diff options
| author | Iago López Galeiras <iago@endocode.com> | 2015-06-25 15:00:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-06-25 17:00:37 -0700 |
| commit | 2e13ba54a2682eea24918b87ad3edf70c2cf085b (patch) | |
| tree | faa1c51d66968fada40fc971c3c17d1a242c7857 /fs/proc | |
| parent | c2c0bb44620dece7ec97e28167e32c343da22867 (diff) | |
| download | linux-2e13ba54a2682eea24918b87ad3edf70c2cf085b.tar.bz2 | |
fs, proc: introduce CONFIG_PROC_CHILDREN
Commit 818411616baf ("fs, proc: introduce /proc/<pid>/task/<tid>/children
entry") introduced the children entry for checkpoint restore and the
file is only available on kernels configured with CONFIG_EXPERT and
CONFIG_CHECKPOINT_RESTORE.
This is available in most distributions (Fedora, Debian, Ubuntu, CoreOS)
because they usually enable CONFIG_EXPERT and CONFIG_CHECKPOINT_RESTORE.
But Arch does not enable CONFIG_EXPERT or CONFIG_CHECKPOINT_RESTORE.
However, the children proc file is useful outside of checkpoint restore.
I would like to use it in rkt. The rkt process exec() another program
it does not control, and that other program will fork()+exec() a child
process. I would like to find the pid of the child process from an
external tool without iterating in /proc over all processes to find
which one has a parent pid equal to rkt.
This commit introduces CONFIG_PROC_CHILDREN and makes
CONFIG_CHECKPOINT_RESTORE select it. This allows enabling
/proc/<pid>/task/<tid>/children without needing to enable
CONFIG_CHECKPOINT_RESTORE and CONFIG_EXPERT.
Alban tested that /proc/<pid>/task/<tid>/children is present when the
kernel is configured with CONFIG_PROC_CHILDREN=y but without
CONFIG_CHECKPOINT_RESTORE
Signed-off-by: Iago López Galeiras <iago@endocode.com>
Tested-by: Alban Crequy <alban@endocode.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: 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: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Djalal Harouni <djalal@endocode.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/Kconfig | 4 | ||||
| -rw-r--r-- | fs/proc/array.c | 4 | ||||
| -rw-r--r-- | fs/proc/base.c | 2 |
3 files changed, 7 insertions, 3 deletions
diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig index 2183fcf41d59..d751fcb637bb 100644 --- a/fs/proc/Kconfig +++ b/fs/proc/Kconfig @@ -71,3 +71,7 @@ config PROC_PAGE_MONITOR /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap, /proc/kpagecount, and /proc/kpageflags. Disabling these interfaces will reduce the size of the kernel by approximately 4kb. + +config PROC_CHILDREN + bool "Include /proc/<pid>/task/<tid>/children file" + default n diff --git a/fs/proc/array.c b/fs/proc/array.c index 3f57dac31ba6..ce065cf3104f 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -577,7 +577,7 @@ int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns, return 0; } -#ifdef CONFIG_CHECKPOINT_RESTORE +#ifdef CONFIG_PROC_CHILDREN static struct pid * get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos) { @@ -700,4 +700,4 @@ const struct file_operations proc_tid_children_operations = { .llseek = seq_lseek, .release = children_seq_release, }; -#endif /* CONFIG_CHECKPOINT_RESTORE */ +#endif /* CONFIG_PROC_CHILDREN */ diff --git a/fs/proc/base.c b/fs/proc/base.c index bd7a9affc14b..1d540b3f226f 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3109,7 +3109,7 @@ static const struct pid_entry tid_base_stuff[] = { ONE("stat", S_IRUGO, proc_tid_stat), ONE("statm", S_IRUGO, proc_pid_statm), REG("maps", S_IRUGO, proc_tid_maps_operations), -#ifdef CONFIG_CHECKPOINT_RESTORE +#ifdef CONFIG_PROC_CHILDREN REG("children", S_IRUGO, proc_tid_children_operations), #endif #ifdef CONFIG_NUMA |