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1 office 1 /*
2 * Copyright © 2010 Codethink Limited
3 * Copyright © 2010 Novell, Inc.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the licence, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
17 *
18 * Authors: Vincent Untz <vuntz@gnome.org>
19 * Ryan Lortie <desrt@desrt.ca>
20 */
21  
22 #include "config.h"
23  
24 #include <stdio.h>
25 #include <string.h>
26  
27 #include "gfile.h"
28 #include "gfileinfo.h"
29 #include "gfilemonitor.h"
30 #include "gsimplepermission.h"
31 #include "gsettingsbackend.h"
32  
33  
34 #define G_TYPE_KEYFILE_SETTINGS_BACKEND (g_keyfile_settings_backend_get_type ())
35 #define G_KEYFILE_SETTINGS_BACKEND(inst) (G_TYPE_CHECK_INSTANCE_CAST ((inst), \
36 G_TYPE_KEYFILE_SETTINGS_BACKEND, \
37 GKeyfileSettingsBackend))
38 #define G_IS_KEYFILE_SETTINGS_BACKEND(inst) (G_TYPE_CHECK_INSTANCE_TYPE ((inst), \
39 G_TYPE_KEYFILE_SETTINGS_BACKEND))
40  
41  
42 typedef GSettingsBackendClass GKeyfileSettingsBackendClass;
43  
44 typedef struct
45 {
46 GSettingsBackend parent_instance;
47  
48 GKeyFile *keyfile;
49 GPermission *permission;
50 gboolean writable;
51  
52 gchar *prefix;
53 gint prefix_len;
54 gchar *root_group;
55 gint root_group_len;
56  
57 GFile *file;
58 GFileMonitor *file_monitor;
59 guint8 digest[32];
60 GFile *dir;
61 GFileMonitor *dir_monitor;
62 } GKeyfileSettingsBackend;
63  
64 static GType g_keyfile_settings_backend_get_type (void);
65 G_DEFINE_TYPE (GKeyfileSettingsBackend,
66 g_keyfile_settings_backend,
67 G_TYPE_SETTINGS_BACKEND)
68  
69 static void
70 compute_checksum (guint8 *digest,
71 gconstpointer contents,
72 gsize length)
73 {
74 GChecksum *checksum;
75 gsize len = 32;
76  
77 checksum = g_checksum_new (G_CHECKSUM_SHA256);
78 g_checksum_update (checksum, contents, length);
79 g_checksum_get_digest (checksum, digest, &len);
80 g_checksum_free (checksum);
81 g_assert (len == 32);
82 }
83  
84 static void
85 g_keyfile_settings_backend_keyfile_write (GKeyfileSettingsBackend *kfsb)
86 {
87 gchar *contents;
88 gsize length;
89  
90 contents = g_key_file_to_data (kfsb->keyfile, &length, NULL);
91 g_file_replace_contents (kfsb->file, contents, length, NULL, FALSE,
92 G_FILE_CREATE_REPLACE_DESTINATION,
93 NULL, NULL, NULL);
94  
95 compute_checksum (kfsb->digest, contents, length);
96 g_free (contents);
97 }
98  
99 static gboolean
100 group_name_matches (const gchar *group_name,
101 const gchar *prefix)
102 {
103 /* sort of like g_str_has_prefix() except that it must be an exact
104 * match or the prefix followed by '/'.
105 *
106 * for example 'a' is a prefix of 'a' and 'a/b' but not 'ab'.
107 */
108 gint i;
109  
110 for (i = 0; prefix[i]; i++)
111 if (prefix[i] != group_name[i])
112 return FALSE;
113  
114 return group_name[i] == '\0' || group_name[i] == '/';
115 }
116  
117 static gboolean
118 convert_path (GKeyfileSettingsBackend *kfsb,
119 const gchar *key,
120 gchar **group,
121 gchar **basename)
122 {
123 gint key_len = strlen (key);
124 gint i;
125  
126 if (key_len < kfsb->prefix_len ||
127 memcmp (key, kfsb->prefix, kfsb->prefix_len) != 0)
128 return FALSE;
129  
130 key_len -= kfsb->prefix_len;
131 key += kfsb->prefix_len;
132  
133 for (i = key_len; i >= 0; i--)
134 if (key[i] == '/')
135 break;
136  
137 if (kfsb->root_group)
138 {
139 /* if a root_group was specified, make sure the user hasn't given
140 * a path that ghosts that group name
141 */
142 if (i == kfsb->root_group_len && memcmp (key, kfsb->root_group, i) == 0)
143 return FALSE;
144 }
145 else
146 {
147 /* if no root_group was given, ensure that the user gave a path */
148 if (i == -1)
149 return FALSE;
150 }
151  
152 if (group)
153 {
154 if (i >= 0)
155 {
156 *group = g_memdup (key, i + 1);
157 (*group)[i] = '\0';
158 }
159 else
160 *group = g_strdup (kfsb->root_group);
161 }
162  
163 if (basename)
164 *basename = g_memdup (key + i + 1, key_len - i);
165  
166 return TRUE;
167 }
168  
169 static gboolean
170 path_is_valid (GKeyfileSettingsBackend *kfsb,
171 const gchar *path)
172 {
173 return convert_path (kfsb, path, NULL, NULL);
174 }
175  
176 static GVariant *
177 get_from_keyfile (GKeyfileSettingsBackend *kfsb,
178 const GVariantType *type,
179 const gchar *key)
180 {
181 GVariant *return_value = NULL;
182 gchar *group, *name;
183  
184 if (convert_path (kfsb, key, &group, &name))
185 {
186 gchar *str;
187  
188 g_assert (*name);
189  
190 str = g_key_file_get_value (kfsb->keyfile, group, name, NULL);
191  
192 if (str)
193 {
194 return_value = g_variant_parse (type, str, NULL, NULL, NULL);
195 g_free (str);
196 }
197  
198 g_free (group);
199 g_free (name);
200 }
201  
202 return return_value;
203 }
204  
205 static gboolean
206 set_to_keyfile (GKeyfileSettingsBackend *kfsb,
207 const gchar *key,
208 GVariant *value)
209 {
210 gchar *group, *name;
211  
212 if (convert_path (kfsb, key, &group, &name))
213 {
214 if (value)
215 {
216 gchar *str = g_variant_print (value, FALSE);
217 g_key_file_set_value (kfsb->keyfile, group, name, str);
218 g_variant_unref (g_variant_ref_sink (value));
219 g_free (str);
220 }
221 else
222 {
223 if (*name == '\0')
224 {
225 gchar **groups;
226 gint i;
227  
228 groups = g_key_file_get_groups (kfsb->keyfile, NULL);
229  
230 for (i = 0; groups[i]; i++)
231 if (group_name_matches (groups[i], group))
232 g_key_file_remove_group (kfsb->keyfile, groups[i], NULL);
233  
234 g_strfreev (groups);
235 }
236 else
237 g_key_file_remove_key (kfsb->keyfile, group, name, NULL);
238 }
239  
240 g_free (group);
241 g_free (name);
242  
243 return TRUE;
244 }
245  
246 return FALSE;
247 }
248  
249 static GVariant *
250 g_keyfile_settings_backend_read (GSettingsBackend *backend,
251 const gchar *key,
252 const GVariantType *expected_type,
253 gboolean default_value)
254 {
255 GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
256  
257 if (default_value)
258 return NULL;
259  
260 return get_from_keyfile (kfsb, expected_type, key);
261 }
262  
263 typedef struct
264 {
265 GKeyfileSettingsBackend *kfsb;
266 gboolean failed;
267 } WriteManyData;
268  
269 static gboolean
270 g_keyfile_settings_backend_write_one (gpointer key,
271 gpointer value,
272 gpointer user_data)
273 {
274 WriteManyData *data = user_data;
275 gboolean success;
276  
277 success = set_to_keyfile (data->kfsb, key, value);
278 g_assert (success);
279  
280 return FALSE;
281 }
282  
283 static gboolean
284 g_keyfile_settings_backend_check_one (gpointer key,
285 gpointer value,
286 gpointer user_data)
287 {
288 WriteManyData *data = user_data;
289  
290 return data->failed = !path_is_valid (data->kfsb, key);
291 }
292  
293 static gboolean
294 g_keyfile_settings_backend_write_tree (GSettingsBackend *backend,
295 GTree *tree,
296 gpointer origin_tag)
297 {
298 WriteManyData data = { G_KEYFILE_SETTINGS_BACKEND (backend) };
299  
300 if (!data.kfsb->writable)
301 return FALSE;
302  
303 g_tree_foreach (tree, g_keyfile_settings_backend_check_one, &data);
304  
305 if (data.failed)
306 return FALSE;
307  
308 g_tree_foreach (tree, g_keyfile_settings_backend_write_one, &data);
309 g_keyfile_settings_backend_keyfile_write (data.kfsb);
310  
311 g_settings_backend_changed_tree (backend, tree, origin_tag);
312  
313 return TRUE;
314 }
315  
316 static gboolean
317 g_keyfile_settings_backend_write (GSettingsBackend *backend,
318 const gchar *key,
319 GVariant *value,
320 gpointer origin_tag)
321 {
322 GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
323 gboolean success;
324  
325 if (!kfsb->writable)
326 return FALSE;
327  
328 success = set_to_keyfile (kfsb, key, value);
329  
330 if (success)
331 {
332 g_settings_backend_changed (backend, key, origin_tag);
333 g_keyfile_settings_backend_keyfile_write (kfsb);
334 }
335  
336 return success;
337 }
338  
339 static void
340 g_keyfile_settings_backend_reset (GSettingsBackend *backend,
341 const gchar *key,
342 gpointer origin_tag)
343 {
344 GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
345  
346 if (set_to_keyfile (kfsb, key, NULL))
347 g_keyfile_settings_backend_keyfile_write (kfsb);
348  
349 g_settings_backend_changed (backend, key, origin_tag);
350 }
351  
352 static gboolean
353 g_keyfile_settings_backend_get_writable (GSettingsBackend *backend,
354 const gchar *name)
355 {
356 GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
357  
358 return kfsb->writable && path_is_valid (kfsb, name);
359 }
360  
361 static GPermission *
362 g_keyfile_settings_backend_get_permission (GSettingsBackend *backend,
363 const gchar *path)
364 {
365 GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
366  
367 return g_object_ref (kfsb->permission);
368 }
369  
370 static void
371 keyfile_to_tree (GKeyfileSettingsBackend *kfsb,
372 GTree *tree,
373 GKeyFile *keyfile,
374 gboolean dup_check)
375 {
376 gchar **groups;
377 gint i;
378  
379 groups = g_key_file_get_groups (keyfile, NULL);
380 for (i = 0; groups[i]; i++)
381 {
382 gboolean is_root_group;
383 gchar **keys;
384 gint j;
385  
386 is_root_group = g_strcmp0 (kfsb->root_group, groups[i]) == 0;
387  
388 /* reject group names that will form invalid key names */
389 if (!is_root_group &&
390 (g_str_has_prefix (groups[i], "/") ||
391 g_str_has_suffix (groups[i], "/") || strstr (groups[i], "//")))
392 continue;
393  
394 keys = g_key_file_get_keys (keyfile, groups[i], NULL, NULL);
395 g_assert (keys != NULL);
396  
397 for (j = 0; keys[j]; j++)
398 {
399 gchar *path, *value;
400  
401 /* reject key names with slashes in them */
402 if (strchr (keys[j], '/'))
403 continue;
404  
405 if (is_root_group)
406 path = g_strdup_printf ("%s%s", kfsb->prefix, keys[j]);
407 else
408 path = g_strdup_printf ("%s%s/%s", kfsb->prefix, groups[i], keys[j]);
409  
410 value = g_key_file_get_value (keyfile, groups[i], keys[j], NULL);
411  
412 if (dup_check && g_strcmp0 (g_tree_lookup (tree, path), value) == 0)
413 {
414 g_tree_remove (tree, path);
415 g_free (value);
416 g_free (path);
417 }
418 else
419 g_tree_insert (tree, path, value);
420 }
421  
422 g_strfreev (keys);
423 }
424 g_strfreev (groups);
425 }
426  
427 static void
428 g_keyfile_settings_backend_keyfile_reload (GKeyfileSettingsBackend *kfsb)
429 {
430 guint8 digest[32];
431 gchar *contents;
432 gsize length;
433  
434 contents = NULL;
435 length = 0;
436  
437 g_file_load_contents (kfsb->file, NULL, &contents, &length, NULL, NULL);
438 compute_checksum (digest, contents, length);
439  
440 if (memcmp (kfsb->digest, digest, sizeof digest) != 0)
441 {
442 GKeyFile *keyfiles[2];
443 GTree *tree;
444  
445 tree = g_tree_new_full ((GCompareDataFunc) strcmp, NULL,
446 g_free, g_free);
447  
448 keyfiles[0] = kfsb->keyfile;
449 keyfiles[1] = g_key_file_new ();
450  
451 if (length > 0)
452 g_key_file_load_from_data (keyfiles[1], contents, length,
453 G_KEY_FILE_KEEP_COMMENTS |
454 G_KEY_FILE_KEEP_TRANSLATIONS, NULL);
455  
456 keyfile_to_tree (kfsb, tree, keyfiles[0], FALSE);
457 keyfile_to_tree (kfsb, tree, keyfiles[1], TRUE);
458 g_key_file_free (keyfiles[0]);
459 kfsb->keyfile = keyfiles[1];
460  
461 if (g_tree_nnodes (tree) > 0)
462 g_settings_backend_changed_tree (&kfsb->parent_instance, tree, NULL);
463  
464 g_tree_unref (tree);
465  
466 memcpy (kfsb->digest, digest, sizeof digest);
467 }
468  
469 g_free (contents);
470 }
471  
472 static void
473 g_keyfile_settings_backend_keyfile_writable (GKeyfileSettingsBackend *kfsb)
474 {
475 GFileInfo *fileinfo;
476 gboolean writable;
477  
478 fileinfo = g_file_query_info (kfsb->dir, "access::*", 0, NULL, NULL);
479  
480 if (fileinfo)
481 {
482 writable =
483 g_file_info_get_attribute_boolean (fileinfo, G_FILE_ATTRIBUTE_ACCESS_CAN_WRITE) &&
484 g_file_info_get_attribute_boolean (fileinfo, G_FILE_ATTRIBUTE_ACCESS_CAN_EXECUTE);
485 g_object_unref (fileinfo);
486 }
487 else
488 writable = FALSE;
489  
490 if (writable != kfsb->writable)
491 {
492 kfsb->writable = writable;
493 g_settings_backend_path_writable_changed (&kfsb->parent_instance, "/");
494 }
495 }
496  
497 static void
498 g_keyfile_settings_backend_finalize (GObject *object)
499 {
500 GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (object);
501  
502 g_key_file_free (kfsb->keyfile);
503 g_object_unref (kfsb->permission);
504  
505 g_file_monitor_cancel (kfsb->file_monitor);
506 g_object_unref (kfsb->file_monitor);
507 g_object_unref (kfsb->file);
508  
509 g_file_monitor_cancel (kfsb->dir_monitor);
510 g_object_unref (kfsb->dir_monitor);
511 g_object_unref (kfsb->dir);
512  
513 g_free (kfsb->root_group);
514 g_free (kfsb->prefix);
515  
516 G_OBJECT_CLASS (g_keyfile_settings_backend_parent_class)
517 ->finalize (object);
518 }
519  
520 static void
521 g_keyfile_settings_backend_init (GKeyfileSettingsBackend *kfsb)
522 {
523 }
524  
525 static void
526 g_keyfile_settings_backend_class_init (GKeyfileSettingsBackendClass *class)
527 {
528 GObjectClass *object_class = G_OBJECT_CLASS (class);
529  
530 object_class->finalize = g_keyfile_settings_backend_finalize;
531  
532 class->read = g_keyfile_settings_backend_read;
533 class->write = g_keyfile_settings_backend_write;
534 class->write_tree = g_keyfile_settings_backend_write_tree;
535 class->reset = g_keyfile_settings_backend_reset;
536 class->get_writable = g_keyfile_settings_backend_get_writable;
537 class->get_permission = g_keyfile_settings_backend_get_permission;
538 /* No need to implement subscribed/unsubscribe: the only point would be to
539 * stop monitoring the file when there's no GSettings anymore, which is no
540 * big win.
541 */
542 }
543  
544 static void
545 file_changed (GFileMonitor *monitor,
546 GFile *file,
547 GFile *other_file,
548 GFileMonitorEvent event_type,
549 gpointer user_data)
550 {
551 GKeyfileSettingsBackend *kfsb = user_data;
552  
553 /* Ignore file deletions, let the GKeyFile content remain in tact. */
554 if (event_type != G_FILE_MONITOR_EVENT_DELETED)
555 g_keyfile_settings_backend_keyfile_reload (kfsb);
556 }
557  
558 static void
559 dir_changed (GFileMonitor *monitor,
560 GFile *file,
561 GFile *other_file,
562 GFileMonitorEvent event_type,
563 gpointer user_data)
564 {
565 GKeyfileSettingsBackend *kfsb = user_data;
566  
567 g_keyfile_settings_backend_keyfile_writable (kfsb);
568 }
569  
570 /**
571 * g_keyfile_settings_backend_new:
572 * @filename: the filename of the keyfile
573 * @root_path: the path under which all settings keys appear
574 * @root_group: (allow-none): the group name corresponding to
575 * @root_path, or %NULL
576 *
577 * Creates a keyfile-backed #GSettingsBackend.
578 *
579 * The filename of the keyfile to use is given by @filename.
580 *
581 * All settings read to or written from the backend must fall under the
582 * path given in @root_path (which must start and end with a slash and
583 * not contain two consecutive slashes). @root_path may be "/".
584 *
585 * If @root_group is non-%NULL then it specifies the name of the keyfile
586 * group used for keys that are written directly below @root_path. For
587 * example, if @root_path is "/apps/example/" and @root_group is
588 * "toplevel", then settings the key "/apps/example/enabled" to a value
589 * of %TRUE will cause the following to appear in the keyfile:
590 *
591 * |[
592 * [toplevel]
593 * enabled=true
594 * ]|
595 *
596 * If @root_group is %NULL then it is not permitted to store keys
597 * directly below the @root_path.
598 *
599 * For keys not stored directly below @root_path (ie: in a sub-path),
600 * the name of the subpath (with the final slash stripped) is used as
601 * the name of the keyfile group. To continue the example, if
602 * "/apps/example/profiles/default/font-size" were set to
603 * 12 then the following would appear in the keyfile:
604 *
605 * |[
606 * [profiles/default]
607 * font-size=12
608 * ]|
609 *
610 * The backend will refuse writes (and return writability as being
611 * %FALSE) for keys outside of @root_path and, in the event that
612 * @root_group is %NULL, also for keys directly under @root_path.
613 * Writes will also be refused if the backend detects that it has the
614 * inability to rewrite the keyfile (ie: the containing directory is not
615 * writable).
616 *
617 * There is no checking done for your key namespace clashing with the
618 * syntax of the key file format. For example, if you have '[' or ']'
619 * characters in your path names or '=' in your key names you may be in
620 * trouble.
621 *
622 * Returns: (transfer full): a keyfile-backed #GSettingsBackend
623 **/
624 GSettingsBackend *
625 g_keyfile_settings_backend_new (const gchar *filename,
626 const gchar *root_path,
627 const gchar *root_group)
628 {
629 GKeyfileSettingsBackend *kfsb;
630  
631 g_return_val_if_fail (filename != NULL, NULL);
632 g_return_val_if_fail (root_path != NULL, NULL);
633 g_return_val_if_fail (g_str_has_prefix (root_path, "/"), NULL);
634 g_return_val_if_fail (g_str_has_suffix (root_path, "/"), NULL);
635 g_return_val_if_fail (strstr (root_path, "//") == NULL, NULL);
636  
637 kfsb = g_object_new (G_TYPE_KEYFILE_SETTINGS_BACKEND, NULL);
638 kfsb->keyfile = g_key_file_new ();
639 kfsb->permission = g_simple_permission_new (TRUE);
640  
641 kfsb->file = g_file_new_for_path (filename);
642 kfsb->dir = g_file_get_parent (kfsb->file);
643 g_file_make_directory_with_parents (kfsb->dir, NULL, NULL);
644  
645 kfsb->file_monitor = g_file_monitor (kfsb->file, 0, NULL, NULL);
646 kfsb->dir_monitor = g_file_monitor (kfsb->dir, 0, NULL, NULL);
647  
648 kfsb->prefix_len = strlen (root_path);
649 kfsb->prefix = g_strdup (root_path);
650  
651 if (root_group)
652 {
653 kfsb->root_group_len = strlen (root_group);
654 kfsb->root_group = g_strdup (root_group);
655 }
656  
657 compute_checksum (kfsb->digest, NULL, 0);
658  
659 g_signal_connect (kfsb->file_monitor, "changed",
660 G_CALLBACK (file_changed), kfsb);
661 g_signal_connect (kfsb->dir_monitor, "changed",
662 G_CALLBACK (dir_changed), kfsb);
663  
664 g_keyfile_settings_backend_keyfile_writable (kfsb);
665 g_keyfile_settings_backend_keyfile_reload (kfsb);
666  
667 return G_SETTINGS_BACKEND (kfsb);
668 }