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