2 * Copyright (c) 1991, 1993
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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 1.7 2006/06/19 12:06:07 corecode 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, const 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(const char **path, const char *name)
188 for (p = start ; *p && *p != ':' && *p != '%' ; p++);
189 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
190 while (stackblocksize() < len)
194 memcpy(q, start, p - start);
202 while (*p && *p != ':') p++;
213 /*** Command hashing code ***/
217 hashcmd(int argc __unused, char **argv __unused)
219 struct tblentry **pp;
220 struct tblentry *cmdp;
223 struct cmdentry entry;
227 while ((c = nextopt("rv")) != '\0') {
230 } else if (c == 'v') {
234 if (*argptr == NULL) {
235 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
236 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
237 if (cmdp->cmdtype == CMDNORMAL)
238 printentry(cmdp, verbose);
243 while ((name = *argptr) != NULL) {
244 if ((cmdp = cmdlookup(name, 0)) != NULL
245 && (cmdp->cmdtype == CMDNORMAL
246 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0)))
248 find_command(name, &entry, 1, pathval());
250 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */
251 cmdp = cmdlookup(name, 0);
253 printentry(cmdp, verbose);
255 outfmt(&errout, "%s: not found\n", name);
266 printentry(struct tblentry *cmdp, int verbose)
272 if (cmdp->cmdtype == CMDNORMAL) {
273 index = cmdp->param.index;
276 name = padvance(&path, cmdp->cmdname);
278 } while (--index >= 0);
280 } else if (cmdp->cmdtype == CMDBUILTIN) {
281 out1fmt("builtin %s", cmdp->cmdname);
282 } else if (cmdp->cmdtype == CMDFUNCTION) {
283 out1fmt("function %s", cmdp->cmdname);
286 name = commandtext(cmdp->param.func);
294 error("internal error: cmdtype %d", cmdp->cmdtype);
305 * Resolve a command name. If you change this routine, you may have to
306 * change the shellexec routine as well.
310 find_command(char *name, struct cmdentry *entry, int printerr, const char *path)
312 struct tblentry *cmdp;
320 /* If name contains a slash, don't use the hash table */
321 if (strchr(name, '/') != NULL) {
322 entry->cmdtype = CMDNORMAL;
327 /* If name is in the table, and not invalidated by cd, we're done */
328 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0)
331 /* If %builtin not in path, check for builtin next */
332 if (builtinloc < 0 && (i = find_builtin(name)) >= 0) {
334 cmdp = cmdlookup(name, 1);
335 cmdp->cmdtype = CMDBUILTIN;
336 cmdp->param.index = i;
341 /* We have to search path. */
342 prev = -1; /* where to start */
343 if (cmdp) { /* doing a rehash */
344 if (cmdp->cmdtype == CMDBUILTIN)
347 prev = cmdp->param.index;
353 while ((fullname = padvance(&path, name)) != NULL) {
357 if (prefix("builtin", pathopt)) {
358 if ((i = find_builtin(name)) < 0)
361 cmdp = cmdlookup(name, 1);
362 cmdp->cmdtype = CMDBUILTIN;
363 cmdp->param.index = i;
366 } else if (prefix("func", pathopt)) {
369 goto loop; /* ignore unimplemented options */
372 /* if rehash, don't redo absolute path names */
373 if (fullname[0] == '/' && index <= prev) {
376 TRACE(("searchexec \"%s\": no change\n", name));
379 if (stat(fullname, &statb) < 0) {
380 if (errno != ENOENT && errno != ENOTDIR)
384 e = EACCES; /* if we fail, this will be the error */
385 if (!S_ISREG(statb.st_mode))
387 if (pathopt) { /* this is a %func directory */
388 stalloc(strlen(fullname) + 1);
389 readcmdfile(fullname);
390 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
391 error("%s not defined in %s", name, fullname);
396 if (statb.st_uid == geteuid()) {
397 if ((statb.st_mode & 0100) == 0)
399 } else if (statb.st_gid == getegid()) {
400 if ((statb.st_mode & 010) == 0)
403 if ((statb.st_mode & 01) == 0)
407 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
409 cmdp = cmdlookup(name, 1);
410 cmdp->cmdtype = CMDNORMAL;
411 cmdp->param.index = index;
416 /* We failed. If there was an entry for this command, delete it */
420 outfmt(out2, "%s: %s\n", name, errmsg(e, E_EXEC));
421 entry->cmdtype = CMDUNKNOWN;
427 entry->cmdtype = cmdp->cmdtype;
428 entry->u = cmdp->param;
430 entry->cmdtype = CMDUNKNOWN;
436 * Search the table of builtin commands.
440 find_builtin(char *name)
442 const struct builtincmd *bp;
444 for (bp = builtincmd ; bp->name ; bp++) {
445 if (*bp->name == *name && equal(bp->name, name))
454 * Called when a cd is done. Marks all commands so the next time they
455 * are executed they will be rehashed.
461 struct tblentry **pp;
462 struct tblentry *cmdp;
464 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
465 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
466 if (cmdp->cmdtype == CMDNORMAL
467 || (cmdp->cmdtype == CMDBUILTIN && builtinloc >= 0))
476 * Called before PATH is changed. The argument is the new value of PATH;
477 * pathval() still returns the old value at this point. Called with
482 changepath(const char *newval)
484 const char *old, *new;
491 firstchange = 9999; /* assume no change */
497 if ((*old == '\0' && *new == ':')
498 || (*old == ':' && *new == '\0'))
500 old = new; /* ignore subsequent differences */
504 if (*new == '%' && bltin < 0 && prefix("builtin", new + 1))
511 if (builtinloc < 0 && bltin >= 0)
512 builtinloc = bltin; /* zap builtins */
513 if (builtinloc >= 0 && bltin < 0)
515 clearcmdentry(firstchange);
521 * Clear out command entries. The argument specifies the first entry in
522 * PATH which has changed.
526 clearcmdentry(int firstchange)
528 struct tblentry **tblp;
529 struct tblentry **pp;
530 struct tblentry *cmdp;
533 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
535 while ((cmdp = *pp) != NULL) {
536 if ((cmdp->cmdtype == CMDNORMAL &&
537 cmdp->param.index >= firstchange)
538 || (cmdp->cmdtype == CMDBUILTIN &&
539 builtinloc >= firstchange)) {
552 * Delete all functions.
556 MKINIT void deletefuncs(void);
566 struct tblentry **tblp;
567 struct tblentry **pp;
568 struct tblentry *cmdp;
571 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
573 while ((cmdp = *pp) != NULL) {
574 if (cmdp->cmdtype == CMDFUNCTION) {
576 freefunc(cmdp->param.func);
589 * Locate a command in the command hash table. If "add" is nonzero,
590 * add the command to the table if it is not already present. The
591 * variable "lastcmdentry" is set to point to the address of the link
592 * pointing to the entry, so that delete_cmd_entry can delete the
596 STATIC struct tblentry **lastcmdentry;
599 STATIC struct tblentry *
600 cmdlookup(char *name, int add)
604 struct tblentry *cmdp;
605 struct tblentry **pp;
612 pp = &cmdtable[hashval % CMDTABLESIZE];
613 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
614 if (equal(cmdp->cmdname, name))
618 if (add && cmdp == NULL) {
620 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
623 cmdp->cmdtype = CMDUNKNOWN;
625 strcpy(cmdp->cmdname, name);
633 * Delete the command entry returned on the last lookup.
637 delete_cmd_entry(void)
639 struct tblentry *cmdp;
642 cmdp = *lastcmdentry;
643 *lastcmdentry = cmdp->next;
651 * Add a new command entry, replacing any existing command entry for
656 addcmdentry(char *name, struct cmdentry *entry)
658 struct tblentry *cmdp;
661 cmdp = cmdlookup(name, 1);
662 if (cmdp->cmdtype == CMDFUNCTION) {
663 freefunc(cmdp->param.func);
665 cmdp->cmdtype = entry->cmdtype;
666 cmdp->param = entry->u;
672 * Define a shell function.
676 defun(char *name, union node *func)
678 struct cmdentry entry;
681 entry.cmdtype = CMDFUNCTION;
682 entry.u.func = copyfunc(func);
683 addcmdentry(name, &entry);
689 * Delete a function if it exists.
693 unsetfunc(char *name)
695 struct tblentry *cmdp;
697 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
698 freefunc(cmdp->param.func);
705 * Locate and print what a word is...
709 typecmd(int argc, char **argv)
711 struct cmdentry entry;
712 struct tblentry *cmdp;
713 const char * const *pp;
717 extern const char *const parsekwd[];
719 for (i = 1; i < argc; i++) {
721 /* First look at the keywords */
722 for (pp = parsekwd; *pp; pp++)
723 if (**pp == *argv[i] && equal(*pp, argv[i]))
727 out1str(" is a shell keyword\n");
731 /* Then look at the aliases */
732 if ((ap = lookupalias(argv[i], 1)) != NULL) {
733 out1fmt(" is an alias for %s\n", ap->val);
737 /* Then check if it is a tracked alias */
738 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
739 entry.cmdtype = cmdp->cmdtype;
740 entry.u = cmdp->param;
743 /* Finally use brute force */
744 find_command(argv[i], &entry, 0, pathval());
747 switch (entry.cmdtype) {
749 if (strchr(argv[i], '/') == NULL) {
750 const char *path = pathval();
752 int j = entry.u.index;
754 name = padvance(&path, argv[i]);
757 out1fmt(" is%s %s\n",
758 cmdp ? " a tracked alias for" : "", name);
760 if (access(argv[i], X_OK) == 0) {
761 out1fmt(" is %s\n", argv[i]);
764 out1fmt(": %s\n", strerror(errno));
771 out1str(" is a shell function\n");
775 out1str(" is a shell builtin\n");
779 out1str(": not found\n");