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36 * @(#)exec.c 8.4 (Berkeley) 6/8/95
37 * $FreeBSD: head/bin/sh/exec.c 245426 2013-01-14 16:40:50Z jilles $
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 */
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 *);
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;
234 while ((c = nextopt("rv")) != '\0') {
237 } else if (c == 'v') {
241 if (*argptr == NULL) {
242 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
243 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
244 if (cmdp->cmdtype == CMDNORMAL)
245 printentry(cmdp, verbose);
250 while ((name = *argptr) != NULL) {
251 if ((cmdp = cmdlookup(name, 0)) != NULL
252 && cmdp->cmdtype == CMDNORMAL)
254 find_command(name, &entry, DO_ERR, pathval());
255 if (entry.cmdtype == CMDUNKNOWN)
258 cmdp = cmdlookup(name, 0);
260 printentry(cmdp, verbose);
262 outfmt(out2, "%s: not found\n", name);
274 printentry(struct tblentry *cmdp, int verbose)
280 if (cmdp->cmdtype == CMDNORMAL) {
281 idx = cmdp->param.index;
284 name = padvance(&path, cmdp->cmdname);
286 } while (--idx >= 0);
288 } else if (cmdp->cmdtype == CMDBUILTIN) {
289 out1fmt("builtin %s", cmdp->cmdname);
290 } else if (cmdp->cmdtype == CMDFUNCTION) {
291 out1fmt("function %s", cmdp->cmdname);
294 name = commandtext(getfuncnode(cmdp->param.func));
302 error("internal error: cmdtype %d", cmdp->cmdtype);
311 * Resolve a command name. If you change this routine, you may have to
312 * change the shellexec routine as well.
316 find_command(const char *name, struct cmdentry *entry, int act,
319 struct tblentry *cmdp, loc_cmd;
328 /* If name contains a slash, don't use the hash table */
329 if (strchr(name, '/') != NULL) {
330 entry->cmdtype = CMDNORMAL;
337 /* If name is in the table, and not invalidated by cd, we're done */
338 if ((cmdp = cmdlookup(name, 0)) != NULL) {
339 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
345 /* Check for builtin next */
346 if ((i = find_builtin(name, &spec)) >= 0) {
348 cmdp = cmdlookup(name, 1);
349 if (cmdp->cmdtype == CMDFUNCTION)
351 cmdp->cmdtype = CMDBUILTIN;
352 cmdp->param.index = i;
353 cmdp->special = spec;
358 /* We have to search path. */
363 while ((fullname = padvance(&path, name)) != NULL) {
367 if (prefix("func", pathopt)) {
370 goto loop; /* ignore unimplemented options */
373 if (fullname[0] != '/')
375 if (stat(fullname, &statb) < 0) {
376 if (errno != ENOENT && errno != ENOTDIR)
380 e = EACCES; /* if we fail, this will be the error */
381 if (!S_ISREG(statb.st_mode))
383 if (pathopt) { /* this is a %func directory */
384 stalloc(strlen(fullname) + 1);
385 readcmdfile(fullname);
386 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
387 error("%s not defined in %s", name, fullname);
392 if (statb.st_uid == geteuid()) {
393 if ((statb.st_mode & 0100) == 0)
395 } else if (statb.st_gid == getegid()) {
396 if ((statb.st_mode & 010) == 0)
399 if ((statb.st_mode & 01) == 0)
403 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
405 cmdp = cmdlookup(name, 1);
406 if (cmdp->cmdtype == CMDFUNCTION)
408 cmdp->cmdtype = CMDNORMAL;
409 cmdp->param.index = idx;
415 if (e == ENOENT || e == ENOTDIR)
416 outfmt(out2, "%s: not found\n", name);
418 outfmt(out2, "%s: %s\n", name, strerror(e));
420 entry->cmdtype = CMDUNKNOWN;
428 entry->cmdtype = cmdp->cmdtype;
429 entry->u = cmdp->param;
430 entry->special = cmdp->special;
432 entry->cmdtype = CMDUNKNOWN;
438 * Search the table of builtin commands.
442 find_builtin(const char *name, int *special)
444 const struct builtincmd *bp;
446 for (bp = builtincmd ; bp->name ; bp++) {
447 if (*bp->name == *name && equal(bp->name, name)) {
448 *special = bp->special;
458 * Called when a cd is done. If any entry in cmdtable depends on the current
459 * directory, simply clear cmdtable completely.
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 __unused)
485 * Clear out command entries. The argument specifies the first entry in
486 * PATH which has changed.
492 struct tblentry **tblp;
493 struct tblentry **pp;
494 struct tblentry *cmdp;
497 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
499 while ((cmdp = *pp) != NULL) {
500 if (cmdp->cmdtype == CMDNORMAL) {
514 * Locate a command in the command hash table. If "add" is nonzero,
515 * add the command to the table if it is not already present. The
516 * variable "lastcmdentry" is set to point to the address of the link
517 * pointing to the entry, so that delete_cmd_entry can delete the
521 static struct tblentry **lastcmdentry;
524 static struct tblentry *
525 cmdlookup(const char *name, int add)
529 struct tblentry *cmdp;
530 struct tblentry **pp;
537 pp = &cmdtable[hashval % CMDTABLESIZE];
538 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
539 if (equal(cmdp->cmdname, name))
543 if (add && cmdp == NULL) {
545 cmdp = *pp = ckmalloc(sizeof (struct tblentry)
548 cmdp->cmdtype = CMDUNKNOWN;
549 strcpy(cmdp->cmdname, name);
557 * Delete the command entry returned on the last lookup.
561 delete_cmd_entry(void)
563 struct tblentry *cmdp;
566 cmdp = *lastcmdentry;
567 *lastcmdentry = cmdp->next;
575 * Add a new command entry, replacing any existing command entry for
580 addcmdentry(const char *name, struct cmdentry *entry)
582 struct tblentry *cmdp;
585 cmdp = cmdlookup(name, 1);
586 if (cmdp->cmdtype == CMDFUNCTION) {
587 unreffunc(cmdp->param.func);
589 cmdp->cmdtype = entry->cmdtype;
590 cmdp->param = entry->u;
596 * Define a shell function.
600 defun(const char *name, union node *func)
602 struct cmdentry entry;
605 entry.cmdtype = CMDFUNCTION;
606 entry.u.func = copyfunc(func);
607 addcmdentry(name, &entry);
613 * Delete a function if it exists.
617 unsetfunc(const char *name)
619 struct tblentry *cmdp;
621 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
622 unreffunc(cmdp->param.func);
630 * Check if a function by a certain name exists.
633 isfunc(const char *name)
635 struct tblentry *cmdp;
636 cmdp = cmdlookup(name, 0);
637 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION);
642 * Shared code for the following builtin commands:
643 * type, command -v, command -V
647 typecmd_impl(int argc, char **argv, int cmd, const char *path)
649 struct cmdentry entry;
650 struct tblentry *cmdp;
651 const char * const *pp;
656 if (path != pathval())
659 for (i = 1; i < argc; i++) {
660 /* First look at the keywords */
661 for (pp = parsekwd; *pp; pp++)
662 if (**pp == *argv[i] && equal(*pp, argv[i]))
666 if (cmd == TYPECMD_SMALLV)
667 out1fmt("%s\n", argv[i]);
669 out1fmt("%s is a shell keyword\n", argv[i]);
673 /* Then look at the aliases */
674 if ((ap = lookupalias(argv[i], 1)) != NULL) {
675 if (cmd == TYPECMD_SMALLV)
676 out1fmt("alias %s='%s'\n", argv[i], ap->val);
678 out1fmt("%s is an alias for %s\n", argv[i],
683 /* Then check if it is a tracked alias */
684 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
685 entry.cmdtype = cmdp->cmdtype;
686 entry.u = cmdp->param;
687 entry.special = cmdp->special;
690 /* Finally use brute force */
691 find_command(argv[i], &entry, 0, path);
694 switch (entry.cmdtype) {
696 if (strchr(argv[i], '/') == NULL) {
697 const char *path2 = path;
699 int j = entry.u.index;
701 name = padvance(&path2, argv[i]);
704 if (cmd == TYPECMD_SMALLV)
705 out1fmt("%s\n", name);
707 out1fmt("%s is%s %s\n", argv[i],
708 (cmdp && cmd == TYPECMD_TYPE) ?
709 " a tracked alias for" : "",
712 if (access(argv[i], X_OK) == 0) {
713 if (cmd == TYPECMD_SMALLV)
714 out1fmt("%s\n", argv[i]);
716 out1fmt("%s is %s\n", argv[i],
719 if (cmd != TYPECMD_SMALLV)
720 outfmt(out2, "%s: %s\n",
721 argv[i], strerror(errno));
728 if (cmd == TYPECMD_SMALLV)
729 out1fmt("%s\n", argv[i]);
731 out1fmt("%s is a shell function\n", argv[i]);
735 if (cmd == TYPECMD_SMALLV)
736 out1fmt("%s\n", argv[i]);
737 else if (entry.special)
738 out1fmt("%s is a special shell builtin\n",
741 out1fmt("%s is a shell builtin\n", argv[i]);
745 if (cmd != TYPECMD_SMALLV)
746 outfmt(out2, "%s: not found\n", argv[i]);
752 if (path != pathval())
759 * Locate and print what a word is...
763 typecmd(int argc, char **argv)
765 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));