>
>
>
> there isnt a concept called loadable system calls in linux.but u can add
> dynamically with out recompiling the kernel by directly doing changes in the
> sys_call_table.Note : is not portable.
>
>> 1) add an
>> entry in include/asm-i386/unistd.h 2) #insmod nrprocess.o
>
>
> No need to add an entry in unistd.h if u r planning to add the system call
> using a module.
>
>> but I don't see how the userland application know the new system call.
>
>
> use _syscallX(...,...) macros defined in unistd.h from the userland programs
>
>> Do I have to recompile the kernel? I wonder there is document which
>> explains that.
>
> No need to recompile.
>
> Others please clarify if i m wrong.
>
> regards,
> mohan.
>
>
mohan,
Thank for the info. But I still have a question.
In my userland code, I change new system call
our_sys_open("mytest", O_RDONLY, 0444); into
#include <unistd.h>
...
_syscall3(errno, "our_sys_open", name, "mytest", filename, O_RDONLY,
flags, 0444);
...
the compilation still gives me error: undefined reference to `_syscall3'
I guess there is something I am still missing,
-Hong
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