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嘿, 我想用sysfs稍微玩一下,從用戶空間獲取一些數據到我的內核模塊中。 下面是代碼:從內核模塊使用sysfs時出現未知的符號錯誤
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/elf.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#define PRINT(x) printk(KERN_INFO x "\n")
#define ERROR(fmt,arg...) printk(KERN_ALERT "Error - " fmt,##arg)
ssize_t mystore (struct kobject *obj,
struct attribute *attr, const char *buff, size_t count)
{
/* doing a little bit */
return count;
}
ssize_t myshow (struct kobject *obj, struct attribute *attr, char *buff)
{
return 0;
}
char file_name[] = "myfile";
static struct attribute myattribute = {
.name = file_name,
.mode = S_IRUSR | S_IWUSR
};
static struct sysfs_ops mysysfs_ops = {
.show = myshow,
.store = mystore
};
static struct kobj_type mykobj_type = {
.sysfs_ops = &mysysfs_ops,
};
static struct kobject mykobject = {
.name = "mykobject",
.ktype = &mykobj_type
};
static int __init start(void)
{
int tmp;
PRINT("Initializing module\n");
if (kobject_init_and_add(&mykobject, &mykobj_type, NULL, "mykobj") != 0) {
ERROR ("Digsig key failed to register properly\n");
return -1;
}
if ((tmp = sysfs_create_file(&mykobject, &myattribute)) != 0) {
ERROR ("Create file failed\n");
return -1;
}
PRINT("INIT CORRECT");
return 0;
}
static void __exit close(void)
{
PRINT("Deinitializing module\n");
sysfs_remove_file(&mykobject, &myattribute);
kobject_del(&mykobject);
}
module_init(start);
module_exit(close);
當我編譯我的模塊,一切工作正常,但是當我嘗試運行它,我得到一個 insmod的:錯誤插入「mytester.ko」:-1模塊未知符號
用dmesg我得到更多的細節:
[18335.892462] mytester: Unknown symbol sysfs_remove_file (err 0)
[18335.892462] mytester: Unknown symbol sysfs_create_file (err 0)
[18335.892646] mytester: Unknown symbol kobject_init_and_add (err 0)
而這就是問題所在。我不明白這個消息,因爲包括kobject.h和sysfs.h。所以我不能真正理解這裏發生的事情。即使我將我的整個函數mystore註釋爲簡單返回(如圖所示),錯誤也是一樣的。所以錯誤不在其他地方......
謝謝,因爲我剛剛瞭解這一點,我沒有照顧這樣的事情obv :) 但除此之外:任何人都可以看到代碼中的錯誤(尤其是kobject和sysfil創建)?因爲現在它會被段錯誤(可能是在kobject_init_and_add調用中)殺死 – michael 2011-03-04 14:45:46