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Dear Livia,
Under Linux (as in any other UNIX-like OS) processes are created by means
of fork(2) system call. All system calls are prefixed with sys_ so, the
implementation of fork() is in sys_fork() function which is in
arch/i386/kernel/process.c file. If you build tags by means of this small
dotags script attached (from Pete Wyckoff), then you can easily lookup
things with:
vi -t sys_fork
Alternatively, you can compile the kernel with -g added to CFLAGS and use
gdb's list command to quickly lookup stuff.
As for termination, the system call _exit(2) is implemented in sys_exit()
(ok, it should be sys__exit() but that would be silly, so it is an
exception) of kernel/exit.c. A process can also terminate by a signal.
By looking at the sys_call_table[] of arch/i386/kernel/entry.S you can
learn how the sys_fork() function "becomes" a system call. It is also
instructive to notice the use of int 0x80 instruction to switch from user
to kernel mode when a system call is executed. This is in
include/asm-i386/unistd.h file, look at the _syscall*() macros.
Regards,
------
Tigran A. Aivazian | http://www.sco.com
Escalations Research Group | tel: +44-(0)1923-813796
Santa Cruz Operation Ltd | http://www.aivazian.demon.co.uk
Livia Catarina Soares said thus:
>Dear Colleagues
> I am here again with more questions.
> At this time my subject is: creation and termination process.
> QUESTION: Where did these procedures start??
> I mean ...Which is the first function called in both procedures??
> I am trying to understand the sequence of functions used in both
> procedures.
> I know that the main functions are do_fork and do_exit, respectively.
> However I could not trace all the behaviour.
> I would like to determine the exact point where a process is started and
> ended. I mean...the instant where the kernel realize that a
> process is started and ended.
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Content-Description: dotags script - useful for building kernel ctags
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