1 /* SPDX-License-Identifier: LGPL-2.1+ WITH Linux-syscall-note */
2 /* Copyright (C) 2003 Krzysztof Benedyczak & Michal Wronski
3
4 This program is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 It is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with this software; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA. */
18
19 #ifndef _LINUX_MQUEUE_H
20 #define _LINUX_MQUEUE_H
21
22 #include <linux/types.h>
23
24 #define MQ_PRIO_MAX 32768
25 /* per-uid limit of kernel memory used by mqueue, in bytes */
26 #define MQ_BYTES_MAX 819200
27
28 struct mq_attr {
29 __kernel_long_t mq_flags; /* message queue flags */
30 __kernel_long_t mq_maxmsg; /* maximum number of messages */
31 __kernel_long_t mq_msgsize; /* maximum message size */
32 __kernel_long_t mq_curmsgs; /* number of messages currently queued */
33 __kernel_long_t __reserved[4]; /* ignored for input, zeroed for output */
34 };
35
36 /*
37 * SIGEV_THREAD implementation:
38 * SIGEV_THREAD must be implemented in user space. If SIGEV_THREAD is passed
39 * to mq_notify, then
40 * - sigev_signo must be the file descriptor of an AF_NETLINK socket. It's not
41 * necessary that the socket is bound.
42 * - sigev_value.sival_ptr must point to a cookie that is NOTIFY_COOKIE_LEN
43 * bytes long.
44 * If the notification is triggered, then the cookie is sent to the netlink
45 * socket. The last byte of the cookie is replaced with the NOTIFY_?? codes:
46 * NOTIFY_WOKENUP if the notification got triggered, NOTIFY_REMOVED if it was
47 * removed, either due to a close() on the message queue fd or due to a
48 * mq_notify() that removed the notification.
49 */
50 #define NOTIFY_NONE 0
51 #define NOTIFY_WOKENUP 1
52 #define NOTIFY_REMOVED 2
53
54 #define NOTIFY_COOKIE_LEN 32
55
56 #endif