Messages in this thread | | | Date | Fri, 27 Jan 2012 15:00:37 -0500 | From | KOSAKI Motohiro <> | Subject | Re: [RFC c/r 3/4] c/r: procfs: add arg_start/end, env_start/end and exit_code members to /proc/$pid/stat |
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On 1/27/2012 12:53 PM, Cyrill Gorcunov wrote: > 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> > Cc: Pavel Emelyanov <xemul@parallels.com> > Cc: Serge Hallyn <serge.hallyn@canonical.com> > Cc: Kees Cook <keescook@chromium.org> > 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 | 23 ++++++++++++++++++----- > 2 files changed, 23 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 +511,23 @@ 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 "); > + }
This part seems good.
> + > + seq_printf(m, "%d\n", task->exit_code); > +
Bad this part seems to make new side channel. exit_code is one of inter process communication messages. IPC messages should NOT be observed from completely unrelated proesses.
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