forked from Qortal/Brooklyn
2a709f28fa
* 0day explit mitigation * Memory corruption prevention * Privilege escalation prevention * Buffer over flow prevention * File System corruption defense * Thread escape prevention This may very well be the most intensive inclusion to BrooklynR. This will not be part of an x86 suite nor it will be released as tool kit. The security core toolkit will remain part of kernel base.
118 lines
3.2 KiB
C
118 lines
3.2 KiB
C
#ifndef _LINUX_LIST_NULLS_H
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#define _LINUX_LIST_NULLS_H
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#include <linux/poison.h>
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#include <linux/const.h>
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/*
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* Special version of lists, where end of list is not a NULL pointer,
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* but a 'nulls' marker, which can have many different values.
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* (up to 2^31 different values guaranteed on all platforms)
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*
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* In the standard hlist, termination of a list is the NULL pointer.
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* In this special 'nulls' variant, we use the fact that objects stored in
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* a list are aligned on a word (4 or 8 bytes alignment).
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* We therefore use the last significant bit of 'ptr' :
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* Set to 1 : This is a 'nulls' end-of-list marker (ptr >> 1)
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* Set to 0 : This is a pointer to some object (ptr)
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*/
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struct hlist_nulls_head {
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struct hlist_nulls_node *first;
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};
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struct hlist_nulls_node {
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struct hlist_nulls_node *next, **pprev;
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};
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#define NULLS_MARKER(value) (1UL | (((long)value) << 1))
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#define INIT_HLIST_NULLS_HEAD(ptr, nulls) \
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((ptr)->first = (struct hlist_nulls_node *) NULLS_MARKER(nulls))
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#define hlist_nulls_entry(ptr, type, member) container_of(ptr,type,member)
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/**
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* ptr_is_a_nulls - Test if a ptr is a nulls
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* @ptr: ptr to be tested
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*
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*/
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static inline int is_a_nulls(const struct hlist_nulls_node *ptr)
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{
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return ((unsigned long)ptr & 1);
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}
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/**
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* get_nulls_value - Get the 'nulls' value of the end of chain
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* @ptr: end of chain
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*
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* Should be called only if is_a_nulls(ptr);
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*/
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static inline unsigned long get_nulls_value(const struct hlist_nulls_node *ptr)
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{
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return ((unsigned long)ptr) >> 1;
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}
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static inline int hlist_nulls_unhashed(const struct hlist_nulls_node *h)
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{
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return !h->pprev;
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}
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static inline int hlist_nulls_empty(const struct hlist_nulls_head *h)
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{
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return is_a_nulls(READ_ONCE(h->first));
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}
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static inline void hlist_nulls_add_head(struct hlist_nulls_node *n,
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struct hlist_nulls_head *h)
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{
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struct hlist_nulls_node *first = h->first;
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n->next = first;
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n->pprev = &h->first;
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h->first = n;
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if (!is_a_nulls(first))
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first->pprev = &n->next;
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}
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static inline void __hlist_nulls_del(struct hlist_nulls_node *n)
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{
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struct hlist_nulls_node *next = n->next;
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struct hlist_nulls_node **pprev = n->pprev;
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WRITE_ONCE(*pprev, next);
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if (!is_a_nulls(next))
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next->pprev = pprev;
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}
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static inline void hlist_nulls_del(struct hlist_nulls_node *n)
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{
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__hlist_nulls_del(n);
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n->pprev = LIST_POISON2;
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}
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/**
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* hlist_nulls_for_each_entry - iterate over list of given type
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* @tpos: the type * to use as a loop cursor.
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* @pos: the &struct hlist_node to use as a loop cursor.
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* @head: the head for your list.
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* @member: the name of the hlist_node within the struct.
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*
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*/
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#define hlist_nulls_for_each_entry(tpos, pos, head, member) \
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for (pos = (head)->first; \
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(!is_a_nulls(pos)) && \
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({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1;}); \
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pos = pos->next)
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/**
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* hlist_nulls_for_each_entry_from - iterate over a hlist continuing from current point
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* @tpos: the type * to use as a loop cursor.
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* @pos: the &struct hlist_node to use as a loop cursor.
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* @member: the name of the hlist_node within the struct.
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*
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*/
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#define hlist_nulls_for_each_entry_from(tpos, pos, member) \
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for (; (!is_a_nulls(pos)) && \
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({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1;}); \
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pos = pos->next)
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#endif
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