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/*
* linux/ipc/namespace.c
* Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
*/
#include <linux/ipc.h>
#include <linux/msg.h>
#include <linux/ipc_namespace.h>
#include <linux/rcupdate.h>
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include "util.h"
static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
{
struct ipc_namespace *ns;
ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
if (ns == NULL)
return ERR_PTR(-ENOMEM);
atomic_inc(&nr_ipc_ns);
sem_init_ns(ns);
msg_init_ns(ns);
shm_init_ns(ns);
mq_init_ns(ns);
/*
* msgmni has already been computed for the new ipc ns.
* Thus, do the ipcns creation notification before registering that
* new ipcns in the chain.
*/
ipcns_notify(IPCNS_CREATED);
register_ipcns_notifier(ns);
kref_init(&ns->kref);
return ns;
}
struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
{
struct ipc_namespace *new_ns;
BUG_ON(!ns);
get_ipc_ns(ns);
if (!(flags & CLONE_NEWIPC))
return ns;
new_ns = clone_ipc_ns(ns);
put_ipc_ns(ns);
return new_ns;
}
/*
* free_ipcs - free all ipcs of one type
* @ns: the namespace to remove the ipcs from
* @ids: the table of ipcs to free
* @free: the function called to free each individual ipc
*
* Called for each kind of ipc when an ipc_namespace exits.
*/
void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
{
struct kern_ipc_perm *perm;
int next_id;
int total, in_use;
down_write(&ids->rw_mutex);
in_use = ids->in_use;
for (total = 0, next_id = 0; total < in_use; next_id++) {
perm = idr_find(&ids->ipcs_idr, next_id);
if (perm == NULL)
continue;
ipc_lock_by_ptr(perm);
free(ns, perm);
total++;
}
up_write(&ids->rw_mutex);
}
void free_ipc_ns(struct kref *kref)
{
struct ipc_namespace *ns;
ns = container_of(kref, struct ipc_namespace, kref);
/*
* Unregistering the hotplug notifier at the beginning guarantees
* that the ipc namespace won't be freed while we are inside the
* callback routine. Since the blocking_notifier_chain_XXX routines
* hold a rw lock on the notifier list, unregister_ipcns_notifier()
* won't take the rw lock before blocking_notifier_call_chain() has
* released the rd lock.
*/
unregister_ipcns_notifier(ns);
sem_exit_ns(ns);
msg_exit_ns(ns);
shm_exit_ns(ns);
mq_exit_ns(ns);
kfree(ns);
atomic_dec(&nr_ipc_ns);
/*
* Do the ipcns removal notification after decrementing nr_ipc_ns in
* order to have a correct value when recomputing msgmni.
*/
ipcns_notify(IPCNS_REMOVED);
}
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