1 /*- 2 * Copyright (c) 1991, 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 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)exec.c 8.4 (Berkeley) 6/8/95"; 40 #endif 41 #endif /* not lint */ 42 #include <sys/cdefs.h> 43 __FBSDID("$FreeBSD$"); 44 45 #include <sys/types.h> 46 #include <sys/stat.h> 47 #include <unistd.h> 48 #include <fcntl.h> 49 #include <errno.h> 50 #include <stdlib.h> 51 52 /* 53 * When commands are first encountered, they are entered in a hash table. 54 * This ensures that a full path search will not have to be done for them 55 * on each invocation. 56 * 57 * We should investigate converting to a linear search, even though that 58 * would make the command name "hash" a misnomer. 59 */ 60 61 #include "shell.h" 62 #include "main.h" 63 #include "nodes.h" 64 #include "parser.h" 65 #include "redir.h" 66 #include "eval.h" 67 #include "exec.h" 68 #include "builtins.h" 69 #include "var.h" 70 #include "options.h" 71 #include "input.h" 72 #include "output.h" 73 #include "syntax.h" 74 #include "memalloc.h" 75 #include "error.h" 76 #include "init.h" 77 #include "mystring.h" 78 #include "show.h" 79 #include "jobs.h" 80 #include "alias.h" 81 82 83 #define CMDTABLESIZE 31 /* should be prime */ 84 #define ARB 1 /* actual size determined at run time */ 85 86 87 88 struct tblentry { 89 struct tblentry *next; /* next entry in hash chain */ 90 union param param; /* definition of builtin function */ 91 short cmdtype; /* index identifying command */ 92 char rehash; /* if set, cd done since entry created */ 93 char cmdname[ARB]; /* name of command */ 94 }; 95 96 97 STATIC struct tblentry *cmdtable[CMDTABLESIZE]; 98 STATIC int builtinloc = -1; /* index in path of %builtin, or -1 */ 99 int exerrno = 0; /* Last exec error */ 100 101 102 STATIC void tryexec(char *, char **, char **); 103 STATIC void printentry(struct tblentry *, int); 104 STATIC struct tblentry *cmdlookup(char *, int); 105 STATIC void delete_cmd_entry(void); 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(char **argv, char **envp, char *path, int index) 116 { 117 char *cmdname; 118 int e; 119 120 if (strchr(argv[0], '/') != NULL) { 121 tryexec(argv[0], argv, envp); 122 e = errno; 123 } else { 124 e = ENOENT; 125 while ((cmdname = padvance(&path, argv[0])) != NULL) { 126 if (--index < 0 && pathopt == NULL) { 127 tryexec(cmdname, argv, envp); 128 if (errno != ENOENT && errno != ENOTDIR) 129 e = errno; 130 } 131 stunalloc(cmdname); 132 } 133 } 134 135 /* Map to POSIX errors */ 136 switch (e) { 137 case EACCES: 138 exerrno = 126; 139 break; 140 case ENOENT: 141 exerrno = 127; 142 break; 143 default: 144 exerrno = 2; 145 break; 146 } 147 if (e == ENOENT || e == ENOTDIR) 148 exerror(EXEXEC, "%s: not found", argv[0]); 149 exerror(EXEXEC, "%s: %s", argv[0], strerror(e)); 150 } 151 152 153 STATIC void 154 tryexec(char *cmd, char **argv, char **envp) 155 { 156 int e; 157 158 execve(cmd, argv, envp); 159 e = errno; 160 if (e == ENOEXEC) { 161 initshellproc(); 162 setinputfile(cmd, 0); 163 commandname = arg0 = savestr(argv[0]); 164 setparam(argv + 1); 165 exraise(EXSHELLPROC); 166 /*NOTREACHED*/ 167 } 168 errno = e; 169 } 170 171 /* 172 * Do a path search. The variable path (passed by reference) should be 173 * set to the start of the path before the first call; padvance will update 174 * this value as it proceeds. Successive calls to padvance will return 175 * the possible path expansions in sequence. If an option (indicated by 176 * a percent sign) appears in the path entry then the global variable 177 * pathopt will be set to point to it; otherwise pathopt will be set to 178 * NULL. 179 */ 180 181 char *pathopt; 182 183 char * 184 padvance(char **path, char *name) 185 { 186 char *p, *q; 187 char *start; 188 int len; 189 190 if (*path == NULL) 191 return NULL; 192 start = *path; 193 for (p = start ; *p && *p != ':' && *p != '%' ; p++); 194 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */ 195 while (stackblocksize() < len) 196 growstackblock(); 197 q = stackblock(); 198 if (p != start) { 199 memcpy(q, start, p - start); 200 q += p - start; 201 *q++ = '/'; 202 } 203 strcpy(q, name); 204 pathopt = NULL; 205 if (*p == '%') { 206 pathopt = ++p; 207 while (*p && *p != ':') p++; 208 } 209 if (*p == ':') 210 *path = p + 1; 211 else 212 *path = NULL; 213 return stalloc(len); 214 } 215 216 217 218 /*** Command hashing code ***/ 219 220 221 int 222 hashcmd(int argc __unused, char **argv __unused) 223 { 224 struct tblentry **pp; 225 struct tblentry *cmdp; 226 int c; 227 int verbose; 228 struct cmdentry entry; 229 char *name; 230 231 verbose = 0; 232 while ((c = nextopt("rv")) != '\0') { 233 if (c == 'r') { 234 clearcmdentry(0); 235 } else if (c == 'v') { 236 verbose++; 237 } 238 } 239 if (*argptr == NULL) { 240 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 241 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 242 if (cmdp->cmdtype == CMDNORMAL) 243 printentry(cmdp, verbose); 244 } 245 } 246 return 0; 247 } 248 while ((name = *argptr) != NULL) { 249 if ((cmdp = cmdlookup(name, 0)) != NULL 250 && (cmdp->cmdtype == CMDNORMAL 251 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))) 252 delete_cmd_entry(); 253 find_command(name, &entry, 1, pathval()); 254 if (verbose) { 255 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */ 256 cmdp = cmdlookup(name, 0); 257 if (cmdp != NULL) 258 printentry(cmdp, verbose); 259 else 260 outfmt(&errout, "%s: not found\n", name); 261 } 262 flushall(); 263 } 264 argptr++; 265 } 266 return 0; 267 } 268 269 270 STATIC void 271 printentry(struct tblentry *cmdp, int verbose) 272 { 273 int index; 274 char *path; 275 char *name; 276 277 if (cmdp->cmdtype == CMDNORMAL) { 278 index = cmdp->param.index; 279 path = pathval(); 280 do { 281 name = padvance(&path, cmdp->cmdname); 282 stunalloc(name); 283 } while (--index >= 0); 284 out1str(name); 285 } else if (cmdp->cmdtype == CMDBUILTIN) { 286 out1fmt("builtin %s", cmdp->cmdname); 287 } else if (cmdp->cmdtype == CMDFUNCTION) { 288 out1fmt("function %s", cmdp->cmdname); 289 if (verbose) { 290 INTOFF; 291 name = commandtext(cmdp->param.func); 292 out1c(' '); 293 out1str(name); 294 ckfree(name); 295 INTON; 296 } 297 #ifdef DEBUG 298 } else { 299 error("internal error: cmdtype %d", cmdp->cmdtype); 300 #endif 301 } 302 if (cmdp->rehash) 303 out1c('*'); 304 out1c('\n'); 305 } 306 307 308 309 /* 310 * Resolve a command name. If you change this routine, you may have to 311 * change the shellexec routine as well. 312 */ 313 314 void 315 find_command(char *name, struct cmdentry *entry, int printerr, char *path) 316 { 317 struct tblentry *cmdp; 318 int index; 319 int prev; 320 char *fullname; 321 struct stat statb; 322 int e; 323 int i; 324 325 /* If name contains a slash, don't use the hash table */ 326 if (strchr(name, '/') != NULL) { 327 entry->cmdtype = CMDNORMAL; 328 entry->u.index = 0; 329 return; 330 } 331 332 /* If name is in the table, and not invalidated by cd, we're done */ 333 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) 334 goto success; 335 336 /* If %builtin not in path, check for builtin next */ 337 if (builtinloc < 0 && (i = find_builtin(name)) >= 0) { 338 INTOFF; 339 cmdp = cmdlookup(name, 1); 340 cmdp->cmdtype = CMDBUILTIN; 341 cmdp->param.index = i; 342 INTON; 343 goto success; 344 } 345 346 /* We have to search path. */ 347 prev = -1; /* where to start */ 348 if (cmdp) { /* doing a rehash */ 349 if (cmdp->cmdtype == CMDBUILTIN) 350 prev = builtinloc; 351 else 352 prev = cmdp->param.index; 353 } 354 355 e = ENOENT; 356 index = -1; 357 loop: 358 while ((fullname = padvance(&path, name)) != NULL) { 359 stunalloc(fullname); 360 index++; 361 if (pathopt) { 362 if (prefix("builtin", pathopt)) { 363 if ((i = find_builtin(name)) < 0) 364 goto loop; 365 INTOFF; 366 cmdp = cmdlookup(name, 1); 367 cmdp->cmdtype = CMDBUILTIN; 368 cmdp->param.index = i; 369 INTON; 370 goto success; 371 } else if (prefix("func", pathopt)) { 372 /* handled below */ 373 } else { 374 goto loop; /* ignore unimplemented options */ 375 } 376 } 377 /* if rehash, don't redo absolute path names */ 378 if (fullname[0] == '/' && index <= prev) { 379 if (index < prev) 380 goto loop; 381 TRACE(("searchexec \"%s\": no change\n", name)); 382 goto success; 383 } 384 if (stat(fullname, &statb) < 0) { 385 if (errno != ENOENT && errno != ENOTDIR) 386 e = errno; 387 goto loop; 388 } 389 e = EACCES; /* if we fail, this will be the error */ 390 if (!S_ISREG(statb.st_mode)) 391 goto loop; 392 if (pathopt) { /* this is a %func directory */ 393 stalloc(strlen(fullname) + 1); 394 readcmdfile(fullname); 395 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 396 error("%s not defined in %s", name, fullname); 397 stunalloc(fullname); 398 goto success; 399 } 400 #ifdef notdef 401 if (statb.st_uid == geteuid()) { 402 if ((statb.st_mode & 0100) == 0) 403 goto loop; 404 } else if (statb.st_gid == getegid()) { 405 if ((statb.st_mode & 010) == 0) 406 goto loop; 407 } else { 408 if ((statb.st_mode & 01) == 0) 409 goto loop; 410 } 411 #endif 412 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 413 INTOFF; 414 cmdp = cmdlookup(name, 1); 415 cmdp->cmdtype = CMDNORMAL; 416 cmdp->param.index = index; 417 INTON; 418 goto success; 419 } 420 421 /* We failed. If there was an entry for this command, delete it */ 422 if (cmdp) 423 delete_cmd_entry(); 424 if (printerr) { 425 if (e == ENOENT || e == ENOTDIR) 426 outfmt(out2, "%s: not found\n", name); 427 else 428 outfmt(out2, "%s: %s\n", name, strerror(e)); 429 } 430 entry->cmdtype = CMDUNKNOWN; 431 return; 432 433 success: 434 cmdp->rehash = 0; 435 entry->cmdtype = cmdp->cmdtype; 436 entry->u = cmdp->param; 437 } 438 439 440 441 /* 442 * Search the table of builtin commands. 443 */ 444 445 int 446 find_builtin(char *name) 447 { 448 const struct builtincmd *bp; 449 450 for (bp = builtincmd ; bp->name ; bp++) { 451 if (*bp->name == *name && equal(bp->name, name)) 452 return bp->code; 453 } 454 return -1; 455 } 456 457 458 459 /* 460 * Called when a cd is done. Marks all commands so the next time they 461 * are executed they will be rehashed. 462 */ 463 464 void 465 hashcd(void) 466 { 467 struct tblentry **pp; 468 struct tblentry *cmdp; 469 470 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 471 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 472 if (cmdp->cmdtype == CMDNORMAL 473 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)) 474 cmdp->rehash = 1; 475 } 476 } 477 } 478 479 480 481 /* 482 * Called before PATH is changed. The argument is the new value of PATH; 483 * pathval() still returns the old value at this point. Called with 484 * interrupts off. 485 */ 486 487 void 488 changepath(const char *newval) 489 { 490 const char *old, *new; 491 int index; 492 int firstchange; 493 int bltin; 494 495 old = pathval(); 496 new = newval; 497 firstchange = 9999; /* assume no change */ 498 index = 0; 499 bltin = -1; 500 for (;;) { 501 if (*old != *new) { 502 firstchange = index; 503 if ((*old == '\0' && *new == ':') 504 || (*old == ':' && *new == '\0')) 505 firstchange++; 506 old = new; /* ignore subsequent differences */ 507 } 508 if (*new == '\0') 509 break; 510 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1)) 511 bltin = index; 512 if (*new == ':') { 513 index++; 514 } 515 new++, old++; 516 } 517 if (builtinloc < 0 && bltin >= 0) 518 builtinloc = bltin; /* zap builtins */ 519 if (builtinloc >= 0 && bltin < 0) 520 firstchange = 0; 521 clearcmdentry(firstchange); 522 builtinloc = bltin; 523 } 524 525 526 /* 527 * Clear out command entries. The argument specifies the first entry in 528 * PATH which has changed. 529 */ 530 531 void 532 clearcmdentry(int firstchange) 533 { 534 struct tblentry **tblp; 535 struct tblentry **pp; 536 struct tblentry *cmdp; 537 538 INTOFF; 539 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 540 pp = tblp; 541 while ((cmdp = *pp) != NULL) { 542 if ((cmdp->cmdtype == CMDNORMAL && 543 cmdp->param.index >= firstchange) 544 || (cmdp->cmdtype == CMDBUILTIN && 545 builtinloc >= firstchange)) { 546 *pp = cmdp->next; 547 ckfree(cmdp); 548 } else { 549 pp = &cmdp->next; 550 } 551 } 552 } 553 INTON; 554 } 555 556 557 /* 558 * Delete all functions. 559 */ 560 561 #ifdef mkinit 562 MKINIT void deletefuncs(); 563 564 SHELLPROC { 565 deletefuncs(); 566 } 567 #endif 568 569 void 570 deletefuncs(void) 571 { 572 struct tblentry **tblp; 573 struct tblentry **pp; 574 struct tblentry *cmdp; 575 576 INTOFF; 577 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 578 pp = tblp; 579 while ((cmdp = *pp) != NULL) { 580 if (cmdp->cmdtype == CMDFUNCTION) { 581 *pp = cmdp->next; 582 freefunc(cmdp->param.func); 583 ckfree(cmdp); 584 } else { 585 pp = &cmdp->next; 586 } 587 } 588 } 589 INTON; 590 } 591 592 593 594 /* 595 * Locate a command in the command hash table. If "add" is nonzero, 596 * add the command to the table if it is not already present. The 597 * variable "lastcmdentry" is set to point to the address of the link 598 * pointing to the entry, so that delete_cmd_entry can delete the 599 * entry. 600 */ 601 602 struct tblentry **lastcmdentry; 603 604 605 STATIC struct tblentry * 606 cmdlookup(char *name, int add) 607 { 608 int hashval; 609 char *p; 610 struct tblentry *cmdp; 611 struct tblentry **pp; 612 613 p = name; 614 hashval = *p << 4; 615 while (*p) 616 hashval += *p++; 617 hashval &= 0x7FFF; 618 pp = &cmdtable[hashval % CMDTABLESIZE]; 619 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 620 if (equal(cmdp->cmdname, name)) 621 break; 622 pp = &cmdp->next; 623 } 624 if (add && cmdp == NULL) { 625 INTOFF; 626 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB 627 + strlen(name) + 1); 628 cmdp->next = NULL; 629 cmdp->cmdtype = CMDUNKNOWN; 630 cmdp->rehash = 0; 631 strcpy(cmdp->cmdname, name); 632 INTON; 633 } 634 lastcmdentry = pp; 635 return cmdp; 636 } 637 638 /* 639 * Delete the command entry returned on the last lookup. 640 */ 641 642 STATIC void 643 delete_cmd_entry(void) 644 { 645 struct tblentry *cmdp; 646 647 INTOFF; 648 cmdp = *lastcmdentry; 649 *lastcmdentry = cmdp->next; 650 ckfree(cmdp); 651 INTON; 652 } 653 654 655 656 /* 657 * Add a new command entry, replacing any existing command entry for 658 * the same name. 659 */ 660 661 void 662 addcmdentry(char *name, struct cmdentry *entry) 663 { 664 struct tblentry *cmdp; 665 666 INTOFF; 667 cmdp = cmdlookup(name, 1); 668 if (cmdp->cmdtype == CMDFUNCTION) { 669 freefunc(cmdp->param.func); 670 } 671 cmdp->cmdtype = entry->cmdtype; 672 cmdp->param = entry->u; 673 INTON; 674 } 675 676 677 /* 678 * Define a shell function. 679 */ 680 681 void 682 defun(char *name, union node *func) 683 { 684 struct cmdentry entry; 685 686 INTOFF; 687 entry.cmdtype = CMDFUNCTION; 688 entry.u.func = copyfunc(func); 689 addcmdentry(name, &entry); 690 INTON; 691 } 692 693 694 /* 695 * Delete a function if it exists. 696 */ 697 698 int 699 unsetfunc(char *name) 700 { 701 struct tblentry *cmdp; 702 703 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 704 freefunc(cmdp->param.func); 705 delete_cmd_entry(); 706 return (0); 707 } 708 return (1); 709 } 710 711 /* 712 * Locate and print what a word is... 713 */ 714 715 int 716 typecmd(int argc, char **argv) 717 { 718 struct cmdentry entry; 719 struct tblentry *cmdp; 720 char **pp; 721 struct alias *ap; 722 int i; 723 int error = 0; 724 extern char *const parsekwd[]; 725 726 for (i = 1; i < argc; i++) { 727 out1str(argv[i]); 728 /* First look at the keywords */ 729 for (pp = (char **)parsekwd; *pp; pp++) 730 if (**pp == *argv[i] && equal(*pp, argv[i])) 731 break; 732 733 if (*pp) { 734 out1str(" is a shell keyword\n"); 735 continue; 736 } 737 738 /* Then look at the aliases */ 739 if ((ap = lookupalias(argv[i], 1)) != NULL) { 740 out1fmt(" is an alias for %s\n", ap->val); 741 continue; 742 } 743 744 /* Then check if it is a tracked alias */ 745 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) { 746 entry.cmdtype = cmdp->cmdtype; 747 entry.u = cmdp->param; 748 } 749 else { 750 /* Finally use brute force */ 751 find_command(argv[i], &entry, 0, pathval()); 752 } 753 754 switch (entry.cmdtype) { 755 case CMDNORMAL: { 756 if (strchr(argv[i], '/') == NULL) { 757 char *path = pathval(), *name; 758 int j = entry.u.index; 759 do { 760 name = padvance(&path, argv[i]); 761 stunalloc(name); 762 } while (--j >= 0); 763 out1fmt(" is%s %s\n", 764 cmdp ? " a tracked alias for" : "", name); 765 } else { 766 if (access(argv[i], X_OK) == 0) 767 out1fmt(" is %s\n", argv[i]); 768 else 769 out1fmt(": %s\n", strerror(errno)); 770 } 771 break; 772 } 773 case CMDFUNCTION: 774 out1str(" is a shell function\n"); 775 break; 776 777 case CMDBUILTIN: 778 out1str(" is a shell builtin\n"); 779 break; 780 781 default: 782 out1str(": not found\n"); 783 error |= 127; 784 break; 785 } 786 } 787 return error; 788 } 789