From: Christian Kellner <christ...@kellner.me> The fdinfo file for a process file descriptor already contains the pid of the process in the callers namespaces. Additionally, if pid namespaces are configured, show the process ids of the process in all nested namespaces in the same format as in the procfs status file, i.e. "NSPid:\t%d\%d...". This allows the easy identification of the processes in nested namespaces.
Signed-off-by: Christian Kellner <christ...@kellner.me> --- kernel/fork.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/kernel/fork.c b/kernel/fork.c index 5a0fd518e04e..801793789f33 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1685,8 +1685,18 @@ static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) { struct pid_namespace *ns = proc_pid_ns(file_inode(m->file)); struct pid *pid = f->private_data; +#ifdef CONFIG_PID_NS + int i; +#endif seq_put_decimal_ull(m, "Pid:\t", pid_nr_ns(pid, ns)); +#ifdef CONFIG_PID_NS + seq_puts(m, "\nNSpid:"); + for (i = ns->level; i <= pid->level; i++) { + ns = pid_nr_ns(pid, pid->numbers[i].ns); + seq_put_decimal_ull(m, "\t", ns); + } +#endif seq_putc(m, '\n'); } #endif -- 2.21.0