fs/ioctl.c

   1 /*
   2  *  linux/fs/ioctl.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include <linux/syscalls.h>
   8 #include <linux/mm.h>
   9 #include <linux/smp_lock.h>
  10 #include <linux/capability.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_path.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_path.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  * When you add any new common ioctls to the switches above and below
  82  * please update compat_sys_ioctl() too.
  83  *
  84  * vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
  85  * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
  86  */
  87 int vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, unsigned long arg)
  88 {
  89         unsigned int flag;
  90         int on, error = 0;
  91
  92         switch (cmd) {
  93                 case FIOCLEX:
  94                         set_close_on_exec(fd, 1);
  95                         break;
  96
  97                 case FIONCLEX:
  98                         set_close_on_exec(fd, 0);
  99                         break;
 100
 101                 case FIONBIO:
 102                         if ((error = get_user(on, (int __user *)arg)) != 0)
 103                                 break;
 104                         flag = O_NONBLOCK;
 105 #ifdef __sparc__
 106                         /* SunOS compatibility item. */
 107                         if(O_NONBLOCK != O_NDELAY)
 108                                 flag |= O_NDELAY;
 109 #endif
 110                         if (on)
 111                                 filp->f_flags |= flag;
 112                         else
 113                                 filp->f_flags &= ~flag;
 114                         break;
 115
 116                 case FIOASYNC:
 117                         if ((error = get_user(on, (int __user *)arg)) != 0)
 118                                 break;
 119                         flag = on ? FASYNC : 0;
 120
 121                         /* Did FASYNC state change ? */
 122                         if ((flag ^ filp->f_flags) & FASYNC) {
 123                                 if (filp->f_op && filp->f_op->fasync) {
 124                                         lock_kernel();
 125                                         error = filp->f_op->fasync(fd, filp, on);
 126                                         unlock_kernel();
 127                                 }
 128                                 else error = -ENOTTY;
 129                         }
 130                         if (error != 0)
 131                                 break;
 132
 133                         if (on)
 134                                 filp->f_flags |= FASYNC;
 135                         else
 136                                 filp->f_flags &= ~FASYNC;
 137                         break;
 138
 139                 case FIOQSIZE:
 140                         if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) ||
 141                             S_ISREG(filp->f_path.dentry->d_inode->i_mode) ||
 142                             S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) {
 143                                 loff_t res = inode_get_bytes(filp->f_path.dentry->d_inode);
 144                                 error = copy_to_user((loff_t __user *)arg, &res, sizeof(res)) ? -EFAULT : 0;
 145                         }
 146                         else
 147                                 error = -ENOTTY;
 148                         break;
 149                 default:
 150                         if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
 151                                 error = file_ioctl(filp, cmd, arg);
 152                         else
 153                                 error = do_ioctl(filp, cmd, arg);
 154                         break;
 155         }
 156         return error;
 157 }
 158
 159 asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
 160 {
 161         struct file * filp;
 162         int error = -EBADF;
 163         int fput_needed;
 164
 165         filp = fget_light(fd, &fput_needed);
 166         if (!filp)
 167                 goto out;
 168
 169         error = security_file_ioctl(filp, cmd, arg);
 170         if (error)
 171                 goto out_fput;
 172
 173         error = vfs_ioctl(filp, fd, cmd, arg);
 174  out_fput:
 175         fput_light(filp, fput_needed);
 176  out:
 177         return error;
 178 }
 179
 180 /*
 181  * Platforms implementing 32 bit compatibility ioctl handlers in
 182  * modules need this exported
 183  */
 184 #ifdef CONFIG_COMPAT
 185 EXPORT_SYMBOL(sys_ioctl);
 186 #endif