/* * 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_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) { memset(list, 0x00, 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 */ 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 */ 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) { unsigned int add; add = list->entries_max; if (add < 1) add = 64; list->entries = realloc(list->entries, (list->entries_max + add) * sizeof(struct udev_list_entry *)); if (list->entries == NULL) { free(entry->name); free(entry->value); return NULL; } 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; }