[PATCH v10 1/2] /proc/PID/status: show all sets of pid according to ns

From: Chen Hanxiao
Date: Fri Feb 06 2015 - 05:46:18 EST


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@xxxxxxxxxxxxx>
Acked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>

Tested-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Tested-by: Nathan Scott <nathans@xxxxxxxxxx>

Signed-off-by: Chen Hanxiao <chenhanxiao@xxxxxxxxxxxxxx>
---
v10: remove trailing space of pid numbers "\t%d " -> "\t%d",
rebased on 3.19-rc7
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..f3e6d76 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');
}

--
2.1.0

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