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b34a6b1da3
Add support for the shm_rmid_forced sysctl. If set to 1, all shared memory objects in current ipc namespace will be automatically forced to use IPC_RMID. The POSIX way of handling shmem allows one to create shm objects and call shmdt(), leaving shm object associated with no process, thus consuming memory not counted via rlimits. With shm_rmid_forced=1 the shared memory object is counted at least for one process, so OOM killer may effectively kill the fat process holding the shared memory. It obviously breaks POSIX - some programs relying on the feature would stop working. So set shm_rmid_forced=1 only if you're sure nobody uses "orphaned" memory. Use shm_rmid_forced=0 by default for compatability reasons. The feature was previously impemented in -ow as a configure option. [akpm@linux-foundation.org: fix documentation, per Randy] [akpm@linux-foundation.org: fix warning] [akpm@linux-foundation.org: readability/conventionality tweaks] [akpm@linux-foundation.org: fix shm_rmid_forced/shm_forced_rmid confusion, use standard comment layout] Signed-off-by: Vasiliy Kulikov <segoon@openwall.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Serge E. Hallyn" <serge.hallyn@canonical.com> Cc: Daniel Lezcano <daniel.lezcano@free.fr> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Solar Designer <solar@openwall.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
147 lines
3.7 KiB
C
147 lines
3.7 KiB
C
#ifndef __IPC_NAMESPACE_H__
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#define __IPC_NAMESPACE_H__
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#include <linux/err.h>
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#include <linux/idr.h>
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#include <linux/rwsem.h>
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#include <linux/notifier.h>
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#include <linux/nsproxy.h>
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/*
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* ipc namespace events
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*/
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#define IPCNS_MEMCHANGED 0x00000001 /* Notify lowmem size changed */
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#define IPCNS_CREATED 0x00000002 /* Notify new ipc namespace created */
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#define IPCNS_REMOVED 0x00000003 /* Notify ipc namespace removed */
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#define IPCNS_CALLBACK_PRI 0
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struct user_namespace;
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struct ipc_ids {
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int in_use;
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unsigned short seq;
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unsigned short seq_max;
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struct rw_semaphore rw_mutex;
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struct idr ipcs_idr;
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};
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struct ipc_namespace {
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atomic_t count;
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struct ipc_ids ids[3];
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int sem_ctls[4];
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int used_sems;
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int msg_ctlmax;
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int msg_ctlmnb;
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int msg_ctlmni;
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atomic_t msg_bytes;
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atomic_t msg_hdrs;
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int auto_msgmni;
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size_t shm_ctlmax;
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size_t shm_ctlall;
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int shm_ctlmni;
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int shm_tot;
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/*
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* Defines whether IPC_RMID is forced for _all_ shm segments regardless
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* of shmctl()
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*/
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int shm_rmid_forced;
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struct notifier_block ipcns_nb;
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/* The kern_mount of the mqueuefs sb. We take a ref on it */
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struct vfsmount *mq_mnt;
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/* # queues in this ns, protected by mq_lock */
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unsigned int mq_queues_count;
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/* next fields are set through sysctl */
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unsigned int mq_queues_max; /* initialized to DFLT_QUEUESMAX */
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unsigned int mq_msg_max; /* initialized to DFLT_MSGMAX */
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unsigned int mq_msgsize_max; /* initialized to DFLT_MSGSIZEMAX */
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/* user_ns which owns the ipc ns */
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struct user_namespace *user_ns;
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};
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extern struct ipc_namespace init_ipc_ns;
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extern atomic_t nr_ipc_ns;
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extern spinlock_t mq_lock;
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#ifdef CONFIG_SYSVIPC
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extern int register_ipcns_notifier(struct ipc_namespace *);
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extern int cond_register_ipcns_notifier(struct ipc_namespace *);
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extern void unregister_ipcns_notifier(struct ipc_namespace *);
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extern int ipcns_notify(unsigned long);
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extern void shm_destroy_orphaned(struct ipc_namespace *ns);
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#else /* CONFIG_SYSVIPC */
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static inline int register_ipcns_notifier(struct ipc_namespace *ns)
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{ return 0; }
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static inline int cond_register_ipcns_notifier(struct ipc_namespace *ns)
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{ return 0; }
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static inline void unregister_ipcns_notifier(struct ipc_namespace *ns) { }
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static inline int ipcns_notify(unsigned long l) { return 0; }
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static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
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#endif /* CONFIG_SYSVIPC */
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#ifdef CONFIG_POSIX_MQUEUE
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extern int mq_init_ns(struct ipc_namespace *ns);
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/* default values */
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#define DFLT_QUEUESMAX 256 /* max number of message queues */
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#define DFLT_MSGMAX 10 /* max number of messages in each queue */
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#define HARD_MSGMAX (32768*sizeof(void *)/4)
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#define DFLT_MSGSIZEMAX 8192 /* max message size */
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#else
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static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
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#endif
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#if defined(CONFIG_IPC_NS)
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extern struct ipc_namespace *copy_ipcs(unsigned long flags,
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struct task_struct *tsk);
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static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
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{
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if (ns)
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atomic_inc(&ns->count);
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return ns;
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}
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extern void put_ipc_ns(struct ipc_namespace *ns);
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#else
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static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
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struct task_struct *tsk)
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{
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if (flags & CLONE_NEWIPC)
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return ERR_PTR(-EINVAL);
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return tsk->nsproxy->ipc_ns;
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}
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static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
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{
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return ns;
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}
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static inline void put_ipc_ns(struct ipc_namespace *ns)
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{
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}
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#endif
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#ifdef CONFIG_POSIX_MQUEUE_SYSCTL
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struct ctl_table_header;
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extern struct ctl_table_header *mq_register_sysctl_table(void);
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#else /* CONFIG_POSIX_MQUEUE_SYSCTL */
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static inline struct ctl_table_header *mq_register_sysctl_table(void)
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{
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return NULL;
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}
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#endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
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#endif
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