Re: Asistence with sysctl proc's handle in kernel space

From: John Baldwin <jhb_at_FreeBSD.org>
Date: Wed, 31 Jul 2024 20:39:43 UTC
On 7/10/24 17:04, Nimbly2329 wrote:
> I am following FreeBSD drivers: A guide for the intrepid by Joseph Kong to
> learn to write FreeBSD device drivers.
> 
>    
> 
> I got to the sysctl subchapter where is more or less this code
> 
>    
> 
> #include <sys/param.h>
> 
> #include <sys/sysctl.h>
> 
>    
> 
> ....
> 
>    
> 
> static int sysctl_set_buffer_size(SYSCTL_HANDLER_ARGS) {
> 
> int error = 0;
> 
> int size = echo_message->buffer_size;
> 
> error = sysctl_handle_int(oidp, &size, 0, req);
> 
> if (error || !req->newptr || echo_message->buffer_size == size) return
> (error);
> 
> if (size >= 128 && size <= 512) {
> 
> echo_message->buffer = realloc(echo_message->buffer, size, M_ECHO, M_WAITOK);
> 
> echo_message->buffer_size = size;
> 
> if (echo_message->length >= size) {
> 
> echo_message->length = size - 1;
> 
> echo_message->buffer[size - 1] = '\0';
> 
> }
> 
> } else {
> 
> error = EINVAL;
> 
> }
> 
> return (error);
> 
> }
> 
>    
> 
> but when compiling I got the error:
> 
>    
> 
> error: call to undeclared function 'sysctl_int_handle'; ISO C99 and later do
> not support implicit function declarations [-Werror,-Wimplicit-function-
> declaration]
> 
> 167 | error = sysctl_int_handle(oidp, &size, 0, req);
> 

Your error here shows 'sysctl_int_handle' instead of 'sysctl_handle_int'

-- 
John Baldwin