[patch cr 3/4] c/r: procfs: add arg_start/end, env_start/end and exit_code members to /proc/$pid/stat

Cyrill Gorcunov
2012-01-30T14:19:05Z

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We would like to have an ability to restore command line
arguments and envirion pointers so the task being restored
would print appropriate values in /proc/pid/cmdline and
/proc/pid/envirion. The exit_code is needed to restore
zombie tasks.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-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>
---
Documentation/filesystems/proc.txt | 5 +++++
fs/proc/array.c | 25 ++++++++++++++++++++-----
2 files changed, 25 insertions(+), 5 deletions(-)

Index: linux-2.6.git/Documentation/filesystems/proc.txt
===================================================================
--- linux-2.6.git.orig/Documentation/filesystems/proc.txt
+++ linux-2.6.git/Documentation/filesystems/proc.txt
@@ -311,6 +311,11 @@ Table 1-4: Contents of the stat files (a
start_data address above which program data+bss is placed
end_data address below which program data+bss is placed
start_brk address above which program heap can be expanded with brk()
+ arg_start address above which program command line is placed
+ arg_end address below which program command line is placed
+ env_start address above which program environment is placed
+ env_end address below which program environment is placed
+ exit_code the thread's exit_code in the form reported by the waitpid system call
..............................................................................

The /proc/PID/maps file containing the currently mapped memory regions and
Index: linux-2.6.git/fs/proc/array.c
===================================================================
--- linux-2.6.git.orig/fs/proc/array.c
+++ linux-2.6.git/fs/proc/array.c
@@ -464,7 +464,7 @@ static int do_task_stat(struct seq_file

seq_printf(m, "%d (%s) %c %d %d %d %d %d %u %lu \
%lu %lu %lu %lu %lu %ld %ld %ld %ld %d 0 %llu %lu %ld %lu %lu %lu %lu %lu \
-%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu %lu %ld %lu %lu %lu\n",
+%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu %lu %ld ",
pid_nr_ns(pid, ns),
tcomm,
state,
@@ -511,10 +511,25 @@ static int do_task_stat(struct seq_file
task->policy,
(unsigned long long)delayacct_blkio_ticks(task),
cputime_to_clock_t(gtime),
- cputime_to_clock_t(cgtime),
- (mm && permitted) ? mm->start_data : 0,
- (mm && permitted) ? mm->end_data : 0,
- (mm && permitted) ? mm->start_brk : 0);
+ cputime_to_clock_t(cgtime));
+
+ if (mm && permitted) {
+ seq_printf(m, "%lu %lu %lu %lu %lu %lu %lu ",
+ mm->start_data,
+ mm->end_data,
+ mm->start_brk,
+ mm->arg_start,
+ mm->arg_end,
+ mm->env_start,
+ mm->env_end);
+ } else
+ seq_printf(m, "0 0 0 0 0 0 0 ");
+
+ if (permitted)
+ seq_printf(m, "%d\n", task->exit_code);
+ else
+ seq_printf(m, "0\n");
+
if (mm)
mmput(mm);
return 0;