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 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1988 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * _xftw - file tree walk the uses expanded stat structure
32 *
33 * int _xftw(path, fn, depth) char *path; int (*fn)(); int depth;
34 *
35 * Given a path name, _xftw starts from the file given by that path
36 * name and visits each file and directory in the tree beneath
37 * that file. If a single file has multiple links within the
38 * structure, it will be visited once for each such link.
39 * For each object visited, fn is called with three arguments.
40 * (*fn) (pathname, statp, ftwflag)
41 * The first contains the path name of the object, the second
42 * contains a pointer to a stat buffer which will usually hold
43 * appropriate information for the object and the third will
44 * contain an integer value giving additional information about
45 *
46 * FTW_F The object is a file for which stat was
47 * successful. It does not guarantee that the
48 * file can actually be read.
49 *
50 * FTW_D The object is a directory for which stat and
51 * open for read were both successful.
52 *
53 * FTW_DNR The object is a directory for which stat
54 * succeeded, but which cannot be read. Because
55 * the directory cannot be read, fn will not be
56 * called for any descendants of this directory.
57 *
58 * FTW_NS Stat failed on the object because of lack of
59 * appropriate permission. This indication will
60 * be given for example for each file in a
61 * directory with read but no execute permission.
62 * Because stat failed, it is not possible to
63 * determine whether this object is a file or a
64 * directory. The stat buffer passed to fn will
65 * contain garbage. Stat failure for any reason
66 * other than lack of permission will be
67 * considered an error and will cause _xftw to stop
68 * and return -1 to its caller.
69 *
70 * If fn returns nonzero, _xftw stops and returns the same value
71 * to its caller. If _xftw gets into other trouble along the way,
72 * it returns -1 and leaves an indication of the cause in errno.
73 *
74 * The third argument to _xftw does not limit the depth to which
75 * _xftw will go. Rather, it limits the depth to which _xftw will
76 * go before it starts recycling file descriptors. In general,
77 * it is necessary to use a file descriptor for each level of the
78 * tree, but they can be recycled for deep trees by saving the
79 * position, closing, re-opening, and seeking. In order to descend
80 * to arbitrary depths, _xftw requires 2 file descriptors to be open
81 * during the call to openat(), therefore if the depth argument
82 * is less than 2 _xftw will not use openat(), and it will fail with
83 * ENAMETOOLONG if it descends to a directory that exceeds PATH_MAX.
84 */
85
86 /*
87 * this interface uses the expanded stat structure and therefore
88 * must have EFT enabled.
89 */
90 #ifdef _STYPES
91 #undef _STYPES
92 #endif
93
94 #include "lint.h"
95 #include <sys/types.h>
96 #include <sys/stat.h>
97 #include <fcntl.h>
98 #include <sys/param.h>
99 #include <dirent.h>
100 #include <errno.h>
101 #include <ftw.h>
102 #include <string.h>
103 #include <stdlib.h>
104 #include <unistd.h>
105
106 struct Var {
107 int level;
108 int odepth;
109 };
110
111 static DIR *nocdopendir(const char *, struct Var *);
112 static int nocdstat(const char *, struct stat *, struct Var *, int);
113 static const char *get_unrooted(const char *);
114 static int fwalk(const char *, int (*)(const char *, const struct stat *, int),
115 int, struct Var *);
116
117 int
_xftw(int ver __unused,const char * path,int (* fn)(const char *,const struct stat *,int),int depth)118 _xftw(int ver __unused, const char *path,
119 int (*fn)(const char *, const struct stat *, int), int depth)
120 {
121 struct Var var;
122 int rc;
123
124 var.level = 0;
125 var.odepth = depth;
126 rc = fwalk(path, fn, depth, &var);
127 return (rc);
128 }
129
130 /*
131 * This is the recursive walker.
132 */
133 static int
fwalk(const char * path,int (* fn)(const char *,const struct stat *,int),int depth,struct Var * vp)134 fwalk(const char *path, int (*fn)(const char *, const struct stat *, int),
135 int depth, struct Var *vp)
136 {
137 size_t n;
138 int rc;
139 int save_errno;
140 DIR *dirp;
141 char *subpath;
142 struct stat sb;
143 struct dirent *direntp;
144
145 vp->level++;
146
147 /*
148 * Try to get file status.
149 * If unsuccessful, errno will say why.
150 * It's ok to have a symbolic link that points to
151 * non-existing file. In this case, pass FTW_NS
152 * to a function instead of aborting fwalk() right away.
153 */
154 if (nocdstat(path, &sb, vp, 0) < 0) {
155 #ifdef S_IFLNK
156 save_errno = errno;
157 if ((nocdstat(path, &sb, vp, AT_SYMLINK_NOFOLLOW) != -1) &&
158 ((sb.st_mode & S_IFMT) == S_IFLNK)) {
159 errno = save_errno;
160 return (*fn)(path, &sb, FTW_NS);
161 } else {
162 errno = save_errno;
163 }
164 #endif
165 return (errno == EACCES? (*fn)(path, &sb, FTW_NS): -1);
166 }
167
168 /*
169 * The stat succeeded, so we know the object exists.
170 * If not a directory, call the user function and return.
171 */
172 if ((sb.st_mode & S_IFMT) != S_IFDIR)
173 return ((*fn)(path, &sb, FTW_F));
174
175 /*
176 * The object was a directory.
177 *
178 * Open a file to read the directory
179 */
180 dirp = nocdopendir(path, vp);
181
182 /*
183 * Call the user function, telling it whether
184 * the directory can be read. If it can't be read
185 * call the user function or indicate an error,
186 * depending on the reason it couldn't be read.
187 */
188 if (dirp == NULL)
189 return (errno == EACCES? (*fn)(path, &sb, FTW_DNR): -1);
190
191 /* We could read the directory. Call user function. */
192 rc = (*fn)(path, &sb, FTW_D);
193 if (rc != 0) {
194 (void) closedir(dirp);
195 return (rc);
196 }
197
198 /*
199 * Read the directory one component at a time.
200 * We must ignore "." and "..", but other than that,
201 * just create a path name and call self to check it out.
202 */
203 while ((direntp = readdir(dirp)) != NULL) {
204 long here;
205
206 if (strcmp(direntp->d_name, ".") == 0 ||
207 strcmp(direntp->d_name, "..") == 0)
208 continue;
209
210 /* Create a prefix to which we will append component names */
211 n = strlen(path);
212 subpath = malloc(n + strlen(direntp->d_name) + 2);
213 if (subpath == 0) {
214 (void) closedir(dirp);
215 errno = ENOMEM;
216 return (-1);
217 }
218 (void) strcpy(subpath, path);
219 if (subpath[0] != '\0' && subpath[n-1] != '/')
220 subpath[n++] = '/';
221
222 /* Append component name to the working path */
223 (void) strlcpy(&subpath[n], direntp->d_name, MAXNAMELEN);
224
225 /*
226 * If we are about to exceed our depth,
227 * remember where we are and close a file.
228 */
229 if (depth <= 1) {
230 here = telldir(dirp);
231 if (closedir(dirp) < 0) {
232 free(subpath);
233 return (-1);
234 }
235 }
236
237 /*
238 * Do a recursive call to process the file.
239 * (watch this, sports fans)
240 */
241 rc = fwalk(subpath, fn, depth-1, vp);
242 if (rc != 0) {
243 free(subpath);
244 if (depth > 1)
245 (void) closedir(dirp);
246 return (rc);
247 }
248
249 /*
250 * If we closed the file, try to reopen it.
251 */
252 if (depth <= 1) {
253 dirp = nocdopendir(path, vp);
254 if (dirp == NULL) {
255 free(subpath);
256 return (-1);
257 }
258 seekdir(dirp, here);
259 }
260 free(subpath);
261 }
262 (void) closedir(dirp);
263 return (0);
264 }
265
266 /*
267 * Open a directory with an arbitrarily long path name. If the original
268 * depth arg >= 2, use openat() to make sure that it doesn't fail with
269 * ENAMETOOLONG.
270 */
271 static DIR *
nocdopendir(const char * path,struct Var * vp)272 nocdopendir(const char *path, struct Var *vp)
273 {
274 int fd, cfd;
275 DIR *fdd;
276 char *dirp, *token, *ptr;
277
278 fdd = opendir(path);
279 if ((vp->odepth > 1) && (fdd == NULL) && (errno == ENAMETOOLONG)) {
280 /*
281 * Traverse the path using openat() to get the fd for
282 * fdopendir().
283 */
284 if ((dirp = strdup(path)) == NULL) {
285 errno = ENAMETOOLONG;
286 return (NULL);
287 }
288 if ((token = strtok_r(dirp, "/", &ptr)) != NULL) {
289 if ((fd = openat(AT_FDCWD, dirp, O_RDONLY)) < 0) {
290 (void) free(dirp);
291 errno = ENAMETOOLONG;
292 return (NULL);
293 }
294 while ((token = strtok_r(NULL, "/", &ptr)) != NULL) {
295 if ((cfd = openat(fd, token, O_RDONLY)) < 0) {
296 (void) close(fd);
297 (void) free(dirp);
298 errno = ENAMETOOLONG;
299 return (NULL);
300 }
301 (void) close(fd);
302 fd = cfd;
303 }
304 (void) free(dirp);
305 return (fdopendir(fd));
306 }
307 (void) free(dirp);
308 errno = ENAMETOOLONG;
309 }
310 return (fdd);
311 }
312
313 /*
314 * Stat a file with an arbitrarily long path name. If we aren't doing a
315 * stat on the arg passed to _xftw() and if the original depth arg >= 2,
316 * use openat() to make sure that it doesn't fail with ENAMETOOLONG.
317 */
318 static int
nocdstat(const char * path,struct stat * statp,struct Var * vp,int sym)319 nocdstat(const char *path, struct stat *statp, struct Var *vp, int sym)
320 {
321 int fd, cfd;
322 char *dirp, *token, *ptr;
323 int rc;
324 const char *unrootp;
325 int save_err;
326
327 rc = fstatat(AT_FDCWD, path, statp, sym);
328 if ((vp->level > 1) && (vp->odepth >= 2) && (rc < 0) &&
329 (errno == ENAMETOOLONG)) {
330 /* Traverse path using openat() to get fd for fstatat(). */
331 if ((dirp = strdup(path)) == NULL) {
332 errno = ENAMETOOLONG;
333 return (-1);
334 }
335 if ((token = strtok_r(dirp, "/", &ptr)) != NULL) {
336 if ((fd = openat(AT_FDCWD, dirp, O_RDONLY)) < 0) {
337 (void) free(dirp);
338 errno = ENAMETOOLONG;
339 return (-1);
340 }
341 unrootp = get_unrooted(path);
342 while (((token = strtok_r(NULL, "/", &ptr)) != NULL) &&
343 (strcmp(token, unrootp) != 0)) {
344 if ((cfd = openat(fd, token, O_RDONLY)) < 0) {
345 (void) close(fd);
346 (void) free(dirp);
347 errno = ENAMETOOLONG;
348 return (0);
349 }
350 (void) close(fd);
351 fd = cfd;
352 }
353 (void) free(dirp);
354 rc = fstatat(fd, unrootp, statp, sym);
355 save_err = errno;
356 (void) close(fd);
357 errno = save_err;
358 return (rc);
359 }
360 (void) free(dirp);
361 errno = ENAMETOOLONG;
362 }
363 return (rc);
364 }
365
366 /*
367 * Return pointer basename of path. This routine doesn't remove
368 * trailing slashes, but there won't be any.
369 */
370 static const char *
get_unrooted(const char * path)371 get_unrooted(const char *path)
372 {
373 const char *ptr;
374
375 if (!path || !*path)
376 return (NULL);
377
378 ptr = path + strlen(path);
379 /* find last char in path before any trailing slashes */
380 while (ptr != path && *--ptr == '/')
381 ;
382
383 if (ptr == path) /* all slashes */
384 return (ptr);
385
386 while (ptr != path)
387 if (*--ptr == '/')
388 return (++ptr);
389
390 return (ptr);
391 }
392