[OpenAFS-devel] Solaris afs.rc file damage

Russ Allbery rra@stanford.edu
Tue, 08 May 2007 23:27:45 -0700


Dean Anderson <dean@av8.com> writes:
> On Tue, 8 May 2007, Russ Allbery wrote:

>> Uh, Linux as of right now, so far as I know, does not support either
>> dynamic linking of system calls *or* static linking of system calls.  I
>> believe you have to patch the kernel source to add a new system call.
>> System calls are not how you're supposed to interact with loadable
>> modules on Linux.

> According the linux HOWTO on loadable kernel modules, there are six
> things that loadable kernel modules are used for:  
> (http://tldp.org/HOWTO/Module-HOWTO/ section 2.5, last updated
> 2006-09-24)

> Device Drivers
> Filesystem Drivers
> System Calls
> Network Drivers
> TTY line disciplines
> Executable Interpreters.

> I didn't check the source code, so maybe the HOWTO is wrong.

Given that the only way that OpenAFS ever adds system calls now is by
locating the system call table by binary search in memory and patching it
at runtime, and given that in the very latest kernels the system call
table is now in a read-only memory segment, I'm pretty sure the HOWTO is
wrong.

-- 
Russ Allbery (rra@stanford.edu)             <http://www.eyrie.org/~eagle/>