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 #include <linux/kallsyms.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         void *f;
  25
  26         if (!filp->f_op)
  27                 goto out;
  28
  29         if (filp->f_op->unlocked_ioctl) {
  30                 error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
  31                 if (error == -ENOIOCTLCMD)
  32                         error = -EINVAL;
  33                 goto out;
  34         } else if ((f = filp->f_op->ioctl)) {
  35                 lock_kernel();
  36                 if (!filp->f_op->ioctl) {
  37                         printk("%s: ioctl %p disappeared\n", __FUNCTION__, f);
  38                         print_symbol("symbol: %s\n", (unsigned long)f);
  39                         dump_stack();
  40                 } else {
  41                         error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,
  42                                                   filp, cmd, arg);
  43                 }
  44                 unlock_kernel();
  45         }
  46
  47  out:
  48         return error;
  49 }
  50
  51 static int file_ioctl(struct file *filp, unsigned int cmd,
  52                 unsigned long arg)
  53 {
  54         int error;
  55         int block;
  56         struct inode * inode = filp->f_path.dentry->d_inode;
  57         int __user *p = (int __user *)arg;
  58
  59         switch (cmd) {
  60                 case FIBMAP:
  61                 {
  62                         struct address_space *mapping = filp->f_mapping;
  63                         int res;
  64                         /* do we support this mess? */
  65                         if (!mapping->a_ops->bmap)
  66                                 return -EINVAL;
  67                         if (!capable(CAP_SYS_RAWIO))
  68                                 return -EPERM;
  69                         if ((error = get_user(block, p)) != 0)
  70                                 return error;
  71
  72                         lock_kernel();
  73                         res = mapping->a_ops->bmap(mapping, block);
  74                         unlock_kernel();
  75                         return put_user(res, p);
  76                 }
  77                 case FIGETBSZ:
  78                         return put_user(inode->i_sb->s_blocksize, p);
  79                 case FIONREAD:
  80                         return put_user(i_size_read(inode) - filp->f_pos, p);
  81         }
  82
  83         return do_ioctl(filp, cmd, arg);
  84 }
  85
  86 /*
  87  * When you add any new common ioctls to the switches above and below
  88  * please update compat_sys_ioctl() too.
  89  *
  90  * vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
  91  * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
  92  */
  93 int vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, unsigned long arg)
  94 {
  95         unsigned int flag;
  96         int on, error = 0;
  97
  98         switch (cmd) {
  99                 case FIOCLEX:
 100                         set_close_on_exec(fd, 1);
 101                         break;
 102
 103                 case FIONCLEX:
 104                         set_close_on_exec(fd, 0);
 105                         break;
 106
 107                 case FIONBIO:
 108                         if ((error = get_user(on, (int __user *)arg)) != 0)
 109                                 break;
 110                         flag = O_NONBLOCK;
 111 #ifdef __sparc__
 112                         /* SunOS compatibility item. */
 113                         if(O_NONBLOCK != O_NDELAY)
 114                                 flag |= O_NDELAY;
 115 #endif
 116                         if (on)
 117                                 filp->f_flags |= flag;
 118                         else
 119                                 filp->f_flags &= ~flag;
 120                         break;
 121
 122                 case FIOASYNC:
 123                         if ((error = get_user(on, (int __user *)arg)) != 0)
 124                                 break;
 125                         flag = on ? FASYNC : 0;
 126
 127                         /* Did FASYNC state change ? */
 128                         if ((flag ^ filp->f_flags) & FASYNC) {
 129                                 if (filp->f_op && filp->f_op->fasync) {
 130                                         lock_kernel();
 131                                         error = filp->f_op->fasync(fd, filp, on);
 132                                         unlock_kernel();
 133                                 }
 134                                 else error = -ENOTTY;
 135                         }
 136                         if (error != 0)
 137                                 break;
 138
 139                         if (on)
 140                                 filp->f_flags |= FASYNC;
 141                         else
 142                                 filp->f_flags &= ~FASYNC;
 143                         break;
 144
 145                 case FIOQSIZE:
 146                         if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) ||
 147                             S_ISREG(filp->f_path.dentry->d_inode->i_mode) ||
 148                             S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) {
 149                                 loff_t res = inode_get_bytes(filp->f_path.dentry->d_inode);
 150                                 error = copy_to_user((loff_t __user *)arg, &res, sizeof(res)) ? -EFAULT : 0;
 151                         }
 152                         else
 153                                 error = -ENOTTY;
 154                         break;
 155                 default:
 156                         if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
 157                                 error = file_ioctl(filp, cmd, arg);
 158                         else
 159                                 error = do_ioctl(filp, cmd, arg);
 160                         break;
 161         }
 162         return error;
 163 }
 164
 165 asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
 166 {
 167         struct file * filp;
 168         int error = -EBADF;
 169         int fput_needed;
 170
 171         filp = fget_light(fd, &fput_needed);
 172         if (!filp)
 173                 goto out;
 174
 175         error = security_file_ioctl(filp, cmd, arg);
 176         if (error)
 177                 goto out_fput;
 178
 179         error = vfs_ioctl(filp, fd, cmd, arg);
 180  out_fput:
 181         fput_light(filp, fput_needed);
 182  out:
 183         return error;
 184 }
 185
 186 /*
 187  * Platforms implementing 32 bit compatibility ioctl handlers in
 188  * modules need this exported
 189  */
 190 #ifdef CONFIG_COMPAT
 191 EXPORT_SYMBOL(sys_ioctl);
 192 #endif