include/uapi/linux/msg.h

   1 #ifndef _UAPI_LINUX_MSG_H
   2 #define _UAPI_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 #define MSG_COPY        040000  /* copy (not remove) all queue messages */
  14
  15 /* Obsolete, used only for backwards compatibility and libc5 compiles */
  16 struct msqid_ds {
  17         struct ipc_perm msg_perm;
  18         struct msg *msg_first;          /* first message on queue,unused  */
  19         struct msg *msg_last;           /* last message in queue,unused */
  20         __kernel_time_t msg_stime;      /* last msgsnd time */
  21         __kernel_time_t msg_rtime;      /* last msgrcv time */
  22         __kernel_time_t msg_ctime;      /* last change time */
  23         unsigned long  msg_lcbytes;     /* Reuse junk fields for 32 bit */
  24         unsigned long  msg_lqbytes;     /* ditto */
  25         unsigned short msg_cbytes;      /* current number of bytes on queue */
  26         unsigned short msg_qnum;        /* number of messages in queue */
  27         unsigned short msg_qbytes;      /* max number of bytes on queue */
  28         __kernel_ipc_pid_t msg_lspid;   /* pid of last msgsnd */
  29         __kernel_ipc_pid_t msg_lrpid;   /* last receive pid */
  30 };
  31
  32 /* Include the definition of msqid64_ds */
  33 #include <asm/msgbuf.h>
  34
  35 /* message buffer for msgsnd and msgrcv calls */
  36 struct msgbuf {
  37         long mtype;         /* type of message */
  38         char mtext[1];      /* message text */
  39 };
  40
  41 /* buffer for msgctl calls IPC_INFO, MSG_INFO */
  42 struct msginfo {
  43         int msgpool;
  44         int msgmap;
  45         int msgmax;
  46         int msgmnb;
  47         int msgmni;
  48         int msgssz;
  49         int msgtql;
  50         unsigned short  msgseg;
  51 };
  52
  53 /*
  54  * Scaling factor to compute msgmni:
  55  * the memory dedicated to msg queues (msgmni * msgmnb) should occupy
  56  * at most 1/MSG_MEM_SCALE of the lowmem (see the formula in ipc/msg.c):
  57  * up to 8MB       : msgmni = 16 (MSGMNI)
  58  * 4 GB            : msgmni = 8K
  59  * more than 16 GB : msgmni = 32K (IPCMNI)
  60  */
  61 #define MSG_MEM_SCALE 32
  62
  63 #define MSGMNI    16   /* <= IPCMNI */     /* max # of msg queue identifiers */
  64 #define MSGMAX  8192   /* <= INT_MAX */   /* max size of message (bytes) */
  65 #define MSGMNB 16384   /* <= INT_MAX */   /* default max size of a message queue */
  66
  67 /* unused */
  68 #define MSGPOOL (MSGMNI * MSGMNB / 1024) /* size in kbytes of message pool */
  69 #define MSGTQL  MSGMNB            /* number of system message headers */
  70 #define MSGMAP  MSGMNB            /* number of entries in message map */
  71 #define MSGSSZ  16                /* message segment size */
  72 #define __MSGSEG ((MSGPOOL * 1024) / MSGSSZ) /* max no. of segments */
  73 #define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff)
  74
  75
  76 #endif /* _UAPI_LINUX_MSG_H */