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1 | /*** | |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2008-2012 Kay Sievers <kay@vrfy.org> | |
5 | ||
6 | systemd is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU Lesser General Public License as published by | |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | systemd is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public License | |
17 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
18 | ***/ | |
19 | ||
20 | #include <errno.h> | |
21 | #include <stddef.h> | |
22 | #include <stdlib.h> | |
23 | #include <string.h> | |
24 | ||
25 | #include "alloc-util.h" | |
26 | #include "libudev-private.h" | |
27 | ||
28 | /** | |
29 | * SECTION:libudev-list | |
30 | * @short_description: list operation | |
31 | * | |
32 | * Libudev list operations. | |
33 | */ | |
34 | ||
35 | /** | |
36 | * udev_list_entry: | |
37 | * | |
38 | * Opaque object representing one entry in a list. An entry contains | |
39 | * contains a name, and optionally a value. | |
40 | */ | |
41 | struct udev_list_entry { | |
42 | struct udev_list_node node; | |
43 | struct udev_list *list; | |
44 | char *name; | |
45 | char *value; | |
46 | int num; | |
47 | }; | |
48 | ||
49 | /* the list's head points to itself if empty */ | |
50 | void udev_list_node_init(struct udev_list_node *list) | |
51 | { | |
52 | list->next = list; | |
53 | list->prev = list; | |
54 | } | |
55 | ||
56 | int udev_list_node_is_empty(struct udev_list_node *list) | |
57 | { | |
58 | return list->next == list; | |
59 | } | |
60 | ||
61 | static void udev_list_node_insert_between(struct udev_list_node *new, | |
62 | struct udev_list_node *prev, | |
63 | struct udev_list_node *next) | |
64 | { | |
65 | next->prev = new; | |
66 | new->next = next; | |
67 | new->prev = prev; | |
68 | prev->next = new; | |
69 | } | |
70 | ||
71 | void udev_list_node_append(struct udev_list_node *new, struct udev_list_node *list) | |
72 | { | |
73 | udev_list_node_insert_between(new, list->prev, list); | |
74 | } | |
75 | ||
76 | void udev_list_node_remove(struct udev_list_node *entry) | |
77 | { | |
78 | struct udev_list_node *prev = entry->prev; | |
79 | struct udev_list_node *next = entry->next; | |
80 | ||
81 | next->prev = prev; | |
82 | prev->next = next; | |
83 | ||
84 | entry->prev = NULL; | |
85 | entry->next = NULL; | |
86 | } | |
87 | ||
88 | /* return list entry which embeds this node */ | |
89 | static inline struct udev_list_entry *list_node_to_entry(struct udev_list_node *node) | |
90 | { | |
91 | return container_of(node, struct udev_list_entry, node); | |
92 | } | |
93 | ||
94 | void udev_list_init(struct udev *udev, struct udev_list *list, bool unique) | |
95 | { | |
96 | memzero(list, sizeof(struct udev_list)); | |
97 | list->udev = udev; | |
98 | list->unique = unique; | |
99 | udev_list_node_init(&list->node); | |
100 | } | |
101 | ||
102 | /* insert entry into a list as the last element */ | |
103 | static void udev_list_entry_append(struct udev_list_entry *new, struct udev_list *list) | |
104 | { | |
105 | /* inserting before the list head make the node the last node in the list */ | |
106 | udev_list_node_insert_between(&new->node, list->node.prev, &list->node); | |
107 | new->list = list; | |
108 | } | |
109 | ||
110 | /* insert entry into a list, before a given existing entry */ | |
111 | static void udev_list_entry_insert_before(struct udev_list_entry *new, struct udev_list_entry *entry) | |
112 | { | |
113 | udev_list_node_insert_between(&new->node, entry->node.prev, &entry->node); | |
114 | new->list = entry->list; | |
115 | } | |
116 | ||
117 | /* binary search in sorted array */ | |
118 | static int list_search(struct udev_list *list, const char *name) | |
119 | { | |
120 | unsigned int first, last; | |
121 | ||
122 | first = 0; | |
123 | last = list->entries_cur; | |
124 | while (first < last) { | |
125 | unsigned int i; | |
126 | int cmp; | |
127 | ||
128 | i = (first + last)/2; | |
129 | cmp = strcmp(name, list->entries[i]->name); | |
130 | if (cmp < 0) | |
131 | last = i; | |
132 | else if (cmp > 0) | |
133 | first = i+1; | |
134 | else | |
135 | return i; | |
136 | } | |
137 | ||
138 | /* not found, return negative insertion-index+1 */ | |
139 | return -(first+1); | |
140 | } | |
141 | ||
142 | struct udev_list_entry *udev_list_entry_add(struct udev_list *list, const char *name, const char *value) | |
143 | { | |
144 | struct udev_list_entry *entry; | |
145 | int i = 0; | |
146 | ||
147 | if (list->unique) { | |
148 | /* lookup existing name or insertion-index */ | |
149 | i = list_search(list, name); | |
150 | if (i >= 0) { | |
151 | entry = list->entries[i]; | |
152 | ||
153 | free(entry->value); | |
154 | if (value == NULL) { | |
155 | entry->value = NULL; | |
156 | return entry; | |
157 | } | |
158 | entry->value = strdup(value); | |
159 | if (entry->value == NULL) | |
160 | return NULL; | |
161 | return entry; | |
162 | } | |
163 | } | |
164 | ||
165 | /* add new name */ | |
166 | entry = new0(struct udev_list_entry, 1); | |
167 | if (entry == NULL) | |
168 | return NULL; | |
169 | entry->name = strdup(name); | |
170 | if (entry->name == NULL) { | |
171 | free(entry); | |
172 | return NULL; | |
173 | } | |
174 | if (value != NULL) { | |
175 | entry->value = strdup(value); | |
176 | if (entry->value == NULL) { | |
177 | free(entry->name); | |
178 | free(entry); | |
179 | return NULL; | |
180 | } | |
181 | } | |
182 | ||
183 | if (list->unique) { | |
184 | /* allocate or enlarge sorted array if needed */ | |
185 | if (list->entries_cur >= list->entries_max) { | |
186 | struct udev_list_entry **entries; | |
187 | unsigned int add; | |
188 | ||
189 | add = list->entries_max; | |
190 | if (add < 1) | |
191 | add = 64; | |
192 | entries = realloc(list->entries, (list->entries_max + add) * sizeof(struct udev_list_entry *)); | |
193 | if (entries == NULL) { | |
194 | free(entry->name); | |
195 | free(entry->value); | |
196 | free(entry); | |
197 | return NULL; | |
198 | } | |
199 | list->entries = entries; | |
200 | list->entries_max += add; | |
201 | } | |
202 | ||
203 | /* the negative i returned the insertion index */ | |
204 | i = (-i)-1; | |
205 | ||
206 | /* insert into sorted list */ | |
207 | if ((unsigned int)i < list->entries_cur) | |
208 | udev_list_entry_insert_before(entry, list->entries[i]); | |
209 | else | |
210 | udev_list_entry_append(entry, list); | |
211 | ||
212 | /* insert into sorted array */ | |
213 | memmove(&list->entries[i+1], &list->entries[i], | |
214 | (list->entries_cur - i) * sizeof(struct udev_list_entry *)); | |
215 | list->entries[i] = entry; | |
216 | list->entries_cur++; | |
217 | } else { | |
218 | udev_list_entry_append(entry, list); | |
219 | } | |
220 | ||
221 | return entry; | |
222 | } | |
223 | ||
224 | void udev_list_entry_delete(struct udev_list_entry *entry) | |
225 | { | |
226 | if (entry->list->entries != NULL) { | |
227 | int i; | |
228 | struct udev_list *list = entry->list; | |
229 | ||
230 | /* remove entry from sorted array */ | |
231 | i = list_search(list, entry->name); | |
232 | if (i >= 0) { | |
233 | memmove(&list->entries[i], &list->entries[i+1], | |
234 | ((list->entries_cur-1) - i) * sizeof(struct udev_list_entry *)); | |
235 | list->entries_cur--; | |
236 | } | |
237 | } | |
238 | ||
239 | udev_list_node_remove(&entry->node); | |
240 | free(entry->name); | |
241 | free(entry->value); | |
242 | free(entry); | |
243 | } | |
244 | ||
245 | void udev_list_cleanup(struct udev_list *list) | |
246 | { | |
247 | struct udev_list_entry *entry_loop; | |
248 | struct udev_list_entry *entry_tmp; | |
249 | ||
250 | list->entries = mfree(list->entries); | |
251 | list->entries_cur = 0; | |
252 | list->entries_max = 0; | |
253 | udev_list_entry_foreach_safe(entry_loop, entry_tmp, udev_list_get_entry(list)) | |
254 | udev_list_entry_delete(entry_loop); | |
255 | } | |
256 | ||
257 | struct udev_list_entry *udev_list_get_entry(struct udev_list *list) | |
258 | { | |
259 | if (udev_list_node_is_empty(&list->node)) | |
260 | return NULL; | |
261 | return list_node_to_entry(list->node.next); | |
262 | } | |
263 | ||
264 | /** | |
265 | * udev_list_entry_get_next: | |
266 | * @list_entry: current entry | |
267 | * | |
268 | * Get the next entry from the list. | |
269 | * | |
270 | * Returns: udev_list_entry, #NULL if no more entries are available. | |
271 | */ | |
272 | _public_ struct udev_list_entry *udev_list_entry_get_next(struct udev_list_entry *list_entry) | |
273 | { | |
274 | struct udev_list_node *next; | |
275 | ||
276 | if (list_entry == NULL) | |
277 | return NULL; | |
278 | next = list_entry->node.next; | |
279 | /* empty list or no more entries */ | |
280 | if (next == &list_entry->list->node) | |
281 | return NULL; | |
282 | return list_node_to_entry(next); | |
283 | } | |
284 | ||
285 | /** | |
286 | * udev_list_entry_get_by_name: | |
287 | * @list_entry: current entry | |
288 | * @name: name string to match | |
289 | * | |
290 | * Lookup an entry in the list with a certain name. | |
291 | * | |
292 | * Returns: udev_list_entry, #NULL if no matching entry is found. | |
293 | */ | |
294 | _public_ struct udev_list_entry *udev_list_entry_get_by_name(struct udev_list_entry *list_entry, const char *name) | |
295 | { | |
296 | int i; | |
297 | ||
298 | if (list_entry == NULL) | |
299 | return NULL; | |
300 | ||
301 | if (!list_entry->list->unique) | |
302 | return NULL; | |
303 | ||
304 | i = list_search(list_entry->list, name); | |
305 | if (i < 0) | |
306 | return NULL; | |
307 | return list_entry->list->entries[i]; | |
308 | } | |
309 | ||
310 | /** | |
311 | * udev_list_entry_get_name: | |
312 | * @list_entry: current entry | |
313 | * | |
314 | * Get the name of a list entry. | |
315 | * | |
316 | * Returns: the name string of this entry. | |
317 | */ | |
318 | _public_ const char *udev_list_entry_get_name(struct udev_list_entry *list_entry) | |
319 | { | |
320 | if (list_entry == NULL) | |
321 | return NULL; | |
322 | return list_entry->name; | |
323 | } | |
324 | ||
325 | /** | |
326 | * udev_list_entry_get_value: | |
327 | * @list_entry: current entry | |
328 | * | |
329 | * Get the value of list entry. | |
330 | * | |
331 | * Returns: the value string of this entry. | |
332 | */ | |
333 | _public_ const char *udev_list_entry_get_value(struct udev_list_entry *list_entry) | |
334 | { | |
335 | if (list_entry == NULL) | |
336 | return NULL; | |
337 | return list_entry->value; | |
338 | } | |
339 | ||
340 | int udev_list_entry_get_num(struct udev_list_entry *list_entry) | |
341 | { | |
342 | if (list_entry == NULL) | |
343 | return -EINVAL; | |
344 | return list_entry->num; | |
345 | } | |
346 | ||
347 | void udev_list_entry_set_num(struct udev_list_entry *list_entry, int num) | |
348 | { | |
349 | if (list_entry == NULL) | |
350 | return; | |
351 | list_entry->num = num; | |
352 | } |