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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36 * @(#)exec.c 8.4 (Berkeley) 6/8/95
37 * $FreeBSD: src/bin/sh/exec.c,v 1.52 2011/02/05 14:08:51 jilles Exp $
40 #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 int special; /* flag for special builtin commands */
88 short cmdtype; /* index identifying command */
89 char rehash; /* if set, cd done since entry created */
90 char cmdname[ARB]; /* name of command */
94 static struct tblentry *cmdtable[CMDTABLESIZE];
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(const char *, int);
101 static void delete_cmd_entry(void);
104 * Exec a program. Never returns. If you change this routine, you may
105 * have to change the find_command routine as well.
107 * The argv array may be changed and element argv[-1] should be writable.
111 shellexec(char **argv, char **envp, const char *path, int idx)
116 if (strchr(argv[0], '/') != NULL) {
117 tryexec(argv[0], argv, envp);
121 while ((cmdname = padvance(&path, argv[0])) != NULL) {
122 if (--idx < 0 && pathopt == NULL) {
123 tryexec(cmdname, argv, envp);
124 if (errno != ENOENT && errno != ENOTDIR)
133 /* Map to POSIX errors */
134 if (e == ENOENT || e == ENOTDIR) {
136 exerror(EXEXEC, "%s: not found", argv[0]);
139 exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
145 tryexec(char *cmd, char **argv, char **envp)
151 execve(cmd, argv, envp);
155 in = open(cmd, O_RDONLY | O_NONBLOCK);
157 n = pread(in, buf, sizeof buf, 0);
159 if (n > 0 && memchr(buf, '\0', n) != NULL) {
165 *--argv = __DECONST(char *, _PATH_BSHELL);
166 execve(_PATH_BSHELL, argv, envp);
172 * Do a path search. The variable path (passed by reference) should be
173 * set to the start of the path before the first call; padvance will update
174 * this value as it proceeds. Successive calls to padvance will return
175 * the possible path expansions in sequence. If an option (indicated by
176 * a percent sign) appears in the path entry then the global variable
177 * pathopt will be set to point to it; otherwise pathopt will be set to
184 padvance(const char **path, const char *name)
186 const char *p, *start;
193 for (p = start; *p && *p != ':' && *p != '%'; p++)
195 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
197 CHECKSTRSPACE(len, q);
199 memcpy(q, start, p - start);
207 while (*p && *p != ':') p++;
218 /*** Command hashing code ***/
222 hashcmd(int argc __unused, char **argv __unused)
224 struct tblentry **pp;
225 struct tblentry *cmdp;
228 struct cmdentry entry;
232 while ((c = nextopt("rv")) != '\0') {
235 } else if (c == 'v') {
239 if (*argptr == NULL) {
240 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
241 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
242 if (cmdp->cmdtype == CMDNORMAL)
243 printentry(cmdp, verbose);
248 while ((name = *argptr) != NULL) {
249 if ((cmdp = cmdlookup(name, 0)) != NULL
250 && cmdp->cmdtype == CMDNORMAL)
252 find_command(name, &entry, DO_ERR, pathval());
254 if (entry.cmdtype != CMDUNKNOWN) { /* if no error msg */
255 cmdp = cmdlookup(name, 0);
257 printentry(cmdp, verbose);
259 outfmt(out2, "%s: not found\n", name);
270 printentry(struct tblentry *cmdp, int verbose)
276 if (cmdp->cmdtype == CMDNORMAL) {
277 idx = cmdp->param.index;
280 name = padvance(&path, cmdp->cmdname);
282 } while (--idx >= 0);
284 } else if (cmdp->cmdtype == CMDBUILTIN) {
285 out1fmt("builtin %s", cmdp->cmdname);
286 } else if (cmdp->cmdtype == CMDFUNCTION) {
287 out1fmt("function %s", cmdp->cmdname);
290 name = commandtext(getfuncnode(cmdp->param.func));
298 error("internal error: cmdtype %d", cmdp->cmdtype);
309 * Resolve a command name. If you change this routine, you may have to
310 * change the shellexec routine as well.
314 find_command(const char *name, struct cmdentry *entry, int act,
317 struct tblentry *cmdp, loc_cmd;
326 /* If name contains a slash, don't use the hash table */
327 if (strchr(name, '/') != NULL) {
328 entry->cmdtype = CMDNORMAL;
333 /* If name is in the table, and not invalidated by cd, we're done */
334 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->rehash == 0) {
335 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
341 /* Check for builtin next */
342 if ((i = find_builtin(name, &spec)) >= 0) {
344 cmdp = cmdlookup(name, 1);
345 if (cmdp->cmdtype == CMDFUNCTION)
347 cmdp->cmdtype = CMDBUILTIN;
348 cmdp->param.index = i;
349 cmdp->special = spec;
354 /* We have to search path. */
355 prev = -1; /* where to start */
356 if (cmdp) { /* doing a rehash */
357 if (cmdp->cmdtype == CMDBUILTIN)
360 prev = cmdp->param.index;
366 while ((fullname = padvance(&path, name)) != NULL) {
370 if (prefix("func", pathopt)) {
373 goto loop; /* ignore unimplemented options */
376 /* if rehash, don't redo absolute path names */
377 if (fullname[0] == '/' && idx <= prev) {
380 TRACE(("searchexec \"%s\": no change\n", name));
383 if (stat(fullname, &statb) < 0) {
384 if (errno != ENOENT && errno != ENOTDIR)
388 e = EACCES; /* if we fail, this will be the error */
389 if (!S_ISREG(statb.st_mode))
391 if (pathopt) { /* this is a %func directory */
392 stalloc(strlen(fullname) + 1);
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));
413 cmdp = cmdlookup(name, 1);
414 if (cmdp->cmdtype == CMDFUNCTION)
416 cmdp->cmdtype = CMDNORMAL;
417 cmdp->param.index = idx;
422 /* We failed. If there was an entry for this command, delete it */
423 if (cmdp && cmdp->cmdtype != CMDFUNCTION)
426 if (e == ENOENT || e == ENOTDIR)
427 outfmt(out2, "%s: not found\n", name);
429 outfmt(out2, "%s: %s\n", name, strerror(e));
431 entry->cmdtype = CMDUNKNOWN;
438 entry->cmdtype = cmdp->cmdtype;
439 entry->u = cmdp->param;
440 entry->special = cmdp->special;
442 entry->cmdtype = CMDUNKNOWN;
448 * Search the table of builtin commands.
452 find_builtin(const char *name, int *special)
454 const struct builtincmd *bp;
456 for (bp = builtincmd ; bp->name ; bp++) {
457 if (*bp->name == *name && equal(bp->name, name)) {
458 *special = bp->special;
468 * Called when a cd is done. Marks all commands so the next time they
469 * are executed they will be rehashed.
475 struct tblentry **pp;
476 struct tblentry *cmdp;
478 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
479 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
480 if (cmdp->cmdtype == CMDNORMAL)
489 * Called before PATH is changed. The argument is the new value of PATH;
490 * pathval() still returns the old value at this point. Called with
495 changepath(const char *newval __unused)
502 * Clear out command entries. The argument specifies the first entry in
503 * PATH which has changed.
509 struct tblentry **tblp;
510 struct tblentry **pp;
511 struct tblentry *cmdp;
514 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
516 while ((cmdp = *pp) != NULL) {
517 if (cmdp->cmdtype == CMDNORMAL) {
530 * Locate a command in the command hash table. If "add" is nonzero,
531 * add the command to the table if it is not already present. The
532 * variable "lastcmdentry" is set to point to the address of the link
533 * pointing to the entry, so that delete_cmd_entry can delete the
537 static struct tblentry **lastcmdentry;
540 static struct tblentry *
541 cmdlookup(const char *name, int add)
545 struct tblentry *cmdp;
546 struct tblentry **pp;
553 pp = &cmdtable[hashval % CMDTABLESIZE];
554 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
555 if (equal(cmdp->cmdname, name))
559 if (add && cmdp == NULL) {
561 cmdp = *pp = ckmalloc(sizeof (struct tblentry) - ARB
564 cmdp->cmdtype = CMDUNKNOWN;
566 strcpy(cmdp->cmdname, name);
574 * Delete the command entry returned on the last lookup.
578 delete_cmd_entry(void)
580 struct tblentry *cmdp;
583 cmdp = *lastcmdentry;
584 *lastcmdentry = cmdp->next;
592 * Add a new command entry, replacing any existing command entry for
597 addcmdentry(const char *name, struct cmdentry *entry)
599 struct tblentry *cmdp;
602 cmdp = cmdlookup(name, 1);
603 if (cmdp->cmdtype == CMDFUNCTION) {
604 unreffunc(cmdp->param.func);
606 cmdp->cmdtype = entry->cmdtype;
607 cmdp->param = entry->u;
613 * Define a shell function.
617 defun(const char *name, union node *func)
619 struct cmdentry entry;
622 entry.cmdtype = CMDFUNCTION;
623 entry.u.func = copyfunc(func);
624 addcmdentry(name, &entry);
630 * Delete a function if it exists.
634 unsetfunc(const char *name)
636 struct tblentry *cmdp;
638 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
639 unreffunc(cmdp->param.func);
646 * Shared code for the following builtin commands:
647 * type, command -v, command -V
651 typecmd_impl(int argc, char **argv, int cmd, const char *path)
653 struct cmdentry entry;
654 struct tblentry *cmdp;
655 const char * const *pp;
660 if (path != pathval())
663 for (i = 1; i < argc; i++) {
664 /* First look at the keywords */
665 for (pp = parsekwd; *pp; pp++)
666 if (**pp == *argv[i] && equal(*pp, argv[i]))
670 if (cmd == TYPECMD_SMALLV)
671 out1fmt("%s\n", argv[i]);
673 out1fmt("%s is a shell keyword\n", argv[i]);
677 /* Then look at the aliases */
678 if ((ap = lookupalias(argv[i], 1)) != NULL) {
679 if (cmd == TYPECMD_SMALLV)
680 out1fmt("alias %s='%s'\n", argv[i], ap->val);
682 out1fmt("%s is an alias for %s\n", argv[i],
687 /* Then check if it is a tracked alias */
688 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
689 entry.cmdtype = cmdp->cmdtype;
690 entry.u = cmdp->param;
691 entry.special = cmdp->special;
694 /* Finally use brute force */
695 find_command(argv[i], &entry, 0, path);
698 switch (entry.cmdtype) {
700 if (strchr(argv[i], '/') == NULL) {
701 const char *path2 = path;
703 int j = entry.u.index;
705 name = padvance(&path2, argv[i]);
708 if (cmd == TYPECMD_SMALLV)
709 out1fmt("%s\n", name);
711 out1fmt("%s is%s %s\n", argv[i],
712 (cmdp && cmd == TYPECMD_TYPE) ?
713 " a tracked alias for" : "",
716 if (access(argv[i], X_OK) == 0) {
717 if (cmd == TYPECMD_SMALLV)
718 out1fmt("%s\n", argv[i]);
720 out1fmt("%s is %s\n", argv[i],
723 if (cmd != TYPECMD_SMALLV)
724 outfmt(out2, "%s: %s\n",
725 argv[i], strerror(errno));
732 if (cmd == TYPECMD_SMALLV)
733 out1fmt("%s\n", argv[i]);
735 out1fmt("%s is a shell function\n", argv[i]);
739 if (cmd == TYPECMD_SMALLV)
740 out1fmt("%s\n", argv[i]);
741 else if (entry.special)
742 out1fmt("%s is a special shell builtin\n",
745 out1fmt("%s is a shell builtin\n", argv[i]);
749 if (cmd != TYPECMD_SMALLV)
750 outfmt(out2, "%s: not found\n", argv[i]);
756 if (path != pathval())
763 * Locate and print what a word is...
767 typecmd(int argc, char **argv)
769 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));