/**

　　*  procfs2.c -  create a "file" in /proc

　　*

　　*/

#include <linux/module.h> /* Specifically, a module */
#include <linux/kernel.h> /* We're doing kernel work */
#include <linux/proc_fs.h> /* Necessary because we use the proc fs */
#include <asm/uaccess.h> /* for copy_from_user */
#define PROCFS_MAX_SIZE  1024
#define PROCFS_NAME   "buffer1k"

　　/**

　　* This structure hold information about the /proc file

　　*

　　*/

　　static struct proc_dir_entry *Our_Proc_File;

　　/**

　　* The buffer used to store character for this module

　　*

　　*/

　　static char procfs_buffer[PROCFS_MAX_SIZE];

　　/**

　　* The size of the buffer

　　*

　　*/

　　static unsigned long procfs_buffer_size = 0;

　　/**

　　* This function is called then the /proc file is read

　　*

　　*/

　　int

　　procfile_read(char *buffer,

　　char **buffer_location,

　　off_t offset, int buffer_length, int *eof, void *data)

　　{

　　int ret;

　　printk(KERN_INFO "procfile_read (/proc/%s) calledn", PROCFS_NAME);

　　if (offset > 0) {

　　/* we have finished to read, return 0 */

　　ret  = 0;

　　} else {

　　/* fill the buffer, return the buffer size */

　　memcpy(buffer, procfs_buffer, procfs_buffer_size);

　　ret = procfs_buffer_size;

　　}

　　return ret;

　　}

　　/**

　　* This function is called with the /proc file is written

　　*

　　*/

　　int procfile_write(struct file *file, const char *buffer, unsigned long count,

　　void *data)

　　{

　　/* get buffer size */

　　procfs_buffer_size = count;

　　if (procfs_buffer_size > PROCFS_MAX_SIZE ) {

　　procfs_buffer_size = PROCFS_MAX_SIZE;

　　}

　　/* write data to the buffer */

　　if ( copy_from_user(procfs_buffer, buffer, procfs_buffer_size) ) {

　　return -EFAULT;

　　}

　　return procfs_buffer_size;

　　}

　　/**

　　*This function is called when the module is loaded

　　*

　　*/

　　int init_module()

　　{

　　/* create the /proc file */

　　Our_Proc_File = create_proc_entry(PROCFS_NAME, 0644, NULL);

　　if (Our_Proc_File == NULL) {

　　remove_proc_entry(PROCFS_NAME, &proc_root);

　　printk(KERN_ALERT "Error: Could not initialize /proc/%sn",

　　PROCFS_NAME);

　　return -ENOMEM;

　　}

　　Our_Proc_File->read_proc  = procfile_read;

　　Our_Proc_File->write_proc = procfile_write;

　　Our_Proc_File->owner    = THIS_MODULE;

　　Our_Proc_File->mode    = S_IFREG | S_IRUGO;

　　Our_Proc_File->uid    = 0;

　　Our_Proc_File->gid    = 0;

　　Our_Proc_File->size    = 37;

　　printk(KERN_INFO "/proc/%s createdn", PROCFS_NAME);

　　return 0; /* everything is ok */

　　}

　　/**

　　*This function is called when the module is unloaded

　　*

　　*/

void cleanup_module()
{
    remove_proc_entry(PROCFS_NAME, &proc_root);

　　printk(KERN_INFO "/proc/%s removedn", PROCFS_NAME);

　　}