Subject: A question about include/linux/socket.h

From: Sinan Akpolat <[email-masked]>
Date: Wed, 28 Aug 2013 16:45:29 +0300

Hi,

I am writing CAN bus userspace code and I get a compiler error stating 
"sa_family_t is not defined" for "include/linux/can.h". sa_family_t is 
defined in include/linux/socket.h but it is not carried to userspace 
kernel headers.

  When I searched about it I saw that a similar problem in 
include/linux/netlink.h and include/linux/socket.h is fixed by the patch:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/include?id=6602a4baf4d1a73cc4685a39ef859e1c5ddf654c. 

I also read about UAPI but I can't use newer kernels.

I searched the kernel git repo but couldn't find a similar patch for 
can.h. When you search for "sa_family_t" in include/linux directory you 
can see it is used in more than 10 files and I guess none of those files 
will compile since they won't be able to find typedef sa_family_t (just 
like can.h).

So my question is:
- Does anyone remember a patch fixing this issue?
- Should the typedef sa_family_t moved to userspace kernel headers? Or 
should structs containing sa_family_t type variables moved away from 
user space?

I have been using the file manually defining sa_family_t but I wanted to 
ask. I am using kernel version 2.6.37 but I guess can.h file was 
unchanged until 3.5.

Thanks