| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef _LINUX_NSPROXY_H |
| #define _LINUX_NSPROXY_H |
| |
| #include <linux/spinlock.h> |
| #include <linux/sched.h> |
| |
| struct mnt_namespace; |
| struct uts_namespace; |
| struct ipc_namespace; |
| struct pid_namespace; |
| struct cgroup_namespace; |
| struct fs_struct; |
| |
| /* |
| * A structure to contain pointers to all per-process |
| * namespaces - fs (mount), uts, network, sysvipc, etc. |
| * |
| * The pid namespace is an exception -- it's accessed using |
| * task_active_pid_ns. The pid namespace here is the |
| * namespace that children will use. |
| * |
| * 'count' is the number of tasks holding a reference. |
| * The count for each namespace, then, will be the number |
| * of nsproxies pointing to it, not the number of tasks. |
| * |
| * The nsproxy is shared by tasks which share all namespaces. |
| * As soon as a single namespace is cloned or unshared, the |
| * nsproxy is copied. |
| */ |
| struct nsproxy { |
| atomic_t count; |
| struct uts_namespace *uts_ns; |
| struct ipc_namespace *ipc_ns; |
| struct mnt_namespace *mnt_ns; |
| struct pid_namespace *pid_ns_for_children; |
| struct net *net_ns; |
| struct time_namespace *time_ns; |
| struct time_namespace *time_ns_for_children; |
| struct cgroup_namespace *cgroup_ns; |
| }; |
| extern struct nsproxy init_nsproxy; |
| |
| /* |
| * A structure to encompass all bits needed to install |
| * a partial or complete new set of namespaces. |
| * |
| * If a new user namespace is requested cred will |
| * point to a modifiable set of credentials. If a pointer |
| * to a modifiable set is needed nsset_cred() must be |
| * used and tested. |
| */ |
| struct nsset { |
| unsigned flags; |
| struct nsproxy *nsproxy; |
| struct fs_struct *fs; |
| const struct cred *cred; |
| }; |
| |
| static inline struct cred *nsset_cred(struct nsset *set) |
| { |
| if (set->flags & CLONE_NEWUSER) |
| return (struct cred *)set->cred; |
| |
| return NULL; |
| } |
| |
| /* |
| * the namespaces access rules are: |
| * |
| * 1. only current task is allowed to change tsk->nsproxy pointer or |
| * any pointer on the nsproxy itself. Current must hold the task_lock |
| * when changing tsk->nsproxy. |
| * |
| * 2. when accessing (i.e. reading) current task's namespaces - no |
| * precautions should be taken - just dereference the pointers |
| * |
| * 3. the access to other task namespaces is performed like this |
| * task_lock(task); |
| * nsproxy = task->nsproxy; |
| * if (nsproxy != NULL) { |
| * / * |
| * * work with the namespaces here |
| * * e.g. get the reference on one of them |
| * * / |
| * } / * |
| * * NULL task->nsproxy means that this task is |
| * * almost dead (zombie) |
| * * / |
| * task_unlock(task); |
| * |
| */ |
| |
| int copy_namespaces(unsigned long flags, struct task_struct *tsk); |
| void exit_task_namespaces(struct task_struct *tsk); |
| void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new); |
| void free_nsproxy(struct nsproxy *ns); |
| int unshare_nsproxy_namespaces(unsigned long, struct nsproxy **, |
| struct cred *, struct fs_struct *); |
| int __init nsproxy_cache_init(void); |
| |
| static inline void put_nsproxy(struct nsproxy *ns) |
| { |
| if (atomic_dec_and_test(&ns->count)) { |
| free_nsproxy(ns); |
| } |
| } |
| |
| static inline void get_nsproxy(struct nsproxy *ns) |
| { |
| atomic_inc(&ns->count); |
| } |
| |
| #endif |