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 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /* Copyright (c) 1988 AT&T */
27 /* All Rights Reserved */
28
29 #pragma ident "%Z%%M% %I% %E% SMI"
30
31 /* LINTLIBRARY */
32 /*
33 * ftw - file tree walk
34 *
35 * int ftw (path, fn, depth) char *path; int (*fn)(); int depth;
36 *
37 * Given a path name, ftw starts from the file given by that path
38 * name and visits each file and directory in the tree beneath
39 * that file. If a single file has multiple links within the
40 * structure, it will be visited once for each such link.
41 * For each object visited, fn is called with three arguments.
42 * The first contains the path name of the object, the second
43 * contains a pointer to a stat buffer which will usually hold
44 * appropriate information for the object and the third will
45 * contain an integer value giving additional information:
46 *
47 * FTW_F The object is a file for which stat was
48 * successful. It does not guarantee that the
49 * file can actually be read.
50 *
51 * FTW_D The object is a directory for which stat and
52 * open for read were both successful.
53 *
54 * FTW_DNR The object is a directory for which stat
55 * succeeded, but which cannot be read. Because
56 * the directory cannot be read, fn will not be
57 * called for any descendants of this directory.
58 *
59 * FTW_NS Stat failed on the object because of lack of
60 * appropriate permission. This indication will
61 * be given, for example, for each file in a
62 * directory with read but no execute permission.
63 * Because stat failed, it is not possible to
64 * determine whether this object is a file or a
65 * directory. The stat buffer passed to fn will
66 * contain garbage. Stat failure for any reason
67 * other than lack of permission will be
68 * considered an error and will cause ftw to stop
69 * and return -1 to its caller.
70 *
71 * If fn returns nonzero, ftw stops and returns the same value
72 * to its caller. If ftw gets into other trouble along the way,
73 * it returns -1 and leaves an indication of the cause in errno.
74 *
75 * The third argument to ftw does not limit the depth to which
76 * ftw will go. Rather, it limits the depth to which ftw will
77 * go before it starts recycling file descriptors. In general,
78 * it is necessary to use a file descriptor for each level of the
79 * tree, but they can be recycled for deep trees by saving the
80 * position, closing, re-opening, and seeking. It is possible
81 * to start recycling file descriptors by sensing when we have
82 * run out, but in general this will not be terribly useful if
83 * fn expects to be able to open files. We could also figure out
84 * how many file descriptors are available and guarantee a certain
85 * number to fn, but we would not know how many to guarantee,
86 * and we do not want to impose the extra overhead on a caller who
87 * knows how many are available without having to figure it out.
88 *
89 * It is possible for ftw to die with a memory fault in the event
90 * of a file system so deeply nested that the stack overflows.
91 */
92
93 #include <sys/fs/ufs_inode.h>
94 #include <sys/types.h>
95 #include <sys/stat.h>
96 #include <dirent.h>
97 #include <errno.h>
98 #include <malloc.h>
99 #include <string.h>
100 #include <fcntl.h>
101 #include <unistd.h>
102 #include <ftw.h>
103
104 #define NULL 0
105
106 static int pwdfd;
107
108 static int lf_xftw(
109 const char *,
110 int (*)(const char *, const struct stat64 *, int),
111 int,
112 int (*)(const char *, struct stat64 *));
113
114 int
lf_lftw(const char * path,int (* fn)(const char *,const struct stat64 *,int),int depth)115 lf_lftw(
116 const char *path,
117 int (*fn)(const char *, const struct stat64 *, int),
118 int depth)
119 {
120 int rc;
121
122 if ((pwdfd = open(".", O_RDONLY)) < 0) {
123 return (-1);
124 } else {
125 rc = (lf_xftw(path, fn, depth, lstat64));
126 (void) close(pwdfd);
127 return (rc);
128 }
129 }
130
131 static int
132 #ifdef __STDC__
lf_xftw(const char * path,int (* fn)(const char *,const struct stat64 *,int),int depth,int (* statfn)(const char *,struct stat64 *))133 lf_xftw(
134 const char *path,
135 int (*fn)(const char *, const struct stat64 *, int),
136 int depth,
137 int (*statfn)(const char *, struct stat64 *))
138 #else
139 lf_xftw(char *path, int (*fn)(), int depth, int (*statfn)())
140 #endif
141 {
142 int n;
143 int rc, sublen, saverr, attrfd;
144 DIR *dirp;
145 char *subpath, *component;
146 struct stat64 sb;
147 struct dirent *dp;
148 extern dev_t partial_dev;
149
150 /*
151 * Try to get file status.
152 * If unsuccessful, errno will say why.
153 */
154 if ((*statfn)(path, &sb) < 0)
155 return (errno == EACCES? (*fn)(path, &sb, FTW_NS): -1);
156 /*
157 * The stat succeeded, so we know the object exists.
158 * Make sure it is not a mount point for another filesystem.
159 * The following check must be made here because:
160 *
161 * + namefs can be mounted on anything, but a directory
162 * + all other filesystems must be mounted on a directory
163 */
164 if (sb.st_dev != partial_dev) {
165 return (0);
166 }
167 /*
168 * Check for presence of attributes on file
169 */
170 if (pathconf(path, _PC_XATTR_EXISTS) == 1) {
171 attrfd = attropen64(path, ".", O_RDONLY|O_NONBLOCK);
172 } else {
173 attrfd = -1;
174 }
175 /*
176 * If not a directory, call the user function and return.
177 */
178 if ((sb.st_mode & S_IFMT) != S_IFDIR &&
179 (sb.st_mode & IFMT) != IFATTRDIR) {
180 rc = (*fn)(path, &sb, FTW_F);
181 if (rc == 0 && attrfd != -1) {
182 (void) fchdir(attrfd);
183 rc = lf_xftw(".", fn, depth-1, statfn);
184 (void) fchdir(pwdfd);
185 (void) close(attrfd);
186 }
187 return (rc);
188 }
189 /*
190 * The object was a directory and not a mount point.
191 *
192 * Open a file to read the directory
193 */
194 dirp = opendir(path);
195
196 /*
197 * Call the user function, telling it whether
198 * the directory can be read. If it can't be read
199 * call the user function or indicate an error,
200 * depending on the reason it couldn't be read.
201 */
202 if (dirp == NULL)
203 rc = (errno == EACCES? (*fn)(path, &sb, FTW_DNR): -1);
204 else
205 rc = (*fn)(path, &sb, FTW_D);
206 /*
207 * If the directory has attributes, process the
208 * attributes before processing the directory contents.
209 */
210 if (rc == 0 && attrfd != -1) {
211 (void) fchdir(attrfd);
212 rc = lf_xftw(".", fn, depth-1, statfn);
213 (void) fchdir(pwdfd);
214 (void) close(attrfd);
215 }
216 if (rc != 0 || dirp == NULL)
217 return (rc);
218
219 /* Allocate a buffer to hold generated pathnames. */
220 /* LINTED: the length will fit into a signed integer */
221 n = (int)strlen(path);
222 sublen = n + MAXNAMLEN + 1; /* +1 for appended / */
223 subpath = malloc((unsigned)(sublen+1)); /* +1 for NUL */
224 if (subpath == NULL) {
225 saverr = errno;
226 (void) closedir(dirp);
227 errno = saverr;
228 return (-1);
229 }
230
231 /* Create a prefix to which we will append component names */
232 (void) strcpy(subpath, path);
233 if (subpath[0] != '\0' && subpath[n-1] != '/')
234 subpath[n++] = '/';
235 component = &subpath[n];
236 /* LINTED: result will fit into a 32-bit int */
237 sublen -= component - subpath;
238
239 /*
240 * Read the directory one component at a time.
241 * We must ignore "." and "..", but other than that,
242 * just create a path name and call self to check it out.
243 */
244 while ((dp = readdir(dirp)) != NULL) {
245 if (strcmp(dp->d_name, ".") != 0 &&
246 strcmp(dp->d_name, "..") != 0) {
247 long here;
248
249 /* Append component name to the working path */
250 (void) strncpy(component, dp->d_name, sublen);
251 component[sublen - 1] = '\0';
252
253 /*
254 * If we are about to exceed our depth,
255 * remember where we are and close a file.
256 */
257 if (depth <= 1) {
258 here = telldir(dirp);
259 (void) closedir(dirp);
260 }
261
262 /*
263 * Do a recursive call to process the file.
264 * (watch this, sports fans)
265 */
266 rc = lf_xftw(subpath, fn, depth-1, statfn);
267 if (rc != 0) {
268 free(subpath);
269 if (depth > 1)
270 (void) closedir(dirp);
271 return (rc);
272 }
273
274 /*
275 * If we closed the file, try to reopen it.
276 */
277 if (depth <= 1) {
278 dirp = opendir(path);
279 if (dirp == NULL) {
280 free(subpath);
281 return (-1);
282 }
283 seekdir(dirp, here);
284 }
285 }
286 }
287
288 /*
289 * We got out of the subdirectory loop. The return from
290 * the final readdir is in dp. Clean up.
291 */
292 free(subpath);
293 (void) closedir(dirp);
294 return (0);
295 }
296