if (n > loopnest) 1142 n = loopnest; 1143 if (n > 0) { 1144 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1145 skipcount = n; 1146 } 1147 return 0; 1148 } 1149 1150 /* 1151 * The `command' command. 1152 */ 1153 int 1154 commandcmd(int argc, char **argv) 1155 { 1156 const char *path; 1157 int ch; 1158 int cmd = -1; 1159 1160 path = bltinlookup("PATH", 1); 1161 1162 optind = optreset = 1; 1163 opterr = 0; 1164 while ((ch = getopt(argc, argv, "pvV")) != -1) { 1165 switch (ch) { 1166 case 'p': 1167 path = _PATH_STDPATH; 1168 break; 1169 case 'v': 1170 cmd = TYPECMD_SMALLV; 1171 break; 1172 case 'V': 1173 cmd = TYPECMD_BIGV; 1174 break; 1175 case '?': 1176 default: 1177 error("unknown option: -%c", optopt); 1178 } 1179 } 1180 argc -= optind; 1181 argv += optind; 1182 1183 if (cmd != -1) { 1184 if (argc != 1) 1185 error("wrong number of arguments"); 1186 return typecmd_impl(2, argv - 1, cmd, path); 1187 } 1188 if (argc != 0) 1189 error("commandcmd bad call"); 1190 1191 /* 1192 * Do nothing successfully if no command was specified; 1193 * ksh also does this. 1194 */ 1195 return(0); 1196 } 1197 1198 1199 /* 1200 * The return command. 1201 */ 1202 1203 int 1204 returncmd(int argc, char **argv) 1205 { 1206 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1207 1208 if (funcnest) { 1209 evalskip = SKIPFUNC; 1210 skipcount = 1; 1211 } else { 1212 /* skip the rest of the file */ 1213 evalskip = SKIPFILE; 1214 skipcount = 1; 1215 } 1216 return ret; 1217 } 1218 1219 1220 int 1221 falsecmd(int argc __unused, char **argv __unused) 1222 { 1223 return 1; 1224 } 1225 1226 1227 int 1228 truecmd(int argc __unused, char **argv __unused) 1229 { 1230 return 0; 1231 } 1232 1233 1234 int 1235 execcmd(int argc, char **argv) 1236 { 1237 /* 1238 * Because we have historically not supported any options, 1239 * only treat "--" specially. 1240 */ 1241 if (argc > 1 && strcmp(argv[1], "--") == 0) 1242 argc--, argv++; 1243 if (argc > 1) { 1244 struct strlist *sp; 1245 1246 iflag = 0; /* exit on error */ 1247 mflag = 0; 1248 optschanged(); 1249 for (sp = cmdenviron; sp ; sp = sp->next) 1250 setvareq(sp->text, VEXPORT|VSTACK); 1251 shellexec(argv + 1, environment(), pathval(), 0); 1252 1253 } 1254 return 0; 1255 } 1256 1257 1258 int 1259 timescmd(int argc __unused, char **argv __unused) 1260 { 1261 struct rusage ru; 1262 long shumins, shsmins, chumins, chsmins; 1263 double shusecs, shssecs, chusecs, chssecs; 1264 1265 if (getrusage(RUSAGE_SELF, &ru) < 0) 1266 return 1; 1267 shumins = ru.ru_utime.tv_sec / 60; 1268 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1269 shsmins = ru.ru_stime.tv_sec / 60; 1270 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1271 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1272 return 1; 1273 chumins = ru.ru_utime.tv_sec / 60; 1274 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1275 chsmins = ru.ru_stime.tv_sec / 60; 1276 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1277 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1278 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1279 return 0; 1280 } 1281