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Diffstat (limited to 'include/uapi/linux/msg.h')
| -rw-r--r-- | include/uapi/linux/msg.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/include/uapi/linux/msg.h b/include/uapi/linux/msg.h new file mode 100644 index 000000000..01ee8d54c --- /dev/null +++ b/include/uapi/linux/msg.h @@ -0,0 +1,90 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI_LINUX_MSG_H +#define _UAPI_LINUX_MSG_H + +#include <linux/ipc.h> + +/* ipcs ctl commands */ +#define MSG_STAT 11 +#define MSG_INFO 12 +#define MSG_STAT_ANY 13 + +/* msgrcv options */ +#define MSG_NOERROR 010000 /* no error if message is too big */ +#define MSG_EXCEPT 020000 /* recv any msg except of specified type.*/ +#define MSG_COPY 040000 /* copy (not remove) all queue messages */ + +/* Obsolete, used only for backwards compatibility and libc5 compiles */ +struct msqid_ds { + struct ipc_perm msg_perm; + struct msg *msg_first; /* first message on queue,unused */ + struct msg *msg_last; /* last message in queue,unused */ + __kernel_old_time_t msg_stime; /* last msgsnd time */ + __kernel_old_time_t msg_rtime; /* last msgrcv time */ + __kernel_old_time_t msg_ctime; /* last change time */ + unsigned long msg_lcbytes; /* Reuse junk fields for 32 bit */ + unsigned long msg_lqbytes; /* ditto */ + unsigned short msg_cbytes; /* current number of bytes on queue */ + unsigned short msg_qnum; /* number of messages in queue */ + unsigned short msg_qbytes; /* max number of bytes on queue */ + __kernel_ipc_pid_t msg_lspid; /* pid of last msgsnd */ + __kernel_ipc_pid_t msg_lrpid; /* last receive pid */ +}; + +/* Include the definition of msqid64_ds */ +#include <asm/msgbuf.h> + +/* message buffer for msgsnd and msgrcv calls */ +struct msgbuf { + __kernel_long_t mtype; /* type of message */ + char mtext[1]; /* message text */ +}; + +/* buffer for msgctl calls IPC_INFO, MSG_INFO */ +struct msginfo { + int msgpool; + int msgmap; + int msgmax; + int msgmnb; + int msgmni; + int msgssz; + int msgtql; + unsigned short msgseg; +}; + +/* + * MSGMNI, MSGMAX and MSGMNB are default values which can be + * modified by sysctl. + * + * MSGMNI is the upper limit for the number of messages queues per + * namespace. + * It has been chosen to be as large possible without facilitating + * scenarios where userspace causes overflows when adjusting the limits via + * operations of the form retrieve current limit; add X; update limit". + * + * MSGMNB is the default size of a new message queue. Non-root tasks can + * decrease the size with msgctl(IPC_SET), root tasks + * (actually: CAP_SYS_RESOURCE) can both increase and decrease the queue + * size. The optimal value is application dependent. + * 16384 is used because it was always used (since 0.99.10) + * + * MAXMAX is the maximum size of an individual message, it's a global + * (per-namespace) limit that applies for all message queues. + * It's set to 1/2 of MSGMNB, to ensure that at least two messages fit into + * the queue. This is also an arbitrary choice (since 2.6.0). + */ + +#define MSGMNI 32000 /* <= IPCMNI */ /* max # of msg queue identifiers */ +#define MSGMAX 8192 /* <= INT_MAX */ /* max size of message (bytes) */ +#define MSGMNB 16384 /* <= INT_MAX */ /* default max size of a message queue */ + +/* unused */ +#define MSGPOOL (MSGMNI * MSGMNB / 1024) /* size in kbytes of message pool */ +#define MSGTQL MSGMNB /* number of system message headers */ +#define MSGMAP MSGMNB /* number of entries in message map */ +#define MSGSSZ 16 /* message segment size */ +#define __MSGSEG ((MSGPOOL * 1024) / MSGSSZ) /* max no. of segments */ +#define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff) + + +#endif /* _UAPI_LINUX_MSG_H */ |