root/include/linux/msg.h

INCLUDED FROM

#ifndef _LINUX_MSG_H
#define _LINUX_MSG_H

#include <linux/list.h>
#include <uapi/linux/msg.h>

/* one msg_msg structure for each message */
struct msg_msg {
        struct list_head m_list;
        long m_type;
        size_t m_ts;            /* message text size */
        struct msg_msgseg *next;
        void *security;
        /* the actual message follows immediately */
};

/* one msq_queue structure for each present queue on the system */
struct msg_queue {
        struct kern_ipc_perm q_perm;
        time_t q_stime;                 /* last msgsnd time */
        time_t q_rtime;                 /* last msgrcv time */
        time_t q_ctime;                 /* last change time */
        unsigned long q_cbytes;         /* current number of bytes on queue */
        unsigned long q_qnum;           /* number of messages in queue */
        unsigned long q_qbytes;         /* max number of bytes on queue */
        pid_t q_lspid;                  /* pid of last msgsnd */
        pid_t q_lrpid;                  /* last receive pid */

        struct list_head q_messages;
        struct list_head q_receivers;
        struct list_head q_senders;
};

/* Helper routines for sys_msgsnd and sys_msgrcv */
extern long do_msgsnd(int msqid, long mtype, void __user *mtext,
                        size_t msgsz, int msgflg);
extern long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
                      int msgflg,
                      long (*msg_fill)(void __user *, struct msg_msg *,
                                       size_t));

#endif /* _LINUX_MSG_H */