144 lines
2.9 KiB
C
144 lines
2.9 KiB
C
#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/debugfs.h>
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#include <linux/uaccess.h>
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#include <linux/rwlock_types.h>
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#define STUDENT_LOGIN "cchauvet"
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MODULE_LICENSE("GPL");
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struct dentry *subdir;
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struct dentry *id_file;
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struct dentry *jiffies_file;
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struct dentry *foo_file;
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static ssize_t id_read(struct file *, char *, size_t, loff_t *);
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static ssize_t id_write(struct file *, const char *, size_t, loff_t *);
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const struct file_operations id_file_fops = {
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.owner = THIS_MODULE,
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.write = id_write,
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.read = id_read,
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};
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static ssize_t foo_read(struct file *, char *, size_t, loff_t *);
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static ssize_t foo_write(struct file *, const char *, size_t, loff_t *);
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const struct file_operations foo_file_fops = {
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.owner = THIS_MODULE,
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.write = foo_write,
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.read = foo_read,
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};
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char foo_data[PAGE_SIZE];
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size_t foo_data_len = 0;
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DEFINE_MUTEX(foo_data_mutex);
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static int __init module_start(void)
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{
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subdir = debugfs_create_dir("fortytwo", NULL);
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if (!subdir)
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goto create_fail;
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id_file = debugfs_create_file("id", 0666, subdir, NULL, &id_file_fops);
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if (!id_file)
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goto create_fail;
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debugfs_create_size_t("jiffies", 0444, subdir, (size_t *) &jiffies);
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foo_file = debugfs_create_file("foo",0644, subdir, NULL, &foo_file_fops);
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if (!foo_file)
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goto create_fail;
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printk(KERN_INFO "Hello world !\n");
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return 0;
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create_fail:
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debugfs_remove_recursive(subdir);
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return -ENOENT;
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}
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static void __exit module_end(void)
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{
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debugfs_remove_recursive(subdir);
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printk(KERN_INFO "Cleaning up module.\n");
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}
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static ssize_t id_read(struct file *f, char *buf, size_t len, loff_t *f_pos)
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{
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char data[] = STUDENT_LOGIN;
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size_t data_len = strlen(data);
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if(*f_pos > 0)
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return 0;
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if (copy_to_user(buf, data, data_len))
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return -EFAULT;
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*f_pos += data_len;
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return data_len;
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}
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static ssize_t id_write(struct file *f, const char *buf, size_t len, loff_t *offset)
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{
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char data[10];
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size_t len_red = 10 > len ? len : 10;
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if (copy_from_user(data, buf, len_red))
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return -EFAULT;
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if (strcmp(data, STUDENT_LOGIN))
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return -EINVAL;
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return len_red;
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}
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static ssize_t foo_read(struct file *f, char __user *buf, size_t len, loff_t *offset)
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{
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size_t len_red;
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mutex_lock(&foo_data_mutex);
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if (!buf)
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return -EINVAL;
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if (*offset > foo_data_len)
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return 0;
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if (len + *offset >= foo_data_len)
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len_red = foo_data_len - *offset;
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else
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len_red = len;
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if (copy_to_user(buf, foo_data + *offset, len_red))
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return -EFAULT;
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mutex_unlock(&foo_data_mutex);
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*offset += len_red;
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return len_red;
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}
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static ssize_t foo_write(struct file *, const char __user *buf, size_t len, loff_t *offset)
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{
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if (len > PAGE_SIZE)
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return -EINVAL;
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mutex_lock(&foo_data_mutex);
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if (copy_from_user(foo_data, buf, len))
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return -EFAULT;
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foo_data_len = len;
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mutex_unlock(&foo_data_mutex);
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*offset = len;
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return len;
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}
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module_init(module_start);
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module_exit(module_end);
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