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