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 __kernel_long_t 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 * MSGMNI, MSGMAX and MSGMNB are default values which can be 55 * modified by sysctl. 56 * 57 * MSGMNI is the upper limit for the number of messages queues per 58 * namespace. 59 * It has been chosen to be as large possible without facilitating 60 * scenarios where userspace causes overflows when adjusting the limits via 61 * operations of the form retrieve current limit; add X; update limit". 62 * 63 * MSGMNB is the default size of a new message queue. Non-root tasks can 64 * decrease the size with msgctl(IPC_SET), root tasks 65 * (actually: CAP_SYS_RESOURCE) can both increase and decrease the queue 66 * size. The optimal value is application dependent. 67 * 16384 is used because it was always used (since 0.99.10) 68 * 69 * MAXMAX is the maximum size of an individual message, it's a global 70 * (per-namespace) limit that applies for all message queues. 71 * It's set to 1/2 of MSGMNB, to ensure that at least two messages fit into 72 * the queue. This is also an arbitrary choice (since 2.6.0). 73 */ 74 75 #define MSGMNI 32000 /* <= IPCMNI */ /* max # of msg queue identifiers */ 76 #define MSGMAX 8192 /* <= INT_MAX */ /* max size of message (bytes) */ 77 #define MSGMNB 16384 /* <= INT_MAX */ /* default max size of a message queue */ 78 79 /* unused */ 80 #define MSGPOOL (MSGMNI * MSGMNB / 1024) /* size in kbytes of message pool */ 81 #define MSGTQL MSGMNB /* number of system message headers */ 82 #define MSGMAP MSGMNB /* number of entries in message map */ 83 #define MSGSSZ 16 /* message segment size */ 84 #define __MSGSEG ((MSGPOOL * 1024) / MSGSSZ) /* max no. of segments */ 85 #define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff) 86 87 88 #endif /* _UAPI_LINUX_MSG_H */ 89
