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 #define ARB 1 /* actual size determined at run time */ 82 83 84 85 struct tblentry { 86 struct tblentry *next; /* next entry in hash chain */ 87 union param param; /* definition of builtin function */ 88 int special; /* flag for special builtin commands */ 89 short cmdtype; /* index identifying command */ 90 char rehash; /* if set, cd done since entry created */ 91 char cmdname[ARB]; /* name of command */ 92 }; 93 94 95 static struct tblentry *cmdtable[CMDTABLESIZE]; 96 int exerrno = 0; /* Last exec error */ 97 98 99 static void tryexec(char *, char **, char **); 100 static void printentry(struct tblentry *, int); 101 static struct tblentry *cmdlookup(const char *, int); 102 static void delete_cmd_entry(void); 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; 233 234 verbose = 0; 235 while ((c = nextopt("rv")) != '\0') { 236 if (c == 'r') { 237 clearcmdentry(); 238 } else if (c == 'v') { 239 verbose++; 240 } 241 } 242 if (*argptr == NULL) { 243 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 244 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 245 if (cmdp->cmdtype == CMDNORMAL) 246 printentry(cmdp, verbose); 247 } 248 } 249 return 0; 250 } 251 while ((name = *argptr) != NULL) { 252 if ((cmdp = cmdlookup(name, 0)) != NULL 253 && cmdp->cmdtype == CMDNORMAL) 254 delete_cmd_entry(); 255 find_command(name, &entry, DO_ERR, pathval()); 256 if (verbose) { 257 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */ 258 cmdp = cmdlookup(name, 0); 259 if (cmdp != NULL) 260 printentry(cmdp, verbose); 261 else 262 outfmt(out2, "%s: not found\n", name); 263 } 264 flushall(); 265 } 266 argptr++; 267 } 268 return 0; 269 } 270 271 272 static void 273 printentry(struct tblentry *cmdp, int verbose) 274 { 275 int idx; 276 const char *path; 277 char *name; 278 279 if (cmdp->cmdtype == CMDNORMAL) { 280 idx = cmdp->param.index; 281 path = pathval(); 282 do { 283 name = padvance(&path, cmdp->cmdname); 284 stunalloc(name); 285 } while (--idx >= 0); 286 out1str(name); 287 } else if (cmdp->cmdtype == CMDBUILTIN) { 288 out1fmt("builtin %s", cmdp->cmdname); 289 } else if (cmdp->cmdtype == CMDFUNCTION) { 290 out1fmt("function %s", cmdp->cmdname); 291 if (verbose) { 292 INTOFF; 293 name = commandtext(getfuncnode(cmdp->param.func)); 294 out1c(' '); 295 out1str(name); 296 ckfree(name); 297 INTON; 298 } 299 #ifdef DEBUG 300 } else { 301 error("internal error: cmdtype %d", cmdp->cmdtype); 302 #endif 303 } 304 if (cmdp->rehash) 305 out1c('*'); 306 out1c('\n'); 307 } 308 309 310 311 /* 312 * Resolve a command name. If you change this routine, you may have to 313 * change the shellexec routine as well. 314 */ 315 316 void 317 find_command(const char *name, struct cmdentry *entry, int act, 318 const char *path) 319 { 320 struct tblentry *cmdp, loc_cmd; 321 int idx; 322 int prev; 323 char *fullname; 324 struct stat statb; 325 int e; 326 int i; 327 int spec; 328 329 /* If name contains a slash, don't use the hash table */ 330 if (strchr(name, '/') != NULL) { 331 entry->cmdtype = CMDNORMAL; 332 entry->u.index = 0; 333 return; 334 } 335 336 /* If name is in the table, and not invalidated by cd, we're done */ 337 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) { 338 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC) 339 cmdp = NULL; 340 else 341 goto success; 342 } 343 344 /* Check for builtin next */ 345 if ((i = find_builtin(name, &spec)) >= 0) { 346 INTOFF; 347 cmdp = cmdlookup(name, 1); 348 if (cmdp->cmdtype == CMDFUNCTION) 349 cmdp = &loc_cmd; 350 cmdp->cmdtype = CMDBUILTIN; 351 cmdp->param.index = i; 352 cmdp->special = spec; 353 INTON; 354 goto success; 355 } 356 357 /* We have to search path. */ 358 prev = -1; /* where to start */ 359 if (cmdp) { /* doing a rehash */ 360 if (cmdp->cmdtype == CMDBUILTIN) 361 prev = -1; 362 else 363 prev = cmdp->param.index; 364 } 365 366 e = ENOENT; 367 idx = -1; 368 loop: 369 while ((fullname = padvance(&path, name)) != NULL) { 370 stunalloc(fullname); 371 idx++; 372 if (pathopt) { 373 if (prefix("func", pathopt)) { 374 /* handled below */ 375 } else { 376 goto loop; /* ignore unimplemented options */ 377 } 378 } 379 /* if rehash, don't redo absolute path names */ 380 if (fullname[0] == '/' && idx <= prev) { 381 if (idx < prev) 382 goto loop; 383 TRACE(("searchexec \"%s\": no change\n", name)); 384 goto success; 385 } 386 if (stat(fullname, &statb) < 0) { 387 if (errno != ENOENT && errno != ENOTDIR) 388 e = errno; 389 goto loop; 390 } 391 e = EACCES; /* if we fail, this will be the error */ 392 if (!S_ISREG(statb.st_mode)) 393 goto loop; 394 if (pathopt) { /* this is a %func directory */ 395 stalloc(strlen(fullname) + 1); 396 readcmdfile(fullname); 397 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 398 error("%s not defined in %s", name, fullname); 399 stunalloc(fullname); 400 goto success; 401 } 402 #ifdef notdef 403 if (statb.st_uid == geteuid()) { 404 if ((statb.st_mode & 0100) == 0) 405 goto loop; 406 } else if (statb.st_gid == getegid()) { 407 if ((statb.st_mode & 010) == 0) 408 goto loop; 409 } else { 410 if ((statb.st_mode & 01) == 0) 411 goto loop; 412 } 413 #endif 414 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 415 INTOFF; 416 cmdp = cmdlookup(name, 1); 417 if (cmdp->cmdtype == CMDFUNCTION) 418 cmdp = &loc_cmd; 419 cmdp->cmdtype = CMDNORMAL; 420 cmdp->param.index = idx; 421 INTON; 422 goto success; 423 } 424 425 /* We failed. If there was an entry for this command, delete it */ 426 if (cmdp && cmdp->cmdtype != CMDFUNCTION) 427 delete_cmd_entry(); 428 if (act & DO_ERR) { 429 if (e == ENOENT || e == ENOTDIR) 430 outfmt(out2, "%s: not found\n", name); 431 else 432 outfmt(out2, "%s: %s\n", name, strerror(e)); 433 } 434 entry->cmdtype = CMDUNKNOWN; 435 entry->u.index = 0; 436 return; 437 438 success: 439 cmdp->rehash = 0; 440 entry->cmdtype = cmdp->cmdtype; 441 entry->u = cmdp->param; 442 entry->special = cmdp->special; 443 } 444 445 446 447 /* 448 * Search the table of builtin commands. 449 */ 450 451 int 452 find_builtin(const char *name, int *special) 453 { 454 const struct builtincmd *bp; 455 456 for (bp = builtincmd ; bp->name ; bp++) { 457 if (*bp->name == *name && equal(bp->name, name)) { 458 *special = bp->special; 459 return bp->code; 460 } 461 } 462 return -1; 463 } 464 465 466 467 /* 468 * Called when a cd is done. Marks all commands so the next time they 469 * are executed they will be rehashed. 470 */ 471 472 void 473 hashcd(void) 474 { 475 struct tblentry **pp; 476 struct tblentry *cmdp; 477 478 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 479 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 480 if (cmdp->cmdtype == CMDNORMAL) 481 cmdp->rehash = 1; 482 } 483 } 484 } 485 486 487 488 /* 489 * Called before PATH is changed. The argument is the new value of PATH; 490 * pathval() still returns the old value at this point. Called with 491 * interrupts off. 492 */ 493 494 void 495 changepath(const char *newval) 496 { 497 clearcmdentry(); 498 } 499 500 501 /* 502 * Clear out command entries. The argument specifies the first entry in 503 * PATH which has changed. 504 */ 505 506 void 507 clearcmdentry(void) 508 { 509 struct tblentry **tblp; 510 struct tblentry **pp; 511 struct tblentry *cmdp; 512 513 INTOFF; 514 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 515 pp = tblp; 516 while ((cmdp = *pp) != NULL) { 517 if (cmdp->cmdtype == CMDNORMAL) { 518 *pp = cmdp->next; 519 ckfree(cmdp); 520 } else { 521 pp = &cmdp->next; 522 } 523 } 524 } 525 INTON; 526 } 527 528 529 /* 530 * Locate a command in the command hash table. If "add" is nonzero, 531 * add the command to the table if it is not already present. The 532 * variable "lastcmdentry" is set to point to the address of the link 533 * pointing to the entry, so that delete_cmd_entry can delete the 534 * entry. 535 */ 536 537 static struct tblentry **lastcmdentry; 538 539 540 static struct tblentry * 541 cmdlookup(const char *name, int add) 542 { 543 int hashval; 544 const char *p; 545 struct tblentry *cmdp; 546 struct tblentry **pp; 547 548 p = name; 549 hashval = *p << 4; 550 while (*p) 551 hashval += *p++; 552 hashval &= 0x7FFF; 553 pp = &cmdtable[hashval % CMDTABLESIZE]; 554 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 555 if (equal(cmdp->cmdname, name)) 556 break; 557 pp = &cmdp->next; 558 } 559 if (add && cmdp == NULL) { 560 INTOFF; 561 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB 562 + strlen(name) + 1); 563 cmdp->next = NULL; 564 cmdp->cmdtype = CMDUNKNOWN; 565 cmdp->rehash = 0; 566 strcpy(cmdp->cmdname, name); 567 INTON; 568 } 569 lastcmdentry = pp; 570 return cmdp; 571 } 572 573 /* 574 * Delete the command entry returned on the last lookup. 575 */ 576 577 static void 578 delete_cmd_entry(void) 579 { 580 struct tblentry *cmdp; 581 582 INTOFF; 583 cmdp = *lastcmdentry; 584 *lastcmdentry = cmdp->next; 585 ckfree(cmdp); 586 INTON; 587 } 588 589 590 591 /* 592 * Add a new command entry, replacing any existing command entry for 593 * the same name. 594 */ 595 596 void 597 addcmdentry(const char *name, struct cmdentry *entry) 598 { 599 struct tblentry *cmdp; 600 601 INTOFF; 602 cmdp = cmdlookup(name, 1); 603 if (cmdp->cmdtype == CMDFUNCTION) { 604 unreffunc(cmdp->param.func); 605 } 606 cmdp->cmdtype = entry->cmdtype; 607 cmdp->param = entry->u; 608 INTON; 609 } 610 611 612 /* 613 * Define a shell function. 614 */ 615 616 void 617 defun(const char *name, union node *func) 618 { 619 struct cmdentry entry; 620 621 INTOFF; 622 entry.cmdtype = CMDFUNCTION; 623 entry.u.func = copyfunc(func); 624 addcmdentry(name, &entry); 625 INTON; 626 } 627 628 629 /* 630 * Delete a function if it exists. 631 */ 632 633 int 634 unsetfunc(const char *name) 635 { 636 struct tblentry *cmdp; 637 638 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 639 unreffunc(cmdp->param.func); 640 delete_cmd_entry(); 641 return (0); 642 } 643 return (0); 644 } 645 646 /* 647 * Shared code for the following builtin commands: 648 * type, command -v, command -V 649 */ 650 651 int 652 typecmd_impl(int argc, char **argv, int cmd, const char *path) 653 { 654 struct cmdentry entry; 655 struct tblentry *cmdp; 656 const char *const *pp; 657 struct alias *ap; 658 int i; 659 int error1 = 0; 660 661 if (path != pathval()) 662 clearcmdentry(); 663 664 for (i = 1; i < argc; i++) { 665 /* First look at the keywords */ 666 for (pp = parsekwd; *pp; pp++) 667 if (**pp == *argv[i] && equal(*pp, argv[i])) 668 break; 669 670 if (*pp) { 671 if (cmd == TYPECMD_SMALLV) 672 out1fmt("%s\n", argv[i]); 673 else 674 out1fmt("%s is a shell keyword\n", argv[i]); 675 continue; 676 } 677 678 /* Then look at the aliases */ 679 if ((ap = lookupalias(argv[i], 1)) != NULL) { 680 if (cmd == TYPECMD_SMALLV) 681 out1fmt("alias %s='%s'\n", argv[i], ap->val); 682 else 683 out1fmt("%s is an alias for %s\n", argv[i], 684 ap->val); 685 continue; 686 } 687 688 /* Then check if it is a tracked alias */ 689 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) { 690 entry.cmdtype = cmdp->cmdtype; 691 entry.u = cmdp->param; 692 entry.special = cmdp->special; 693 } 694 else { 695 /* Finally use brute force */ 696 find_command(argv[i], &entry, 0, path); 697 } 698 699 switch (entry.cmdtype) { 700 case CMDNORMAL: { 701 if (strchr(argv[i], '/') == NULL) { 702 const char *path2 = path; 703 char *name; 704 int j = entry.u.index; 705 do { 706 name = padvance(&path2, argv[i]); 707 stunalloc(name); 708 } while (--j >= 0); 709 if (cmd == TYPECMD_SMALLV) 710 out1fmt("%s\n", name); 711 else 712 out1fmt("%s is%s %s\n", argv[i], 713 (cmdp && cmd == TYPECMD_TYPE) ? 714 " a tracked alias for" : "", 715 name); 716 } else { 717 if (eaccess(argv[i], X_OK) == 0) { 718 if (cmd == TYPECMD_SMALLV) 719 out1fmt("%s\n", argv[i]); 720 else 721 out1fmt("%s is %s\n", argv[i], 722 argv[i]); 723 } else { 724 if (cmd != TYPECMD_SMALLV) 725 outfmt(out2, "%s: %s\n", 726 argv[i], strerror(errno)); 727 error1 |= 127; 728 } 729 } 730 break; 731 } 732 case CMDFUNCTION: 733 if (cmd == TYPECMD_SMALLV) 734 out1fmt("%s\n", argv[i]); 735 else 736 out1fmt("%s is a shell function\n", argv[i]); 737 break; 738 739 case CMDBUILTIN: 740 if (cmd == TYPECMD_SMALLV) 741 out1fmt("%s\n", argv[i]); 742 else if (entry.special) 743 out1fmt("%s is a special shell builtin\n", 744 argv[i]); 745 else 746 out1fmt("%s is a shell builtin\n", argv[i]); 747 break; 748 749 default: 750 if (cmd != TYPECMD_SMALLV) 751 outfmt(out2, "%s: not found\n", argv[i]); 752 error1 |= 127; 753 break; 754 } 755 } 756 757 if (path != pathval()) 758 clearcmdentry(); 759 760 return error1; 761 } 762 763 /* 764 * Locate and print what a word is... 765 */ 766 767 int 768 typecmd(int argc, char **argv) 769 { 770 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1)); 771 } 772