1 /*- 2 * Copyright (c) 1991 The Regents of the University of California. 3 * 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 37 #ifndef lint 38 static char sccsid[] = "@(#)exec.c 5.2 (Berkeley) 3/13/91"; 39 #endif /* not lint */ 40 41 /* 42 * When commands are first encountered, they are entered in a hash table. 43 * This ensures that a full path search will not have to be done for them 44 * on each invocation. 45 * 46 * We should investigate converting to a linear search, even though that 47 * would make the command name "hash" a misnomer. 48 */ 49 50 #include "shell.h" 51 #include "main.h" 52 #include "nodes.h" 53 #include "parser.h" 54 #include "redir.h" 55 #include "eval.h" 56 #include "exec.h" 57 #include "builtins.h" 58 #include "var.h" 59 #include "options.h" 60 #include "input.h" 61 #include "output.h" 62 #include "syntax.h" 63 #include "memalloc.h" 64 #include "error.h" 65 #include "init.h" 66 #include "mystring.h" 67 #include <sys/types.h> 68 #include <sys/stat.h> 69 #include <fcntl.h> 70 #include <errno.h> 71 72 73 #define CMDTABLESIZE 31 /* should be prime */ 74 #define ARB 1 /* actual size determined at run time */ 75 76 77 78 struct tblentry { 79 struct tblentry *next; /* next entry in hash chain */ 80 union param param; /* definition of builtin function */ 81 short cmdtype; /* index identifying command */ 82 char rehash; /* if set, cd done since entry created */ 83 char cmdname[ARB]; /* name of command */ 84 }; 85 86 87 STATIC struct tblentry *cmdtable[CMDTABLESIZE]; 88 STATIC int builtinloc = -1; /* index in path of %builtin, or -1 */ 89 90 91 #ifdef __STDC__ 92 STATIC void tryexec(char *, char **, char **); 93 STATIC void execinterp(char **, char **); 94 STATIC void printentry(struct tblentry *, int); 95 STATIC void clearcmdentry(int); 96 STATIC struct tblentry *cmdlookup(char *, int); 97 STATIC void delete_cmd_entry(void); 98 #else 99 STATIC void tryexec(); 100 STATIC void execinterp(); 101 STATIC void printentry(); 102 STATIC void clearcmdentry(); 103 STATIC struct tblentry *cmdlookup(); 104 STATIC void delete_cmd_entry(); 105 #endif 106 107 108 109 /* 110 * Exec a program. Never returns. If you change this routine, you may 111 * have to change the find_command routine as well. 112 */ 113 114 void 115 shellexec(argv, envp, path, index) 116 char **argv, **envp; 117 char *path; 118 { 119 char *cmdname; 120 int e; 121 122 if (strchr(argv[0], '/') != NULL) { 123 tryexec(argv[0], argv, envp); 124 e = errno; 125 } else { 126 e = ENOENT; 127 while ((cmdname = padvance(&path, argv[0])) != NULL) { 128 if (--index < 0 && pathopt == NULL) { 129 tryexec(cmdname, argv, envp); 130 if (errno != ENOENT && errno != ENOTDIR) 131 e = errno; 132 } 133 stunalloc(cmdname); 134 } 135 } 136 error2(argv[0], errmsg(e, E_EXEC)); 137 } 138 139 140 STATIC void 141 tryexec(cmd, argv, envp) 142 char *cmd; 143 char **argv; 144 char **envp; 145 { 146 int e; 147 char *p; 148 149 #ifdef SYSV 150 do { 151 execve(cmd, argv, envp); 152 } while (errno == EINTR); 153 #else 154 execve(cmd, argv, envp); 155 #endif 156 e = errno; 157 if (e == ENOEXEC) { 158 initshellproc(); 159 setinputfile(cmd, 0); 160 commandname = arg0 = savestr(argv[0]); 161 #ifndef BSD 162 pgetc(); pungetc(); /* fill up input buffer */ 163 p = parsenextc; 164 if (parsenleft > 2 && p[0] == '#' && p[1] == '!') { 165 argv[0] = cmd; 166 execinterp(argv, envp); 167 } 168 #endif 169 setparam(argv + 1); 170 exraise(EXSHELLPROC); 171 /*NOTREACHED*/ 172 } 173 errno = e; 174 } 175 176 177 #ifndef BSD 178 /* 179 * Execute an interpreter introduced by "#!", for systems where this 180 * feature has not been built into the kernel. If the interpreter is 181 * the shell, return (effectively ignoring the "#!"). If the execution 182 * of the interpreter fails, exit. 183 * 184 * This code peeks inside the input buffer in order to avoid actually 185 * reading any input. It would benefit from a rewrite. 186 */ 187 188 #define NEWARGS 5 189 190 STATIC void 191 execinterp(argv, envp) 192 char **argv, **envp; 193 { 194 int n; 195 char *inp; 196 char *outp; 197 char c; 198 char *p; 199 char **ap; 200 char *newargs[NEWARGS]; 201 int i; 202 char **ap2; 203 char **new; 204 205 n = parsenleft - 2; 206 inp = parsenextc + 2; 207 ap = newargs; 208 for (;;) { 209 while (--n >= 0 && (*inp == ' ' || *inp == '\t')) 210 inp++; 211 if (n < 0) 212 goto bad; 213 if ((c = *inp++) == '\n') 214 break; 215 if (ap == &newargs[NEWARGS]) 216 bad: error("Bad #! line"); 217 STARTSTACKSTR(outp); 218 do { 219 STPUTC(c, outp); 220 } while (--n >= 0 && (c = *inp++) != ' ' && c != '\t' && c != '\n'); 221 STPUTC('\0', outp); 222 n++, inp--; 223 *ap++ = grabstackstr(outp); 224 } 225 if (ap == newargs + 1) { /* if no args, maybe no exec is needed */ 226 p = newargs[0]; 227 for (;;) { 228 if (equal(p, "sh") || equal(p, "ash")) { 229 return; 230 } 231 while (*p != '/') { 232 if (*p == '\0') 233 goto break2; 234 p++; 235 } 236 p++; 237 } 238 break2:; 239 } 240 i = (char *)ap - (char *)newargs; /* size in bytes */ 241 if (i == 0) 242 error("Bad #! line"); 243 for (ap2 = argv ; *ap2++ != NULL ; ); 244 new = ckmalloc(i + ((char *)ap2 - (char *)argv)); 245 ap = newargs, ap2 = new; 246 while ((i -= sizeof (char **)) >= 0) 247 *ap2++ = *ap++; 248 ap = argv; 249 while (*ap2++ = *ap++); 250 shellexec(new, envp, pathval(), 0); 251 } 252 #endif 253 254 255 256 /* 257 * Do a path search. The variable path (passed by reference) should be 258 * set to the start of the path before the first call; padvance will update 259 * this value as it proceeds. Successive calls to padvance will return 260 * the possible path expansions in sequence. If an option (indicated by 261 * a percent sign) appears in the path entry then the global variable 262 * pathopt will be set to point to it; otherwise pathopt will be set to 263 * NULL. 264 */ 265 266 char *pathopt; 267 268 char * 269 padvance(path, name) 270 char **path; 271 char *name; 272 { 273 register char *p, *q; 274 char *start; 275 int len; 276 277 if (*path == NULL) 278 return NULL; 279 start = *path; 280 for (p = start ; *p && *p != ':' && *p != '%' ; p++); 281 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */ 282 while (stackblocksize() < len) 283 growstackblock(); 284 q = stackblock(); 285 if (p != start) { 286 bcopy(start, q, p - start); 287 q += p - start; 288 *q++ = '/'; 289 } 290 strcpy(q, name); 291 pathopt = NULL; 292 if (*p == '%') { 293 pathopt = ++p; 294 while (*p && *p != ':') p++; 295 } 296 if (*p == ':') 297 *path = p + 1; 298 else 299 *path = NULL; 300 return stalloc(len); 301 } 302 303 304 305 /*** Command hashing code ***/ 306 307 308 hashcmd(argc, argv) char **argv; { 309 struct tblentry **pp; 310 struct tblentry *cmdp; 311 int c; 312 int verbose; 313 struct cmdentry entry; 314 char *name; 315 316 verbose = 0; 317 while ((c = nextopt("rv")) != '\0') { 318 if (c == 'r') { 319 clearcmdentry(0); 320 } else if (c == 'v') { 321 verbose++; 322 } 323 } 324 if (*argptr == NULL) { 325 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 326 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 327 printentry(cmdp, verbose); 328 } 329 } 330 return 0; 331 } 332 while ((name = *argptr) != NULL) { 333 if ((cmdp = cmdlookup(name, 0)) != NULL 334 && (cmdp->cmdtype == CMDNORMAL 335 || cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)) 336 delete_cmd_entry(); 337 find_command(name, &entry, 1); 338 if (verbose) { 339 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */ 340 cmdp = cmdlookup(name, 0); 341 printentry(cmdp, verbose); 342 } 343 flushall(); 344 } 345 argptr++; 346 } 347 return 0; 348 } 349 350 351 STATIC void 352 printentry(cmdp, verbose) 353 struct tblentry *cmdp; 354 int verbose; 355 { 356 int index; 357 char *path; 358 char *name; 359 360 if (cmdp->cmdtype == CMDNORMAL) { 361 index = cmdp->param.index; 362 path = pathval(); 363 do { 364 name = padvance(&path, cmdp->cmdname); 365 stunalloc(name); 366 } while (--index >= 0); 367 out1str(name); 368 } else if (cmdp->cmdtype == CMDBUILTIN) { 369 out1fmt("builtin %s", cmdp->cmdname); 370 } else if (cmdp->cmdtype == CMDFUNCTION) { 371 out1fmt("function %s", cmdp->cmdname); 372 if (verbose) { 373 INTOFF; 374 name = commandtext(cmdp->param.func); 375 out1c(' '); 376 out1str(name); 377 ckfree(name); 378 INTON; 379 } 380 #ifdef DEBUG 381 } else { 382 error("internal error: cmdtype %d", cmdp->cmdtype); 383 #endif 384 } 385 if (cmdp->rehash) 386 out1c('*'); 387 out1c('\n'); 388 } 389 390 391 392 /* 393 * Resolve a command name. If you change this routine, you may have to 394 * change the shellexec routine as well. 395 */ 396 397 void 398 find_command(name, entry, printerr) 399 char *name; 400 struct cmdentry *entry; 401 { 402 struct tblentry *cmdp; 403 int index; 404 int prev; 405 char *path; 406 char *fullname; 407 struct stat statb; 408 int e; 409 int i; 410 411 /* If name contains a slash, don't use the hash table */ 412 if (strchr(name, '/') != NULL) { 413 entry->cmdtype = CMDNORMAL; 414 entry->u.index = 0; 415 return; 416 } 417 418 /* If name is in the table, and not invalidated by cd, we're done */ 419 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) 420 goto success; 421 422 /* If %builtin not in path, check for builtin next */ 423 if (builtinloc < 0 && (i = find_builtin(name)) >= 0) { 424 INTOFF; 425 cmdp = cmdlookup(name, 1); 426 cmdp->cmdtype = CMDBUILTIN; 427 cmdp->param.index = i; 428 INTON; 429 goto success; 430 } 431 432 /* We have to search path. */ 433 prev = -1; /* where to start */ 434 if (cmdp) { /* doing a rehash */ 435 if (cmdp->cmdtype == CMDBUILTIN) 436 prev = builtinloc; 437 else 438 prev = cmdp->param.index; 439 } 440 441 path = pathval(); 442 e = ENOENT; 443 index = -1; 444 loop: 445 while ((fullname = padvance(&path, name)) != NULL) { 446 stunalloc(fullname); 447 index++; 448 if (pathopt) { 449 if (prefix("builtin", pathopt)) { 450 if ((i = find_builtin(name)) < 0) 451 goto loop; 452 INTOFF; 453 cmdp = cmdlookup(name, 1); 454 cmdp->cmdtype = CMDBUILTIN; 455 cmdp->param.index = i; 456 INTON; 457 goto success; 458 } else if (prefix("func", pathopt)) { 459 /* handled below */ 460 } else { 461 goto loop; /* ignore unimplemented options */ 462 } 463 } 464 /* if rehash, don't redo absolute path names */ 465 if (fullname[0] == '/' && index <= prev) { 466 if (index < prev) 467 goto loop; 468 TRACE(("searchexec \"%s\": no change\n", name)); 469 goto success; 470 } 471 while (stat(fullname, &statb) < 0) { 472 #ifdef SYSV 473 if (errno == EINTR) 474 continue; 475 #endif 476 if (errno != ENOENT && errno != ENOTDIR) 477 e = errno; 478 goto loop; 479 } 480 e = EACCES; /* if we fail, this will be the error */ 481 if ((statb.st_mode & S_IFMT) != S_IFREG) 482 goto loop; 483 if (pathopt) { /* this is a %func directory */ 484 stalloc(strlen(fullname) + 1); 485 readcmdfile(fullname); 486 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 487 error("%s not defined in %s", name, fullname); 488 stunalloc(fullname); 489 goto success; 490 } 491 #ifdef notdef 492 if (statb.st_uid == geteuid()) { 493 if ((statb.st_mode & 0100) == 0) 494 goto loop; 495 } else if (statb.st_gid == getegid()) { 496 if ((statb.st_mode & 010) == 0) 497 goto loop; 498 } else { 499 if ((statb.st_mode & 01) == 0) 500 goto loop; 501 } 502 #endif 503 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 504 INTOFF; 505 cmdp = cmdlookup(name, 1); 506 cmdp->cmdtype = CMDNORMAL; 507 cmdp->param.index = index; 508 INTON; 509 goto success; 510 } 511 512 /* We failed. If there was an entry for this command, delete it */ 513 if (cmdp) 514 delete_cmd_entry(); 515 if (printerr) 516 outfmt(out2, "%s: %s\n", name, errmsg(e, E_EXEC)); 517 entry->cmdtype = CMDUNKNOWN; 518 return; 519 520 success: 521 cmdp->rehash = 0; 522 entry->cmdtype = cmdp->cmdtype; 523 entry->u = cmdp->param; 524 } 525 526 527 528 /* 529 * Search the table of builtin commands. 530 */ 531 532 int 533 find_builtin(name) 534 char *name; 535 { 536 const register struct builtincmd *bp; 537 538 for (bp = builtincmd ; bp->name ; bp++) { 539 if (*bp->name == *name && equal(bp->name, name)) 540 return bp->code; 541 } 542 return -1; 543 } 544 545 546 547 /* 548 * Called when a cd is done. Marks all commands so the next time they 549 * are executed they will be rehashed. 550 */ 551 552 void 553 hashcd() { 554 struct tblentry **pp; 555 struct tblentry *cmdp; 556 557 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 558 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 559 if (cmdp->cmdtype == CMDNORMAL 560 || cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0) 561 cmdp->rehash = 1; 562 } 563 } 564 } 565 566 567 568 /* 569 * Called before PATH is changed. The argument is the new value of PATH; 570 * pathval() still returns the old value at this point. Called with 571 * interrupts off. 572 */ 573 574 void 575 changepath(newval) 576 char *newval; 577 { 578 char *old, *new; 579 int index; 580 int firstchange; 581 int bltin; 582 int hasdot; 583 584 old = pathval(); 585 new = newval; 586 firstchange = 9999; /* assume no change */ 587 index = hasdot = 0; 588 bltin = -1; 589 if (*new == ':') 590 hasdot++; 591 for (;;) { 592 if (*old != *new) { 593 firstchange = index; 594 if (*old == '\0' && *new == ':' 595 || *old == ':' && *new == '\0') 596 firstchange++; 597 old = new; /* ignore subsequent differences */ 598 } 599 if (*new == '\0') 600 break; 601 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1)) 602 bltin = index; 603 if (*new == ':') { 604 char c = *(new+1); 605 606 index++; 607 if (c == ':' || c == '\0' || (c == '.' && 608 ((c = *(new+2)) == ':' || c == '\0'))) 609 hasdot++; 610 } 611 new++, old++; 612 } 613 if (hasdot && geteuid() == 0) 614 out2str("sh: warning: running as root with dot in PATH\n"); 615 if (builtinloc < 0 && bltin >= 0) 616 builtinloc = bltin; /* zap builtins */ 617 if (builtinloc >= 0 && bltin < 0) 618 firstchange = 0; 619 clearcmdentry(firstchange); 620 builtinloc = bltin; 621 } 622 623 624 /* 625 * Clear out command entries. The argument specifies the first entry in 626 * PATH which has changed. 627 */ 628 629 STATIC void 630 clearcmdentry(firstchange) { 631 struct tblentry **tblp; 632 struct tblentry **pp; 633 struct tblentry *cmdp; 634 635 INTOFF; 636 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 637 pp = tblp; 638 while ((cmdp = *pp) != NULL) { 639 if (cmdp->cmdtype == CMDNORMAL && cmdp->param.index >= firstchange 640 || cmdp->cmdtype == CMDBUILTIN && builtinloc >= firstchange) { 641 *pp = cmdp->next; 642 ckfree(cmdp); 643 } else { 644 pp = &cmdp->next; 645 } 646 } 647 } 648 INTON; 649 } 650 651 652 /* 653 * Delete all functions. 654 */ 655 656 #ifdef mkinit 657 MKINIT void deletefuncs(); 658 659 SHELLPROC { 660 deletefuncs(); 661 } 662 #endif 663 664 void 665 deletefuncs() { 666 struct tblentry **tblp; 667 struct tblentry **pp; 668 struct tblentry *cmdp; 669 670 INTOFF; 671 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 672 pp = tblp; 673 while ((cmdp = *pp) != NULL) { 674 if (cmdp->cmdtype == CMDFUNCTION) { 675 *pp = cmdp->next; 676 freefunc(cmdp->param.func); 677 ckfree(cmdp); 678 } else { 679 pp = &cmdp->next; 680 } 681 } 682 } 683 INTON; 684 } 685 686 687 688 /* 689 * Locate a command in the command hash table. If "add" is nonzero, 690 * add the command to the table if it is not already present. The 691 * variable "lastcmdentry" is set to point to the address of the link 692 * pointing to the entry, so that delete_cmd_entry can delete the 693 * entry. 694 */ 695 696 struct tblentry **lastcmdentry; 697 698 699 STATIC struct tblentry * 700 cmdlookup(name, add) 701 char *name; 702 { 703 int hashval; 704 register char *p; 705 struct tblentry *cmdp; 706 struct tblentry **pp; 707 708 p = name; 709 hashval = *p << 4; 710 while (*p) 711 hashval += *p++; 712 hashval &= 0x7FFF; 713 pp = &cmdtable[hashval % CMDTABLESIZE]; 714 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 715 if (equal(cmdp->cmdname, name)) 716 break; 717 pp = &cmdp->next; 718 } 719 if (add && cmdp == NULL) { 720 INTOFF; 721 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB 722 + strlen(name) + 1); 723 cmdp->next = NULL; 724 cmdp->cmdtype = CMDUNKNOWN; 725 cmdp->rehash = 0; 726 strcpy(cmdp->cmdname, name); 727 INTON; 728 } 729 lastcmdentry = pp; 730 return cmdp; 731 } 732 733 /* 734 * Delete the command entry returned on the last lookup. 735 */ 736 737 STATIC void 738 delete_cmd_entry() { 739 struct tblentry *cmdp; 740 741 INTOFF; 742 cmdp = *lastcmdentry; 743 *lastcmdentry = cmdp->next; 744 ckfree(cmdp); 745 INTON; 746 } 747 748 749 750 #ifdef notdef 751 void 752 getcmdentry(name, entry) 753 char *name; 754 struct cmdentry *entry; 755 { 756 struct tblentry *cmdp = cmdlookup(name, 0); 757 758 if (cmdp) { 759 entry->u = cmdp->param; 760 entry->cmdtype = cmdp->cmdtype; 761 } else { 762 entry->cmdtype = CMDUNKNOWN; 763 entry->u.index = 0; 764 } 765 } 766 #endif 767 768 769 /* 770 * Add a new command entry, replacing any existing command entry for 771 * the same name. 772 */ 773 774 void 775 addcmdentry(name, entry) 776 char *name; 777 struct cmdentry *entry; 778 { 779 struct tblentry *cmdp; 780 781 INTOFF; 782 cmdp = cmdlookup(name, 1); 783 if (cmdp->cmdtype == CMDFUNCTION) { 784 freefunc(cmdp->param.func); 785 } 786 cmdp->cmdtype = entry->cmdtype; 787 cmdp->param = entry->u; 788 INTON; 789 } 790 791 792 /* 793 * Define a shell function. 794 */ 795 796 void 797 defun(name, func) 798 char *name; 799 union node *func; 800 { 801 struct cmdentry entry; 802 803 INTOFF; 804 entry.cmdtype = CMDFUNCTION; 805 entry.u.func = copyfunc(func); 806 addcmdentry(name, &entry); 807 INTON; 808 } 809 810 811 /* 812 * Delete a function if it exists. 813 */ 814 815 int 816 unsetfunc(name) 817 char *name; 818 { 819 struct tblentry *cmdp; 820 821 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 822 freefunc(cmdp->param.func); 823 delete_cmd_entry(); 824 return (0); 825 } 826 return (1); 827 } 828