nsfs: generalize ns_get_path() for path resolution with a task

ns_get_path() takes struct task_struct and proc_ns_ops as its
parameters.  For path resolution directly from a namespace,
e.g. based on a networking device's net name space, we need
more flexibility.  Add a ns_get_path_cb() helper which will
allow callers to use any method of obtaining the name space
reference.  Convert ns_get_path() to use ns_get_path_cb().

Following patches will bring a networking user.

CC: Eric W. Biederman <ebiederm@xmission.com>
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Jakub Kicinski 2017-12-27 18:39:08 -08:00 committed by Daniel Borkmann
parent ad8ad79f4f
commit cdab6ba866
2 changed files with 29 additions and 3 deletions

View File

@ -103,14 +103,14 @@ static void *__ns_get_path(struct path *path, struct ns_common *ns)
goto got_it;
}
void *ns_get_path(struct path *path, struct task_struct *task,
const struct proc_ns_operations *ns_ops)
void *ns_get_path_cb(struct path *path, ns_get_path_helper_t *ns_get_cb,
void *private_data)
{
struct ns_common *ns;
void *ret;
again:
ns = ns_ops->get(task);
ns = ns_get_cb(private_data);
if (!ns)
return ERR_PTR(-ENOENT);
@ -120,6 +120,29 @@ void *ns_get_path(struct path *path, struct task_struct *task,
return ret;
}
struct ns_get_path_task_args {
const struct proc_ns_operations *ns_ops;
struct task_struct *task;
};
static struct ns_common *ns_get_path_task(void *private_data)
{
struct ns_get_path_task_args *args = private_data;
return args->ns_ops->get(args->task);
}
void *ns_get_path(struct path *path, struct task_struct *task,
const struct proc_ns_operations *ns_ops)
{
struct ns_get_path_task_args args = {
.ns_ops = ns_ops,
.task = task,
};
return ns_get_path_cb(path, ns_get_path_task, &args);
}
int open_related_ns(struct ns_common *ns,
struct ns_common *(*get_ns)(struct ns_common *ns))
{

View File

@ -78,6 +78,9 @@ extern struct file *proc_ns_fget(int fd);
#define get_proc_ns(inode) ((struct ns_common *)(inode)->i_private)
extern void *ns_get_path(struct path *path, struct task_struct *task,
const struct proc_ns_operations *ns_ops);
typedef struct ns_common *ns_get_path_helper_t(void *);
extern void *ns_get_path_cb(struct path *path, ns_get_path_helper_t ns_get_cb,
void *private_data);
extern int ns_get_name(char *buf, size_t size, struct task_struct *task,
const struct proc_ns_operations *ns_ops);