Quick Syscall question

Quick Syscall question

[Eric Bambach]

Hello,

	This may seem like a silly question, however we were all beginning 
programmers once ;)

	I want to do some manipulating of network interfaces and routing and such. I 
am reading through some of the linux net sources but am confused on what are 
internal, kernel-only functions and what are externally visable syscalls. How 
can I tell from the source what is user-space visable that I can hook into 
and what is intternel stuff? Should I just be looking at headers or do I have 
to delve into the .c sources? I can do either, I just need a pointer on where 
to start and what I should be looking for.

Thanks
-- 

-EB

Re: Quick Syscall question

[Randy.Dunlap]

On Sun, 5 Sep 2004 13:17:42 -0500 Eric Bambach wrote:

| Hello,
| 
| 	This may seem like a silly question, however we were all beginning 
| programmers once ;)
| 
| 	I want to do some manipulating of network interfaces and routing and such. I 
| am reading through some of the linux net sources but am confused on what are 
| internal, kernel-only functions and what are externally visable syscalls. How 
| can I tell from the source what is user-space visable that I can hook into 
| and what is intternel stuff? Should I just be looking at headers or do I have 
| to delve into the .c sources? I can do either, I just need a pointer on where 
| to start and what I should be looking for.

Most syscalls are listed in include/linux/syscalls.h.
Also look in include/asm-*/unistd.h.
Also in entry.S in arch/*/ (various sub-directory levels).

--
~Randy

Re: Quick Syscall question

[Neil Horman]

Randy.Dunlap wrote:

>On Sun, 5 Sep 2004 13:17:42 -0500 Eric Bambach wrote:
>
>| Hello,
>| 
>| 	This may seem like a silly question, however we were all beginning 
>| programmers once ;)
>| 
>| 	I want to do some manipulating of network interfaces and routing and such. I 
>| am reading through some of the linux net sources but am confused on what are 
>| internal, kernel-only functions and what are externally visable syscalls. How 
>| can I tell from the source what is user-space visable that I can hook into 
>| and what is intternel stuff? Should I just be looking at headers or do I have 
>| to delve into the .c sources? I can do either, I just need a pointer on where 
>| to start and what I should be looking for.
>
>Most syscalls are listed in include/linux/syscalls.h.
>Also look in include/asm-*/unistd.h.
>Also in entry.S in arch/*/ (various sub-directory levels).
>
>--
>~Randy
>-
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Also, if you're looking into writing kernel modules, anything listed in 
arch/*ksyms.c as a symbol inside an EXPORT_SYMBOL block is accessible, 
although that may not mean its available from user space.
Neil

-- 
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 *Neil Horman
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 *nhorman@redhat.com
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