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32 * @(#)exec.c 8.4 (Berkeley) 6/8/95
33 * $FreeBSD: head/bin/sh/exec.c 253650 2013-07-25 15:08:41Z jilles $
36 #include <sys/types.h>
45 * When commands are first encountered, they are entered in a hash table.
46 * This ensures that a full path search will not have to be done for them
49 * We should investigate converting to a linear search, even though that
50 * would make the command name "hash" a misnomer.
74 #define CMDTABLESIZE 31 /* should be prime */
79 struct tblentry *next; /* next entry in hash chain */
80 union param param; /* definition of builtin function */
81 int special; /* flag for special builtin commands */
82 signed char cmdtype; /* index identifying command */
83 char cmdname[]; /* name of command */
87 static struct tblentry *cmdtable[CMDTABLESIZE];
88 static int cmdtable_cd = 0; /* cmdtable contains cd-dependent entries */
89 int exerrno = 0; /* Last exec error */
92 static void tryexec(char *, char **, char **);
93 static void printentry(struct tblentry *, int);
94 static struct tblentry *cmdlookup(const char *, int);
95 static void delete_cmd_entry(void);
96 static void addcmdentry(const char *, struct cmdentry *);
99 * Exec a program. Never returns. If you change this routine, you may
100 * have to change the find_command routine as well.
102 * The argv array may be changed and element argv[-1] should be writable.
106 shellexec(char **argv, char **envp, const char *path, int idx)
111 if (strchr(argv[0], '/') != NULL) {
112 tryexec(argv[0], argv, envp);
116 while ((cmdname = padvance(&path, argv[0])) != NULL) {
117 if (--idx < 0 && pathopt == NULL) {
118 tryexec(cmdname, argv, envp);
119 if (errno != ENOENT && errno != ENOTDIR)
128 /* Map to POSIX errors */
129 if (e == ENOENT || e == ENOTDIR) {
131 exerror(EXEXEC, "%s: not found", argv[0]);
134 exerror(EXEXEC, "%s: %s", argv[0], strerror(e));
140 tryexec(char *cmd, char **argv, char **envp)
146 execve(cmd, argv, envp);
150 in = open(cmd, O_RDONLY | O_NONBLOCK);
152 n = pread(in, buf, sizeof buf, 0);
154 if (n > 0 && memchr(buf, '\0', n) != NULL) {
160 *--argv = __DECONST(char *, _PATH_BSHELL);
161 execve(_PATH_BSHELL, argv, envp);
167 * Do a path search. The variable path (passed by reference) should be
168 * set to the start of the path before the first call; padvance will update
169 * this value as it proceeds. Successive calls to padvance will return
170 * the possible path expansions in sequence. If an option (indicated by
171 * a percent sign) appears in the path entry then the global variable
172 * pathopt will be set to point to it; otherwise pathopt will be set to
179 padvance(const char **path, const char *name)
181 const char *p, *start;
188 for (p = start; *p && *p != ':' && *p != '%'; p++)
190 len = p - start + strlen(name) + 2; /* "2" is for '/' and '\0' */
192 CHECKSTRSPACE(len, q);
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;
229 while ((c = nextopt("rv")) != '\0') {
232 } else if (c == 'v') {
236 if (*argptr == NULL) {
237 for (pp = cmdtable ; pp < &cmdtable[CMDTABLESIZE] ; pp++) {
238 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
239 if (cmdp->cmdtype == CMDNORMAL)
240 printentry(cmdp, verbose);
245 while ((name = *argptr) != NULL) {
246 if ((cmdp = cmdlookup(name, 0)) != NULL
247 && cmdp->cmdtype == CMDNORMAL)
249 find_command(name, &entry, DO_ERR, pathval());
250 if (entry.cmdtype == CMDUNKNOWN)
253 cmdp = cmdlookup(name, 0);
255 printentry(cmdp, verbose);
257 outfmt(out2, "%s: not found\n", name);
269 printentry(struct tblentry *cmdp, int verbose)
275 if (cmdp->cmdtype == CMDNORMAL) {
276 idx = cmdp->param.index;
279 name = padvance(&path, cmdp->cmdname);
281 } while (--idx >= 0);
283 } else if (cmdp->cmdtype == CMDBUILTIN) {
284 out1fmt("builtin %s", cmdp->cmdname);
285 } else if (cmdp->cmdtype == CMDFUNCTION) {
286 out1fmt("function %s", cmdp->cmdname);
289 name = commandtext(getfuncnode(cmdp->param.func));
297 error("internal error: cmdtype %d", cmdp->cmdtype);
306 * Resolve a command name. If you change this routine, you may have to
307 * change the shellexec routine as well.
311 find_command(const char *name, struct cmdentry *entry, int act,
314 struct tblentry *cmdp, loc_cmd;
323 /* If name contains a slash, don't use the hash table */
324 if (strchr(name, '/') != NULL) {
325 entry->cmdtype = CMDNORMAL;
332 /* If name is in the table, and not invalidated by cd, we're done */
333 if ((cmdp = cmdlookup(name, 0)) != NULL) {
334 if (cmdp->cmdtype == CMDFUNCTION && act & DO_NOFUNC)
340 /* Check for builtin next */
341 if ((i = find_builtin(name, &spec)) >= 0) {
343 cmdp = cmdlookup(name, 1);
344 if (cmdp->cmdtype == CMDFUNCTION)
346 cmdp->cmdtype = CMDBUILTIN;
347 cmdp->param.index = i;
348 cmdp->special = spec;
353 /* We have to search path. */
358 while ((fullname = padvance(&path, name)) != NULL) {
362 if (prefix("func", pathopt)) {
365 goto loop; /* ignore unimplemented options */
368 if (fullname[0] != '/')
370 if (stat(fullname, &statb) < 0) {
371 if (errno != ENOENT && errno != ENOTDIR)
375 e = EACCES; /* if we fail, this will be the error */
376 if (!S_ISREG(statb.st_mode))
378 if (pathopt) { /* this is a %func directory */
379 stalloc(strlen(fullname) + 1);
380 readcmdfile(fullname);
381 if ((cmdp = cmdlookup(name, 0)) == NULL || cmdp->cmdtype != CMDFUNCTION)
382 error("%s not defined in %s", name, fullname);
387 if (statb.st_uid == geteuid()) {
388 if ((statb.st_mode & 0100) == 0)
390 } else if (statb.st_gid == getegid()) {
391 if ((statb.st_mode & 010) == 0)
394 if ((statb.st_mode & 01) == 0)
398 TRACE(("searchexec \"%s\" returns \"%s\"\n", name, fullname));
400 cmdp = cmdlookup(name, 1);
401 if (cmdp->cmdtype == CMDFUNCTION)
403 cmdp->cmdtype = CMDNORMAL;
404 cmdp->param.index = idx;
410 if (e == ENOENT || e == ENOTDIR)
411 outfmt(out2, "%s: not found\n", name);
413 outfmt(out2, "%s: %s\n", name, strerror(e));
415 entry->cmdtype = CMDUNKNOWN;
423 entry->cmdtype = cmdp->cmdtype;
424 entry->u = cmdp->param;
425 entry->special = cmdp->special;
427 entry->cmdtype = CMDUNKNOWN;
433 * Search the table of builtin commands.
437 find_builtin(const char *name, int *special)
439 const struct builtincmd *bp;
441 for (bp = builtincmd ; bp->name ; bp++) {
442 if (*bp->name == *name && equal(bp->name, name)) {
443 *special = bp->special;
453 * Called when a cd is done. If any entry in cmdtable depends on the current
454 * directory, simply clear cmdtable completely.
467 * Called before PATH is changed. The argument is the new value of PATH;
468 * pathval() still returns the old value at this point. Called with
473 changepath(const char *newval __unused)
480 * Clear out command entries. The argument specifies the first entry in
481 * PATH which has changed.
487 struct tblentry **tblp;
488 struct tblentry **pp;
489 struct tblentry *cmdp;
492 for (tblp = cmdtable ; tblp < &cmdtable[CMDTABLESIZE] ; tblp++) {
494 while ((cmdp = *pp) != NULL) {
495 if (cmdp->cmdtype == CMDNORMAL) {
509 * Locate a command in the command hash table. If "add" is nonzero,
510 * add the command to the table if it is not already present. The
511 * variable "lastcmdentry" is set to point to the address of the link
512 * pointing to the entry, so that delete_cmd_entry can delete the
516 static struct tblentry **lastcmdentry;
519 static struct tblentry *
520 cmdlookup(const char *name, int add)
524 struct tblentry *cmdp;
525 struct tblentry **pp;
532 pp = &cmdtable[hashval % CMDTABLESIZE];
533 for (cmdp = *pp ; cmdp ; cmdp = cmdp->next) {
534 if (equal(cmdp->cmdname, name))
538 if (add && cmdp == NULL) {
540 cmdp = *pp = ckmalloc(sizeof (struct tblentry)
543 cmdp->cmdtype = CMDUNKNOWN;
544 strcpy(cmdp->cmdname, name);
552 * Delete the command entry returned on the last lookup.
556 delete_cmd_entry(void)
558 struct tblentry *cmdp;
561 cmdp = *lastcmdentry;
562 *lastcmdentry = cmdp->next;
570 * Add a new command entry, replacing any existing command entry for
575 addcmdentry(const char *name, struct cmdentry *entry)
577 struct tblentry *cmdp;
580 cmdp = cmdlookup(name, 1);
581 if (cmdp->cmdtype == CMDFUNCTION) {
582 unreffunc(cmdp->param.func);
584 cmdp->cmdtype = entry->cmdtype;
585 cmdp->param = entry->u;
591 * Define a shell function.
595 defun(const char *name, union node *func)
597 struct cmdentry entry;
600 entry.cmdtype = CMDFUNCTION;
601 entry.u.func = copyfunc(func);
602 addcmdentry(name, &entry);
608 * Delete a function if it exists.
612 unsetfunc(const char *name)
614 struct tblentry *cmdp;
616 if ((cmdp = cmdlookup(name, 0)) != NULL && cmdp->cmdtype == CMDFUNCTION) {
617 unreffunc(cmdp->param.func);
625 * Check if a function by a certain name exists.
628 isfunc(const char *name)
630 struct tblentry *cmdp;
631 cmdp = cmdlookup(name, 0);
632 return (cmdp != NULL && cmdp->cmdtype == CMDFUNCTION);
637 * Shared code for the following builtin commands:
638 * type, command -v, command -V
642 typecmd_impl(int argc, char **argv, int cmd, const char *path)
644 struct cmdentry entry;
645 struct tblentry *cmdp;
646 const char * const *pp;
651 if (path != pathval())
654 for (i = 1; i < argc; i++) {
655 /* First look at the keywords */
656 for (pp = parsekwd; *pp; pp++)
657 if (**pp == *argv[i] && equal(*pp, argv[i]))
661 if (cmd == TYPECMD_SMALLV)
662 out1fmt("%s\n", argv[i]);
664 out1fmt("%s is a shell keyword\n", argv[i]);
668 /* Then look at the aliases */
669 if ((ap = lookupalias(argv[i], 1)) != NULL) {
670 if (cmd == TYPECMD_SMALLV)
671 out1fmt("alias %s='%s'\n", argv[i], ap->val);
673 out1fmt("%s is an alias for %s\n", argv[i],
678 /* Then check if it is a tracked alias */
679 if ((cmdp = cmdlookup(argv[i], 0)) != NULL) {
680 entry.cmdtype = cmdp->cmdtype;
681 entry.u = cmdp->param;
682 entry.special = cmdp->special;
685 /* Finally use brute force */
686 find_command(argv[i], &entry, 0, path);
689 switch (entry.cmdtype) {
691 if (strchr(argv[i], '/') == NULL) {
692 const char *path2 = path;
694 int j = entry.u.index;
696 name = padvance(&path2, argv[i]);
699 if (cmd == TYPECMD_SMALLV)
700 out1fmt("%s\n", name);
702 out1fmt("%s is%s %s\n", argv[i],
703 (cmdp && cmd == TYPECMD_TYPE) ?
704 " a tracked alias for" : "",
707 if (access(argv[i], X_OK) == 0) {
708 if (cmd == TYPECMD_SMALLV)
709 out1fmt("%s\n", argv[i]);
711 out1fmt("%s is %s\n", argv[i],
714 if (cmd != TYPECMD_SMALLV)
715 outfmt(out2, "%s: %s\n",
716 argv[i], strerror(errno));
723 if (cmd == TYPECMD_SMALLV)
724 out1fmt("%s\n", argv[i]);
726 out1fmt("%s is a shell function\n", argv[i]);
730 if (cmd == TYPECMD_SMALLV)
731 out1fmt("%s\n", argv[i]);
732 else if (entry.special)
733 out1fmt("%s is a special shell builtin\n",
736 out1fmt("%s is a shell builtin\n", argv[i]);
740 if (cmd != TYPECMD_SMALLV)
741 outfmt(out2, "%s: not found\n", argv[i]);
747 if (path != pathval())
754 * Locate and print what a word is...
758 typecmd(int argc, char **argv)
760 return typecmd_impl(argc, argv, TYPECMD_TYPE, bltinlookup("PATH", 1));