ecio-proxy/ecio-proxy.c

   1
   2 /*
   3  *  Ecio proxy module 2011 (c) Yury Makarevich
   4  *
   5  *  We wrap register_chrdev/unregister_chrdev, copy_from_user
   6  */
   7
   8 /*
   9  *  Kernel config:  disable SMP, disable module versioning.
  10  *
  11  *  EcIo.ko config: patch the appropriate symbols, rename per_cpu__current_task to current_task (remove?),
  12  *                  remove spin_lock related code.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/fs.h>
  18
  19 #include <asm/uaccess.h>
  20
  21 /*
  22     The following structure was copied from 2.6.22 kernel
  23  */
  24
  25 struct legacy_file_operations {
  26         struct module *owner;
  27         loff_t (*llseek) (struct file *, loff_t, int);
  28         ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
  29         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
  30         ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
  31         ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
  32         int (*readdir) (struct file *, void *, filldir_t);
  33         unsigned int (*poll) (struct file *, struct poll_table_struct *);
  34         int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
  35         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
  36         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
  37         int (*mmap) (struct file *, struct vm_area_struct *);
  38         int (*open) (struct inode *, struct file *);
  39         int (*flush) (struct file *, fl_owner_t id);
  40         int (*release) (struct inode *, struct file *);
  41         int (*fsync) (struct file *, struct dentry *, int datasync);
  42         int (*aio_fsync) (struct kiocb *, int datasync);
  43         int (*fasync) (int, struct file *, int);
  44         int (*lock) (struct file *, int, struct file_lock *);
  45         ssize_t (*sendfile) (struct file *, loff_t *, size_t, read_actor_t, void *);
  46         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
  47         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
  48         int (*check_flags)(int);
  49         int (*dir_notify)(struct file *filp, unsigned long arg);
  50         int (*flock) (struct file *, int, struct file_lock *);
  51         ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
  52         ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
  53 };
  54
  55 static long proxy_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
  56
  57 static const struct legacy_file_operations     *legacy_fops = NULL;
  58 static struct file_operations             proxy_fops = {
  59     .unlocked_ioctl     = proxy_ioctl,
  60 };
  61
  62
  63 int register_ecio(unsigned int major, const char *name,
  64                     const struct legacy_file_operations *lfops)
  65 {
  66     // wrap file_operations here
  67     legacy_fops = lfops;
  68
  69     proxy_fops.open     = legacy_fops->open;
  70     proxy_fops.read     = legacy_fops->read;
  71     proxy_fops.write    = legacy_fops->write;
  72     proxy_fops.release  = legacy_fops->release;
  73
  74     return register_chrdev(major, name, &proxy_fops);
  75 }
  76
  77 int unregister_ecio(unsigned int major, const char *name)
  78 {
  79     unregister_chrdev(major, name);
  80     return 0;
  81 }
  82
  83 /////////////////////////////////////////////////////////////////
  84
  85 static spinlock_t   proxy_ioctl_lock;
  86
  87 static long proxy_ioctl(struct file *file, unsigned int cmd, unsigned long arg) {
  88     long  result;
  89
  90     printk(KERN_INFO "ecio-proxy ioctl %d\n", cmd);
  91
  92     spin_lock(&proxy_ioctl_lock);
  93     result = legacy_fops->ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
  94     spin_unlock(&proxy_ioctl_lock);
  95
  96     return result;
  97 }
  98
  99 unsigned long copy_from_ecio(void *to, const void __user *from, unsigned long n)
 100 {
 101     return copy_from_user(to, from, n);
 102 }
 103
 104 void _spin_ecio(spinlock_t *lock) {
 105 }
 106
 107 /////////////////////////////////////////////////////////////////
 108
 109 int init_module (void) {
 110     printk(KERN_INFO "ecio-proxy inserted\n");
 111     return 0;
 112 }
 113
 114 void cleanup_module (void) {
 115     printk(KERN_INFO "ecio-proxy removed\n");
 116 }
 117
 118 EXPORT_SYMBOL(register_ecio);
 119 EXPORT_SYMBOL(unregister_ecio);
 120 EXPORT_SYMBOL(copy_from_ecio);
 121 EXPORT_SYMBOL(_spin_ecio);