129 lines · c
1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _LINUX_NSPROXY_H3#define _LINUX_NSPROXY_H4 5#include <linux/refcount.h>6#include <linux/spinlock.h>7#include <linux/sched.h>8 9struct mnt_namespace;10struct uts_namespace;11struct ipc_namespace;12struct pid_namespace;13struct cgroup_namespace;14struct fs_struct;15 16/*17 * A structure to contain pointers to all per-process18 * namespaces - fs (mount), uts, network, sysvipc, etc.19 *20 * The pid namespace is an exception -- it's accessed using21 * task_active_pid_ns. The pid namespace here is the22 * namespace that children will use.23 *24 * 'count' is the number of tasks holding a reference.25 * The count for each namespace, then, will be the number26 * of nsproxies pointing to it, not the number of tasks.27 *28 * The nsproxy is shared by tasks which share all namespaces.29 * As soon as a single namespace is cloned or unshared, the30 * nsproxy is copied.31 */32struct nsproxy {33 refcount_t count;34 struct uts_namespace *uts_ns;35 struct ipc_namespace *ipc_ns;36 struct mnt_namespace *mnt_ns;37 struct pid_namespace *pid_ns_for_children;38 struct net *net_ns;39 struct time_namespace *time_ns;40 struct time_namespace *time_ns_for_children;41 struct cgroup_namespace *cgroup_ns;42};43extern struct nsproxy init_nsproxy;44 45#define to_ns_common(__ns) \46 _Generic((__ns), \47 struct cgroup_namespace *: &(__ns->ns), \48 struct ipc_namespace *: &(__ns->ns), \49 struct net *: &(__ns->ns), \50 struct pid_namespace *: &(__ns->ns), \51 struct mnt_namespace *: &(__ns->ns), \52 struct time_namespace *: &(__ns->ns), \53 struct user_namespace *: &(__ns->ns), \54 struct uts_namespace *: &(__ns->ns))55 56/*57 * A structure to encompass all bits needed to install58 * a partial or complete new set of namespaces.59 *60 * If a new user namespace is requested cred will61 * point to a modifiable set of credentials. If a pointer62 * to a modifiable set is needed nsset_cred() must be63 * used and tested.64 */65struct nsset {66 unsigned flags;67 struct nsproxy *nsproxy;68 struct fs_struct *fs;69 const struct cred *cred;70};71 72static inline struct cred *nsset_cred(struct nsset *set)73{74 if (set->flags & CLONE_NEWUSER)75 return (struct cred *)set->cred;76 77 return NULL;78}79 80/*81 * the namespaces access rules are:82 *83 * 1. only current task is allowed to change tsk->nsproxy pointer or84 * any pointer on the nsproxy itself. Current must hold the task_lock85 * when changing tsk->nsproxy.86 *87 * 2. when accessing (i.e. reading) current task's namespaces - no88 * precautions should be taken - just dereference the pointers89 *90 * 3. the access to other task namespaces is performed like this91 * task_lock(task);92 * nsproxy = task->nsproxy;93 * if (nsproxy != NULL) {94 * / *95 * * work with the namespaces here96 * * e.g. get the reference on one of them97 * * /98 * } / *99 * * NULL task->nsproxy means that this task is100 * * almost dead (zombie)101 * * /102 * task_unlock(task);103 *104 */105 106int copy_namespaces(unsigned long flags, struct task_struct *tsk) HWJS_SUSPENDS;107void exit_task_namespaces(struct task_struct *tsk) HWJS_SUSPENDS;108void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new) HWJS_SUSPENDS;109int exec_task_namespaces(void) HWJS_SUSPENDS;110void free_nsproxy(struct nsproxy *ns) HWJS_SUSPENDS;111int unshare_nsproxy_namespaces(unsigned long, struct nsproxy **,112 struct cred *, struct fs_struct *) HWJS_SUSPENDS;113int __init nsproxy_cache_init(void);114 115static inline void put_nsproxy(struct nsproxy *ns)116{117 if (refcount_dec_and_test(&ns->count))118 free_nsproxy(ns);119}120 121static inline void get_nsproxy(struct nsproxy *ns)122{123 refcount_inc(&ns->count);124}125 126DEFINE_FREE(put_nsproxy, struct nsproxy *, if (_T) put_nsproxy(_T))127 128#endif129