proc文件系统

  1 #include <linux/module.h>
  2 #include <linux/types.h>
  3 #include <linux/kernel.h>
  4 #include <linux/init.h>
  5 #include <linux/random.h>
  6 #include <linux/slab.h>
  7 #include <linux/proc_fs.h>
  8 #include <linux/seq_file.h>
  9 #include <linux/list.h>
 10 
 11 struct mylist_random {
 12     struct list_head list;
 13     char info[50];
 14 };
 15 
 16 static LIST_HEAD(test_list);
 17 
 18 static void *seq_start(struct seq_file *m, loff_t *pos)
 19 {
 20     return seq_list_start(&test_list, *pos);;    
 21 }
 22 
 23 static void seq_stop(struct seq_file *m, void *v)
 24 {
 25     /* No cleanup needed in this example */
 26 }
 27 
 28 static void *seq_next(struct seq_file *m, void *v, loff_t *pos)
 29 {
 30     return seq_list_next(v, &test_list, pos);
 31 }
 32 
 33 static int seq_show(struct seq_file *m, void *v)
 34 {
 35     const struct mylist_random *p = list_entry(v, struct mylist_random, list);
 36     
 37     seq_printf(m, "%s", p->info);
 38         
 39     return 0;
 40 }
 41 
 42 static const struct seq_operations seq_test_ops = {
 43     .start  = seq_start,
 44     .next   = seq_next,
 45     .stop   = seq_stop,
 46     .show   = seq_show,
 47 };
 48 
 49 static int seq_test_open(struct inode *inode, struct file *file)
 50 {
 51     return seq_open(file, &seq_test_ops);
 52 }
 53 
 54 static const struct file_operations seq_test_fops = {
 55     .owner        = THIS_MODULE,
 56     .open        = seq_test_open,
 57     .read        = seq_read,
 58     .llseek        = seq_lseek,
 59     .release    = seq_release,
 60 };
 61 
 62 static int __init seq_test_init(void)
 63 {
 64     int i, count;
 65     struct mylist_random *mylist_node;
 66     struct proc_dir_entry *p;
 67 
 68     p = proc_create("seq_file_test", S_IRUGO, NULL, &seq_test_fops);
 69     if (!p)
 70     goto out;
 71 
 72     for(i = 0; i < 10; i++) {
 73     mylist_node = kmalloc(sizeof(struct mylist_random), GFP_ATOMIC);
 74     if (!mylist_node)
 75         return -ENOMEM;
 76     memset(mylist_node, 0, sizeof(struct mylist_random));
 77     get_random_bytes(&count, sizeof(int));
 78     sprintf(mylist_node->info, "random number %d: %d\n", i, count);
 79     printk("%s", mylist_node->info);
 80     list_add_tail(&mylist_node->list, &test_list);
 81     }
 82     
 83     return 0;
 84 out:
 85     remove_proc_entry("seq_file_test", NULL);
 86     return -EFAULT;
 87 }
 88 
 89 static void __exit seq_test_exit(void)
 90 {
 91     struct list_head *p, *q;
 92     struct mylist_random *mylist_node;
 93 
 94     list_for_each_safe(p, q, &test_list) {
 95     mylist_node = list_entry(p, struct mylist_random, list);
 96     list_del(p);
 97     kfree(mylist_node);
 98     }
 99 
100     remove_proc_entry("seq_file_test", NULL);
101 }
102 
103 module_init(seq_test_init);
104 module_exit(seq_test_exit);
105 
106 MODULE_AUTHOR("Richard Tang <tanglinux@gmail.com>");
107 MODULE_LICENSE("GPL");