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