Question

我写了一个linux模块来创建一个proc文件并从中写入和读取数据。但我无法删除模块，它显示错误无法删除说“设备或资源忙。这是我的代码。

#include<linux/module.h>
#include<linux/kernel.h>
#include<linux/fs.h> /*this is the file structure, file open read close */
#include<linux/cdev.h> /* this is for character device, makes cdev avilable*/
#include<linux/semaphore.h> /* this is for the semaphore*/
#include<linux/uaccess.h> /*this is for copy_user vice vers*/
#include<linux/proc_fs.h>

#define MAX_LEN 1024
int read_info(char *page, char **start, off_t off,  int count, int *eof, void *data);
int write_info(struct file *filp, const char __user *buffer, unsigned long length, void *data);

static struct proc_dir_entry *proc_entry;
static char *info;
static int write_index;
static int read_index;

int write_info(struct file *filp, const char __user *buffer, unsigned long length, void *data) {
    int capacity = (MAX_LEN - write_index) +1;
    if(length > capacity) {
        printk(KERN_INFO "NO sapce to write into peoc file \n");
        return -1;
    }
    if(copy_from_user(&info[write_index], buffer, length)) 
        return -2;
    write_index += length;
    printk(KERN_INFO " megharaj proc writing succesful, %d write \n", length);
    return length;
}

int read_info(char *page, char **start, off_t off, int count, int *eof, void *data) {
    int len;
    len = sprintf(page, "%s\n", &info[read_index]);
    read_index += len;
    printk(KERN_INFO " megharaj proc reading succesful, %d read \n", len);
    return len;
}


int init_module(void) 
{
    int ret = 0;
    info = (char *)vmalloc(MAX_LEN);
    memset(info, 0 , MAX_LEN);
/*truct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
                                         struct proc_dir_entry *parent);*/
    proc_entry = create_proc_entry("megharaj_proc", 0666, NULL);
    if(proc_entry == NULL) {
        ret = -1;
        vfree(info);
        printk(KERN_INFO " megharaj proc not created \n");
    }
    else {
        write_index = 0;
        read_index = 0;
        proc_entry->read_proc = read_info;
        proc_entry->write_proc = write_info;
        printk(KERN_INFO " megharaj proc created \n");
    }
    return ret;
}

void clean_module(void) 
{
    vfree(info);
    remove_proc_entry("megharaj_proc", NULL);

}

还附加了makefile，

obj-m   := proc.o

KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD       := $(shell pwd)

all:
    $(MAKE) -C $(KERNELDIR) M=$(PWD)

clean:
    rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions

proc文件上的echo和cat正在运行。完成工作后，我无法使用sudo rmmod proc

删除模块

lsmod的输出显示

proc                   12518  0 [permanent]

现在另一个问题，这个永久物是什么？这是问题吗？？

Answer 1

将模块清理函数命名为cleanup_module（而不是clean_module），或者将其特别声明为清理函数（更好），如下所示：

module_init(init_module);
module_exit(clean_module);

错误：删除proc模块中的“设备或资源忙”

1 个答案: