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                         return put_user(inode->i_sb->s_blocksize, p);
  71                 case FIONREAD:
  72                         return put_user(i_size_read(inode) - filp->f_pos, p);
  73         }
  74
  75         return do_ioctl(filp, cmd, arg);
  76 }
  77
  78 /*
  79  * When you add any new common ioctls to the switches above and below
  80  * please update compat_sys_ioctl() too.
  81  *
  82  * vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
  83  * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
  84  */
  85 int vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, unsigned long arg)
  86 {
  87         unsigned int flag;
  88         int on, error = 0;
  89
  90         switch (cmd) {
  91                 case FIOCLEX:
  92                         set_close_on_exec(fd, 1);
  93                         break;
  94
  95                 case FIONCLEX:
  96                         set_close_on_exec(fd, 0);
  97                         break;
  98
  99                 case FIONBIO:
 100                         if ((error = get_user(on, (int __user *)arg)) != 0)
 101                                 break;
 102                         flag = O_NONBLOCK;
 103 #ifdef __sparc__
 104                         /* SunOS compatibility item. */
 105                         if(O_NONBLOCK != O_NDELAY)
 106                                 flag |= O_NDELAY;
 107 #endif
 108                         if (on)
 109                                 filp->f_flags |= flag;
 110                         else
 111                                 filp->f_flags &= ~flag;
 112                         break;
 113
 114                 case FIOASYNC:
 115                         if ((error = get_user(on, (int __user *)arg)) != 0)
 116                                 break;
 117                         flag = on ? FASYNC : 0;
 118
 119                         /* Did FASYNC state change ? */
 120                         if ((flag ^ filp->f_flags) & FASYNC) {
 121                                 if (filp->f_op && filp->f_op->fasync) {
 122                                         lock_kernel();
 123                                         error = filp->f_op->fasync(fd, filp, on);
 124                                         unlock_kernel();
 125                                 }
 126                                 else error = -ENOTTY;
 127                         }
 128                         if (error != 0)
 129                                 break;
 130
 131                         if (on)
 132                                 filp->f_flags |= FASYNC;
 133                         else
 134                                 filp->f_flags &= ~FASYNC;
 135                         break;
 136
 137                 case FIOQSIZE:
 138                         if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) ||
 139                             S_ISREG(filp->f_path.dentry->d_inode->i_mode) ||
 140                             S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) {
 141                                 loff_t res = inode_get_bytes(filp->f_path.dentry->d_inode);
 142                                 error = copy_to_user((loff_t __user *)arg, &res, sizeof(res)) ? -EFAULT : 0;
 143                         }
 144                         else
 145                                 error = -ENOTTY;
 146                         break;
 147                 default:
 148                         if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
 149                                 error = file_ioctl(filp, cmd, arg);
 150                         else
 151                                 error = do_ioctl(filp, cmd, arg);
 152                         break;
 153         }
 154         return error;
 155 }
 156
 157 asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
 158 {
 159         struct file * filp;
 160         int error = -EBADF;
 161         int fput_needed;
 162
 163         filp = fget_light(fd, &fput_needed);
 164         if (!filp)
 165                 goto out;
 166
 167         error = security_file_ioctl(filp, cmd, arg);
 168         if (error)
 169                 goto out_fput;
 170
 171         error = vfs_ioctl(filp, fd, cmd, arg);
 172  out_fput:
 173         fput_light(filp, fput_needed);
 174  out:
 175         return error;
 176 }
 177
 178 /*
 179  * Platforms implementing 32 bit compatibility ioctl handlers in
 180  * modules need this exported
 181  */
 182 #ifdef CONFIG_COMPAT
 183 EXPORT_SYMBOL(sys_ioctl);
 184 #endif