linux/include/linux/msg.h
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   1#ifndef _LINUX_MSG_H
   2#define _LINUX_MSG_H
   3
   4#include <linux/ipc.h>
   5
   6/* ipcs ctl commands */
   7#define MSG_STAT 11
   8#define MSG_INFO 12
   9
  10/* msgrcv options */
  11#define MSG_NOERROR     010000  /* no error if message is too big */
  12#define MSG_EXCEPT      020000  /* recv any msg except of specified type.*/
  13
  14/* Obsolete, used only for backwards compatibility and libc5 compiles */
  15struct msqid_ds {
  16        struct ipc_perm msg_perm;
  17        struct msg *msg_first;          /* first message on queue,unused  */
  18        struct msg *msg_last;           /* last message in queue,unused */
  19        __kernel_time_t msg_stime;      /* last msgsnd time */
  20        __kernel_time_t msg_rtime;      /* last msgrcv time */
  21        __kernel_time_t msg_ctime;      /* last change time */
  22        unsigned long  msg_lcbytes;     /* Reuse junk fields for 32 bit */
  23        unsigned long  msg_lqbytes;     /* ditto */
  24        unsigned short msg_cbytes;      /* current number of bytes on queue */
  25        unsigned short msg_qnum;        /* number of messages in queue */
  26        unsigned short msg_qbytes;      /* max number of bytes on queue */
  27        __kernel_ipc_pid_t msg_lspid;   /* pid of last msgsnd */
  28        __kernel_ipc_pid_t msg_lrpid;   /* last receive pid */
  29};
  30
  31/* Include the definition of msqid64_ds */
  32#include <asm/msgbuf.h>
  33
  34/* message buffer for msgsnd and msgrcv calls */
  35struct msgbuf {
  36        long mtype;         /* type of message */
  37        char mtext[1];      /* message text */
  38};
  39
  40/* buffer for msgctl calls IPC_INFO, MSG_INFO */
  41struct msginfo {
  42        int msgpool;
  43        int msgmap; 
  44        int msgmax; 
  45        int msgmnb; 
  46        int msgmni; 
  47        int msgssz; 
  48        int msgtql; 
  49        unsigned short  msgseg; 
  50};
  51
  52/*
  53 * Scaling factor to compute msgmni:
  54 * the memory dedicated to msg queues (msgmni * msgmnb) should occupy
  55 * at most 1/MSG_MEM_SCALE of the lowmem (see the formula in ipc/msg.c):
  56 * up to 8MB       : msgmni = 16 (MSGMNI)
  57 * 4 GB            : msgmni = 8K
  58 * more than 16 GB : msgmni = 32K (IPCMNI)
  59 */
  60#define MSG_MEM_SCALE 32
  61
  62#define MSGMNI    16   /* <= IPCMNI */     /* max # of msg queue identifiers */
  63#define MSGMAX  8192   /* <= INT_MAX */   /* max size of message (bytes) */
  64#define MSGMNB 16384   /* <= INT_MAX */   /* default max size of a message queue */
  65
  66/* unused */
  67#define MSGPOOL (MSGMNI * MSGMNB / 1024) /* size in kbytes of message pool */
  68#define MSGTQL  MSGMNB            /* number of system message headers */
  69#define MSGMAP  MSGMNB            /* number of entries in message map */
  70#define MSGSSZ  16                /* message segment size */
  71#define __MSGSEG ((MSGPOOL * 1024) / MSGSSZ) /* max no. of segments */
  72#define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff)
  73
  74#ifdef __KERNEL__
  75#include <linux/list.h>
  76
  77/* one msg_msg structure for each message */
  78struct msg_msg {
  79        struct list_head m_list; 
  80        long  m_type;          
  81        int m_ts;           /* message text size */
  82        struct msg_msgseg* next;
  83        void *security;
  84        /* the actual message follows immediately */
  85};
  86
  87/* one msq_queue structure for each present queue on the system */
  88struct msg_queue {
  89        struct kern_ipc_perm q_perm;
  90        time_t q_stime;                 /* last msgsnd time */
  91        time_t q_rtime;                 /* last msgrcv time */
  92        time_t q_ctime;                 /* last change time */
  93        unsigned long q_cbytes;         /* current number of bytes on queue */
  94        unsigned long q_qnum;           /* number of messages in queue */
  95        unsigned long q_qbytes;         /* max number of bytes on queue */
  96        pid_t q_lspid;                  /* pid of last msgsnd */
  97        pid_t q_lrpid;                  /* last receive pid */
  98
  99        struct list_head q_messages;
 100        struct list_head q_receivers;
 101        struct list_head q_senders;
 102};
 103
 104/* Helper routines for sys_msgsnd and sys_msgrcv */
 105extern long do_msgsnd(int msqid, long mtype, void __user *mtext,
 106                        size_t msgsz, int msgflg);
 107extern long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
 108                        size_t msgsz, long msgtyp, int msgflg);
 109
 110#endif /* __KERNEL__ */
 111
 112#endif /* _LINUX_MSG_H */
 113
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