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![Pierre Peiffer](/assets/img/avatar_default.png)
semctl_down(), msgctl_down() and shmctl_down() are used to handle the same set of commands for each kind of IPC. They all start to do the same job (they retrieve the ipc and do some permission checks) before handling the commands on their own. This patch proposes to consolidate this by moving these same pieces of code into one common function called ipcctl_pre_down(). It simplifies a little these xxxctl_down() functions and increases a little the maintainability. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
164 lines
4.7 KiB
C
164 lines
4.7 KiB
C
/*
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* linux/ipc/util.h
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* Copyright (C) 1999 Christoph Rohland
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*
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* ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
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* namespaces support. 2006 OpenVZ, SWsoft Inc.
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* Pavel Emelianov <xemul@openvz.org>
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*/
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#ifndef _IPC_UTIL_H
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#define _IPC_UTIL_H
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#include <linux/err.h>
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#define USHRT_MAX 0xffff
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#define SEQ_MULTIPLIER (IPCMNI)
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void sem_init (void);
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void msg_init (void);
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void shm_init (void);
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struct ipc_namespace;
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void sem_init_ns(struct ipc_namespace *ns);
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void msg_init_ns(struct ipc_namespace *ns);
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void shm_init_ns(struct ipc_namespace *ns);
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void sem_exit_ns(struct ipc_namespace *ns);
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void msg_exit_ns(struct ipc_namespace *ns);
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void shm_exit_ns(struct ipc_namespace *ns);
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/*
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* Structure that holds the parameters needed by the ipc operations
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* (see after)
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*/
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struct ipc_params {
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key_t key;
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int flg;
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union {
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size_t size; /* for shared memories */
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int nsems; /* for semaphores */
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} u; /* holds the getnew() specific param */
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};
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/*
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* Structure that holds some ipc operations. This structure is used to unify
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* the calls to sys_msgget(), sys_semget(), sys_shmget()
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* . routine to call to create a new ipc object. Can be one of newque,
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* newary, newseg
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* . routine to call to check permissions for a new ipc object.
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* Can be one of security_msg_associate, security_sem_associate,
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* security_shm_associate
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* . routine to call for an extra check if needed
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*/
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struct ipc_ops {
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int (*getnew) (struct ipc_namespace *, struct ipc_params *);
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int (*associate) (struct kern_ipc_perm *, int);
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int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
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};
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struct seq_file;
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struct ipc_ids;
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void ipc_init_ids(struct ipc_ids *);
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#ifdef CONFIG_PROC_FS
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void __init ipc_init_proc_interface(const char *path, const char *header,
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int ids, int (*show)(struct seq_file *, void *));
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#else
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#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
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#endif
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#define IPC_SEM_IDS 0
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#define IPC_MSG_IDS 1
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#define IPC_SHM_IDS 2
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#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
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/* must be called with ids->rw_mutex acquired for writing */
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int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
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/* must be called with ids->rw_mutex acquired for reading */
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int ipc_get_maxid(struct ipc_ids *);
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/* must be called with both locks acquired. */
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void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
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/* must be called with ipcp locked */
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int ipcperms(struct kern_ipc_perm *ipcp, short flg);
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/* for rare, potentially huge allocations.
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* both function can sleep
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*/
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void* ipc_alloc(int size);
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void ipc_free(void* ptr, int size);
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/*
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* For allocation that need to be freed by RCU.
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* Objects are reference counted, they start with reference count 1.
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* getref increases the refcount, the putref call that reduces the recount
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* to 0 schedules the rcu destruction. Caller must guarantee locking.
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*/
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void* ipc_rcu_alloc(int size);
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void ipc_rcu_getref(void *ptr);
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void ipc_rcu_putref(void *ptr);
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/*
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* ipc_lock_down: called with rw_mutex held
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* ipc_lock: called without that lock held
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*/
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struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *, int);
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struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
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void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
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void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
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void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
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struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
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struct ipc64_perm *perm, int extra_perm);
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#if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__) || defined(__XTENSA__)
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/* On IA-64, we always use the "64-bit version" of the IPC structures. */
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# define ipc_parse_version(cmd) IPC_64
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#else
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int ipc_parse_version (int *cmd);
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#endif
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extern void free_msg(struct msg_msg *msg);
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extern struct msg_msg *load_msg(const void __user *src, int len);
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extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
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extern void recompute_msgmni(struct ipc_namespace *);
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static inline int ipc_buildid(int id, int seq)
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{
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return SEQ_MULTIPLIER * seq + id;
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}
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/*
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* Must be called with ipcp locked
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*/
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static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
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{
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if (uid / SEQ_MULTIPLIER != ipcp->seq)
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return 1;
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return 0;
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}
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static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
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{
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rcu_read_lock();
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spin_lock(&perm->lock);
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}
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static inline void ipc_unlock(struct kern_ipc_perm *perm)
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{
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spin_unlock(&perm->lock);
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rcu_read_unlock();
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}
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struct kern_ipc_perm *ipc_lock_check_down(struct ipc_ids *ids, int id);
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struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
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int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
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struct ipc_ops *ops, struct ipc_params *params);
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#endif
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