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 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); 128void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); 129struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd, 130 struct ipc64_perm *perm, int extra_perm); 131 132#ifndef __ARCH_WANT_IPC_PARSE_VERSION 133 /* On IA-64, we always use the "64-bit version" of the IPC structures. */ 134# define ipc_parse_version(cmd) IPC_64 135#else 136int ipc_parse_version (int *cmd); 137#endif 138 139extern void free_msg(struct msg_msg *msg); 140extern struct msg_msg *load_msg(const void __user *src, int len); 141extern int store_msg(void __user *dest, struct msg_msg *msg, int len); 142 143extern void recompute_msgmni(struct ipc_namespace *); 144 145static inline int ipc_buildid(int id, int seq) 146{ 147 return SEQ_MULTIPLIER * seq + id; 148} 149 150/* 151 * Must be called with ipcp locked 152 */ 153static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) 154{ 155 if (uid / SEQ_MULTIPLIER != ipcp->seq) 156 return 1; 157 return 0; 158} 159 160static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm) 161{ 162 rcu_read_lock(); 163 spin_lock(&perm->lock); 164} 165 166static inline void ipc_unlock(struct kern_ipc_perm *perm) 167{ 168 spin_unlock(&perm->lock); 169 rcu_read_unlock(); 170} 171 172struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id); 173int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, 174 struct ipc_ops *ops, struct ipc_params *params); 175void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, 176 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); 177#endif 178