[resend][PATCH v9 2/3] /proc/PID/status: show all sets of pid according to ns

[Eric W. Biederman]

Chen Hanxiao <chenhanxiao at cn.fujitsu.com> writes:

> If some issues occurred inside a container guest, host user
> could not know which process is in trouble just by guest pid:
> the users of container guest only knew the pid inside containers.
> This will bring obstacle for trouble shooting.
>
> This patch adds four fields: NStgid, NSpid, NSpgid and NSsid:
> a) In init_pid_ns, nothing changed;
>
> b) In one pidns, will tell the pid inside containers:
>   NStgid: 21776   5       1
>   NSpid:  21776   5       1
>   NSpgid: 21776   5       1
>   NSsid:  21729   1       0
>   ** Process id is 21776 in level 0, 5 in level 1, 1 in level 2.
>
> c) If pidns is nested, it depends on which pidns are you in.
>   NStgid: 5       1
>   NSpid:  5       1
>   NSpgid: 5       1
>   NSsid:  1       0
>   ** Views from level 1
>
> Acked-by: Serge Hallyn <serge.hallyn at canonical.com>
> Tested-by: Serge Hallyn <serge.hallyn at canonical.com>
>
> Signed-off-by: Chen Hanxiao <chenhanxiao at cn.fujitsu.com>

Acked-by: "Eric W. Biederman" <ebiederm at xmission.com>

At a quick review and read through this looks good.  Once I finish
clearing the security bug fixes from my tree I will see about picking this
up.

Eric


> ---
> v9: rebased on 3.19-rc1
> No change from v4-v8
> v3: add another two fielsd: NSpgid and NSsid.
> v2: add two new fields: NStgid and NSpid.
>     keep fields of Tgid and Pid unchanged for back compatibility.
>
>  fs/proc/array.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/fs/proc/array.c b/fs/proc/array.c
> index bd117d0..35205d4 100644
> --- a/fs/proc/array.c
> +++ b/fs/proc/array.c
> @@ -208,6 +208,22 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
>  			   from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
>  	put_cred(cred);
>  
> +	seq_puts(m, "\nNStgid:");
> +	for (g = ns->level; g <= pid->level; g++)
> +		seq_printf(m, "\t%d ",
> +			task_tgid_nr_ns(p, pid->numbers[g].ns));
> +	seq_puts(m, "\nNSpid:");
> +	for (g = ns->level; g <= pid->level; g++)
> +		seq_printf(m, "\t%d ",
> +			task_pid_nr_ns(p, pid->numbers[g].ns));
> +	seq_puts(m, "\nNSpgid:");
> +	for (g = ns->level; g <= pid->level; g++)
> +		seq_printf(m, "\t%d ",
> +			task_pgrp_nr_ns(p, pid->numbers[g].ns));
> +	seq_puts(m, "\nNSsid:");
> +	for (g = ns->level; g <= pid->level; g++)
> +		seq_printf(m, "\t%d ",
> +			task_session_nr_ns(p, pid->numbers[g].ns));
>  	seq_putc(m, '\n');
>  }