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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010-2012 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <assert.h> | |
23 | #include <string.h> | |
24 | #include <unistd.h> | |
25 | #include <errno.h> | |
26 | #include <stdlib.h> | |
27 | #include <signal.h> | |
28 | #include <stdio.h> | |
29 | #include <fcntl.h> | |
30 | #include <dirent.h> | |
31 | #include <sys/statvfs.h> | |
32 | ||
33 | #include "macro.h" | |
34 | #include "util.h" | |
35 | #include "log.h" | |
36 | #include "strv.h" | |
37 | #include "path-util.h" | |
a8348796 | 38 | #include "missing.h" |
9eb977db KS |
39 | |
40 | bool path_is_absolute(const char *p) { | |
41 | return p[0] == '/'; | |
42 | } | |
43 | ||
44 | bool is_path(const char *p) { | |
45 | return !!strchr(p, '/'); | |
46 | } | |
47 | ||
48 | char *path_get_file_name(const char *p) { | |
49 | char *r; | |
50 | ||
51 | assert(p); | |
52 | ||
53 | if ((r = strrchr(p, '/'))) | |
54 | return r + 1; | |
55 | ||
56 | return (char*) p; | |
57 | } | |
58 | ||
59 | int path_get_parent(const char *path, char **_r) { | |
60 | const char *e, *a = NULL, *b = NULL, *p; | |
61 | char *r; | |
62 | bool slash = false; | |
63 | ||
64 | assert(path); | |
65 | assert(_r); | |
66 | ||
67 | if (!*path) | |
68 | return -EINVAL; | |
69 | ||
70 | for (e = path; *e; e++) { | |
71 | ||
72 | if (!slash && *e == '/') { | |
73 | a = b; | |
74 | b = e; | |
75 | slash = true; | |
76 | } else if (slash && *e != '/') | |
77 | slash = false; | |
78 | } | |
79 | ||
80 | if (*(e-1) == '/') | |
81 | p = a; | |
82 | else | |
83 | p = b; | |
84 | ||
85 | if (!p) | |
86 | return -EINVAL; | |
87 | ||
88 | if (p == path) | |
89 | r = strdup("/"); | |
90 | else | |
91 | r = strndup(path, p-path); | |
92 | ||
93 | if (!r) | |
94 | return -ENOMEM; | |
95 | ||
96 | *_r = r; | |
97 | return 0; | |
98 | } | |
99 | ||
100 | char **path_split_and_make_absolute(const char *p) { | |
101 | char **l; | |
102 | assert(p); | |
103 | ||
104 | if (!(l = strv_split(p, ":"))) | |
105 | return NULL; | |
106 | ||
107 | if (!path_strv_make_absolute_cwd(l)) { | |
108 | strv_free(l); | |
109 | return NULL; | |
110 | } | |
111 | ||
112 | return l; | |
113 | } | |
114 | ||
115 | char *path_make_absolute(const char *p, const char *prefix) { | |
116 | assert(p); | |
117 | ||
118 | /* Makes every item in the list an absolute path by prepending | |
119 | * the prefix, if specified and necessary */ | |
120 | ||
121 | if (path_is_absolute(p) || !prefix) | |
122 | return strdup(p); | |
123 | ||
b7def684 | 124 | return strjoin(prefix, "/", p, NULL); |
9eb977db KS |
125 | } |
126 | ||
127 | char *path_make_absolute_cwd(const char *p) { | |
128 | char *cwd, *r; | |
129 | ||
130 | assert(p); | |
131 | ||
132 | /* Similar to path_make_absolute(), but prefixes with the | |
133 | * current working directory. */ | |
134 | ||
135 | if (path_is_absolute(p)) | |
136 | return strdup(p); | |
137 | ||
138 | if (!(cwd = get_current_dir_name())) | |
139 | return NULL; | |
140 | ||
141 | r = path_make_absolute(p, cwd); | |
142 | free(cwd); | |
143 | ||
144 | return r; | |
145 | } | |
146 | ||
147 | char **path_strv_make_absolute_cwd(char **l) { | |
148 | char **s; | |
149 | ||
150 | /* Goes through every item in the string list and makes it | |
151 | * absolute. This works in place and won't rollback any | |
152 | * changes on failure. */ | |
153 | ||
154 | STRV_FOREACH(s, l) { | |
155 | char *t; | |
156 | ||
157 | if (!(t = path_make_absolute_cwd(*s))) | |
158 | return NULL; | |
159 | ||
160 | free(*s); | |
161 | *s = t; | |
162 | } | |
163 | ||
164 | return l; | |
165 | } | |
166 | ||
167 | char **path_strv_canonicalize(char **l) { | |
168 | char **s; | |
169 | unsigned k = 0; | |
170 | bool enomem = false; | |
171 | ||
172 | if (strv_isempty(l)) | |
173 | return l; | |
174 | ||
175 | /* Goes through every item in the string list and canonicalize | |
176 | * the path. This works in place and won't rollback any | |
177 | * changes on failure. */ | |
178 | ||
179 | STRV_FOREACH(s, l) { | |
180 | char *t, *u; | |
181 | ||
182 | t = path_make_absolute_cwd(*s); | |
183 | free(*s); | |
184 | ||
185 | if (!t) { | |
186 | enomem = true; | |
187 | continue; | |
188 | } | |
189 | ||
190 | errno = 0; | |
191 | u = canonicalize_file_name(t); | |
192 | free(t); | |
193 | ||
194 | if (!u) { | |
195 | if (errno == ENOMEM || !errno) | |
196 | enomem = true; | |
197 | ||
198 | continue; | |
199 | } | |
200 | ||
201 | l[k++] = u; | |
202 | } | |
203 | ||
204 | l[k] = NULL; | |
205 | ||
206 | if (enomem) | |
207 | return NULL; | |
208 | ||
209 | return l; | |
210 | } | |
211 | ||
212 | char **path_strv_remove_empty(char **l) { | |
213 | char **f, **t; | |
214 | ||
215 | if (!l) | |
216 | return NULL; | |
217 | ||
218 | for (f = t = l; *f; f++) { | |
219 | ||
220 | if (dir_is_empty(*f) > 0) { | |
221 | free(*f); | |
222 | continue; | |
223 | } | |
224 | ||
225 | *(t++) = *f; | |
226 | } | |
227 | ||
228 | *t = NULL; | |
229 | return l; | |
230 | } | |
231 | ||
232 | char *path_kill_slashes(char *path) { | |
233 | char *f, *t; | |
234 | bool slash = false; | |
235 | ||
236 | /* Removes redundant inner and trailing slashes. Modifies the | |
237 | * passed string in-place. | |
238 | * | |
239 | * ///foo///bar/ becomes /foo/bar | |
240 | */ | |
241 | ||
242 | for (f = path, t = path; *f; f++) { | |
243 | ||
244 | if (*f == '/') { | |
245 | slash = true; | |
246 | continue; | |
247 | } | |
248 | ||
249 | if (slash) { | |
250 | slash = false; | |
251 | *(t++) = '/'; | |
252 | } | |
253 | ||
254 | *(t++) = *f; | |
255 | } | |
256 | ||
257 | /* Special rule, if we are talking of the root directory, a | |
258 | trailing slash is good */ | |
259 | ||
260 | if (t == path && slash) | |
261 | *(t++) = '/'; | |
262 | ||
263 | *t = 0; | |
264 | return path; | |
265 | } | |
266 | ||
267 | bool path_startswith(const char *path, const char *prefix) { | |
268 | assert(path); | |
269 | assert(prefix); | |
270 | ||
271 | if ((path[0] == '/') != (prefix[0] == '/')) | |
272 | return false; | |
273 | ||
274 | for (;;) { | |
275 | size_t a, b; | |
276 | ||
277 | path += strspn(path, "/"); | |
278 | prefix += strspn(prefix, "/"); | |
279 | ||
280 | if (*prefix == 0) | |
281 | return true; | |
282 | ||
283 | if (*path == 0) | |
284 | return false; | |
285 | ||
286 | a = strcspn(path, "/"); | |
287 | b = strcspn(prefix, "/"); | |
288 | ||
289 | if (a != b) | |
290 | return false; | |
291 | ||
292 | if (memcmp(path, prefix, a) != 0) | |
293 | return false; | |
294 | ||
295 | path += a; | |
296 | prefix += b; | |
297 | } | |
298 | } | |
299 | ||
300 | bool path_equal(const char *a, const char *b) { | |
301 | assert(a); | |
302 | assert(b); | |
303 | ||
304 | if ((a[0] == '/') != (b[0] == '/')) | |
305 | return false; | |
306 | ||
307 | for (;;) { | |
308 | size_t j, k; | |
309 | ||
310 | a += strspn(a, "/"); | |
311 | b += strspn(b, "/"); | |
312 | ||
313 | if (*a == 0 && *b == 0) | |
314 | return true; | |
315 | ||
316 | if (*a == 0 || *b == 0) | |
317 | return false; | |
318 | ||
319 | j = strcspn(a, "/"); | |
320 | k = strcspn(b, "/"); | |
321 | ||
322 | if (j != k) | |
323 | return false; | |
324 | ||
325 | if (memcmp(a, b, j) != 0) | |
326 | return false; | |
327 | ||
328 | a += j; | |
329 | b += k; | |
330 | } | |
331 | } | |
332 | ||
333 | int path_is_mount_point(const char *t, bool allow_symlink) { | |
9eb977db KS |
334 | char *parent; |
335 | int r; | |
cde9cb34 LP |
336 | struct file_handle *h; |
337 | int mount_id, mount_id_parent; | |
1640a0b6 | 338 | struct stat a, b; |
9eb977db | 339 | |
cde9cb34 LP |
340 | /* We are not actually interested in the file handles, but |
341 | * name_to_handle_at() also passes us the mount ID, hence use | |
342 | * it but throw the handle away */ | |
343 | ||
344 | if (path_equal(t, "/")) | |
345 | return 1; | |
9eb977db | 346 | |
cde9cb34 LP |
347 | h = alloca(MAX_HANDLE_SZ); |
348 | h->handle_bytes = MAX_HANDLE_SZ; | |
349 | ||
350 | r = name_to_handle_at(AT_FDCWD, t, h, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0); | |
9eb977db | 351 | if (r < 0) { |
fa125f4e MM |
352 | if (errno == ENOSYS || errno == ENOTSUP) |
353 | /* This kernel or file system does not support | |
1640a0b6 LP |
354 | * name_to_handle_at(), hence fallback to the |
355 | * traditional stat() logic */ | |
356 | goto fallback; | |
357 | ||
9eb977db KS |
358 | if (errno == ENOENT) |
359 | return 0; | |
360 | ||
361 | return -errno; | |
362 | } | |
363 | ||
364 | r = path_get_parent(t, &parent); | |
365 | if (r < 0) | |
366 | return r; | |
367 | ||
cde9cb34 LP |
368 | h->handle_bytes = MAX_HANDLE_SZ; |
369 | r = name_to_handle_at(AT_FDCWD, parent, h, &mount_id_parent, 0); | |
9eb977db KS |
370 | free(parent); |
371 | ||
1640a0b6 LP |
372 | if (r < 0) { |
373 | /* The parent can't do name_to_handle_at() but the | |
374 | * directory we are interested in can? If so, it must | |
375 | * be a mount point */ | |
376 | if (errno == ENOTSUP) | |
377 | return 1; | |
378 | ||
379 | return -errno; | |
380 | } | |
381 | ||
382 | return mount_id != mount_id_parent; | |
383 | ||
384 | fallback: | |
385 | if (allow_symlink) | |
386 | r = stat(t, &a); | |
387 | else | |
f408b8f1 | 388 | r = lstat(t, &a); |
1640a0b6 | 389 | |
8ac75493 MM |
390 | if (r < 0) { |
391 | if (errno == ENOENT) | |
392 | return 0; | |
393 | ||
9eb977db | 394 | return -errno; |
8ac75493 | 395 | } |
9eb977db | 396 | |
1640a0b6 LP |
397 | r = path_get_parent(t, &parent); |
398 | if (r < 0) | |
399 | return r; | |
cde9cb34 | 400 | |
1640a0b6 LP |
401 | r = lstat(parent, &b); |
402 | free(parent); | |
403 | ||
404 | if (r < 0) | |
405 | return -errno; | |
406 | ||
407 | return a.st_dev != b.st_dev; | |
9eb977db KS |
408 | } |
409 | ||
410 | int path_is_read_only_fs(const char *path) { | |
411 | struct statvfs st; | |
412 | ||
413 | assert(path); | |
414 | ||
415 | if (statvfs(path, &st) < 0) | |
416 | return -errno; | |
417 | ||
418 | return !!(st.f_flag & ST_RDONLY); | |
419 | } |