Un petit exemple de note de list_head

supposition

ubuntu# uname -a
Linux ubuntu 4.4.0-93-generic #116-Ubuntu SMP Fri Aug 11 21:17:51 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
ubuntu# cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.3 LTS"

Je ne sais pas comment cela fonctionne, alors j'y reviendrai plus tard. Pour le moment, j'ai lu le code Linux et je ne l'ai pas bien compris, donc j'ai pris note uniquement du code de travail minimum (pas de traitement de libération de mémoire).

code

kure.c

#include <linux/module.h>       /* MODULE, THIS_MODULE */
#include <linux/moduleparam.h>
#include <linux/kernel.h>       /* printk() */
#include <linux/errno.h>        /* error codes */
#include <linux/list.h>         /* list_*() */
#include <linux/slab.h>         /* kmalloc() */

MODULE_AUTHOR("kuredev");
MODULE_LICENSE("Dual BSD/GPL");

struct kurest
{
        int no;
        struct list_head list_head_;
};

struct kurest data1 = {
        .no = -1,
};

static int kure_init(void)
{
        printk(KERN_ALERT "Listtest init\n");
        struct kurest *data2, *data3;
        struct list_head *ptr;
        struct kurest *entry;
        INIT_LIST_HEAD(&data1.list_head_);

        data2 = kmalloc(sizeof(struct kurest), GFP_KERNEL);
        data2->no = 2;
        list_add(&data2->list_head_, &data1.list_head_);

        data3 = kmalloc(sizeof(struct kurest), GFP_KERNEL);
        data3->no = 3;
        list_add(&data3->list_head_, &data1.list_head_);

        list_for_each(ptr, &data1.list_head_){
                 entry = list_entry(ptr, struct kurest, list_head_);
                 printk("no: %d\n", entry->no);
        }

        return 0;
}


static void kure_exit(void)
{
        printk(KERN_ALERT "Listtest exit\n");
}

module_init(kure_init);
module_exit(kure_exit);

Makefile

KERNEL_DIR = /lib/modules/$(shell uname -r)/build
BUILD_DIR := $(shell pwd)
VERBOSE   := 0
obj-m := kure.o
all:
        make -C $(KERNEL_DIR) SUBDIRS=$(BUILD_DIR) KBUILD_VERBOSE=$(VERBOSE) modules
clean:
        rm -rf  *.o *.ko *.mod.c *.symvers *.order .tmp_versions .kure.*

Courir

# make
# insmod kure.ko
# tail /var/log/syslog
Sep 18 23:12:16 ubuntu kernel: [23064.945863] Listtest init
Sep 18 23:12:16 ubuntu kernel: [23064.945869] no: 3
Sep 18 23:12:16 ubuntu kernel: [23064.945870] no: 2
Sep 18 23:12:21 ubuntu kernel: [23069.543457] Listtest exit

référence

Comment utiliser la liste fournie par le noyau Linux - le journal de mmitou http://d.hatena.ne.jp/mmitou/20120626/1340731801