xref: /illumos-gate/usr/src/cmd/csh/sh.dir.c (revision 6446bd46ed1b4e9f69da153665f82181ccaedad5)
1 /*
2  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  * Copyright (c) 2016 by Delphix. All rights reserved.
5  */
6 
7 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
8 /*	  All Rights Reserved  	*/
9 
10 /*
11  * Copyright (c) 1980 Regents of the University of California.
12  * All rights reserved.  The Berkeley Software License Agreement
13  * specifies the terms and conditions for redistribution.
14  */
15 
16 #include "sh.h"
17 #include "sh.dir.h"
18 #include "sh.tconst.h"
19 
20 /*
21  * C Shell - directory management
22  */
23 
24 struct directory	*dfind(tchar *);
25 tchar	*dfollow(tchar *);
26 tchar	*dcanon(tchar *, tchar *);
27 void	dtildepr(tchar *, tchar *);
28 void	dfree(struct directory *);
29 void	dnewcwd(struct directory *);
30 
31 int	didchdir;
32 bool	loginsh;
33 bool	havhash2;
34 struct varent shvhed;
35 struct directory *dcwd;
36 struct	directory dhead;		/* "head" of loop */
37 int	printd;				/* force name to be printed */
38 static tchar *fakev[] = { S_dirs, NOSTR };
39 char	xhash2[HSHSIZ / 8];
40 
41 /*
42  * dinit - initialize current working directory
43  */
44 void
45 dinit(tchar *hp)
46 {
47 	tchar *cp;
48 	struct directory *dp;
49 	tchar path[MAXPATHLEN];
50 
51 #ifdef TRACE
52 	tprintf("TRACE- dinit()\n");
53 #endif
54 	/*
55 	 * If this is a login shell, we should have a home directory.  But,
56 	 * if we got here via 'su - <user>' where the user has no directory
57 	 * in their passwd file, then su has passed HOME=<nothing>, so hp is
58 	 * non-null, but has zero length.  Thus, we do not know the current
59 	 * working directory based on the home directory.
60 	 */
61 	if (loginsh && hp && *hp)
62 		cp = hp;
63 	else {
64 		cp = getwd_(path);
65 		if (cp == NULL) {
66 			printf("Warning: cannot determine current directory\n");
67 			cp = S_DOT;
68 		}
69 	}
70 	dp = (struct directory *)xcalloc(sizeof (struct directory), 1);
71 	dp->di_name = savestr(cp);
72 	dp->di_count = 0;
73 	dhead.di_next = dhead.di_prev = dp;
74 	dp->di_next = dp->di_prev = &dhead;
75 	printd = 0;
76 	dnewcwd(dp);
77 }
78 
79 /*
80  * dodirs - list all directories in directory loop
81  */
82 void
83 dodirs(tchar **v)
84 {
85 	struct directory *dp;
86 	bool lflag;
87 	tchar *hp = value(S_home);
88 
89 #ifdef TRACE
90 	tprintf("TRACE- dodirs()\n");
91 #endif
92 	if (*hp == '\0')
93 		hp = NOSTR;
94 	if (*++v != NOSTR)
95 		if (eq(*v, S_MINl /* "-l" */) && *++v == NOSTR)
96 			lflag = 1;
97 		else
98 			error("Usage: dirs [ -l ]");
99 	else
100 		lflag = 0;
101 	dp = dcwd;
102 	do {
103 		if (dp == &dhead)
104 			continue;
105 		if (!lflag && hp != NOSTR) {
106 			dtildepr(hp, dp->di_name);
107 		} else
108 			printf("%t", dp->di_name);
109 		printf(" ");
110 	} while ((dp = dp->di_prev) != dcwd);
111 	printf("\n");
112 }
113 
114 void
115 dtildepr(tchar *home, tchar *dir)
116 {
117 
118 #ifdef TRACE
119 	tprintf("TRACE- dtildepr()\n");
120 #endif
121 	if (!eq(home, S_SLASH /* "/" */) && prefix(home, dir))
122 		printf("~%t", dir + strlen_(home));
123 	else
124 		printf("%t", dir);
125 }
126 
127 /*
128  * dochngd - implement chdir command.
129  */
130 void
131 dochngd(tchar **v)
132 {
133 	tchar *cp;
134 	struct directory *dp;
135 
136 #ifdef TRACE
137 	tprintf("TRACE- dochngd()\n");
138 #endif
139 	printd = 0;
140 	if (*++v == NOSTR) {
141 		if ((cp = value(S_home)) == NOSTR || *cp == 0)
142 			bferr("No home directory");
143 		if (chdir_(cp) < 0)
144 			bferr("Can't change to home directory");
145 		cp = savestr(cp);
146 	} else if ((dp = dfind(*v)) != 0) {
147 		printd = 1;
148 		if (chdir_(dp->di_name) < 0)
149 			Perror(dp->di_name);
150 		dcwd->di_prev->di_next = dcwd->di_next;
151 		dcwd->di_next->di_prev = dcwd->di_prev;
152 		goto flushcwd;
153 	} else
154 		cp = dfollow(*v);
155 	dp = (struct directory *)xcalloc(sizeof (struct directory), 1);
156 	dp->di_name = cp;
157 	dp->di_count = 0;
158 	dp->di_next = dcwd->di_next;
159 	dp->di_prev = dcwd->di_prev;
160 	dp->di_prev->di_next = dp;
161 	dp->di_next->di_prev = dp;
162 flushcwd:
163 	dfree(dcwd);
164 	dnewcwd(dp);
165 }
166 
167 /*
168  * dfollow - change to arg directory; fall back on cdpath if not valid
169  */
170 tchar *
171 dfollow(tchar *cp)
172 {
173 	tchar *dp;
174 	struct varent *c;
175 	int cdhashval, cdhashval1;
176 	int index;
177 	int slash; /* slashes in the argument */
178 	tchar *fullpath;
179 	tchar *slashcp; /* cp string prepended with a slash */
180 
181 #ifdef TRACE
182 	tprintf("TRACE- dfollow()\n");
183 #endif
184 	cp = globone(cp);
185 	if (chdir_(cp) >= 0)
186 		goto gotcha;
187 
188 	/*
189 	 * If the directory argument has a slash in it,
190 	 * for example, directory/directory, then can't
191 	 * find that in the cache table.
192 	 */
193 	slash = any('/', cp);
194 
195 	/*
196 	 * Try interpreting wrt successive components of cdpath.
197 	 * cdpath caching is turned off or directory argument
198 	 * has a slash in it.
199 	 */
200 	if (cp[0] != '/'
201 	    && !prefix(S_DOTSLA /* "./" */, cp)
202 	    && !prefix(S_DOTDOTSLA /* "../" */, cp)
203 	    && (c = adrof(S_cdpath))
204 	    && (!havhash2 || slash)) {
205 		tchar **cdp;
206 		tchar *p;
207 		tchar buf[MAXPATHLEN];
208 
209 		for (cdp = c->vec; *cdp; cdp++) {
210 			for (dp = buf, p = *cdp; *dp++ = *p++; )
211 				;
212 			dp[-1] = '/';
213 			for (p = cp; *dp++ = *p++; )
214 				;
215 			if (chdir_(buf) >= 0) {
216 				printd = 1;
217 				xfree(cp);
218 				cp = savestr(buf);
219 				goto gotcha;
220 			}
221 		}
222 	}
223 
224 	/* cdpath caching turned on */
225 	if (cp[0] != '/'
226 	    && !prefix(S_DOTSLA /* "./" */, cp)
227 	    && !prefix(S_DOTDOTSLA /* "../" */, cp)
228 	    && (c = adrof(S_cdpath))
229 	    && havhash2 && !slash) {
230 		tchar **pv;
231 
232 		/* If no cdpath or no paths in cdpath, leave */
233 		if (c == 0 || c->vec[0] == 0)
234 			pv = justabs;
235 		else
236 			pv = c->vec;
237 
238 		slashcp = strspl(S_SLASH, cp);
239 
240 		cdhashval = hashname(cp);
241 
242 		/* index points to next path component to test */
243 		index = 0;
244 
245 		/*
246 		 * Look at each path in cdpath until get a match.
247 		 * Only look at those path beginning with a slash
248 		 */
249 		do {
250 			/* only check cache for absolute pathnames */
251 			if (pv[0][0] == '/') {
252 				cdhashval1 = hash(cdhashval, index);
253 				if (bit(xhash2, cdhashval1)) {
254 					/*
255 					 * concatenate found path with
256 					 * arg directory
257 					 */
258 					fullpath = strspl(*pv, slashcp);
259 					if (chdir_(fullpath) >= 0) {
260 						printd = 1;
261 						xfree(cp);
262 						cp = savestr(fullpath);
263 						xfree(slashcp);
264 						xfree(fullpath);
265 						goto gotcha;
266 					}
267 				}
268 			}
269 			/*
270 			 * relative pathnames are not cached, and must be
271 			 * checked manually
272 			 */
273 			else {
274 				tchar *p;
275 				tchar buf[MAXPATHLEN];
276 
277 				for (dp = buf, p = *pv; *dp++ = *p++; )
278 					;
279 				dp[-1] = '/';
280 				for (p = cp; *dp++ = *p++; )
281 					;
282 				if (chdir_(buf) >= 0) {
283 					printd = 1;
284 					xfree(cp);
285 					cp = savestr(buf);
286 					xfree(slashcp);
287 					goto gotcha;
288 				}
289 			}
290 			pv++;
291 			index++;
292 		} while (*pv);
293 	}
294 
295 	/*
296 	 * Try dereferencing the variable named by the argument.
297 	 */
298 	dp = value(cp);
299 	if ((dp[0] == '/' || dp[0] == '.') && chdir_(dp) >= 0) {
300 		xfree(cp);
301 		cp = savestr(dp);
302 		printd = 1;
303 		goto gotcha;
304 	}
305 	xfree(cp);			/* XXX, use after free */
306 	Perror(cp);
307 
308 gotcha:
309 	if (*cp != '/') {
310 		tchar *p, *q;
311 		int cwdlen;
312 		int len;
313 
314 		/*
315 		 * All in the name of efficiency?
316 		 */
317 
318 		if ((cwdlen = (strlen_(dcwd->di_name))) == 1) {
319 			if (*dcwd->di_name == '/') /* root */
320 				cwdlen = 0;
321 			else
322 			{
323 				/*
324 				 * if we are here, when the shell started
325 				 * it was unable to getwd(), lets try it again
326 				 */
327 				tchar path[MAXPATHLEN];
328 
329 				p = getwd_(path);
330 				if (p == NULL)
331 					error("cannot determine current directory");
332 				else
333 				{
334 					xfree(dcwd->di_name);
335 					dcwd->di_name = savestr(p);
336 					xfree(cp);
337 					cp = savestr(p);
338 					return dcanon(cp, cp);
339 				}
340 
341 			}
342 		}
343 		/*
344 		 *
345 		 * for (p = cp; *p++;)
346 		 * 	;
347 		 * dp = (tchar *)xalloc((unsigned) (cwdlen + (p - cp) + 1)*sizeof (tchar))
348 		 */
349 		len = strlen_(cp);
350 		dp = (tchar *)xalloc((unsigned)(cwdlen + len + 2) * sizeof (tchar));
351 		for (p = dp, q = dcwd->di_name; *p++ = *q++; )
352 			;
353 		if (cwdlen)
354 			p[-1] = '/';
355 		else
356 			p--;			/* don't add a / after root */
357 		for (q = cp; *p++ = *q++; )
358 			;
359 		xfree(cp);
360 		cp = dp;
361 		dp += cwdlen;
362 	} else
363 		dp = cp;
364 	return dcanon(cp, dp);
365 }
366 
367 /*
368  * dopushd - push new directory onto directory stack.
369  *	with no arguments exchange top and second.
370  *	with numeric argument (+n) bring it to top.
371  */
372 void
373 dopushd(tchar **v)
374 {
375 	struct directory *dp;
376 
377 #ifdef TRACE
378 	tprintf("TRACE- dopushd()\n");
379 #endif
380 	printd = 1;
381 	if (*++v == NOSTR) {
382 		if ((dp = dcwd->di_prev) == &dhead)
383 			dp = dhead.di_prev;
384 		if (dp == dcwd)
385 			bferr("No other directory");
386 		if (chdir_(dp->di_name) < 0)
387 			Perror(dp->di_name);
388 		dp->di_prev->di_next = dp->di_next;
389 		dp->di_next->di_prev = dp->di_prev;
390 		dp->di_next = dcwd->di_next;
391 		dp->di_prev = dcwd;
392 		dcwd->di_next->di_prev = dp;
393 		dcwd->di_next = dp;
394 	} else if (dp = dfind(*v)) {
395 		if (chdir_(dp->di_name) < 0)
396 			Perror(dp->di_name);
397 	} else {
398 		tchar *cp;
399 
400 		cp = dfollow(*v);
401 		dp = (struct directory *)xcalloc(sizeof (struct directory), 1);
402 		dp->di_name = cp;
403 		dp->di_count = 0;
404 		dp->di_prev = dcwd;
405 		dp->di_next = dcwd->di_next;
406 		dcwd->di_next = dp;
407 		dp->di_next->di_prev = dp;
408 	}
409 	dnewcwd(dp);
410 }
411 
412 /*
413  * dfind - find a directory if specified by numeric (+n) argument
414  */
415 struct directory *
416 dfind(tchar *cp)
417 {
418 	struct directory *dp;
419 	int i;
420 	tchar *ep;
421 
422 #ifdef TRACE
423 	tprintf("TRACE- dfind()\n");
424 #endif
425 	if (*cp++ != '+')
426 		return (0);
427 	for (ep = cp; digit(*ep); ep++)
428 		continue;
429 	if (*ep)
430 		return (0);
431 	i = getn(cp);
432 	if (i <= 0)
433 		return (0);
434 	for (dp = dcwd; i != 0; i--) {
435 		if ((dp = dp->di_prev) == &dhead)
436 			dp = dp->di_prev;
437 		if (dp == dcwd)
438 			bferr("Directory stack not that deep");
439 	}
440 	return (dp);
441 }
442 
443 /*
444  * dopopd - pop a directory out of the directory stack
445  *	with a numeric argument just discard it.
446  */
447 void
448 dopopd(tchar **v)
449 {
450 	struct directory *dp, *p;
451 
452 #ifdef TRACE
453 	tprintf("TRACE- dopopd()\n");
454 #endif
455 	printd = 1;
456 	if (*++v == NOSTR)
457 		dp = dcwd;
458 	else if ((dp = dfind(*v)) == 0)
459 		bferr("Invalid argument");
460 	if (dp->di_prev == &dhead && dp->di_next == &dhead)
461 		bferr("Directory stack empty");
462 	if (dp == dcwd) {
463 		if ((p = dp->di_prev) == &dhead)
464 			p = dhead.di_prev;
465 		if (chdir_(p->di_name) < 0)
466 			Perror(p->di_name);
467 	}
468 	dp->di_prev->di_next = dp->di_next;
469 	dp->di_next->di_prev = dp->di_prev;
470 	if (dp == dcwd)
471 		dnewcwd(p);
472 	else
473 		dodirs(fakev);
474 	dfree(dp);
475 }
476 
477 /*
478  * dfree - free the directory (or keep it if it still has ref count)
479  */
480 void
481 dfree(struct directory *dp)
482 {
483 
484 #ifdef TRACE
485 	tprintf("TRACE- dfree()\n");
486 #endif
487 	if (dp->di_count != 0)
488 		dp->di_next = dp->di_prev = 0;
489 	else
490 		xfree(dp->di_name), xfree((tchar *)dp);
491 }
492 
493 /*
494  * dcanon - canonicalize the pathname, removing excess ./ and ../ etc.
495  *	We are of course assuming that the file system is standardly
496  *	constructed (always have ..'s, directories have links).
497  *
498  *	If the hardpaths shell variable is set, resolve the
499  *	resulting pathname to contain no symbolic link components.
500  */
501 tchar *
502 dcanon(tchar *cp, tchar *p)
503 {
504 	tchar *sp;	/* rightmost component currently under
505 				consideration */
506 	tchar *p1,	/* general purpose */
507 	    *p2;
508 	bool slash, dotdot, hardpaths;
509 
510 #ifdef TRACE
511 	tprintf("TRACE- dcannon()\n");
512 #endif
513 
514 	if (*cp != '/')
515 		abort();
516 
517 	if (hardpaths = (adrof(S_hardpaths) != NULL)) {
518 		/*
519 		 * Be paranoid: don't trust the initial prefix
520 		 * to be symlink-free.
521 		 */
522 		p = cp;
523 	}
524 
525 	/*
526 	 * Loop invariant: cp points to the overall path start,
527 	 * p to its as yet uncanonicalized trailing suffix.
528 	 */
529 	while (*p) {			/* for each component */
530 		sp = p;			/* save slash address */
531 
532 		while (*++p == '/')	/* flush extra slashes */
533 			;
534 		if (p != ++sp)
535 			for (p1 = sp, p2 = p; *p1++ = *p2++; )
536 				;
537 
538 		p = sp;			/* save start of component */
539 		slash = 0;
540 		if (*p)
541 			while (*++p)	/* find next slash or end of path */
542 				if (*p == '/') {
543 					slash = 1;
544 					*p = '\0';
545 					break;
546 				}
547 
548 		if (*sp == '\0') {
549 			/* component is null */
550 			if (--sp == cp)	/* if path is one tchar (i.e. /) */
551 				break;
552 			else
553 				*sp = '\0';
554 			continue;
555 		}
556 
557 		if (sp[0] == '.' && sp[1] == '\0') {
558 			/* Squeeze out component consisting of "." */
559 			if (slash) {
560 				for (p1 = sp, p2 = p + 1; *p1++ = *p2++; )
561 					;
562 				p = --sp;
563 			} else if (--sp != cp)
564 				*sp = '\0';
565 			continue;
566 		}
567 
568 		/*
569 		 * At this point we have a path of the form "x/yz",
570 		 * where "x" is null or rooted at "/", "y" is a single
571 		 * component, and "z" is possibly null.  The pointer cp
572 		 * points to the start of "x", sp to the start of "y",
573 		 * and p to the beginning of "z", which has been forced
574 		 * to a null.
575 		 */
576 		/*
577 		 * Process symbolic link component.  Provided that either
578 		 * the hardpaths shell variable is set or "y" is really
579 		 * ".." we replace the symlink with its contents.  The
580 		 * second condition for replacement is necessary to make
581 		 * the command "cd x/.." produce the same results as the
582 		 * sequence "cd x; cd ..".
583 		 *
584 		 * Note that the two conditions correspond to different
585 		 * potential symlinks.  When hardpaths is set, we must
586 		 * check "x/y"; otherwise, when "y" is known to be "..",
587 		 * we check "x".
588 		 */
589 		dotdot = sp[0] == '.' && sp[1] == '.' && sp[2] == '\0';
590 		if (hardpaths || dotdot) {
591 			tchar link[MAXPATHLEN];
592 			int cc;
593 			tchar *newcp;
594 
595 			/*
596 			 * Isolate the end of the component that is to
597 			 * be checked for symlink-hood.
598 			 */
599 			sp--;
600 			if (! hardpaths)
601 				*sp = '\0';
602 
603 			/*
604 			 * See whether the component is really a symlink by
605 			 * trying to read it.  If the read succeeds, it is.
606 			 */
607 			if ((hardpaths || sp > cp) &&
608 			    (cc = readlink_(cp, link, MAXPATHLEN)) >= 0) {
609 				/*
610 				 * readlink_ put null, so we don't need this.
611 				 */
612 				/* link[cc] = '\0'; */
613 
614 				/* Restore path. */
615 				if (slash)
616 					*p = '/';
617 
618 				/*
619 				 * Point p at the start of the trailing
620 				 * path following the symlink component.
621 				 * It's already there is hardpaths is set.
622 				 */
623 				if (! hardpaths) {
624 					/* Restore path as well. */
625 					*(p = sp) = '/';
626 				}
627 
628 				/*
629 				 * Find length of p.
630 				 */
631 				for (p1 = p; *p1++; )
632 					;
633 
634 				if (*link != '/') {
635 					/*
636 					 * Relative path: replace the symlink
637 					 * component with its value.  First,
638 					 * set sp to point to the slash at
639 					 * its beginning.  If hardpaths is
640 					 * set, this is already the case.
641 					 */
642 					if (! hardpaths) {
643 						while (*--sp != '/')
644 							;
645 					}
646 
647 					/*
648 					 * Terminate the leading part of the
649 					 * path, including trailing slash.
650 					 */
651 					sp++;
652 					*sp = '\0';
653 
654 					/*
655 					 * New length is: "x/" + link + "z"
656 					 */
657 					p1 = newcp = (tchar *)xalloc((unsigned)
658 						((sp - cp) + cc + (p1 - p)) * sizeof (tchar));
659 					/*
660 					 * Copy new path into newcp
661 					 */
662 					for (p2 = cp; *p1++ = *p2++; )
663 						;
664 					for (p1--, p2 = link; *p1++ = *p2++; )
665 						;
666 					for (p1--, p2 = p; *p1++ = *p2++; )
667 						;
668 					/*
669 					 * Restart canonicalization at
670 					 * expanded "/y".
671 					 */
672 					p = sp - cp - 1 + newcp;
673 				} else {
674 					/*
675 					 * New length is: link + "z"
676 					 */
677 					p1 = newcp = (tchar *)xalloc((unsigned)
678 						(cc + (p1 - p))*sizeof (tchar));
679 					/*
680 					 * Copy new path into newcp
681 					 */
682 					for (p2 = link; *p1++ = *p2++; )
683 						;
684 					for (p1--, p2 = p; *p1++ = *p2++; )
685 						;
686 					/*
687 					 * Restart canonicalization at beginning
688 					 */
689 					p = newcp;
690 				}
691 				xfree(cp);
692 				cp = newcp;
693 				continue;	/* canonicalize the link */
694 			}
695 
696 			/* The component wasn't a symlink after all. */
697 			if (! hardpaths)
698 				*sp = '/';
699 		}
700 
701 		if (dotdot) {
702 			if (sp != cp)
703 				while (*--sp != '/')
704 					;
705 			if (slash) {
706 				for (p1 = sp + 1, p2 = p + 1; *p1++ = *p2++; )
707 					;
708 				p = sp;
709 			} else if (cp == sp)
710 				*++sp = '\0';
711 			else
712 				*sp = '\0';
713 			continue;
714 		}
715 
716 		if (slash)
717 			*p = '/';
718 	}
719 	return cp;
720 }
721 
722 /*
723  * dnewcwd - make a new directory in the loop the current one
724  *	and export its name to the PWD environment variable.
725  */
726 void
727 dnewcwd(struct directory *dp)
728 {
729 
730 #ifdef TRACE
731 	tprintf("TRACE- dnewcwd()\n");
732 #endif
733 	dcwd = dp;
734 #ifdef notdef
735 	/*
736 	 * If we have a fast version of getwd available
737 	 * and hardpaths is set, it would be reasonable
738 	 * here to verify that dcwd->di_name really does
739 	 * name the current directory.  Later...
740 	 */
741 #endif /* notdef */
742 
743 	didchdir = 1;
744 	set(S_cwd, savestr(dcwd->di_name));
745 	didchdir = 0;
746 	local_setenv(S_PWD, dcwd->di_name);
747 	if (printd)
748 		dodirs(fakev);
749 }
750