1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Kenneth Almquist. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <paths.h> 36 #include <signal.h> 37 #include <stdbool.h> 38 #include <stdlib.h> 39 #include <unistd.h> 40 #include <sys/resource.h> 41 #include <errno.h> 42 43 /* 44 * Evaluate a command. 45 */ 46 47 #include "shell.h" 48 #include "nodes.h" 49 #include "syntax.h" 50 #include "expand.h" 51 #include "parser.h" 52 #include "jobs.h" 53 #include "eval.h" 54 #include "builtins.h" 55 #include "options.h" 56 #include "exec.h" 57 #include "redir.h" 58 #include "input.h" 59 #include "output.h" 60 #include "trap.h" 61 #include "var.h" 62 #include "memalloc.h" 63 #include "error.h" 64 #include "show.h" 65 #include "mystring.h" 66 #ifndef NO_HISTORY 67 #include "myhistedit.h" 68 #endif 69 70 71 int evalskip; /* set if we are skipping commands */ 72 int skipcount; /* number of levels to skip */ 73 static int loopnest; /* current loop nesting level */ 74 int funcnest; /* depth of function calls */ 75 static int builtin_flags; /* evalcommand flags for builtins */ 76 77 78 char *commandname; 79 struct arglist *cmdenviron; 80 int exitstatus; /* exit status of last command */ 81 int oexitstatus; /* saved exit status */ 82 83 84 static void evalloop(union node *, int); 85 static void evalfor(union node *, int); 86 static union node *evalcase(union node *); 87 static void evalsubshell(union node *, int); 88 static void evalredir(union node *, int); 89 static void exphere(union node *, struct arglist *); 90 static void expredir(union node *); 91 static void evalpipe(union node *); 92 static int is_valid_fast_cmdsubst(union node *n); 93 static void evalcommand(union node *, int, struct backcmd *); 94 static void prehash(union node *); 95 96 97 /* 98 * Called to reset things after an exception. 99 */ 100 101 void 102 reseteval(void) 103 { 104 evalskip = 0; 105 loopnest = 0; 106 } 107 108 109 /* 110 * The eval command. 111 */ 112 113 int 114 evalcmd(int argc, char **argv) 115 { 116 char *p; 117 char *concat; 118 char **ap; 119 120 if (argc > 1) { 121 p = argv[1]; 122 if (argc > 2) { 123 STARTSTACKSTR(concat); 124 ap = argv + 2; 125 for (;;) { 126 STPUTS(p, concat); 127 if ((p = *ap++) == NULL) 128 break; 129 STPUTC(' ', concat); 130 } 131 STPUTC('\0', concat); 132 p = grabstackstr(concat); 133 } 134 evalstring(p, builtin_flags); 135 } else 136 exitstatus = 0; 137 return exitstatus; 138 } 139 140 141 /* 142 * Execute a command or commands contained in a string. 143 */ 144 145 void 146 evalstring(const char *s, int flags) 147 { 148 union node *n; 149 struct stackmark smark; 150 int flags_exit; 151 int any; 152 153 flags_exit = flags & EV_EXIT; 154 flags &= ~EV_EXIT; 155 any = 0; 156 setstackmark(&smark); 157 setinputstring(s, 1); 158 while ((n = parsecmd(0)) != NEOF) { 159 if (n != NULL && !nflag) { 160 if (flags_exit && preadateof()) 161 evaltree(n, flags | EV_EXIT); 162 else 163 evaltree(n, flags); 164 any = 1; 165 if (evalskip) 166 break; 167 } 168 popstackmark(&smark); 169 setstackmark(&smark); 170 } 171 popfile(); 172 popstackmark(&smark); 173 if (!any) 174 exitstatus = 0; 175 if (flags_exit) 176 exraise(EXEXIT); 177 } 178 179 180 /* 181 * Evaluate a parse tree. The value is left in the global variable 182 * exitstatus. 183 */ 184 185 void 186 evaltree(union node *n, int flags) 187 { 188 int do_etest; 189 union node *next; 190 struct stackmark smark; 191 192 setstackmark(&smark); 193 do_etest = 0; 194 if (n == NULL) { 195 TRACE(("evaltree(NULL) called\n")); 196 exitstatus = 0; 197 goto out; 198 } 199 do { 200 next = NULL; 201 #ifndef NO_HISTORY 202 displayhist = 1; /* show history substitutions done with fc */ 203 #endif 204 TRACE(("evaltree(%p: %d) called\n", (void *)n, n->type)); 205 switch (n->type) { 206 case NSEMI: 207 evaltree(n->nbinary.ch1, flags & ~EV_EXIT); 208 if (evalskip) 209 goto out; 210 next = n->nbinary.ch2; 211 break; 212 case NAND: 213 evaltree(n->nbinary.ch1, EV_TESTED); 214 if (evalskip || exitstatus != 0) { 215 goto out; 216 } 217 next = n->nbinary.ch2; 218 break; 219 case NOR: 220 evaltree(n->nbinary.ch1, EV_TESTED); 221 if (evalskip || exitstatus == 0) 222 goto out; 223 next = n->nbinary.ch2; 224 break; 225 case NREDIR: 226 evalredir(n, flags); 227 break; 228 case NSUBSHELL: 229 evalsubshell(n, flags); 230 do_etest = !(flags & EV_TESTED); 231 break; 232 case NBACKGND: 233 evalsubshell(n, flags); 234 break; 235 case NIF: { 236 evaltree(n->nif.test, EV_TESTED); 237 if (evalskip) 238 goto out; 239 if (exitstatus == 0) 240 next = n->nif.ifpart; 241 else if (n->nif.elsepart) 242 next = n->nif.elsepart; 243 else 244 exitstatus = 0; 245 break; 246 } 247 case NWHILE: 248 case NUNTIL: 249 evalloop(n, flags & ~EV_EXIT); 250 break; 251 case NFOR: 252 evalfor(n, flags & ~EV_EXIT); 253 break; 254 case NCASE: 255 next = evalcase(n); 256 break; 257 case NCLIST: 258 next = n->nclist.body; 259 break; 260 case NCLISTFALLTHRU: 261 if (n->nclist.body) { 262 evaltree(n->nclist.body, flags & ~EV_EXIT); 263 if (evalskip) 264 goto out; 265 } 266 next = n->nclist.next; 267 break; 268 case NDEFUN: 269 defun(n->narg.text, n->narg.next); 270 exitstatus = 0; 271 break; 272 case NNOT: 273 evaltree(n->nnot.com, EV_TESTED); 274 if (evalskip) 275 goto out; 276 exitstatus = !exitstatus; 277 break; 278 279 case NPIPE: 280 evalpipe(n); 281 do_etest = !(flags & EV_TESTED); 282 break; 283 case NCMD: 284 evalcommand(n, flags, (struct backcmd *)NULL); 285 do_etest = !(flags & EV_TESTED); 286 break; 287 default: 288 out1fmt("Node type = %d\n", n->type); 289 flushout(&output); 290 break; 291 } 292 n = next; 293 popstackmark(&smark); 294 setstackmark(&smark); 295 } while (n != NULL); 296 out: 297 popstackmark(&smark); 298 if (pendingsig) 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 if (!evalskip) 316 evaltree(n->nbinary.ch1, EV_TESTED); 317 if (evalskip) { 318 if (evalskip == SKIPCONT && --skipcount <= 0) { 319 evalskip = 0; 320 continue; 321 } 322 if (evalskip == SKIPBREAK && --skipcount <= 0) 323 evalskip = 0; 324 if (evalskip == SKIPRETURN) 325 status = exitstatus; 326 break; 327 } 328 if (n->type == NWHILE) { 329 if (exitstatus != 0) 330 break; 331 } else { 332 if (exitstatus == 0) 333 break; 334 } 335 evaltree(n->nbinary.ch2, flags); 336 status = exitstatus; 337 } 338 loopnest--; 339 exitstatus = status; 340 } 341 342 343 344 static void 345 evalfor(union node *n, int flags) 346 { 347 struct arglist arglist; 348 union node *argp; 349 int i; 350 int status; 351 352 emptyarglist(&arglist); 353 for (argp = n->nfor.args ; argp ; argp = argp->narg.next) { 354 oexitstatus = exitstatus; 355 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 356 } 357 358 loopnest++; 359 status = 0; 360 for (i = 0; i < arglist.count; i++) { 361 setvar(n->nfor.var, arglist.args[i], 0); 362 evaltree(n->nfor.body, flags); 363 status = exitstatus; 364 if (evalskip) { 365 if (evalskip == SKIPCONT && --skipcount <= 0) { 366 evalskip = 0; 367 continue; 368 } 369 if (evalskip == SKIPBREAK && --skipcount <= 0) 370 evalskip = 0; 371 break; 372 } 373 } 374 loopnest--; 375 exitstatus = status; 376 } 377 378 379 /* 380 * Evaluate a case statement, returning the selected tree. 381 * 382 * The exit status needs care to get right. 383 */ 384 385 static union node * 386 evalcase(union node *n) 387 { 388 union node *cp; 389 union node *patp; 390 struct arglist arglist; 391 392 emptyarglist(&arglist); 393 oexitstatus = exitstatus; 394 expandarg(n->ncase.expr, &arglist, EXP_TILDE); 395 for (cp = n->ncase.cases ; cp ; cp = cp->nclist.next) { 396 for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) { 397 if (casematch(patp, arglist.args[0])) { 398 while (cp->nclist.next && 399 cp->type == NCLISTFALLTHRU && 400 cp->nclist.body == NULL) 401 cp = cp->nclist.next; 402 if (cp->nclist.next && 403 cp->type == NCLISTFALLTHRU) 404 return (cp); 405 if (cp->nclist.body == NULL) 406 exitstatus = 0; 407 return (cp->nclist.body); 408 } 409 } 410 } 411 exitstatus = 0; 412 return (NULL); 413 } 414 415 416 417 /* 418 * Kick off a subshell to evaluate a tree. 419 */ 420 421 static void 422 evalsubshell(union node *n, int flags) 423 { 424 struct job *jp; 425 int backgnd = (n->type == NBACKGND); 426 427 oexitstatus = exitstatus; 428 expredir(n->nredir.redirect); 429 if ((!backgnd && flags & EV_EXIT && !have_traps()) || 430 forkshell(jp = makejob(n, 1), n, backgnd) == 0) { 431 if (backgnd) 432 flags &=~ EV_TESTED; 433 redirect(n->nredir.redirect, 0); 434 evaltree(n->nredir.n, flags | EV_EXIT); /* never returns */ 435 } else if (! backgnd) { 436 INTOFF; 437 exitstatus = waitforjob(jp, (int *)NULL); 438 INTON; 439 } else 440 exitstatus = 0; 441 } 442 443 444 /* 445 * Evaluate a redirected compound command. 446 */ 447 448 static void 449 evalredir(union node *n, int flags) 450 { 451 struct jmploc jmploc; 452 struct jmploc *savehandler; 453 volatile int in_redirect = 1; 454 455 oexitstatus = exitstatus; 456 expredir(n->nredir.redirect); 457 savehandler = handler; 458 if (setjmp(jmploc.loc)) { 459 int e; 460 461 handler = savehandler; 462 e = exception; 463 popredir(); 464 if (e == EXERROR && in_redirect) { 465 FORCEINTON; 466 return; 467 } 468 longjmp(handler->loc, 1); 469 } else { 470 INTOFF; 471 handler = &jmploc; 472 redirect(n->nredir.redirect, REDIR_PUSH); 473 in_redirect = 0; 474 INTON; 475 evaltree(n->nredir.n, flags); 476 } 477 INTOFF; 478 handler = savehandler; 479 popredir(); 480 INTON; 481 } 482 483 484 static void 485 exphere(union node *redir, struct arglist *fn) 486 { 487 struct jmploc jmploc; 488 struct jmploc *savehandler; 489 struct localvar *savelocalvars; 490 int need_longjmp = 0; 491 unsigned char saveoptreset; 492 493 redir->nhere.expdoc = ""; 494 savelocalvars = localvars; 495 localvars = NULL; 496 saveoptreset = shellparam.reset; 497 forcelocal++; 498 savehandler = handler; 499 if (setjmp(jmploc.loc)) 500 need_longjmp = exception != EXERROR; 501 else { 502 handler = &jmploc; 503 expandarg(redir->nhere.doc, fn, 0); 504 redir->nhere.expdoc = fn->args[0]; 505 INTOFF; 506 } 507 handler = savehandler; 508 forcelocal--; 509 poplocalvars(); 510 localvars = savelocalvars; 511 shellparam.reset = saveoptreset; 512 if (need_longjmp) 513 longjmp(handler->loc, 1); 514 INTON; 515 } 516 517 518 /* 519 * Compute the names of the files in a redirection list. 520 */ 521 522 static void 523 expredir(union node *n) 524 { 525 union node *redir; 526 527 for (redir = n ; redir ; redir = redir->nfile.next) { 528 struct arglist fn; 529 emptyarglist(&fn); 530 switch (redir->type) { 531 case NFROM: 532 case NTO: 533 case NFROMTO: 534 case NAPPEND: 535 case NCLOBBER: 536 expandarg(redir->nfile.fname, &fn, EXP_TILDE); 537 redir->nfile.expfname = fn.args[0]; 538 break; 539 case NFROMFD: 540 case NTOFD: 541 if (redir->ndup.vname) { 542 expandarg(redir->ndup.vname, &fn, EXP_TILDE); 543 fixredir(redir, fn.args[0], 1); 544 } 545 break; 546 case NXHERE: 547 exphere(redir, &fn); 548 break; 549 } 550 } 551 } 552 553 554 555 /* 556 * Evaluate a pipeline. All the processes in the pipeline are children 557 * of the process creating the pipeline. (This differs from some versions 558 * of the shell, which make the last process in a pipeline the parent 559 * of all the rest.) 560 */ 561 562 static void 563 evalpipe(union node *n) 564 { 565 struct job *jp; 566 struct nodelist *lp; 567 int pipelen; 568 int prevfd; 569 int pip[2]; 570 571 TRACE(("evalpipe(%p) called\n", (void *)n)); 572 pipelen = 0; 573 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) 574 pipelen++; 575 INTOFF; 576 jp = makejob(n, pipelen); 577 prevfd = -1; 578 for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { 579 prehash(lp->n); 580 pip[1] = -1; 581 if (lp->next) { 582 if (pipe(pip) < 0) { 583 if (prevfd >= 0) 584 close(prevfd); 585 error("Pipe call failed: %s", strerror(errno)); 586 } 587 } 588 if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) { 589 INTON; 590 if (prevfd > 0) { 591 dup2(prevfd, 0); 592 close(prevfd); 593 } 594 if (pip[1] >= 0) { 595 if (!(prevfd >= 0 && pip[0] == 0)) 596 close(pip[0]); 597 if (pip[1] != 1) { 598 dup2(pip[1], 1); 599 close(pip[1]); 600 } 601 } 602 evaltree(lp->n, EV_EXIT); 603 } 604 if (prevfd >= 0) 605 close(prevfd); 606 prevfd = pip[0]; 607 if (pip[1] != -1) 608 close(pip[1]); 609 } 610 INTON; 611 if (n->npipe.backgnd == 0) { 612 INTOFF; 613 exitstatus = waitforjob(jp, (int *)NULL); 614 TRACE(("evalpipe: job done exit status %d\n", exitstatus)); 615 INTON; 616 } else 617 exitstatus = 0; 618 } 619 620 621 622 static int 623 is_valid_fast_cmdsubst(union node *n) 624 { 625 626 return (n->type == NCMD); 627 } 628 629 /* 630 * Execute a command inside back quotes. If it's a builtin command, we 631 * want to save its output in a block obtained from malloc. Otherwise 632 * we fork off a subprocess and get the output of the command via a pipe. 633 * Should be called with interrupts off. 634 */ 635 636 void 637 evalbackcmd(union node *n, struct backcmd *result) 638 { 639 int pip[2]; 640 struct job *jp; 641 struct stackmark smark; 642 struct jmploc jmploc; 643 struct jmploc *savehandler; 644 struct localvar *savelocalvars; 645 unsigned char saveoptreset; 646 647 result->fd = -1; 648 result->buf = NULL; 649 result->nleft = 0; 650 result->jp = NULL; 651 if (n == NULL) { 652 exitstatus = 0; 653 return; 654 } 655 setstackmark(&smark); 656 exitstatus = oexitstatus; 657 if (is_valid_fast_cmdsubst(n)) { 658 savelocalvars = localvars; 659 localvars = NULL; 660 saveoptreset = shellparam.reset; 661 forcelocal++; 662 savehandler = handler; 663 if (setjmp(jmploc.loc)) { 664 if (exception == EXERROR) 665 /* nothing */; 666 else if (exception != 0) { 667 handler = savehandler; 668 forcelocal--; 669 poplocalvars(); 670 localvars = savelocalvars; 671 shellparam.reset = saveoptreset; 672 longjmp(handler->loc, 1); 673 } 674 } else { 675 handler = &jmploc; 676 evalcommand(n, EV_BACKCMD, result); 677 } 678 handler = savehandler; 679 forcelocal--; 680 poplocalvars(); 681 localvars = savelocalvars; 682 shellparam.reset = saveoptreset; 683 } else { 684 if (pipe(pip) < 0) 685 error("Pipe call failed: %s", strerror(errno)); 686 jp = makejob(n, 1); 687 if (forkshell(jp, n, FORK_NOJOB) == 0) { 688 FORCEINTON; 689 close(pip[0]); 690 if (pip[1] != 1) { 691 dup2(pip[1], 1); 692 close(pip[1]); 693 } 694 evaltree(n, EV_EXIT); 695 } 696 close(pip[1]); 697 result->fd = pip[0]; 698 result->jp = jp; 699 } 700 popstackmark(&smark); 701 TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n", 702 result->fd, result->buf, result->nleft, result->jp)); 703 } 704 705 static int 706 mustexpandto(const char *argtext, const char *mask) 707 { 708 for (;;) { 709 if (*argtext == CTLQUOTEMARK || *argtext == CTLQUOTEEND) { 710 argtext++; 711 continue; 712 } 713 if (*argtext == CTLESC) 714 argtext++; 715 else if (BASESYNTAX[(int)*argtext] == CCTL) 716 return (0); 717 if (*argtext != *mask) 718 return (0); 719 if (*argtext == '\0') 720 return (1); 721 argtext++; 722 mask++; 723 } 724 } 725 726 static int 727 isdeclarationcmd(struct narg *arg) 728 { 729 int have_command = 0; 730 731 if (arg == NULL) 732 return (0); 733 while (mustexpandto(arg->text, "command")) { 734 have_command = 1; 735 arg = &arg->next->narg; 736 if (arg == NULL) 737 return (0); 738 /* 739 * To also allow "command -p" and "command --" as part of 740 * a declaration command, add code here. 741 * We do not do this, as ksh does not do it either and it 742 * is not required by POSIX. 743 */ 744 } 745 return (mustexpandto(arg->text, "export") || 746 mustexpandto(arg->text, "readonly") || 747 (mustexpandto(arg->text, "local") && 748 (have_command || !isfunc("local")))); 749 } 750 751 static void 752 xtracecommand(struct arglist *varlist, int argc, char **argv) 753 { 754 char sep = 0; 755 const char *text, *p, *ps4; 756 int i; 757 758 ps4 = expandstr(ps4val()); 759 out2str(ps4 != NULL ? ps4 : ps4val()); 760 for (i = 0; i < varlist->count; i++) { 761 text = varlist->args[i]; 762 if (sep != 0) 763 out2c(' '); 764 p = strchr(text, '='); 765 if (p != NULL) { 766 p++; 767 outbin(text, p - text, out2); 768 out2qstr(p); 769 } else 770 out2qstr(text); 771 sep = ' '; 772 } 773 for (i = 0; i < argc; i++) { 774 text = argv[i]; 775 if (sep != 0) 776 out2c(' '); 777 out2qstr(text); 778 sep = ' '; 779 } 780 out2c('\n'); 781 flushout(&errout); 782 } 783 784 /* 785 * Check if a builtin can safely be executed in the same process, 786 * even though it should be in a subshell (command substitution). 787 * Note that jobid, jobs, times and trap can show information not 788 * available in a child process; this is deliberate. 789 * The arguments should already have been expanded. 790 */ 791 static int 792 safe_builtin(int idx, int argc, char **argv) 793 { 794 /* Generated from builtins.def. */ 795 if (safe_builtin_always(idx)) 796 return (1); 797 if (idx == EXPORTCMD || idx == TRAPCMD || idx == ULIMITCMD || 798 idx == UMASKCMD) 799 return (argc <= 1 || (argc == 2 && argv[1][0] == '-')); 800 if (idx == SETCMD) 801 return (argc <= 1 || (argc == 2 && (argv[1][0] == '-' || 802 argv[1][0] == '+') && argv[1][1] == 'o' && 803 argv[1][2] == '\0')); 804 return (0); 805 } 806 807 /* 808 * Perform redirections, then execute a simple command with vfork. 809 * This cannot be used for command substitutions for two reasons: 810 * - Redirections might cause the error message for later redirections or for 811 * an unknown command to be sent to the pipe (to be substituted), and this 812 * might cause a deadlock if the message is too long. 813 * - The assignment of the pipe needs to come before instead of after the 814 * redirections. 815 */ 816 static bool 817 redirected_vforkexecshell(struct job *jp, union node *redir, char **argv, 818 char **envp, const char *path, int idx) 819 { 820 struct jmploc jmploc; 821 struct jmploc *savehandler; 822 volatile int in_redirect = 1; 823 824 savehandler = handler; 825 if (setjmp(jmploc.loc)) { 826 int e; 827 828 handler = savehandler; 829 e = exception; 830 popredir(); 831 if (e == EXERROR && in_redirect) { 832 FORCEINTON; 833 return false; 834 } 835 longjmp(handler->loc, 1); 836 } else { 837 INTOFF; 838 handler = &jmploc; 839 redirect(redir, REDIR_PUSH); 840 in_redirect = 0; 841 INTON; 842 vforkexecshell(jp, argv, envp, path, idx, NULL); 843 } 844 INTOFF; 845 handler = savehandler; 846 popredir(); 847 INTON; 848 return true; 849 } 850 851 /* 852 * Execute a simple command. 853 * Note: This may or may not return if (flags & EV_EXIT). 854 */ 855 856 static void 857 evalcommand(union node *cmd, int flags, struct backcmd *backcmd) 858 { 859 union node *argp; 860 struct arglist arglist; 861 struct arglist varlist; 862 char **argv; 863 int argc; 864 char **envp; 865 int varflag; 866 int mode; 867 int pip[2]; 868 struct cmdentry cmdentry; 869 struct job *jp; 870 struct jmploc jmploc; 871 struct jmploc *savehandler; 872 char *savecmdname; 873 struct shparam saveparam; 874 struct localvar *savelocalvars; 875 struct parsefile *savetopfile; 876 volatile int e; 877 char *lastarg; 878 int signaled; 879 int do_clearcmdentry; 880 const char *path = pathval(); 881 int i; 882 883 /* First expand the arguments. */ 884 TRACE(("evalcommand(%p, %d) called\n", (void *)cmd, flags)); 885 emptyarglist(&arglist); 886 emptyarglist(&varlist); 887 varflag = 1; 888 jp = NULL; 889 do_clearcmdentry = 0; 890 oexitstatus = exitstatus; 891 exitstatus = 0; 892 /* Add one slot at the beginning for tryexec(). */ 893 appendarglist(&arglist, nullstr); 894 for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) { 895 if (varflag && isassignment(argp->narg.text)) { 896 expandarg(argp, varflag == 1 ? &varlist : &arglist, 897 EXP_VARTILDE); 898 continue; 899 } else if (varflag == 1) 900 varflag = isdeclarationcmd(&argp->narg) ? 2 : 0; 901 expandarg(argp, &arglist, EXP_FULL | EXP_TILDE); 902 } 903 appendarglist(&arglist, nullstr); 904 expredir(cmd->ncmd.redirect); 905 argc = arglist.count - 2; 906 argv = &arglist.args[1]; 907 908 argv[argc] = NULL; 909 lastarg = NULL; 910 if (iflag && funcnest == 0 && argc > 0) 911 lastarg = argv[argc - 1]; 912 913 /* Print the command if xflag is set. */ 914 if (xflag) 915 xtracecommand(&varlist, argc, argv); 916 917 /* Now locate the command. */ 918 if (argc == 0) { 919 /* Variable assignment(s) without command */ 920 cmdentry.cmdtype = CMDBUILTIN; 921 cmdentry.u.index = BLTINCMD; 922 cmdentry.special = 0; 923 } else { 924 static const char PATH[] = "PATH="; 925 int cmd_flags = 0, bltinonly = 0; 926 927 /* 928 * Modify the command lookup path, if a PATH= assignment 929 * is present 930 */ 931 for (i = 0; i < varlist.count; i++) 932 if (strncmp(varlist.args[i], PATH, sizeof(PATH) - 1) == 0) { 933 path = varlist.args[i] + sizeof(PATH) - 1; 934 /* 935 * On `PATH=... command`, we need to make 936 * sure that the command isn't using the 937 * non-updated hash table of the outer PATH 938 * setting and we need to make sure that 939 * the hash table isn't filled with items 940 * from the temporary setting. 941 * 942 * It would be better to forbid using and 943 * updating the table while this command 944 * runs, by the command finding mechanism 945 * is heavily integrated with hash handling, 946 * so we just delete the hash before and after 947 * the command runs. Partly deleting like 948 * changepatch() does doesn't seem worth the 949 * booking effort, since most such runs add 950 * directories in front of the new PATH. 951 */ 952 clearcmdentry(); 953 do_clearcmdentry = 1; 954 } 955 956 for (;;) { 957 if (bltinonly) { 958 cmdentry.u.index = find_builtin(*argv, &cmdentry.special); 959 if (cmdentry.u.index < 0) { 960 cmdentry.u.index = BLTINCMD; 961 argv--; 962 argc++; 963 break; 964 } 965 } else 966 find_command(argv[0], &cmdentry, cmd_flags, path); 967 /* implement the bltin and command builtins here */ 968 if (cmdentry.cmdtype != CMDBUILTIN) 969 break; 970 if (cmdentry.u.index == BLTINCMD) { 971 if (argc == 1) 972 break; 973 argv++; 974 argc--; 975 bltinonly = 1; 976 } else if (cmdentry.u.index == COMMANDCMD) { 977 if (argc == 1) 978 break; 979 if (!strcmp(argv[1], "-p")) { 980 if (argc == 2) 981 break; 982 if (argv[2][0] == '-') { 983 if (strcmp(argv[2], "--")) 984 break; 985 if (argc == 3) 986 break; 987 argv += 3; 988 argc -= 3; 989 } else { 990 argv += 2; 991 argc -= 2; 992 } 993 path = _PATH_STDPATH; 994 clearcmdentry(); 995 do_clearcmdentry = 1; 996 } else if (!strcmp(argv[1], "--")) { 997 if (argc == 2) 998 break; 999 argv += 2; 1000 argc -= 2; 1001 } else if (argv[1][0] == '-') 1002 break; 1003 else { 1004 argv++; 1005 argc--; 1006 } 1007 cmd_flags |= DO_NOFUNC; 1008 bltinonly = 0; 1009 } else 1010 break; 1011 } 1012 /* 1013 * Special builtins lose their special properties when 1014 * called via 'command'. 1015 */ 1016 if (cmd_flags & DO_NOFUNC) 1017 cmdentry.special = 0; 1018 } 1019 1020 /* Fork off a child process if necessary. */ 1021 if (((cmdentry.cmdtype == CMDNORMAL || cmdentry.cmdtype == CMDUNKNOWN) 1022 && ((flags & EV_EXIT) == 0 || have_traps())) 1023 || ((flags & EV_BACKCMD) != 0 1024 && (cmdentry.cmdtype != CMDBUILTIN || 1025 !safe_builtin(cmdentry.u.index, argc, argv)))) { 1026 jp = makejob(cmd, 1); 1027 mode = FORK_FG; 1028 if (flags & EV_BACKCMD) { 1029 mode = FORK_NOJOB; 1030 if (pipe(pip) < 0) 1031 error("Pipe call failed: %s", strerror(errno)); 1032 } 1033 if (cmdentry.cmdtype == CMDNORMAL && 1034 (cmd->ncmd.redirect == NULL || (flags & EV_BACKCMD) == 0) && 1035 varlist.count == 0 && 1036 (mode == FORK_FG || mode == FORK_NOJOB) && 1037 !disvforkset() && !iflag && !mflag) { 1038 if (cmd->ncmd.redirect != NULL) { 1039 if (redirected_vforkexecshell(jp, 1040 cmd->ncmd.redirect, 1041 argv, environment(), path, 1042 cmdentry.u.index)) 1043 goto parent; 1044 else 1045 goto out; 1046 } else 1047 vforkexecshell(jp, argv, environment(), path, 1048 cmdentry.u.index, 1049 flags & EV_BACKCMD ? pip : NULL); 1050 goto parent; 1051 } 1052 if (forkshell(jp, cmd, mode) != 0) 1053 goto parent; /* at end of routine */ 1054 if (flags & EV_BACKCMD) { 1055 FORCEINTON; 1056 close(pip[0]); 1057 if (pip[1] != 1) { 1058 dup2(pip[1], 1); 1059 close(pip[1]); 1060 } 1061 flags &= ~EV_BACKCMD; 1062 } 1063 flags |= EV_EXIT; 1064 } 1065 1066 /* This is the child process if a fork occurred. */ 1067 /* Execute the command. */ 1068 if (cmdentry.cmdtype == CMDFUNCTION) { 1069 #ifdef DEBUG 1070 trputs("Shell function: "); trargs(argv); 1071 #endif 1072 saveparam = shellparam; 1073 shellparam.malloc = 0; 1074 shellparam.reset = 1; 1075 shellparam.nparam = argc - 1; 1076 shellparam.p = argv + 1; 1077 shellparam.optp = NULL; 1078 shellparam.optnext = NULL; 1079 INTOFF; 1080 savelocalvars = localvars; 1081 localvars = NULL; 1082 reffunc(cmdentry.u.func); 1083 savehandler = handler; 1084 if (setjmp(jmploc.loc)) { 1085 popredir(); 1086 unreffunc(cmdentry.u.func); 1087 poplocalvars(); 1088 localvars = savelocalvars; 1089 freeparam(&shellparam); 1090 shellparam = saveparam; 1091 funcnest--; 1092 handler = savehandler; 1093 longjmp(handler->loc, 1); 1094 } 1095 handler = &jmploc; 1096 funcnest++; 1097 redirect(cmd->ncmd.redirect, REDIR_PUSH); 1098 INTON; 1099 for (i = 0; i < varlist.count; i++) 1100 mklocal(varlist.args[i]); 1101 exitstatus = oexitstatus; 1102 evaltree(getfuncnode(cmdentry.u.func), 1103 flags & (EV_TESTED | EV_EXIT)); 1104 INTOFF; 1105 unreffunc(cmdentry.u.func); 1106 poplocalvars(); 1107 localvars = savelocalvars; 1108 freeparam(&shellparam); 1109 shellparam = saveparam; 1110 handler = savehandler; 1111 funcnest--; 1112 popredir(); 1113 INTON; 1114 if (evalskip == SKIPRETURN) { 1115 evalskip = 0; 1116 skipcount = 0; 1117 } 1118 if (jp) 1119 exitshell(exitstatus); 1120 } else if (cmdentry.cmdtype == CMDBUILTIN) { 1121 #ifdef DEBUG 1122 trputs("builtin command: "); trargs(argv); 1123 #endif 1124 mode = (cmdentry.u.index == EXECCMD)? 0 : REDIR_PUSH; 1125 if (flags == EV_BACKCMD) { 1126 memout.nextc = memout.buf; 1127 mode |= REDIR_BACKQ; 1128 } 1129 savecmdname = commandname; 1130 savetopfile = getcurrentfile(); 1131 cmdenviron = &varlist; 1132 e = -1; 1133 savehandler = handler; 1134 if (setjmp(jmploc.loc)) { 1135 e = exception; 1136 if (e == EXINT) 1137 exitstatus = SIGINT+128; 1138 goto cmddone; 1139 } 1140 handler = &jmploc; 1141 redirect(cmd->ncmd.redirect, mode); 1142 outclearerror(out1); 1143 /* 1144 * If there is no command word, redirection errors should 1145 * not be fatal but assignment errors should. 1146 */ 1147 if (argc == 0) 1148 cmdentry.special = 1; 1149 listsetvar(cmdenviron, cmdentry.special ? 0 : VNOSET); 1150 if (argc > 0) 1151 bltinsetlocale(); 1152 commandname = argv[0]; 1153 argptr = argv + 1; 1154 nextopt_optptr = NULL; /* initialize nextopt */ 1155 builtin_flags = flags; 1156 exitstatus = (*builtinfunc[cmdentry.u.index])(argc, argv); 1157 flushall(); 1158 if (outiserror(out1)) { 1159 warning("write error on stdout"); 1160 if (exitstatus == 0 || exitstatus == 1) 1161 exitstatus = 2; 1162 } 1163 cmddone: 1164 if (argc > 0) 1165 bltinunsetlocale(); 1166 cmdenviron = NULL; 1167 out1 = &output; 1168 out2 = &errout; 1169 freestdout(); 1170 handler = savehandler; 1171 commandname = savecmdname; 1172 if (jp) 1173 exitshell(exitstatus); 1174 if (flags == EV_BACKCMD) { 1175 backcmd->buf = memout.buf; 1176 backcmd->nleft = memout.buf != NULL ? 1177 memout.nextc - memout.buf : 0; 1178 memout.buf = NULL; 1179 memout.nextc = NULL; 1180 memout.bufend = NULL; 1181 memout.bufsize = 64; 1182 } 1183 if (cmdentry.u.index != EXECCMD) 1184 popredir(); 1185 if (e != -1) { 1186 if (e != EXERROR || cmdentry.special) 1187 exraise(e); 1188 popfilesupto(savetopfile); 1189 if (flags != EV_BACKCMD) 1190 FORCEINTON; 1191 } 1192 } else { 1193 #ifdef DEBUG 1194 trputs("normal command: "); trargs(argv); 1195 #endif 1196 redirect(cmd->ncmd.redirect, 0); 1197 for (i = 0; i < varlist.count; i++) 1198 setvareq(varlist.args[i], VEXPORT|VSTACK); 1199 envp = environment(); 1200 shellexec(argv, envp, path, cmdentry.u.index); 1201 /*NOTREACHED*/ 1202 } 1203 goto out; 1204 1205 parent: /* parent process gets here (if we forked) */ 1206 if (mode == FORK_FG) { /* argument to fork */ 1207 INTOFF; 1208 exitstatus = waitforjob(jp, &signaled); 1209 INTON; 1210 if (iflag && loopnest > 0 && signaled) { 1211 evalskip = SKIPBREAK; 1212 skipcount = loopnest; 1213 } 1214 } else if (mode == FORK_NOJOB) { 1215 backcmd->fd = pip[0]; 1216 close(pip[1]); 1217 backcmd->jp = jp; 1218 } 1219 1220 out: 1221 if (lastarg) 1222 setvar("_", lastarg, 0); 1223 if (do_clearcmdentry) 1224 clearcmdentry(); 1225 } 1226 1227 1228 1229 /* 1230 * Search for a command. This is called before we fork so that the 1231 * location of the command will be available in the parent as well as 1232 * the child. The check for "goodname" is an overly conservative 1233 * check that the name will not be subject to expansion. 1234 */ 1235 1236 static void 1237 prehash(union node *n) 1238 { 1239 struct cmdentry entry; 1240 1241 if (n && n->type == NCMD && n->ncmd.args) 1242 if (goodname(n->ncmd.args->narg.text)) 1243 find_command(n->ncmd.args->narg.text, &entry, 0, 1244 pathval()); 1245 } 1246 1247 1248 1249 /* 1250 * Builtin commands. Builtin commands whose functions are closely 1251 * tied to evaluation are implemented here. 1252 */ 1253 1254 /* 1255 * No command given, a bltin command with no arguments, or a bltin command 1256 * with an invalid name. 1257 */ 1258 1259 int 1260 bltincmd(int argc, char **argv) 1261 { 1262 if (argc > 1) { 1263 out2fmt_flush("%s: not found\n", argv[1]); 1264 return 127; 1265 } 1266 /* 1267 * Preserve exitstatus of a previous possible command substitution 1268 * as POSIX mandates 1269 */ 1270 return exitstatus; 1271 } 1272 1273 1274 /* 1275 * Handle break and continue commands. Break, continue, and return are 1276 * all handled by setting the evalskip flag. The evaluation routines 1277 * above all check this flag, and if it is set they start skipping 1278 * commands rather than executing them. The variable skipcount is 1279 * the number of loops to break/continue, or the number of function 1280 * levels to return. (The latter is always 1.) It should probably 1281 * be an error to break out of more loops than exist, but it isn't 1282 * in the standard shell so we don't make it one here. 1283 */ 1284 1285 int 1286 breakcmd(int argc, char **argv) 1287 { 1288 long n; 1289 char *end; 1290 1291 if (argc > 1) { 1292 /* Allow arbitrarily large numbers. */ 1293 n = strtol(argv[1], &end, 10); 1294 if (!is_digit(argv[1][0]) || *end != '\0') 1295 error("Illegal number: %s", argv[1]); 1296 } else 1297 n = 1; 1298 if (n > loopnest) 1299 n = loopnest; 1300 if (n > 0) { 1301 evalskip = (**argv == 'c')? SKIPCONT : SKIPBREAK; 1302 skipcount = n; 1303 } 1304 return 0; 1305 } 1306 1307 /* 1308 * The `command' command. 1309 */ 1310 int 1311 commandcmd(int argc __unused, char **argv __unused) 1312 { 1313 const char *path; 1314 int ch; 1315 int cmd = -1; 1316 1317 path = bltinlookup("PATH", 1); 1318 1319 while ((ch = nextopt("pvV")) != '\0') { 1320 switch (ch) { 1321 case 'p': 1322 path = _PATH_STDPATH; 1323 break; 1324 case 'v': 1325 cmd = TYPECMD_SMALLV; 1326 break; 1327 case 'V': 1328 cmd = TYPECMD_BIGV; 1329 break; 1330 } 1331 } 1332 1333 if (cmd != -1) { 1334 if (*argptr == NULL || argptr[1] != NULL) 1335 error("wrong number of arguments"); 1336 return typecmd_impl(2, argptr - 1, cmd, path); 1337 } 1338 if (*argptr != NULL) 1339 error("commandcmd bad call"); 1340 1341 /* 1342 * Do nothing successfully if no command was specified; 1343 * ksh also does this. 1344 */ 1345 return 0; 1346 } 1347 1348 1349 /* 1350 * The return command. 1351 */ 1352 1353 int 1354 returncmd(int argc, char **argv) 1355 { 1356 int ret = argc > 1 ? number(argv[1]) : oexitstatus; 1357 1358 evalskip = SKIPRETURN; 1359 skipcount = 1; 1360 return ret; 1361 } 1362 1363 1364 int 1365 falsecmd(int argc __unused, char **argv __unused) 1366 { 1367 return 1; 1368 } 1369 1370 1371 int 1372 truecmd(int argc __unused, char **argv __unused) 1373 { 1374 return 0; 1375 } 1376 1377 1378 int 1379 execcmd(int argc, char **argv) 1380 { 1381 int i; 1382 1383 /* 1384 * Because we have historically not supported any options, 1385 * only treat "--" specially. 1386 */ 1387 if (argc > 1 && strcmp(argv[1], "--") == 0) 1388 argc--, argv++; 1389 if (argc > 1) { 1390 iflag = 0; /* exit on error */ 1391 mflag = 0; 1392 optschanged(); 1393 for (i = 0; i < cmdenviron->count; i++) 1394 setvareq(cmdenviron->args[i], VEXPORT|VSTACK); 1395 shellexec(argv + 1, environment(), pathval(), 0); 1396 1397 } 1398 return 0; 1399 } 1400 1401 1402 int 1403 timescmd(int argc __unused, char **argv __unused) 1404 { 1405 struct rusage ru; 1406 long shumins, shsmins, chumins, chsmins; 1407 double shusecs, shssecs, chusecs, chssecs; 1408 1409 if (getrusage(RUSAGE_SELF, &ru) < 0) 1410 return 1; 1411 shumins = ru.ru_utime.tv_sec / 60; 1412 shusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1413 shsmins = ru.ru_stime.tv_sec / 60; 1414 shssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1415 if (getrusage(RUSAGE_CHILDREN, &ru) < 0) 1416 return 1; 1417 chumins = ru.ru_utime.tv_sec / 60; 1418 chusecs = ru.ru_utime.tv_sec % 60 + ru.ru_utime.tv_usec / 1000000.; 1419 chsmins = ru.ru_stime.tv_sec / 60; 1420 chssecs = ru.ru_stime.tv_sec % 60 + ru.ru_stime.tv_usec / 1000000.; 1421 out1fmt("%ldm%.3fs %ldm%.3fs\n%ldm%.3fs %ldm%.3fs\n", shumins, 1422 shusecs, shsmins, shssecs, chumins, chusecs, chsmins, chssecs); 1423 return 0; 1424 } 1425