blob: d768fdbed5154a10b279e061b8cc66eff7e166da [file] [log] [blame]
/* 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 <linux/unistd.h>
#include <linux/err.h>
#include <linux/ipc_namespace.h>
#define IPCMNI 32768 /* <= MAX_INT limit for ipc arrays (including sysctl changes) */
void sem_init(void);
void msg_init(void);
void shm_init(void);
struct ipc_namespace;
struct pid_namespace;
extern void mq_clear_sbinfo(struct ipc_namespace *ns);
extern void mq_put_mnt(struct ipc_namespace *ns);
static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
static inline void mq_put_mnt(struct ipc_namespace *ns) { }
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);
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) { }
* 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 *ids);
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 *);
#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
#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)
/* 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_maxidx - get the highest assigned index
* @ids: ipc identifier set
* Called with ipc_ids.rwsem held for reading.
static inline int ipc_get_maxidx(struct ipc_ids *ids)
if (ids->in_use == 0)
return -1;
if (ids->in_use == IPCMNI)
return IPCMNI - 1;
return ids->max_idx;
* 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.
bool 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_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_obtain_check(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);
/* On IA-64, we always use the "64-bit version" of the IPC structures. */
# define ipc_parse_version(cmd) IPC_64
int ipc_parse_version(int *cmd);
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 id)
return ipcid_to_seqx(id) != ipcp->seq;
static inline void ipc_lock_object(struct kern_ipc_perm *perm)
static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
static inline void ipc_unlock(struct kern_ipc_perm *perm)
* 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 *));
static inline int sem_check_semmni(struct ipc_namespace *ns) {
* Check semmni range [0, IPCMNI]
* semmni is the last element of sem_ctls[4] array
return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > IPCMNI))
? -ERANGE : 0;
#include <linux/compat.h>
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)
int version = *cmd & IPC_64;
*cmd &= ~IPC_64;
return version;
return IPC_64;
/* for __ARCH_WANT_SYS_IPC */
long ksys_semtimedop(int semid, struct sembuf __user *tsops,
unsigned int nsops,
const struct __kernel_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_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);
long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
long msgtyp, int msgflg);
long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
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);
long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
unsigned int nsops,
const struct old_timespec32 __user *timeout);
long compat_ksys_semctl(int semid, int semnum, int cmd, int arg);
long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr);
long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
compat_long_t msgtyp, int msgflg);
long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
compat_ssize_t msgsz, int msgflg);
long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr);
#endif /* CONFIG_COMPAT */