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 18 void sem_init (void); 19 void msg_init (void); 20 void shm_init (void); 21 22 struct ipc_namespace; 23 24 #ifdef CONFIG_POSIX_MQUEUE 25 extern void mq_clear_sbinfo(struct ipc_namespace *ns); 26 extern void mq_put_mnt(struct ipc_namespace *ns); 27 #else 28 static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { } 29 static inline void mq_put_mnt(struct ipc_namespace *ns) { } 30 #endif 31 32 #ifdef CONFIG_SYSVIPC 33 void sem_init_ns(struct ipc_namespace *ns); 34 void msg_init_ns(struct ipc_namespace *ns); 35 void shm_init_ns(struct ipc_namespace *ns); 36 37 void sem_exit_ns(struct ipc_namespace *ns); 38 void msg_exit_ns(struct ipc_namespace *ns); 39 void shm_exit_ns(struct ipc_namespace *ns); 40 #else 41 static inline void sem_init_ns(struct ipc_namespace *ns) { } 42 static inline void msg_init_ns(struct ipc_namespace *ns) { } 43 static inline void shm_init_ns(struct ipc_namespace *ns) { } 44 45 static inline void sem_exit_ns(struct ipc_namespace *ns) { } 46 static inline void msg_exit_ns(struct ipc_namespace *ns) { } 47 static 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 */ 54 struct 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 */ 73 struct 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 79 struct seq_file; 80 struct ipc_ids; 81 82 void ipc_init_ids(struct ipc_ids *); 83 #ifdef CONFIG_PROC_FS 84 void __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 */ 98 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); 99 100 /* must be called with ids->rw_mutex acquired for reading */ 101 int ipc_get_maxid(struct ipc_ids *); 102 103 /* must be called with both locks acquired. */ 104 void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); 105 106 /* must be called with ipcp locked */ 107 int 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 */ 112 void* ipc_alloc(int size); 113 void 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 */ 121 void* ipc_rcu_alloc(int size); 122 void ipc_rcu_getref(void *ptr); 123 void ipc_rcu_putref(void *ptr); 124 125 struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); 126 127 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); 128 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); 129 int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); 130 struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns, 131 struct ipc_ids *ids, int id, int cmd, 132 struct ipc64_perm *perm, int extra_perm); 133 134 #ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION 135 /* On IA-64, we always use the "64-bit version" of the IPC structures. */ 136 # define ipc_parse_version(cmd) IPC_64 137 #else 138 int ipc_parse_version (int *cmd); 139 #endif 140 141 extern void free_msg(struct msg_msg *msg); 142 extern struct msg_msg *load_msg(const void __user *src, int len); 143 extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); 144 extern int store_msg(void __user *dest, struct msg_msg *msg, int len); 145 146 extern void recompute_msgmni(struct ipc_namespace *); 147 148 static inline int ipc_buildid(int id, int seq) 149 { 150 return SEQ_MULTIPLIER * seq + id; 151 } 152 153 /* 154 * Must be called with ipcp locked 155 */ 156 static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) 157 { 158 if (uid / SEQ_MULTIPLIER != ipcp->seq) 159 return 1; 160 return 0; 161 } 162 163 static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm) 164 { 165 rcu_read_lock(); 166 spin_lock(&perm->lock); 167 } 168 169 static inline void ipc_unlock(struct kern_ipc_perm *perm) 170 { 171 spin_unlock(&perm->lock); 172 rcu_read_unlock(); 173 } 174 175 struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id); 176 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, 177 struct ipc_ops *ops, struct ipc_params *params); 178 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, 179 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); 180 #endif 181