#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <asm/uaccess.h>
#include <linux/sched.h>
static int itype=0;
module_param(itype, int, 0);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("PROC FILE DEMO");
#define MAX_LENGTH 500
#define MAX_proc_LENGTH 1024
static struct proc_dir_entry *proc_entry;
static char *proc_buffer;
int proc_read( char *page, char **start, off_t off,int count, int *eof, void *data )
{
int size = 0;
struct task_struct *p;
char state;
size+=sprintf(page+size, "%5s%7s%7s%7s%7s%7s%7s %s\n\n", "PID","UID","PRIO","POLICY", "STATE","UTIME","STIME","COMMAND");
for_each_process(p)
{
switch((int)p->state)
{
case -1: state='Z'; break;
case 0: state='R'; break;
default: state='S'; break;
}
size+=sprintf(page+size,
"%5d%7d%7d%7d%7c%7d%7d %s\n",
(int)p->pid,
(int)p->uid,
(int)p->rt_priority,
(int)p->policy,
state,
(int)p->utime,
(int)p->stime,
p->comm);
}
return (size);
}
ssize_t proc_write( struct file *filp, const char __user *buff, unsigned long len, void *data )
{
if(len>MAX_LENGTH)len=MAX_LENGTH;
if (copy_from_user(proc_buffer, buff, len ))
{
return -EFAULT;
}
proc_buffer[len] = 0;
printk(KERN_INFO "proc_write: %s\n",proc_buffer);
return len;
}
// 函数返回0允许操作、返回非0不允许操作并指出不允许操作的原因
static int proc_permission(struct inode *inode, int op, struct nameidata *foo)
{
printk(KERN_INFO "proc_permission op %d\n",op);
if(itype==op)
{
return -EACCES;
}
return 0;
}
static struct inode_operations proc_inode_operations = {
.permission = proc_permission,
};
int init_proc_module( void )
{
int ret = 0;
proc_buffer = (char *)vmalloc( MAX_proc_LENGTH );
if (!proc_buffer)
{
ret = -ENOMEM;
}
else
{
memset( proc_buffer, 0, MAX_LENGTH );
proc_entry = create_proc_entry( "demo", 0644, NULL );
if (proc_entry == NULL)
{
ret = -ENOMEM;
vfree(proc_buffer);
printk(KERN_INFO "demo: Couldn't create proc entry\n");
}
else
{
proc_entry->proc_iops = &proc_inode_operations;
proc_entry->read_proc = proc_read;
proc_entry->write_proc = proc_write;
proc_entry->owner = THIS_MODULE;
printk(KERN_INFO "demo: Module loaded.\n");
}
}
return ret;
}
void cleanup_proc_module( void )
{
remove_proc_entry("demo", &proc_entry);
vfree(proc_buffer);
printk(KERN_INFO "demo: Module unloaded.\n");
}
module_init( init_proc_module );
module_exit( cleanup_proc_module );
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