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 return; 336 } 337 338 cd = 0; 339 340 /* If name is in the table, and not invalidated by cd, we're done */ 341 if ((cmdp = cmdlookup(name, 0)) != NULL) { 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. */ 362 363 e = ENOENT; 364 idx = -1; 365 for (;(fullname = padvance(&path, name)) != NULL; stunalloc(fullname)) { 366 idx++; 367 if (pathopt) { 368 if (strncmp(pathopt, "func", 4) == 0) { 369 /* handled below */ 370 } else { 371 continue; /* ignore unimplemented options */ 372 } 373 } 374 if (fullname[0] != '/') 375 cd = 1; 376 if (stat(fullname, &statb) < 0) { 377 if (errno != ENOENT && errno != ENOTDIR) 378 e = errno; 379 continue; 380 } 381 e = EACCES; /* if we fail, this will be the error */ 382 if (!S_ISREG(statb.st_mode)) 383 continue; 384 if (pathopt) { /* this is a %func directory */ 385 readcmdfile(fullname); 386 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 387 error("%s not defined in %s", name, fullname); 388 stunalloc(fullname); 389 goto success; 390 } 391 #ifdef notdef 392 if (statb.st_uid == geteuid()) { 393 if ((statb.st_mode & 0100) == 0) 394 goto loop; 395 } else if (statb.st_gid == getegid()) { 396 if ((statb.st_mode & 010) == 0) 397 goto loop; 398 } else { 399 if ((statb.st_mode & 01) == 0) 400 goto loop; 401 } 402 #endif 403 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 404 INTOFF; 405 stunalloc(fullname); 406 cmdp = cmdlookup(name, 1); 407 if (cmdp->cmdtype == CMDFUNCTION) 408 cmdp = &loc_cmd; 409 cmdp->cmdtype = CMDNORMAL; 410 cmdp->param.index = idx; 411 INTON; 412 goto success; 413 } 414 415 if (act & DO_ERR) { 416 if (e == ENOENT || e == ENOTDIR) 417 outfmt(out2, "%s: not found\n", name); 418 else 419 outfmt(out2, "%s: %s\n", name, strerror(e)); 420 } 421 entry->cmdtype = CMDUNKNOWN; 422 entry->u.index = 0; 423 return; 424 425 success: 426 if (cd) 427 cmdtable_cd = 1; 428 entry->cmdtype = cmdp->cmdtype; 429 entry->u = cmdp->param; 430 entry->special = cmdp->special; 431 } 432 433 434 435 /* 436 * Search the table of builtin commands. 437 */ 438 439 int 440 find_builtin(const char *name, int *special) 441 { 442 const struct builtincmd *bp; 443 444 for (bp = builtincmd ; bp->name ; bp++) { 445 if (*bp->name == *name && equal(bp->name, name)) { 446 *special = bp->special; 447 return bp->code; 448 } 449 } 450 return -1; 451 } 452 453 454 455 /* 456 * Called when a cd is done. If any entry in cmdtable depends on the current 457 * directory, simply clear cmdtable completely. 458 */ 459 460 void 461 hashcd(void) 462 { 463 if (cmdtable_cd) 464 clearcmdentry(); 465 } 466 467 468 469 /* 470 * Called before PATH is changed. The argument is the new value of PATH; 471 * pathval() still returns the old value at this point. Called with 472 * interrupts off. 473 */ 474 475 void 476 changepath(const char *newval __unused) 477 { 478 clearcmdentry(); 479 } 480 481 482 /* 483 * Clear out command entries. The argument specifies the first entry in 484 * PATH which has changed. 485 */ 486 487 void 488 clearcmdentry(void) 489 { 490 struct tblentry **tblp; 491 struct tblentry **pp; 492 struct tblentry *cmdp; 493 494 INTOFF; 495 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 496 pp = tblp; 497 while ((cmdp = *pp) != NULL) { 498 if (cmdp->cmdtype == CMDNORMAL) { 499 *pp = cmdp->next; 500 ckfree(cmdp); 501 } else { 502 pp = &cmdp->next; 503 } 504 } 505 } 506 cmdtable_cd = 0; 507 INTON; 508 } 509 510 511 /* 512 * Locate a command in the command hash table. If "add" is nonzero, 513 * add the command to the table if it is not already present. The 514 * variable "lastcmdentry" is set to point to the address of the link 515 * pointing to the entry, so that delete_cmd_entry can delete the 516 * entry. 517 */ 518 519 static struct tblentry **lastcmdentry; 520 521 522 static struct tblentry * 523 cmdlookup(const char *name, int add) 524 { 525 int hashval; 526 const char *p; 527 struct tblentry *cmdp; 528 struct tblentry **pp; 529 size_t len; 530 531 p = name; 532 hashval = *p << 4; 533 while (*p) 534 hashval += *p++; 535 hashval &= 0x7FFF; 536 pp = &cmdtable[hashval % CMDTABLESIZE]; 537 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 538 if (equal(cmdp->cmdname, name)) 539 break; 540 pp = &cmdp->next; 541 } 542 if (add && cmdp == NULL) { 543 INTOFF; 544 len = strlen(name); 545 cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1); 546 cmdp->next = NULL; 547 cmdp->cmdtype = CMDUNKNOWN; 548 memcpy(cmdp->cmdname, name, len + 1); 549 INTON; 550 } 551 lastcmdentry = pp; 552 return cmdp; 553 } 554 555 /* 556 * Delete the command entry returned on the last lookup. 557 */ 558 559 static void 560 delete_cmd_entry(void) 561 { 562 struct tblentry *cmdp; 563 564 INTOFF; 565 cmdp = *lastcmdentry; 566 *lastcmdentry = cmdp->next; 567 ckfree(cmdp); 568 INTON; 569 } 570 571 572 573 /* 574 * Add a new command entry, replacing any existing command entry for 575 * the same name. 576 */ 577 578 static void 579 addcmdentry(const char *name, struct cmdentry *entry) 580 { 581 struct tblentry *cmdp; 582 583 INTOFF; 584 cmdp = cmdlookup(name, 1); 585 if (cmdp->cmdtype == CMDFUNCTION) { 586 unreffunc(cmdp->param.func); 587 } 588 cmdp->cmdtype = entry->cmdtype; 589 cmdp->param = entry->u; 590 INTON; 591 } 592 593 594 /* 595 * Define a shell function. 596 */ 597 598 void 599 defun(const char *name, union node *func) 600 { 601 struct cmdentry entry; 602 603 INTOFF; 604 entry.cmdtype = CMDFUNCTION; 605 entry.u.func = copyfunc(func); 606 addcmdentry(name, &entry); 607 INTON; 608 } 609 610 611 /* 612 * Delete a function if it exists. 613 * Called with interrupts off. 614 */ 615 616 int 617 unsetfunc(const char *name) 618 { 619 struct tblentry *cmdp; 620 621 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 622 unreffunc(cmdp->param.func); 623 delete_cmd_entry(); 624 return (0); 625 } 626 return (0); 627 } 628 629 630 /* 631 * Check if a function by a certain name exists. 632 */ 633 int 634 isfunc(const char *name) 635 { 636 struct tblentry *cmdp; 637 cmdp = cmdlookup(name, 0); 638 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION); 639 } 640 641 642 /* 643 * Shared code for the following builtin commands: 644 * type, command -v, command -V 645 */ 646 647 int 648 typecmd_impl(int argc, char **argv, int cmd, const char *path) 649 { 650 struct cmdentry entry; 651 struct tblentry *cmdp; 652 const char * const *pp; 653 struct alias *ap; 654 int i; 655 int error1 = 0; 656 657 if (path != pathval()) 658 clearcmdentry(); 659 660 for (i = 1; i < argc; i++) { 661 /* First look at the keywords */ 662 for (pp = parsekwd; *pp; pp++) 663 if (**pp == *argv[i] && equal(*pp, argv[i])) 664 break; 665 666 if (*pp) { 667 if (cmd == TYPECMD_SMALLV) 668 out1fmt("%s\n", argv[i]); 669 else 670 out1fmt("%s is a shell keyword\n", argv[i]); 671 continue; 672 } 673 674 /* Then look at the aliases */ 675 if ((ap = lookupalias(argv[i], 1)) != NULL) { 676 if (cmd == TYPECMD_SMALLV) { 677 out1fmt("alias %s=", argv[i]); 678 out1qstr(ap->val); 679 outcslow('\n', out1); 680 } else 681 out1fmt("%s is an alias for %s\n", argv[i], 682 ap->val); 683 continue; 684 } 685 686 /* Then check if it is a tracked alias */ 687 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) { 688 entry.cmdtype = cmdp->cmdtype; 689 entry.u = cmdp->param; 690 entry.special = cmdp->special; 691 } 692 else { 693 /* Finally use brute force */ 694 find_command(argv[i], &entry, 0, path); 695 } 696 697 switch (entry.cmdtype) { 698 case CMDNORMAL: { 699 if (strchr(argv[i], '/') == NULL) { 700 const char *path2 = path; 701 char *name; 702 int j = entry.u.index; 703 do { 704 name = padvance(&path2, argv[i]); 705 stunalloc(name); 706 } while (--j >= 0); 707 if (cmd == TYPECMD_SMALLV) 708 out1fmt("%s\n", name); 709 else 710 out1fmt("%s is%s %s\n", argv[i], 711 (cmdp && cmd == TYPECMD_TYPE) ? 712 " a tracked alias for" : "", 713 name); 714 } else { 715 if (eaccess(argv[i], X_OK) == 0) { 716 if (cmd == TYPECMD_SMALLV) 717 out1fmt("%s\n", argv[i]); 718 else 719 out1fmt("%s is %s\n", argv[i], 720 argv[i]); 721 } else { 722 if (cmd != TYPECMD_SMALLV) 723 outfmt(out2, "%s: %s\n", 724 argv[i], strerror(errno)); 725 error1 |= 127; 726 } 727 } 728 break; 729 } 730 case CMDFUNCTION: 731 if (cmd == TYPECMD_SMALLV) 732 out1fmt("%s\n", argv[i]); 733 else 734 out1fmt("%s is a shell function\n", argv[i]); 735 break; 736 737 case CMDBUILTIN: 738 if (cmd == TYPECMD_SMALLV) 739 out1fmt("%s\n", argv[i]); 740 else if (entry.special) 741 out1fmt("%s is a special shell builtin\n", 742 argv[i]); 743 else 744 out1fmt("%s is a shell builtin\n", argv[i]); 745 break; 746 747 default: 748 if (cmd != TYPECMD_SMALLV) 749 outfmt(out2, "%s: not found\n", argv[i]); 750 error1 |= 127; 751 break; 752 } 753 } 754 755 if (path != pathval()) 756 clearcmdentry(); 757 758 return error1; 759 } 760 761 /* 762 * Locate and print what a word is... 763 */ 764 765 int 766 typecmd(int argc, char **argv) 767 { 768 if (argc > 2 && strcmp(argv[1], "--") == 0) 769 argc--, argv++; 770 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1)); 771 } 772