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