/* SPDX-License-Identifier: GPL-2.0 */ /* * linux/ipc/util.h * Copyright (C) 1999 Christoph Rohland * * ipc helper functions (c) 1999 Manfred Spraul * namespaces support. 2006 OpenVZ, SWsoft Inc. * Pavel Emelianov */ #ifndef _IPC_UTIL_H #define _IPC_UTIL_H #include #include #include #define SEQ_MULTIPLIER (IPCMNI) int sem_init(void); int msg_init(void); void shm_init(void); struct ipc_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 int sem_init_ns(struct ipc_namespace *ns); int msg_init_ns(struct ipc_namespace *ns); int 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 int sem_init_ns(struct ipc_namespace *ns) { return 0; } static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; } static inline int shm_init_ns(struct ipc_namespace *ns) { return 0; } 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 /* * 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; int 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 *)); #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 both locks acquired. */ void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); /* must be called with both locks acquired. */ void ipc_set_key_private(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); /** * ipc_get_maxid - get the last assigned id * @ids: ipc identifier set * * Called with ipc_ids.rwsem held for reading. */ static inline int ipc_get_maxid(struct ipc_ids *ids) { if (ids->in_use == 0) return -1; if (ids->in_use == IPCMNI) return IPCMNI - 1; return ids->max_id; } /* * 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. * * refcount is initialized by ipc_addid(), before that point call_rcu() * must be used. */ int ipc_rcu_getref(struct kern_ipc_perm *ptr); void ipc_rcu_putref(struct kern_ipc_perm *ptr, void (*func)(struct rcu_head *head)); struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); struct kern_ipc_perm *ipc_obtain_object_idr(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); #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); 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 *)); #ifdef CONFIG_COMPAT #include struct compat_ipc_perm { key_t key; __compat_uid_t uid; __compat_gid_t gid; __compat_uid_t cuid; __compat_gid_t cgid; compat_mode_t mode; unsigned short seq; }; void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *); void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *); int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *); int get_compat_ipc64_perm(struct ipc64_perm *, struct compat_ipc64_perm __user *); static inline int compat_ipc_parse_version(int *cmd) { #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION int version = *cmd & IPC_64; *cmd &= ~IPC_64; return version; #else return IPC_64; #endif } #endif /* for __ARCH_WANT_SYS_IPC */ long ksys_semtimedop(int semid, struct sembuf __user *tsops, unsigned int nsops, const struct timespec __user *timeout); long ksys_semget(key_t key, int nsems, int semflg); long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg); long ksys_msgget(key_t key, int msgflg); long ksys_shmget(key_t key, size_t size, int shmflg); long ksys_shmdt(char __user *shmaddr); long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf); /* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */ #ifdef CONFIG_COMPAT long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems, unsigned int nsops, const struct compat_timespec __user *timeout); long compat_ksys_semctl(int semid, int semnum, int cmd, int arg); long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr); #endif /* CONFIG_COMPAT */ #endif