2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
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35 static char sccsid[] = "@(#)exec.c 8.4 (Berkeley) 6/8/95";
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include <sys/types.h>
50 * When commands are first encountered, they are entered in a hash table.
51 * This ensures that a full path search will not have to be done for them
54 * We should investigate converting to a linear search, even though that
55 * would make the command name "hash" a misnomer.
79 #define CMDTABLESIZE 31 /* should be prime */
84 struct tblentry *next; /* next entry in hash chain */
85 union param param; /* definition of builtin function */
86 int special; /* flag for special builtin commands */
87 signed char cmdtype; /* index identifying command */
88 char cmdname[]; /* name of command */
92 static struct tblentry *cmdtable[CMDTABLESIZE];
93 static int cmdtable_cd = 0; /* cmdtable contains cd-dependent entries */
94 int exerrno = 0; /* Last exec error */
97 static void tryexec(char *, char **, char **);
98 static void printentry(struct tblentry *, int);
99 static struct tblentry *cmdlookup(const char *, int);
100 static void delete_cmd_entry(void);
101 static void addcmdentry(const char *, struct cmdentry *);
106 * Exec a program. Never returns. If you change this routine, you may
107 * have to change the find_command routine as well.
109 * The argv array may be changed and element argv[-1] should be writable.
113 shellexec(char **argv, char **envp, const char *path, int idx)
119 if (strchr(argv[0], '/') != NULL) {
120 tryexec(argv[0], argv, envp);
124 while ((cmdname = padvance(&path, &opt, argv[0])) != NULL) {
125 if (--idx < 0 && opt == NULL) {
126 tryexec(cmdname, argv, envp);
127 if (errno != ENOENT && errno != ENOTDIR)
136 /* Map to POSIX errors */
137 if (e == ENOENT || e == ENOTDIR) {
139 exerror(EXEXEC, "%s: not found", argv[0]);
142 exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
148 tryexec(char *cmd, char **argv, char **envp)
154 execve(cmd, argv, envp);
158 in = open(cmd, O_RDONLY | O_NONBLOCK);
160 n = pread(in, buf, sizeof buf, 0);
162 if (n > 0 && memchr(buf, '\0', n) != NULL) {
168 *--argv = __DECONST(char *, _PATH_BSHELL);
169 execve(_PATH_BSHELL, argv, envp);
175 * Do a path search. The variable path (passed by reference) should be
176 * set to the start of the path before the first call; padvance will update
177 * this value as it proceeds. Successive calls to padvance will return
178 * the possible path expansions in sequence. If popt is not NULL, options
179 * are processed: if an option (indicated by a percent sign) appears in
180 * the path entry then *popt will be set to point to it; else *popt will be
181 * set to NULL. If popt is NULL, percent signs are not special.
185 padvance(const char **path, const char **popt, const char *name)
187 const char *p, *start;
195 for (p = start; *p && *p != ':' && *p != '%'; p++)
198 for (p = start; *p && *p != ':'; p++)
200 namelen = strlen(name);
201 len = p - start + namelen + 2; /* "2" is for '/' and '\0' */
203 CHECKSTRSPACE(len, q);
205 memcpy(q, start, p - start);
209 memcpy(q, name, namelen + 1);
213 while (*p && *p != ':') p++;
226 /*** Command hashing code ***/
230 hashcmd(int argc __unused, char **argv __unused)
232 struct tblentry **pp;
233 struct tblentry *cmdp;
236 struct cmdentry entry;
242 while ((c = nextopt("rv")) != '\0') {
245 } else if (c == 'v') {
249 if (*argptr == NULL) {
250 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
251 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
252 if (cmdp->cmdtype == CMDNORMAL)
253 printentry(cmdp, verbose);
258 while ((name = *argptr) != NULL) {
259 if ((cmdp = cmdlookup(name, 0)) != NULL
260 && cmdp->cmdtype == CMDNORMAL)
262 find_command(name, &entry, DO_ERR, pathval());
263 if (entry.cmdtype == CMDUNKNOWN)
266 cmdp = cmdlookup(name, 0);
268 printentry(cmdp, verbose);
270 outfmt(out2, "%s: not found\n", name);
282 printentry(struct tblentry *cmdp, int verbose)
285 const char *path, *opt;
288 if (cmdp->cmdtype == CMDNORMAL) {
289 idx = cmdp->param.index;
292 name = padvance(&path, &opt, cmdp->cmdname);
294 } while (--idx >= 0);
296 } else if (cmdp->cmdtype == CMDBUILTIN) {
297 out1fmt("builtin %s", cmdp->cmdname);
298 } else if (cmdp->cmdtype == CMDFUNCTION) {
299 out1fmt("function %s", cmdp->cmdname);
302 name = commandtext(getfuncnode(cmdp->param.func));
310 error("internal error: cmdtype %d", cmdp->cmdtype);
319 * Resolve a command name. If you change this routine, you may have to
320 * change the shellexec routine as well.
324 find_command(const char *name, struct cmdentry *entry, int act,
327 struct tblentry *cmdp, loc_cmd;
337 /* If name contains a slash, don't use the hash table */
338 if (strchr(name, '/') != NULL) {
339 entry->cmdtype = CMDNORMAL;
347 /* If name is in the table, we're done */
348 if ((cmdp = cmdlookup(name, 0)) != NULL) {
349 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
355 /* Check for builtin next */
356 if ((i = find_builtin(name, &spec)) >= 0) {
358 cmdp = cmdlookup(name, 1);
359 if (cmdp->cmdtype == CMDFUNCTION)
361 cmdp->cmdtype = CMDBUILTIN;
362 cmdp->param.index = i;
363 cmdp->special = spec;
368 /* We have to search path. */
372 for (;(fullname = padvance(&path, &opt, name)) != NULL;
373 stunalloc(fullname)) {
376 if (strncmp(opt, "func", 4) == 0) {
379 continue; /* ignore unimplemented options */
382 if (fullname[0] != '/')
384 if (stat(fullname, &statb) < 0) {
385 if (errno != ENOENT && errno != ENOTDIR)
389 e = EACCES; /* if we fail, this will be the error */
390 if (!S_ISREG(statb.st_mode))
392 if (opt) { /* this is a %func directory */
393 readcmdfile(fullname);
394 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
395 error("%s not defined in %s", name, fullname);
400 if (statb.st_uid == geteuid()) {
401 if ((statb.st_mode & 0100) == 0)
403 } else if (statb.st_gid == getegid()) {
404 if ((statb.st_mode & 010) == 0)
407 if ((statb.st_mode & 01) == 0)
411 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
414 cmdp = cmdlookup(name, 1);
415 if (cmdp->cmdtype == CMDFUNCTION)
417 cmdp->cmdtype = CMDNORMAL;
418 cmdp->param.index = idx;
425 if (e == ENOENT || e == ENOTDIR)
426 outfmt(out2, "%s: not found\n", name);
428 outfmt(out2, "%s: %s\n", name, strerror(e));
430 entry->cmdtype = CMDUNKNOWN;
438 entry->cmdtype = cmdp->cmdtype;
439 entry->u = cmdp->param;
440 entry->special = cmdp->special;
446 * Search the table of builtin commands.
450 find_builtin(const char *name, int *special)
452 const unsigned char *bp;
456 for (bp = builtincmd ; *bp ; bp += 2 + bp[0]) {
457 if (bp[0] == len && memcmp(bp + 2, name, len) == 0) {
458 *special = (bp[1] & BUILTIN_SPECIAL) != 0;
459 return bp[1] & ~BUILTIN_SPECIAL;
468 * Called when a cd is done. If any entry in cmdtable depends on the current
469 * directory, simply clear cmdtable completely.
482 * Called before PATH is changed. The argument is the new value of PATH;
483 * pathval() still returns the old value at this point. Called with
488 changepath(const char *newval __unused)
495 * Clear out cached utility locations.
501 struct tblentry **tblp;
502 struct tblentry **pp;
503 struct tblentry *cmdp;
506 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
508 while ((cmdp = *pp) != NULL) {
509 if (cmdp->cmdtype == CMDNORMAL) {
523 * Locate a command in the command hash table. If "add" is nonzero,
524 * add the command to the table if it is not already present. The
525 * variable "lastcmdentry" is set to point to the address of the link
526 * pointing to the entry, so that delete_cmd_entry can delete the
530 static struct tblentry **lastcmdentry;
533 static struct tblentry *
534 cmdlookup(const char *name, int add)
536 unsigned int hashval;
538 struct tblentry *cmdp;
539 struct tblentry **pp;
543 hashval = (unsigned char)*p << 4;
546 pp = &cmdtable[hashval % CMDTABLESIZE];
547 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
548 if (equal(cmdp->cmdname, name))
552 if (add && cmdp == NULL) {
555 cmdp = *pp = ckmalloc(sizeof (struct tblentry) + len + 1);
557 cmdp->cmdtype = CMDUNKNOWN;
558 memcpy(cmdp->cmdname, name, len + 1);
566 * Delete the command entry returned on the last lookup.
570 delete_cmd_entry(void)
572 struct tblentry *cmdp;
575 cmdp = *lastcmdentry;
576 *lastcmdentry = cmdp->next;
584 * Add a new command entry, replacing any existing command entry for
589 addcmdentry(const char *name, struct cmdentry *entry)
591 struct tblentry *cmdp;
594 cmdp = cmdlookup(name, 1);
595 if (cmdp->cmdtype == CMDFUNCTION) {
596 unreffunc(cmdp->param.func);
598 cmdp->cmdtype = entry->cmdtype;
599 cmdp->param = entry->u;
600 cmdp->special = entry->special;
606 * Define a shell function.
610 defun(const char *name, union node *func)
612 struct cmdentry entry;
615 entry.cmdtype = CMDFUNCTION;
616 entry.u.func = copyfunc(func);
618 addcmdentry(name, &entry);
624 * Delete a function if it exists.
625 * Called with interrupts off.
629 unsetfunc(const char *name)
631 struct tblentry *cmdp;
633 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
634 unreffunc(cmdp->param.func);
643 * Check if a function by a certain name exists.
646 isfunc(const char *name)
648 struct tblentry *cmdp;
649 cmdp = cmdlookup(name, 0);
650 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION);
655 * Shared code for the following builtin commands:
656 * type, command -v, command -V
660 typecmd_impl(int argc, char **argv, int cmd, const char *path)
662 struct cmdentry entry;
663 struct tblentry *cmdp;
664 const char *const *pp;
669 if (path != pathval())
672 for (i = 1; i < argc; i++) {
673 /* First look at the keywords */
674 for (pp = parsekwd; *pp; pp++)
675 if (**pp == *argv[i] && equal(*pp, argv[i]))
679 if (cmd == TYPECMD_SMALLV)
680 out1fmt("%s\n", argv[i]);
682 out1fmt("%s is a shell keyword\n", argv[i]);
686 /* Then look at the aliases */
687 if ((ap = lookupalias(argv[i], 1)) != NULL) {
688 if (cmd == TYPECMD_SMALLV) {
689 out1fmt("alias %s=", argv[i]);
691 outcslow('\n', out1);
693 out1fmt("%s is an alias for %s\n", argv[i],
698 /* Then check if it is a tracked alias */
699 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
700 entry.cmdtype = cmdp->cmdtype;
701 entry.u = cmdp->param;
702 entry.special = cmdp->special;
705 /* Finally use brute force */
706 find_command(argv[i], &entry, 0, path);
709 switch (entry.cmdtype) {
711 if (strchr(argv[i], '/') == NULL) {
712 const char *path2 = path;
715 int j = entry.u.index;
717 name = padvance(&path2, &opt2, argv[i]);
720 if (cmd == TYPECMD_SMALLV)
721 out1fmt("%s\n", name);
723 out1fmt("%s is%s %s\n", argv[i],
724 (cmdp && cmd == TYPECMD_TYPE) ?
725 " a tracked alias for" : "",
728 if (eaccess(argv[i], X_OK) == 0) {
729 if (cmd == TYPECMD_SMALLV)
730 out1fmt("%s\n", argv[i]);
732 out1fmt("%s is %s\n", argv[i],
735 if (cmd != TYPECMD_SMALLV)
736 outfmt(out2, "%s: %s\n",
737 argv[i], strerror(errno));
744 if (cmd == TYPECMD_SMALLV)
745 out1fmt("%s\n", argv[i]);
747 out1fmt("%s is a shell function\n", argv[i]);
751 if (cmd == TYPECMD_SMALLV)
752 out1fmt("%s\n", argv[i]);
753 else if (entry.special)
754 out1fmt("%s is a special shell builtin\n",
757 out1fmt("%s is a shell builtin\n", argv[i]);
761 if (cmd != TYPECMD_SMALLV)
762 outfmt(out2, "%s: not found\n", argv[i]);
768 if (path != pathval())
775 * Locate and print what a word is...
779 typecmd(int argc, char **argv)
781 if (argc > 2 && strcmp(argv[1], "--") == 0)
783 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));