LXR linux/ipc/util.h

   1/*
   2 * linux/ipc/util.h
   3 * Copyright (C) 1999 Christoph Rohland
   4 *
   5 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
   6 * namespaces support.      2006 OpenVZ, SWsoft Inc.
   7 *                               Pavel Emelianov <xemul@openvz.org>
   8 */
   9
  10#ifndef _IPC_UTIL_H
  11#define _IPC_UTIL_H
  12
  13#include <linux/unistd.h>
  14#include <linux/err.h>
  15
  16#define SEQ_MULTIPLIER  (IPCMNI)
  17
  18void sem_init (void);
  19void msg_init (void);
  20void shm_init (void);
  21
  22struct ipc_namespace;
  23
  24#ifdef CONFIG_POSIX_MQUEUE
  25extern void mq_clear_sbinfo(struct ipc_namespace *ns);
  26extern void mq_put_mnt(struct ipc_namespace *ns);
  27#else
  28static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
  29static inline void mq_put_mnt(struct ipc_namespace *ns) { }
  30#endif
  31
  32#ifdef CONFIG_SYSVIPC
  33void sem_init_ns(struct ipc_namespace *ns);
  34void msg_init_ns(struct ipc_namespace *ns);
  35void shm_init_ns(struct ipc_namespace *ns);
  36
  37void sem_exit_ns(struct ipc_namespace *ns);
  38void msg_exit_ns(struct ipc_namespace *ns);
  39void shm_exit_ns(struct ipc_namespace *ns);
  40#else
  41static inline void sem_init_ns(struct ipc_namespace *ns) { }
  42static inline void msg_init_ns(struct ipc_namespace *ns) { }
  43static inline void shm_init_ns(struct ipc_namespace *ns) { }
  44
  45static inline void sem_exit_ns(struct ipc_namespace *ns) { }
  46static inline void msg_exit_ns(struct ipc_namespace *ns) { }
  47static inline void shm_exit_ns(struct ipc_namespace *ns) { }
  48#endif
  49
  50/*
  51 * Structure that holds the parameters needed by the ipc operations
  52 * (see after)
  53 */
  54struct ipc_params {
  55        key_t key;
  56        int flg;
  57        union {
  58                size_t size;    /* for shared memories */
  59                int nsems;      /* for semaphores */
  60        } u;                    /* holds the getnew() specific param */
  61};
  62
  63/*
  64 * Structure that holds some ipc operations. This structure is used to unify
  65 * the calls to sys_msgget(), sys_semget(), sys_shmget()
  66 *      . routine to call to create a new ipc object. Can be one of newque,
  67 *        newary, newseg
  68 *      . routine to call to check permissions for a new ipc object.
  69 *        Can be one of security_msg_associate, security_sem_associate,
  70 *        security_shm_associate
  71 *      . routine to call for an extra check if needed
  72 */
  73struct ipc_ops {
  74        int (*getnew) (struct ipc_namespace *, struct ipc_params *);
  75        int (*associate) (struct kern_ipc_perm *, int);
  76        int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
  77};
  78
  79struct seq_file;
  80struct ipc_ids;
  81
  82void ipc_init_ids(struct ipc_ids *);
  83#ifdef CONFIG_PROC_FS
  84void __init ipc_init_proc_interface(const char *path, const char *header,
  85                int ids, int (*show)(struct seq_file *, void *));
  86#else
  87#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
  88#endif
  89
  90#define IPC_SEM_IDS     0
  91#define IPC_MSG_IDS     1
  92#define IPC_SHM_IDS     2
  93
  94#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
  95#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
  96
  97/* must be called with ids->rw_mutex acquired for writing */
  98int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
  99
 100/* must be called with ids->rw_mutex acquired for reading */
 101int ipc_get_maxid(struct ipc_ids *);
 102
 103/* must be called with both locks acquired. */
 104void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
 105
 106/* must be called with ipcp locked */
 107int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
 108
 109/* for rare, potentially huge allocations.
 110 * both function can sleep
 111 */
 112void* ipc_alloc(int size);
 113void ipc_free(void* ptr, int size);
 114
 115/*
 116 * For allocation that need to be freed by RCU.
 117 * Objects are reference counted, they start with reference count 1.
 118 * getref increases the refcount, the putref call that reduces the recount
 119 * to 0 schedules the rcu destruction. Caller must guarantee locking.
 120 */
 121void* ipc_rcu_alloc(int size);
 122int ipc_rcu_getref(void *ptr);
 123void ipc_rcu_putref(void *ptr);
 124
 125struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
 126struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id);
 127
 128void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
 129void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
 130int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
 131struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
 132                                             struct ipc_ids *ids, int id, int cmd,
 133                                             struct ipc64_perm *perm, int extra_perm);
 134struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
 135                                      struct ipc_ids *ids, int id, int cmd,
 136                                      struct ipc64_perm *perm, int extra_perm);
 137
 138#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
 139  /* On IA-64, we always use the "64-bit version" of the IPC structures.  */ 
 140# define ipc_parse_version(cmd) IPC_64
 141#else
 142int ipc_parse_version (int *cmd);
 143#endif
 144
 145extern void free_msg(struct msg_msg *msg);
 146extern struct msg_msg *load_msg(const void __user *src, int len);
 147extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
 148extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
 149
 150extern void recompute_msgmni(struct ipc_namespace *);
 151
 152static inline int ipc_buildid(int id, int seq)
 153{
 154        return SEQ_MULTIPLIER * seq + id;
 155}
 156
 157static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
 158{
 159        return uid / SEQ_MULTIPLIER != ipcp->seq;
 160}
 161
 162static inline void ipc_lock_object(struct kern_ipc_perm *perm)
 163{
 164        spin_lock(&perm->lock);
 165}
 166
 167static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
 168{
 169        spin_unlock(&perm->lock);
 170}
 171
 172static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
 173{
 174        assert_spin_locked(&perm->lock);
 175}
 176
 177static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
 178{
 179        rcu_read_lock();
 180        ipc_lock_object(perm);
 181}
 182
 183static inline void ipc_unlock(struct kern_ipc_perm *perm)
 184{
 185        ipc_unlock_object(perm);
 186        rcu_read_unlock();
 187}
 188
 189struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
 190struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
 191int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
 192                        struct ipc_ops *ops, struct ipc_params *params);
 193void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
 194                void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
 195#endif
 196