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 176