ns: proc files for namespace naming policy.
Create files under /proc/<pid>/ns/ to allow controlling the
namespaces of a process.
This addresses three specific problems that can make namespaces hard to
work with.
- Namespaces require a dedicated process to pin them in memory.
- It is not possible to use a namespace unless you are the child
of the original creator.
- Namespaces don't have names that userspace can use to talk about
them.
The namespace files under /proc/<pid>/ns/ can be opened and the
file descriptor can be used to talk about a specific namespace, and
to keep the specified namespace alive.
A namespace can be kept alive by either holding the file descriptor
open or bind mounting the file someplace else. aka:
mount --bind /proc/self/ns/net /some/filesystem/path
mount --bind /proc/self/fd/<N> /some/filesystem/path
This allows namespaces to be named with userspace policy.
It requires additional support to make use of these filedescriptors
and that will be comming in the following patches.
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 838c114..a6d2c6d 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -179,6 +179,8 @@
extern struct file *get_mm_exe_file(struct mm_struct *mm);
extern void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm);
+extern struct file *proc_ns_fget(int fd);
+
#else
#define proc_net_fops_create(net, name, mode, fops) ({ (void)(mode), NULL; })
@@ -239,6 +241,11 @@
struct mm_struct *newmm)
{}
+static inline struct file *proc_ns_fget(int fd)
+{
+ return ERR_PTR(-EINVAL);
+}
+
#endif /* CONFIG_PROC_FS */
#if !defined(CONFIG_PROC_KCORE)
@@ -250,6 +257,15 @@
extern void kclist_add(struct kcore_list *, void *, size_t, int type);
#endif
+struct nsproxy;
+struct proc_ns_operations {
+ const char *name;
+ int type;
+ void *(*get)(struct task_struct *task);
+ void (*put)(void *ns);
+ int (*install)(struct nsproxy *nsproxy, void *ns);
+};
+
union proc_op {
int (*proc_get_link)(struct inode *, struct path *);
int (*proc_read)(struct task_struct *task, char *page);
@@ -268,6 +284,8 @@
struct proc_dir_entry *pde;
struct ctl_table_header *sysctl;
struct ctl_table *sysctl_entry;
+ void *ns;
+ const struct proc_ns_operations *ns_ops;
struct inode vfs_inode;
};