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