linux kernel proc文件系统
在linux内核模块开发中如果需要用到文件IO，使用proc文件系统是一个很好的方法。
给大家转一个例子供参考
/**
* 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) called\n", 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/%s\n",
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 created\n", 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 removed\n", PROCFS_NAME);
}
关键词标签：linux
