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 1.119 2012/01/22 14:00:33 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 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 *); 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); 261 break; 262 case NCLIST: 263 next = n->nclist.body; 264 break; 265 case NCLISTFALLTHRU: 266 if (n->nclist.body) { 267 evaltree(n->nclist.body, flags & ~EV_EXIT); 268 if (evalskip) 269 goto out; 270 } 271 next = n->nclist.next; 272 break; 273 case NDEFUN: 274 defun(n->narg.text, n->narg.next); 275 exitstatus = 0; 276 break; 277 case NNOT: 278 evaltree(n->nnot.com, EV_TESTED); 279 exitstatus = !exitstatus; 280 break; 281 282 case NPIPE: 283 evalpipe(n); 284 do_etest = !(flags & EV_TESTED); 285 break; 286 case NCMD: 287 evalcommand(n, flags, NULL); 288 do_etest = !(flags & EV_TESTED); 289 break; 290 default: 291 out1fmt("Node type = %d\n", n->type); 292 flushout(&output); 293 break; 294 } 295 n = next; 296 } while (n != NULL); 297 out: 298 if (pendingsigs) 299 dotrap(); 300 if (eflag && exitstatus != 0 && do_etest) 301 exitshell(exitstatus); 302 if (flags & EV_EXIT) 303 exraise(EXEXIT); 304 } 305 306 307 static void 308 evalloop(union node *n, int flags) 309 { 310 int status; 311 312 loopnest++; 313 status = 0; 314 for (;;) { 315 evaltree(n->nbinary.ch1, EV_TESTED); 316 if (evalskip) { 317 skipping: if (evalskip == SKIPCONT && --skipcount <= 0) { 318 evalskip = 0; 319 continue; 320 } 321 if (evalskip == SKIPBREAK && --skipcount <= 0) 322 evalskip = 0; 323 if (evalskip == SKIPFUNC || evalskip == SKIPFILE) 324 status = exitstatus; 325 break; 326 } 327 if (n->type == NWHILE) { 328 if (exitstatus != 0) 329 break; 330 } else { 331 if (exitstatus == 0) 332 break; 333 } 334 evaltree(n->nbinary.ch2, flags); 335 status = exitstatus; 336 if (evalskip) 337 goto skipping; 338 } 339 loopnest--; 340 exitstatus = status; 341 } 342 343 344 345 static void 346 evalfor(union node *n, int flags) 347 { 348 struct arglist arglist; 349 union node *argp; 350 struct strlist *sp; 351 struct stackmark smark; 352 int status; 353 354 setstackmark(&smark); 355 arglist.lastp = &arglist.list; 356 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 357 oexitstatus = exitstatus; 358 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 359 } 360 *arglist.lastp = NULL; 361 362 loopnest++; 363 status = 0; 364 for (sp = arglist.list ; sp ; sp = sp->next) { 365 setvar(n->nfor.var, sp->text, 0); 366 evaltree(n->nfor.body, flags); 367 status = exitstatus; 368 if (evalskip) { 369 if (evalskip == SKIPCONT && --skipcount <= 0) { 370 evalskip = 0; 371 continue; 372 } 373 if (evalskip == SKIPBREAK && --skipcount <= 0) 374 evalskip = 0; 375 break; 376 } 377 } 378 loopnest--; 379 popstackmark(&smark); 380 exitstatus = status; 381 } 382 383 384 /* 385 * Evaluate a case statement, returning the selected tree. 386 * 387 * The exit status needs care to get right. 388 */ 389 390 static union node * 391 evalcase(union node *n) 392 { 393 union node *cp; 394 union node *patp; 395 struct arglist arglist; 396 struct stackmark smark; 397 398 setstackmark(&smark); 399 arglist.lastp = &arglist.list; 400 oexitstatus = exitstatus; 401 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 402 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) { 403 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 404 if (casematch(patp, arglist.list->text)) { 405 popstackmark(&smark); 406 while (cp->nclist.next && 407 cp->type == NCLISTFALLTHRU && 408 cp->nclist.body == NULL) 409 cp = cp->nclist.next; 410 if (cp->nclist.next && 411 cp->type == NCLISTFALLTHRU) 412 return (cp); 413 if (cp->nclist.body == NULL) 414 exitstatus = 0; 415 return (cp->nclist.body); 416 } 417 } 418 } 419 popstackmark(&smark); 420 exitstatus = 0; 421 return (NULL); 422 } 423 424 425 426 /* 427 * Kick off a subshell to evaluate a tree. 428 */ 429 430 static void 431 evalsubshell(union node *n, int flags) 432 { 433 struct job *jp; 434 int backgnd = (n->type == NBACKGND); 435 436 oexitstatus = exitstatus; 437 expredir(n->nredir.redirect); 438 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 439 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 440 if (backgnd) 441 flags &=~ EV_TESTED; 442 redirect(n->nredir.redirect, 0); 443 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 444 } else if (!backgnd) { 445 INTOFF; 446 exitstatus = waitforjob(jp, NULL); 447 INTON; 448 } else 449 exitstatus = 0; 450 } 451 452 453 /* 454 * Evaluate a redirected compound command. 455 */ 456 457 static void 458 evalredir(union node *n, int flags) 459 { 460 struct jmploc jmploc; 461 struct jmploc *savehandler; 462 volatile int in_redirect = 1; 463 464 oexitstatus = exitstatus; 465 expredir(n->nredir.redirect); 466 savehandler = handler; 467 if (setjmp(jmploc.loc)) { 468 int e; 469 470 handler = savehandler; 471 e = exception; 472 popredir(); 473 if (e == EXERROR || e == EXEXEC) { 474 if (in_redirect) { 475 exitstatus = 2; 476 return; 477 } 478 } 479 longjmp(handler->loc, 1); 480 } else { 481 INTOFF; 482 handler = &jmploc; 483 redirect(n->nredir.redirect, REDIR_PUSH); 484 in_redirect = 0; 485 INTON; 486 evaltree(n->nredir.n, flags); 487 } 488 INTOFF; 489 handler = savehandler; 490 popredir(); 491 INTON; 492 } 493 494 495 /* 496 * Compute the names of the files in a redirection list. 497 */ 498 499 static void 500 expredir(union node *n) 501 { 502 union node *redir; 503 504 for (redir = n ; redir ; redir = redir->nfile.next) { 505 struct arglist fn; 506 fn.lastp = &fn.list; 507 switch (redir->type) { 508 case NFROM: 509 case NTO: 510 case NFROMTO: 511 case NAPPEND: 512 case NCLOBBER: 513 expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR); 514 redir->nfile.expfname = fn.list->text; 515 break; 516 case NFROMFD: 517 case NTOFD: 518 if (redir->ndup.vname) { 519 expandarg(redir->ndup.vname, &fn, EXP_TILDE | EXP_REDIR); 520 fixredir(redir, fn.list->text, 1); 521 } 522 break; 523 } 524 } 525 } 526 527 528 529 /* 530 * Evaluate a pipeline. All the processes in the pipeline are children 531 * of the process creating the pipeline. (This differs from some versions 532 * of the shell, which make the last process in a pipeline the parent 533 * of all the rest.) 534 */ 535 536 static void 537 evalpipe(union node *n) 538 { 539 struct job *jp; 540 struct nodelist *lp; 541 int pipelen; 542 int prevfd; 543 int pip[2]; 544 545 TRACE(("evalpipe(%p) called\n", (void *)n)); 546 pipelen = 0; 547 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 548 pipelen++; 549 INTOFF; 550 jp = makejob(n, pipelen); 551 prevfd = -1; 552 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 553 prehash(lp->n); 554 pip[1] = -1; 555 if (lp->next) { 556 if (pipe(pip) < 0) { 557 if (prevfd >= 0) 558 close(prevfd); 559 error("Pipe call failed: %s", strerror(errno)); 560 } 561 } 562 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 563 INTON; 564 if (prevfd > 0) { 565 dup2(prevfd, 0); 566 close(prevfd); 567 } 568 if (pip[1] >= 0) { 569 if (!(prevfd >= 0 && pip[0] == 0)) 570 close(pip[0]); 571 if (pip[1] != 1) { 572 dup2(pip[1], 1); 573 close(pip[1]); 574 } 575 } 576 evaltree(lp->n, EV_EXIT); 577 } 578 if (prevfd >= 0) 579 close(prevfd); 580 prevfd = pip[0]; 581 if (pip[1] != -1) 582 close(pip[1]); 583 } 584 INTON; 585 if (n->npipe.backgnd == 0) { 586 INTOFF; 587 exitstatus = waitforjob(jp, NULL); 588 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 589 INTON; 590 } else 591 exitstatus = 0; 592 } 593 594 595 596 static int 597 is_valid_fast_cmdsubst(union node *n) 598 { 599 600 return (n->type == NCMD); 601 } 602 603 /* 604 * Execute a command inside back quotes. If it's a builtin command, we 605 * want to save its output in a block obtained from malloc. Otherwise 606 * we fork off a subprocess and get the output of the command via a pipe. 607 * Should be called with interrupts off. 608 */ 609 610 void 611 evalbackcmd(union node *n, struct backcmd *result) 612 { 613 int pip[2]; 614 struct job *jp; 615 struct stackmark smark; /* unnecessary */ 616 struct jmploc jmploc; 617 struct jmploc *savehandler; 618 struct localvar *savelocalvars; 619 620 setstackmark(&smark); 621 result->fd = -1; 622 result->buf = NULL; 623 result->nleft = 0; 624 result->jp = NULL; 625 if (n == NULL) { 626 exitstatus = 0; 627 goto out; 628 } 629 if (is_valid_fast_cmdsubst(n)) { 630 exitstatus = oexitstatus; 631 savelocalvars = localvars; 632 localvars = NULL; 633 forcelocal++; 634 savehandler = handler; 635 if (setjmp(jmploc.loc)) { 636 if (exception == EXERROR || exception == EXEXEC) 637 exitstatus = 2; 638 else if (exception != 0) { 639 handler = savehandler; 640 forcelocal--; 641 poplocalvars(); 642 localvars = savelocalvars; 643 longjmp(handler->loc, 1); 644 } 645 } else { 646 handler = &jmploc; 647 evalcommand(n, EV_BACKCMD, result); 648 } 649 handler = savehandler; 650 forcelocal--; 651 poplocalvars(); 652 localvars = savelocalvars; 653 } else { 654 exitstatus = 0; 655 if (pipe(pip) < 0) 656 error("Pipe call failed: %s", strerror(errno)); 657 jp = makejob(n, 1); 658 if (forkshell(jp, n, FORK_NOJOB) == 0) { 659 FORCEINTON; 660 close(pip[0]); 661 if (pip[1] != 1) { 662 dup2(pip[1], 1); 663 close(pip[1]); 664 } 665 evaltree(n, EV_EXIT); 666 } 667 close(pip[1]); 668 result->fd = pip[0]; 669 result->jp = jp; 670 } 671 out: 672 popstackmark(&smark); 673 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 674 result->fd, result->buf, result->nleft, result->jp)); 675 } 676 677 /* 678 * Check if a builtin can safely be executed in the same process, 679 * even though it should be in a subshell (command substitution). 680 * Note that jobid, jobs, times and trap can show information not 681 * available in a child process; this is deliberate. 682 * The arguments should already have been expanded. 683 */ 684 static int 685 safe_builtin(int idx, int argc, char **argv) 686 { 687 if (idx == BLTINCMD || idx == COMMANDCMD || idx == ECHOCMD || 688 idx == FALSECMD || idx == JOBIDCMD || idx == JOBSCMD || 689 idx == KILLCMD || idx == PRINTFCMD || idx == PWDCMD || 690 idx == TESTCMD || idx == TIMESCMD || idx == TRUECMD || 691 idx == TYPECMD) 692 return (1); 693 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 694 idx == UMASKCMD) 695 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 696 if (idx == SETCMD) 697 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 698 argv[1][0] == '+') && argv[1][1] == 'o' && 699 argv[1][2] == '\0')); 700 return (0); 701 } 702 703 /* 704 * Execute a simple command. 705 * Note: This may or may not return if (flags & EV_EXIT). 706 */ 707 708 static void 709 evalcommand(union node *cmd, int flgs, struct backcmd *backcmd) 710 { 711 struct stackmark smark; 712 union node *argp; 713 struct arglist arglist; 714 struct arglist varlist; 715 volatile int flags = flgs; 716 char **volatile argv; 717 volatile int argc; 718 char **envp; 719 int varflag; 720 struct strlist *sp; 721 int mode; 722 int pip[2]; 723 struct cmdentry cmdentry; 724 struct job *volatile jp; 725 struct jmploc jmploc; 726 struct jmploc *savehandler; 727 const char *savecmdname; 728 struct shparam saveparam; 729 struct localvar *savelocalvars; 730 struct parsefile *savetopfile; 731 volatile int e; 732 char *volatile lastarg; 733 int realstatus; 734 volatile int do_clearcmdentry; 735 const char *path = pathval(); 736 737 /* First expand the arguments. */ 738 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 739 setstackmark(&smark); 740 arglist.lastp = &arglist.list; 741 varlist.lastp = &varlist.list; 742 varflag = 1; 743 jp = NULL; 744 do_clearcmdentry = 0; 745 oexitstatus = exitstatus; 746 exitstatus = 0; 747 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 748 if (varflag && isassignment(argp->narg.text)) { 749 expandarg(argp, &varlist, EXP_VARTILDE); 750 continue; 751 } 752 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 753 varflag = 0; 754 } 755 *arglist.lastp = NULL; 756 *varlist.lastp = NULL; 757 expredir(cmd->ncmd.redirect); 758 argc = 0; 759 for (sp = arglist.list ; sp ; sp = sp->next) 760 argc++; 761 /* Add one slot at the beginning for tryexec(). */ 762 argv = stalloc(sizeof (char *) * (argc + 2)); 763 argv++; 764 765 for (sp = arglist.list ; sp ; sp = sp->next) { 766 TRACE(("evalcommand arg: %s\n", sp->text)); 767 *argv++ = sp->text; 768 } 769 *argv = NULL; 770 lastarg = NULL; 771 if (iflag && funcnest == 0 && argc > 0) 772 lastarg = argv[-1]; 773 argv -= argc; 774 775 /* Print the command if xflag is set. */ 776 if (xflag) { 777 char sep = 0; 778 const char *p, *ps4; 779 ps4 = expandstr(ps4val()); 780 out2str(ps4 != NULL ? ps4 : ps4val()); 781 for (sp = varlist.list ; sp ; sp = sp->next) { 782 if (sep != 0) 783 out2c(' '); 784 p = strchr(sp->text, '='); 785 if (p != NULL) { 786 p++; 787 outbin(sp->text, p - sp->text, out2); 788 out2qstr(p); 789 } else 790 out2qstr(sp->text); 791 sep = ' '; 792 } 793 for (sp = arglist.list ; sp ; sp = sp->next) { 794 if (sep != 0) 795 out2c(' '); 796 /* Disambiguate command looking like assignment. */ 797 if (sp == arglist.list && 798 strchr(sp->text, '=') != NULL && 799 strchr(sp->text, '\'') == NULL) { 800 out2c('\''); 801 out2str(sp->text); 802 out2c('\''); 803 } else 804 out2qstr(sp->text); 805 sep = ' '; 806 } 807 out2c('\n'); 808 flushout(&errout); 809 } 810 811 /* Now locate the command. */ 812 if (argc == 0) { 813 /* Variable assignment(s) without command */ 814 cmdentry.cmdtype = CMDBUILTIN; 815 cmdentry.u.index = BLTINCMD; 816 cmdentry.special = 0; 817 } else { 818 static const char PATH[] = "PATH="; 819 int cmd_flags = 0, bltinonly = 0; 820 821 /* 822 * Modify the command lookup path, if a PATH= assignment 823 * is present 824 */ 825 for (sp = varlist.list ; sp ; sp = sp->next) 826 if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0) { 827 path = sp->text + sizeof(PATH) - 1; 828 /* 829 * On `PATH=... command`, we need to make 830 * sure that the command isn't using the 831 * non-updated hash table of the outer PATH 832 * setting and we need to make sure that 833 * the hash table isn't filled with items 834 * from the temporary setting. 835 * 836 * It would be better to forbit using and 837 * updating the table while this command 838 * runs, by the command finding mechanism 839 * is heavily integrated with hash handling, 840 * so we just delete the hash before and after 841 * the command runs. Partly deleting like 842 * changepatch() does doesn't seem worth the 843 * bookinging effort, since most such runs add 844 * directories in front of the new PATH. 845 */ 846 clearcmdentry(); 847 do_clearcmdentry = 1; 848 } 849 850 for (;;) { 851 if (bltinonly) { 852 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 853 if (cmdentry.u.index < 0) { 854 cmdentry.u.index = BLTINCMD; 855 argv--; 856 argc++; 857 break; 858 } 859 } else 860 find_command(argv[0], &cmdentry, cmd_flags, path); 861 /* implement the bltin and command builtins here */ 862 if (cmdentry.cmdtype != CMDBUILTIN) 863 break; 864 if (cmdentry.u.index == BLTINCMD) { 865 if (argc == 1) 866 break; 867 argv++; 868 argc--; 869 bltinonly = 1; 870 } else if (cmdentry.u.index == COMMANDCMD) { 871 if (argc == 1) 872 break; 873 if (!strcmp(argv[1], "-p")) { 874 if (argc == 2) 875 break; 876 if (argv[2][0] == '-') { 877 if (strcmp(argv[2], "--")) 878 break; 879 if (argc == 3) 880 break; 881 argv += 3; 882 argc -= 3; 883 } else { 884 argv += 2; 885 argc -= 2; 886 } 887 path = _PATH_STDPATH; 888 clearcmdentry(); 889 do_clearcmdentry = 1; 890 } else if (!strcmp(argv[1], "--")) { 891 if (argc == 2) 892 break; 893 argv += 2; 894 argc -= 2; 895 } else if (argv[1][0] == '-') 896 break; 897 else { 898 argv++; 899 argc--; 900 } 901 cmd_flags |= DO_NOFUNC; 902 bltinonly = 0; 903 } else 904 break; 905 } 906 /* 907 * Special builtins lose their special properties when 908 * called via 'command'. 909 */ 910 if (cmd_flags & DO_NOFUNC) 911 cmdentry.special = 0; 912 } 913 914 /* Fork off a child process if necessary. */ 915 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 916 && ((flags & EV_EXIT) == 0 || have_traps())) 917 || ((flags & EV_BACKCMD) != 0 918 && (cmdentry.cmdtype != CMDBUILTIN || 919 !safe_builtin(cmdentry.u.index, argc, argv)))) { 920 jp = makejob(cmd, 1); 921 mode = FORK_FG; 922 if (flags & EV_BACKCMD) { 923 mode = FORK_NOJOB; 924 if (pipe(pip) < 0) 925 error("Pipe call failed: %s", strerror(errno)); 926 } 927 if (forkshell(jp, cmd, mode) != 0) 928 goto parent; /* at end of routine */ 929 if (flags & EV_BACKCMD) { 930 FORCEINTON; 931 close(pip[0]); 932 if (pip[1] != 1) { 933 dup2(pip[1], 1); 934 close(pip[1]); 935 } 936 flags &= ~EV_BACKCMD; 937 } 938 flags |= EV_EXIT; 939 } 940 941 /* This is the child process if a fork occurred. */ 942 /* Execute the command. */ 943 if (cmdentry.cmdtype == CMDFUNCTION) { 944 #ifdef DEBUG 945 trputs("Shell function: "); trargs(argv); 946 #endif 947 saveparam = shellparam; 948 shellparam.malloc = 0; 949 shellparam.reset = 1; 950 shellparam.nparam = argc - 1; 951 shellparam.p = argv + 1; 952 shellparam.optnext = NULL; 953 INTOFF; 954 savelocalvars = localvars; 955 localvars = NULL; 956 reffunc(cmdentry.u.func); 957 savehandler = handler; 958 if (setjmp(jmploc.loc)) { 959 freeparam(&shellparam); 960 shellparam = saveparam; 961 popredir(); 962 unreffunc(cmdentry.u.func); 963 poplocalvars(); 964 localvars = savelocalvars; 965 funcnest--; 966 handler = savehandler; 967 longjmp(handler->loc, 1); 968 } 969 handler = &jmploc; 970 funcnest++; 971 redirect(cmd->ncmd.redirect, REDIR_PUSH); 972 INTON; 973 for (sp = varlist.list ; sp ; sp = sp->next) 974 mklocal(sp->text); 975 exitstatus = oexitstatus; 976 evaltree(getfuncnode(cmdentry.u.func), 977 flags & (EV_TESTED | EV_EXIT)); 978 INTOFF; 979 unreffunc(cmdentry.u.func); 980 poplocalvars(); 981 localvars = savelocalvars; 982 freeparam(&shellparam); 983 shellparam = saveparam; 984 handler = savehandler; 985 funcnest--; 986 popredir(); 987 INTON; 988 if (evalskip == SKIPFUNC) { 989 evalskip = 0; 990 skipcount = 0; 991 } 992 if (jp) 993 exitshell(exitstatus); 994 } else if (cmdentry.cmdtype == CMDBUILTIN) { 995 #ifdef DEBUG 996 trputs("builtin command: "); trargs(argv); 997 #endif 998 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 999 if (flags == EV_BACKCMD) { 1000 memout.nleft = 0; 1001 memout.nextc = memout.buf; 1002 memout.bufsize = 64; 1003 mode |= REDIR_BACKQ; 1004 } 1005 savecmdname = commandname; 1006 savetopfile = getcurrentfile(); 1007 cmdenviron = varlist.list; 1008 e = -1; 1009 savehandler = handler; 1010 if (setjmp(jmploc.loc)) { 1011 e = exception; 1012 if (e == EXINT) 1013 exitstatus = SIGINT+128; 1014 else if (e != EXEXIT) 1015 exitstatus = 2; 1016 goto cmddone; 1017 } 1018 handler = &jmploc; 1019 redirect(cmd->ncmd.redirect, mode); 1020 /* 1021 * If there is no command word, redirection errors should 1022 * not be fatal but assignment errors should. 1023 */ 1024 if (argc == 0) 1025 cmdentry.special = 1; 1026 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1027 if (argc > 0) 1028 bltinsetlocale(); 1029 commandname = argv[0]; 1030 argptr = argv + 1; 1031 nextopt_optptr = NULL; /* initialize nextopt */ 1032 builtin_flags = flags; 1033 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1034 flushall(); 1035 cmddone: 1036 if (argc > 0) 1037 bltinunsetlocale(); 1038 cmdenviron = NULL; 1039 out1 = &output; 1040 out2 = &errout; 1041 freestdout(); 1042 handler = savehandler; 1043 commandname = savecmdname; 1044 if (jp) 1045 exitshell(exitstatus); 1046 if (flags == EV_BACKCMD) { 1047 backcmd->buf = memout.buf; 1048 backcmd->nleft = memout.nextc - memout.buf; 1049 memout.buf = NULL; 1050 } 1051 if (cmdentry.u.index != EXECCMD) 1052 popredir(); 1053 if (e != -1) { 1054 if ((e != EXERROR && e != EXEXEC) 1055 || cmdentry.special) 1056 exraise(e); 1057 popfilesupto(savetopfile); 1058 if (flags != EV_BACKCMD) 1059 FORCEINTON; 1060 } 1061 } else { 1062 #ifdef DEBUG 1063 trputs("normal command: "); trargs(argv); 1064 #endif 1065 redirect(cmd->ncmd.redirect, 0); 1066 for (sp = varlist.list ; sp ; sp = sp->next) 1067 setvareq(sp->text, VEXPORT|VSTACK); 1068 envp = environment(); 1069 shellexec(argv, envp, path, cmdentry.u.index); 1070 /*NOTREACHED*/ 1071 } 1072 goto out; 1073 1074 parent: /* parent process gets here (if we forked) */ 1075 if (mode == FORK_FG) { /* argument to fork */ 1076 INTOFF; 1077 exitstatus = waitforjob(jp, &realstatus); 1078 INTON; 1079 if (iflag && loopnest > 0 && WIFSIGNALED(realstatus)) { 1080 evalskip = SKIPBREAK; 1081 skipcount = loopnest; 1082 } 1083 } else if (mode == FORK_NOJOB) { 1084 backcmd->fd = pip[0]; 1085 close(pip[1]); 1086 backcmd->jp = jp; 1087 } 1088 1089 out: 1090 if (lastarg) 1091 setvar("_", lastarg, 0); 1092 if (do_clearcmdentry) 1093 clearcmdentry(); 1094 popstackmark(&smark); 1095 } 1096 1097 1098 1099 /* 1100 * Search for a command. This is called before we fork so that the 1101 * location of the command will be available in the parent as well as 1102 * the child. The check for "goodname" is an overly conservative 1103 * check that the name will not be subject to expansion. 1104 */ 1105 1106 static void 1107 prehash(union node *n) 1108 { 1109 struct cmdentry entry; 1110 1111 if (n && n->type == NCMD && n->ncmd.args) 1112 if (goodname(n->ncmd.args->narg.text)) 1113 find_command(n->ncmd.args->narg.text, &entry, 0, 1114 pathval()); 1115 } 1116 1117 1118 1119 /* 1120 * Builtin commands. Builtin commands whose functions are closely 1121 * tied to evaluation are implemented here. 1122 */ 1123 1124 /* 1125 * No command given, a bltin command with no arguments, or a bltin command 1126 * with an invalid name. 1127 */ 1128 1129 int 1130 bltincmd(int argc, char **argv) 1131 { 1132 if (argc > 1) { 1133 out2fmt_flush("%s: not found\n", argv[1]); 1134 return 127; 1135 } 1136 /* 1137 * Preserve exitstatus of a previous possible redirection 1138 * as POSIX mandates 1139 */ 1140 return exitstatus; 1141 } 1142 1143 1144 /* 1145 * Handle break and continue commands. Break, continue, and return are 1146 * all handled by setting the evalskip flag. The evaluation routines 1147 * above all check this flag, and if it is set they start skipping 1148 * commands rather than executing them. The variable skipcount is 1149 * the number of loops to break/continue, or the number of function 1150 * levels to return. (The latter is always 1.) It should probably 1151 * be an error to break out of more loops than exist, but it isn't 1152 * in the standard shell so we don't make it one here. 1153 */ 1154 1155 int 1156 breakcmd(int argc, char **argv) 1157 { 1158 int n = argc > 1 ? number(argv[1]) : 1; 1159 1160 if (n > loopnest) 1161 n = loopnest; 1162 if (n > 0) { 1163 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1164 skipcount = n; 1165 } 1166 return 0; 1167 } 1168 1169 /* 1170 * The `command' command. 1171 */ 1172 int 1173 commandcmd(int argc, char **argv) 1174 { 1175 const char *path; 1176 int ch; 1177 int cmd = -1; 1178 1179 path = bltinlookup("PATH", 1); 1180 1181 optind = optreset = 1; 1182 opterr = 0; 1183 while ((ch = getopt(argc, argv, "pvV")) != -1) { 1184 switch (ch) { 1185 case 'p': 1186 path = _PATH_STDPATH; 1187 break; 1188 case 'v': 1189 cmd = TYPECMD_SMALLV; 1190 break; 1191 case 'V': 1192 cmd = TYPECMD_BIGV; 1193 break; 1194 case '?': 1195 default: 1196 error("unknown option: -%c", optopt); 1197 } 1198 } 1199 argc -= optind; 1200 argv += optind; 1201 1202 if (cmd != -1) { 1203 if (argc != 1) 1204 error("wrong number of arguments"); 1205 return typecmd_impl(2, argv - 1, cmd, path); 1206 } 1207 if (argc != 0) 1208 error("commandcmd bad call"); 1209 1210 /* 1211 * Do nothing successfully if no command was specified; 1212 * ksh also does this. 1213 */ 1214 return(0); 1215 } 1216 1217 1218 /* 1219 * The return command. 1220 */ 1221 1222 int 1223 returncmd(int argc, char **argv) 1224 { 1225 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1226 1227 if (funcnest) { 1228 evalskip = SKIPFUNC; 1229 skipcount = 1; 1230 } else { 1231 /* skip the rest of the file */ 1232 evalskip = SKIPFILE; 1233 skipcount = 1; 1234 } 1235 return ret; 1236 } 1237 1238 1239 int 1240 falsecmd(int argc __unused, char **argv __unused) 1241 { 1242 return 1; 1243 } 1244 1245 1246 int 1247 truecmd(int argc __unused, char **argv __unused) 1248 { 1249 return 0; 1250 } 1251 1252 1253 int 1254 execcmd(int argc, char **argv) 1255 { 1256 /* 1257 * Because we have historically not supported any options, 1258 * only treat "--" specially. 1259 */ 1260 if (argc > 1 && strcmp(argv[1], "--") == 0) 1261 argc--, argv++; 1262 if (argc > 1) { 1263 struct strlist *sp; 1264 1265 iflag = 0; /* exit on error */ 1266 mflag = 0; 1267 optschanged(); 1268 for (sp = cmdenviron; sp ; sp = sp->next) 1269 setvareq(sp->text, VEXPORT|VSTACK); 1270 shellexec(argv + 1, environment(), pathval(), 0); 1271 1272 } 1273 return 0; 1274 } 1275 1276 1277 int 1278 timescmd(int argc __unused, char **argv __unused) 1279 { 1280 struct rusage ru; 1281 long shumins, shsmins, chumins, chsmins; 1282 double shusecs, shssecs, chusecs, chssecs; 1283 1284 if (getrusage(RUSAGE_SELF, &ru) < 0) 1285 return 1; 1286 shumins = ru.ru_utime.tv_sec / 60; 1287 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1288 shsmins = ru.ru_stime.tv_sec / 60; 1289 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1290 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1291 return 1; 1292 chumins = ru.ru_utime.tv_sec / 60; 1293 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1294 chsmins = ru.ru_stime.tv_sec / 60; 1295 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1296 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1297 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1298 return 0; 1299 } 1300