[mirror_ubuntu-bionic-kernel.git] / include / uapi / linux / msg.h

/* 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

/* 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_time_t msg_stime;	/* last msgsnd time */
	__kernel_time_t msg_rtime;	/* last msgrcv time */
	__kernel_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 */
Commit	Line	Data
6f52b16c	1	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
607ca46e DH	2	#ifndef _UAPI_LINUX_MSG_H
	3	#define _UAPI_LINUX_MSG_H
	4
	5	#include <linux/ipc.h>
	6
	7	/* ipcs ctl commands */
	8	#define MSG_STAT 11
	9	#define MSG_INFO 12
	10
	11	/* msgrcv options */
	12	#define MSG_NOERROR 010000 /* no error if message is too big */
	13	#define MSG_EXCEPT 020000 /* recv any msg except of specified type.*/
4a674f34	14	#define MSG_COPY 040000 /* copy (not remove) all queue messages */
607ca46e DH	15
	16	/* Obsolete, used only for backwards compatibility and libc5 compiles */
	17	struct msqid_ds {
	18	struct ipc_perm msg_perm;
	19	struct msg msg_first; / first message on queue,unused */
	20	struct msg msg_last; / last message in queue,unused */
	21	__kernel_time_t msg_stime; /* last msgsnd time */
	22	__kernel_time_t msg_rtime; /* last msgrcv time */
	23	__kernel_time_t msg_ctime; /* last change time */
	24	unsigned long msg_lcbytes; /* Reuse junk fields for 32 bit */
	25	unsigned long msg_lqbytes; /* ditto */
	26	unsigned short msg_cbytes; /* current number of bytes on queue */
	27	unsigned short msg_qnum; /* number of messages in queue */
	28	unsigned short msg_qbytes; /* max number of bytes on queue */
	29	__kernel_ipc_pid_t msg_lspid; /* pid of last msgsnd */
	30	__kernel_ipc_pid_t msg_lrpid; /* last receive pid */
	31	};
	32
	33	/* Include the definition of msqid64_ds */
	34	#include <asm/msgbuf.h>
	35
	36	/* message buffer for msgsnd and msgrcv calls */
	37	struct msgbuf {
443d5670 L	38	__kernel_long_t mtype; /* type of message */
443d5670 L	39	char mtext[1]; /* message text */
607ca46e DH	40	};
	41
	42	/* buffer for msgctl calls IPC_INFO, MSG_INFO */
	43	struct msginfo {
	44	int msgpool;
	45	int msgmap;
	46	int msgmax;
	47	int msgmnb;
	48	int msgmni;
	49	int msgssz;
	50	int msgtql;
	51	unsigned short msgseg;
	52	};
	53
	54	/*
0050ee05 MS	55	* MSGMNI, MSGMAX and MSGMNB are default values which can be
	56	* modified by sysctl.
	57	*
	58	* MSGMNI is the upper limit for the number of messages queues per
	59	* namespace.
	60	* It has been chosen to be as large possible without facilitating
	61	* scenarios where userspace causes overflows when adjusting the limits via
	62	* operations of the form retrieve current limit; add X; update limit".
	63	*
	64	* MSGMNB is the default size of a new message queue. Non-root tasks can
	65	* decrease the size with msgctl(IPC_SET), root tasks
	66	* (actually: CAP_SYS_RESOURCE) can both increase and decrease the queue
	67	* size. The optimal value is application dependent.
	68	* 16384 is used because it was always used (since 0.99.10)
	69	*
	70	* MAXMAX is the maximum size of an individual message, it's a global
	71	* (per-namespace) limit that applies for all message queues.
	72	* It's set to 1/2 of MSGMNB, to ensure that at least two messages fit into
	73	* the queue. This is also an arbitrary choice (since 2.6.0).
607ca46e	74	*/
607ca46e	75
0050ee05	76	#define MSGMNI 32000 /* <= IPCMNI / / max # of msg queue identifiers */
607ca46e DH	77	#define MSGMAX 8192 /* <= INT_MAX / / max size of message (bytes) */
	78	#define MSGMNB 16384 /* <= INT_MAX / / default max size of a message queue */
	79
	80	/* unused */
	81	#define MSGPOOL (MSGMNI * MSGMNB / 1024) /* size in kbytes of message pool */
	82	#define MSGTQL MSGMNB /* number of system message headers */
	83	#define MSGMAP MSGMNB /* number of entries in message map */
	84	#define MSGSSZ 16 /* message segment size */
	85	#define __MSGSEG ((MSGPOOL * 1024) / MSGSSZ) /* max no. of segments */
	86	#define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff)
	87
	88
	89	#endif /* _UAPI_LINUX_MSG_H */