xref: /openbmc/linux/include/uapi/linux/mqueue.h (revision 607ca46e)
1607ca46eSDavid Howells /* Copyright (C) 2003 Krzysztof Benedyczak & Michal Wronski
2607ca46eSDavid Howells 
3607ca46eSDavid Howells    This program is free software; you can redistribute it and/or
4607ca46eSDavid Howells    modify it under the terms of the GNU Lesser General Public
5607ca46eSDavid Howells    License as published by the Free Software Foundation; either
6607ca46eSDavid Howells    version 2.1 of the License, or (at your option) any later version.
7607ca46eSDavid Howells 
8607ca46eSDavid Howells    It is distributed in the hope that it will be useful,
9607ca46eSDavid Howells    but WITHOUT ANY WARRANTY; without even the implied warranty of
10607ca46eSDavid Howells    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11607ca46eSDavid Howells    Lesser General Public License for more details.
12607ca46eSDavid Howells 
13607ca46eSDavid Howells    You should have received a copy of the GNU Lesser General Public
14607ca46eSDavid Howells    License along with this software; if not, write to the Free
15607ca46eSDavid Howells    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
16607ca46eSDavid Howells    02111-1307 USA.  */
17607ca46eSDavid Howells 
18607ca46eSDavid Howells #ifndef _LINUX_MQUEUE_H
19607ca46eSDavid Howells #define _LINUX_MQUEUE_H
20607ca46eSDavid Howells 
21607ca46eSDavid Howells #define MQ_PRIO_MAX 	32768
22607ca46eSDavid Howells /* per-uid limit of kernel memory used by mqueue, in bytes */
23607ca46eSDavid Howells #define MQ_BYTES_MAX	819200
24607ca46eSDavid Howells 
25607ca46eSDavid Howells struct mq_attr {
26607ca46eSDavid Howells 	long	mq_flags;	/* message queue flags			*/
27607ca46eSDavid Howells 	long	mq_maxmsg;	/* maximum number of messages		*/
28607ca46eSDavid Howells 	long	mq_msgsize;	/* maximum message size			*/
29607ca46eSDavid Howells 	long	mq_curmsgs;	/* number of messages currently queued	*/
30607ca46eSDavid Howells 	long	__reserved[4];	/* ignored for input, zeroed for output */
31607ca46eSDavid Howells };
32607ca46eSDavid Howells 
33607ca46eSDavid Howells /*
34607ca46eSDavid Howells  * SIGEV_THREAD implementation:
35607ca46eSDavid Howells  * SIGEV_THREAD must be implemented in user space. If SIGEV_THREAD is passed
36607ca46eSDavid Howells  * to mq_notify, then
37607ca46eSDavid Howells  * - sigev_signo must be the file descriptor of an AF_NETLINK socket. It's not
38607ca46eSDavid Howells  *   necessary that the socket is bound.
39607ca46eSDavid Howells  * - sigev_value.sival_ptr must point to a cookie that is NOTIFY_COOKIE_LEN
40607ca46eSDavid Howells  *   bytes long.
41607ca46eSDavid Howells  * If the notification is triggered, then the cookie is sent to the netlink
42607ca46eSDavid Howells  * socket. The last byte of the cookie is replaced with the NOTIFY_?? codes:
43607ca46eSDavid Howells  * NOTIFY_WOKENUP if the notification got triggered, NOTIFY_REMOVED if it was
44607ca46eSDavid Howells  * removed, either due to a close() on the message queue fd or due to a
45607ca46eSDavid Howells  * mq_notify() that removed the notification.
46607ca46eSDavid Howells  */
47607ca46eSDavid Howells #define NOTIFY_NONE	0
48607ca46eSDavid Howells #define NOTIFY_WOKENUP	1
49607ca46eSDavid Howells #define NOTIFY_REMOVED	2
50607ca46eSDavid Howells 
51607ca46eSDavid Howells #define NOTIFY_COOKIE_LEN	32
52607ca46eSDavid Howells 
53607ca46eSDavid Howells #endif
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