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. 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 "mystring.h" 74 #include "show.h" 75 #include "jobs.h" 76 #include "alias.h" 77 78 79 #define CMDTABLESIZE 31 /* should be prime */ 80 81 82 83 struct tblentry { 84 struct tblentry *next; /* next entry in hash chain */ 85 union param param; /* definition of builtin function */ 86 int special; /* flag for special builtin commands */ 87 signed char cmdtype; /* index identifying command */ 88 char cmdname[]; /* name of command */ 89 }; 90 91 92 static struct tblentry *cmdtable[CMDTABLESIZE]; 93 static int cmdtable_cd = 0; /* cmdtable contains cd-dependent entries */ 94 int exerrno = 0; /* Last exec error */ 95 96 97 static void tryexec(char *, char **, char **); 98 static void printentry(struct tblentry *, int); 99 static struct tblentry *cmdlookup(const char *, int); 100 static void delete_cmd_entry(void); 101 static void addcmdentry(const char *, struct cmdentry *); 102 103 104 105 /* 106 * Exec a program. Never returns. If you change this routine, you may 107 * have to change the find_command routine as well. 108 * 109 * The argv array may be changed and element argv[-1] should be writable. 110 */ 111 112 void 113 shellexec(char **argv, char **envp, const char *path, int idx) 114 { 115 char *cmdname; 116 int e; 117 118 if (strchr(argv[0], '/') != NULL) { 119 tryexec(argv[0], argv, envp); 120 e = errno; 121 } else { 122 e = ENOENT; 123 while ((cmdname = padvance(&path, argv[0])) != NULL) { 124 if (--idx < 0 && pathopt == NULL) { 125 tryexec(cmdname, argv, envp); 126 if (errno != ENOENT && errno != ENOTDIR) 127 e = errno; 128 if (e == ENOEXEC) 129 break; 130 } 131 stunalloc(cmdname); 132 } 133 } 134 135 /* Map to POSIX errors */ 136 if (e == ENOENT || e == ENOTDIR) { 137 exerrno = 127; 138 exerror(EXEXEC, "%s: not found", argv[0]); 139 } else { 140 exerrno = 126; 141 exerror(EXEXEC, "%s: %s", argv[0], strerror(e)); 142 } 143 } 144 145 146 static void 147 tryexec(char *cmd, char **argv, char **envp) 148 { 149 int e, in; 150 ssize_t n; 151 char buf[256]; 152 153 execve(cmd, argv, envp); 154 e = errno; 155 if (e == ENOEXEC) { 156 INTOFF; 157 in = open(cmd, O_RDONLY | O_NONBLOCK); 158 if (in != -1) { 159 n = pread(in, buf, sizeof buf, 0); 160 close(in); 161 if (n > 0 && memchr(buf, '\0', n) != NULL) { 162 errno = ENOEXEC; 163 return; 164 } 165 } 166 *argv = cmd; 167 *--argv = __DECONST(char *, _PATH_BSHELL); 168 execve(_PATH_BSHELL, argv, envp); 169 } 170 errno = e; 171 } 172 173 /* 174 * Do a path search. The variable path (passed by reference) should be 175 * set to the start of the path before the first call; padvance will update 176 * this value as it proceeds. Successive calls to padvance will return 177 * the possible path expansions in sequence. If an option (indicated by 178 * a percent sign) appears in the path entry then the global variable 179 * pathopt will be set to point to it; otherwise pathopt will be set to 180 * NULL. 181 */ 182 183 const char *pathopt; 184 185 char * 186 padvance(const char **path, const char *name) 187 { 188 const char *p, *start; 189 char *q; 190 size_t len, namelen; 191 192 if (*path == NULL) 193 return NULL; 194 start = *path; 195 for (p = start; *p && *p != ':' && *p != '%'; p++) 196 ; /* nothing */ 197 namelen = strlen(name); 198 len = p - start + namelen + 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 memcpy(q, name, namelen + 1); 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 out1c('\n'); 309 } 310 311 312 313 /* 314 * Resolve a command name. If you change this routine, you may have to 315 * change the shellexec routine as well. 316 */ 317 318 void 319 find_command(const char *name, struct cmdentry *entry, int act, 320 const char *path) 321 { 322 struct tblentry *cmdp, loc_cmd; 323 int idx; 324 char *fullname; 325 struct stat statb; 326 int e; 327 int i; 328 int spec; 329 int cd; 330 331 /* If name contains a slash, don't use the hash table */ 332 if (strchr(name, '/') != NULL) { 333 entry->cmdtype = CMDNORMAL; 334 entry->u.index = 0; 335 entry->special = 0; 336 return; 337 } 338 339 cd = 0; 340 341 /* If name is in the table, we're done */ 342 if ((cmdp = cmdlookup(name, 0)) != NULL) { 343 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC) 344 cmdp = NULL; 345 else 346 goto success; 347 } 348 349 /* Check for builtin next */ 350 if ((i = find_builtin(name, &spec)) >= 0) { 351 INTOFF; 352 cmdp = cmdlookup(name, 1); 353 if (cmdp->cmdtype == CMDFUNCTION) 354 cmdp = &loc_cmd; 355 cmdp->cmdtype = CMDBUILTIN; 356 cmdp->param.index = i; 357 cmdp->special = spec; 358 INTON; 359 goto success; 360 } 361 362 /* We have to search path. */ 363 364 e = ENOENT; 365 idx = -1; 366 for (;(fullname = padvance(&path, name)) != NULL; stunalloc(fullname)) { 367 idx++; 368 if (pathopt) { 369 if (strncmp(pathopt, "func", 4) == 0) { 370 /* handled below */ 371 } else { 372 continue; /* ignore unimplemented options */ 373 } 374 } 375 if (fullname[0] != '/') 376 cd = 1; 377 if (stat(fullname, &statb) < 0) { 378 if (errno != ENOENT && errno != ENOTDIR) 379 e = errno; 380 continue; 381 } 382 e = EACCES; /* if we fail, this will be the error */ 383 if (!S_ISREG(statb.st_mode)) 384 continue; 385 if (pathopt) { /* this is a %func directory */ 386 readcmdfile(fullname); 387 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 388 error("%s not defined in %s", name, fullname); 389 stunalloc(fullname); 390 goto success; 391 } 392 #ifdef notdef 393 if (statb.st_uid == geteuid()) { 394 if ((statb.st_mode & 0100) == 0) 395 goto loop; 396 } else if (statb.st_gid == getegid()) { 397 if ((statb.st_mode & 010) == 0) 398 goto loop; 399 } else { 400 if ((statb.st_mode & 01) == 0) 401 goto loop; 402 } 403 #endif 404 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 405 INTOFF; 406 stunalloc(fullname); 407 cmdp = cmdlookup(name, 1); 408 if (cmdp->cmdtype == CMDFUNCTION) 409 cmdp = &loc_cmd; 410 cmdp->cmdtype = CMDNORMAL; 411 cmdp->param.index = idx; 412 cmdp->special = 0; 413 INTON; 414 goto success; 415 } 416 417 if (act & DO_ERR) { 418 if (e == ENOENT || e == ENOTDIR) 419 outfmt(out2, "%s: not found\n", name); 420 else 421 outfmt(out2, "%s: %s\n", name, strerror(e)); 422 } 423 entry->cmdtype = CMDUNKNOWN; 424 entry->u.index = 0; 425 entry->special = 0; 426 return; 427 428 success: 429 if (cd) 430 cmdtable_cd = 1; 431 entry->cmdtype = cmdp->cmdtype; 432 entry->u = cmdp->param; 433 entry->special = cmdp->special; 434 } 435 436 437 438 /* 439 * Search the table of builtin commands. 440 */ 441 442 int 443 find_builtin(const char *name, int *special) 444 { 445 const unsigned char *bp; 446 size_t len; 447 448 len = strlen(name); 449 for (bp = builtincmd ; *bp ; bp += 2 + bp[0]) { 450 if (bp[0] == len && memcmp(bp + 2, name, len) == 0) { 451 *special = (bp[1] & BUILTIN_SPECIAL) != 0; 452 return bp[1] & ~BUILTIN_SPECIAL; 453 } 454 } 455 return -1; 456 } 457 458 459 460 /* 461 * Called when a cd is done. If any entry in cmdtable depends on the current 462 * directory, simply clear cmdtable completely. 463 */ 464 465 void 466 hashcd(void) 467 { 468 if (cmdtable_cd) 469 clearcmdentry(); 470 } 471 472 473 474 /* 475 * Called before PATH is changed. The argument is the new value of PATH; 476 * pathval() still returns the old value at this point. Called with 477 * interrupts off. 478 */ 479 480 void 481 changepath(const char *newval __unused) 482 { 483 clearcmdentry(); 484 } 485 486 487 /* 488 * Clear out cached utility locations. 489 */ 490 491 void 492 clearcmdentry(void) 493 { 494 struct tblentry **tblp; 495 struct tblentry **pp; 496 struct tblentry *cmdp; 497 498 INTOFF; 499 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 500 pp = tblp; 501 while ((cmdp = *pp) != NULL) { 502 if (cmdp->cmdtype == CMDNORMAL) { 503 *pp = cmdp->next; 504 ckfree(cmdp); 505 } else { 506 pp = &cmdp->next; 507 } 508 } 509 } 510 cmdtable_cd = 0; 511 INTON; 512 } 513 514 515 /* 516 * Locate a command in the command hash table. If "add" is nonzero, 517 * add the command to the table if it is not already present. The 518 * variable "lastcmdentry" is set to point to the address of the link 519 * pointing to the entry, so that delete_cmd_entry can delete the 520 * entry. 521 */ 522 523 static struct tblentry **lastcmdentry; 524 525 526 static struct tblentry * 527 cmdlookup(const char *name, int add) 528 { 529 unsigned int hashval; 530 const char *p; 531 struct tblentry *cmdp; 532 struct tblentry **pp; 533 size_t len; 534 535 p = name; 536 hashval = (unsigned char)*p << 4; 537 while (*p) 538 hashval += *p++; 539 pp = &cmdtable[hashval % CMDTABLESIZE]; 540 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 541 if (equal(cmdp->cmdname, name)) 542 break; 543 pp = &cmdp->next; 544 } 545 if (add && cmdp == NULL) { 546 INTOFF; 547 len = strlen(name); 548 cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1); 549 cmdp->next = NULL; 550 cmdp->cmdtype = CMDUNKNOWN; 551 memcpy(cmdp->cmdname, name, len + 1); 552 INTON; 553 } 554 lastcmdentry = pp; 555 return cmdp; 556 } 557 558 /* 559 * Delete the command entry returned on the last lookup. 560 */ 561 562 static void 563 delete_cmd_entry(void) 564 { 565 struct tblentry *cmdp; 566 567 INTOFF; 568 cmdp = *lastcmdentry; 569 *lastcmdentry = cmdp->next; 570 ckfree(cmdp); 571 INTON; 572 } 573 574 575 576 /* 577 * Add a new command entry, replacing any existing command entry for 578 * the same name. 579 */ 580 581 static void 582 addcmdentry(const char *name, struct cmdentry *entry) 583 { 584 struct tblentry *cmdp; 585 586 INTOFF; 587 cmdp = cmdlookup(name, 1); 588 if (cmdp->cmdtype == CMDFUNCTION) { 589 unreffunc(cmdp->param.func); 590 } 591 cmdp->cmdtype = entry->cmdtype; 592 cmdp->param = entry->u; 593 cmdp->special = entry->special; 594 INTON; 595 } 596 597 598 /* 599 * Define a shell function. 600 */ 601 602 void 603 defun(const char *name, union node *func) 604 { 605 struct cmdentry entry; 606 607 INTOFF; 608 entry.cmdtype = CMDFUNCTION; 609 entry.u.func = copyfunc(func); 610 entry.special = 0; 611 addcmdentry(name, &entry); 612 INTON; 613 } 614 615 616 /* 617 * Delete a function if it exists. 618 * Called with interrupts off. 619 */ 620 621 int 622 unsetfunc(const char *name) 623 { 624 struct tblentry *cmdp; 625 626 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 627 unreffunc(cmdp->param.func); 628 delete_cmd_entry(); 629 return (0); 630 } 631 return (0); 632 } 633 634 635 /* 636 * Check if a function by a certain name exists. 637 */ 638 int 639 isfunc(const char *name) 640 { 641 struct tblentry *cmdp; 642 cmdp = cmdlookup(name, 0); 643 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION); 644 } 645 646 647 /* 648 * Shared code for the following builtin commands: 649 * type, command -v, command -V 650 */ 651 652 int 653 typecmd_impl(int argc, char **argv, int cmd, const char *path) 654 { 655 struct cmdentry entry; 656 struct tblentry *cmdp; 657 const char *const *pp; 658 struct alias *ap; 659 int i; 660 int error1 = 0; 661 662 if (path != pathval()) 663 clearcmdentry(); 664 665 for (i = 1; i < argc; i++) { 666 /* First look at the keywords */ 667 for (pp = parsekwd; *pp; pp++) 668 if (**pp == *argv[i] && equal(*pp, argv[i])) 669 break; 670 671 if (*pp) { 672 if (cmd == TYPECMD_SMALLV) 673 out1fmt("%s\n", argv[i]); 674 else 675 out1fmt("%s is a shell keyword\n", argv[i]); 676 continue; 677 } 678 679 /* Then look at the aliases */ 680 if ((ap = lookupalias(argv[i], 1)) != NULL) { 681 if (cmd == TYPECMD_SMALLV) { 682 out1fmt("alias %s=", argv[i]); 683 out1qstr(ap->val); 684 outcslow('\n', out1); 685 } else 686 out1fmt("%s is an alias for %s\n", argv[i], 687 ap->val); 688 continue; 689 } 690 691 /* Then check if it is a tracked alias */ 692 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) { 693 entry.cmdtype = cmdp->cmdtype; 694 entry.u = cmdp->param; 695 entry.special = cmdp->special; 696 } 697 else { 698 /* Finally use brute force */ 699 find_command(argv[i], &entry, 0, path); 700 } 701 702 switch (entry.cmdtype) { 703 case CMDNORMAL: { 704 if (strchr(argv[i], '/') == NULL) { 705 const char *path2 = path; 706 char *name; 707 int j = entry.u.index; 708 do { 709 name = padvance(&path2, argv[i]); 710 stunalloc(name); 711 } while (--j >= 0); 712 if (cmd == TYPECMD_SMALLV) 713 out1fmt("%s\n", name); 714 else 715 out1fmt("%s is%s %s\n", argv[i], 716 (cmdp && cmd == TYPECMD_TYPE) ? 717 " a tracked alias for" : "", 718 name); 719 } else { 720 if (eaccess(argv[i], X_OK) == 0) { 721 if (cmd == TYPECMD_SMALLV) 722 out1fmt("%s\n", argv[i]); 723 else 724 out1fmt("%s is %s\n", argv[i], 725 argv[i]); 726 } else { 727 if (cmd != TYPECMD_SMALLV) 728 outfmt(out2, "%s: %s\n", 729 argv[i], strerror(errno)); 730 error1 |= 127; 731 } 732 } 733 break; 734 } 735 case CMDFUNCTION: 736 if (cmd == TYPECMD_SMALLV) 737 out1fmt("%s\n", argv[i]); 738 else 739 out1fmt("%s is a shell function\n", argv[i]); 740 break; 741 742 case CMDBUILTIN: 743 if (cmd == TYPECMD_SMALLV) 744 out1fmt("%s\n", argv[i]); 745 else if (entry.special) 746 out1fmt("%s is a special shell builtin\n", 747 argv[i]); 748 else 749 out1fmt("%s is a shell builtin\n", argv[i]); 750 break; 751 752 default: 753 if (cmd != TYPECMD_SMALLV) 754 outfmt(out2, "%s: not found\n", argv[i]); 755 error1 |= 127; 756 break; 757 } 758 } 759 760 if (path != pathval()) 761 clearcmdentry(); 762 763 return error1; 764 } 765 766 /* 767 * Locate and print what a word is... 768 */ 769 770 int 771 typecmd(int argc, char **argv) 772 { 773 if (argc > 2 && strcmp(argv[1], "--") == 0) 774 argc--, argv++; 775 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1)); 776 } 777