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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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4a674f34ba
This patch is required for checkpoint/restore in userspace. c/r requires some way to get all pending IPC messages without deleting them from the queue (checkpoint can fail and in this case tasks will be resumed, so queue have to be valid). To achive this, new operation flag MSG_COPY for sys_msgrcv() system call was introduced. If this flag was specified, then mtype is interpreted as number of the message to copy. If MSG_COPY is set, then kernel will allocate dummy message with passed size, and then use new copy_msg() helper function to copy desired message (instead of unlinking it from the queue). Notes: 1) Return -ENOSYS if MSG_COPY is specified, but CONFIG_CHECKPOINT_RESTORE is not set. Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Cc: Serge Hallyn <serge.hallyn@canonical.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
181 lines
5.4 KiB
C
181 lines
5.4 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/unistd.h>
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#include <linux/err.h>
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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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#ifdef CONFIG_POSIX_MQUEUE
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extern void mq_clear_sbinfo(struct ipc_namespace *ns);
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extern void mq_put_mnt(struct ipc_namespace *ns);
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#else
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static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
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static inline void mq_put_mnt(struct ipc_namespace *ns) { }
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#endif
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#ifdef CONFIG_SYSVIPC
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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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#else
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static inline void sem_init_ns(struct ipc_namespace *ns) { }
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static inline void msg_init_ns(struct ipc_namespace *ns) { }
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static inline void shm_init_ns(struct ipc_namespace *ns) { }
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static inline void sem_exit_ns(struct ipc_namespace *ns) { }
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static inline void msg_exit_ns(struct ipc_namespace *ns) { }
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static inline void shm_exit_ns(struct ipc_namespace *ns) { }
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#endif
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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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#define ipcid_to_seqx(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 ipc_namespace *ns, 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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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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int 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_namespace *ns,
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struct ipc_ids *ids, int id, int cmd,
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struct ipc64_perm *perm, int extra_perm);
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#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
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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 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
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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(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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void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
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void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
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#endif
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