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git.ipfire.org Git - thirdparty/systemd.git/blob - src/libudev/libudev-list.c
1 /* SPDX-License-Identifier: LGPL-2.1+ */
8 #include "alloc-util.h"
9 #include "libudev-list-internal.h"
13 * SECTION:libudev-list
14 * @short_description: list operation
16 * Libudev list operations.
22 * Opaque object representing one entry in a list. An entry contains
23 * contains a name, and optionally a value.
25 struct udev_list_entry
{
26 struct udev_list_node node
;
27 struct udev_list
*list
;
33 /* the list's head points to itself if empty */
34 static void udev_list_node_init(struct udev_list_node
*list
) {
39 static int udev_list_node_is_empty(struct udev_list_node
*list
) {
40 return list
->next
== list
;
43 static void udev_list_node_insert_between(struct udev_list_node
*new,
44 struct udev_list_node
*prev
,
45 struct udev_list_node
*next
) {
52 static void udev_list_node_remove(struct udev_list_node
*entry
) {
53 struct udev_list_node
*prev
= entry
->prev
;
54 struct udev_list_node
*next
= entry
->next
;
63 /* return list entry which embeds this node */
64 static inline struct udev_list_entry
*list_node_to_entry(struct udev_list_node
*node
) {
65 return container_of(node
, struct udev_list_entry
, node
);
68 void udev_list_init(struct udev
*udev
, struct udev_list
*list
, bool unique
) {
69 memzero(list
, sizeof(struct udev_list
));
71 list
->unique
= unique
;
72 udev_list_node_init(&list
->node
);
75 /* insert entry into a list as the last element */
76 static void udev_list_entry_append(struct udev_list_entry
*new, struct udev_list
*list
) {
77 /* inserting before the list head make the node the last node in the list */
78 udev_list_node_insert_between(&new->node
, list
->node
.prev
, &list
->node
);
82 /* insert entry into a list, before a given existing entry */
83 static void udev_list_entry_insert_before(struct udev_list_entry
*new, struct udev_list_entry
*entry
) {
84 udev_list_node_insert_between(&new->node
, entry
->node
.prev
, &entry
->node
);
85 new->list
= entry
->list
;
88 /* binary search in sorted array */
89 static int list_search(struct udev_list
*list
, const char *name
) {
93 last
= list
->entries_cur
;
94 while (first
< last
) {
99 cmp
= strcmp(name
, list
->entries
[i
]->name
);
108 /* not found, return negative insertion-index+1 */
112 struct udev_list_entry
*udev_list_entry_add(struct udev_list
*list
, const char *name
, const char *value
) {
113 struct udev_list_entry
*entry
;
117 /* lookup existing name or insertion-index */
118 i
= list_search(list
, name
);
120 entry
= list
->entries
[i
];
127 entry
->value
= strdup(value
);
135 entry
= new0(struct udev_list_entry
, 1);
139 entry
->name
= strdup(name
);
144 entry
->value
= strdup(value
);
152 /* allocate or enlarge sorted array if needed */
153 if (list
->entries_cur
>= list
->entries_max
) {
154 struct udev_list_entry
**entries
;
157 add
= list
->entries_max
;
160 entries
= reallocarray(list
->entries
, list
->entries_max
+ add
, sizeof(struct udev_list_entry
*));
166 list
->entries
= entries
;
167 list
->entries_max
+= add
;
170 /* the negative i returned the insertion index */
173 /* insert into sorted list */
174 if ((unsigned)i
< list
->entries_cur
)
175 udev_list_entry_insert_before(entry
, list
->entries
[i
]);
177 udev_list_entry_append(entry
, list
);
179 /* insert into sorted array */
180 memmove(&list
->entries
[i
+1], &list
->entries
[i
],
181 (list
->entries_cur
- i
) * sizeof(struct udev_list_entry
*));
182 list
->entries
[i
] = entry
;
185 udev_list_entry_append(entry
, list
);
190 static void udev_list_entry_delete(struct udev_list_entry
*entry
) {
191 if (entry
->list
->entries
) {
193 struct udev_list
*list
= entry
->list
;
195 /* remove entry from sorted array */
196 i
= list_search(list
, entry
->name
);
198 memmove(&list
->entries
[i
], &list
->entries
[i
+1],
199 ((list
->entries_cur
-1) - i
) * sizeof(struct udev_list_entry
*));
204 udev_list_node_remove(&entry
->node
);
210 #define udev_list_entry_foreach_safe(entry, tmp, first) \
211 for (entry = first, tmp = udev_list_entry_get_next(entry); \
213 entry = tmp, tmp = udev_list_entry_get_next(tmp))
215 void udev_list_cleanup(struct udev_list
*list
) {
216 struct udev_list_entry
*entry_loop
;
217 struct udev_list_entry
*entry_tmp
;
219 list
->entries
= mfree(list
->entries
);
220 list
->entries_cur
= 0;
221 list
->entries_max
= 0;
222 udev_list_entry_foreach_safe(entry_loop
, entry_tmp
, udev_list_get_entry(list
))
223 udev_list_entry_delete(entry_loop
);
226 struct udev_list_entry
*udev_list_get_entry(struct udev_list
*list
) {
227 if (udev_list_node_is_empty(&list
->node
))
229 return list_node_to_entry(list
->node
.next
);
233 * udev_list_entry_get_next:
234 * @list_entry: current entry
236 * Get the next entry from the list.
238 * Returns: udev_list_entry, #NULL if no more entries are available.
240 _public_
struct udev_list_entry
*udev_list_entry_get_next(struct udev_list_entry
*list_entry
) {
241 struct udev_list_node
*next
;
245 next
= list_entry
->node
.next
;
246 /* empty list or no more entries */
247 if (next
== &list_entry
->list
->node
)
249 return list_node_to_entry(next
);
253 * udev_list_entry_get_by_name:
254 * @list_entry: current entry
255 * @name: name string to match
257 * Lookup an entry in the list with a certain name.
259 * Returns: udev_list_entry, #NULL if no matching entry is found.
261 _public_
struct udev_list_entry
*udev_list_entry_get_by_name(struct udev_list_entry
*list_entry
, const char *name
) {
267 if (!list_entry
->list
->unique
)
270 i
= list_search(list_entry
->list
, name
);
273 return list_entry
->list
->entries
[i
];
277 * udev_list_entry_get_name:
278 * @list_entry: current entry
280 * Get the name of a list entry.
282 * Returns: the name string of this entry.
284 _public_
const char *udev_list_entry_get_name(struct udev_list_entry
*list_entry
) {
287 return list_entry
->name
;
291 * udev_list_entry_get_value:
292 * @list_entry: current entry
294 * Get the value of list entry.
296 * Returns: the value string of this entry.
298 _public_
const char *udev_list_entry_get_value(struct udev_list_entry
*list_entry
) {
301 return list_entry
->value
;
304 int udev_list_entry_get_num(struct udev_list_entry
*list_entry
) {
307 return list_entry
->num
;
310 void udev_list_entry_set_num(struct udev_list_entry
*list_entry
, int num
) {
313 list_entry
->num
= num
;