exec.c revision 218242
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 35static char sccsid[] = "@(#)exec.c 8.4 (Berkeley) 6/8/95"; 36#endif 37#endif /* not lint */ 38#include <sys/cdefs.h> 39__FBSDID("$FreeBSD: head/bin/sh/exec.c 218242 2011-02-03 23:38:11Z jilles $"); 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 <stdlib.h> 47 48/* 49 * When commands are first encountered, they are entered in a hash table. 50 * This ensures that a full path search will not have to be done for them 51 * on each invocation. 52 * 53 * We should investigate converting to a linear search, even though that 54 * would make the command name "hash" a misnomer. 55 */ 56 57#include "shell.h" 58#include "main.h" 59#include "nodes.h" 60#include "parser.h" 61#include "redir.h" 62#include "eval.h" 63#include "exec.h" 64#include "builtins.h" 65#include "var.h" 66#include "options.h" 67#include "input.h" 68#include "output.h" 69#include "syntax.h" 70#include "memalloc.h" 71#include "error.h" 72#include "init.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#define ARB 1 /* actual size determined at run time */ 81 82 83 84struct tblentry { 85 struct tblentry *next; /* next entry in hash chain */ 86 union param param; /* definition of builtin function */ 87 int special; /* flag for special builtin commands */ 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 94static struct tblentry *cmdtable[CMDTABLESIZE]; 95int exerrno = 0; /* Last exec error */ 96 97 98static void tryexec(char *, char **, char **); 99static void printentry(struct tblentry *, int); 100static struct tblentry *cmdlookup(const char *, int); 101static void delete_cmd_entry(void); 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 110void 111shellexec(char **argv, char **envp, const char *path, int idx) 112{ 113 char *cmdname; 114 int e; 115 116 if (strchr(argv[0], '/') != NULL) { 117 tryexec(argv[0], argv, envp); 118 e = errno; 119 } else { 120 e = ENOENT; 121 while ((cmdname = padvance(&path, argv[0])) != NULL) { 122 if (--idx < 0 && pathopt == NULL) { 123 tryexec(cmdname, argv, envp); 124 if (errno != ENOENT && errno != ENOTDIR) 125 e = errno; 126 } 127 stunalloc(cmdname); 128 } 129 } 130 131 /* Map to POSIX errors */ 132 if (e == ENOENT || e == ENOTDIR) { 133 exerrno = 127; 134 exerror(EXEXEC, "%s: not found", argv[0]); 135 } else { 136 exerrno = 126; 137 exerror(EXEXEC, "%s: %s", argv[0], strerror(e)); 138 } 139} 140 141 142static void 143tryexec(char *cmd, char **argv, char **envp) 144{ 145 int e; 146 147 execve(cmd, argv, envp); 148 e = errno; 149 if (e == ENOEXEC) { 150 initshellproc(); 151 setinputfile(cmd, 0); 152 commandname = arg0 = savestr(argv[0]); 153 setparam(argv + 1); 154 exraise(EXSHELLPROC); 155 /*NOTREACHED*/ 156 } 157 errno = e; 158} 159 160/* 161 * Do a path search. The variable path (passed by reference) should be 162 * set to the start of the path before the first call; padvance will update 163 * this value as it proceeds. Successive calls to padvance will return 164 * the possible path expansions in sequence. If an option (indicated by 165 * a percent sign) appears in the path entry then the global variable 166 * pathopt will be set to point to it; otherwise pathopt will be set to 167 * NULL. 168 */ 169 170const char *pathopt; 171 172char * 173padvance(const char **path, const char *name) 174{ 175 const char *p, *start; 176 char *q; 177 int len; 178 179 if (*path == NULL) 180 return NULL; 181 start = *path; 182 for (p = start; *p && *p != ':' && *p != '%'; p++) 183 ; /* nothing */ 184 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */ 185 STARTSTACKSTR(q); 186 CHECKSTRSPACE(len, q); 187 if (p != start) { 188 memcpy(q, start, p - start); 189 q += p - start; 190 *q++ = '/'; 191 } 192 strcpy(q, name); 193 pathopt = NULL; 194 if (*p == '%') { 195 pathopt = ++p; 196 while (*p && *p != ':') p++; 197 } 198 if (*p == ':') 199 *path = p + 1; 200 else 201 *path = NULL; 202 return stalloc(len); 203} 204 205 206 207/*** Command hashing code ***/ 208 209 210int 211hashcmd(int argc __unused, char **argv __unused) 212{ 213 struct tblentry **pp; 214 struct tblentry *cmdp; 215 int c; 216 int verbose; 217 struct cmdentry entry; 218 char *name; 219 220 verbose = 0; 221 while ((c = nextopt("rv")) != '\0') { 222 if (c == 'r') { 223 clearcmdentry(0); 224 } else if (c == 'v') { 225 verbose++; 226 } 227 } 228 if (*argptr == NULL) { 229 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 230 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 231 if (cmdp->cmdtype == CMDNORMAL) 232 printentry(cmdp, verbose); 233 } 234 } 235 return 0; 236 } 237 while ((name = *argptr) != NULL) { 238 if ((cmdp = cmdlookup(name, 0)) != NULL 239 && cmdp->cmdtype == CMDNORMAL) 240 delete_cmd_entry(); 241 find_command(name, &entry, DO_ERR, pathval()); 242 if (verbose) { 243 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */ 244 cmdp = cmdlookup(name, 0); 245 if (cmdp != NULL) 246 printentry(cmdp, verbose); 247 else 248 outfmt(out2, "%s: not found\n", name); 249 } 250 flushall(); 251 } 252 argptr++; 253 } 254 return 0; 255} 256 257 258static void 259printentry(struct tblentry *cmdp, int verbose) 260{ 261 int idx; 262 const char *path; 263 char *name; 264 265 if (cmdp->cmdtype == CMDNORMAL) { 266 idx = cmdp->param.index; 267 path = pathval(); 268 do { 269 name = padvance(&path, cmdp->cmdname); 270 stunalloc(name); 271 } while (--idx >= 0); 272 out1str(name); 273 } else if (cmdp->cmdtype == CMDBUILTIN) { 274 out1fmt("builtin %s", cmdp->cmdname); 275 } else if (cmdp->cmdtype == CMDFUNCTION) { 276 out1fmt("function %s", cmdp->cmdname); 277 if (verbose) { 278 INTOFF; 279 name = commandtext(getfuncnode(cmdp->param.func)); 280 out1c(' '); 281 out1str(name); 282 ckfree(name); 283 INTON; 284 } 285#ifdef DEBUG 286 } else { 287 error("internal error: cmdtype %d", cmdp->cmdtype); 288#endif 289 } 290 if (cmdp->rehash) 291 out1c('*'); 292 out1c('\n'); 293} 294 295 296 297/* 298 * Resolve a command name. If you change this routine, you may have to 299 * change the shellexec routine as well. 300 */ 301 302void 303find_command(const char *name, struct cmdentry *entry, int act, 304 const char *path) 305{ 306 struct tblentry *cmdp, loc_cmd; 307 int idx; 308 int prev; 309 char *fullname; 310 struct stat statb; 311 int e; 312 int i; 313 int spec; 314 315 /* If name contains a slash, don't use the hash table */ 316 if (strchr(name, '/') != NULL) { 317 entry->cmdtype = CMDNORMAL; 318 entry->u.index = 0; 319 return; 320 } 321 322 /* If name is in the table, and not invalidated by cd, we're done */ 323 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) { 324 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC) 325 cmdp = NULL; 326 else 327 goto success; 328 } 329 330 /* Check for builtin next */ 331 if ((i = find_builtin(name, &spec)) >= 0) { 332 INTOFF; 333 cmdp = cmdlookup(name, 1); 334 if (cmdp->cmdtype == CMDFUNCTION) 335 cmdp = &loc_cmd; 336 cmdp->cmdtype = CMDBUILTIN; 337 cmdp->param.index = i; 338 cmdp->special = spec; 339 INTON; 340 goto success; 341 } 342 343 /* We have to search path. */ 344 prev = -1; /* where to start */ 345 if (cmdp) { /* doing a rehash */ 346 if (cmdp->cmdtype == CMDBUILTIN) 347 prev = -1; 348 else 349 prev = cmdp->param.index; 350 } 351 352 e = ENOENT; 353 idx = -1; 354loop: 355 while ((fullname = padvance(&path, name)) != NULL) { 356 stunalloc(fullname); 357 idx++; 358 if (pathopt) { 359 if (prefix("func", pathopt)) { 360 /* handled below */ 361 } else { 362 goto loop; /* ignore unimplemented options */ 363 } 364 } 365 /* if rehash, don't redo absolute path names */ 366 if (fullname[0] == '/' && idx <= prev) { 367 if (idx < prev) 368 goto loop; 369 TRACE(("searchexec \"%s\": no change\n", name)); 370 goto success; 371 } 372 if (stat(fullname, &statb) < 0) { 373 if (errno != ENOENT && errno != ENOTDIR) 374 e = errno; 375 goto loop; 376 } 377 e = EACCES; /* if we fail, this will be the error */ 378 if (!S_ISREG(statb.st_mode)) 379 goto loop; 380 if (pathopt) { /* this is a %func directory */ 381 stalloc(strlen(fullname) + 1); 382 readcmdfile(fullname); 383 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) 384 error("%s not defined in %s", name, fullname); 385 stunalloc(fullname); 386 goto success; 387 } 388#ifdef notdef 389 if (statb.st_uid == geteuid()) { 390 if ((statb.st_mode & 0100) == 0) 391 goto loop; 392 } else if (statb.st_gid == getegid()) { 393 if ((statb.st_mode & 010) == 0) 394 goto loop; 395 } else { 396 if ((statb.st_mode & 01) == 0) 397 goto loop; 398 } 399#endif 400 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); 401 INTOFF; 402 cmdp = cmdlookup(name, 1); 403 if (cmdp->cmdtype == CMDFUNCTION) 404 cmdp = &loc_cmd; 405 cmdp->cmdtype = CMDNORMAL; 406 cmdp->param.index = idx; 407 INTON; 408 goto success; 409 } 410 411 /* We failed. If there was an entry for this command, delete it */ 412 if (cmdp && cmdp->cmdtype != CMDFUNCTION) 413 delete_cmd_entry(); 414 if (act & DO_ERR) { 415 if (e == ENOENT || e == ENOTDIR) 416 outfmt(out2, "%s: not found\n", name); 417 else 418 outfmt(out2, "%s: %s\n", name, strerror(e)); 419 } 420 entry->cmdtype = CMDUNKNOWN; 421 entry->u.index = 0; 422 return; 423 424success: 425 cmdp->rehash = 0; 426 entry->cmdtype = cmdp->cmdtype; 427 entry->u = cmdp->param; 428 entry->special = cmdp->special; 429} 430 431 432 433/* 434 * Search the table of builtin commands. 435 */ 436 437int 438find_builtin(const char *name, int *special) 439{ 440 const struct builtincmd *bp; 441 442 for (bp = builtincmd ; bp->name ; bp++) { 443 if (*bp->name == *name && equal(bp->name, name)) { 444 *special = bp->special; 445 return bp->code; 446 } 447 } 448 return -1; 449} 450 451 452 453/* 454 * Called when a cd is done. Marks all commands so the next time they 455 * are executed they will be rehashed. 456 */ 457 458void 459hashcd(void) 460{ 461 struct tblentry **pp; 462 struct tblentry *cmdp; 463 464 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { 465 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 466 if (cmdp->cmdtype == CMDNORMAL) 467 cmdp->rehash = 1; 468 } 469 } 470} 471 472 473 474/* 475 * Called before PATH is changed. The argument is the new value of PATH; 476 * pathval() still returns the old value at this point. Called with 477 * interrupts off. 478 */ 479 480void 481changepath(const char *newval) 482{ 483 const char *old, *new; 484 int idx; 485 int firstchange; 486 487 old = pathval(); 488 new = newval; 489 firstchange = 9999; /* assume no change */ 490 idx = 0; 491 for (;;) { 492 if (*old != *new) { 493 firstchange = idx; 494 if ((*old == '\0' && *new == ':') 495 || (*old == ':' && *new == '\0')) 496 firstchange++; 497 old = new; /* ignore subsequent differences */ 498 } 499 if (*new == '\0') 500 break; 501 if (*new == ':') { 502 idx++; 503 } 504 new++, old++; 505 } 506 clearcmdentry(firstchange); 507} 508 509 510/* 511 * Clear out command entries. The argument specifies the first entry in 512 * PATH which has changed. 513 */ 514 515void 516clearcmdentry(int firstchange) 517{ 518 struct tblentry **tblp; 519 struct tblentry **pp; 520 struct tblentry *cmdp; 521 522 INTOFF; 523 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 524 pp = tblp; 525 while ((cmdp = *pp) != NULL) { 526 if ((cmdp->cmdtype == CMDNORMAL && 527 cmdp->param.index >= firstchange)) { 528 *pp = cmdp->next; 529 ckfree(cmdp); 530 } else { 531 pp = &cmdp->next; 532 } 533 } 534 } 535 INTON; 536} 537 538 539/* 540 * Delete all functions. 541 */ 542 543#ifdef mkinit 544MKINIT void deletefuncs(void); 545 546SHELLPROC { 547 deletefuncs(); 548} 549#endif 550 551void 552deletefuncs(void) 553{ 554 struct tblentry **tblp; 555 struct tblentry **pp; 556 struct tblentry *cmdp; 557 558 INTOFF; 559 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { 560 pp = tblp; 561 while ((cmdp = *pp) != NULL) { 562 if (cmdp->cmdtype == CMDFUNCTION) { 563 *pp = cmdp->next; 564 unreffunc(cmdp->param.func); 565 ckfree(cmdp); 566 } else { 567 pp = &cmdp->next; 568 } 569 } 570 } 571 INTON; 572} 573 574 575 576/* 577 * Locate a command in the command hash table. If "add" is nonzero, 578 * add the command to the table if it is not already present. The 579 * variable "lastcmdentry" is set to point to the address of the link 580 * pointing to the entry, so that delete_cmd_entry can delete the 581 * entry. 582 */ 583 584static struct tblentry **lastcmdentry; 585 586 587static struct tblentry * 588cmdlookup(const char *name, int add) 589{ 590 int hashval; 591 const char *p; 592 struct tblentry *cmdp; 593 struct tblentry **pp; 594 595 p = name; 596 hashval = *p << 4; 597 while (*p) 598 hashval += *p++; 599 hashval &= 0x7FFF; 600 pp = &cmdtable[hashval % CMDTABLESIZE]; 601 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { 602 if (equal(cmdp->cmdname, name)) 603 break; 604 pp = &cmdp->next; 605 } 606 if (add && cmdp == NULL) { 607 INTOFF; 608 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB 609 + strlen(name) + 1); 610 cmdp->next = NULL; 611 cmdp->cmdtype = CMDUNKNOWN; 612 cmdp->rehash = 0; 613 strcpy(cmdp->cmdname, name); 614 INTON; 615 } 616 lastcmdentry = pp; 617 return cmdp; 618} 619 620/* 621 * Delete the command entry returned on the last lookup. 622 */ 623 624static void 625delete_cmd_entry(void) 626{ 627 struct tblentry *cmdp; 628 629 INTOFF; 630 cmdp = *lastcmdentry; 631 *lastcmdentry = cmdp->next; 632 ckfree(cmdp); 633 INTON; 634} 635 636 637 638/* 639 * Add a new command entry, replacing any existing command entry for 640 * the same name. 641 */ 642 643void 644addcmdentry(const char *name, struct cmdentry *entry) 645{ 646 struct tblentry *cmdp; 647 648 INTOFF; 649 cmdp = cmdlookup(name, 1); 650 if (cmdp->cmdtype == CMDFUNCTION) { 651 unreffunc(cmdp->param.func); 652 } 653 cmdp->cmdtype = entry->cmdtype; 654 cmdp->param = entry->u; 655 INTON; 656} 657 658 659/* 660 * Define a shell function. 661 */ 662 663void 664defun(const char *name, union node *func) 665{ 666 struct cmdentry entry; 667 668 INTOFF; 669 entry.cmdtype = CMDFUNCTION; 670 entry.u.func = copyfunc(func); 671 addcmdentry(name, &entry); 672 INTON; 673} 674 675 676/* 677 * Delete a function if it exists. 678 */ 679 680int 681unsetfunc(const char *name) 682{ 683 struct tblentry *cmdp; 684 685 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { 686 unreffunc(cmdp->param.func); 687 delete_cmd_entry(); 688 return (0); 689 } 690 return (0); 691} 692 693/* 694 * Shared code for the following builtin commands: 695 * type, command -v, command -V 696 */ 697 698int 699typecmd_impl(int argc, char **argv, int cmd, const char *path) 700{ 701 struct cmdentry entry; 702 struct tblentry *cmdp; 703 const char *const *pp; 704 struct alias *ap; 705 int i; 706 int error1 = 0; 707 708 if (path != pathval()) 709 clearcmdentry(0); 710 711 for (i = 1; i < argc; i++) { 712 /* First look at the keywords */ 713 for (pp = parsekwd; *pp; pp++) 714 if (**pp == *argv[i] && equal(*pp, argv[i])) 715 break; 716 717 if (*pp) { 718 if (cmd == TYPECMD_SMALLV) 719 out1fmt("%s\n", argv[i]); 720 else 721 out1fmt("%s is a shell keyword\n", argv[i]); 722 continue; 723 } 724 725 /* Then look at the aliases */ 726 if ((ap = lookupalias(argv[i], 1)) != NULL) { 727 if (cmd == TYPECMD_SMALLV) 728 out1fmt("alias %s='%s'\n", argv[i], ap->val); 729 else 730 out1fmt("%s is an alias for %s\n", argv[i], 731 ap->val); 732 continue; 733 } 734 735 /* Then check if it is a tracked alias */ 736 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) { 737 entry.cmdtype = cmdp->cmdtype; 738 entry.u = cmdp->param; 739 entry.special = cmdp->special; 740 } 741 else { 742 /* Finally use brute force */ 743 find_command(argv[i], &entry, 0, path); 744 } 745 746 switch (entry.cmdtype) { 747 case CMDNORMAL: { 748 if (strchr(argv[i], '/') == NULL) { 749 const char *path2 = path; 750 char *name; 751 int j = entry.u.index; 752 do { 753 name = padvance(&path2, argv[i]); 754 stunalloc(name); 755 } while (--j >= 0); 756 if (cmd == TYPECMD_SMALLV) 757 out1fmt("%s\n", name); 758 else 759 out1fmt("%s is%s %s\n", argv[i], 760 (cmdp && cmd == TYPECMD_TYPE) ? 761 " a tracked alias for" : "", 762 name); 763 } else { 764 if (eaccess(argv[i], X_OK) == 0) { 765 if (cmd == TYPECMD_SMALLV) 766 out1fmt("%s\n", argv[i]); 767 else 768 out1fmt("%s is %s\n", argv[i], 769 argv[i]); 770 } else { 771 if (cmd != TYPECMD_SMALLV) 772 outfmt(out2, "%s: %s\n", 773 argv[i], strerror(errno)); 774 error1 |= 127; 775 } 776 } 777 break; 778 } 779 case CMDFUNCTION: 780 if (cmd == TYPECMD_SMALLV) 781 out1fmt("%s\n", argv[i]); 782 else 783 out1fmt("%s is a shell function\n", argv[i]); 784 break; 785 786 case CMDBUILTIN: 787 if (cmd == TYPECMD_SMALLV) 788 out1fmt("%s\n", argv[i]); 789 else if (entry.special) 790 out1fmt("%s is a special shell builtin\n", 791 argv[i]); 792 else 793 out1fmt("%s is a shell builtin\n", argv[i]); 794 break; 795 796 default: 797 if (cmd != TYPECMD_SMALLV) 798 outfmt(out2, "%s: not found\n", argv[i]); 799 error1 |= 127; 800 break; 801 } 802 } 803 804 if (path != pathval()) 805 clearcmdentry(0); 806 807 return error1; 808} 809 810/* 811 * Locate and print what a word is... 812 */ 813 814int 815typecmd(int argc, char **argv) 816{ 817 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1)); 818} 819