ipc_namespace.h

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#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;
    unsigned short seq_max;
    struct rw_semaphore rw_mutex;
    struct idr ipcs_idr;
};

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

    int     sem_ctls[4];
    int     used_sems;

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

    size_t      shm_ctlmax;
    size_t      shm_ctlall;
    int     shm_ctlmni;
    int     shm_tot;
    /*
     * 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;
};

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 MIN_QUEUESMAX           1
#define DFLT_QUEUESMAX            256
#define HARD_QUEUESMAX           1024
#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 task_struct *tsk);
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 task_struct *tsk)
{
    if (flags & CLONE_NEWIPC)
        return ERR_PTR(-EINVAL);

    return tsk->nsproxy->ipc_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