Unverified Commit 2b9a0f21 authored by Christian Brauner's avatar Christian Brauner
Browse files

ns: move namespace types into separate header 

Add a dedicated header for namespace types.

Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-1-e8a9264e0fb9@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent a67ee4e2

include/linux/ns/ns_common_types.h

0 → 100644
+205 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _LINUX_NS_COMMON_TYPES_H

#define _LINUX_NS_COMMON_TYPES_H



#include <linux/atomic.h>

#include <linux/rbtree.h>

#include <linux/refcount.h>

#include <linux/types.h>



struct cgroup_namespace;

struct dentry;

struct ipc_namespace;

struct mnt_namespace;

struct net;

struct pid_namespace;

struct proc_ns_operations;

struct time_namespace;

struct user_namespace;

struct uts_namespace;



extern struct cgroup_namespace init_cgroup_ns;

extern struct ipc_namespace init_ipc_ns;

extern struct mnt_namespace init_mnt_ns;

extern struct net init_net;

extern struct pid_namespace init_pid_ns;

extern struct time_namespace init_time_ns;

extern struct user_namespace init_user_ns;

extern struct uts_namespace init_uts_ns;



extern const struct proc_ns_operations cgroupns_operations;

extern const struct proc_ns_operations ipcns_operations;

extern const struct proc_ns_operations mntns_operations;

extern const struct proc_ns_operations netns_operations;

extern const struct proc_ns_operations pidns_operations;

extern const struct proc_ns_operations pidns_for_children_operations;

extern const struct proc_ns_operations timens_operations;

extern const struct proc_ns_operations timens_for_children_operations;

extern const struct proc_ns_operations userns_operations;

extern const struct proc_ns_operations utsns_operations;



/*

 * Namespace lifetimes are managed via a two-tier reference counting model:

 *

 * (1) __ns_ref (refcount_t): Main reference count tracking memory

 *     lifetime. Controls when the namespace structure itself is freed.

 *     It also pins the namespace on the namespace trees whereas (2)

 *     only regulates their visibility to userspace.

 *

 * (2) __ns_ref_active (atomic_t): Reference count tracking active users.

 *     Controls visibility of the namespace in the namespace trees.

 *     Any live task that uses the namespace (via nsproxy or cred) holds

 *     an active reference. Any open file descriptor or bind-mount of

 *     the namespace holds an active reference. Once all tasks have

 *     called exited their namespaces and all file descriptors and

 *     bind-mounts have been released the active reference count drops

 *     to zero and the namespace becomes inactive. IOW, the namespace

 *     cannot be listed or opened via file handles anymore.

 *

 *     Note that it is valid to transition from active to inactive and

 *     back from inactive to active e.g., when resurrecting an inactive

 *     namespace tree via the SIOCGSKNS ioctl().

 *

 * Relationship and lifecycle states:

 *

 * - Active (__ns_ref_active > 0):

 *   Namespace is actively used and visible to userspace. The namespace

 *   can be reopened via /proc/<pid>/ns/<ns_type>, via namespace file

 *   handles, or discovered via listns().

 *

 * - Inactive (__ns_ref_active == 0, __ns_ref > 0):

 *   No tasks are actively using the namespace and it isn't pinned by

 *   any bind-mounts or open file descriptors anymore. But the namespace

 *   is still kept alive by internal references. For example, the user

 *   namespace could be pinned by an open file through file->f_cred

 *   references when one of the now defunct tasks had opened a file and

 *   handed the file descriptor off to another process via a UNIX

 *   sockets. Such references keep the namespace structure alive through

 *   __ns_ref but will not hold an active reference.

 *

 * - Destroyed (__ns_ref == 0):

 *   No references remain. The namespace is removed from the tree and freed.

 *

 * State transitions:

 *

 * Active -> Inactive:

 *   When the last task using the namespace exits it drops its active

 *   references to all namespaces. However, user and pid namespaces

 *   remain accessible until the task has been reaped.

 *

 * Inactive -> Active:

 *   An inactive namespace tree might be resurrected due to e.g., the

 *   SIOCGSKNS ioctl() on a socket.

 *

 * Inactive -> Destroyed:

 *   When __ns_ref drops to zero the namespace is removed from the

 *   namespaces trees and the memory is freed (after RCU grace period).

 *

 * Initial namespaces:

 *   Boot-time namespaces (init_net, init_pid_ns, etc.) start with

 *   __ns_ref_active = 1 and remain active forever.

 */

struct ns_common {

	u32 ns_type;

	struct dentry *stashed;

	const struct proc_ns_operations *ops;

	unsigned int inum;

	refcount_t __ns_ref; /* do not use directly */

	union {

		struct {

			u64 ns_id;

			struct /* global namespace rbtree and list */ {

				struct rb_node ns_unified_tree_node;

				struct list_head ns_unified_list_node;

			};

			struct /* per type rbtree and list */ {

				struct rb_node ns_tree_node;

				struct list_head ns_list_node;

			};

			struct /* namespace ownership rbtree and list */ {

				struct rb_root ns_owner_tree; /* rbtree of namespaces owned by this namespace */

				struct list_head ns_owner; /* list of namespaces owned by this namespace */

				struct rb_node ns_owner_tree_node; /* node in the owner namespace's rbtree */

				struct list_head ns_owner_entry; /* node in the owner namespace's ns_owned list */

			};

			atomic_t __ns_ref_active; /* do not use directly */

		};

		struct rcu_head ns_rcu;

	};

};



#define to_ns_common(__ns)                                    \

	_Generic((__ns),                                      \

		struct cgroup_namespace *:       &(__ns)->ns, \

		const struct cgroup_namespace *: &(__ns)->ns, \

		struct ipc_namespace *:          &(__ns)->ns, \

		const struct ipc_namespace *:    &(__ns)->ns, \

		struct mnt_namespace *:          &(__ns)->ns, \

		const struct mnt_namespace *:    &(__ns)->ns, \

		struct net *:                    &(__ns)->ns, \

		const struct net *:              &(__ns)->ns, \

		struct pid_namespace *:          &(__ns)->ns, \

		const struct pid_namespace *:    &(__ns)->ns, \

		struct time_namespace *:         &(__ns)->ns, \

		const struct time_namespace *:   &(__ns)->ns, \

		struct user_namespace *:         &(__ns)->ns, \

		const struct user_namespace *:   &(__ns)->ns, \

		struct uts_namespace *:          &(__ns)->ns, \

		const struct uts_namespace *:    &(__ns)->ns)



#define ns_init_inum(__ns)                                     \

	_Generic((__ns),                                       \

		struct cgroup_namespace *: CGROUP_NS_INIT_INO, \

		struct ipc_namespace *:    IPC_NS_INIT_INO,    \

		struct mnt_namespace *:    MNT_NS_INIT_INO,    \

		struct net *:              NET_NS_INIT_INO,    \

		struct pid_namespace *:    PID_NS_INIT_INO,    \

		struct time_namespace *:   TIME_NS_INIT_INO,   \

		struct user_namespace *:   USER_NS_INIT_INO,   \

		struct uts_namespace *:    UTS_NS_INIT_INO)



#define ns_init_ns(__ns)                                    \

	_Generic((__ns),                                    \

		struct cgroup_namespace *: &init_cgroup_ns, \

		struct ipc_namespace *:    &init_ipc_ns,    \

		struct mnt_namespace *:    &init_mnt_ns,     \

		struct net *:              &init_net,       \

		struct pid_namespace *:    &init_pid_ns,    \

		struct time_namespace *:   &init_time_ns,   \

		struct user_namespace *:   &init_user_ns,   \

		struct uts_namespace *:    &init_uts_ns)



#define ns_init_id(__ns)						\

	_Generic((__ns),						\

		struct cgroup_namespace *:	CGROUP_NS_INIT_ID,	\

		struct ipc_namespace *:		IPC_NS_INIT_ID,		\

		struct mnt_namespace *:		MNT_NS_INIT_ID,		\

		struct net *:			NET_NS_INIT_ID,		\

		struct pid_namespace *:		PID_NS_INIT_ID,		\

		struct time_namespace *:	TIME_NS_INIT_ID,	\

		struct user_namespace *:	USER_NS_INIT_ID,	\

		struct uts_namespace *:		UTS_NS_INIT_ID)



#define to_ns_operations(__ns)                                                                         \

	_Generic((__ns),                                                                               \

		struct cgroup_namespace *: (IS_ENABLED(CONFIG_CGROUPS) ? &cgroupns_operations : NULL), \

		struct ipc_namespace *:    (IS_ENABLED(CONFIG_IPC_NS)  ? &ipcns_operations    : NULL), \

		struct mnt_namespace *:    &mntns_operations,                                          \

		struct net *:              (IS_ENABLED(CONFIG_NET_NS)  ? &netns_operations    : NULL), \

		struct pid_namespace *:    (IS_ENABLED(CONFIG_PID_NS)  ? &pidns_operations    : NULL), \

		struct time_namespace *:   (IS_ENABLED(CONFIG_TIME_NS) ? &timens_operations   : NULL), \

		struct user_namespace *:   (IS_ENABLED(CONFIG_USER_NS) ? &userns_operations   : NULL), \

		struct uts_namespace *:    (IS_ENABLED(CONFIG_UTS_NS)  ? &utsns_operations    : NULL))



#define ns_common_type(__ns)                                \

	_Generic((__ns),                                    \

		struct cgroup_namespace *: CLONE_NEWCGROUP, \

		struct ipc_namespace *:    CLONE_NEWIPC,    \

		struct mnt_namespace *:    CLONE_NEWNS,     \

		struct net *:              CLONE_NEWNET,    \

		struct pid_namespace *:    CLONE_NEWPID,    \

		struct time_namespace *:   CLONE_NEWTIME,   \

		struct user_namespace *:   CLONE_NEWUSER,   \

		struct uts_namespace *:    CLONE_NEWUTS)



#endif /* _LINUX_NS_COMMON_TYPES_H */

include/linux/ns_common.h

+1 −195
Original line number Diff line number Diff line
@@ -2,133 +2,12 @@ 
#ifndef _LINUX_NS_COMMON_H

#define _LINUX_NS_COMMON_H



#include <linux/ns/ns_common_types.h>

#include <linux/refcount.h>

#include <linux/rbtree.h>

#include <linux/vfsdebug.h>

#include <uapi/linux/sched.h>

#include <uapi/linux/nsfs.h>



struct proc_ns_operations;



struct cgroup_namespace;

struct ipc_namespace;

struct mnt_namespace;

struct net;

struct pid_namespace;

struct time_namespace;

struct user_namespace;

struct uts_namespace;



extern struct cgroup_namespace init_cgroup_ns;

extern struct ipc_namespace init_ipc_ns;

extern struct mnt_namespace init_mnt_ns;

extern struct net init_net;

extern struct pid_namespace init_pid_ns;

extern struct time_namespace init_time_ns;

extern struct user_namespace init_user_ns;

extern struct uts_namespace init_uts_ns;



extern const struct proc_ns_operations netns_operations;

extern const struct proc_ns_operations utsns_operations;

extern const struct proc_ns_operations ipcns_operations;

extern const struct proc_ns_operations pidns_operations;

extern const struct proc_ns_operations pidns_for_children_operations;

extern const struct proc_ns_operations userns_operations;

extern const struct proc_ns_operations mntns_operations;

extern const struct proc_ns_operations cgroupns_operations;

extern const struct proc_ns_operations timens_operations;

extern const struct proc_ns_operations timens_for_children_operations;



/*

 * Namespace lifetimes are managed via a two-tier reference counting model:

 *

 * (1) __ns_ref (refcount_t): Main reference count tracking memory

 *     lifetime. Controls when the namespace structure itself is freed.

 *     It also pins the namespace on the namespace trees whereas (2)

 *     only regulates their visibility to userspace.

 *

 * (2) __ns_ref_active (atomic_t): Reference count tracking active users.

 *     Controls visibility of the namespace in the namespace trees.

 *     Any live task that uses the namespace (via nsproxy or cred) holds

 *     an active reference. Any open file descriptor or bind-mount of

 *     the namespace holds an active reference. Once all tasks have

 *     called exited their namespaces and all file descriptors and

 *     bind-mounts have been released the active reference count drops

 *     to zero and the namespace becomes inactive. IOW, the namespace

 *     cannot be listed or opened via file handles anymore.

 *

 *     Note that it is valid to transition from active to inactive and

 *     back from inactive to active e.g., when resurrecting an inactive

 *     namespace tree via the SIOCGSKNS ioctl().

 *

 * Relationship and lifecycle states:

 *

 * - Active (__ns_ref_active > 0):

 *   Namespace is actively used and visible to userspace. The namespace

 *   can be reopened via /proc/<pid>/ns/<ns_type>, via namespace file

 *   handles, or discovered via listns().

 *

 * - Inactive (__ns_ref_active == 0, __ns_ref > 0):

 *   No tasks are actively using the namespace and it isn't pinned by

 *   any bind-mounts or open file descriptors anymore. But the namespace

 *   is still kept alive by internal references. For example, the user

 *   namespace could be pinned by an open file through file->f_cred

 *   references when one of the now defunct tasks had opened a file and

 *   handed the file descriptor off to another process via a UNIX

 *   sockets. Such references keep the namespace structure alive through

 *   __ns_ref but will not hold an active reference.

 *

 * - Destroyed (__ns_ref == 0):

 *   No references remain. The namespace is removed from the tree and freed.

 *

 * State transitions:

 *

 * Active -> Inactive:

 *   When the last task using the namespace exits it drops its active

 *   references to all namespaces. However, user and pid namespaces

 *   remain accessible until the task has been reaped.

 *

 * Inactive -> Active:

 *   An inactive namespace tree might be resurrected due to e.g., the

 *   SIOCGSKNS ioctl() on a socket.

 *

 * Inactive -> Destroyed:

 *   When __ns_ref drops to zero the namespace is removed from the

 *   namespaces trees and the memory is freed (after RCU grace period).

 *

 * Initial namespaces:

 *   Boot-time namespaces (init_net, init_pid_ns, etc.) start with

 *   __ns_ref_active = 1 and remain active forever.

 */

struct ns_common {

	u32 ns_type;

	struct dentry *stashed;

	const struct proc_ns_operations *ops;

	unsigned int inum;

	refcount_t __ns_ref; /* do not use directly */

	union {

		struct {

			u64 ns_id;

			struct /* global namespace rbtree and list */ {

				struct rb_node ns_unified_tree_node;

				struct list_head ns_unified_list_node;

			};

			struct /* per type rbtree and list */ {

				struct rb_node ns_tree_node;

				struct list_head ns_list_node;

			};

			struct /* namespace ownership rbtree and list */ {

				struct rb_root ns_owner_tree; /* rbtree of namespaces owned by this namespace */

				struct list_head ns_owner; /* list of namespaces owned by this namespace */

				struct rb_node ns_owner_tree_node; /* node in the owner namespace's rbtree */

				struct list_head ns_owner_entry; /* node in the owner namespace's ns_owned list */

			};

			atomic_t __ns_ref_active; /* do not use directly */

		};

		struct rcu_head ns_rcu;

	};

};



bool is_current_namespace(struct ns_common *ns);

int __ns_common_init(struct ns_common *ns, u32 ns_type, const struct proc_ns_operations *ops, int inum);

void __ns_common_free(struct ns_common *ns);
@@ -147,79 +26,6 @@ static __always_inline bool is_ns_init_id(const struct ns_common *ns) 
	return ns->ns_id <= NS_LAST_INIT_ID;

}



#define to_ns_common(__ns)                                    \

	_Generic((__ns),                                      \

		struct cgroup_namespace *:       &(__ns)->ns, \

		const struct cgroup_namespace *: &(__ns)->ns, \

		struct ipc_namespace *:          &(__ns)->ns, \

		const struct ipc_namespace *:    &(__ns)->ns, \

		struct mnt_namespace *:          &(__ns)->ns, \

		const struct mnt_namespace *:    &(__ns)->ns, \

		struct net *:                    &(__ns)->ns, \

		const struct net *:              &(__ns)->ns, \

		struct pid_namespace *:          &(__ns)->ns, \

		const struct pid_namespace *:    &(__ns)->ns, \

		struct time_namespace *:         &(__ns)->ns, \

		const struct time_namespace *:   &(__ns)->ns, \

		struct user_namespace *:         &(__ns)->ns, \

		const struct user_namespace *:   &(__ns)->ns, \

		struct uts_namespace *:          &(__ns)->ns, \

		const struct uts_namespace *:    &(__ns)->ns)



#define ns_init_inum(__ns)                                     \

	_Generic((__ns),                                       \

		struct cgroup_namespace *: CGROUP_NS_INIT_INO, \

		struct ipc_namespace *:    IPC_NS_INIT_INO,    \

		struct mnt_namespace *:    MNT_NS_INIT_INO,    \

		struct net *:              NET_NS_INIT_INO,    \

		struct pid_namespace *:    PID_NS_INIT_INO,    \

		struct time_namespace *:   TIME_NS_INIT_INO,   \

		struct user_namespace *:   USER_NS_INIT_INO,   \

		struct uts_namespace *:    UTS_NS_INIT_INO)



#define ns_init_ns(__ns)                                    \

	_Generic((__ns),                                    \

		struct cgroup_namespace *: &init_cgroup_ns, \

		struct ipc_namespace *:    &init_ipc_ns,    \

		struct mnt_namespace *:    &init_mnt_ns,     \

		struct net *:              &init_net,       \

		struct pid_namespace *:    &init_pid_ns,    \

		struct time_namespace *:   &init_time_ns,   \

		struct user_namespace *:   &init_user_ns,   \

		struct uts_namespace *:    &init_uts_ns)



#define ns_init_id(__ns)						\

	_Generic((__ns),						\

		struct cgroup_namespace *:	CGROUP_NS_INIT_ID,	\

		struct ipc_namespace *:		IPC_NS_INIT_ID,		\

		struct mnt_namespace *:		MNT_NS_INIT_ID,		\

		struct net *:			NET_NS_INIT_ID,		\

		struct pid_namespace *:		PID_NS_INIT_ID,		\

		struct time_namespace *:	TIME_NS_INIT_ID,	\

		struct user_namespace *:	USER_NS_INIT_ID,	\

		struct uts_namespace *:		UTS_NS_INIT_ID)



#define to_ns_operations(__ns)                                                                         \

	_Generic((__ns),                                                                               \

		struct cgroup_namespace *: (IS_ENABLED(CONFIG_CGROUPS) ? &cgroupns_operations : NULL), \

		struct ipc_namespace *:    (IS_ENABLED(CONFIG_IPC_NS)  ? &ipcns_operations    : NULL), \

		struct mnt_namespace *:    &mntns_operations,                                          \

		struct net *:              (IS_ENABLED(CONFIG_NET_NS)  ? &netns_operations    : NULL), \

		struct pid_namespace *:    (IS_ENABLED(CONFIG_PID_NS)  ? &pidns_operations    : NULL), \

		struct time_namespace *:   (IS_ENABLED(CONFIG_TIME_NS) ? &timens_operations   : NULL), \

		struct user_namespace *:   (IS_ENABLED(CONFIG_USER_NS) ? &userns_operations   : NULL), \

		struct uts_namespace *:    (IS_ENABLED(CONFIG_UTS_NS)  ? &utsns_operations    : NULL))



#define ns_common_type(__ns)                                \

	_Generic((__ns),                                    \

		struct cgroup_namespace *: CLONE_NEWCGROUP, \

		struct ipc_namespace *:    CLONE_NEWIPC,    \

		struct mnt_namespace *:    CLONE_NEWNS,     \

		struct net *:              CLONE_NEWNET,    \

		struct pid_namespace *:    CLONE_NEWPID,    \

		struct time_namespace *:   CLONE_NEWTIME,   \

		struct user_namespace *:   CLONE_NEWUSER,   \

		struct uts_namespace *:    CLONE_NEWUTS)



#define NS_COMMON_INIT(nsname, refs)							\

{											\