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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #ifndef lint 34 #if 0 35 static char sccsid[] = "@(#)exec.c 8.4 (Berkeley) 6/8/95"; 36 #endif 37 #endif /* not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 #include <unistd.h> 44 #include <fcntl.h> 45 #include <errno.h> 46 #include <paths.h> 47 #include <stdlib.h> 48 49 /* 50 * When commands are first encountered, they are entered in a hash table. 51 * This ensures that a full path search will not have to be done for them 52 * on each invocation. 53 * 54 * We should investigate converting to a linear search, even though that 55 * would make the command name "hash" a misnomer. 56 */ 57 58 #include "shell.h" 59 #include "main.h" 60 #include "nodes.h" 61 #include "parser.h" 62 #include "redir.h" 63 #include "eval.h" 64 #include "exec.h" 65 #include "builtins.h" 66 #include "var.h" 67 #include "options.h" 68 #include "input.h" 69 #include "output.h" 70 #include "syntax.h" 71 #include "memalloc.h" 72 #include "error.h" 73 #include "init.h" 74 #include "mystring.h" 75 #include "show.h" 76 #include "jobs.h" 77 #include "alias.h" 78 79 80 #define CMDTABLESIZE 31 /* should be prime */ 81 82 83 84 struct tblentry { 85 struct tblentry *next; /* next entry in hash chain */ 86 union param param; /* definition of builtin function */ 87 int special; /* flag for special builtin commands */ 88 signed char cmdtype; /* index identifying command */ 89 char rehash; /* if set, cd done since entry created */ 90 char cmdname[]; /* name of command */ 91 }; 92 93 94 static struct tblentry *cmdtable[CMDTABLESIZE]; 95 int exerrno = 0; /* Last exec error */ 96 97 98 static void tryexec(char *, char **, char **); 99 static void printentry(struct tblentry *, int); 100 static struct tblentry *cmdlookup(const char *, int); 101 static void delete_cmd_entry(void); 102 static void addcmdentry(const char *, struct cmdentry *); 103 104 105 106 /* 107 * Exec a program. Never returns. If you change this routine, you may 108 * have to change the find_command routine as well. 109 * 110 * The argv array may be changed and element argv[-1] should be writable. 111 */ 112 113 void 114 shellexec(char **argv, char **envp, const char *path, int idx) 115 { 116 char *cmdname; 117 int e; 118 119 if (strchr(argv[0], '/') != NULL) { 120 tryexec(argv[0], argv, envp); 121 e = errno; 122 } else { 123 e = ENOENT; 124 while ((cmdname = padvance(&path, argv[0])) != NULL) { 125 if (--idx < 0 && pathopt == NULL) { 126 tryexec(cmdname, argv, envp); 127 if (errno != ENOENT && errno != ENOTDIR) 128 e = errno; 129 if (e == ENOEXEC) 130 break; 131 } 132 stunalloc(cmdname); 133 } 134 } 135 136 /* Map to POSIX errors */ 137 if (e == ENOENT || e == ENOTDIR) { 138 exerrno = 127; 139 exerror(EXEXEC, "%s: not found", argv[0]); 140 } else { 141 exerrno = 126; 142 exerror(EXEXEC, "%s: %s", argv[0], strerror(e)); 143 } 144 } 145 146 147 static void 148 tryexec(char *cmd, char **argv, char **envp) 149 { 150 int e, in; 151 ssize_t n; 152 char buf[256]; 153 154 execve(cmd, argv, envp); 155 e = errno; 156 if (e == ENOEXEC) { 157 INTOFF; 158 in = open(cmd, O_RDONLY | O_NONBLOCK); 159 if (in != -1) { 160 n = pread(in, buf, sizeof buf, 0); 161 close(in); 162 if (n > 0 && memchr(buf, '\0', n) != NULL) { 163 errno = ENOEXEC; 164 return; 165 } 166 } 167 *argv = cmd; 168 *--argv = _PATH_BSHELL; 169 execve(_PATH_BSHELL, argv, envp); 170 } 171 errno = e; 172 } 173 174 /* 175 * Do a path search. The variable path (passed by reference) should be 176 * set to the start of the path before the first call; padvance will update 177 * this value as it proceeds. Successive calls to padvance will return 178 * the possible path expansions in sequence. If an option (indicated by 179 * a percent sign) appears in the path entry then the global variable 180 * pathopt will be set to point to it; otherwise pathopt will be set to 181 * NULL. 182 */ 183 184 const char *pathopt; 185 186 char * 187 padvance(const char **path, const char *name) 188 { 189 const char *p, *start; 190 char *q; 191 int len; 192 193 if (*path == NULL) 194 return NULL; 195 start = *path; 196 for (p = start; *p && *p != ':' && *p != '%'; p++) 197 ; /* nothing */ 198 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */ 199 STARTSTACKSTR(q); 200 CHECKSTRSPACE(len, q); 201 if (p != start) { 202 memcpy(q, start, p - start); 203 q += p - start; 204 *q++ = '/'; 205 } 206 strcpy(q, name); 207 pathopt = NULL; 208 if (*p == '%') { 209 pathopt = ++p; 210 while (*p && *p != ':') p++; 211 } 212 if (*p == ':') 213 *path = p + 1; 214 else 215 *path = NULL; 216 return stalloc(len); 217 } 218 219 220 221 /*** Command hashing code ***/ 222 223 224 int 225 hashcmd(int argc __unused, char **argv __unused) 226 { 227 struct tblentry **pp; 228 struct tblentry *cmdp; 229 int c; 230 int verbose; 231 struct cmdentry entry; 232 char *name; 233 int errors; 234 235 errors = 0; 236 verbose = 0; 237 while ((c = nextopt("rv")) != '\0') { 238 if (c == 'r') { 239 clearcmdentry(); 240 } else if (c == 'v') { 241 verbose++; 242 } 243 } 244 if (*argptr == NULL) { 245 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 246 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 247 if (cmdp->cmdtype == CMDNORMAL) 248 printentry(cmdp, verbose); 249 } 250 } 251 return 0; 252 } 253 while ((name = *argptr) != NULL) { 254 if ((cmdp = cmdlookup(name, 0)) != NULL 255 && cmdp->cmdtype == CMDNORMAL) 256 delete_cmd_entry(); 257 find_command(name, &entry, DO_ERR, pathval()); 258 if (entry.cmdtype == CMDUNKNOWN) 259 errors = 1; 260 else if (verbose) { 261 cmdp = cmdlookup(name, 0); 262 if (cmdp != NULL) 263 printentry(cmdp, verbose); 264 else { 265 outfmt(out2, "%s: not found\n", name); 266 errors = 1; 267 } 268 flushall(); 269 } 270 argptr++; 271 } 272 return errors; 273 } 274 275 276 static void 277 printentry(struct tblentry *cmdp, int verbose) 278 { 279 int idx; 280 const char *path; 281 char *name; 282 283 if (cmdp->cmdtype == CMDNORMAL) { 284 idx = cmdp->param.index; 285 path = pathval(); 286 do { 287 name = padvance(&path, cmdp->cmdname); 288 stunalloc(name); 289 } while (--idx >= 0); 290 out1str(name); 291 } else if (cmdp->cmdtype == CMDBUILTIN) { 292 out1fmt("builtin %s", cmdp->cmdname); 293 } else if (cmdp->cmdtype == CMDFUNCTION) { 294 out1fmt("function %s", cmdp->cmdname); 295 if (verbose) { 296 INTOFF; 297 name = commandtext(getfuncnode(cmdp->param.func)); 298 out1c(' '); 299 out1str(name); 300 ckfree(name); 301 INTON; 302 } 303 #ifdef DEBUG 304 } else { 305 error("internal error: cmdtype %d", cmdp->cmdtype); 306 #endif 307 } 308 if (cmdp->rehash) 309 out1c('*'); 310 out1c('\n'); 311 } 312 313 314 315 /* 316 * Resolve a command name. If you change this routine, you may have to 317 * change the shellexec routine as well. 318 */ 319 320 void 321 find_command(const char *name, struct cmdentry *entry, int act, 322 const char *path) 323 { 324 struct tblentry *cmdp, loc_cmd; 325 int idx; 326 int prev; 327 char *fullname; 328 struct stat statb; 329 int e; 330 int i; 331 int spec; 332 333 /* If name contains a slash, don't use the hash table */ 334 if (strchr(name, '/') != NULL) { 335 entry->cmdtype = CMDNORMAL; 336 entry->u.index = 0; 337 return; 338 } 339 340 /* If name is in the table, and not invalidated by cd, we're done */ 341 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) { 342 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC) 343 cmdp = NULL; 344 else 345 goto success; 346 } 347 348 /* Check for builtin next */ 349 if ((i = find_builtin(name, &spec)) >= 0) { 350 INTOFF; 351 cmdp = cmdlookup(name, 1); 352 if (cmdp->cmdtype == CMDFUNCTION) 353 cmdp = &loc_cmd; 354 cmdp->cmdtype = CMDBUILTIN; 355 cmdp->param.index = i; 356 cmdp->special = spec; 357 INTON; 358 goto success; 359 } 360 361 /* We have to search path. */ 362 prev = -1; /* where to start */ 363 if (cmdp) { /* doing a rehash */ 364 if (cmdp->cmdtype == CMDBUILTIN) 365 prev = -1; 366 else 367 prev = cmdp->param.index; 368 } 369 370 e = ENOENT; 371 idx = -1; 372 loop: 373 while ((fullname = padvance(&path, name)) != NULL) { 374 stunalloc(fullname); 375 idx++; 376 if (pathopt) { 377 if (prefix("func", pathopt)) { 378 /* handled below */ 379 } else { 380 goto loop; /* ignore unimplemented options */ 381 } 382 } 383 /* if rehash, don't redo absolute path names */ 384 if (fullname[0] == '/' && idx <= prev) { 385 if (idx < prev) 386 goto loop; 387 TRACE(("searchexec \"%s\": no change\n", name)); 388 goto success; 389 } 390 if (stat(fullname, &statb) < 0) { 391 if (errno != ENOENT && errno != ENOTDIR) 392 e = errno; 393 goto loop; 394 } 395 e = EACCES; /* if we fail, this will be the error */ 396 if (!S_ISREG(statb.st_mode)) 397 goto loop; 398 if (pathopt) { /* this is a %func directory */ 399 stalloc(strlen(fullname) + 1); 400 readcmdfile(fullname); 401 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 402 error("%s not defined in %s", name, fullname); 403 stunalloc(fullname); 404 goto success; 405 } 406 #ifdef notdef 407 if (statb.st_uid == geteuid()) { 408 if ((statb.st_mode & 0100) == 0) 409 goto loop; 410 } else if (statb.st_gid == getegid()) { 411 if ((statb.st_mode & 010) == 0) 412 goto loop; 413 } else { 414 if ((statb.st_mode & 01) == 0) 415 goto loop; 416 } 417 #endif 418 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 419 INTOFF; 420 cmdp = cmdlookup(name, 1); 421 if (cmdp->cmdtype == CMDFUNCTION) 422 cmdp = &loc_cmd; 423 cmdp->cmdtype = CMDNORMAL; 424 cmdp->param.index = idx; 425 INTON; 426 goto success; 427 } 428 429 /* We failed. If there was an entry for this command, delete it */ 430 if (cmdp && cmdp->cmdtype != CMDFUNCTION) 431 delete_cmd_entry(); 432 if (act & DO_ERR) { 433 if (e == ENOENT || e == ENOTDIR) 434 outfmt(out2, "%s: not found\n", name); 435 else 436 outfmt(out2, "%s: %s\n", name, strerror(e)); 437 } 438 entry->cmdtype = CMDUNKNOWN; 439 entry->u.index = 0; 440 return; 441 442 success: 443 cmdp->rehash = 0; 444 entry->cmdtype = cmdp->cmdtype; 445 entry->u = cmdp->param; 446 entry->special = cmdp->special; 447 } 448 449 450 451 /* 452 * Search the table of builtin commands. 453 */ 454 455 int 456 find_builtin(const char *name, int *special) 457 { 458 const struct builtincmd *bp; 459 460 for (bp = builtincmd ; bp->name ; bp++) { 461 if (*bp->name == *name && equal(bp->name, name)) { 462 *special = bp->special; 463 return bp->code; 464 } 465 } 466 return -1; 467 } 468 469 470 471 /* 472 * Called when a cd is done. Marks all commands so the next time they 473 * are executed they will be rehashed. 474 */ 475 476 void 477 hashcd(void) 478 { 479 struct tblentry **pp; 480 struct tblentry *cmdp; 481 482 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 483 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 484 if (cmdp->cmdtype == CMDNORMAL) 485 cmdp->rehash = 1; 486 } 487 } 488 } 489 490 491 492 /* 493 * Called before PATH is changed. The argument is the new value of PATH; 494 * pathval() still returns the old value at this point. Called with 495 * interrupts off. 496 */ 497 498 void 499 changepath(const char *newval __unused) 500 { 501 clearcmdentry(); 502 } 503 504 505 /* 506 * Clear out command entries. The argument specifies the first entry in 507 * PATH which has changed. 508 */ 509 510 void 511 clearcmdentry(void) 512 { 513 struct tblentry **tblp; 514 struct tblentry **pp; 515 struct tblentry *cmdp; 516 517 INTOFF; 518 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 519 pp = tblp; 520 while ((cmdp = *pp) != NULL) { 521 if (cmdp->cmdtype == CMDNORMAL) { 522 *pp = cmdp->next; 523 ckfree(cmdp); 524 } else { 525 pp = &cmdp->next; 526 } 527 } 528 } 529 INTON; 530 } 531 532 533 /* 534 * Locate a command in the command hash table. If "add" is nonzero, 535 * add the command to the table if it is not already present. The 536 * variable "lastcmdentry" is set to point to the address of the link 537 * pointing to the entry, so that delete_cmd_entry can delete the 538 * entry. 539 */ 540 541 static struct tblentry **lastcmdentry; 542 543 544 static struct tblentry * 545 cmdlookup(const char *name, int add) 546 { 547 int hashval; 548 const char *p; 549 struct tblentry *cmdp; 550 struct tblentry **pp; 551 552 p = name; 553 hashval = *p << 4; 554 while (*p) 555 hashval += *p++; 556 hashval &= 0x7FFF; 557 pp = &cmdtable[hashval % CMDTABLESIZE]; 558 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 559 if (equal(cmdp->cmdname, name)) 560 break; 561 pp = &cmdp->next; 562 } 563 if (add && cmdp == NULL) { 564 INTOFF; 565 cmdp = *pp = ckmalloc(sizeof (struct tblentry) 566 + strlen(name) + 1); 567 cmdp->next = NULL; 568 cmdp->cmdtype = CMDUNKNOWN; 569 cmdp->rehash = 0; 570 strcpy(cmdp->cmdname, name); 571 INTON; 572 } 573 lastcmdentry = pp; 574 return cmdp; 575 } 576 577 /* 578 * Delete the command entry returned on the last lookup. 579 */ 580 581 static void 582 delete_cmd_entry(void) 583 { 584 struct tblentry *cmdp; 585 586 INTOFF; 587 cmdp = *lastcmdentry; 588 *lastcmdentry = cmdp->next; 589 ckfree(cmdp); 590 INTON; 591 } 592 593 594 595 /* 596 * Add a new command entry, replacing any existing command entry for 597 * the same name. 598 */ 599 600 static void 601 addcmdentry(const char *name, struct cmdentry *entry) 602 { 603 struct tblentry *cmdp; 604 605 INTOFF; 606 cmdp = cmdlookup(name, 1); 607 if (cmdp->cmdtype == CMDFUNCTION) { 608 unreffunc(cmdp->param.func); 609 } 610 cmdp->cmdtype = entry->cmdtype; 611 cmdp->param = entry->u; 612 INTON; 613 } 614 615 616 /* 617 * Define a shell function. 618 */ 619 620 void 621 defun(const char *name, union node *func) 622 { 623 struct cmdentry entry; 624 625 INTOFF; 626 entry.cmdtype = CMDFUNCTION; 627 entry.u.func = copyfunc(func); 628 addcmdentry(name, &entry); 629 INTON; 630 } 631 632 633 /* 634 * Delete a function if it exists. 635 */ 636 637 int 638 unsetfunc(const char *name) 639 { 640 struct tblentry *cmdp; 641 642 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 643 unreffunc(cmdp->param.func); 644 delete_cmd_entry(); 645 return (0); 646 } 647 return (0); 648 } 649 650 651 /* 652 * Check if a function by a certain name exists. 653 */ 654 int 655 isfunc(const char *name) 656 { 657 struct tblentry *cmdp; 658 cmdp = cmdlookup(name, 0); 659 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION); 660 } 661 662 663 /* 664 * Shared code for the following builtin commands: 665 * type, command -v, command -V 666 */ 667 668 int 669 typecmd_impl(int argc, char **argv, int cmd, const char *path) 670 { 671 struct cmdentry entry; 672 struct tblentry *cmdp; 673 const char *const *pp; 674 struct alias *ap; 675 int i; 676 int error1 = 0; 677 678 if (path != pathval()) 679 clearcmdentry(); 680 681 for (i = 1; i < argc; i++) { 682 /* First look at the keywords */ 683 for (pp = parsekwd; *pp; pp++) 684 if (**pp == *argv[i] && equal(*pp, argv[i])) 685 break; 686 687 if (*pp) { 688 if (cmd == TYPECMD_SMALLV) 689 out1fmt("%s\n", argv[i]); 690 else 691 out1fmt("%s is a shell keyword\n", argv[i]); 692 continue; 693 } 694 695 /* Then look at the aliases */ 696 if ((ap = lookupalias(argv[i], 1)) != NULL) { 697 if (cmd == TYPECMD_SMALLV) 698 out1fmt("alias %s='%s'\n", argv[i], ap->val); 699 else 700 out1fmt("%s is an alias for %s\n", argv[i], 701 ap->val); 702 continue; 703 } 704 705 /* Then check if it is a tracked alias */ 706 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) { 707 entry.cmdtype = cmdp->cmdtype; 708 entry.u = cmdp->param; 709 entry.special = cmdp->special; 710 } 711 else { 712 /* Finally use brute force */ 713 find_command(argv[i], &entry, 0, path); 714 } 715 716 switch (entry.cmdtype) { 717 case CMDNORMAL: { 718 if (strchr(argv[i], '/') == NULL) { 719 const char *path2 = path; 720 char *name; 721 int j = entry.u.index; 722 do { 723 name = padvance(&path2, argv[i]); 724 stunalloc(name); 725 } while (--j >= 0); 726 if (cmd == TYPECMD_SMALLV) 727 out1fmt("%s\n", name); 728 else 729 out1fmt("%s is%s %s\n", argv[i], 730 (cmdp && cmd == TYPECMD_TYPE) ? 731 " a tracked alias for" : "", 732 name); 733 } else { 734 if (eaccess(argv[i], X_OK) == 0) { 735 if (cmd == TYPECMD_SMALLV) 736 out1fmt("%s\n", argv[i]); 737 else 738 out1fmt("%s is %s\n", argv[i], 739 argv[i]); 740 } else { 741 if (cmd != TYPECMD_SMALLV) 742 outfmt(out2, "%s: %s\n", 743 argv[i], strerror(errno)); 744 error1 |= 127; 745 } 746 } 747 break; 748 } 749 case CMDFUNCTION: 750 if (cmd == TYPECMD_SMALLV) 751 out1fmt("%s\n", argv[i]); 752 else 753 out1fmt("%s is a shell function\n", argv[i]); 754 break; 755 756 case CMDBUILTIN: 757 if (cmd == TYPECMD_SMALLV) 758 out1fmt("%s\n", argv[i]); 759 else if (entry.special) 760 out1fmt("%s is a special shell builtin\n", 761 argv[i]); 762 else 763 out1fmt("%s is a shell builtin\n", argv[i]); 764 break; 765 766 default: 767 if (cmd != TYPECMD_SMALLV) 768 outfmt(out2, "%s: not found\n", argv[i]); 769 error1 |= 127; 770 break; 771 } 772 } 773 774 if (path != pathval()) 775 clearcmdentry(); 776 777 return error1; 778 } 779 780 /* 781 * Locate and print what a word is... 782 */ 783 784 int 785 typecmd(int argc, char **argv) 786 { 787 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1)); 788 } 789