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36 * @(#)exec.c 8.4 (Berkeley) 6/8/95
37 * $FreeBSD: src/bin/sh/exec.c,v 1.14.2.4 2002/08/27 01:36:28 tjr Exp $
38 * $DragonFly: src/bin/sh/exec.c,v 1.3 2003/08/24 16:26:00 drhodus Exp $
41 #include <sys/types.h>
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
53 * We should investigate converting to a linear search, even though that
54 * would make the command name "hash" a misnomer.
79 #define CMDTABLESIZE 31 /* should be prime */
80 #define ARB 1 /* actual size determined at run time */
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 */
93 STATIC struct tblentry *cmdtable[CMDTABLESIZE];
94 STATIC int builtinloc = -1; /* index in path of %builtin, or -1 */
95 int exerrno = 0; /* Last exec error */
98 STATIC void tryexec(char *, char **, char **);
99 STATIC void printentry(struct tblentry *, int);
100 STATIC struct tblentry *cmdlookup(char *, int);
101 STATIC void delete_cmd_entry(void);
106 * Exec a program. Never returns. If you change this routine, you may
107 * have to change the find_command routine as well.
111 shellexec(char **argv, char **envp, char *path, int index)
116 if (strchr(argv[0], '/') != NULL) {
117 tryexec(argv[0], argv, envp);
121 while ((cmdname = padvance(&path, argv[0])) != NULL) {
122 if (--index < 0 && pathopt == NULL) {
123 tryexec(cmdname, argv, envp);
124 if (errno != ENOENT && errno != ENOTDIR)
131 /* Map to POSIX errors */
143 exerror(EXEXEC, "%s: %s", argv[0], errmsg(e, E_EXEC));
148 tryexec(char *cmd, char **argv, char **envp)
152 execve(cmd, argv, envp);
156 setinputfile(cmd, 0);
157 commandname = arg0 = savestr(argv[0]);
159 exraise(EXSHELLPROC);
166 * Do a path search. The variable path (passed by reference) should be
167 * set to the start of the path before the first call; padvance will update
168 * this value as it proceeds. Successive calls to padvance will return
169 * the possible path expansions in sequence. If an option (indicated by
170 * a percent sign) appears in the path entry then the global variable
171 * pathopt will be set to point to it; otherwise pathopt will be set to
178 padvance(char **path, char *name)
187 for (p = start ; *p && *p != ':' && *p != '%' ; p++);
188 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
189 while (stackblocksize() < len)
193 memcpy(q, start, p - start);
201 while (*p && *p != ':') p++;
212 /*** Command hashing code ***/
216 hashcmd(int argc __unused, char **argv __unused)
218 struct tblentry **pp;
219 struct tblentry *cmdp;
222 struct cmdentry entry;
226 while ((c = nextopt("rv")) != '\0') {
229 } else if (c == 'v') {
233 if (*argptr == NULL) {
234 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
235 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
236 if (cmdp->cmdtype == CMDNORMAL)
237 printentry(cmdp, verbose);
242 while ((name = *argptr) != NULL) {
243 if ((cmdp = cmdlookup(name, 0)) != NULL
244 && (cmdp->cmdtype == CMDNORMAL
245 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)))
247 find_command(name, &entry, 1, pathval());
249 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */
250 cmdp = cmdlookup(name, 0);
252 printentry(cmdp, verbose);
254 outfmt(&errout, "%s: not found\n", name);
265 printentry(struct tblentry *cmdp, int verbose)
271 if (cmdp->cmdtype == CMDNORMAL) {
272 index = cmdp->param.index;
275 name = padvance(&path, cmdp->cmdname);
277 } while (--index >= 0);
279 } else if (cmdp->cmdtype == CMDBUILTIN) {
280 out1fmt("builtin %s", cmdp->cmdname);
281 } else if (cmdp->cmdtype == CMDFUNCTION) {
282 out1fmt("function %s", cmdp->cmdname);
285 name = commandtext(cmdp->param.func);
293 error("internal error: cmdtype %d", cmdp->cmdtype);
304 * Resolve a command name. If you change this routine, you may have to
305 * change the shellexec routine as well.
309 find_command(char *name, struct cmdentry *entry, int printerr, char *path)
311 struct tblentry *cmdp;
319 /* If name contains a slash, don't use the hash table */
320 if (strchr(name, '/') != NULL) {
321 entry->cmdtype = CMDNORMAL;
326 /* If name is in the table, and not invalidated by cd, we're done */
327 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0)
330 /* If %builtin not in path, check for builtin next */
331 if (builtinloc < 0 && (i = find_builtin(name)) >= 0) {
333 cmdp = cmdlookup(name, 1);
334 cmdp->cmdtype = CMDBUILTIN;
335 cmdp->param.index = i;
340 /* We have to search path. */
341 prev = -1; /* where to start */
342 if (cmdp) { /* doing a rehash */
343 if (cmdp->cmdtype == CMDBUILTIN)
346 prev = cmdp->param.index;
352 while ((fullname = padvance(&path, name)) != NULL) {
356 if (prefix("builtin", pathopt)) {
357 if ((i = find_builtin(name)) < 0)
360 cmdp = cmdlookup(name, 1);
361 cmdp->cmdtype = CMDBUILTIN;
362 cmdp->param.index = i;
365 } else if (prefix("func", pathopt)) {
368 goto loop; /* ignore unimplemented options */
371 /* if rehash, don't redo absolute path names */
372 if (fullname[0] == '/' && index <= prev) {
375 TRACE(("searchexec \"%s\": no change\n", name));
378 if (stat(fullname, &statb) < 0) {
379 if (errno != ENOENT && errno != ENOTDIR)
383 e = EACCES; /* if we fail, this will be the error */
384 if (!S_ISREG(statb.st_mode))
386 if (pathopt) { /* this is a %func directory */
387 stalloc(strlen(fullname) + 1);
388 readcmdfile(fullname);
389 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
390 error("%s not defined in %s", name, fullname);
395 if (statb.st_uid == geteuid()) {
396 if ((statb.st_mode & 0100) == 0)
398 } else if (statb.st_gid == getegid()) {
399 if ((statb.st_mode & 010) == 0)
402 if ((statb.st_mode & 01) == 0)
406 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
408 cmdp = cmdlookup(name, 1);
409 cmdp->cmdtype = CMDNORMAL;
410 cmdp->param.index = index;
415 /* We failed. If there was an entry for this command, delete it */
419 outfmt(out2, "%s: %s\n", name, errmsg(e, E_EXEC));
420 entry->cmdtype = CMDUNKNOWN;
425 entry->cmdtype = cmdp->cmdtype;
426 entry->u = cmdp->param;
432 * Search the table of builtin commands.
436 find_builtin(char *name)
438 const struct builtincmd *bp;
440 for (bp = builtincmd ; bp->name ; bp++) {
441 if (*bp->name == *name && equal(bp->name, name))
450 * Called when a cd is done. Marks all commands so the next time they
451 * are executed they will be rehashed.
457 struct tblentry **pp;
458 struct tblentry *cmdp;
460 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
461 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
462 if (cmdp->cmdtype == CMDNORMAL
463 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))
472 * Called before PATH is changed. The argument is the new value of PATH;
473 * pathval() still returns the old value at this point. Called with
478 changepath(const char *newval)
480 const char *old, *new;
487 firstchange = 9999; /* assume no change */
493 if ((*old == '\0' && *new == ':')
494 || (*old == ':' && *new == '\0'))
496 old = new; /* ignore subsequent differences */
500 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1))
507 if (builtinloc < 0 && bltin >= 0)
508 builtinloc = bltin; /* zap builtins */
509 if (builtinloc >= 0 && bltin < 0)
511 clearcmdentry(firstchange);
517 * Clear out command entries. The argument specifies the first entry in
518 * PATH which has changed.
522 clearcmdentry(int firstchange)
524 struct tblentry **tblp;
525 struct tblentry **pp;
526 struct tblentry *cmdp;
529 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
531 while ((cmdp = *pp) != NULL) {
532 if ((cmdp->cmdtype == CMDNORMAL &&
533 cmdp->param.index >= firstchange)
534 || (cmdp->cmdtype == CMDBUILTIN &&
535 builtinloc >= firstchange)) {
548 * Delete all functions.
552 MKINIT void deletefuncs();
562 struct tblentry **tblp;
563 struct tblentry **pp;
564 struct tblentry *cmdp;
567 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
569 while ((cmdp = *pp) != NULL) {
570 if (cmdp->cmdtype == CMDFUNCTION) {
572 freefunc(cmdp->param.func);
585 * Locate a command in the command hash table. If "add" is nonzero,
586 * add the command to the table if it is not already present. The
587 * variable "lastcmdentry" is set to point to the address of the link
588 * pointing to the entry, so that delete_cmd_entry can delete the
592 STATIC struct tblentry **lastcmdentry;
595 STATIC struct tblentry *
596 cmdlookup(char *name, int add)
600 struct tblentry *cmdp;
601 struct tblentry **pp;
608 pp = &cmdtable[hashval % CMDTABLESIZE];
609 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
610 if (equal(cmdp->cmdname, name))
614 if (add && cmdp == NULL) {
616 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
619 cmdp->cmdtype = CMDUNKNOWN;
621 strcpy(cmdp->cmdname, name);
629 * Delete the command entry returned on the last lookup.
633 delete_cmd_entry(void)
635 struct tblentry *cmdp;
638 cmdp = *lastcmdentry;
639 *lastcmdentry = cmdp->next;
647 * Add a new command entry, replacing any existing command entry for
652 addcmdentry(char *name, struct cmdentry *entry)
654 struct tblentry *cmdp;
657 cmdp = cmdlookup(name, 1);
658 if (cmdp->cmdtype == CMDFUNCTION) {
659 freefunc(cmdp->param.func);
661 cmdp->cmdtype = entry->cmdtype;
662 cmdp->param = entry->u;
668 * Define a shell function.
672 defun(char *name, union node *func)
674 struct cmdentry entry;
677 entry.cmdtype = CMDFUNCTION;
678 entry.u.func = copyfunc(func);
679 addcmdentry(name, &entry);
685 * Delete a function if it exists.
689 unsetfunc(char *name)
691 struct tblentry *cmdp;
693 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
694 freefunc(cmdp->param.func);
702 * Locate and print what a word is...
706 typecmd(int argc, char **argv)
708 struct cmdentry entry;
709 struct tblentry *cmdp;
714 extern char *const parsekwd[];
716 for (i = 1; i < argc; i++) {
718 /* First look at the keywords */
719 for (pp = (char **)parsekwd; *pp; pp++)
720 if (**pp == *argv[i] && equal(*pp, argv[i]))
724 out1str(" is a shell keyword\n");
728 /* Then look at the aliases */
729 if ((ap = lookupalias(argv[i], 1)) != NULL) {
730 out1fmt(" is an alias for %s\n", ap->val);
734 /* Then check if it is a tracked alias */
735 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
736 entry.cmdtype = cmdp->cmdtype;
737 entry.u = cmdp->param;
740 /* Finally use brute force */
741 find_command(argv[i], &entry, 0, pathval());
744 switch (entry.cmdtype) {
746 if (strchr(argv[i], '/') == NULL) {
747 char *path = pathval(), *name;
748 int j = entry.u.index;
750 name = padvance(&path, argv[i]);
753 out1fmt(" is%s %s\n",
754 cmdp ? " a tracked alias for" : "", name);
756 if (access(argv[i], X_OK) == 0)
757 out1fmt(" is %s\n", argv[i]);
759 out1fmt(": %s\n", strerror(errno));
764 out1str(" is a shell function\n");
768 out1str(" is a shell builtin\n");
772 out1str(": not found\n");