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Each pid namespace have to be visible through its own proc mount. Thus we need to have per-namespace proc trees with their own superblocks. We cannot easily show different pid namespace via one global proc tree, since each pid refers to different tasks in different namespaces. E.g. pid 1 refers to the init task in the initial namespace and to some other task when seeing from another namespace. Moreover - pid, exisintg in one namespace may not exist in the other. This approach has one move advantage is that the tasks from the init namespace can see what tasks live in another namespace by reading entries from another proc tree. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Paul Menage <menage@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
57 lines
1.2 KiB
C
57 lines
1.2 KiB
C
#ifndef _LINUX_PID_NS_H
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#define _LINUX_PID_NS_H
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/threads.h>
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#include <linux/pid.h>
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#include <linux/nsproxy.h>
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#include <linux/kref.h>
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struct pidmap {
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atomic_t nr_free;
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void *page;
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};
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#define PIDMAP_ENTRIES ((PID_MAX_LIMIT + 8*PAGE_SIZE - 1)/PAGE_SIZE/8)
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struct pid_namespace {
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struct kref kref;
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struct pidmap pidmap[PIDMAP_ENTRIES];
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int last_pid;
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struct task_struct *child_reaper;
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struct kmem_cache *pid_cachep;
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int level;
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struct pid_namespace *parent;
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#ifdef CONFIG_PROC_FS
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struct vfsmount *proc_mnt;
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#endif
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};
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extern struct pid_namespace init_pid_ns;
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static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
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{
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kref_get(&ns->kref);
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return ns;
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}
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extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *ns);
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extern void free_pid_ns(struct kref *kref);
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static inline void put_pid_ns(struct pid_namespace *ns)
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{
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kref_put(&ns->kref, free_pid_ns);
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}
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static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
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{
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return tsk->nsproxy->pid_ns;
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}
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static inline struct task_struct *task_child_reaper(struct task_struct *tsk)
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{
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return init_pid_ns.child_reaper;
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}
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#endif /* _LINUX_PID_NS_H */
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