linux/ipc/util.h
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   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
  96/* must be called with ids->rw_mutex acquired for writing */
  97int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
  98
  99/* must be called with ids->rw_mutex acquired for reading */
 100int ipc_get_maxid(struct ipc_ids *);
 101
 102/* must be called with both locks acquired. */
 103void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
 104
 105/* must be called with ipcp locked */
 106int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
 107
 108/* for rare, potentially huge allocations.
 109 * both function can sleep
 110 */
 111void* ipc_alloc(int size);
 112void ipc_free(void* ptr, int size);
 113
 114/*
 115 * For allocation that need to be freed by RCU.
 116 * Objects are reference counted, they start with reference count 1.
 117 * getref increases the refcount, the putref call that reduces the recount
 118 * to 0 schedules the rcu destruction. Caller must guarantee locking.
 119 */
 120void* ipc_rcu_alloc(int size);
 121void ipc_rcu_getref(void *ptr);
 122void ipc_rcu_putref(void *ptr);
 123
 124struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
 125
 126void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
 127void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
 128int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
 129struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
 130                                      struct ipc_ids *ids, int id, int cmd,
 131                                      struct ipc64_perm *perm, int extra_perm);
 132
 133#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
 134  /* On IA-64, we always use the "64-bit version" of the IPC structures.  */ 
 135# define ipc_parse_version(cmd) IPC_64
 136#else
 137int ipc_parse_version (int *cmd);
 138#endif
 139
 140extern void free_msg(struct msg_msg *msg);
 141extern struct msg_msg *load_msg(const void __user *src, int len);
 142extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
 143
 144extern void recompute_msgmni(struct ipc_namespace *);
 145
 146static inline int ipc_buildid(int id, int seq)
 147{
 148        return SEQ_MULTIPLIER * seq + id;
 149}
 150
 151/*
 152 * Must be called with ipcp locked
 153 */
 154static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
 155{
 156        if (uid / SEQ_MULTIPLIER != ipcp->seq)
 157                return 1;
 158        return 0;
 159}
 160
 161static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
 162{
 163        rcu_read_lock();
 164        spin_lock(&perm->lock);
 165}
 166
 167static inline void ipc_unlock(struct kern_ipc_perm *perm)
 168{
 169        spin_unlock(&perm->lock);
 170        rcu_read_unlock();
 171}
 172
 173struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
 174int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
 175                        struct ipc_ops *ops, struct ipc_params *params);
 176void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
 177                void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
 178#endif
 179
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