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* New proc entry under /proc/[pid]
@ 2011-01-10 17:18 Mauro Romano Trajber
  2011-01-10 18:49 ` Mauro Romano Trajber
  0 siblings, 1 reply; 6+ messages in thread
From: Mauro Romano Trajber @ 2011-01-10 17:18 UTC (permalink / raw)
  To: kernelnewbies

How can I create a new proc entry under /proc/[pid] ?
I using create_proc_entry("SOME_FILE", 0644, NULL /* here goes the pid proc
entry */);
Is there any way to get PID directory as a parent proc entry ? How ?

Thanks,
Mauro
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* New proc entry under /proc/[pid]
  2011-01-10 17:18 New proc entry under /proc/[pid] Mauro Romano Trajber
@ 2011-01-10 18:49 ` Mauro Romano Trajber
  2011-01-11  6:39   ` Rajat Sharma
  0 siblings, 1 reply; 6+ messages in thread
From: Mauro Romano Trajber @ 2011-01-10 18:49 UTC (permalink / raw)
  To: kernelnewbies

I think I found:
static const struct pid_entry tgid_base_stuff[] at fs/proc/base.c has all
/proc/[pid] entries.

But unfortunately it does not use create_proc_entry function, and I'm trying
to create a new syscall that creates a new proc_entry for the caller
process.
Adding a new element in tgid_base_stuff[] makes the things more complicated
than simply call a create_proc_entry function.

Is there another way to do it ?

Mauro Romano Trajber

On Mon, Jan 10, 2011 at 3:18 PM, Mauro Romano Trajber <trajber@gmail.com>wrote:

> How can I create a new proc entry under /proc/[pid] ?
> I using create_proc_entry("SOME_FILE", 0644, NULL /* here goes the pid proc
> entry */);
> Is there any way to get PID directory as a parent proc entry ? How ?
>
> Thanks,
> Mauro
>
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^ permalink raw reply	[flat|nested] 6+ messages in thread
* New proc entry under /proc/[pid]
  2011-01-10 18:49 ` Mauro Romano Trajber
@ 2011-01-11  6:39   ` Rajat Sharma
  2011-01-11 19:20     ` Mauro Romano Trajber
  0 siblings, 1 reply; 6+ messages in thread
From: Rajat Sharma @ 2011-01-11  6:39 UTC (permalink / raw)
  To: kernelnewbies

Try this:
1. do a path_lookup for parent proc dir e.g. /proc/1234 and get its inode.
2. get proc_inode structure for parent from vfs inode like this:
          sruct proc_inode *parent = PROC_I(inode).
    PROC_I is defined in proc_fs.h
3. get parent proc_dir_entry object:
          struct proc_dir_entry *parent_dir = parent->pde;
4. now you can call:
          create_proc_entry("SOME file", 0644, parent_dir);
5. or you can create a directory if you want:
          proc_mkdir("your dir", parent_dir);

hope this helps.

Rajat

On Tue, Jan 11, 2011 at 12:19 AM, Mauro Romano Trajber
<trajber@gmail.com> wrote:
> I think I found:
> static const struct pid_entry tgid_base_stuff[] at fs/proc/base.c?has all
> /proc/[pid] entries.
> But unfortunately it does not use create_proc_entry function, and I'm trying
> to create a new syscall that creates a new proc_entry for the caller
> process.
> Adding a new element in?tgid_base_stuff[] makes the things more complicated
> than simply call a create_proc_entry function.
> Is there another way to do it ?
> Mauro Romano Trajber
>
> On Mon, Jan 10, 2011 at 3:18 PM, Mauro Romano Trajber <trajber@gmail.com>
> wrote:
>>
>> How can I create a new proc entry under /proc/[pid] ?
>> I using create_proc_entry("SOME_FILE", 0644, NULL /* here goes the pid
>> proc entry */);
>> Is there any way to get PID directory as a parent proc entry ? How ?
>> Thanks,
>> Mauro
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>

^ permalink raw reply	[flat|nested] 6+ messages in thread
* New proc entry under /proc/[pid]
  2011-01-11  6:39   ` Rajat Sharma
@ 2011-01-11 19:20     ` Mauro Romano Trajber
  2011-01-12  9:41       ` Rajat Sharma
  0 siblings, 1 reply; 6+ messages in thread
From: Mauro Romano Trajber @ 2011-01-11 19:20 UTC (permalink / raw)
  To: kernelnewbies

Following your recommendations parent->pde always returns NULL. You know why
?

// code...
err = kern_path("/proc/1/", LOOKUP_FOLLOW, &path);
 if (err) {
return err;
}
 struct proc_inode *parent = PROC_I(path.dentry->d_inode);
struct proc_dir_entry *parent_dir = parent->pde;
 if (parent_dir == NULL) {
printk("parent_dir is NULL\n");
} else {
 create_proc_entry("SOMEFile", 0644, parent_dir);
}


Mauro!

On Tue, Jan 11, 2011 at 4:39 AM, Rajat Sharma <fs.rajat@gmail.com> wrote:

> Try this:
> 1. do a path_lookup for parent proc dir e.g. /proc/1234 and get its inode.
> 2. get proc_inode structure for parent from vfs inode like this:
>          sruct proc_inode *parent = PROC_I(inode).
>    PROC_I is defined in proc_fs.h
> 3. get parent proc_dir_entry object:
>          struct proc_dir_entry *parent_dir = parent->pde;
> 4. now you can call:
>          create_proc_entry("SOME file", 0644, parent_dir);
> 5. or you can create a directory if you want:
>          proc_mkdir("your dir", parent_dir);
>
> hope this helps.
>
> Rajat
>
> On Tue, Jan 11, 2011 at 12:19 AM, Mauro Romano Trajber
> <trajber@gmail.com> wrote:
> > I think I found:
> > static const struct pid_entry tgid_base_stuff[] at fs/proc/base.c has all
> > /proc/[pid] entries.
> > But unfortunately it does not use create_proc_entry function, and I'm
> trying
> > to create a new syscall that creates a new proc_entry for the caller
> > process.
> > Adding a new element in tgid_base_stuff[] makes the things more
> complicated
> > than simply call a create_proc_entry function.
> > Is there another way to do it ?
> > Mauro Romano Trajber
> >
> > On Mon, Jan 10, 2011 at 3:18 PM, Mauro Romano Trajber <trajber@gmail.com
> >
> > wrote:
> >>
> >> How can I create a new proc entry under /proc/[pid] ?
> >> I using create_proc_entry("SOME_FILE", 0644, NULL /* here goes the pid
> >> proc entry */);
> >> Is there any way to get PID directory as a parent proc entry ? How ?
> >> Thanks,
> >> Mauro
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
> >
>
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^ permalink raw reply	[flat|nested] 6+ messages in thread
* New proc entry under /proc/[pid]
  2011-01-11 19:20     ` Mauro Romano Trajber
@ 2011-01-12  9:41       ` Rajat Sharma
  2011-01-12 18:58         ` Mauro Romano Trajber
  0 siblings, 1 reply; 6+ messages in thread
From: Rajat Sharma @ 2011-01-12  9:41 UTC (permalink / raw)
  To: kernelnewbies

yes you are right, it gives NULL for <pid> directories under proc but
I tried changing pid to something else, say /proc/sys and it works.
Looks like handling of pid directories is entirely different. I didn't
get time to explore on that, will have to dig more into this.

Rajat

On Wed, Jan 12, 2011 at 12:50 AM, Mauro Romano Trajber
<trajber@gmail.com> wrote:
> Following your?recommendations?parent->pde always returns NULL. You know why
> ?
> // code...
> err = kern_path("/proc/1/", LOOKUP_FOLLOW, &path);
> if (err) {
> return err;
> }
> struct proc_inode *parent = PROC_I(path.dentry->d_inode);
> struct proc_dir_entry *parent_dir = parent->pde;
> if (parent_dir == NULL) {
> printk("parent_dir is NULL\n");
> } else {
> create_proc_entry("SOMEFile", 0644, parent_dir);
> }
>
> Mauro!
> On Tue, Jan 11, 2011 at 4:39 AM, Rajat Sharma <fs.rajat@gmail.com> wrote:
>>
>> Try this:
>> 1. do a path_lookup for parent proc dir e.g. /proc/1234 and get its inode.
>> 2. get proc_inode structure for parent from vfs inode like this:
>> ? ? ? ? ?sruct proc_inode *parent = PROC_I(inode).
>> ? ?PROC_I is defined in proc_fs.h
>> 3. get parent proc_dir_entry object:
>> ? ? ? ? ?struct proc_dir_entry *parent_dir = parent->pde;
>> 4. now you can call:
>> ? ? ? ? ?create_proc_entry("SOME file", 0644, parent_dir);
>> 5. or you can create a directory if you want:
>> ? ? ? ? ?proc_mkdir("your dir", parent_dir);
>>
>> hope this helps.
>>
>> Rajat
>>
>> On Tue, Jan 11, 2011 at 12:19 AM, Mauro Romano Trajber
>> <trajber@gmail.com> wrote:
>> > I think I found:
>> > static const struct pid_entry tgid_base_stuff[] at fs/proc/base.c?has
>> > all
>> > /proc/[pid] entries.
>> > But unfortunately it does not use create_proc_entry function, and I'm
>> > trying
>> > to create a new syscall that creates a new proc_entry for the caller
>> > process.
>> > Adding a new element in?tgid_base_stuff[] makes the things more
>> > complicated
>> > than simply call a create_proc_entry function.
>> > Is there another way to do it ?
>> > Mauro Romano Trajber
>> >
>> > On Mon, Jan 10, 2011 at 3:18 PM, Mauro Romano Trajber
>> > <trajber@gmail.com>
>> > wrote:
>> >>
>> >> How can I create a new proc entry under /proc/[pid] ?
>> >> I using create_proc_entry("SOME_FILE", 0644, NULL /* here goes the pid
>> >> proc entry */);
>> >> Is there any way to get PID directory as a parent proc entry ? How ?
>> >> Thanks,
>> >> Mauro
>> >
>> > _______________________________________________
>> > Kernelnewbies mailing list
>> > Kernelnewbies at kernelnewbies.org
>> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>> >
>> >
>
>

^ permalink raw reply	[flat|nested] 6+ messages in thread
* New proc entry under /proc/[pid]
  2011-01-12  9:41       ` Rajat Sharma
@ 2011-01-12 18:58         ` Mauro Romano Trajber
  0 siblings, 0 replies; 6+ messages in thread
From: Mauro Romano Trajber @ 2011-01-12 18:58 UTC (permalink / raw)
  To: kernelnewbies

Yes, /proc/[pid] handling is diferent and your solution is perfect just for
the other proc directories.

Informations under [pid] directories are about tasks (processes), and most
of this information is represented by task_struct structure (defined
in include/linux/sched.h).

I think one easy way to solve this problem is:

In include/linux/sched.h file
1 - add a new element in task_struct structure.
struct task_struct {
int my_value;
        .......

In  fs/proc/base.c file
1 - Create a new entry in static pid_entry tgid_base_stuff[] array.
e.g.  ONE("MY_FILE", S_IRUSR, proc_pid_my_file),

2 - Create a callback function that will be invoked when the new proc entry
is accessed (*task_struct is passed to this function).
static int proc_pid_my_file(struct seq_file *m, struct pid_namespace *ns,
 struct pid *pid, struct task_struct *task)
{
seq_printf(m, "%s %d\n", "here we go....", task->my_value);
 return 0;
}


Use the task_struct as usual:
struct task_struct *task;
 task = pid_task(find_vpid(1), PIDTYPE_PID);


I don't know if it is the best solution, but it seems it worked.
If anyone know a more easy or correct solution please let me know.

Thanks again,
Mauro Romano Trajber

On Wed, Jan 12, 2011 at 7:41 AM, Rajat Sharma <fs.rajat@gmail.com> wrote:

> yes you are right, it gives NULL for <pid> directories under proc but
> I tried changing pid to something else, say /proc/sys and it works.
> Looks like handling of pid directories is entirely different. I didn't
> get time to explore on that, will have to dig more into this.
>
> Rajat
>
> On Wed, Jan 12, 2011 at 12:50 AM, Mauro Romano Trajber
> <trajber@gmail.com> wrote:
> > Following your recommendations parent->pde always returns NULL. You know
> why
> > ?
> > // code...
> > err = kern_path("/proc/1/", LOOKUP_FOLLOW, &path);
> > if (err) {
> > return err;
> > }
> > struct proc_inode *parent = PROC_I(path.dentry->d_inode);
> > struct proc_dir_entry *parent_dir = parent->pde;
> > if (parent_dir == NULL) {
> > printk("parent_dir is NULL\n");
> > } else {
> > create_proc_entry("SOMEFile", 0644, parent_dir);
> > }
> >
> > Mauro!
> > On Tue, Jan 11, 2011 at 4:39 AM, Rajat Sharma <fs.rajat@gmail.com>
> wrote:
> >>
> >> Try this:
> >> 1. do a path_lookup for parent proc dir e.g. /proc/1234 and get its
> inode.
> >> 2. get proc_inode structure for parent from vfs inode like this:
> >>          sruct proc_inode *parent = PROC_I(inode).
> >>    PROC_I is defined in proc_fs.h
> >> 3. get parent proc_dir_entry object:
> >>          struct proc_dir_entry *parent_dir = parent->pde;
> >> 4. now you can call:
> >>          create_proc_entry("SOME file", 0644, parent_dir);
> >> 5. or you can create a directory if you want:
> >>          proc_mkdir("your dir", parent_dir);
> >>
> >> hope this helps.
> >>
> >> Rajat
> >>
> >> On Tue, Jan 11, 2011 at 12:19 AM, Mauro Romano Trajber
> >> <trajber@gmail.com> wrote:
> >> > I think I found:
> >> > static const struct pid_entry tgid_base_stuff[] at fs/proc/base.c has
> >> > all
> >> > /proc/[pid] entries.
> >> > But unfortunately it does not use create_proc_entry function, and I'm
> >> > trying
> >> > to create a new syscall that creates a new proc_entry for the caller
> >> > process.
> >> > Adding a new element in tgid_base_stuff[] makes the things more
> >> > complicated
> >> > than simply call a create_proc_entry function.
> >> > Is there another way to do it ?
> >> > Mauro Romano Trajber
> >> >
> >> > On Mon, Jan 10, 2011 at 3:18 PM, Mauro Romano Trajber
> >> > <trajber@gmail.com>
> >> > wrote:
> >> >>
> >> >> How can I create a new proc entry under /proc/[pid] ?
> >> >> I using create_proc_entry("SOME_FILE", 0644, NULL /* here goes the
> pid
> >> >> proc entry */);
> >> >> Is there any way to get PID directory as a parent proc entry ? How ?
> >> >> Thanks,
> >> >> Mauro
> >> >
> >> > _______________________________________________
> >> > Kernelnewbies mailing list
> >> > Kernelnewbies at kernelnewbies.org
> >> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >> >
> >> >
> >
> >
>
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Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-01-10 17:18 New proc entry under /proc/[pid] Mauro Romano Trajber
2011-01-10 18:49 ` Mauro Romano Trajber
2011-01-11  6:39   ` Rajat Sharma
2011-01-11 19:20     ` Mauro Romano Trajber
2011-01-12  9:41       ` Rajat Sharma
2011-01-12 18:58         ` Mauro Romano Trajber

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