forked from Mirror/frr
acdf5e2510
list_free is occassionally being used to delete the list and accidently not deleting all the nodes. We keep running across this usage pattern. Let's remove the temptation and only allow list_delete to handle list deletion. Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
157 lines
6.2 KiB
C
157 lines
6.2 KiB
C
/* Generic linked list
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* Copyright (C) 1997, 2000 Kunihiro Ishiguro
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*
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* This file is part of GNU Zebra.
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*
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* GNU Zebra is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* GNU Zebra is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; see the file COPYING; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _ZEBRA_LINKLIST_H
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#define _ZEBRA_LINKLIST_H
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/* listnodes must always contain data to be valid. Adding an empty node
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* to a list is invalid
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*/
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struct listnode {
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struct listnode *next;
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struct listnode *prev;
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/* private member, use getdata() to retrieve, do not access directly */
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void *data;
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};
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struct list {
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struct listnode *head;
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struct listnode *tail;
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/* invariant: count is the number of listnodes in the list */
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unsigned int count;
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/*
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* Returns -1 if val1 < val2, 0 if equal?, 1 if val1 > val2.
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* Used as definition of sorted for listnode_add_sort
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*/
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int (*cmp)(void *val1, void *val2);
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/* callback to free user-owned data when listnode is deleted. supplying
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* this callback is very much encouraged!
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*/
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void (*del)(void *val);
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};
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#define listnextnode(X) ((X) ? ((X)->next) : NULL)
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#define listhead(X) ((X) ? ((X)->head) : NULL)
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#define listtail(X) ((X) ? ((X)->tail) : NULL)
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#define listcount(X) ((X)->count)
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#define list_isempty(X) ((X)->head == NULL && (X)->tail == NULL)
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#define listgetdata(X) (assert((X)->data != NULL), (X)->data)
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/* Prototypes. */
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extern struct list *
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list_new(void); /* encouraged: set list.del callback on new lists */
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extern void listnode_add(struct list *, void *);
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extern void listnode_add_sort(struct list *, void *);
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extern struct listnode *listnode_add_after(struct list *, struct listnode *,
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void *);
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extern struct listnode *listnode_add_before(struct list *, struct listnode *,
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void *);
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extern void listnode_move_to_tail(struct list *, struct listnode *);
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extern void listnode_delete(struct list *, void *);
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extern struct listnode *listnode_lookup(struct list *, void *);
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extern void *listnode_head(struct list *);
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/*
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* The usage of list_delete is being transitioned to pass in
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* the double pointer to remove use after free's.
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* list_free usage is deprecated, it leads to memory leaks
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* of the linklist nodes. Please use list_delete_and_null
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*
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* In Oct of 2018, rename list_delete_and_null to list_delete
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* and remove list_delete_original and the list_delete #define
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* Additionally remove list_free entirely
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*/
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#if CONFDATE > 20181001
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CPP_NOTICE("list_delete without double pointer is deprecated, please fixup")
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#endif
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extern void list_delete_and_null(struct list **);
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extern void list_delete_original(struct list *);
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#define list_delete(X) list_delete_original((X)) \
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CPP_WARN("Please transition to using list_delete_and_null")
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#define list_free(X) list_delete_original((X)) \
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CPP_WARN("Please transition tousing list_delete_and_null")
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extern void list_delete_all_node(struct list *);
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/* For ospfd and ospf6d. */
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extern void list_delete_node(struct list *, struct listnode *);
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/* For ospf_spf.c */
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extern void list_add_list(struct list *, struct list *);
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/* List iteration macro.
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* Usage: for (ALL_LIST_ELEMENTS (...) { ... }
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* It is safe to delete the listnode using this macro.
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*/
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#define ALL_LIST_ELEMENTS(list, node, nextnode, data) \
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(node) = listhead(list), ((data) = NULL); \
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(node) != NULL \
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&& ((data) = listgetdata(node), (nextnode) = node->next, 1); \
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(node) = (nextnode), ((data) = NULL)
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/* read-only list iteration macro.
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* Usage: as per ALL_LIST_ELEMENTS, but not safe to delete the listnode Only
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* use this macro when it is *immediately obvious* the listnode is not
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* deleted in the body of the loop. Does not have forward-reference overhead
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* of previous macro.
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*/
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#define ALL_LIST_ELEMENTS_RO(list, node, data) \
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(node) = listhead(list), ((data) = NULL); \
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(node) != NULL && ((data) = listgetdata(node), 1); \
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(node) = listnextnode(node), ((data) = NULL)
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/* these *do not* cleanup list nodes and referenced data, as the functions
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* do - these macros simply {de,at}tach a listnode from/to a list.
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*/
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/* List node attach macro. */
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#define LISTNODE_ATTACH(L, N) \
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do { \
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(N)->prev = (L)->tail; \
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(N)->next = NULL; \
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if ((L)->head == NULL) \
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(L)->head = (N); \
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else \
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(L)->tail->next = (N); \
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(L)->tail = (N); \
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(L)->count++; \
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} while (0)
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/* List node detach macro. */
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#define LISTNODE_DETACH(L, N) \
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do { \
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if ((N)->prev) \
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(N)->prev->next = (N)->next; \
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else \
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(L)->head = (N)->next; \
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if ((N)->next) \
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(N)->next->prev = (N)->prev; \
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else \
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(L)->tail = (N)->prev; \
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(L)->count--; \
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} while (0)
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#endif /* _ZEBRA_LINKLIST_H */
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