Re: [PATCH] /proc/pid/status: show all sets of pid according to ns

From: Richard Weinberger
Date: Mon May 26 2014 - 07:09:47 EST


On Mon, May 26, 2014 at 12:05 PM, Chen Hanxiao
<chenhanxiao@xxxxxxxxxxxxxx> wrote:
> We need a direct method of getting the pid inside containers.
> 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 expands fields of Tgid and Pid:
> a) In init_pid_ns, nothing changed;
>
> b) In one pidns, they will tell the pid inside containers:
> Tgid: 1628 9 3
> Pid: 1628 9 3
> ** process id is 1628 in level 0, 9 in level 1, 3 in level 2.
>
> c) If pidns is nested, it depends on which pidns are you in.
> Tgid: 9 3
> Pid: 9 3
> ** Views from level 1 for Pid 1628 in host.
>
> Signed-off-by: Chen Hanxiao <chenhanxiao@xxxxxxxxxxxxxx>
> ---
> fs/proc/array.c | 20 +++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/fs/proc/array.c b/fs/proc/array.c
> index 64db2bc..eef20dd 100644
> --- a/fs/proc/array.c
> +++ b/fs/proc/array.c
> @@ -173,17 +173,23 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
> cred = get_task_cred(p);
> seq_printf(m,
> "State:\t%s\n"
> - "Tgid:\t%d\n"
> - "Ngid:\t%d\n"
> - "Pid:\t%d\n"
> + "Ngid:\t%d\n",

You're changing the ordering of Tgid and Ngid here.

> + get_task_state(p),
> + task_numa_group_id(p));
> + seq_puts(m, "Tgid:");
> + for (g = ns->level; g <= pid->level; g++)
> + seq_printf(m, "\t%d ",
> + task_tgid_nr_ns(p, pid->numbers[g].ns));

I like the idea but IMHO we should keep Tgid and Pid as is and better
add two new fields to /proc/pid/status.
What about NSpid and NSgid?

> + seq_puts(m, "\nPid:");
> + for (g = ns->level; g <= pid->level; g++)
> + seq_printf(m, "\t%d ",
> + task_pid_nr_ns(p, pid->numbers[g].ns));
> + seq_putc(m, '\n');
> + seq_printf(m,
> "PPid:\t%d\n"
> "TracerPid:\t%d\n"
> "Uid:\t%d\t%d\t%d\t%d\n"
> "Gid:\t%d\t%d\t%d\t%d\n",
> - get_task_state(p),
> - task_tgid_nr_ns(p, ns),
> - task_numa_group_id(p),
> - pid_nr_ns(pid, ns),
> ppid, tpid,
> from_kuid_munged(user_ns, cred->uid),
> from_kuid_munged(user_ns, cred->euid),
> --
> 1.9.0
>
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--
Thanks,
//richard
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