Re: Re: How to get the pid of all children, grand children..../... of a process

[Taha Hafeez Siddiqi <tawushafeez@xxxxxxxxx>]

On Wed, 2006-05-31 at 17:25 +0200, tyler@xxxxxxxx wrote:
> On Tue, May 30, 2006 at 10:04:47PM -0700, Nish Aravamudan wrote:
> > On 31 May 2006 04:54:23 -0000, rohit  hooda <rohit13hooda@xxxxxxxxxxxxxx> wrote:
> > >
> > > On Wed, 31 May 2006 Taha Hafeez Siddiqi wrote :
> > >
> > > >On Tue, 2006-05-30 at 17:20 +0530, Gopala Krishna wrote:
> > > > >
> > > > >
> > > > >         Fortunately, here comes the proc filesystem !
> > > > >         So, you have the pid of the father process : look at the file
> > > > >         /proc/'ppid'/status there should be a fild ppid : you have the
> > > > >         pid of
> > > > >         your grand parent.
> > > > >         You can do a recursive function to find all the ancestors of
> > > > >         your
> > > > >         process.
> > > > >         This solution is quite annoying since you have to handle
> > > > >         files, but it
> > > > >         works.
> > > > >
> > > > >         If this solution is not acceptable for you, you can look at
> > > > >         the pstree
> > > > >         source code.
> > > > >
> > > > >         I don't know if you wanted to do that in your own programm or
> > > > >         just
> > > > >         wanted some soft to give you the entire tree (like pstree).
> > > > >         Anyway... :
> > > > >
> > > > >
> > > > > In My case, I knew only pid of the first process. I want the top down
> > > > > approach rather than the bottom up (i.e if I know child, I know
> > > > > parent. but, my requirement is to find out child and it's grand
> > > > > children, If I know the parent pid). Currently I am going through
> > > > > pstree code.
> > > > >
> > > > > Thanks and regards,
> > > > > Gopal.
> > > > >
> > > > >
> > > >
> > > >Hi all,
> > > >
> > > >I think there is another way.*
> > > >
> > > >You can get hold of your current, use its list to get hold of the
> > > >process structure and the up you go using the process->parent....
> > > >
> > > >It may not be the correct way, but I suppose surely it is one way of
> > > >doing it*.
> > >
> > >
> > > Well in kernel mode, if you have the PID of a process, from that you can have
> > >its task_struct and then you can iterate down to get the lists of its children and
> > >grand children and so on ... but over here we have to do things in user space n
> > >not in kernel space
> > 
> > Then please take it off this list (KERNELnewbies).
> > 
> > Thanks,
> > Nish
> > 
> 
> Well Taha wants to implement it in user space. But in someway, the
> process and procfs subsystems are close to the kernel. Don't say him to go away !:)
> 

Hi all,

Firstly, I am not the one asking the question :)

I gave the answer using a module, so if one needs a solution in user
space, he can use the module as a char device driver or implement it
using procfs and if one needs a solution in kernel then he is already at
the right place to use my idea ....

On the matter whether this is our (KernelNewbies) issue, I agree with
Nish that if whole solution has to be implemented in user space then the
question doesn't belong here.... :)

regards
Taha




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