diff options
Diffstat (limited to 'ipc/util.h')
| -rw-r--r-- | ipc/util.h | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/ipc/util.h b/ipc/util.h index 59d78aa94987..9c47d6f6c7b4 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -15,9 +15,9 @@ #define SEQ_MULTIPLIER (IPCMNI) -void sem_init (void); -void msg_init (void); -void shm_init (void); +void sem_init(void); +void msg_init(void); +void shm_init(void); struct ipc_namespace; @@ -100,6 +100,7 @@ void __init ipc_init_proc_interface(const char *path, const char *header, #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); @@ -116,8 +117,8 @@ 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); +void *ipc_alloc(int size); +void ipc_free(void *ptr, int size); /* * For allocation that need to be freed by RCU. @@ -125,7 +126,7 @@ void ipc_free(void* ptr, int size); * 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); +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); @@ -144,7 +145,7 @@ struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, /* 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); +int ipc_parse_version(int *cmd); #endif extern void free_msg(struct msg_msg *msg); @@ -185,6 +186,19 @@ static inline void ipc_unlock(struct kern_ipc_perm *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, struct ipc_ops *ops, struct ipc_params *params); |