| /* |
| * linux/ipc/util.h |
| * Copyright (C) 1999 Christoph Rohland |
| * |
| * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com> |
| * namespaces support. 2006 OpenVZ, SWsoft Inc. |
| * Pavel Emelianov <xemul@openvz.org> |
| */ |
| |
| #ifndef _IPC_UTIL_H |
| #define _IPC_UTIL_H |
| |
| #include <linux/unistd.h> |
| #include <linux/err.h> |
| |
| #define SEQ_MULTIPLIER (IPCMNI) |
| |
| void sem_init(void); |
| void msg_init(void); |
| void shm_init(void); |
| |
| struct ipc_namespace; |
| struct pid_namespace; |
| |
| #ifdef CONFIG_POSIX_MQUEUE |
| extern void mq_clear_sbinfo(struct ipc_namespace *ns); |
| extern void mq_put_mnt(struct ipc_namespace *ns); |
| #else |
| static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { } |
| static inline void mq_put_mnt(struct ipc_namespace *ns) { } |
| #endif |
| |
| #ifdef CONFIG_SYSVIPC |
| void sem_init_ns(struct ipc_namespace *ns); |
| void msg_init_ns(struct ipc_namespace *ns); |
| void shm_init_ns(struct ipc_namespace *ns); |
| |
| void sem_exit_ns(struct ipc_namespace *ns); |
| void msg_exit_ns(struct ipc_namespace *ns); |
| void shm_exit_ns(struct ipc_namespace *ns); |
| #else |
| static inline void sem_init_ns(struct ipc_namespace *ns) { } |
| static inline void msg_init_ns(struct ipc_namespace *ns) { } |
| static inline void shm_init_ns(struct ipc_namespace *ns) { } |
| |
| static inline void sem_exit_ns(struct ipc_namespace *ns) { } |
| static inline void msg_exit_ns(struct ipc_namespace *ns) { } |
| static inline void shm_exit_ns(struct ipc_namespace *ns) { } |
| #endif |
| |
| struct ipc_rcu { |
| struct rcu_head rcu; |
| atomic_t refcount; |
| } ____cacheline_aligned_in_smp; |
| |
| #define ipc_rcu_to_struct(p) ((void *)(p+1)) |
| |
| /* |
| * Structure that holds the parameters needed by the ipc operations |
| * (see after) |
| */ |
| struct ipc_params { |
| key_t key; |
| int flg; |
| union { |
| size_t size; /* for shared memories */ |
| int nsems; /* for semaphores */ |
| } u; /* holds the getnew() specific param */ |
| }; |
| |
| /* |
| * Structure that holds some ipc operations. This structure is used to unify |
| * the calls to sys_msgget(), sys_semget(), sys_shmget() |
| * . routine to call to create a new ipc object. Can be one of newque, |
| * newary, newseg |
| * . routine to call to check permissions for a new ipc object. |
| * Can be one of security_msg_associate, security_sem_associate, |
| * security_shm_associate |
| * . routine to call for an extra check if needed |
| */ |
| struct ipc_ops { |
| int (*getnew)(struct ipc_namespace *, struct ipc_params *); |
| int (*associate)(struct kern_ipc_perm *, int); |
| int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *); |
| }; |
| |
| struct seq_file; |
| struct ipc_ids; |
| |
| void ipc_init_ids(struct ipc_ids *); |
| #ifdef CONFIG_PROC_FS |
| void __init ipc_init_proc_interface(const char *path, const char *header, |
| int ids, int (*show)(struct seq_file *, void *)); |
| struct pid_namespace *ipc_seq_pid_ns(struct seq_file *); |
| #else |
| #define ipc_init_proc_interface(path, header, ids, show) do {} while (0) |
| #endif |
| |
| #define IPC_SEM_IDS 0 |
| #define IPC_MSG_IDS 1 |
| #define IPC_SHM_IDS 2 |
| |
| #define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER) |
| #define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER) |
| #define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX) |
| |
| /* must be called with ids->rwsem acquired for writing */ |
| int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); |
| |
| /* must be called with ids->rwsem acquired for reading */ |
| int ipc_get_maxid(struct ipc_ids *); |
| |
| /* must be called with both locks acquired. */ |
| void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); |
| |
| /* must be called with ipcp locked */ |
| int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg); |
| |
| /* for rare, potentially huge allocations. |
| * both function can sleep |
| */ |
| void *ipc_alloc(int size); |
| void ipc_free(void *ptr, int size); |
| |
| /* |
| * For allocation that need to be freed by RCU. |
| * Objects are reference counted, they start with reference count 1. |
| * getref increases the refcount, the putref call that reduces the recount |
| * to 0 schedules the rcu destruction. Caller must guarantee locking. |
| */ |
| void *ipc_rcu_alloc(int size); |
| int ipc_rcu_getref(void *ptr); |
| void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head)); |
| void ipc_rcu_free(struct rcu_head *head); |
| |
| struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); |
| struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id); |
| |
| void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); |
| void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); |
| int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); |
| struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, |
| struct ipc_ids *ids, int id, int cmd, |
| struct ipc64_perm *perm, int extra_perm); |
| |
| static inline void ipc_update_pid(struct pid **pos, struct pid *pid) |
| { |
| struct pid *old = *pos; |
| if (old != pid) { |
| *pos = get_pid(pid); |
| put_pid(old); |
| } |
| } |
| |
| #ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
| /* On IA-64, we always use the "64-bit version" of the IPC structures. */ |
| # define ipc_parse_version(cmd) IPC_64 |
| #else |
| int ipc_parse_version(int *cmd); |
| #endif |
| |
| extern void free_msg(struct msg_msg *msg); |
| extern struct msg_msg *load_msg(const void __user *src, size_t len); |
| extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); |
| extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len); |
| |
| extern void recompute_msgmni(struct ipc_namespace *); |
| |
| static inline int ipc_buildid(int id, int seq) |
| { |
| return SEQ_MULTIPLIER * seq + id; |
| } |
| |
| static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) |
| { |
| return uid / SEQ_MULTIPLIER != ipcp->seq; |
| } |
| |
| static inline void ipc_lock_object(struct kern_ipc_perm *perm) |
| { |
| spin_lock(&perm->lock); |
| } |
| |
| static inline void ipc_unlock_object(struct kern_ipc_perm *perm) |
| { |
| spin_unlock(&perm->lock); |
| } |
| |
| static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm) |
| { |
| assert_spin_locked(&perm->lock); |
| } |
| |
| static inline void ipc_unlock(struct kern_ipc_perm *perm) |
| { |
| ipc_unlock_object(perm); |
| rcu_read_unlock(); |
| } |
| |
| /* |
| * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths |
| * where the respective ipc_ids.rwsem is not being held down. |
| * Checks whether the ipc object is still around or if it's gone already, as |
| * ipc_rmid() may have already freed the ID while the ipc lock was spinning. |
| * Needs to be called with kern_ipc_perm.lock held -- exception made for one |
| * checkpoint case at sys_semtimedop() as noted in code commentary. |
| */ |
| static inline bool ipc_valid_object(struct kern_ipc_perm *perm) |
| { |
| return !perm->deleted; |
| } |
| |
| struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id); |
| int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, |
| const struct ipc_ops *ops, struct ipc_params *params); |
| void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, |
| void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); |
| #endif |