1 /*- 2 * Copyright (c) 1991 The Regents of the University of California. 3 * 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 37 #ifndef lint 38 static char sccsid[] = "@(#)exec.c 5.2 (Berkeley) 3/13/91"; 39 static char rcsid[] = "$Header: /cvsroot/src/bin/sh/exec.c,v 1.4 1993/04/10 14:55:52 cgd Exp $"; 40 #endif /* not lint */ 41 42 /* 43 * When commands are first encountered, they are entered in a hash table. 44 * This ensures that a full path search will not have to be done for them 45 * on each invocation. 46 * 47 * We should investigate converting to a linear search, even though that 48 * would make the command name "hash" a misnomer. 49 */ 50 51 #include "shell.h" 52 #include "main.h" 53 #include "nodes.h" 54 #include "parser.h" 55 #include "redir.h" 56 #include "eval.h" 57 #include "exec.h" 58 #include "builtins.h" 59 #include "var.h" 60 #include "options.h" 61 #include "input.h" 62 #include "output.h" 63 #include "syntax.h" 64 #include "memalloc.h" 65 #include "error.h" 66 #include "init.h" 67 #include "mystring.h" 68 #include <sys/types.h> 69 #include <sys/stat.h> 70 #include <fcntl.h> 71 #include <errno.h> 72 #ifdef BSD 73 #undef BSD /* temporary, already defined in <sys/param.h> */ 74 #include <sys/param.h> 75 #include <unistd.h> 76 #endif 77 78 79 #define CMDTABLESIZE 31 /* should be prime */ 80 #define ARB 1 /* actual size determined at run time */ 81 82 83 84 struct tblentry { 85 struct tblentry *next; /* next entry in hash chain */ 86 union param param; /* definition of builtin function */ 87 short cmdtype; /* index identifying command */ 88 char rehash; /* if set, cd done since entry created */ 89 char cmdname[ARB]; /* name of command */ 90 }; 91 92 93 STATIC struct tblentry *cmdtable[CMDTABLESIZE]; 94 STATIC int builtinloc = -1; /* index in path of %builtin, or -1 */ 95 96 97 #ifdef __STDC__ 98 STATIC void tryexec(char *, char **, char **); 99 STATIC void execinterp(char **, char **); 100 STATIC void printentry(struct tblentry *); 101 STATIC void clearcmdentry(int); 102 STATIC struct tblentry *cmdlookup(char *, int); 103 STATIC void delete_cmd_entry(void); 104 #else 105 STATIC void tryexec(); 106 STATIC void execinterp(); 107 STATIC void printentry(); 108 STATIC void clearcmdentry(); 109 STATIC struct tblentry *cmdlookup(); 110 STATIC void delete_cmd_entry(); 111 #endif 112 113 114 115 /* 116 * Exec a program. Never returns. If you change this routine, you may 117 * have to change the find_command routine as well. 118 */ 119 120 void 121 shellexec(argv, envp, path, index) 122 char **argv, **envp; 123 char *path; 124 { 125 char *cmdname; 126 int e; 127 128 if (strchr(argv[0], '/') != NULL) { 129 tryexec(argv[0], argv, envp); 130 e = errno; 131 } else { 132 e = ENOENT; 133 while ((cmdname = padvance(&path, argv[0])) != NULL) { 134 if (--index < 0 && pathopt == NULL) { 135 tryexec(cmdname, argv, envp); 136 if (errno != ENOENT && errno != ENOTDIR) 137 e = errno; 138 } 139 stunalloc(cmdname); 140 } 141 } 142 error2(argv[0], errmsg(e, E_EXEC)); 143 } 144 145 146 STATIC void 147 tryexec(cmd, argv, envp) 148 char *cmd; 149 char **argv; 150 char **envp; 151 { 152 int e; 153 char *p; 154 155 #ifdef SYSV 156 do { 157 execve(cmd, argv, envp); 158 } while (errno == EINTR); 159 #else 160 execve(cmd, argv, envp); 161 #endif 162 e = errno; 163 if (e == ENOEXEC) { 164 initshellproc(); 165 setinputfile(cmd, 0); 166 commandname = arg0 = savestr(argv[0]); 167 #ifndef BSD 168 pgetc(); pungetc(); /* fill up input buffer */ 169 p = parsenextc; 170 if (parsenleft > 2 && p[0] == '#' && p[1] == '!') { 171 argv[0] = cmd; 172 execinterp(argv, envp); 173 } 174 #endif 175 setparam(argv + 1); 176 exraise(EXSHELLPROC); 177 /*NOTREACHED*/ 178 } 179 errno = e; 180 } 181 182 183 #ifndef BSD 184 /* 185 * Execute an interpreter introduced by "#!", for systems where this 186 * feature has not been built into the kernel. If the interpreter is 187 * the shell, return (effectively ignoring the "#!"). If the execution 188 * of the interpreter fails, exit. 189 * 190 * This code peeks inside the input buffer in order to avoid actually 191 * reading any input. It would benefit from a rewrite. 192 */ 193 194 #define NEWARGS 5 195 196 STATIC void 197 execinterp(argv, envp) 198 char **argv, **envp; 199 { 200 int n; 201 char *inp; 202 char *outp; 203 char c; 204 char *p; 205 char **ap; 206 char *newargs[NEWARGS]; 207 int i; 208 char **ap2; 209 char **new; 210 211 n = parsenleft - 2; 212 inp = parsenextc + 2; 213 ap = newargs; 214 for (;;) { 215 while (--n >= 0 && (*inp == ' ' || *inp == '\t')) 216 inp++; 217 if (n < 0) 218 goto bad; 219 if ((c = *inp++) == '\n') 220 break; 221 if (ap == &newargs[NEWARGS]) 222 bad: error("Bad #! line"); 223 STARTSTACKSTR(outp); 224 do { 225 STPUTC(c, outp); 226 } while (--n >= 0 && (c = *inp++) != ' ' && c != '\t' && c != '\n'); 227 STPUTC('\0', outp); 228 n++, inp--; 229 *ap++ = grabstackstr(outp); 230 } 231 if (ap == newargs + 1) { /* if no args, maybe no exec is needed */ 232 p = newargs[0]; 233 for (;;) { 234 if (equal(p, "sh") || equal(p, "ash")) { 235 return; 236 } 237 while (*p != '/') { 238 if (*p == '\0') 239 goto break2; 240 p++; 241 } 242 p++; 243 } 244 break2:; 245 } 246 i = (char *)ap - (char *)newargs; /* size in bytes */ 247 if (i == 0) 248 error("Bad #! line"); 249 for (ap2 = argv ; *ap2++ != NULL ; ); 250 new = ckmalloc(i + ((char *)ap2 - (char *)argv)); 251 ap = newargs, ap2 = new; 252 while ((i -= sizeof (char **)) >= 0) 253 *ap2++ = *ap++; 254 ap = argv; 255 while (*ap2++ = *ap++); 256 shellexec(new, envp, pathval(), 0); 257 } 258 #endif 259 260 261 262 /* 263 * Do a path search. The variable path (passed by reference) should be 264 * set to the start of the path before the first call; padvance will update 265 * this value as it proceeds. Successive calls to padvance will return 266 * the possible path expansions in sequence. If an option (indicated by 267 * a percent sign) appears in the path entry then the global variable 268 * pathopt will be set to point to it; otherwise pathopt will be set to 269 * NULL. 270 */ 271 272 char *pathopt; 273 274 char * 275 padvance(path, name) 276 char **path; 277 char *name; 278 { 279 register char *p, *q; 280 char *start; 281 int len; 282 283 if (*path == NULL) 284 return NULL; 285 start = *path; 286 for (p = start ; *p && *p != ':' && *p != '%' ; p++); 287 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */ 288 while (stackblocksize() < len) 289 growstackblock(); 290 q = stackblock(); 291 if (p != start) { 292 bcopy(start, q, p - start); 293 q += p - start; 294 *q++ = '/'; 295 } 296 strcpy(q, name); 297 pathopt = NULL; 298 if (*p == '%') { 299 pathopt = ++p; 300 while (*p && *p != ':') p++; 301 } 302 if (*p == ':') 303 *path = p + 1; 304 else 305 *path = NULL; 306 return stalloc(len); 307 } 308 309 310 311 /*** Command hashing code ***/ 312 313 314 hashcmd(argc, argv) char **argv; { 315 struct tblentry **pp; 316 struct tblentry *cmdp; 317 int c; 318 int verbose; 319 struct cmdentry entry; 320 char *name; 321 322 if (argc <= 1) { 323 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 324 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 325 printentry(cmdp); 326 } 327 } 328 return 0; 329 } 330 verbose = 0; 331 while ((c = nextopt("rv")) != '\0') { 332 if (c == 'r') { 333 clearcmdentry(0); 334 } else if (c == 'v') { 335 verbose++; 336 } 337 } 338 while ((name = *argptr) != NULL) { 339 if ((cmdp = cmdlookup(name, 0)) != NULL 340 && (cmdp->cmdtype == CMDNORMAL 341 || cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)) 342 delete_cmd_entry(); 343 find_command(name, &entry, 1); 344 if (verbose) { 345 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */ 346 cmdp = cmdlookup(name, 0); 347 printentry(cmdp); 348 } 349 flushall(); 350 } 351 argptr++; 352 } 353 return 0; 354 } 355 356 357 STATIC void 358 printentry(cmdp) 359 struct tblentry *cmdp; 360 { 361 int index; 362 char *path; 363 char *name; 364 365 if (cmdp->cmdtype == CMDNORMAL) { 366 index = cmdp->param.index; 367 path = pathval(); 368 do { 369 name = padvance(&path, cmdp->cmdname); 370 stunalloc(name); 371 } while (--index >= 0); 372 out1str(name); 373 } else if (cmdp->cmdtype == CMDBUILTIN) { 374 out1fmt("builtin %s", cmdp->cmdname); 375 } else if (cmdp->cmdtype == CMDFUNCTION) { 376 out1fmt("function %s", cmdp->cmdname); 377 #ifdef DEBUG 378 } else { 379 error("internal error: cmdtype %d", cmdp->cmdtype); 380 #endif 381 } 382 if (cmdp->rehash) 383 out1c('*'); 384 out1c('\n'); 385 } 386 387 388 389 /* 390 * Resolve a command name. If you change this routine, you may have to 391 * change the shellexec routine as well. 392 */ 393 394 void 395 find_command(name, entry, printerr) 396 char *name; 397 struct cmdentry *entry; 398 { 399 struct tblentry *cmdp; 400 int index; 401 int prev; 402 char *path; 403 char *fullname; 404 struct stat statb; 405 int e; 406 int i; 407 408 /* If name contains a slash, don't use the hash table */ 409 if (strchr(name, '/') != NULL) { 410 entry->cmdtype = CMDNORMAL; 411 entry->u.index = 0; 412 return; 413 } 414 415 /* If name is in the table, and not invalidated by cd, we're done */ 416 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) 417 goto success; 418 419 /* If %builtin not in path, check for builtin next */ 420 if (builtinloc < 0 && (i = find_builtin(name)) >= 0) { 421 INTOFF; 422 cmdp = cmdlookup(name, 1); 423 cmdp->cmdtype = CMDBUILTIN; 424 cmdp->param.index = i; 425 INTON; 426 goto success; 427 } 428 429 /* We have to search path. */ 430 prev = -1; /* where to start */ 431 if (cmdp) { /* doing a rehash */ 432 if (cmdp->cmdtype == CMDBUILTIN) 433 prev = builtinloc; 434 else 435 prev = cmdp->param.index; 436 } 437 438 path = pathval(); 439 e = ENOENT; 440 index = -1; 441 loop: 442 while ((fullname = padvance(&path, name)) != NULL) { 443 stunalloc(fullname); 444 index++; 445 if (pathopt) { 446 if (prefix("builtin", pathopt)) { 447 if ((i = find_builtin(name)) < 0) 448 goto loop; 449 INTOFF; 450 cmdp = cmdlookup(name, 1); 451 cmdp->cmdtype = CMDBUILTIN; 452 cmdp->param.index = i; 453 INTON; 454 goto success; 455 } else if (prefix("func", pathopt)) { 456 /* handled below */ 457 } else { 458 goto loop; /* ignore unimplemented options */ 459 } 460 } 461 /* if rehash, don't redo absolute path names */ 462 if (fullname[0] == '/' && index <= prev) { 463 if (index < prev) 464 goto loop; 465 TRACE(("searchexec \"%s\": no change\n", name)); 466 goto success; 467 } 468 while (stat(fullname, &statb) < 0) { 469 #ifdef SYSV 470 if (errno == EINTR) 471 continue; 472 #endif 473 if (errno != ENOENT && errno != ENOTDIR) 474 e = errno; 475 goto loop; 476 } 477 e = EACCES; /* if we fail, this will be the error */ 478 if ((statb.st_mode & S_IFMT) != S_IFREG) 479 goto loop; 480 if (pathopt) { /* this is a %func directory */ 481 stalloc(strlen(fullname) + 1); 482 readcmdfile(fullname); 483 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 484 error("%s not defined in %s", name, fullname); 485 stunalloc(fullname); 486 goto success; 487 } 488 if (statb.st_uid == geteuid()) { 489 if ((statb.st_mode & 0100) == 0) 490 goto loop; 491 } else if (statb.st_gid == getegid()) { 492 if ((statb.st_mode & 010) == 0) 493 goto loop; 494 } else { 495 if ((statb.st_mode & 01) == 0) { 496 #ifdef BSD 497 if ((statb.st_mode & 010) == 0) 498 goto loop; 499 /* Are you in this group too? */ 500 { 501 int group_list[NGROUPS]; 502 int ngroups, i; 503 504 ngroups = getgroups(NGROUPS, group_list); 505 for (i = 0; i < ngroups; i++) 506 if (statb.st_gid == group_list[i]) 507 goto Found; 508 } 509 #endif 510 goto loop; 511 } 512 } 513 #ifdef BSD 514 Found: 515 #endif 516 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 517 INTOFF; 518 cmdp = cmdlookup(name, 1); 519 cmdp->cmdtype = CMDNORMAL; 520 cmdp->param.index = index; 521 INTON; 522 goto success; 523 } 524 525 /* We failed. If there was an entry for this command, delete it */ 526 if (cmdp) 527 delete_cmd_entry(); 528 if (printerr) 529 outfmt(out2, "%s: %s\n", name, errmsg(e, E_EXEC)); 530 entry->cmdtype = CMDUNKNOWN; 531 return; 532 533 success: 534 cmdp->rehash = 0; 535 entry->cmdtype = cmdp->cmdtype; 536 entry->u = cmdp->param; 537 } 538 539 540 541 /* 542 * Search the table of builtin commands. 543 */ 544 545 int 546 find_builtin(name) 547 char *name; 548 { 549 const register struct builtincmd *bp; 550 551 for (bp = builtincmd ; bp->name ; bp++) { 552 if (*bp->name == *name && equal(bp->name, name)) 553 return bp->code; 554 } 555 return -1; 556 } 557 558 559 560 /* 561 * Called when a cd is done. Marks all commands so the next time they 562 * are executed they will be rehashed. 563 */ 564 565 void 566 hashcd() { 567 struct tblentry **pp; 568 struct tblentry *cmdp; 569 570 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 571 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 572 if (cmdp->cmdtype == CMDNORMAL 573 || cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0) 574 cmdp->rehash = 1; 575 } 576 } 577 } 578 579 580 581 /* 582 * Called before PATH is changed. The argument is the new value of PATH; 583 * pathval() still returns the old value at this point. Called with 584 * interrupts off. 585 */ 586 587 void 588 changepath(newval) 589 char *newval; 590 { 591 char *old, *new; 592 int index; 593 int firstchange; 594 int bltin; 595 596 old = pathval(); 597 new = newval; 598 firstchange = 9999; /* assume no change */ 599 index = 0; 600 bltin = -1; 601 for (;;) { 602 if (*old != *new) { 603 firstchange = index; 604 if (*old == '\0' && *new == ':' 605 || *old == ':' && *new == '\0') 606 firstchange++; 607 old = new; /* ignore subsequent differences */ 608 } 609 if (*new == '\0') 610 break; 611 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1)) 612 bltin = index; 613 if (*new == ':') { 614 index++; 615 } 616 new++, old++; 617 } 618 if (builtinloc < 0 && bltin >= 0) 619 builtinloc = bltin; /* zap builtins */ 620 if (builtinloc >= 0 && bltin < 0) 621 firstchange = 0; 622 clearcmdentry(firstchange); 623 builtinloc = bltin; 624 } 625 626 627 /* 628 * Clear out command entries. The argument specifies the first entry in 629 * PATH which has changed. 630 */ 631 632 STATIC void 633 clearcmdentry(firstchange) { 634 struct tblentry **tblp; 635 struct tblentry **pp; 636 struct tblentry *cmdp; 637 638 INTOFF; 639 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 640 pp = tblp; 641 while ((cmdp = *pp) != NULL) { 642 if (cmdp->cmdtype == CMDNORMAL && cmdp->param.index >= firstchange 643 || cmdp->cmdtype == CMDBUILTIN && builtinloc >= firstchange) { 644 *pp = cmdp->next; 645 ckfree(cmdp); 646 } else { 647 pp = &cmdp->next; 648 } 649 } 650 } 651 INTON; 652 } 653 654 655 /* 656 * Delete all functions. 657 */ 658 659 #ifdef mkinit 660 MKINIT void deletefuncs(); 661 662 SHELLPROC { 663 deletefuncs(); 664 } 665 #endif 666 667 void 668 deletefuncs() { 669 struct tblentry **tblp; 670 struct tblentry **pp; 671 struct tblentry *cmdp; 672 673 INTOFF; 674 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 675 pp = tblp; 676 while ((cmdp = *pp) != NULL) { 677 if (cmdp->cmdtype == CMDFUNCTION) { 678 *pp = cmdp->next; 679 freefunc(cmdp->param.func); 680 ckfree(cmdp); 681 } else { 682 pp = &cmdp->next; 683 } 684 } 685 } 686 INTON; 687 } 688 689 690 691 /* 692 * Locate a command in the command hash table. If "add" is nonzero, 693 * add the command to the table if it is not already present. The 694 * variable "lastcmdentry" is set to point to the address of the link 695 * pointing to the entry, so that delete_cmd_entry can delete the 696 * entry. 697 */ 698 699 struct tblentry **lastcmdentry; 700 701 702 STATIC struct tblentry * 703 cmdlookup(name, add) 704 char *name; 705 { 706 int hashval; 707 register char *p; 708 struct tblentry *cmdp; 709 struct tblentry **pp; 710 711 p = name; 712 hashval = *p << 4; 713 while (*p) 714 hashval += *p++; 715 hashval &= 0x7FFF; 716 pp = &cmdtable[hashval % CMDTABLESIZE]; 717 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 718 if (equal(cmdp->cmdname, name)) 719 break; 720 pp = &cmdp->next; 721 } 722 if (add && cmdp == NULL) { 723 INTOFF; 724 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB 725 + strlen(name) + 1); 726 cmdp->next = NULL; 727 cmdp->cmdtype = CMDUNKNOWN; 728 cmdp->rehash = 0; 729 strcpy(cmdp->cmdname, name); 730 INTON; 731 } 732 lastcmdentry = pp; 733 return cmdp; 734 } 735 736 737 /* 738 * Delete the command entry returned on the last lookup. 739 */ 740 741 STATIC void 742 delete_cmd_entry() { 743 struct tblentry *cmdp; 744 745 INTOFF; 746 cmdp = *lastcmdentry; 747 *lastcmdentry = cmdp->next; 748 ckfree(cmdp); 749 INTON; 750 } 751 752 753 754 #ifdef notdef 755 void 756 getcmdentry(name, entry) 757 char *name; 758 struct cmdentry *entry; 759 { 760 struct tblentry *cmdp = cmdlookup(name, 0); 761 762 if (cmdp) { 763 entry->u = cmdp->param; 764 entry->cmdtype = cmdp->cmdtype; 765 } else { 766 entry->cmdtype = CMDUNKNOWN; 767 entry->u.index = 0; 768 } 769 } 770 #endif 771 772 773 /* 774 * Add a new command entry, replacing any existing command entry for 775 * the same name. 776 */ 777 778 void 779 addcmdentry(name, entry) 780 char *name; 781 struct cmdentry *entry; 782 { 783 struct tblentry *cmdp; 784 785 INTOFF; 786 cmdp = cmdlookup(name, 1); 787 if (cmdp->cmdtype == CMDFUNCTION) { 788 freefunc(cmdp->param.func); 789 } 790 cmdp->cmdtype = entry->cmdtype; 791 cmdp->param = entry->u; 792 INTON; 793 } 794 795 796 /* 797 * Define a shell function. 798 */ 799 800 void 801 defun(name, func) 802 char *name; 803 union node *func; 804 { 805 struct cmdentry entry; 806 807 INTOFF; 808 entry.cmdtype = CMDFUNCTION; 809 entry.u.func = copyfunc(func); 810 addcmdentry(name, &entry); 811 INTON; 812 } 813 814 815 /* 816 * Delete a function if it exists. 817 */ 818 819 void 820 unsetfunc(name) 821 char *name; 822 { 823 struct tblentry *cmdp; 824 825 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 826 freefunc(cmdp->param.func); 827 delete_cmd_entry(); 828 } 829 } 830