put_user_byte()

put_user_byte()

[blesson paul]

Hi all
                I need to copy some data from kernel memory space to user 
memory space. When I investigated, the command for that purpose is 
put_user_byte(). But in kernel2.4, I can't find the implementation of this 
command. I want to know the command which replaced put_user_byte() in 2.4 
kernel. Also I want to know whether there is any synonyms for verify_area() 
in kernel 2.4
regards
Blesson Paul



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Re: put_user_byte()

[Brian Gerst]

blesson paul wrote:
> Hi all
>                I need to copy some data from kernel memory space to user 
> memory space. When I investigated, the command for that purpose is 
> put_user_byte(). But in kernel2.4, I can't find the implementation of 
> this command. I want to know the command which replaced put_user_byte() 
> in 2.4 kernel. Also I want to know whether there is any synonyms for 
> verify_area() in kernel 2.4
> regards
> Blesson Paul

Use put_user(val, uaddr).  val must be of type unsigned char (or casted 
to it).  It will return 0 on success or -EFAULT on fault.  verify_area() 
is normally not needed in 2.4, unless you are copying many values to 
user space and only want to do the priviledge check once on the whole range.

-- 

						Brian Gerst

Re: put_user_byte()

[Russell King]

On Thu, Apr 11, 2002 at 07:01:25AM -0400, Brian Gerst wrote:
> Use put_user(val, uaddr).

Correct.

> val must be of type unsigned char (or casted to it).

put_user does not care what value you pass it as val.  It only cares
about the type of uaddr.  The following are all equivalent as far as
the size of the data type written to user space:

	put_user((int)foo, (char *)bar);
	put_user((char)foo, (char *)bar);
	put_user((long)foo, (char *)bar);

-- 
Russell King (rmk@arm.linux.org.uk)                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html