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/err.h>
  14
  15 #define SEQ_MULTIPLIER  (IPCMNI)
  16
  17 void sem_init (void);
  18 void msg_init (void);
  19 void shm_init (void);
  20
  21 struct ipc_namespace;
  22
  23 #ifdef CONFIG_POSIX_MQUEUE
  24 extern void mq_clear_sbinfo(struct ipc_namespace *ns);
  25 extern void mq_put_mnt(struct ipc_namespace *ns);
  26 #else
  27 static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
  28 static inline void mq_put_mnt(struct ipc_namespace *ns) { }
  29 #endif
  30
  31 #ifdef CONFIG_SYSVIPC
  32 void sem_init_ns(struct ipc_namespace *ns);
  33 void msg_init_ns(struct ipc_namespace *ns);
  34 void shm_init_ns(struct ipc_namespace *ns);
  35
  36 void sem_exit_ns(struct ipc_namespace *ns);
  37 void msg_exit_ns(struct ipc_namespace *ns);
  38 void shm_exit_ns(struct ipc_namespace *ns);
  39 #else
  40 static inline void sem_init_ns(struct ipc_namespace *ns) { }
  41 static inline void msg_init_ns(struct ipc_namespace *ns) { }
  42 static inline void shm_init_ns(struct ipc_namespace *ns) { }
  43
  44 static inline void sem_exit_ns(struct ipc_namespace *ns) { }
  45 static inline void msg_exit_ns(struct ipc_namespace *ns) { }
  46 static inline void shm_exit_ns(struct ipc_namespace *ns) { }
  47 #endif
  48
  49 /*
  50  * Structure that holds the parameters needed by the ipc operations
  51  * (see after)
  52  */
  53 struct ipc_params {
  54         key_t key;
  55         int flg;
  56         union {
  57                 size_t size;    /* for shared memories */
  58                 int nsems;      /* for semaphores */
  59         } u;                    /* holds the getnew() specific param */
  60 };
  61
  62 /*
  63  * Structure that holds some ipc operations. This structure is used to unify
  64  * the calls to sys_msgget(), sys_semget(), sys_shmget()
  65  *      . routine to call to create a new ipc object. Can be one of newque,
  66  *        newary, newseg
  67  *      . routine to call to check permissions for a new ipc object.
  68  *        Can be one of security_msg_associate, security_sem_associate,
  69  *        security_shm_associate
  70  *      . routine to call for an extra check if needed
  71  */
  72 struct ipc_ops {
  73         int (*getnew) (struct ipc_namespace *, struct ipc_params *);
  74         int (*associate) (struct kern_ipc_perm *, int);
  75         int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
  76 };
  77
  78 struct seq_file;
  79 struct ipc_ids;
  80
  81 void ipc_init_ids(struct ipc_ids *);
  82 #ifdef CONFIG_PROC_FS
  83 void __init ipc_init_proc_interface(const char *path, const char *header,
  84                 int ids, int (*show)(struct seq_file *, void *));
  85 #else
  86 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
  87 #endif
  88
  89 #define IPC_SEM_IDS     0
  90 #define IPC_MSG_IDS     1
  91 #define IPC_SHM_IDS     2
  92
  93 #define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
  94
  95 /* must be called with ids->rw_mutex acquired for writing */
  96 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
  97
  98 /* must be called with ids->rw_mutex acquired for reading */
  99 int ipc_get_maxid(struct ipc_ids *);
 100
 101 /* must be called with both locks acquired. */
 102 void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
 103
 104 /* must be called with ipcp locked */
 105 int ipcperms(struct kern_ipc_perm *ipcp, short flg);
 106
 107 /* for rare, potentially huge allocations.
 108  * both function can sleep
 109  */
 110 void* ipc_alloc(int size);
 111 void ipc_free(void* ptr, int size);
 112
 113 /*
 114  * For allocation that need to be freed by RCU.
 115  * Objects are reference counted, they start with reference count 1.
 116  * getref increases the refcount, the putref call that reduces the recount
 117  * to 0 schedules the rcu destruction. Caller must guarantee locking.
 118  */
 119 void* ipc_rcu_alloc(int size);
 120 void ipc_rcu_getref(void *ptr);
 121 void ipc_rcu_putref(void *ptr);
 122
 123 struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
 124
 125 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
 126 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
 127 void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
 128 struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
 129                                       struct ipc64_perm *perm, int extra_perm);
 130
 131 #if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__) || defined(__XTENSA__)
 132   /* On IA-64, we always use the "64-bit version" of the IPC structures.  */
 133 # define ipc_parse_version(cmd) IPC_64
 134 #else
 135 int ipc_parse_version (int *cmd);
 136 #endif
 137
 138 extern void free_msg(struct msg_msg *msg);
 139 extern struct msg_msg *load_msg(const void __user *src, int len);
 140 extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
 141
 142 extern void recompute_msgmni(struct ipc_namespace *);
 143
 144 static inline int ipc_buildid(int id, int seq)
 145 {
 146         return SEQ_MULTIPLIER * seq + id;
 147 }
 148
 149 /*
 150  * Must be called with ipcp locked
 151  */
 152 static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
 153 {
 154         if (uid / SEQ_MULTIPLIER != ipcp->seq)
 155                 return 1;
 156         return 0;
 157 }
 158
 159 static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
 160 {
 161         rcu_read_lock();
 162         spin_lock(&perm->lock);
 163 }
 164
 165 static inline void ipc_unlock(struct kern_ipc_perm *perm)
 166 {
 167         spin_unlock(&perm->lock);
 168         rcu_read_unlock();
 169 }
 170
 171 struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
 172 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
 173                         struct ipc_ops *ops, struct ipc_params *params);
 174
 175 #endif