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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9 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
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17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
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20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
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32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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");