From: Alban Crequy <[email protected]> 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. Since the children proc file is useful outside of checkpoint-restore, I am removing the guard on CONFIG_CHECKPOINT_RESTORE. Signed-off-by: Alban Crequy <[email protected]> Cc: Iago Lopez Galeiras <[email protected]> --- fs/proc/array.c | 2 -- fs/proc/base.c | 2 -- 2 files changed, 4 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index fd02a9e..6edec57 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -569,7 +569,6 @@ int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns, return 0; } -#ifdef CONFIG_CHECKPOINT_RESTORE static struct pid * get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos) { @@ -692,4 +691,3 @@ const struct file_operations proc_tid_children_operations = { .llseek = seq_lseek, .release = children_seq_release, }; -#endif /* CONFIG_CHECKPOINT_RESTORE */ diff --git a/fs/proc/base.c b/fs/proc/base.c index 093ca14..b743007 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2922,9 +2922,7 @@ 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 REG("children", S_IRUGO, proc_tid_children_operations), -#endif #ifdef CONFIG_NUMA REG("numa_maps", S_IRUGO, proc_tid_numa_maps_operations), #endif -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
