Linux kernel linked list for user space

We can use Linux kernel linked list for user space with a very small modifications. It's a single header file. very handy!

Here is a recipe to fix list.h for user space program.

1. Get linux/include/list.h
2. Remove
   • #ifdef __KERNE__ and its #endif
   • all #include line
   • prefetch(something)
   • rcu related functions(many of them there)
3. Add
   • A macro offsetof()
   • A macro container_of()

You can get a modified header file(list.h) from here.

A sample program

#include <stdio.h> #include <stdlib.h> #include "list.h" struct a_list { struct list_head list; int val; const char* str; }; static void append(struct a_list* ptr,const char* str, int val) { struct a_list* tmp; tmp = (struct a_list*)malloc(sizeof(struct a_list)); if(!tmp) { perror("malloc"); exit(1); } tmp->str = str; tmp->val = val; list_add_tail( &(tmp->list), &(ptr->list) ); } int main() { struct a_list blist; struct a_list* iter; INIT_LIST_HEAD(&blist.list); /* add item to list */ append(&blist, "NM", 87501); append(&blist, "CA", 94041); append(&blist, "IL", 60561); /* iterates list */ list_for_each_entry(iter,&blist.list,list) { printf("%s %d\n", iter->str, iter->val); } /* remove all items in the list */ while( !list_empty(&blist.list) ) { iter = list_entry(blist.list.next,struct a_list,list); list_del(&iter->list); free(iter); } return 0; }