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 const char *opt; 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, &opt, argv[0])) != NULL) { 125 if (--idx < 0 && opt == 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 = __DECONST(char *, _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 popt is not NULL, options 179 * are processed: if an option (indicated by a percent sign) appears in 180 * the path entry then *popt will be set to point to it; else *popt will be 181 * set to NULL. If popt is NULL, percent signs are not special. 182 */ 183 184 char * 185 padvance(const char **path, const char **popt, const char *name) 186 { 187 const char *p, *start; 188 char *q; 189 size_t len, namelen; 190 191 if (*path == NULL) 192 return NULL; 193 start = *path; 194 if (popt != NULL) 195 for (p = start; *p && *p != ':' && *p != '%'; p++) 196 ; /* nothing */ 197 else 198 for (p = start; *p && *p != ':'; p++) 199 ; /* nothing */ 200 namelen = strlen(name); 201 len = p - start + namelen + 2; /* "2" is for '/' and '\0' */ 202 STARTSTACKSTR(q); 203 CHECKSTRSPACE(len, q); 204 if (p != start) { 205 memcpy(q, start, p - start); 206 q += p - start; 207 *q++ = '/'; 208 } 209 memcpy(q, name, namelen + 1); 210 if (popt != NULL) { 211 if (*p == '%') { 212 *popt = ++p; 213 while (*p && *p != ':') p++; 214 } else 215 *popt = NULL; 216 } 217 if (*p == ':') 218 *path = p + 1; 219 else 220 *path = NULL; 221 return stalloc(len); 222 } 223 224 225 226 /*** Command hashing code ***/ 227 228 229 int 230 hashcmd(int argc __unused, char **argv __unused) 231 { 232 struct tblentry **pp; 233 struct tblentry *cmdp; 234 int c; 235 int verbose; 236 struct cmdentry entry; 237 char *name; 238 int errors; 239 240 errors = 0; 241 verbose = 0; 242 while ((c = nextopt("rv")) != '\0') { 243 if (c == 'r') { 244 clearcmdentry(); 245 } else if (c == 'v') { 246 verbose++; 247 } 248 } 249 if (*argptr == NULL) { 250 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 251 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 252 if (cmdp->cmdtype == CMDNORMAL) 253 printentry(cmdp, verbose); 254 } 255 } 256 return 0; 257 } 258 while ((name = *argptr) != NULL) { 259 if ((cmdp = cmdlookup(name, 0)) != NULL 260 && cmdp->cmdtype == CMDNORMAL) 261 delete_cmd_entry(); 262 find_command(name, &entry, DO_ERR, pathval()); 263 if (entry.cmdtype == CMDUNKNOWN) 264 errors = 1; 265 else if (verbose) { 266 cmdp = cmdlookup(name, 0); 267 if (cmdp != NULL) 268 printentry(cmdp, verbose); 269 else { 270 outfmt(out2, "%s: not found\n", name); 271 errors = 1; 272 } 273 flushall(); 274 } 275 argptr++; 276 } 277 return errors; 278 } 279 280 281 static void 282 printentry(struct tblentry *cmdp, int verbose) 283 { 284 int idx; 285 const char *path, *opt; 286 char *name; 287 288 if (cmdp->cmdtype == CMDNORMAL) { 289 idx = cmdp->param.index; 290 path = pathval(); 291 do { 292 name = padvance(&path, &opt, cmdp->cmdname); 293 stunalloc(name); 294 } while (--idx >= 0); 295 out1str(name); 296 } else if (cmdp->cmdtype == CMDBUILTIN) { 297 out1fmt("builtin %s", cmdp->cmdname); 298 } else if (cmdp->cmdtype == CMDFUNCTION) { 299 out1fmt("function %s", cmdp->cmdname); 300 if (verbose) { 301 INTOFF; 302 name = commandtext(getfuncnode(cmdp->param.func)); 303 out1c(' '); 304 out1str(name); 305 ckfree(name); 306 INTON; 307 } 308 #ifdef DEBUG 309 } else { 310 error("internal error: cmdtype %d", cmdp->cmdtype); 311 #endif 312 } 313 out1c('\n'); 314 } 315 316 317 318 /* 319 * Resolve a command name. If you change this routine, you may have to 320 * change the shellexec routine as well. 321 */ 322 323 void 324 find_command(const char *name, struct cmdentry *entry, int act, 325 const char *path) 326 { 327 struct tblentry *cmdp, loc_cmd; 328 int idx; 329 const char *opt; 330 char *fullname; 331 struct stat statb; 332 int e; 333 int i; 334 int spec; 335 int cd; 336 337 /* If name contains a slash, don't use the hash table */ 338 if (strchr(name, '/') != NULL) { 339 entry->cmdtype = CMDNORMAL; 340 entry->u.index = 0; 341 entry->special = 0; 342 return; 343 } 344 345 cd = 0; 346 347 /* If name is in the table, we're done */ 348 if ((cmdp = cmdlookup(name, 0)) != NULL) { 349 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC) 350 cmdp = NULL; 351 else 352 goto success; 353 } 354 355 /* Check for builtin next */ 356 if ((i = find_builtin(name, &spec)) >= 0) { 357 INTOFF; 358 cmdp = cmdlookup(name, 1); 359 if (cmdp->cmdtype == CMDFUNCTION) 360 cmdp = &loc_cmd; 361 cmdp->cmdtype = CMDBUILTIN; 362 cmdp->param.index = i; 363 cmdp->special = spec; 364 INTON; 365 goto success; 366 } 367 368 /* We have to search path. */ 369 370 e = ENOENT; 371 idx = -1; 372 for (;(fullname = padvance(&path, &opt, name)) != NULL; 373 stunalloc(fullname)) { 374 idx++; 375 if (opt) { 376 if (strncmp(opt, "func", 4) == 0) { 377 /* handled below */ 378 } else { 379 continue; /* ignore unimplemented options */ 380 } 381 } 382 if (fullname[0] != '/') 383 cd = 1; 384 if (stat(fullname, &statb) < 0) { 385 if (errno != ENOENT && errno != ENOTDIR) 386 e = errno; 387 continue; 388 } 389 e = EACCES; /* if we fail, this will be the error */ 390 if (!S_ISREG(statb.st_mode)) 391 continue; 392 if (opt) { /* this is a %func directory */ 393 readcmdfile(fullname); 394 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 395 error("%s not defined in %s", name, fullname); 396 stunalloc(fullname); 397 goto success; 398 } 399 #ifdef notdef 400 if (statb.st_uid == geteuid()) { 401 if ((statb.st_mode & 0100) == 0) 402 goto loop; 403 } else if (statb.st_gid == getegid()) { 404 if ((statb.st_mode & 010) == 0) 405 goto loop; 406 } else { 407 if ((statb.st_mode & 01) == 0) 408 goto loop; 409 } 410 #endif 411 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 412 INTOFF; 413 stunalloc(fullname); 414 cmdp = cmdlookup(name, 1); 415 if (cmdp->cmdtype == CMDFUNCTION) 416 cmdp = &loc_cmd; 417 cmdp->cmdtype = CMDNORMAL; 418 cmdp->param.index = idx; 419 cmdp->special = 0; 420 INTON; 421 goto success; 422 } 423 424 if (act & DO_ERR) { 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 entry->u.index = 0; 432 entry->special = 0; 433 return; 434 435 success: 436 if (cd) 437 cmdtable_cd = 1; 438 entry->cmdtype = cmdp->cmdtype; 439 entry->u = cmdp->param; 440 entry->special = cmdp->special; 441 } 442 443 444 445 /* 446 * Search the table of builtin commands. 447 */ 448 449 int 450 find_builtin(const char *name, int *special) 451 { 452 const unsigned char *bp; 453 size_t len; 454 455 len = strlen(name); 456 for (bp = builtincmd ; *bp ; bp += 2 + bp[0]) { 457 if (bp[0] == len && memcmp(bp + 2, name, len) == 0) { 458 *special = (bp[1] & BUILTIN_SPECIAL) != 0; 459 return bp[1] & ~BUILTIN_SPECIAL; 460 } 461 } 462 return -1; 463 } 464 465 466 467 /* 468 * Called when a cd is done. If any entry in cmdtable depends on the current 469 * directory, simply clear cmdtable completely. 470 */ 471 472 void 473 hashcd(void) 474 { 475 if (cmdtable_cd) 476 clearcmdentry(); 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 __unused) 489 { 490 clearcmdentry(); 491 } 492 493 494 /* 495 * Clear out cached utility locations. 496 */ 497 498 void 499 clearcmdentry(void) 500 { 501 struct tblentry **tblp; 502 struct tblentry **pp; 503 struct tblentry *cmdp; 504 505 INTOFF; 506 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 507 pp = tblp; 508 while ((cmdp = *pp) != NULL) { 509 if (cmdp->cmdtype == CMDNORMAL) { 510 *pp = cmdp->next; 511 ckfree(cmdp); 512 } else { 513 pp = &cmdp->next; 514 } 515 } 516 } 517 cmdtable_cd = 0; 518 INTON; 519 } 520 521 522 /* 523 * Locate a command in the command hash table. If "add" is nonzero, 524 * add the command to the table if it is not already present. The 525 * variable "lastcmdentry" is set to point to the address of the link 526 * pointing to the entry, so that delete_cmd_entry can delete the 527 * entry. 528 */ 529 530 static struct tblentry **lastcmdentry; 531 532 533 static struct tblentry * 534 cmdlookup(const char *name, int add) 535 { 536 unsigned int hashval; 537 const char *p; 538 struct tblentry *cmdp; 539 struct tblentry **pp; 540 size_t len; 541 542 p = name; 543 hashval = (unsigned char)*p << 4; 544 while (*p) 545 hashval += *p++; 546 pp = &cmdtable[hashval % CMDTABLESIZE]; 547 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 548 if (equal(cmdp->cmdname, name)) 549 break; 550 pp = &cmdp->next; 551 } 552 if (add && cmdp == NULL) { 553 INTOFF; 554 len = strlen(name); 555 cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1); 556 cmdp->next = NULL; 557 cmdp->cmdtype = CMDUNKNOWN; 558 memcpy(cmdp->cmdname, name, len + 1); 559 INTON; 560 } 561 lastcmdentry = pp; 562 return cmdp; 563 } 564 565 /* 566 * Delete the command entry returned on the last lookup. 567 */ 568 569 static void 570 delete_cmd_entry(void) 571 { 572 struct tblentry *cmdp; 573 574 INTOFF; 575 cmdp = *lastcmdentry; 576 *lastcmdentry = cmdp->next; 577 ckfree(cmdp); 578 INTON; 579 } 580 581 582 583 /* 584 * Add a new command entry, replacing any existing command entry for 585 * the same name. 586 */ 587 588 static void 589 addcmdentry(const char *name, struct cmdentry *entry) 590 { 591 struct tblentry *cmdp; 592 593 INTOFF; 594 cmdp = cmdlookup(name, 1); 595 if (cmdp->cmdtype == CMDFUNCTION) { 596 unreffunc(cmdp->param.func); 597 } 598 cmdp->cmdtype = entry->cmdtype; 599 cmdp->param = entry->u; 600 cmdp->special = entry->special; 601 INTON; 602 } 603 604 605 /* 606 * Define a shell function. 607 */ 608 609 void 610 defun(const char *name, union node *func) 611 { 612 struct cmdentry entry; 613 614 INTOFF; 615 entry.cmdtype = CMDFUNCTION; 616 entry.u.func = copyfunc(func); 617 entry.special = 0; 618 addcmdentry(name, &entry); 619 INTON; 620 } 621 622 623 /* 624 * Delete a function if it exists. 625 * Called with interrupts off. 626 */ 627 628 int 629 unsetfunc(const char *name) 630 { 631 struct tblentry *cmdp; 632 633 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 634 unreffunc(cmdp->param.func); 635 delete_cmd_entry(); 636 return (0); 637 } 638 return (0); 639 } 640 641 642 /* 643 * Check if a function by a certain name exists. 644 */ 645 int 646 isfunc(const char *name) 647 { 648 struct tblentry *cmdp; 649 cmdp = cmdlookup(name, 0); 650 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION); 651 } 652 653 654 /* 655 * Shared code for the following builtin commands: 656 * type, command -v, command -V 657 */ 658 659 int 660 typecmd_impl(int argc, char **argv, int cmd, const char *path) 661 { 662 struct cmdentry entry; 663 struct tblentry *cmdp; 664 const char *const *pp; 665 struct alias *ap; 666 int i; 667 int error1 = 0; 668 669 if (path != pathval()) 670 clearcmdentry(); 671 672 for (i = 1; i < argc; i++) { 673 /* First look at the keywords */ 674 for (pp = parsekwd; *pp; pp++) 675 if (**pp == *argv[i] && equal(*pp, argv[i])) 676 break; 677 678 if (*pp) { 679 if (cmd == TYPECMD_SMALLV) 680 out1fmt("%s\n", argv[i]); 681 else 682 out1fmt("%s is a shell keyword\n", argv[i]); 683 continue; 684 } 685 686 /* Then look at the aliases */ 687 if ((ap = lookupalias(argv[i], 1)) != NULL) { 688 if (cmd == TYPECMD_SMALLV) { 689 out1fmt("alias %s=", argv[i]); 690 out1qstr(ap->val); 691 outcslow('\n', out1); 692 } else 693 out1fmt("%s is an alias for %s\n", argv[i], 694 ap->val); 695 continue; 696 } 697 698 /* Then check if it is a tracked alias */ 699 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) { 700 entry.cmdtype = cmdp->cmdtype; 701 entry.u = cmdp->param; 702 entry.special = cmdp->special; 703 } 704 else { 705 /* Finally use brute force */ 706 find_command(argv[i], &entry, 0, path); 707 } 708 709 switch (entry.cmdtype) { 710 case CMDNORMAL: { 711 if (strchr(argv[i], '/') == NULL) { 712 const char *path2 = path; 713 const char *opt2; 714 char *name; 715 int j = entry.u.index; 716 do { 717 name = padvance(&path2, &opt2, argv[i]); 718 stunalloc(name); 719 } while (--j >= 0); 720 if (cmd == TYPECMD_SMALLV) 721 out1fmt("%s\n", name); 722 else 723 out1fmt("%s is%s %s\n", argv[i], 724 (cmdp && cmd == TYPECMD_TYPE) ? 725 " a tracked alias for" : "", 726 name); 727 } else { 728 if (eaccess(argv[i], X_OK) == 0) { 729 if (cmd == TYPECMD_SMALLV) 730 out1fmt("%s\n", argv[i]); 731 else 732 out1fmt("%s is %s\n", argv[i], 733 argv[i]); 734 } else { 735 if (cmd != TYPECMD_SMALLV) 736 outfmt(out2, "%s: %s\n", 737 argv[i], strerror(errno)); 738 error1 |= 127; 739 } 740 } 741 break; 742 } 743 case CMDFUNCTION: 744 if (cmd == TYPECMD_SMALLV) 745 out1fmt("%s\n", argv[i]); 746 else 747 out1fmt("%s is a shell function\n", argv[i]); 748 break; 749 750 case CMDBUILTIN: 751 if (cmd == TYPECMD_SMALLV) 752 out1fmt("%s\n", argv[i]); 753 else if (entry.special) 754 out1fmt("%s is a special shell builtin\n", 755 argv[i]); 756 else 757 out1fmt("%s is a shell builtin\n", argv[i]); 758 break; 759 760 default: 761 if (cmd != TYPECMD_SMALLV) 762 outfmt(out2, "%s: not found\n", argv[i]); 763 error1 |= 127; 764 break; 765 } 766 } 767 768 if (path != pathval()) 769 clearcmdentry(); 770 771 return error1; 772 } 773 774 /* 775 * Locate and print what a word is... 776 */ 777 778 int 779 typecmd(int argc, char **argv) 780 { 781 if (argc > 2 && strcmp(argv[1], "--") == 0) 782 argc--, argv++; 783 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1)); 784 } 785