xref: /illumos-gate/usr/src/lib/libinstzones/common/zones_paths.c (revision af1222373b60d56d6b0e630911372d4162b7787b)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 
28 
29 /*
30  * System includes
31  */
32 
33 #include <stdio.h>
34 #include <limits.h>
35 #include <stdlib.h>
36 #include <unistd.h>
37 #include <libgen.h>
38 #include <errno.h>
39 #include <string.h>
40 #include <fcntl.h>
41 #include <sys/types.h>
42 #include <sys/stat.h>
43 #include <signal.h>
44 #include <assert.h>
45 #include <locale.h>
46 #include <libintl.h>
47 
48 /*
49  * local includes
50  */
51 
52 #include "instzones_lib.h"
53 #include "zones_strings.h"
54 
55 #define	isdot(x)	((x[0] == '.') && (!x[1] || (x[1] == '/')))
56 #define	isdotdot(x)	((x[0] == '.') && (x[1] == '.') && \
57 		    (!x[2] || (x[2] == '/')))
58 
59 /*
60  * forward declarations
61  */
62 
63 static char		**inheritedFileSystems = (char **)NULL;
64 static size_t		*inheritedFileSystemsLen = (size_t *)NULL;
65 static int		numInheritedFileSystems = 0;
66 
67 /*
68  * *****************************************************************************
69  * global external (public) functions
70  * *****************************************************************************
71  */
72 
73 /*
74  * Name:	z_get_inherited_file_systems
75  * Description:	Return list of file systems inherited from the global zone;
76  *		These file systems are entered into the list when the function
77  *		pkgAddInheritedFileSystem() is called.
78  * Arguments:	void
79  * Returns:	char **
80  *			- pointer to array of character pointers, each pointer
81  *			being a pointer to a string representing a file
82  *			system that is inherited from the global zone
83  *			the last entry will be (char *)NULL
84  *			- (char **)NULL - no file systems inherited
85  *
86  */
87 
88 char **
89 z_get_inherited_file_systems(void)
90 {
91 	return (inheritedFileSystems);
92 }
93 
94 /*
95  * Name:	z_add_inherited_file_system
96  * Description:	Add specified package to internal list of inherited file systems
97  * Arguments:	a_inheritedFileSystem - absolute path to file systen "inherited"
98  *
99  *		This function is called to register a directory (or
100  *		file system) as being inherited from the global zone
101  *		into the non-global zone being operated on.  The
102  *		inherited directory must be specified relative to the
103  *		root file system ("/").  For example, if "/usr" is
104  *		inherited, then the path specified would be "/usr".
105  *
106  *		Any path subsequently checked for being present in a
107  *		directory inherited read-only from the global zone:
108  *
109  *		-- will NOT have $PKG_INSTALL_ROOT prepended to it
110  *		-- if $PKG_INSTALL_ROOT is set and $BASEDIR is not set.
111  *		-- WILL have $BASEDIR prepended to it (if set).
112  *		-- $BASEDIR always has $PKG_INSTALL_ROOT included in it.
113  *		-- For example, if $PKG_INSTALL_ROOT is set to /a, and
114  *		-- the base install directory is set to "/opt", then the
115  *		-- $BASEDIR variable will be set to "/a/opt".
116  *
117  *		Any path that is checked for being present in an inherited
118  *		directory will be specified relative to the root file system
119  *		of the non-global zone in which the path is located.
120  *
121  *		When a path to update is checked for being present in
122  *		an inherited directory, $PKG_INSTALL_ROOT is stripped
123  *		off the path before it is checked.
124  *
125  *		If the non-global zone is not running, the scratch zone
126  *		is used to access the non-global zone.  In this case,
127  *		$PKG_INSTALL_ROOT will be set to "/a" and both the
128  *		non-global zone's root file system and all inherited
129  *		directories will be mounted on "/a". When a path is checked
130  *		for being inherited, it will have $PKG_INSTALL_ROOT stripped
131  *		from the beginning, so any inherited directories must be
132  *		specified relative to "/" and not $PKG_INSTALL_ROOT.
133  *
134  *		If the non-global zone is running, the non-global zone
135  *		is used directly. In this case, $PKG_INSTALL_ROOT will
136  *		be set to "/" and both the non-global zone's root file
137  *		system and all inherited directories will be mounted on
138  *		"/". $PKG_INSTALL_ROOT is set to "/" so the path is unchanged
139  *		before being checked against the list of inherited directories.
140  *
141  * Returns:	boolean_t
142  *			B_TRUE - file system successfully added to list
143  *			B_FALSE - failed to add file system to list
144  */
145 
146 boolean_t
147 z_add_inherited_file_system(char *a_inheritedFileSystem)
148 {
149 #define	IPSLOP	2		/* for trailing '/' and '\0' */
150 #define	IPMAX	((sizeof (rp))-IPSLOP)
151 
152 	char	rp[PATH_MAX+1+IPSLOP] = {'\0'};
153 	int	n;
154 
155 	/* file system cannot be empty */
156 
157 	if (a_inheritedFileSystem == NULL || *a_inheritedFileSystem == '\0') {
158 		_z_program_error(ERR_INHERITED_PATH_NULL);
159 		return (B_FALSE);
160 	}
161 
162 	/* file system must be absolute */
163 
164 	if (*a_inheritedFileSystem != '/') {
165 		_z_program_error(ERR_INHERITED_PATH_NOT_ABSOLUTE,
166 		    a_inheritedFileSystem);
167 		return (B_FALSE);
168 	}
169 
170 	/* make a local copy of the path and canonize it */
171 
172 	n = strlcpy(rp, a_inheritedFileSystem, IPMAX);
173 	if (n > IPMAX) {
174 		_z_program_error(ERR_INHERITED_PATH_TOO_LONG,
175 		    strlen(a_inheritedFileSystem), IPMAX,
176 		    a_inheritedFileSystem);
177 		return (B_FALSE);
178 	}
179 
180 	assert(n > 0);	/* path must have at least 1 byte in it */
181 
182 	z_path_canonize(rp);	/* remove duplicate "/"s, ./, etc */
183 
184 	/* add trailing "/" if it's not already there */
185 	n = strlen(rp);
186 	if (rp[n-1] != '/') {
187 		rp[n++] = '/';
188 	}
189 
190 	/* null terminate the string */
191 
192 	rp[n] = '\0';
193 
194 	/* add file system to internal list */
195 
196 	if (inheritedFileSystems == (char **)NULL) {
197 		inheritedFileSystems = (char **)_z_calloc(
198 		    2 * (sizeof (char **)));
199 		inheritedFileSystemsLen =
200 		    (size_t *)_z_calloc(2 * (sizeof (size_t *)));
201 	} else {
202 		inheritedFileSystems = (char **)_z_realloc(inheritedFileSystems,
203 		    sizeof (char **)*(numInheritedFileSystems+2));
204 		inheritedFileSystemsLen = (size_t *)_z_realloc(
205 		    inheritedFileSystemsLen,
206 		    sizeof (size_t *)*(numInheritedFileSystems+2));
207 	}
208 
209 	/* add this entry to the end of the list */
210 
211 	inheritedFileSystemsLen[numInheritedFileSystems] = strlen(rp);
212 	inheritedFileSystems[numInheritedFileSystems] = _z_strdup(rp);
213 
214 	numInheritedFileSystems++;
215 
216 	/* make sure end of the list is properly terminated */
217 
218 	inheritedFileSystemsLen[numInheritedFileSystems] = 0;
219 	inheritedFileSystems[numInheritedFileSystems] = (char *)NULL;
220 
221 	/* exit debugging info */
222 
223 	_z_echoDebug(DBG_PATHS_ADD_FS, numInheritedFileSystems,
224 	    inheritedFileSystems[numInheritedFileSystems-1]);
225 
226 	return (B_TRUE);
227 }
228 
229 /*
230  * Name:	z_path_is_inherited
231  * Description:	Determine if the specified path is in a file system that is
232  *		in the internal list of inherited file systems
233  * Arguments:	a_path - pointer to string representing path to verify
234  *		a_ftype - file "type" if known otherwise '\0'
235  *			Type can be "f" (file), or "d" (directory)
236  *		a_rootDir - pointer to string representing root directory where
237  *			a_path is relative to - typically this would either be
238  *			"/" or the path specified as an alternative root to -R
239  * Returns:	boolean_t
240  *			B_TRUE - the path is in inherited file system space
241  *			B_FALSE - the path is NOT in inherited file system space
242  */
243 
244 boolean_t
245 z_path_is_inherited(char *a_path, char a_ftype, char *a_rootDir)
246 {
247 	int	n;
248 	char	*cp, *path2use;
249 	char	real_path[PATH_MAX];
250 	char	path_copy[PATH_MAX];
251 	boolean_t found = B_FALSE;
252 
253 	/* entry assertions */
254 
255 	assert(a_path != (char *)NULL);
256 	assert(*a_path != '\0');
257 
258 	/* if no inherited file systems, there can be no match */
259 
260 	if (numInheritedFileSystems == 0) {
261 		_z_echoDebug(DBG_PATHS_NOT_INHERITED, a_path);
262 		return (B_FALSE);
263 	}
264 
265 	/* normalize root directory */
266 
267 	if ((a_rootDir == (char *)NULL) || (*a_rootDir == '\0')) {
268 		a_rootDir = "/";
269 	}
270 
271 	/*
272 	 * The loop below represents our best effort to identify real path of
273 	 * a file, which doesn't need to exist. realpath() returns error for
274 	 * nonexistent path, therefore we need to cut off trailing components
275 	 * of path until we get path which exists and can be resolved by
276 	 * realpath(). Lookup of "/dir/symlink/nonexistent-file" would fail
277 	 * to resolve symlink without this.
278 	 */
279 	(void) strlcpy(path_copy, a_path, PATH_MAX);
280 	for (cp = dirname(path_copy); strlen(cp) > 1; cp = dirname(cp)) {
281 		if (realpath(cp, real_path) != NULL) {
282 			found = B_TRUE;
283 			break;
284 		} else if (errno != ENOENT)
285 			break;
286 	}
287 	if (found) {
288 		/*
289 		 * In the loop above we always strip trailing path component,
290 		 * so the type of real_path is always 'd'.
291 		 */
292 		a_ftype = 'd';
293 		path2use = real_path;
294 	} else {
295 		path2use = a_path;
296 	}
297 
298 	/*
299 	 * if path resides on an inherited filesystem then
300 	 * it must be read-only.
301 	 */
302 
303 	if (z_isPathWritable(path2use) != 0) {
304 		return (B_FALSE);
305 	}
306 
307 	/*
308 	 * remove the root path from the target path before comparing:
309 	 * Example 1:
310 	 * -- path is "/export/zone1/root/usr/test"
311 	 * -- root path is "/export/zone1/root"
312 	 * --- final path should be "/usr/test"
313 	 * Example 2:
314 	 * -- path is "/usr/test"
315 	 * -- root path is "/"
316 	 * --- final path should be "/usr/test"
317 	 */
318 
319 	/* advance past given root directory if path begins with it */
320 
321 	n = strlen(a_rootDir);
322 	if (strncmp(a_rootDir, path2use, n) == 0) {
323 		char	*p;
324 
325 		/* advance past the root path */
326 
327 		p = path2use + n;
328 
329 		/* go back to the first occurance of the path separator */
330 
331 		while ((*p != '/') && (p > path2use)) {
332 			p--;
333 		}
334 
335 		/* use this location in the path to compare */
336 
337 		path2use = p;
338 	}
339 
340 	/*
341 	 * see if this path is in any inherited file system path
342 	 * note that all paths in the inherited list are directories
343 	 * so they end in "/" to prevent a partial match, such as
344 	 * comparing "/usr/libx" with "/usr/lib" - by making the comparison
345 	 * "/usr/libx" with "/usr/lib/" the partial false positive will not
346 	 * occur. This complicates matters when the object to compare is a
347 	 * directory - in this case, comparing "/usr" with "/usr/" will fail,
348 	 * so if the object is a directory, compare one less byte from the
349 	 * inherited file system so that the trailing "/" is ignored.
350 	 */
351 
352 	for (n = 0; n < numInheritedFileSystems; n++) {
353 		int	fslen;
354 
355 		/* get target fs len; adjust -1 if directory */
356 
357 		fslen = inheritedFileSystemsLen[n];
358 		if ((a_ftype == 'd') && (fslen > 1)) {
359 			fslen--;
360 		}
361 
362 		if (strncmp(path2use, inheritedFileSystems[n], fslen) == 0) {
363 			_z_echoDebug(DBG_PATHS_IS_INHERITED, a_path,
364 			    inheritedFileSystems[n]);
365 			return (B_TRUE);
366 		}
367 	}
368 
369 	/* path is not in inherited file system space */
370 
371 	_z_echoDebug(DBG_PATHS_IS_NOT_INHERITED, a_path, a_rootDir);
372 
373 	return (B_FALSE);
374 }
375 
376 /*
377  * Name:	z_make_zone_root
378  * Description:	Given its zonepath, generate a string representing the
379  *              mountpoint of where the root path for a nonglobal zone is
380  *              mounted.  The zone is mounted using 'zoneadm', which mounts
381  *              the zone's filesystems wrt <zonepath>/lu/a
382  * Arguments:	zone_path - non-NULL pointer to string representing zonepath
383  * Returns:	char *	- pointer to string representing zonepath of zone
384  *		NULL	- if zone_path is NULL.
385  * Notes:	The string returned is in static storage and should not be
386  *              free()ed by the caller.
387  */
388 char *
389 z_make_zone_root(char *zone_path)
390 {
391 	static char	zone_root_buf[MAXPATHLEN];
392 
393 	if (zone_path == NULL)
394 		return (NULL);
395 
396 	(void) snprintf(zone_root_buf, MAXPATHLEN, "%s%slu/a", zone_path,
397 	    (zone_path[0] != '\0' &&
398 	    zone_path[strlen(zone_path) - 1] == '/') ? "" : "/");
399 
400 	return (zone_root_buf);
401 }
402 
403 void
404 z_path_canonize(char *a_file)
405 {
406 	char	*pt;
407 	char	*last;
408 	int	level;
409 
410 	/* remove references such as "./" and "../" and "//" */
411 	for (pt = a_file; *pt; /* void */) {
412 		if (isdot(pt)) {
413 			(void) strcpy(pt, pt[1] ? pt+2 : pt+1);
414 		} else if (isdotdot(pt)) {
415 			level = 0;
416 			last = pt;
417 			do {
418 				level++;
419 				last += 2;
420 				if (*last) {
421 					last++;
422 				}
423 			} while (isdotdot(last));
424 			--pt; /* point to previous '/' */
425 			while (level--) {
426 				if (pt <= a_file) {
427 					return;
428 				}
429 				while ((*--pt != '/') && (pt > a_file))
430 					;
431 			}
432 			if (*pt == '/') {
433 				pt++;
434 			}
435 			(void) strcpy(pt, last);
436 		} else {
437 			while (*pt && (*pt != '/')) {
438 				pt++;
439 			}
440 			if (*pt == '/') {
441 				while (pt[1] == '/') {
442 					(void) strcpy(pt, pt+1);
443 				}
444 				pt++;
445 			}
446 		}
447 	}
448 
449 	if ((--pt > a_file) && (*pt == '/')) {
450 		*pt = '\0';
451 	}
452 }
453 
454 void
455 z_canoninplace(char *src)
456 {
457 	char *dst;
458 	char *src_start;
459 
460 	/* keep a ptr to the beginning of the src string */
461 	src_start = src;
462 
463 	dst = src;
464 	while (*src) {
465 		if (*src == '/') {
466 			*dst++ = '/';
467 			while (*src == '/')
468 				src++;
469 		} else
470 			*dst++ = *src++;
471 	}
472 
473 	/*
474 	 * remove any trailing slashes, unless the whole string is just "/".
475 	 * If the whole string is "/" (i.e. if the last '/' cahr in dst
476 	 * in the beginning of the original string), just terminate it
477 	 * and return "/".
478 	 */
479 	if ((*(dst - 1) == '/') && ((dst - 1) != src_start))
480 		dst--;
481 	*dst = '\0';
482 }
483 
484 void
485 z_free_inherited_file_systems(void)
486 {
487 	int i;
488 
489 	for (i = 0; i < numInheritedFileSystems; i++) {
490 		free(inheritedFileSystems[i]);
491 	}
492 	free(inheritedFileSystems);
493 	inheritedFileSystems = NULL;
494 	free(inheritedFileSystemsLen);
495 	inheritedFileSystemsLen = NULL;
496 	numInheritedFileSystems = 0;
497 }
498