libudev-list.c revision 29804cc1e0f37ee34301530fd7f1eb8550be464e
/***
This file is part of systemd.
Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include "libudev.h"
#include "libudev-private.h"
/**
* SECTION:libudev-list
* @short_description: list operation
*
* Libudev list operations.
*/
/**
* udev_list_entry:
*
* Opaque object representing one entry in a list. An entry contains
* contains a name, and optionally a value.
*/
struct udev_list_entry {
struct udev_list_node node;
struct udev_list *list;
char *name;
char *value;
int num;
};
/* the list's head points to itself if empty */
void udev_list_node_init(struct udev_list_node *list)
{
list->next = list;
list->prev = list;
}
int udev_list_node_is_empty(struct udev_list_node *list)
{
return list->next == list;
}
static void udev_list_node_insert_between(struct udev_list_node *new,
struct udev_list_node *prev,
struct udev_list_node *next)
{
next->prev = new;
new->next = next;
new->prev = prev;
prev->next = new;
}
void udev_list_node_append(struct udev_list_node *new, struct udev_list_node *list)
{
udev_list_node_insert_between(new, list->prev, list);
}
void udev_list_node_remove(struct udev_list_node *entry)
{
struct udev_list_node *prev = entry->prev;
struct udev_list_node *next = entry->next;
next->prev = prev;
prev->next = next;
entry->prev = NULL;
entry->next = NULL;
}
/* return list entry which embeds this node */
static inline struct udev_list_entry *list_node_to_entry(struct udev_list_node *node)
{
return container_of(node, struct udev_list_entry, node);
}
void udev_list_init(struct udev *udev, struct udev_list *list, bool unique)
{
memzero(list, sizeof(struct udev_list));
list->udev = udev;
list->unique = unique;
udev_list_node_init(&list->node);
}
/* insert entry into a list as the last element */
static void udev_list_entry_append(struct udev_list_entry *new, struct udev_list *list)
{
/* inserting before the list head make the node the last node in the list */
udev_list_node_insert_between(&new->node, list->node.prev, &list->node);
new->list = list;
}
/* insert entry into a list, before a given existing entry */
static void udev_list_entry_insert_before(struct udev_list_entry *new, struct udev_list_entry *entry)
{
udev_list_node_insert_between(&new->node, entry->node.prev, &entry->node);
new->list = entry->list;
}
/* binary search in sorted array */
static int list_search(struct udev_list *list, const char *name)
{
unsigned int first, last;
first = 0;
last = list->entries_cur;
while (first < last) {
unsigned int i;
int cmp;
i = (first + last)/2;
cmp = strcmp(name, list->entries[i]->name);
if (cmp < 0)
last = i;
else if (cmp > 0)
first = i+1;
else
return i;
}
/* not found, return negative insertion-index+1 */
return -(first+1);
}
struct udev_list_entry *udev_list_entry_add(struct udev_list *list, const char *name, const char *value)
{
struct udev_list_entry *entry;
int i = 0;
if (list->unique) {
/* lookup existing name or insertion-index */
i = list_search(list, name);
if (i >= 0) {
entry = list->entries[i];
free(entry->value);
if (value == NULL) {
entry->value = NULL;
return entry;
}
entry->value = strdup(value);
if (entry->value == NULL)
return NULL;
return entry;
}
}
/* add new name */
entry = calloc(1, sizeof(struct udev_list_entry));
if (entry == NULL)
return NULL;
entry->name = strdup(name);
if (entry->name == NULL) {
free(entry);
return NULL;
}
if (value != NULL) {
entry->value = strdup(value);
if (entry->value == NULL) {
free(entry->name);
free(entry);
return NULL;
}
}
if (list->unique) {
/* allocate or enlarge sorted array if needed */
if (list->entries_cur >= list->entries_max) {
struct udev_list_entry **entries;
unsigned int add;
add = list->entries_max;
if (add < 1)
add = 64;
entries = realloc(list->entries, (list->entries_max + add) * sizeof(struct udev_list_entry *));
if (entries == NULL) {
free(entry->name);
free(entry->value);
free(entry);
return NULL;
}
list->entries = entries;
list->entries_max += add;
}
/* the negative i returned the insertion index */
i = (-i)-1;
/* insert into sorted list */
if ((unsigned int)i < list->entries_cur)
udev_list_entry_insert_before(entry, list->entries[i]);
else
udev_list_entry_append(entry, list);
/* insert into sorted array */
memmove(&list->entries[i+1], &list->entries[i],
(list->entries_cur - i) * sizeof(struct udev_list_entry *));
list->entries[i] = entry;
list->entries_cur++;
} else {
udev_list_entry_append(entry, list);
}
return entry;
}
void udev_list_entry_delete(struct udev_list_entry *entry)
{
if (entry->list->entries != NULL) {
int i;
struct udev_list *list = entry->list;
/* remove entry from sorted array */
i = list_search(list, entry->name);
if (i >= 0) {
memmove(&list->entries[i], &list->entries[i+1],
((list->entries_cur-1) - i) * sizeof(struct udev_list_entry *));
list->entries_cur--;
}
}
udev_list_node_remove(&entry->node);
free(entry->name);
free(entry->value);
free(entry);
}
void udev_list_cleanup(struct udev_list *list)
{
struct udev_list_entry *entry_loop;
struct udev_list_entry *entry_tmp;
free(list->entries);
list->entries = NULL;
list->entries_cur = 0;
list->entries_max = 0;
udev_list_entry_foreach_safe(entry_loop, entry_tmp, udev_list_get_entry(list))
udev_list_entry_delete(entry_loop);
}
struct udev_list_entry *udev_list_get_entry(struct udev_list *list)
{
if (udev_list_node_is_empty(&list->node))
return NULL;
return list_node_to_entry(list->node.next);
}
/**
* udev_list_entry_get_next:
* @list_entry: current entry
*
* Get the next entry from the list.
*
* Returns: udev_list_entry, #NULL if no more entries are available.
*/
_public_ struct udev_list_entry *udev_list_entry_get_next(struct udev_list_entry *list_entry)
{
struct udev_list_node *next;
if (list_entry == NULL)
return NULL;
next = list_entry->node.next;
/* empty list or no more entries */
if (next == &list_entry->list->node)
return NULL;
return list_node_to_entry(next);
}
/**
* udev_list_entry_get_by_name:
* @list_entry: current entry
* @name: name string to match
*
* Lookup an entry in the list with a certain name.
*
* Returns: udev_list_entry, #NULL if no matching entry is found.
*/
_public_ struct udev_list_entry *udev_list_entry_get_by_name(struct udev_list_entry *list_entry, const char *name)
{
int i;
if (list_entry == NULL)
return NULL;
if (!list_entry->list->unique)
return NULL;
i = list_search(list_entry->list, name);
if (i < 0)
return NULL;
return list_entry->list->entries[i];
}
/**
* udev_list_entry_get_name:
* @list_entry: current entry
*
* Get the name of a list entry.
*
* Returns: the name string of this entry.
*/
_public_ const char *udev_list_entry_get_name(struct udev_list_entry *list_entry)
{
if (list_entry == NULL)
return NULL;
return list_entry->name;
}
/**
* udev_list_entry_get_value:
* @list_entry: current entry
*
* Get the value of list entry.
*
* Returns: the value string of this entry.
*/
_public_ const char *udev_list_entry_get_value(struct udev_list_entry *list_entry)
{
if (list_entry == NULL)
return NULL;
return list_entry->value;
}
int udev_list_entry_get_num(struct udev_list_entry *list_entry)
{
if (list_entry == NULL)
return -EINVAL;
return list_entry->num;
}
void udev_list_entry_set_num(struct udev_list_entry *list_entry, int num)
{
if (list_entry == NULL)
return;
list_entry->num = num;
}