libudev-list.c revision 666fcf03bceea8e8dd6c4510220036d1b949b814
/*
* libudev - interface to udev device information
*
* Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
*
* This library 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.
*/
#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 *udev;
struct udev_list_node *list;
char *name;
char *value;
int num;
};
/* the list's head points to itself if empty */
void udev_list_init(struct udev_list_node *list)
{
list->next = list;
list->prev = list;
}
int udev_list_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 struct udev_list_entry *list_node_to_entry(struct udev_list_node *node)
{
char *list;
list = (char *)node;
list -= offsetof(struct udev_list_entry, node);
return (struct udev_list_entry *)list;
}
/* insert entry into a list as the last element */
void udev_list_entry_append(struct udev_list_entry *new, struct udev_list_node *list)
{
/* inserting before the list head make the node the last node in the list */
udev_list_node_insert_between(&new->node, list->prev, list);
new->list = list;
}
/* remove entry from a list */
void udev_list_entry_remove(struct udev_list_entry *entry)
{
udev_list_node_remove(&entry->node);
entry->list = NULL;
}
/* insert entry into a list, before a given existing entry */
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;
}
struct udev_list_entry *udev_list_entry_add(struct udev *udev, struct udev_list_node *list,
const char *name, const char *value,
unsigned int flags)
{
struct udev_list_entry *entry_loop = NULL;
struct udev_list_entry *entry_new;
if (flags & UDEV_LIST_UNIQUE) {
udev_list_entry_foreach(entry_loop, udev_list_get_entry(list)) {
if (strcmp(entry_loop->name, name) == 0) {
dbg(udev, "'%s' is already in the list\n", name);
free(entry_loop->value);
if (value == NULL) {
entry_loop->value = NULL;
dbg(udev, "'%s' value unset\n", name);
return entry_loop;
}
entry_loop->value = strdup(value);
if (entry_loop->value == NULL)
return NULL;
dbg(udev, "'%s' value replaced with '%s'\n", name, value);
return entry_loop;
}
}
}
if (flags & UDEV_LIST_SORT) {
udev_list_entry_foreach(entry_loop, udev_list_get_entry(list)) {
if (strcmp(entry_loop->name, name) > 0)
break;
}
}
entry_new = malloc(sizeof(struct udev_list_entry));
if (entry_new == NULL)
return NULL;
memset(entry_new, 0x00, sizeof(struct udev_list_entry));
entry_new->udev = udev;
entry_new->name = strdup(name);
if (entry_new->name == NULL) {
free(entry_new);
return NULL;
}
if (value != NULL) {
entry_new->value = strdup(value);
if (entry_new->value == NULL) {
free(entry_new->name);
free(entry_new);
return NULL;
}
}
if (entry_loop != NULL)
udev_list_entry_insert_before(entry_new, entry_loop);
else
udev_list_entry_append(entry_new, list);
dbg(udev, "'%s=%s' added\n", entry_new->name, entry_new->value);
return entry_new;
}
void udev_list_entry_delete(struct udev_list_entry *entry)
{
udev_list_node_remove(&entry->node);
free(entry->name);
free(entry->value);
free(entry);
}
void udev_list_cleanup_entries(struct udev *udev, struct udev_list_node *list)
{
struct udev_list_entry *entry_loop;
struct udev_list_entry *entry_tmp;
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_node *list)
{
if (udev_list_is_empty(list))
return NULL;
return list_node_to_entry(list->next);
}
/**
* udev_list_entry_get_next:
* @list_entry: current entry
*
* Returns: the next entry from the list, #NULL is no more entries are found.
*/
UDEV_EXPORT 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)
return NULL;
return list_node_to_entry(next);
}
/**
* udev_list_entry_get_by_name:
* @list_entry: current entry
* @name: name string to match
*
* Returns: the entry where @name matched, #NULL if no matching entry is found.
*/
UDEV_EXPORT struct udev_list_entry *udev_list_entry_get_by_name(struct udev_list_entry *list_entry, const char *name)
{
struct udev_list_entry *entry;
udev_list_entry_foreach(entry, list_entry) {
if (strcmp(udev_list_entry_get_name(entry), name) == 0) {
dbg(entry->udev, "found '%s=%s'\n", entry->name, entry->value);
return entry;
}
}
return NULL;
}
/**
* udev_list_entry_get_name:
* @list_entry: current entry
*
* Returns: the name string of this entry.
*/
UDEV_EXPORT 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
*
* Returns: the value string of this entry.
*/
UDEV_EXPORT 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;
}