copy_to_user -- Copy a block of data into user space.
copy_from_user -- Copy a block of data from user space.
get_user -- Get a simple variable from user space.
put_user -- Write a simple value into user space.
copy_from_user -- Copy a block of data from user space.
get_user -- Get a simple variable from user space.
put_user -- Write a simple value into user space.
copy_from_user
Arguments
- to
-
Destination address, in kernel space.
- from
-
Source address, in user space.
- n
-
Number of bytes to copy.
Description
Copy data from user space to kernel space.
Returns number of bytes that could not be copied. On success, this will be zero.
If some data could not be copied, this function will pad the copied data to the requested size using zero bytes.
copy_to_user
Arguments
- to
-
Destination address, in user space.
- from
-
Source address, in kernel space.
- n
-
Number of bytes to copy.
Description
Copy data from kernel space to user space.
Returns number of bytes that could not be copied. On success, this will be zero.
put_user
Description
This macro copies a single simple value from kernel space to user space. It supports simple types like char and int, but not larger data types like structures or arrays.
ptr must have pointer-to-simple-variable type, and x must be assignable to the result of dereferencing ptr.
Returns zero on success, or -EFAULT on error.
get_user
Description
This macro copies a single simple variable from user space to kernel space. It supports simple types like char and int, but not larger data types like structures or arrays.
ptr must have pointer-to-simple-variable type, and the result of dereferencing ptr must be assignable to x without a cast.
Returns zero on success, or -EFAULT on error. On error, the variable x is set to zero.