Linux 内核中链表剥离

2013年4月25日 由 Creater 留言 »

剥离后可以运行在linux与windows平台。
在用户空间编程使用linux内核链表list,hlist宏定义和操作. linux内核中的list_head和hlist_head/hlist_node是将数据结构串起来成为链表的两个重要链表构造工具。利用他们和其对应的宏定义,可以非常容易地将数据构成链表,进行链表的各种操作,和数据查询。 在内核中,这些链表操作宏定义具有通用性,和具体数据结构无关。 利用这些已有的代码,我们就不必要自己处理链表指针,而集中精力关心数据本身。

/**
 * dhlist.h
 *  - deque list and hash list from Linux Kernel
 */
#ifndef _DH_LIST_H
#define _DH_LIST_H

#ifdef typeof

static inline void prefetch(const void *x) {;}
static inline void prefetchw(const void *x) {;}

#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

#define container_of(ptr, type, member) ( { \
    const typeof( ((type *)0)->member ) *__mptr = (ptr); \
    (type *)( (char *)__mptr - offsetof(type,member) ); } )

#else

static inline int prefetch(const void *x) {;return 1;}
static inline int prefetchw(const void *x) {;return 1;}

#define offsetof(type, field)    ((LONG)(LONG_PTR)&((type *)0)->field)

#define container_of(address, type, field) \
    ((type *)((char *)(address) - offsetof(type, field)))

#endif

#ifndef LIST_POISON1
#define LIST_POISON1 ((void *) 0x00100100)
#endif

#ifndef LIST_POISON2
#define LIST_POISON2 ((void *) 0x00200200)
#endif

struct list_head
{
    struct list_head *next, *prev;
};

#define LIST_HEAD_INIT(name) { &(name), &(name) }

#define LIST_HEAD(name) \
    struct list_head name = LIST_HEAD_INIT(name)

#define INIT_LIST_HEAD(ptr) do { \
        (ptr)->next = (ptr); (ptr)->prev = (ptr); \
    } while (0)

/*
 * Insert a new entry between two known consecutive entries.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static inline void __list_add(struct list_head *_new,
                              struct list_head *prev,
                              struct list_head *next)
{
    next->prev = _new;
    _new->next = next;
    _new->prev = prev;
    prev->next = _new;
}

/**
 * list_add - add a new entry
 * @new: new entry to be added
 * @head: list head to add it after
 *
 * Insert a new entry after the specified head.
 * This is good for implementing stacks.
 */
static inline void list_add(struct list_head *_new, struct list_head *head)
{
    __list_add(_new, head, head->next);
}

/**
 * list_add_tail - add a new entry
 * @new: new entry to be added
 * @head: list head to add it before
 *
 * Insert a new entry before the specified head.
 * This is useful for implementing queues.
 */
static inline void list_add_tail(struct list_head *_new, struct list_head *head)
{
    __list_add(_new, head->prev, head);
}

static inline void __list_del(struct list_head * prev, struct list_head * next)
{
    next->prev = prev;
    prev->next = next;
}

static inline void list_del(struct list_head *entry)
{
    __list_del(entry->prev, entry->next);
    entry->next = (list_head*) LIST_POISON1;
    entry->prev = (list_head*) LIST_POISON2;
}

static inline void list_del_init(struct list_head *entry)
{
    __list_del(entry->prev, entry->next);
    INIT_LIST_HEAD(entry);
}

static inline void list_move(struct list_head *list, struct list_head *head)
{
    __list_del(list->prev, list->next);
    list_add(list, head);
}

static inline void list_move_tail(struct list_head *list, struct list_head *head)
{
    __list_del(list->prev, list->next);
    list_add_tail(list, head);
}

static inline int list_empty(const struct list_head *head)
{
    return head->next == head;
}

static inline int list_empty_careful(const struct list_head *head)
{
    struct list_head *next = head->next;
    return (next == head) && (next == head->prev);
}

static inline void __list_splice(struct list_head *list, struct list_head *head)
{
    struct list_head *first = list->next;
    struct list_head *last = list->prev;
    struct list_head *at = head->next;

    first->prev = head;
    head->next = first;

    last->next = at;
    at->prev = last;
}

/**
 * list_splice - join two lists
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 */
static inline void list_splice(struct list_head *list, struct list_head *head)
{
    if (!list_empty(list)) {
        __list_splice(list, head);
    }
}

/**
 * list_splice_init - join two lists and reinitialise the emptied list.
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 *
 * The list at @list is reinitialised
 */
static inline void list_splice_init(struct list_head *list, struct list_head *head)
{
    if (!list_empty(list)) {
        __list_splice(list, head);
        INIT_LIST_HEAD(list);
    }
}

#define list_entry(ptr, type, member) \
    container_of(ptr, type, member)

#define list_for_each(pos, head) \
    for (pos = (head)->next; prefetch(pos->next), pos != (head); \
         pos = pos->next)

#define __list_for_each(pos, head) \
    for (pos = (head)->next; pos != (head); pos = pos->next)

#define list_for_each_prev(pos, head) \
    for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
         pos = pos->prev)

#define list_for_each_safe(pos, n, head) \
    for (pos = (head)->next, n = pos->next; pos != (head); \
         pos = n, n = pos->next)

#ifdef typeof

#define list_for_each_entry(pos, head, member) \
    for (pos = list_entry((head)->next, typeof(*pos), member); \
         prefetch(pos->member.next), &pos->member != (head); \
         pos = list_entry(pos->member.next, typeof(*pos), member))

#define list_for_each_entry_reverse(pos, head, member) \
    for (pos = list_entry((head)->prev, typeof(*pos), member); \
         prefetch(pos->member.prev), &pos->member != (head); \
         pos = list_entry(pos->member.prev, typeof(*pos), member))

#define list_prepare_entry(pos, head, member) \
        ((pos) ? : list_entry(head, typeof(*pos), member))

#define list_for_each_entry_continue(pos, head, member) \
    for (pos = list_entry(pos->member.next, typeof(*pos), member); \
         prefetch(pos->member.next), &pos->member != (head); \
         pos = list_entry(pos->member.next, typeof(*pos), member))

#define list_for_each_entry_safe(pos, n, head, member) \
    for (pos = list_entry((head)->next, typeof(*pos), member), \
           n = list_entry(pos->member.next, typeof(*pos), member); \
         &pos->member != (head); \
         pos = n, n = list_entry(n->member.next, typeof(*n), member))
#else

#define list_for_each_entry(pos, typeof_pos, head, member) \
    for (pos = list_entry((head)->next, typeof_pos, member); \
         prefetch(pos->member.next), &pos->member != (head); \
         pos = list_entry(pos->member.next, typeof_pos, member))

#define list_for_each_entry_reverse(pos, typeof_pos, head, member) \
    for (pos = list_entry((head)->prev, typeof_pos, member); \
         prefetch(pos->member.prev), &pos->member != (head); \
         pos = list_entry(pos->member.prev, typeof_pos, member))

#define list_prepare_entry(pos, typeof_pos, head, member) \
        ((pos) ? : list_entry(head, typeof_pos, member))

#define list_for_each_entry_continue(pos, typeof_pos, head, member) \
    for (pos = list_entry(pos->member.next, typeof_pos, member); \
         prefetch(pos->member.next), &pos->member != (head); \
         pos = list_entry(pos->member.next, typeof_pos, member))

#define list_for_each_entry_safe(pos, typeof_pos, n, typeof_n, head, member) \
    for (pos = list_entry((head)->next, typeof_pos, member), \
           n = list_entry(pos->member.next, typeof_pos, member); \
         &pos->member != (head); \
         pos = n, n = list_entry(n->member.next, typeof_n, member))

#endif


/**
 * HASH LIST
 */
struct hlist_head {
    struct hlist_node *first;
};

struct hlist_node {
    struct hlist_node *next, **pprev;
};

#define HLIST_HEAD_INIT { .first = NULL }
#define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }
#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
#define INIT_HLIST_NODE(ptr) ((ptr)->next = NULL, (ptr)->pprev = NULL)

static inline int hlist_unhashed(const struct hlist_node *h)
{
    return !h->pprev;
}

static inline int hlist_empty(const struct hlist_head *h)
{
    return !h->first;
}

static inline void __hlist_del(struct hlist_node *n)
{
    struct hlist_node *next = n->next;
    struct hlist_node **pprev = n->pprev;
    *pprev = next;
    if (next) {
        next->pprev = pprev;
    }
}

static inline void hlist_del(struct hlist_node *n)
{
    __hlist_del(n);
    n->next = (hlist_node*) LIST_POISON1;
    n->pprev = (hlist_node**) LIST_POISON2;
}

static inline void hlist_del_init(struct hlist_node *n)
{
    if (n->pprev) {
        __hlist_del(n);
        INIT_HLIST_NODE(n);
    }
}

static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
{
    struct hlist_node *first = h->first;
    n->next = first;
    if (first) {
        first->pprev = &n->next;
    }
    h->first = n;
    n->pprev = &h->first;
}

/* next must be != NULL */
static inline void hlist_add_before(struct hlist_node *n, struct hlist_node *next)
{
    n->pprev = next->pprev;
    n->next = next;
    next->pprev = &n->next;
    *(n->pprev) = n;
}

static inline void hlist_add_after(struct hlist_node *n, struct hlist_node *next)
{
    next->next = n->next;
    n->next = next;
    next->pprev = &n->next;

    if (next->next) {
        next->next->pprev  = &next->next;
    }
}

#define hlist_entry(ptr, type, member) \
    container_of(ptr,type,member)



#ifdef typeof

#define hlist_for_each(pos, head) \
    for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
         pos = pos->next)

#define hlist_for_each_safe(pos, n, head) \
    for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
         pos = n)

#define hlist_for_each_entry(tpos, pos, head, member) \
    for (pos = (head)->first; \
         pos && ({ prefetch(pos->next); 1;}) && \
            ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
         pos = pos->next)

#define hlist_for_each_entry_continue(tpos, pos, member) \
    for (pos = (pos)->next; \
         pos && ({ prefetch(pos->next); 1;}) && \
            ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
         pos = pos->next)

#define hlist_for_each_entry_from(tpos, pos, member) \
    for (; pos && ({ prefetch(pos->next); 1;}) && \
            ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
         pos = pos->next)

#define hlist_for_each_entry_safe(tpos, pos, n, head, member) \
    for (pos = (head)->first; \
         pos && ({ n = pos->next; 1; }) && \
            ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
         pos = n)
#else

#define hlist_for_each(pos, head) \
    for (pos = (head)->first; pos && prefetch(pos->next); pos = pos->next)

#define hlist_for_each_safe(pos, n, head) \
    for (pos = (head)->first; pos && ((n=pos->next) == n); pos = n)

#define hlist_for_each_entry(tpos, typeof_tpos, pos, head, member) \
    for (pos = (head)->first; \
         pos && prefetch(pos->next) && \
           ((tpos = hlist_entry(pos, typeof_tpos, member)) == tpos); \
         pos = pos->next)

#define hlist_for_each_entry_continue(tpos, typeof_tpos, pos, member) \
    for (pos = (pos)->next; \
         pos && prefetch(pos->next) && \
            ((tpos = hlist_entry(pos, typeof_tpos, member)) == tpos); \
         pos = pos->next)

#define hlist_for_each_entry_from(tpos, typeof_tpos, pos, member) \
    for (; pos && prefetch(pos->next) && \
            ((tpos = hlist_entry(pos, typeof_tpos, member)) == tpos); \
         pos = pos->next)

#define hlist_for_each_entry_safe(tpos, typeof_tpos, pos, n, head, member) \
    for (pos = (head)->first; \
         pos && ((n = pos->next) == n) && \
            ((tpos = hlist_entry(pos, typeof_tpos, member)) == tpos); \
         pos = n)

#endif

#endif /* _DH_LIST_H */

测试程序

/**
 * test dhlist
 * cheungmine
 */
#define _CRTDBG_MAP_ALLOC     
#include<stdlib.h>  
#include<crtdbg.h>

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <memory.h>

#include <windows.h>

#include "dhlist.h"

struct ST {
    unsigned char ch;
    int  this_data;
    
  struct list_head  i_list;
    
    int  more_data;
    
  struct hlist_node i_hash;

    char str_data[32];
    int end_data;
} *st;

#define HASHSIZE 0xff
#define LISTSIZE 4096

struct list_head list1;  
struct hlist_head hlist[HASHSIZE+1];

unsigned int gethash(int c)
{
    return (c & HASHSIZE);
} 

int main()
{
    int i;
    unsigned int hash;
    struct list_head *list, *node;
    struct hlist_node *hp;
    struct hlist_node *hn;

    INIT_LIST_HEAD(&list1);

    for (hash = 0; hash <= HASHSIZE; hash++) {
        INIT_HLIST_HEAD(&hlist[hash]);
    }

    for(i = 0; i < LISTSIZE; i++) {
        struct ST *p = (ST*) malloc(sizeof(*p));
        if(!p) {
            printf("malloc failed.\n");
            break;
        }

        p->ch = 'a' + i;
        sprintf(p->str_data, "data:%d", i);

        // 串入长串
        list_add(&p->i_list, &list1);

        // 串入HASH短串
        hash = gethash(p->ch);

        printf("ALLOC %x %d %p %u\n", p->ch, i, p, hash);

        if (hash > HASHSIZE) {
          printf("**********ERROR**********\n");
        } else {
          hlist_add_head(&p->i_hash, &hlist[hash]);
        }
    }

    // 通过长铁丝遍历
    i = 0; 
    list_for_each(list, &list1) {
        struct ST *p = list_entry(list, struct ST, i_list);
        printf("%p  value %d = %d\n", p, i, (int)p->ch);
        i++;
    }
    printf("total %d \n", i);

    printf("通过hash串查找内容'C'的箱子\n");
    hash = gethash('c');
    hlist_for_each(hp, &hlist[hash]) {
        struct ST *p = hlist_entry(hp, struct ST, i_hash);
        printf("hlist: %c\n", p->ch);
    }

    printf("通过hash串查找内容'C'的箱子并删除之\n");
    hlist_for_each_safe(hp, hn, &hlist[hash]) {
        struct ST *p = hlist_entry(hp, struct ST, i_hash);
        printf("hlist_del: %c; %s\n", p->ch, p->str_data);
        hlist_del(hp);
    }

    printf("通过hash串查找内容'C'的箱子\n");
    hlist_for_each(hp, &hlist[hash]) {
        struct ST *p = hlist_entry(hp, struct ST, i_hash);
        printf("hlist: %c\n", p->ch);
    }

    printf("删除全部节点箱子\n");
    list_for_each_safe(list, node, &list1) {
        struct ST *p = list_entry(list, struct ST, i_list);
        list_del(list);
        free(p);
    }

    // 检测内存泄露
    _CrtDumpMemoryLeaks();
    return 0;
}

参考文献
http://www.chinaunix.net/old_jh/23/941100.html

http://linux.chinaunix.net/techdoc/system/2007/12/28/975345.shtml

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