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36 static char sccsid[] = "@(#)exec.c 8.1 (Berkeley) 5/31/93";
38 static const char rcsid[] =
39 "$Id: exec.c,v 1.7 1997/08/07 21:42:07 steve Exp $";
43 #include <sys/param.h>
61 * System level search and execute of a command. We look in each directory
62 * for the specified command name. If the name contains a '/' then we
63 * execute only the full path name. If there is no search path then we
64 * execute only full path names.
66 extern char **environ;
69 * As we search for the command we note the first non-trivial error
70 * message for presentation to the user. This allows us often
71 * to show that a file has the wrong mode/no access when the file
72 * is not in the last component of the search path, so we must
73 * go on after first detecting the error.
75 static char *exerr; /* Execution error message */
76 static Char *expath; /* Path for exerr */
79 * Xhash is an array of HSHSIZ bits (HSHSIZ / 8 chars), which are used
80 * to hash execs. If it is allocated (havhash true), then to tell
81 * whether ``name'' is (possibly) present in the i'th component
82 * of the variable path, you look at the bit in xhash indexed by
83 * hash(hashname("name"), i). This is setup automatically
84 * after .login is executed, and recomputed whenever ``path'' is
86 * The two part hash function is designed to let texec() call the
87 * more expensive hashname() only once and the simple hash() several
88 * times (once for each path component checked).
89 * Byte size is assumed to be 8.
91 #define HSHSIZ 8192 /* 1k bytes */
92 #define HSHMASK (HSHSIZ - 1)
94 static char xhash[HSHSIZ / 8];
96 #define hash(a, b) (((a) * HSHMUL + (b)) & HSHMASK)
97 #define bit(h, b) ((h)[(b) >> 3] & 1 << ((b) & 7)) /* bit test */
98 #define bis(h, b) ((h)[(b) >> 3] |= 1 << ((b) & 7)) /* bit set */
99 static int hits, misses;
101 /* Dummy search path for just absolute search when no path */
102 static Char *justabs[] = {STRNULL, 0};
104 static void pexerr __P((void));
105 static void texec __P((Char *, Char **));
106 static int hashname __P((Char *));
107 static void tellmewhat __P((struct wordent *));
108 static int executable __P((Char *, Char *, bool));
109 static int iscommand __P((Char *));
118 Char *dp, **pv, **av, *sav;
119 struct varent *pathv;
121 int hashval = 0, hashval1, i;
125 * Glob the command name. We will search $path even if this does something,
126 * as in sh but not in csh. One special case: if there is no PATH, then we
127 * execute only commands which start with '/'.
129 blk[0] = t->t_dcom[0];
131 gflag = 0, tglob(blk);
135 setname(vis_str(blk[0]));
136 stderror(ERR_NAME | ERR_NOMATCH);
146 expath = Strsave(pv[0]);
149 pathv = adrof(STRpath);
150 if (pathv == 0 && expath[0] != '/') {
154 slash = any(short2str(expath), '/');
157 * Glob the argument list, if necessary. Otherwise trim off the quote bits.
166 setname(vis_str(expath));
167 stderror(ERR_NAME | ERR_NOMATCH);
175 t->t_dcom = blkspl(pv, av);
181 if (*av == NULL || **av == '\0')
184 xechoit(av); /* Echo command if -x */
186 * Since all internal file descriptors are set to close on exec, we don't
187 * need to close them explicitly here. Just reorient ourselves for error
195 * We must do this AFTER any possible forking (like `foo` in glob) so that
196 * this shell can still do subprocesses.
198 (void) sigsetmask((sigset_t) 0);
200 * If no path, no words in path, or a / in the filename then restrict the
203 if (pathv == 0 || pathv->vec[0] == 0 || slash)
207 sav = Strspl(STRslash, *av);/* / command name for postpending */
210 hashval = hashname(*av);
215 * Try to save time by looking at the hash table for where this command
216 * could be. If we are doing delayed hashing, then we put the names in
217 * one at a time, as the user enters them. This is kinda like Korn
218 * Shell's "tracked aliases".
220 if (!slash && pv[0][0] == '/' && havhash) {
221 hashval1 = hash(hashval, i);
222 if (!bit(xhash, hashval1))
225 if (pv[0][0] == 0 || eq(pv[0], STRdot)) /* don't make ./xxx */
228 dp = Strspl(*pv, sav);
248 /* Couldn't find the damn thing */
250 setname(vis_str(expath));
252 xfree((ptr_t) expath);
258 stderror(ERR_NAME | ERR_STRING, exerr);
259 stderror(ERR_NAME | ERR_COMMAND);
263 * Execute command f, arg list t.
264 * Record error message if not found.
265 * Also do shell scripts here.
281 /* The order for the conversions is significant */
285 errno = 0; /* don't use a previous error */
286 (void) execve(f, t, environ);
288 blkfree((Char **) t);
293 * From: casper@fwi.uva.nl (Casper H.S. Dik) If we could not execute
294 * it, don't feed it to the shell if it looks like a binary!
296 if ((fd = open(f, O_RDONLY)) != -1) {
297 if (read(fd, (char *) &c, 1) == 1) {
298 if (!Isprint(c) && (c != '\n' && c != '\t')) {
301 * We *know* what ENOEXEC means.
303 stderror(ERR_ARCH, f, strerror(errno));
313 * If there is an alias for shell, then put the words of the alias in
314 * front of the argument list replacing the command name. Note no
315 * interpretation of the words at this point.
317 v = adrof1(STRshell, &aliases);
320 vp[0] = adrof(STRshell) ? value(STRshell) : STR_SHELLPATH;
323 if (fd != -1 && c != '#')
332 st = blkspl(vp, st); /* Splice up the new arglst */
335 /* The order for the conversions is significant */
340 (void) execve(f, t, environ);
342 blkfree((Char **) t);
343 /* The sky is falling, the sky is falling! */
346 stderror(ERR_SYSTEM, f, strerror(errno));
353 exerr = strerror(errno);
355 xfree((ptr_t) expath);
356 expath = Strsave(sf);
368 int saveIN, saveOUT, saveDIAG, saveSTD;
376 sig_t osigint, osigquit, osigterm;
378 if (chkstop == 0 && setintr)
381 * Hmm, we don't really want to do that now because we might
382 * fail, but what is the choice
386 osigint = signal(SIGINT, parintr);
387 osigquit = signal(SIGQUIT, parintr);
388 osigterm = signal(SIGTERM, parterm);
396 saveIN = dcopy(SHIN, -1);
397 saveOUT = dcopy(SHOUT, -1);
398 saveDIAG = dcopy(SHERR, -1);
399 saveSTD = dcopy(OLDSTD, -1);
401 lshift(kp->t_dcom, 1);
405 if ((my_reenter = setexit()) == 0) {
407 SHOUT = dcopy(1, -1);
408 SHERR = dcopy(2, -1);
413 (void) signal(SIGINT, osigint);
414 (void) signal(SIGQUIT, osigquit);
415 (void) signal(SIGTERM, osigterm);
422 (void) close(OLDSTD);
423 SHIN = dmove(saveIN, oSHIN);
424 SHOUT = dmove(saveOUT, oSHOUT);
425 SHERR = dmove(saveDIAG, oSHERR);
426 OLDSTD = dmove(saveSTD, oOLDSTD);
430 stderror(ERR_SILENT);
437 if (adrof(STRecho)) {
438 (void) fflush(csherr);
440 (void) fputc('\n', csherr);
454 struct varent *pathv = adrof(STRpath);
459 for (cnt = 0; cnt < sizeof xhash; cnt++)
463 for (pv = pathv->vec; *pv; pv++, i++) {
466 dirp = opendir(short2str(*pv));
469 while ((dp = readdir(dirp)) != NULL) {
472 if (dp->d_name[0] == '.' &&
473 (dp->d_name[1] == '\0' ||
474 (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
476 hashval = hash(hashname(str2short(dp->d_name)), i);
478 /* tw_add_comm_name (dp->d_name); */
480 (void) closedir(dirp);
500 (void) fprintf(cshout, "%d hits, %d misses, %d%%\n",
501 hits, misses, 100 * hits / (hits + misses));
505 * Hash a command name.
525 bool slash = any(short2str(name), '/');
526 int hashval = 0, hashval1, i;
529 if (v == 0 || v->vec[0] == 0 || slash)
533 sav = Strspl(STRslash, name); /* / command name for postpending */
535 hashval = hashname(name);
538 if (!slash && pv[0][0] == '/' && havhash) {
539 hashval1 = hash(hashval, i);
540 if (!bit(xhash, hashval1))
543 if (pv[0][0] == 0 || eq(pv[0], STRdot)) { /* don't make ./xxx */
544 if (executable(NULL, name, 0)) {
550 if (executable(*pv, sav, 0)) {
564 * Andreas Luik <luik@isaak.isa.de>
565 * I S A GmbH - Informationssysteme fuer computerintegrierte Automatisierung
569 * is the executable() routine below and changes to iscommand().
574 * executable() examines the pathname obtained by concatenating dir and name
575 * (dir may be NULL), and returns 1 either if it is executable by us, or
576 * if dir_ok is set and the pathname refers to a directory.
577 * This is a bit kludgy, but in the name of optimization...
580 executable(dir, name, dir_ok)
585 Char path[MAXPATHLEN + 1], *dp, *sp;
589 for (dp = path, sp = dir; *sp; *dp++ = *sp++)
590 if (dp == &path[MAXPATHLEN + 1]) {
594 for (sp = name; *sp; *dp++ = *sp++)
595 if (dp == &path[MAXPATHLEN + 1]) {
600 strname = short2str(path);
603 strname = short2str(name);
604 return (stat(strname, &stbuf) != -1 &&
605 ((S_ISREG(stbuf.st_mode) &&
606 /* save time by not calling access() in the hopeless case */
607 (stbuf.st_mode & (S_IXOTH | S_IXGRP | S_IXUSR)) &&
608 access(strname, X_OK) == 0) ||
609 (dir_ok && S_ISDIR(stbuf.st_mode))));
612 /* The dowhich() is by:
613 * Andreas Luik <luik@isaak.isa.de>
614 * I S A GmbH - Informationssysteme fuer computerintegrierte Automatisierung
626 struct wordent lex[3];
629 lex[0].next = &lex[1];
630 lex[1].next = &lex[2];
631 lex[2].next = &lex[0];
633 lex[0].prev = &lex[2];
634 lex[1].prev = &lex[0];
635 lex[2].prev = &lex[1];
637 lex[0].word = STRNULL;
638 lex[2].word = STRret;
641 if ((vp = adrof1(*v, &aliases)) != NULL) {
642 (void) fprintf(cshout, "%s: \t aliased to ", vis_str(*v));
643 blkpr(cshout, vp->vec);
644 (void) fputc('\n', cshout);
658 struct biltins *bptr;
659 struct wordent *sp = lex->next;
661 Char *s0, *s1, *s2, *cmd;
664 if (adrof1(sp->word, &aliases)) {
670 s0 = sp->word; /* to get the memory freeing right... */
672 /* handle quoted alias hack */
673 if ((*(sp->word) & (QUOTE | TRIM)) == QUOTE)
676 /* do quoting, if it hasn't been done */
683 while (*s2 && *s2 != qc)
684 *s1++ = *s2++ | QUOTE;
690 *s1++ = *s2++ | QUOTE;
697 for (bptr = bfunc; bptr < &bfunc[nbfunc]; bptr++) {
698 if (eq(sp->word, str2short(bptr->bname))) {
701 (void) fprintf(cshout, "%s: shell built-in command.\n",
703 sp->word = s0; /* we save and then restore this */
708 sp->word = cmd = globone(sp->word, G_IGNORE);
710 if ((i = iscommand(strip(sp->word))) != 0) {
713 bool slash = any(short2str(sp->word), '/');
716 if (v == 0 || v->vec[0] == 0 || slash)
723 if (pv[0][0] == 0 || eq(pv[0], STRdot)) {
725 sp->word = Strspl(STRdotsl, sp->word);
727 xfree((ptr_t) sp->word);
730 sp->word = s0; /* we save and then restore this */
734 s1 = Strspl(*pv, STRslash);
735 sp->word = Strspl(s1, sp->word);
738 xfree((ptr_t) sp->word);
743 (void) fprintf(csherr, "%s: Command not found.\n", vis_str(sp->word));
746 sp->word = s0; /* we save and then restore this */