c/r: procfs: add arg_start/end, env_start/end and exit_code members to /proc/$pid/stat

We would like to have an ability to restore command line arguments and
program environment pointers but first we need to obtain them somehow.
Thus we put these values into /proc/$pid/stat.  The exit_code is needed to
restore zombie tasks.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 3 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 62887e39a2de..c1c207c36cae 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -517,9 +517,23 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
         seq_put_decimal_ull(m, ' ', delayacct_blkio_ticks(task));
         seq_put_decimal_ull(m, ' ', cputime_to_clock_t(gtime));
         seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cgtime));
-        seq_put_decimal_ull(m, ' ', (mm && permitted) ? mm->start_data : 0);
-        seq_put_decimal_ull(m, ' ', (mm && permitted) ? mm->end_data : 0);
-        seq_put_decimal_ull(m, ' ', (mm && permitted) ? mm->start_brk : 0);
+
+        if (mm && permitted) {
+                seq_put_decimal_ull(m, ' ', mm->start_data);
+                seq_put_decimal_ull(m, ' ', mm->end_data);
+                seq_put_decimal_ull(m, ' ', mm->start_brk);
+                seq_put_decimal_ull(m, ' ', mm->arg_start);
+                seq_put_decimal_ull(m, ' ', mm->arg_end);
+                seq_put_decimal_ull(m, ' ', mm->env_start);
+                seq_put_decimal_ull(m, ' ', mm->env_end);
+        } else
+                seq_printf(m, " 0 0 0 0 0 0 0");
+
+        if (permitted)
+                seq_put_decimal_ll(m, ' ', task->exit_code);
+        else
+                seq_put_decimal_ll(m, ' ', 0);
+
         seq_putc(m, '\n');
         if (mm)
                 mmput(mm);