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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 | ||
91a6489d LP |
138 | cwd = get_current_dir_name(); |
139 | if (!cwd) | |
9eb977db KS |
140 | return NULL; |
141 | ||
142 | r = path_make_absolute(p, cwd); | |
143 | free(cwd); | |
144 | ||
145 | return r; | |
146 | } | |
147 | ||
148 | char **path_strv_make_absolute_cwd(char **l) { | |
149 | char **s; | |
150 | ||
151 | /* Goes through every item in the string list and makes it | |
152 | * absolute. This works in place and won't rollback any | |
153 | * changes on failure. */ | |
154 | ||
155 | STRV_FOREACH(s, l) { | |
156 | char *t; | |
157 | ||
158 | if (!(t = path_make_absolute_cwd(*s))) | |
159 | return NULL; | |
160 | ||
161 | free(*s); | |
162 | *s = t; | |
163 | } | |
164 | ||
165 | return l; | |
166 | } | |
167 | ||
168 | char **path_strv_canonicalize(char **l) { | |
169 | char **s; | |
170 | unsigned k = 0; | |
171 | bool enomem = false; | |
172 | ||
173 | if (strv_isempty(l)) | |
174 | return l; | |
175 | ||
176 | /* Goes through every item in the string list and canonicalize | |
177 | * the path. This works in place and won't rollback any | |
178 | * changes on failure. */ | |
179 | ||
180 | STRV_FOREACH(s, l) { | |
181 | char *t, *u; | |
182 | ||
183 | t = path_make_absolute_cwd(*s); | |
184 | free(*s); | |
c9c7aef2 | 185 | *s = NULL; |
9eb977db KS |
186 | |
187 | if (!t) { | |
188 | enomem = true; | |
189 | continue; | |
190 | } | |
191 | ||
192 | errno = 0; | |
193 | u = canonicalize_file_name(t); | |
9eb977db | 194 | if (!u) { |
874310b7 ZJS |
195 | if (errno == ENOENT) |
196 | u = t; | |
197 | else { | |
198 | free(t); | |
199 | if (errno == ENOMEM || !errno) | |
200 | enomem = true; | |
201 | ||
202 | continue; | |
203 | } | |
91a6489d LP |
204 | } else |
205 | free(t); | |
9eb977db KS |
206 | |
207 | l[k++] = u; | |
208 | } | |
209 | ||
210 | l[k] = NULL; | |
211 | ||
212 | if (enomem) | |
213 | return NULL; | |
214 | ||
215 | return l; | |
216 | } | |
217 | ||
9eb977db KS |
218 | char *path_kill_slashes(char *path) { |
219 | char *f, *t; | |
220 | bool slash = false; | |
221 | ||
222 | /* Removes redundant inner and trailing slashes. Modifies the | |
223 | * passed string in-place. | |
224 | * | |
225 | * ///foo///bar/ becomes /foo/bar | |
226 | */ | |
227 | ||
228 | for (f = path, t = path; *f; f++) { | |
229 | ||
230 | if (*f == '/') { | |
231 | slash = true; | |
232 | continue; | |
233 | } | |
234 | ||
235 | if (slash) { | |
236 | slash = false; | |
237 | *(t++) = '/'; | |
238 | } | |
239 | ||
240 | *(t++) = *f; | |
241 | } | |
242 | ||
243 | /* Special rule, if we are talking of the root directory, a | |
244 | trailing slash is good */ | |
245 | ||
246 | if (t == path && slash) | |
247 | *(t++) = '/'; | |
248 | ||
249 | *t = 0; | |
250 | return path; | |
251 | } | |
252 | ||
424a19f8 | 253 | char* path_startswith(const char *path, const char *prefix) { |
9eb977db KS |
254 | assert(path); |
255 | assert(prefix); | |
256 | ||
257 | if ((path[0] == '/') != (prefix[0] == '/')) | |
424a19f8 | 258 | return NULL; |
9eb977db KS |
259 | |
260 | for (;;) { | |
261 | size_t a, b; | |
262 | ||
263 | path += strspn(path, "/"); | |
264 | prefix += strspn(prefix, "/"); | |
265 | ||
266 | if (*prefix == 0) | |
424a19f8 | 267 | return (char*) path; |
9eb977db KS |
268 | |
269 | if (*path == 0) | |
424a19f8 | 270 | return NULL; |
9eb977db KS |
271 | |
272 | a = strcspn(path, "/"); | |
273 | b = strcspn(prefix, "/"); | |
274 | ||
275 | if (a != b) | |
424a19f8 | 276 | return NULL; |
9eb977db KS |
277 | |
278 | if (memcmp(path, prefix, a) != 0) | |
424a19f8 | 279 | return NULL; |
9eb977db KS |
280 | |
281 | path += a; | |
282 | prefix += b; | |
283 | } | |
284 | } | |
285 | ||
286 | bool path_equal(const char *a, const char *b) { | |
287 | assert(a); | |
288 | assert(b); | |
289 | ||
290 | if ((a[0] == '/') != (b[0] == '/')) | |
291 | return false; | |
292 | ||
293 | for (;;) { | |
294 | size_t j, k; | |
295 | ||
296 | a += strspn(a, "/"); | |
297 | b += strspn(b, "/"); | |
298 | ||
299 | if (*a == 0 && *b == 0) | |
300 | return true; | |
301 | ||
302 | if (*a == 0 || *b == 0) | |
303 | return false; | |
304 | ||
305 | j = strcspn(a, "/"); | |
306 | k = strcspn(b, "/"); | |
307 | ||
308 | if (j != k) | |
309 | return false; | |
310 | ||
311 | if (memcmp(a, b, j) != 0) | |
312 | return false; | |
313 | ||
314 | a += j; | |
315 | b += k; | |
316 | } | |
317 | } | |
318 | ||
319 | int path_is_mount_point(const char *t, bool allow_symlink) { | |
9eb977db KS |
320 | char *parent; |
321 | int r; | |
cde9cb34 LP |
322 | struct file_handle *h; |
323 | int mount_id, mount_id_parent; | |
1640a0b6 | 324 | struct stat a, b; |
9eb977db | 325 | |
cde9cb34 LP |
326 | /* We are not actually interested in the file handles, but |
327 | * name_to_handle_at() also passes us the mount ID, hence use | |
328 | * it but throw the handle away */ | |
329 | ||
330 | if (path_equal(t, "/")) | |
331 | return 1; | |
9eb977db | 332 | |
cde9cb34 LP |
333 | h = alloca(MAX_HANDLE_SZ); |
334 | h->handle_bytes = MAX_HANDLE_SZ; | |
335 | ||
336 | r = name_to_handle_at(AT_FDCWD, t, h, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0); | |
9eb977db | 337 | if (r < 0) { |
fa125f4e MM |
338 | if (errno == ENOSYS || errno == ENOTSUP) |
339 | /* This kernel or file system does not support | |
1640a0b6 LP |
340 | * name_to_handle_at(), hence fallback to the |
341 | * traditional stat() logic */ | |
342 | goto fallback; | |
343 | ||
9eb977db KS |
344 | if (errno == ENOENT) |
345 | return 0; | |
346 | ||
347 | return -errno; | |
348 | } | |
349 | ||
350 | r = path_get_parent(t, &parent); | |
351 | if (r < 0) | |
352 | return r; | |
353 | ||
cde9cb34 LP |
354 | h->handle_bytes = MAX_HANDLE_SZ; |
355 | r = name_to_handle_at(AT_FDCWD, parent, h, &mount_id_parent, 0); | |
9eb977db KS |
356 | free(parent); |
357 | ||
1640a0b6 LP |
358 | if (r < 0) { |
359 | /* The parent can't do name_to_handle_at() but the | |
360 | * directory we are interested in can? If so, it must | |
361 | * be a mount point */ | |
362 | if (errno == ENOTSUP) | |
363 | return 1; | |
364 | ||
365 | return -errno; | |
366 | } | |
367 | ||
368 | return mount_id != mount_id_parent; | |
369 | ||
370 | fallback: | |
371 | if (allow_symlink) | |
372 | r = stat(t, &a); | |
373 | else | |
f408b8f1 | 374 | r = lstat(t, &a); |
1640a0b6 | 375 | |
8ac75493 MM |
376 | if (r < 0) { |
377 | if (errno == ENOENT) | |
378 | return 0; | |
379 | ||
9eb977db | 380 | return -errno; |
8ac75493 | 381 | } |
9eb977db | 382 | |
1640a0b6 LP |
383 | r = path_get_parent(t, &parent); |
384 | if (r < 0) | |
385 | return r; | |
cde9cb34 | 386 | |
1640a0b6 LP |
387 | r = lstat(parent, &b); |
388 | free(parent); | |
389 | ||
390 | if (r < 0) | |
391 | return -errno; | |
392 | ||
393 | return a.st_dev != b.st_dev; | |
9eb977db KS |
394 | } |
395 | ||
396 | int path_is_read_only_fs(const char *path) { | |
397 | struct statvfs st; | |
398 | ||
399 | assert(path); | |
400 | ||
401 | if (statvfs(path, &st) < 0) | |
402 | return -errno; | |
403 | ||
404 | return !!(st.f_flag & ST_RDONLY); | |
405 | } |