linux proc fs node
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>#ifdef CONFIG_PROC_FSextern int xx_node_val;static int xx_node_proc_show(struct seq_file *m, void *v)
{seq_printf(m, "%d\n", console_klog_enable);return 0;
}static int xx_node_proc_open(struct inode *inode, struct file *file)
{return single_open(file, xx_node_proc_show, PDE_DATA(inode));
}static ssize_t xx_node_proc_write(struct file *file, const char __user *buf,size_t count, loff_t *pos)
{char lbuf[10] = {0};int val;/* if (!capable(CAP_SYS_ADMIN))return -EACCES; */if (count >= sizeof(lbuf))count = sizeof(lbuf)-1;if (copy_from_user(lbuf, buf, count))return -EFAULT;lbuf[count] = 0;sscanf(lbuf, "%d", &val);if (val == 0) {xx_node_val = 0;} else if (val == 1) {xx_node_val = 1;} else {pr_warn("%s() set val:%d, invalid argument, expect '0' or '1'\n", __func__, val);return -EINVAL; }return count;
}static const struct file_operations xx_node_proc_fops = {.owner = THIS_MODULE,.open = xx_node_proc_open,.read = seq_read,.llseek = seq_lseek,.release = single_release,.write = xx_node_proc_write,
};static int __init xx_node_create_procfs(void)
{struct proc_dir_entry *ent;ent = proc_create_data("xx_node", S_IRUGO|S_IWUSR, NULL,&xx_node_proc_fops, NULL);if (ent == NULL)return -1;return 0;
}module_init(xx_node_create_procfs)
#endif