/* * 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); /* * 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); 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); }