cregit-Linux how code gets into the kernel

Release 4.12 include/linux/nsproxy.h

Directory: include/linux


#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 cgroup_namespace *cgroup_ns;
extern struct nsproxy init_nsproxy;

 * 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); } }


Serge E. Hallyn2275.86%150.00%
Linus Torvalds724.14%150.00%

static inline void get_nsproxy(struct nsproxy *ns) { atomic_inc(&ns->count); }


Serge E. Hallyn1050.00%133.33%
Pavel Emelyanov630.00%133.33%
Vasily Tarasov420.00%133.33%


Overall Contributors

Serge E. Hallyn10050.51%316.67%
Pavel Emelyanov2110.61%15.56%
Badari Pulavarty168.08%15.56%
Eric W. Biedermann126.06%422.22%
Kirill Korotaev115.56%211.11%
Al Viro105.05%211.11%
Aditya Kali84.04%15.56%
Cédric Le Goater73.54%15.56%
Linus Torvalds73.54%15.56%
Vasily Tarasov42.02%15.56%
Andrew Lutomirski21.01%15.56%
Directory: include/linux
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