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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * $Id$ 37 */ 38 39 #ifndef lint 40 static char const sccsid[] = "@(#)exec.c 8.4 (Berkeley) 6/8/95"; 41 #endif /* not lint */ 42 43 #include <sys/types.h> 44 #include <sys/stat.h> 45 #include <unistd.h> 46 #include <fcntl.h> 47 #include <errno.h> 48 #include <stdlib.h> 49 50 /* 51 * When commands are first encountered, they are entered in a hash table. 52 * This ensures that a full path search will not have to be done for them 53 * on each invocation. 54 * 55 * We should investigate converting to a linear search, even though that 56 * would make the command name "hash" a misnomer. 57 */ 58 59 #include "shell.h" 60 #include "main.h" 61 #include "nodes.h" 62 #include "parser.h" 63 #include "redir.h" 64 #include "eval.h" 65 #include "exec.h" 66 #include "builtins.h" 67 #include "var.h" 68 #include "options.h" 69 #include "input.h" 70 #include "output.h" 71 #include "syntax.h" 72 #include "memalloc.h" 73 #include "error.h" 74 #include "init.h" 75 #include "mystring.h" 76 #include "show.h" 77 #include "jobs.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 short cmdtype; /* index identifying command */ 89 char rehash; /* if set, cd done since entry created */ 90 char cmdname[ARB]; /* name of command */ 91 }; 92 93 94 STATIC struct tblentry *cmdtable[CMDTABLESIZE]; 95 STATIC int builtinloc = -1; /* index in path of %builtin, or -1 */ 96 int exerrno = 0; /* Last exec error */ 97 98 99 STATIC void tryexec __P((char *, char **, char **)); 100 #ifndef BSD 101 STATIC void execinterp __P((char **, char **)); 102 #endif 103 STATIC void printentry __P((struct tblentry *, int)); 104 STATIC void clearcmdentry __P((int)); 105 STATIC struct tblentry *cmdlookup __P((char *, int)); 106 STATIC void delete_cmd_entry __P((void)); 107 108 109 110 /* 111 * Exec a program. Never returns. If you change this routine, you may 112 * have to change the find_command routine as well. 113 */ 114 115 void 116 shellexec(argv, envp, path, index) 117 char **argv, **envp; 118 char *path; 119 int index; 120 { 121 char *cmdname; 122 int e; 123 124 if (strchr(argv[0], '/') != NULL) { 125 tryexec(argv[0], argv, envp); 126 e = errno; 127 } else { 128 e = ENOENT; 129 while ((cmdname = padvance(&path, argv[0])) != NULL) { 130 if (--index < 0 && pathopt == NULL) { 131 tryexec(cmdname, argv, envp); 132 if (errno != ENOENT && errno != ENOTDIR) 133 e = errno; 134 } 135 stunalloc(cmdname); 136 } 137 } 138 139 /* Map to POSIX errors */ 140 switch (e) { 141 case EACCES: 142 exerrno = 126; 143 break; 144 case ENOENT: 145 exerrno = 127; 146 break; 147 default: 148 exerrno = 2; 149 break; 150 } 151 exerror(EXEXEC, "%s: %s", argv[0], errmsg(e, E_EXEC)); 152 } 153 154 155 STATIC void 156 tryexec(cmd, argv, envp) 157 char *cmd; 158 char **argv; 159 char **envp; 160 { 161 int e; 162 #ifndef BSD 163 char *p; 164 #endif 165 166 #ifdef SYSV 167 do { 168 execve(cmd, argv, envp); 169 } while (errno == EINTR); 170 #else 171 execve(cmd, argv, envp); 172 #endif 173 e = errno; 174 if (e == ENOEXEC) { 175 initshellproc(); 176 setinputfile(cmd, 0); 177 commandname = arg0 = savestr(argv[0]); 178 #ifndef BSD 179 pgetc(); pungetc(); /* fill up input buffer */ 180 p = parsenextc; 181 if (parsenleft > 2 && p[0] == '#' && p[1] == '!') { 182 argv[0] = cmd; 183 execinterp(argv, envp); 184 } 185 #endif 186 setparam(argv + 1); 187 exraise(EXSHELLPROC); 188 /*NOTREACHED*/ 189 } 190 errno = e; 191 } 192 193 194 #ifndef BSD 195 /* 196 * Execute an interpreter introduced by "#!", for systems where this 197 * feature has not been built into the kernel. If the interpreter is 198 * the shell, return (effectively ignoring the "#!"). If the execution 199 * of the interpreter fails, exit. 200 * 201 * This code peeks inside the input buffer in order to avoid actually 202 * reading any input. It would benefit from a rewrite. 203 */ 204 205 #define NEWARGS 5 206 207 STATIC void 208 execinterp(argv, envp) 209 char **argv, **envp; 210 { 211 int n; 212 char *inp; 213 char *outp; 214 char c; 215 char *p; 216 char **ap; 217 char *newargs[NEWARGS]; 218 int i; 219 char **ap2; 220 char **new; 221 222 n = parsenleft - 2; 223 inp = parsenextc + 2; 224 ap = newargs; 225 for (;;) { 226 while (--n >= 0 && (*inp == ' ' || *inp == '\t')) 227 inp++; 228 if (n < 0) 229 goto bad; 230 if ((c = *inp++) == '\n') 231 break; 232 if (ap == &newargs[NEWARGS]) 233 bad: error("Bad #! line"); 234 STARTSTACKSTR(outp); 235 do { 236 STPUTC(c, outp); 237 } while (--n >= 0 && (c = *inp++) != ' ' && c != '\t' && c != '\n'); 238 STPUTC('\0', outp); 239 n++, inp--; 240 *ap++ = grabstackstr(outp); 241 } 242 if (ap == newargs + 1) { /* if no args, maybe no exec is needed */ 243 p = newargs[0]; 244 for (;;) { 245 if (equal(p, "sh") || equal(p, "ash")) { 246 return; 247 } 248 while (*p != '/') { 249 if (*p == '\0') 250 goto break2; 251 p++; 252 } 253 p++; 254 } 255 break2:; 256 } 257 i = (char *)ap - (char *)newargs; /* size in bytes */ 258 if (i == 0) 259 error("Bad #! line"); 260 for (ap2 = argv ; *ap2++ != NULL ; ); 261 new = ckmalloc(i + ((char *)ap2 - (char *)argv)); 262 ap = newargs, ap2 = new; 263 while ((i -= sizeof (char **)) >= 0) 264 *ap2++ = *ap++; 265 ap = argv; 266 while (*ap2++ = *ap++); 267 shellexec(new, envp, pathval(), 0); 268 } 269 #endif 270 271 272 273 /* 274 * Do a path search. The variable path (passed by reference) should be 275 * set to the start of the path before the first call; padvance will update 276 * this value as it proceeds. Successive calls to padvance will return 277 * the possible path expansions in sequence. If an option (indicated by 278 * a percent sign) appears in the path entry then the global variable 279 * pathopt will be set to point to it; otherwise pathopt will be set to 280 * NULL. 281 */ 282 283 char *pathopt; 284 285 char * 286 padvance(path, name) 287 char **path; 288 char *name; 289 { 290 register char *p, *q; 291 char *start; 292 int len; 293 294 if (*path == NULL) 295 return NULL; 296 start = *path; 297 for (p = start ; *p && *p != ':' && *p != '%' ; p++); 298 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */ 299 while (stackblocksize() < len) 300 growstackblock(); 301 q = stackblock(); 302 if (p != start) { 303 memcpy(q, start, p - start); 304 q += p - start; 305 *q++ = '/'; 306 } 307 strcpy(q, name); 308 pathopt = NULL; 309 if (*p == '%') { 310 pathopt = ++p; 311 while (*p && *p != ':') p++; 312 } 313 if (*p == ':') 314 *path = p + 1; 315 else 316 *path = NULL; 317 return stalloc(len); 318 } 319 320 321 322 /*** Command hashing code ***/ 323 324 325 int 326 hashcmd(argc, argv) 327 int argc; 328 char **argv; 329 { 330 struct tblentry **pp; 331 struct tblentry *cmdp; 332 int c; 333 int verbose; 334 struct cmdentry entry; 335 char *name; 336 337 verbose = 0; 338 while ((c = nextopt("rv")) != '\0') { 339 if (c == 'r') { 340 clearcmdentry(0); 341 } else if (c == 'v') { 342 verbose++; 343 } 344 } 345 if (*argptr == NULL) { 346 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 347 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 348 printentry(cmdp, verbose); 349 } 350 } 351 return 0; 352 } 353 while ((name = *argptr) != NULL) { 354 if ((cmdp = cmdlookup(name, 0)) != NULL 355 && (cmdp->cmdtype == CMDNORMAL 356 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))) 357 delete_cmd_entry(); 358 find_command(name, &entry, 1, pathval()); 359 if (verbose) { 360 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */ 361 cmdp = cmdlookup(name, 0); 362 printentry(cmdp, verbose); 363 } 364 flushall(); 365 } 366 argptr++; 367 } 368 return 0; 369 } 370 371 372 STATIC void 373 printentry(cmdp, verbose) 374 struct tblentry *cmdp; 375 int verbose; 376 { 377 int index; 378 char *path; 379 char *name; 380 381 if (cmdp->cmdtype == CMDNORMAL) { 382 index = cmdp->param.index; 383 path = pathval(); 384 do { 385 name = padvance(&path, cmdp->cmdname); 386 stunalloc(name); 387 } while (--index >= 0); 388 out1str(name); 389 } else if (cmdp->cmdtype == CMDBUILTIN) { 390 out1fmt("builtin %s", cmdp->cmdname); 391 } else if (cmdp->cmdtype == CMDFUNCTION) { 392 out1fmt("function %s", cmdp->cmdname); 393 if (verbose) { 394 INTOFF; 395 name = commandtext(cmdp->param.func); 396 out1c(' '); 397 out1str(name); 398 ckfree(name); 399 INTON; 400 } 401 #ifdef DEBUG 402 } else { 403 error("internal error: cmdtype %d", cmdp->cmdtype); 404 #endif 405 } 406 if (cmdp->rehash) 407 out1c('*'); 408 out1c('\n'); 409 } 410 411 412 413 /* 414 * Resolve a command name. If you change this routine, you may have to 415 * change the shellexec routine as well. 416 */ 417 418 void 419 find_command(name, entry, printerr, path) 420 char *name; 421 struct cmdentry *entry; 422 int printerr; 423 char *path; 424 { 425 struct tblentry *cmdp; 426 int index; 427 int prev; 428 char *fullname; 429 struct stat statb; 430 int e; 431 int i; 432 433 /* If name contains a slash, don't use the hash table */ 434 if (strchr(name, '/') != NULL) { 435 entry->cmdtype = CMDNORMAL; 436 entry->u.index = 0; 437 return; 438 } 439 440 /* If name is in the table, and not invalidated by cd, we're done */ 441 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) 442 goto success; 443 444 /* If %builtin not in path, check for builtin next */ 445 if (builtinloc < 0 && (i = find_builtin(name)) >= 0) { 446 INTOFF; 447 cmdp = cmdlookup(name, 1); 448 cmdp->cmdtype = CMDBUILTIN; 449 cmdp->param.index = i; 450 INTON; 451 goto success; 452 } 453 454 /* We have to search path. */ 455 prev = -1; /* where to start */ 456 if (cmdp) { /* doing a rehash */ 457 if (cmdp->cmdtype == CMDBUILTIN) 458 prev = builtinloc; 459 else 460 prev = cmdp->param.index; 461 } 462 463 e = ENOENT; 464 index = -1; 465 loop: 466 while ((fullname = padvance(&path, name)) != NULL) { 467 stunalloc(fullname); 468 index++; 469 if (pathopt) { 470 if (prefix("builtin", pathopt)) { 471 if ((i = find_builtin(name)) < 0) 472 goto loop; 473 INTOFF; 474 cmdp = cmdlookup(name, 1); 475 cmdp->cmdtype = CMDBUILTIN; 476 cmdp->param.index = i; 477 INTON; 478 goto success; 479 } else if (prefix("func", pathopt)) { 480 /* handled below */ 481 } else { 482 goto loop; /* ignore unimplemented options */ 483 } 484 } 485 /* if rehash, don't redo absolute path names */ 486 if (fullname[0] == '/' && index <= prev) { 487 if (index < prev) 488 goto loop; 489 TRACE(("searchexec \"%s\": no change\n", name)); 490 goto success; 491 } 492 while (stat(fullname, &statb) < 0) { 493 #ifdef SYSV 494 if (errno == EINTR) 495 continue; 496 #endif 497 if (errno != ENOENT && errno != ENOTDIR) 498 e = errno; 499 goto loop; 500 } 501 e = EACCES; /* if we fail, this will be the error */ 502 if (!S_ISREG(statb.st_mode)) 503 goto loop; 504 if (pathopt) { /* this is a %func directory */ 505 stalloc(strlen(fullname) + 1); 506 readcmdfile(fullname); 507 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 508 error("%s not defined in %s", name, fullname); 509 stunalloc(fullname); 510 goto success; 511 } 512 #ifdef notdef 513 if (statb.st_uid == geteuid()) { 514 if ((statb.st_mode & 0100) == 0) 515 goto loop; 516 } else if (statb.st_gid == getegid()) { 517 if ((statb.st_mode & 010) == 0) 518 goto loop; 519 } else { 520 if ((statb.st_mode & 01) == 0) 521 goto loop; 522 } 523 #endif 524 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 525 INTOFF; 526 cmdp = cmdlookup(name, 1); 527 cmdp->cmdtype = CMDNORMAL; 528 cmdp->param.index = index; 529 INTON; 530 goto success; 531 } 532 533 /* We failed. If there was an entry for this command, delete it */ 534 if (cmdp) 535 delete_cmd_entry(); 536 if (printerr) 537 outfmt(out2, "%s: %s\n", name, errmsg(e, E_EXEC)); 538 entry->cmdtype = CMDUNKNOWN; 539 return; 540 541 success: 542 cmdp->rehash = 0; 543 entry->cmdtype = cmdp->cmdtype; 544 entry->u = cmdp->param; 545 } 546 547 548 549 /* 550 * Search the table of builtin commands. 551 */ 552 553 int 554 find_builtin(name) 555 char *name; 556 { 557 register const struct builtincmd *bp; 558 559 for (bp = builtincmd ; bp->name ; bp++) { 560 if (*bp->name == *name && equal(bp->name, name)) 561 return bp->code; 562 } 563 return -1; 564 } 565 566 567 568 /* 569 * Called when a cd is done. Marks all commands so the next time they 570 * are executed they will be rehashed. 571 */ 572 573 void 574 hashcd() { 575 struct tblentry **pp; 576 struct tblentry *cmdp; 577 578 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 579 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 580 if (cmdp->cmdtype == CMDNORMAL 581 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)) 582 cmdp->rehash = 1; 583 } 584 } 585 } 586 587 588 589 /* 590 * Called before PATH is changed. The argument is the new value of PATH; 591 * pathval() still returns the old value at this point. Called with 592 * interrupts off. 593 */ 594 595 void 596 changepath(newval) 597 const char *newval; 598 { 599 const char *old, *new; 600 int index; 601 int firstchange; 602 int bltin; 603 604 old = pathval(); 605 new = newval; 606 firstchange = 9999; /* assume no change */ 607 index = 0; 608 bltin = -1; 609 for (;;) { 610 if (*old != *new) { 611 firstchange = index; 612 if ((*old == '\0' && *new == ':') 613 || (*old == ':' && *new == '\0')) 614 firstchange++; 615 old = new; /* ignore subsequent differences */ 616 } 617 if (*new == '\0') 618 break; 619 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1)) 620 bltin = index; 621 if (*new == ':') { 622 index++; 623 } 624 new++, old++; 625 } 626 if (builtinloc < 0 && bltin >= 0) 627 builtinloc = bltin; /* zap builtins */ 628 if (builtinloc >= 0 && bltin < 0) 629 firstchange = 0; 630 clearcmdentry(firstchange); 631 builtinloc = bltin; 632 } 633 634 635 /* 636 * Clear out command entries. The argument specifies the first entry in 637 * PATH which has changed. 638 */ 639 640 STATIC void 641 clearcmdentry(firstchange) 642 int firstchange; 643 { 644 struct tblentry **tblp; 645 struct tblentry **pp; 646 struct tblentry *cmdp; 647 648 INTOFF; 649 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 650 pp = tblp; 651 while ((cmdp = *pp) != NULL) { 652 if ((cmdp->cmdtype == CMDNORMAL && 653 cmdp->param.index >= firstchange) 654 || (cmdp->cmdtype == CMDBUILTIN && 655 builtinloc >= firstchange)) { 656 *pp = cmdp->next; 657 ckfree(cmdp); 658 } else { 659 pp = &cmdp->next; 660 } 661 } 662 } 663 INTON; 664 } 665 666 667 /* 668 * Delete all functions. 669 */ 670 671 #ifdef mkinit 672 MKINIT void deletefuncs(); 673 674 SHELLPROC { 675 deletefuncs(); 676 } 677 #endif 678 679 void 680 deletefuncs() { 681 struct tblentry **tblp; 682 struct tblentry **pp; 683 struct tblentry *cmdp; 684 685 INTOFF; 686 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 687 pp = tblp; 688 while ((cmdp = *pp) != NULL) { 689 if (cmdp->cmdtype == CMDFUNCTION) { 690 *pp = cmdp->next; 691 freefunc(cmdp->param.func); 692 ckfree(cmdp); 693 } else { 694 pp = &cmdp->next; 695 } 696 } 697 } 698 INTON; 699 } 700 701 702 703 /* 704 * Locate a command in the command hash table. If "add" is nonzero, 705 * add the command to the table if it is not already present. The 706 * variable "lastcmdentry" is set to point to the address of the link 707 * pointing to the entry, so that delete_cmd_entry can delete the 708 * entry. 709 */ 710 711 struct tblentry **lastcmdentry; 712 713 714 STATIC struct tblentry * 715 cmdlookup(name, add) 716 char *name; 717 int add; 718 { 719 int hashval; 720 register char *p; 721 struct tblentry *cmdp; 722 struct tblentry **pp; 723 724 p = name; 725 hashval = *p << 4; 726 while (*p) 727 hashval += *p++; 728 hashval &= 0x7FFF; 729 pp = &cmdtable[hashval % CMDTABLESIZE]; 730 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 731 if (equal(cmdp->cmdname, name)) 732 break; 733 pp = &cmdp->next; 734 } 735 if (add && cmdp == NULL) { 736 INTOFF; 737 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB 738 + strlen(name) + 1); 739 cmdp->next = NULL; 740 cmdp->cmdtype = CMDUNKNOWN; 741 cmdp->rehash = 0; 742 strcpy(cmdp->cmdname, name); 743 INTON; 744 } 745 lastcmdentry = pp; 746 return cmdp; 747 } 748 749 /* 750 * Delete the command entry returned on the last lookup. 751 */ 752 753 STATIC void 754 delete_cmd_entry() { 755 struct tblentry *cmdp; 756 757 INTOFF; 758 cmdp = *lastcmdentry; 759 *lastcmdentry = cmdp->next; 760 ckfree(cmdp); 761 INTON; 762 } 763 764 765 766 #ifdef notdef 767 void 768 getcmdentry(name, entry) 769 char *name; 770 struct cmdentry *entry; 771 { 772 struct tblentry *cmdp = cmdlookup(name, 0); 773 774 if (cmdp) { 775 entry->u = cmdp->param; 776 entry->cmdtype = cmdp->cmdtype; 777 } else { 778 entry->cmdtype = CMDUNKNOWN; 779 entry->u.index = 0; 780 } 781 } 782 #endif 783 784 785 /* 786 * Add a new command entry, replacing any existing command entry for 787 * the same name. 788 */ 789 790 void 791 addcmdentry(name, entry) 792 char *name; 793 struct cmdentry *entry; 794 { 795 struct tblentry *cmdp; 796 797 INTOFF; 798 cmdp = cmdlookup(name, 1); 799 if (cmdp->cmdtype == CMDFUNCTION) { 800 freefunc(cmdp->param.func); 801 } 802 cmdp->cmdtype = entry->cmdtype; 803 cmdp->param = entry->u; 804 INTON; 805 } 806 807 808 /* 809 * Define a shell function. 810 */ 811 812 void 813 defun(name, func) 814 char *name; 815 union node *func; 816 { 817 struct cmdentry entry; 818 819 INTOFF; 820 entry.cmdtype = CMDFUNCTION; 821 entry.u.func = copyfunc(func); 822 addcmdentry(name, &entry); 823 INTON; 824 } 825 826 827 /* 828 * Delete a function if it exists. 829 */ 830 831 int 832 unsetfunc(name) 833 char *name; 834 { 835 struct tblentry *cmdp; 836 837 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 838 freefunc(cmdp->param.func); 839 delete_cmd_entry(); 840 return (0); 841 } 842 return (1); 843 } 844