fs/ioctl.c

   1 /*
   2  *  linux/fs/ioctl.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include <linux/config.h>
   8 #include <linux/syscalls.h>
   9 #include <linux/mm.h>
  10 #include <linux/smp_lock.h>
  11 #include <linux/file.h>
  12 #include <linux/fs.h>
  13 #include <linux/security.h>
  14 #include <linux/module.h>
  15
  16 #include <asm/uaccess.h>
  17 #include <asm/ioctls.h>
  18
  19 static long do_ioctl(struct file *filp, unsigned int cmd,
  20                 unsigned long arg)
  21 {
  22         int error = -ENOTTY;
  23
  24         if (!filp->f_op)
  25                 goto out;
  26
  27         if (filp->f_op->unlocked_ioctl) {
  28                 error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
  29                 if (error == -ENOIOCTLCMD)
  30                         error = -EINVAL;
  31                 goto out;
  32         } else if (filp->f_op->ioctl) {
  33                 lock_kernel();
  34                 error = filp->f_op->ioctl(filp->f_dentry->d_inode,
  35                                           filp, cmd, arg);
  36                 unlock_kernel();
  37         }
  38
  39  out:
  40         return error;
  41 }
  42
  43 static int file_ioctl(struct file *filp, unsigned int cmd,
  44                 unsigned long arg)
  45 {
  46         int error;
  47         int block;
  48         struct inode * inode = filp->f_dentry->d_inode;
  49         int __user *p = (int __user *)arg;
  50
  51         switch (cmd) {
  52                 case FIBMAP:
  53                 {
  54                         struct address_space *mapping = filp->f_mapping;
  55                         int res;
  56                         /* do we support this mess? */
  57                         if (!mapping->a_ops->bmap)
  58                                 return -EINVAL;
  59                         if (!capable(CAP_SYS_RAWIO))
  60                                 return -EPERM;
  61                         if ((error = get_user(block, p)) != 0)
  62                                 return error;
  63
  64                         lock_kernel();
  65                         res = mapping->a_ops->bmap(mapping, block);
  66                         unlock_kernel();
  67                         return put_user(res, p);
  68                 }
  69                 case FIGETBSZ:
  70                         if (inode->i_sb == NULL)
  71                                 return -EBADF;
  72                         return put_user(inode->i_sb->s_blocksize, p);
  73                 case FIONREAD:
  74                         return put_user(i_size_read(inode) - filp->f_pos, p);
  75         }
  76
  77         return do_ioctl(filp, cmd, arg);
  78 }
  79
  80
  81 asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
  82 {
  83         struct file * filp;
  84         unsigned int flag;
  85         int on, error = -EBADF;
  86         int fput_needed;
  87
  88         filp = fget_light(fd, &fput_needed);
  89         if (!filp)
  90                 goto out;
  91
  92         error = security_file_ioctl(filp, cmd, arg);
  93         if (error)
  94                 goto out_fput;
  95
  96         switch (cmd) {
  97                 case FIOCLEX:
  98                         set_close_on_exec(fd, 1);
  99                         break;
 100
 101                 case FIONCLEX:
 102                         set_close_on_exec(fd, 0);
 103                         break;
 104
 105                 case FIONBIO:
 106                         if ((error = get_user(on, (int __user *)arg)) != 0)
 107                                 break;
 108                         flag = O_NONBLOCK;
 109 #ifdef __sparc__
 110                         /* SunOS compatibility item. */
 111                         if(O_NONBLOCK != O_NDELAY)
 112                                 flag |= O_NDELAY;
 113 #endif
 114                         if (on)
 115                                 filp->f_flags |= flag;
 116                         else
 117                                 filp->f_flags &= ~flag;
 118                         break;
 119
 120                 case FIOASYNC:
 121                         if ((error = get_user(on, (int __user *)arg)) != 0)
 122                                 break;
 123                         flag = on ? FASYNC : 0;
 124
 125                         /* Did FASYNC state change ? */
 126                         if ((flag ^ filp->f_flags) & FASYNC) {
 127                                 if (filp->f_op && filp->f_op->fasync) {
 128                                         lock_kernel();
 129                                         error = filp->f_op->fasync(fd, filp, on);
 130                                         unlock_kernel();
 131                                 }
 132                                 else error = -ENOTTY;
 133                         }
 134                         if (error != 0)
 135                                 break;
 136
 137                         if (on)
 138                                 filp->f_flags |= FASYNC;
 139                         else
 140                                 filp->f_flags &= ~FASYNC;
 141                         break;
 142
 143                 case FIOQSIZE:
 144                         if (S_ISDIR(filp->f_dentry->d_inode->i_mode) ||
 145                             S_ISREG(filp->f_dentry->d_inode->i_mode) ||
 146                             S_ISLNK(filp->f_dentry->d_inode->i_mode)) {
 147                                 loff_t res = inode_get_bytes(filp->f_dentry->d_inode);
 148                                 error = copy_to_user((loff_t __user *)arg, &res, sizeof(res)) ? -EFAULT : 0;
 149                         }
 150                         else
 151                                 error = -ENOTTY;
 152                         break;
 153                 default:
 154                         if (S_ISREG(filp->f_dentry->d_inode->i_mode))
 155                                 error = file_ioctl(filp, cmd, arg);
 156                         else
 157                                 error = do_ioctl(filp, cmd, arg);
 158                         break;
 159         }
 160  out_fput:
 161         fput_light(filp, fput_needed);
 162  out:
 163         return error;
 164 }
 165
 166 /*
 167  * Platforms implementing 32 bit compatibility ioctl handlers in
 168  * modules need this exported
 169  */
 170 #ifdef CONFIG_COMPAT
 171 EXPORT_SYMBOL(sys_ioctl);
 172 #endif