/* SPDX-License-Identifier: GPL-2.0 */
#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>
#include <linux/ns_common.h>
#include <linux/refcount.h>
#include <linux/rhashtable-types.h>
#include <linux/sysctl.h>
#include <linux/percpu_counter.h>

struct user_namespace;

struct ipc_ids {
        int in_use;
        unsigned short seq;
        struct rw_semaphore rwsem;
        struct idr ipcs_idr;
        int max_idx;
        int last_idx;   /* For wrap around detection */
#ifdef CONFIG_CHECKPOINT_RESTORE
        int next_id;
#endif
        struct rhashtable key_ht;
};

struct ipc_namespace {
        struct ipc_ids  ids[3];

        int             sem_ctls[4];
        int             used_sems;

        unsigned int    msg_ctlmax;
        unsigned int    msg_ctlmnb;
        unsigned int    msg_ctlmni;
        struct percpu_counter percpu_msg_bytes;
        struct percpu_counter percpu_msg_hdrs;

        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;

        struct ctl_table_set    mq_set;
        struct ctl_table_header *mq_sysctls;

        struct ctl_table_set    ipc_set;
        struct ctl_table_header *ipc_sysctls;

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

        struct llist_node mnt_llist;

        struct ns_common ns;
} __randomize_layout;

extern struct ipc_namespace init_ipc_ns;
extern spinlock_t mq_lock;

#ifdef CONFIG_SYSVIPC
extern void shm_destroy_orphaned(struct ipc_namespace *ns);
#else /* CONFIG_SYSVIPC */
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)
static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
{
        return container_of(ns, struct ipc_namespace, ns);
}

extern struct ipc_namespace *copy_ipcs(u64 flags,
        struct user_namespace *user_ns, struct ipc_namespace *ns);

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

static inline struct ipc_namespace *get_ipc_ns_not_zero(struct ipc_namespace *ns)
{
        if (ns) {
                if (ns_ref_get(ns))
                        return ns;
        }

        return NULL;
}

extern void put_ipc_ns(struct ipc_namespace *ns);
#else
static inline struct ipc_namespace *copy_ipcs(u64 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 struct ipc_namespace *get_ipc_ns_not_zero(struct ipc_namespace *ns)
{
        return ns;
}

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

#ifdef CONFIG_POSIX_MQUEUE_SYSCTL

void retire_mq_sysctls(struct ipc_namespace *ns);
bool setup_mq_sysctls(struct ipc_namespace *ns);

#else /* CONFIG_POSIX_MQUEUE_SYSCTL */

static inline void retire_mq_sysctls(struct ipc_namespace *ns)
{
}

static inline bool setup_mq_sysctls(struct ipc_namespace *ns)
{
        return true;
}

#endif /* CONFIG_POSIX_MQUEUE_SYSCTL */

#ifdef CONFIG_SYSVIPC_SYSCTL

bool setup_ipc_sysctls(struct ipc_namespace *ns);
void retire_ipc_sysctls(struct ipc_namespace *ns);

#else /* CONFIG_SYSVIPC_SYSCTL */

static inline void retire_ipc_sysctls(struct ipc_namespace *ns)
{
}

static inline bool setup_ipc_sysctls(struct ipc_namespace *ns)
{
        return true;
}

#endif /* CONFIG_SYSVIPC_SYSCTL */
#endif