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/capability.h>
  12 #include <linux/file.h>
  13 #include <linux/fs.h>
  14 #include <linux/security.h>
  15 #include <linux/module.h>
  16
  17 #include <asm/uaccess.h>
  18 #include <asm/ioctls.h>
  19
  20 static long do_ioctl(struct file *filp, unsigned int cmd,
  21                 unsigned long arg)
  22 {
  23         int error = -ENOTTY;
  24
  25         if (!filp->f_op)
  26                 goto out;
  27
  28         if (filp->f_op->unlocked_ioctl) {
  29                 error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
  30                 if (error == -ENOIOCTLCMD)
  31                         error = -EINVAL;
  32                 goto out;
  33         } else if (filp->f_op->ioctl) {
  34                 lock_kernel();
  35                 error = filp->f_op->ioctl(filp->f_dentry->d_inode,
  36                                           filp, cmd, arg);
  37                 unlock_kernel();
  38         }
  39
  40  out:
  41         return error;
  42 }
  43
  44 static int file_ioctl(struct file *filp, unsigned int cmd,
  45                 unsigned long arg)
  46 {
  47         int error;
  48         int block;
  49         struct inode * inode = filp->f_dentry->d_inode;
  50         int __user *p = (int __user *)arg;
  51
  52         switch (cmd) {
  53                 case FIBMAP:
  54                 {
  55                         struct address_space *mapping = filp->f_mapping;
  56                         int res;
  57                         /* do we support this mess? */
  58                         if (!mapping->a_ops->bmap)
  59                                 return -EINVAL;
  60                         if (!capable(CAP_SYS_RAWIO))
  61                                 return -EPERM;
  62                         if ((error = get_user(block, p)) != 0)
  63                                 return error;
  64
  65                         lock_kernel();
  66                         res = mapping->a_ops->bmap(mapping, block);
  67                         unlock_kernel();
  68                         return put_user(res, p);
  69                 }
  70                 case FIGETBSZ:
  71                         if (inode->i_sb == NULL)
  72                                 return -EBADF;
  73                         return put_user(inode->i_sb->s_blocksize, p);
  74                 case FIONREAD:
  75                         return put_user(i_size_read(inode) - filp->f_pos, p);
  76         }
  77
  78         return do_ioctl(filp, cmd, arg);
  79 }
  80
  81 /*
  82  * When you add any new common ioctls to the switches above and below
  83  * please update compat_sys_ioctl() too.
  84  *
  85  * vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
  86  * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
  87  */
  88 int vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, unsigned long arg)
  89 {
  90         unsigned int flag;
  91         int on, error = 0;
  92
  93         switch (cmd) {
  94                 case FIOCLEX:
  95                         set_close_on_exec(fd, 1);
  96                         break;
  97
  98                 case FIONCLEX:
  99                         set_close_on_exec(fd, 0);
 100                         break;
 101
 102                 case FIONBIO:
 103                         if ((error = get_user(on, (int __user *)arg)) != 0)
 104                                 break;
 105                         flag = O_NONBLOCK;
 106 #ifdef __sparc__
 107                         /* SunOS compatibility item. */
 108                         if(O_NONBLOCK != O_NDELAY)
 109                                 flag |= O_NDELAY;
 110 #endif
 111                         if (on)
 112                                 filp->f_flags |= flag;
 113                         else
 114                                 filp->f_flags &= ~flag;
 115                         break;
 116
 117                 case FIOASYNC:
 118                         if ((error = get_user(on, (int __user *)arg)) != 0)
 119                                 break;
 120                         flag = on ? FASYNC : 0;
 121
 122                         /* Did FASYNC state change ? */
 123                         if ((flag ^ filp->f_flags) & FASYNC) {
 124                                 if (filp->f_op && filp->f_op->fasync) {
 125                                         lock_kernel();
 126                                         error = filp->f_op->fasync(fd, filp, on);
 127                                         unlock_kernel();
 128                                 }
 129                                 else error = -ENOTTY;
 130                         }
 131                         if (error != 0)
 132                                 break;
 133
 134                         if (on)
 135                                 filp->f_flags |= FASYNC;
 136                         else
 137                                 filp->f_flags &= ~FASYNC;
 138                         break;
 139
 140                 case FIOQSIZE:
 141                         if (S_ISDIR(filp->f_dentry->d_inode->i_mode) ||
 142                             S_ISREG(filp->f_dentry->d_inode->i_mode) ||
 143                             S_ISLNK(filp->f_dentry->d_inode->i_mode)) {
 144                                 loff_t res = inode_get_bytes(filp->f_dentry->d_inode);
 145                                 error = copy_to_user((loff_t __user *)arg, &res, sizeof(res)) ? -EFAULT : 0;
 146                         }
 147                         else
 148                                 error = -ENOTTY;
 149                         break;
 150                 default:
 151                         if (S_ISREG(filp->f_dentry->d_inode->i_mode))
 152                                 error = file_ioctl(filp, cmd, arg);
 153                         else
 154                                 error = do_ioctl(filp, cmd, arg);
 155                         break;
 156         }
 157         return error;
 158 }
 159
 160 asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
 161 {
 162         struct file * filp;
 163         int error = -EBADF;
 164         int fput_needed;
 165
 166         filp = fget_light(fd, &fput_needed);
 167         if (!filp)
 168                 goto out;
 169
 170         error = security_file_ioctl(filp, cmd, arg);
 171         if (error)
 172                 goto out_fput;
 173
 174         error = vfs_ioctl(filp, fd, cmd, arg);
 175  out_fput:
 176         fput_light(filp, fput_needed);
 177  out:
 178         return error;
 179 }
 180
 181 /*
 182  * Platforms implementing 32 bit compatibility ioctl handlers in
 183  * modules need this exported
 184  */
 185 #ifdef CONFIG_COMPAT
 186 EXPORT_SYMBOL(sys_ioctl);
 187 #endif