include/linux/msg.h

   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 */
  15 struct 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 */
  35 struct msgbuf {
  36         long mtype;         /* type of message */
  37         char mtext[1];      /* message text */
  38 };
  39
  40 /* buffer for msgctl calls IPC_INFO, MSG_INFO */
  41 struct 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) /* size in bytes 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 / 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 */
  78 struct 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 */
  88 struct 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 */
 105 extern long do_msgsnd(int msqid, long mtype, void __user *mtext,
 106                         size_t msgsz, int msgflg);
 107 extern 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 */