root/include/linux/ipc_namespace.h

DEFINITIONS

1. register_ipcns_notifier
2. cond_register_ipcns_notifier
3. unregister_ipcns_notifier
4. ipcns_notify
5. shm_destroy_orphaned
6. mq_init_ns
7. get_ipc_ns
8. copy_ipcs
9. get_ipc_ns
10. put_ipc_ns
11. mq_register_sysctl_table

#ifndef __IPC_NAMESPACE_H__
#define __IPC_NAMESPACE_H__

#include <linux/err.h>
#include <linux/idr.h>
#include <linux/rwsem.h>
#include <linux/notifier.h>
#include <linux/nsproxy.h>

/*
 * ipc namespace events
 */
#define IPCNS_MEMCHANGED   0x00000001   /* Notify lowmem size changed */
#define IPCNS_CREATED  0x00000002   /* Notify new ipc namespace created */
#define IPCNS_REMOVED  0x00000003   /* Notify ipc namespace removed */

#define IPCNS_CALLBACK_PRI 0

struct user_namespace;

struct ipc_ids {
        int in_use;
        unsigned short seq;
        struct rw_semaphore rwsem;
        struct idr ipcs_idr;
        int next_id;
};

struct ipc_namespace {
        atomic_t        count;
        struct ipc_ids  ids[3];

        int             sem_ctls[4];
        int             used_sems;

        unsigned int    msg_ctlmax;
        unsigned int    msg_ctlmnb;
        unsigned int    msg_ctlmni;
        atomic_t        msg_bytes;
        atomic_t        msg_hdrs;
        int             auto_msgmni;

        size_t          shm_ctlmax;
        size_t          shm_ctlall;
        unsigned long   shm_tot;
        int             shm_ctlmni;
        /*
         * Defines whether IPC_RMID is forced for _all_ shm segments regardless
         * of shmctl()
         */
        int             shm_rmid_forced;

        struct notifier_block ipcns_nb;

        /* The kern_mount of the mqueuefs sb.  We take a ref on it */
        struct vfsmount *mq_mnt;

        /* # queues in this ns, protected by mq_lock */
        unsigned int    mq_queues_count;

        /* next fields are set through sysctl */
        unsigned int    mq_queues_max;   /* initialized to DFLT_QUEUESMAX */
        unsigned int    mq_msg_max;      /* initialized to DFLT_MSGMAX */
        unsigned int    mq_msgsize_max;  /* initialized to DFLT_MSGSIZEMAX */
        unsigned int    mq_msg_default;
        unsigned int    mq_msgsize_default;

        /* user_ns which owns the ipc ns */
        struct user_namespace *user_ns;

        unsigned int    proc_inum;
};

extern struct ipc_namespace init_ipc_ns;
extern atomic_t nr_ipc_ns;

extern spinlock_t mq_lock;

#ifdef CONFIG_SYSVIPC
extern int register_ipcns_notifier(struct ipc_namespace *);
extern int cond_register_ipcns_notifier(struct ipc_namespace *);
extern void unregister_ipcns_notifier(struct ipc_namespace *);
extern int ipcns_notify(unsigned long);
extern void shm_destroy_orphaned(struct ipc_namespace *ns);
#else /* CONFIG_SYSVIPC */
static inline int register_ipcns_notifier(struct ipc_namespace *ns)
{ return 0; }
static inline int cond_register_ipcns_notifier(struct ipc_namespace *ns)
{ return 0; }
static inline void unregister_ipcns_notifier(struct ipc_namespace *ns) { }
static inline int ipcns_notify(unsigned long l) { return 0; }
static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
#endif /* CONFIG_SYSVIPC */

#ifdef CONFIG_POSIX_MQUEUE
extern int mq_init_ns(struct ipc_namespace *ns);
/*
 * POSIX Message Queue default values:
 *
 * MIN_*: Lowest value an admin can set the maximum unprivileged limit to
 * DFLT_*MAX: Default values for the maximum unprivileged limits
 * DFLT_{MSG,MSGSIZE}: Default values used when the user doesn't supply
 *   an attribute to the open call and the queue must be created
 * HARD_*: Highest value the maximums can be set to.  These are enforced
 *   on CAP_SYS_RESOURCE apps as well making them inviolate (so make them
 *   suitably high)
 *
 * POSIX Requirements:
 *   Per app minimum openable message queues - 8.  This does not map well
 *     to the fact that we limit the number of queues on a per namespace
 *     basis instead of a per app basis.  So, make the default high enough
 *     that no given app should have a hard time opening 8 queues.
 *   Minimum maximum for HARD_MSGMAX - 32767.  I bumped this to 65536.
 *   Minimum maximum for HARD_MSGSIZEMAX - POSIX is silent on this.  However,
 *     we have run into a situation where running applications in the wild
 *     require this to be at least 5MB, and preferably 10MB, so I set the
 *     value to 16MB in hopes that this user is the worst of the bunch and
 *     the new maximum will handle anyone else.  I may have to revisit this
 *     in the future.
 */
#define DFLT_QUEUESMAX                256
#define MIN_MSGMAX                      1
#define DFLT_MSG                       10U
#define DFLT_MSGMAX                    10
#define HARD_MSGMAX                 65536
#define MIN_MSGSIZEMAX                128
#define DFLT_MSGSIZE                 8192U
#define DFLT_MSGSIZEMAX              8192
#define HARD_MSGSIZEMAX     (16*1024*1024)
#else
static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
#endif

#if defined(CONFIG_IPC_NS)
extern struct ipc_namespace *copy_ipcs(unsigned long flags,
        struct user_namespace *user_ns, struct ipc_namespace *ns);

static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
{
        if (ns)
                atomic_inc(&ns->count);
        return ns;
}

extern void put_ipc_ns(struct ipc_namespace *ns);
#else
static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
        struct user_namespace *user_ns, struct ipc_namespace *ns)
{
        if (flags & CLONE_NEWIPC)
                return ERR_PTR(-EINVAL);

        return ns;
}

static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
{
        return ns;
}

static inline void put_ipc_ns(struct ipc_namespace *ns)
{
}
#endif

#ifdef CONFIG_POSIX_MQUEUE_SYSCTL

struct ctl_table_header;
extern struct ctl_table_header *mq_register_sysctl_table(void);

#else /* CONFIG_POSIX_MQUEUE_SYSCTL */

static inline struct ctl_table_header *mq_register_sysctl_table(void)
{
        return NULL;
}

#endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
#endif