mirror of
https://github.com/sysprog21/lkmpg.git
synced 2024-11-22 15:05:54 +08:00
100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
/*
|
|
* procfs2.c - create a "file" in /proc
|
|
*/
|
|
|
|
#include <linux/kernel.h> /* We're doing kernel work */
|
|
#include <linux/module.h> /* Specifically, a module */
|
|
#include <linux/proc_fs.h> /* Necessary because we use the proc fs */
|
|
#include <linux/uaccess.h> /* for copy_from_user */
|
|
#include <linux/version.h>
|
|
|
|
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
|
|
#define HAVE_PROC_OPS
|
|
#endif
|
|
|
|
#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 */
|
|
ssize_t procfile_read(struct file *filePointer,
|
|
char *buffer,
|
|
size_t buffer_length,
|
|
loff_t *offset)
|
|
{
|
|
char s[13] = "HelloWorld!\n";
|
|
int len = sizeof(s);
|
|
ssize_t ret = len;
|
|
|
|
if (*offset >= len || copy_to_user(buffer, s, len)) {
|
|
pr_info("copy_to_user failed\n");
|
|
ret = 0;
|
|
} else {
|
|
pr_info("procfile read %s\n", filePointer->f_path.dentry->d_name.name);
|
|
*offset += len;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* This function is called with the /proc file is written. */
|
|
static ssize_t procfile_write(struct file *file,
|
|
const char *buff,
|
|
size_t len,
|
|
loff_t *off)
|
|
{
|
|
procfs_buffer_size = len;
|
|
if (procfs_buffer_size > PROCFS_MAX_SIZE)
|
|
procfs_buffer_size = PROCFS_MAX_SIZE;
|
|
|
|
if (copy_from_user(procfs_buffer, buff, procfs_buffer_size))
|
|
return -EFAULT;
|
|
|
|
procfs_buffer[procfs_buffer_size] = '\0';
|
|
return procfs_buffer_size;
|
|
}
|
|
|
|
#ifdef HAVE_PROC_OPS
|
|
static const struct proc_ops proc_file_fops = {
|
|
.proc_read = procfile_read,
|
|
.proc_write = procfile_write,
|
|
};
|
|
#else
|
|
static const struct file_operations proc_file_fops = {
|
|
.read = procfile_read,
|
|
.write = procfile_write,
|
|
};
|
|
#endif
|
|
|
|
static int __init procfs2_init(void)
|
|
{
|
|
Our_Proc_File = proc_create(PROCFS_NAME, 0644, NULL, &proc_file_fops);
|
|
if (NULL == Our_Proc_File) {
|
|
proc_remove(Our_Proc_File);
|
|
pr_alert("Error:Could not initialize /proc/%s\n", PROCFS_NAME);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
pr_info("/proc/%s created\n", PROCFS_NAME);
|
|
return 0;
|
|
}
|
|
|
|
static void __exit procfs2_exit(void)
|
|
{
|
|
proc_remove(Our_Proc_File);
|
|
pr_info("/proc/%s removed\n", PROCFS_NAME);
|
|
}
|
|
|
|
module_init(procfs2_init);
|
|
module_exit(procfs2_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|