Re: Can linux kernel claim it uses GPL v2?

[kero552]

Alfred M. Szmidt wrote:
>    I don't  see any difference between
>    * "talk to Linux through syscalls"
>    * "using dlopen, dlsym and all this stuff" in both cases I dont require
>    compier to do anything, but there is a way to ask GPL code to do your
>    stuff. Quite a simillar.
>
> Do you see the difference between telnetd and telnet?  This is how
> glibc and Linux interaction looks like.

Communication between glibc and kernel. for writing a text
--- Fig. 1 ---------------------------------------------------
# write our string to stdout
  movl    $4,%eax         # system call number (sys_write)
  movl    $1,%ebx         # first argument: file handle (stdout)
  movl    $msg,%ecx       # second argument: pointer to message to
write
  movl    $len,%edx       # third argument: message length
  int     $0x80           # call kernel
--- code from http://linuxant.hit.bg/Assembly-HOWTO-6.html ---

Communication between program and and kernel on platform without
interrupts
--- Fig. 2 ---------------------------------------------------
# write our string to stdout
  movl    $4,%eax         # number of system call
  movl    $1,%ebx         # first argument: file handle (stdout)
  movl    $msg,%ecx       # second argument: pointer to message to
write
  movl    $len,%edx       # third argument: message length

  movl    [0x00A0],%efx   # load adress of syscall - syscall table
                          # is in memory from adress 0x0000. Each
                          # adress is 4 bytes long
  jump    %efx            # call kernel syscall number 4
--- code from http://linuxant.hit.bg/Assembly-HOWTO-6.html ---

Communication between program and library.
--- Fig. 3 ---------------------------------------------------
# write our string to stdout
  movl    $4,%eax         # number telling function what should it do.
In this case write a text
  movl    $1,%ebx         # first argument: file handle (stdout)
  movl    $msg,%ecx       # second argument: pointer to message to
write
  movl    $len,%edx       # third argument: message length
  movl    [%egx+0xA],%efx # in register %egx is base address of
                          # functions table. Each
                          # address is 4 bytes long
  jump    %efx            # call function print of dynamic library
--- code from http://linuxant.hit.bg/Assembly-HOWTO-6.html ---

... nope, dont see the difference. In both cases I fill some registers
and jump to specified place. The only difference is that since kernel
is always in memory, I defined a memory range for its function adress
table, while program can stay on hard drive, so its memory range for
functions will be dynamic.

>    I think that you can use GPL through linking. Why? because kernel
>    does it and I dont see difference between two lines above.
>
> Linux does not, please stop insisting that it does.
>
The moment I will stop will be moment I will understand it. Actually I
am lying I will stop now because this leads nowhere.

It is clear that you do not got my point and I as it seems nor did I
got yours. If after 57 mails I still don't get it. Quite a bad message,
at least for my brain.

I am really gratefull to all of you for showing me the correct way and
for spending your time on your answers, however it seems that I am
blind. And not persistent enough.

I am especially gratefull to Alexander Terekhov for providing me with
link to softwarecombinations060403.pdf, I will definitelly read it.