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 "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, and not invalidated by cd, 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 command entries. The argument specifies the first entry in 489 * PATH which has changed. 490 */ 491 492 void 493 clearcmdentry(void) 494 { 495 struct tblentry **tblp; 496 struct tblentry **pp; 497 struct tblentry *cmdp; 498 499 INTOFF; 500 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 501 pp = tblp; 502 while ((cmdp = *pp) != NULL) { 503 if (cmdp->cmdtype == CMDNORMAL) { 504 *pp = cmdp->next; 505 ckfree(cmdp); 506 } else { 507 pp = &cmdp->next; 508 } 509 } 510 } 511 cmdtable_cd = 0; 512 INTON; 513 } 514 515 516 /* 517 * Locate a command in the command hash table. If "add" is nonzero, 518 * add the command to the table if it is not already present. The 519 * variable "lastcmdentry" is set to point to the address of the link 520 * pointing to the entry, so that delete_cmd_entry can delete the 521 * entry. 522 */ 523 524 static struct tblentry **lastcmdentry; 525 526 527 static struct tblentry * 528 cmdlookup(const char *name, int add) 529 { 530 unsigned int hashval; 531 const char *p; 532 struct tblentry *cmdp; 533 struct tblentry **pp; 534 size_t len; 535 536 p = name; 537 hashval = (unsigned char)*p << 4; 538 while (*p) 539 hashval += *p++; 540 pp = &cmdtable[hashval % CMDTABLESIZE]; 541 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 542 if (equal(cmdp->cmdname, name)) 543 break; 544 pp = &cmdp->next; 545 } 546 if (add && cmdp == NULL) { 547 INTOFF; 548 len = strlen(name); 549 cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1); 550 cmdp->next = NULL; 551 cmdp->cmdtype = CMDUNKNOWN; 552 memcpy(cmdp->cmdname, name, len + 1); 553 INTON; 554 } 555 lastcmdentry = pp; 556 return cmdp; 557 } 558 559 /* 560 * Delete the command entry returned on the last lookup. 561 */ 562 563 static void 564 delete_cmd_entry(void) 565 { 566 struct tblentry *cmdp; 567 568 INTOFF; 569 cmdp = *lastcmdentry; 570 *lastcmdentry = cmdp->next; 571 ckfree(cmdp); 572 INTON; 573 } 574 575 576 577 /* 578 * Add a new command entry, replacing any existing command entry for 579 * the same name. 580 */ 581 582 static void 583 addcmdentry(const char *name, struct cmdentry *entry) 584 { 585 struct tblentry *cmdp; 586 587 INTOFF; 588 cmdp = cmdlookup(name, 1); 589 if (cmdp->cmdtype == CMDFUNCTION) { 590 unreffunc(cmdp->param.func); 591 } 592 cmdp->cmdtype = entry->cmdtype; 593 cmdp->param = entry->u; 594 cmdp->special = entry->special; 595 INTON; 596 } 597 598 599 /* 600 * Define a shell function. 601 */ 602 603 void 604 defun(const char *name, union node *func) 605 { 606 struct cmdentry entry; 607 608 INTOFF; 609 entry.cmdtype = CMDFUNCTION; 610 entry.u.func = copyfunc(func); 611 entry.special = 0; 612 addcmdentry(name, &entry); 613 INTON; 614 } 615 616 617 /* 618 * Delete a function if it exists. 619 * Called with interrupts off. 620 */ 621 622 int 623 unsetfunc(const char *name) 624 { 625 struct tblentry *cmdp; 626 627 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 628 unreffunc(cmdp->param.func); 629 delete_cmd_entry(); 630 return (0); 631 } 632 return (0); 633 } 634 635 636 /* 637 * Check if a function by a certain name exists. 638 */ 639 int 640 isfunc(const char *name) 641 { 642 struct tblentry *cmdp; 643 cmdp = cmdlookup(name, 0); 644 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION); 645 } 646 647 648 /* 649 * Shared code for the following builtin commands: 650 * type, command -v, command -V 651 */ 652 653 int 654 typecmd_impl(int argc, char **argv, int cmd, const char *path) 655 { 656 struct cmdentry entry; 657 struct tblentry *cmdp; 658 const char *const *pp; 659 struct alias *ap; 660 int i; 661 int error1 = 0; 662 663 if (path != pathval()) 664 clearcmdentry(); 665 666 for (i = 1; i < argc; i++) { 667 /* First look at the keywords */ 668 for (pp = parsekwd; *pp; pp++) 669 if (**pp == *argv[i] && equal(*pp, argv[i])) 670 break; 671 672 if (*pp) { 673 if (cmd == TYPECMD_SMALLV) 674 out1fmt("%s\n", argv[i]); 675 else 676 out1fmt("%s is a shell keyword\n", argv[i]); 677 continue; 678 } 679 680 /* Then look at the aliases */ 681 if ((ap = lookupalias(argv[i], 1)) != NULL) { 682 if (cmd == TYPECMD_SMALLV) { 683 out1fmt("alias %s=", argv[i]); 684 out1qstr(ap->val); 685 outcslow('\n', out1); 686 } else 687 out1fmt("%s is an alias for %s\n", argv[i], 688 ap->val); 689 continue; 690 } 691 692 /* Then check if it is a tracked alias */ 693 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) { 694 entry.cmdtype = cmdp->cmdtype; 695 entry.u = cmdp->param; 696 entry.special = cmdp->special; 697 } 698 else { 699 /* Finally use brute force */ 700 find_command(argv[i], &entry, 0, path); 701 } 702 703 switch (entry.cmdtype) { 704 case CMDNORMAL: { 705 if (strchr(argv[i], '/') == NULL) { 706 const char *path2 = path; 707 char *name; 708 int j = entry.u.index; 709 do { 710 name = padvance(&path2, argv[i]); 711 stunalloc(name); 712 } while (--j >= 0); 713 if (cmd == TYPECMD_SMALLV) 714 out1fmt("%s\n", name); 715 else 716 out1fmt("%s is%s %s\n", argv[i], 717 (cmdp && cmd == TYPECMD_TYPE) ? 718 " a tracked alias for" : "", 719 name); 720 } else { 721 if (eaccess(argv[i], X_OK) == 0) { 722 if (cmd == TYPECMD_SMALLV) 723 out1fmt("%s\n", argv[i]); 724 else 725 out1fmt("%s is %s\n", argv[i], 726 argv[i]); 727 } else { 728 if (cmd != TYPECMD_SMALLV) 729 outfmt(out2, "%s: %s\n", 730 argv[i], strerror(errno)); 731 error1 |= 127; 732 } 733 } 734 break; 735 } 736 case CMDFUNCTION: 737 if (cmd == TYPECMD_SMALLV) 738 out1fmt("%s\n", argv[i]); 739 else 740 out1fmt("%s is a shell function\n", argv[i]); 741 break; 742 743 case CMDBUILTIN: 744 if (cmd == TYPECMD_SMALLV) 745 out1fmt("%s\n", argv[i]); 746 else if (entry.special) 747 out1fmt("%s is a special shell builtin\n", 748 argv[i]); 749 else 750 out1fmt("%s is a shell builtin\n", argv[i]); 751 break; 752 753 default: 754 if (cmd != TYPECMD_SMALLV) 755 outfmt(out2, "%s: not found\n", argv[i]); 756 error1 |= 127; 757 break; 758 } 759 } 760 761 if (path != pathval()) 762 clearcmdentry(); 763 764 return error1; 765 } 766 767 /* 768 * Locate and print what a word is... 769 */ 770 771 int 772 typecmd(int argc, char **argv) 773 { 774 if (argc > 2 && strcmp(argv[1], "--") == 0) 775 argc--, argv++; 776 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1)); 777 } 778