| 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 | * %sccs.include.redist.c% |
| 9 | */ |
| 10 | |
| 11 | #ifndef lint |
| 12 | static char sccsid[] = "@(#)exec.c 5.1 (Berkeley) %G%"; |
| 13 | #endif /* not lint */ |
| 14 | |
| 15 | /* |
| 16 | * When commands are first encountered, they are entered in a hash table. |
| 17 | * This ensures that a full path search will not have to be done for them |
| 18 | * on each invocation. |
| 19 | * |
| 20 | * We should investigate converting to a linear search, even though that |
| 21 | * would make the command name "hash" a misnomer. |
| 22 | */ |
| 23 | |
| 24 | #include "shell.h" |
| 25 | #include "main.h" |
| 26 | #include "nodes.h" |
| 27 | #include "parser.h" |
| 28 | #include "redir.h" |
| 29 | #include "eval.h" |
| 30 | #include "exec.h" |
| 31 | #include "builtins.h" |
| 32 | #include "var.h" |
| 33 | #include "options.h" |
| 34 | #include "input.h" |
| 35 | #include "output.h" |
| 36 | #include "syntax.h" |
| 37 | #include "memalloc.h" |
| 38 | #include "error.h" |
| 39 | #include "init.h" |
| 40 | #include "mystring.h" |
| 41 | #include <sys/types.h> |
| 42 | #include <sys/stat.h> |
| 43 | #include <fcntl.h> |
| 44 | #include <errno.h> |
| 45 | |
| 46 | |
| 47 | #define CMDTABLESIZE 31 /* should be prime */ |
| 48 | #define ARB 1 /* actual size determined at run time */ |
| 49 | |
| 50 | |
| 51 | |
| 52 | struct tblentry { |
| 53 | struct tblentry *next; /* next entry in hash chain */ |
| 54 | union param param; /* definition of builtin function */ |
| 55 | short cmdtype; /* index identifying command */ |
| 56 | char rehash; /* if set, cd done since entry created */ |
| 57 | char cmdname[ARB]; /* name of command */ |
| 58 | }; |
| 59 | |
| 60 | |
| 61 | STATIC struct tblentry *cmdtable[CMDTABLESIZE]; |
| 62 | STATIC int builtinloc; /* index in path of %builtin, or -1 */ |
| 63 | |
| 64 | |
| 65 | #ifdef __STDC__ |
| 66 | STATIC void tryexec(char *, char **, char **); |
| 67 | STATIC void execinterp(char **, char **); |
| 68 | STATIC void printentry(struct tblentry *); |
| 69 | STATIC void clearcmdentry(int); |
| 70 | STATIC struct tblentry *cmdlookup(char *, int); |
| 71 | STATIC void delete_cmd_entry(void); |
| 72 | #else |
| 73 | STATIC void tryexec(); |
| 74 | STATIC void execinterp(); |
| 75 | STATIC void printentry(); |
| 76 | STATIC void clearcmdentry(); |
| 77 | STATIC struct tblentry *cmdlookup(); |
| 78 | STATIC void delete_cmd_entry(); |
| 79 | #endif |
| 80 | |
| 81 | |
| 82 | |
| 83 | /* |
| 84 | * Exec a program. Never returns. If you change this routine, you may |
| 85 | * have to change the find_command routine as well. |
| 86 | */ |
| 87 | |
| 88 | void |
| 89 | shellexec(argv, envp, path, index) |
| 90 | char **argv, **envp; |
| 91 | char *path; |
| 92 | { |
| 93 | char *cmdname; |
| 94 | int e; |
| 95 | |
| 96 | if (strchr(argv[0], '/') != NULL) { |
| 97 | tryexec(argv[0], argv, envp); |
| 98 | e = errno; |
| 99 | } else { |
| 100 | e = ENOENT; |
| 101 | while ((cmdname = padvance(&path, argv[0])) != NULL) { |
| 102 | if (--index < 0 && pathopt == NULL) { |
| 103 | tryexec(cmdname, argv, envp); |
| 104 | if (errno != ENOENT && errno != ENOTDIR) |
| 105 | e = errno; |
| 106 | } |
| 107 | stunalloc(cmdname); |
| 108 | } |
| 109 | } |
| 110 | error2(argv[0], errmsg(e, E_EXEC)); |
| 111 | } |
| 112 | |
| 113 | |
| 114 | STATIC void |
| 115 | tryexec(cmd, argv, envp) |
| 116 | char *cmd; |
| 117 | char **argv; |
| 118 | char **envp; |
| 119 | { |
| 120 | int e; |
| 121 | char *p; |
| 122 | |
| 123 | #ifdef SYSV |
| 124 | do { |
| 125 | execve(cmd, argv, envp); |
| 126 | } while (errno == EINTR); |
| 127 | #else |
| 128 | execve(cmd, argv, envp); |
| 129 | #endif |
| 130 | e = errno; |
| 131 | if (e == ENOEXEC) { |
| 132 | initshellproc(); |
| 133 | setinputfile(cmd, 0); |
| 134 | commandname = arg0 = savestr(argv[0]); |
| 135 | #ifndef BSD |
| 136 | pgetc(); pungetc(); /* fill up input buffer */ |
| 137 | p = parsenextc; |
| 138 | if (parsenleft > 2 && p[0] == '#' && p[1] == '!') { |
| 139 | argv[0] = cmd; |
| 140 | execinterp(argv, envp); |
| 141 | } |
| 142 | #endif |
| 143 | setparam(argv + 1); |
| 144 | exraise(EXSHELLPROC); |
| 145 | /*NOTREACHED*/ |
| 146 | } |
| 147 | errno = e; |
| 148 | } |
| 149 | |
| 150 | |
| 151 | #ifndef BSD |
| 152 | /* |
| 153 | * Execute an interpreter introduced by "#!", for systems where this |
| 154 | * feature has not been built into the kernel. If the interpreter is |
| 155 | * the shell, return (effectively ignoring the "#!"). If the execution |
| 156 | * of the interpreter fails, exit. |
| 157 | * |
| 158 | * This code peeks inside the input buffer in order to avoid actually |
| 159 | * reading any input. It would benefit from a rewrite. |
| 160 | */ |
| 161 | |
| 162 | #define NEWARGS 5 |
| 163 | |
| 164 | STATIC void |
| 165 | execinterp(argv, envp) |
| 166 | char **argv, **envp; |
| 167 | { |
| 168 | int n; |
| 169 | char *inp; |
| 170 | char *outp; |
| 171 | char c; |
| 172 | char *p; |
| 173 | char **ap; |
| 174 | char *newargs[NEWARGS]; |
| 175 | int i; |
| 176 | char **ap2; |
| 177 | char **new; |
| 178 | |
| 179 | n = parsenleft - 2; |
| 180 | inp = parsenextc + 2; |
| 181 | ap = newargs; |
| 182 | for (;;) { |
| 183 | while (--n >= 0 && (*inp == ' ' || *inp == '\t')) |
| 184 | inp++; |
| 185 | if (n < 0) |
| 186 | goto bad; |
| 187 | if ((c = *inp++) == '\n') |
| 188 | break; |
| 189 | if (ap == &newargs[NEWARGS]) |
| 190 | bad: error("Bad #! line"); |
| 191 | STARTSTACKSTR(outp); |
| 192 | do { |
| 193 | STPUTC(c, outp); |
| 194 | } while (--n >= 0 && (c = *inp++) != ' ' && c != '\t' && c != '\n'); |
| 195 | STPUTC('\0', outp); |
| 196 | n++, inp--; |
| 197 | *ap++ = grabstackstr(outp); |
| 198 | } |
| 199 | if (ap == newargs + 1) { /* if no args, maybe no exec is needed */ |
| 200 | p = newargs[0]; |
| 201 | for (;;) { |
| 202 | if (equal(p, "sh") || equal(p, "ash")) { |
| 203 | return; |
| 204 | } |
| 205 | while (*p != '/') { |
| 206 | if (*p == '\0') |
| 207 | goto break2; |
| 208 | p++; |
| 209 | } |
| 210 | p++; |
| 211 | } |
| 212 | break2:; |
| 213 | } |
| 214 | i = (char *)ap - (char *)newargs; /* size in bytes */ |
| 215 | if (i == 0) |
| 216 | error("Bad #! line"); |
| 217 | for (ap2 = argv ; *ap2++ != NULL ; ); |
| 218 | new = ckmalloc(i + ((char *)ap2 - (char *)argv)); |
| 219 | ap = newargs, ap2 = new; |
| 220 | while ((i -= sizeof (char **)) >= 0) |
| 221 | *ap2++ = *ap++; |
| 222 | ap = argv; |
| 223 | while (*ap2++ = *ap++); |
| 224 | shellexec(new, envp, pathval(), 0); |
| 225 | } |
| 226 | #endif |
| 227 | |
| 228 | |
| 229 | |
| 230 | /* |
| 231 | * Do a path search. The variable path (passed by reference) should be |
| 232 | * set to the start of the path before the first call; padvance will update |
| 233 | * this value as it proceeds. Successive calls to padvance will return |
| 234 | * the possible path expansions in sequence. If an option (indicated by |
| 235 | * a percent sign) appears in the path entry then the global variable |
| 236 | * pathopt will be set to point to it; otherwise pathopt will be set to |
| 237 | * NULL. |
| 238 | */ |
| 239 | |
| 240 | char *pathopt; |
| 241 | |
| 242 | char * |
| 243 | padvance(path, name) |
| 244 | char **path; |
| 245 | char *name; |
| 246 | { |
| 247 | register char *p, *q; |
| 248 | char *start; |
| 249 | int len; |
| 250 | |
| 251 | if (*path == NULL) |
| 252 | return NULL; |
| 253 | start = *path; |
| 254 | for (p = start ; *p && *p != ':' && *p != '%' ; p++); |
| 255 | len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */ |
| 256 | while (stackblocksize() < len) |
| 257 | growstackblock(); |
| 258 | q = stackblock(); |
| 259 | if (p != start) { |
| 260 | bcopy(start, q, p - start); |
| 261 | q += p - start; |
| 262 | *q++ = '/'; |
| 263 | } |
| 264 | strcpy(q, name); |
| 265 | pathopt = NULL; |
| 266 | if (*p == '%') { |
| 267 | pathopt = ++p; |
| 268 | while (*p && *p != ':') p++; |
| 269 | } |
| 270 | if (*p == ':') |
| 271 | *path = p + 1; |
| 272 | else |
| 273 | *path = NULL; |
| 274 | return stalloc(len); |
| 275 | } |
| 276 | |
| 277 | |
| 278 | |
| 279 | /*** Command hashing code ***/ |
| 280 | |
| 281 | |
| 282 | hashcmd(argc, argv) char **argv; { |
| 283 | struct tblentry **pp; |
| 284 | struct tblentry *cmdp; |
| 285 | int c; |
| 286 | int verbose; |
| 287 | struct cmdentry entry; |
| 288 | char *name; |
| 289 | |
| 290 | if (argc <= 1) { |
| 291 | for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { |
| 292 | for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { |
| 293 | printentry(cmdp); |
| 294 | } |
| 295 | } |
| 296 | return 0; |
| 297 | } |
| 298 | verbose = 0; |
| 299 | while ((c = nextopt("rv")) >= 0) { |
| 300 | if (c == 'r') { |
| 301 | clearcmdentry(0); |
| 302 | } else if (c == 'v') { |
| 303 | verbose++; |
| 304 | } |
| 305 | } |
| 306 | while ((name = *argptr) != NULL) { |
| 307 | if ((cmdp = cmdlookup(name, 0)) != NULL |
| 308 | && (cmdp->cmdtype == CMDNORMAL |
| 309 | || cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)) |
| 310 | delete_cmd_entry(); |
| 311 | find_command(name, &entry, 1); |
| 312 | if (verbose) { |
| 313 | if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */ |
| 314 | cmdp = cmdlookup(name, 0); |
| 315 | printentry(cmdp); |
| 316 | } |
| 317 | flushall(); |
| 318 | } |
| 319 | argptr++; |
| 320 | } |
| 321 | return 0; |
| 322 | } |
| 323 | |
| 324 | |
| 325 | STATIC void |
| 326 | printentry(cmdp) |
| 327 | struct tblentry *cmdp; |
| 328 | { |
| 329 | int index; |
| 330 | char *path; |
| 331 | char *name; |
| 332 | |
| 333 | if (cmdp->cmdtype == CMDNORMAL) { |
| 334 | index = cmdp->param.index; |
| 335 | path = pathval(); |
| 336 | do { |
| 337 | name = padvance(&path, cmdp->cmdname); |
| 338 | stunalloc(name); |
| 339 | } while (--index >= 0); |
| 340 | out1str(name); |
| 341 | } else if (cmdp->cmdtype == CMDBUILTIN) { |
| 342 | out1fmt("builtin %s", cmdp->cmdname); |
| 343 | } else if (cmdp->cmdtype == CMDFUNCTION) { |
| 344 | out1fmt("function %s", cmdp->cmdname); |
| 345 | #ifdef DEBUG |
| 346 | } else { |
| 347 | error("internal error: cmdtype %d", cmdp->cmdtype); |
| 348 | #endif |
| 349 | } |
| 350 | if (cmdp->rehash) |
| 351 | out1c('*'); |
| 352 | out1c('\n'); |
| 353 | } |
| 354 | |
| 355 | |
| 356 | |
| 357 | /* |
| 358 | * Resolve a command name. If you change this routine, you may have to |
| 359 | * change the shellexec routine as well. |
| 360 | */ |
| 361 | |
| 362 | void |
| 363 | find_command(name, entry, printerr) |
| 364 | char *name; |
| 365 | struct cmdentry *entry; |
| 366 | { |
| 367 | struct tblentry *cmdp; |
| 368 | int index; |
| 369 | int prev; |
| 370 | char *path; |
| 371 | char *fullname; |
| 372 | struct stat statb; |
| 373 | int e; |
| 374 | int i; |
| 375 | |
| 376 | /* If name contains a slash, don't use the hash table */ |
| 377 | if (strchr(name, '/') != NULL) { |
| 378 | entry->cmdtype = CMDNORMAL; |
| 379 | entry->u.index = 0; |
| 380 | return; |
| 381 | } |
| 382 | |
| 383 | /* If name is in the table, and not invalidated by cd, we're done */ |
| 384 | if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) |
| 385 | goto success; |
| 386 | |
| 387 | /* If %builtin not in path, check for builtin next */ |
| 388 | if (builtinloc < 0 && (i = find_builtin(name)) >= 0) { |
| 389 | INTOFF; |
| 390 | cmdp = cmdlookup(name, 1); |
| 391 | cmdp->cmdtype = CMDBUILTIN; |
| 392 | cmdp->param.index = i; |
| 393 | INTON; |
| 394 | goto success; |
| 395 | } |
| 396 | |
| 397 | /* We have to search path. */ |
| 398 | prev = -1; /* where to start */ |
| 399 | if (cmdp) { /* doing a rehash */ |
| 400 | if (cmdp->cmdtype == CMDBUILTIN) |
| 401 | prev = builtinloc; |
| 402 | else |
| 403 | prev = cmdp->param.index; |
| 404 | } |
| 405 | |
| 406 | path = pathval(); |
| 407 | e = ENOENT; |
| 408 | index = -1; |
| 409 | loop: |
| 410 | while ((fullname = padvance(&path, name)) != NULL) { |
| 411 | stunalloc(fullname); |
| 412 | index++; |
| 413 | if (pathopt) { |
| 414 | if (prefix("builtin", pathopt)) { |
| 415 | if ((i = find_builtin(name)) < 0) |
| 416 | goto loop; |
| 417 | INTOFF; |
| 418 | cmdp = cmdlookup(name, 1); |
| 419 | cmdp->cmdtype = CMDBUILTIN; |
| 420 | cmdp->param.index = i; |
| 421 | INTON; |
| 422 | goto success; |
| 423 | } else if (prefix("func", pathopt)) { |
| 424 | /* handled below */ |
| 425 | } else { |
| 426 | goto loop; /* ignore unimplemented options */ |
| 427 | } |
| 428 | } |
| 429 | /* if rehash, don't redo absolute path names */ |
| 430 | if (fullname[0] == '/' && index <= prev) { |
| 431 | if (index < prev) |
| 432 | goto loop; |
| 433 | TRACE(("searchexec \"%s\": no change\n", name)); |
| 434 | goto success; |
| 435 | } |
| 436 | while (stat(fullname, &statb) < 0) { |
| 437 | #ifdef SYSV |
| 438 | if (errno == EINTR) |
| 439 | continue; |
| 440 | #endif |
| 441 | if (errno != ENOENT && errno != ENOTDIR) |
| 442 | e = errno; |
| 443 | goto loop; |
| 444 | } |
| 445 | e = EACCES; /* if we fail, this will be the error */ |
| 446 | if ((statb.st_mode & S_IFMT) != S_IFREG) |
| 447 | goto loop; |
| 448 | if (pathopt) { /* this is a %func directory */ |
| 449 | stalloc(strlen(fullname) + 1); |
| 450 | readcmdfile(fullname); |
| 451 | if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION) |
| 452 | error("%s not defined in %s", name, fullname); |
| 453 | stunalloc(fullname); |
| 454 | goto success; |
| 455 | } |
| 456 | if (statb.st_uid == geteuid()) { |
| 457 | if ((statb.st_mode & 0100) == 0) |
| 458 | goto loop; |
| 459 | } else if (statb.st_gid == getegid()) { |
| 460 | if ((statb.st_mode & 010) == 0) |
| 461 | goto loop; |
| 462 | } else { |
| 463 | if ((statb.st_mode & 01) == 0) |
| 464 | goto loop; |
| 465 | } |
| 466 | TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname)); |
| 467 | INTOFF; |
| 468 | cmdp = cmdlookup(name, 1); |
| 469 | cmdp->cmdtype = CMDNORMAL; |
| 470 | cmdp->param.index = index; |
| 471 | INTON; |
| 472 | goto success; |
| 473 | } |
| 474 | |
| 475 | /* We failed. If there was an entry for this command, delete it */ |
| 476 | if (cmdp) |
| 477 | delete_cmd_entry(); |
| 478 | if (printerr) |
| 479 | outfmt(out2, "%s: %s\n", name, errmsg(e, E_EXEC)); |
| 480 | entry->cmdtype = CMDUNKNOWN; |
| 481 | return; |
| 482 | |
| 483 | success: |
| 484 | cmdp->rehash = 0; |
| 485 | entry->cmdtype = cmdp->cmdtype; |
| 486 | entry->u = cmdp->param; |
| 487 | } |
| 488 | |
| 489 | |
| 490 | |
| 491 | /* |
| 492 | * Search the table of builtin commands. |
| 493 | */ |
| 494 | |
| 495 | int |
| 496 | find_builtin(name) |
| 497 | char *name; |
| 498 | { |
| 499 | const register struct builtincmd *bp; |
| 500 | |
| 501 | for (bp = builtincmd ; bp->name ; bp++) { |
| 502 | if (*bp->name == *name && equal(bp->name, name)) |
| 503 | return bp->code; |
| 504 | } |
| 505 | return -1; |
| 506 | } |
| 507 | |
| 508 | |
| 509 | |
| 510 | /* |
| 511 | * Called when a cd is done. Marks all commands so the next time they |
| 512 | * are executed they will be rehashed. |
| 513 | */ |
| 514 | |
| 515 | void |
| 516 | hashcd() { |
| 517 | struct tblentry **pp; |
| 518 | struct tblentry *cmdp; |
| 519 | |
| 520 | for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) { |
| 521 | for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { |
| 522 | if (cmdp->cmdtype == CMDNORMAL |
| 523 | || cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0) |
| 524 | cmdp->rehash = 1; |
| 525 | } |
| 526 | } |
| 527 | } |
| 528 | |
| 529 | |
| 530 | |
| 531 | /* |
| 532 | * Called before PATH is changed. The argument is the new value of PATH; |
| 533 | * pathval() still returns the old value at this point. Called with |
| 534 | * interrupts off. |
| 535 | */ |
| 536 | |
| 537 | void |
| 538 | changepath(newval) |
| 539 | char *newval; |
| 540 | { |
| 541 | char *old, *new; |
| 542 | int index; |
| 543 | int firstchange; |
| 544 | int bltin; |
| 545 | |
| 546 | old = pathval(); |
| 547 | new = newval; |
| 548 | firstchange = 9999; /* assume no change */ |
| 549 | index = 0; |
| 550 | bltin = -1; |
| 551 | for (;;) { |
| 552 | if (*old != *new) { |
| 553 | firstchange = index; |
| 554 | if (*old == '\0' && *new == ':' |
| 555 | || *old == ':' && *new == '\0') |
| 556 | firstchange++; |
| 557 | old = new; /* ignore subsequent differences */ |
| 558 | } |
| 559 | if (*new == '\0') |
| 560 | break; |
| 561 | if (*new == '%' && bltin < 0 && prefix("builtin", new + 1)) |
| 562 | bltin = index; |
| 563 | if (*new == ':') { |
| 564 | index++; |
| 565 | } |
| 566 | new++, old++; |
| 567 | } |
| 568 | if (builtinloc < 0 && bltin >= 0) |
| 569 | builtinloc = bltin; /* zap builtins */ |
| 570 | if (builtinloc >= 0 && bltin < 0) |
| 571 | firstchange = 0; |
| 572 | clearcmdentry(firstchange); |
| 573 | builtinloc = bltin; |
| 574 | } |
| 575 | |
| 576 | |
| 577 | /* |
| 578 | * Clear out command entries. The argument specifies the first entry in |
| 579 | * PATH which has changed. |
| 580 | */ |
| 581 | |
| 582 | STATIC void |
| 583 | clearcmdentry(firstchange) { |
| 584 | struct tblentry **tblp; |
| 585 | struct tblentry **pp; |
| 586 | struct tblentry *cmdp; |
| 587 | |
| 588 | INTOFF; |
| 589 | for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { |
| 590 | pp = tblp; |
| 591 | while ((cmdp = *pp) != NULL) { |
| 592 | if (cmdp->cmdtype == CMDNORMAL && cmdp->param.index >= firstchange |
| 593 | || cmdp->cmdtype == CMDBUILTIN && builtinloc >= firstchange) { |
| 594 | *pp = cmdp->next; |
| 595 | ckfree(cmdp); |
| 596 | } else { |
| 597 | pp = &cmdp->next; |
| 598 | } |
| 599 | } |
| 600 | } |
| 601 | INTON; |
| 602 | } |
| 603 | |
| 604 | |
| 605 | /* |
| 606 | * Delete all functions. |
| 607 | */ |
| 608 | |
| 609 | #ifdef mkinit |
| 610 | MKINIT void deletefuncs(); |
| 611 | |
| 612 | SHELLPROC { |
| 613 | deletefuncs(); |
| 614 | } |
| 615 | #endif |
| 616 | |
| 617 | void |
| 618 | deletefuncs() { |
| 619 | struct tblentry **tblp; |
| 620 | struct tblentry **pp; |
| 621 | struct tblentry *cmdp; |
| 622 | |
| 623 | INTOFF; |
| 624 | for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) { |
| 625 | pp = tblp; |
| 626 | while ((cmdp = *pp) != NULL) { |
| 627 | if (cmdp->cmdtype == CMDFUNCTION) { |
| 628 | *pp = cmdp->next; |
| 629 | freefunc(cmdp->param.func); |
| 630 | ckfree(cmdp); |
| 631 | } else { |
| 632 | pp = &cmdp->next; |
| 633 | } |
| 634 | } |
| 635 | } |
| 636 | INTON; |
| 637 | } |
| 638 | |
| 639 | |
| 640 | |
| 641 | /* |
| 642 | * Locate a command in the command hash table. If "add" is nonzero, |
| 643 | * add the command to the table if it is not already present. The |
| 644 | * variable "lastcmdentry" is set to point to the address of the link |
| 645 | * pointing to the entry, so that delete_cmd_entry can delete the |
| 646 | * entry. |
| 647 | */ |
| 648 | |
| 649 | struct tblentry **lastcmdentry; |
| 650 | |
| 651 | |
| 652 | STATIC struct tblentry * |
| 653 | cmdlookup(name, add) |
| 654 | char *name; |
| 655 | { |
| 656 | int hashval; |
| 657 | register char *p; |
| 658 | struct tblentry *cmdp; |
| 659 | struct tblentry **pp; |
| 660 | |
| 661 | p = name; |
| 662 | hashval = *p << 4; |
| 663 | while (*p) |
| 664 | hashval += *p++; |
| 665 | hashval &= 0x7FFF; |
| 666 | pp = &cmdtable[hashval % CMDTABLESIZE]; |
| 667 | for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) { |
| 668 | if (equal(cmdp->cmdname, name)) |
| 669 | break; |
| 670 | pp = &cmdp->next; |
| 671 | } |
| 672 | if (add && cmdp == NULL) { |
| 673 | INTOFF; |
| 674 | cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB |
| 675 | + strlen(name) + 1); |
| 676 | cmdp->next = NULL; |
| 677 | cmdp->cmdtype = CMDUNKNOWN; |
| 678 | cmdp->rehash = 0; |
| 679 | strcpy(cmdp->cmdname, name); |
| 680 | INTON; |
| 681 | } |
| 682 | lastcmdentry = pp; |
| 683 | return cmdp; |
| 684 | } |
| 685 | |
| 686 | |
| 687 | /* |
| 688 | * Delete the command entry returned on the last lookup. |
| 689 | */ |
| 690 | |
| 691 | STATIC void |
| 692 | delete_cmd_entry() { |
| 693 | struct tblentry *cmdp; |
| 694 | |
| 695 | INTOFF; |
| 696 | cmdp = *lastcmdentry; |
| 697 | *lastcmdentry = cmdp->next; |
| 698 | ckfree(cmdp); |
| 699 | INTON; |
| 700 | } |
| 701 | |
| 702 | |
| 703 | |
| 704 | #ifdef notdef |
| 705 | void |
| 706 | getcmdentry(name, entry) |
| 707 | char *name; |
| 708 | struct cmdentry *entry; |
| 709 | { |
| 710 | struct tblentry *cmdp = cmdlookup(name, 0); |
| 711 | |
| 712 | if (cmdp) { |
| 713 | entry->u = cmdp->param; |
| 714 | entry->cmdtype = cmdp->cmdtype; |
| 715 | } else { |
| 716 | entry->cmdtype = CMDUNKNOWN; |
| 717 | entry->u.index = 0; |
| 718 | } |
| 719 | } |
| 720 | #endif |
| 721 | |
| 722 | |
| 723 | /* |
| 724 | * Add a new command entry, replacing any existing command entry for |
| 725 | * the same name. |
| 726 | */ |
| 727 | |
| 728 | void |
| 729 | addcmdentry(name, entry) |
| 730 | char *name; |
| 731 | struct cmdentry *entry; |
| 732 | { |
| 733 | struct tblentry *cmdp; |
| 734 | |
| 735 | INTOFF; |
| 736 | cmdp = cmdlookup(name, 1); |
| 737 | if (cmdp->cmdtype == CMDFUNCTION) { |
| 738 | freefunc(cmdp->param.func); |
| 739 | } |
| 740 | cmdp->cmdtype = entry->cmdtype; |
| 741 | cmdp->param = entry->u; |
| 742 | INTON; |
| 743 | } |
| 744 | |
| 745 | |
| 746 | /* |
| 747 | * Define a shell function. |
| 748 | */ |
| 749 | |
| 750 | void |
| 751 | defun(name, func) |
| 752 | char *name; |
| 753 | union node *func; |
| 754 | { |
| 755 | struct cmdentry entry; |
| 756 | |
| 757 | INTOFF; |
| 758 | entry.cmdtype = CMDFUNCTION; |
| 759 | entry.u.func = copyfunc(func); |
| 760 | addcmdentry(name, &entry); |
| 761 | INTON; |
| 762 | } |
| 763 | |
| 764 | |
| 765 | /* |
| 766 | * Delete a function if it exists. |
| 767 | */ |
| 768 | |
| 769 | void |
| 770 | unsetfunc(name) |
| 771 | char *name; |
| 772 | { |
| 773 | struct tblentry *cmdp; |
| 774 | |
| 775 | if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) { |
| 776 | freefunc(cmdp->param.func); |
| 777 | delete_cmd_entry(); |
| 778 | } |
| 779 | } |