sys/sys/mqueue.h

   1 /*      $NetBSD: mqueue.h,v 1.7 2009/04/11 15:47:34 christos Exp $      */
   2
   3 /*
   4  * Copyright (c) 2007, Mindaugas Rasiukevicius <rmind at NetBSD org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #ifndef _SYS_MQUEUE_H_
  30 #define _SYS_MQUEUE_H_
  31
  32 /* Maximal number of mqueue descriptors, that process could open */
  33 #define MQ_OPEN_MAX             512
  34
  35 /* Maximal priority of the message */
  36 #define MQ_PRIO_MAX             32
  37
  38 typedef int             mqd_t;          /* message queue descriptor */
  39
  40 struct mq_attr {
  41         long    mq_flags;       /* Flags of message queue */
  42         long    mq_maxmsg;      /* Maximum number of messages */
  43         long    mq_msgsize;     /* Maximum size of the message */
  44         long    mq_curmsgs;     /* Count of the queued messages */
  45 };
  46
  47 /* Internal kernel data */
  48 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
  49
  50 #include <sys/types.h>
  51 #include <sys/lock.h>
  52 #include <sys/queue.h>
  53 #include <sys/event.h>
  54 #include <sys/signal.h>
  55
  56 /*
  57  * Flags below are used in mq_flags for internal
  58  * purposes, this is appropriate according to POSIX.
  59  */
  60
  61 /* Message queue is unlinking */
  62 #define MQ_UNLINK               0x10000000
  63 /* There are receive-waiters */
  64 #define MQ_RECEIVE              0x20000000
  65
  66 /* Maximal length of mqueue name */
  67 #define MQ_NAMELEN              (NAME_MAX + 1)
  68
  69 /* Default size of the message */
  70 #define MQ_DEF_MSGSIZE          1024
  71
  72 /* Size/bits and index of reserved queue */
  73 #define MQ_PQSIZE               32
  74 #define MQ_PQRESQ               0
  75
  76 /* Structure of the message queue */
  77 struct mqueue {
  78         char                    mq_name[MQ_NAMELEN];
  79         struct lock             mq_mtx;
  80         int                     mq_send_cv;     /* Condition variables for tsleep() */
  81         int                     mq_recv_cv;
  82         struct mq_attr          mq_attrib;
  83         /* Notification */
  84         struct kqinfo           mq_rkq;
  85         struct kqinfo           mq_wkq;
  86         struct sigevent         mq_sig_notify;
  87         struct proc *           mq_notify_proc;
  88         /* Permissions */
  89         mode_t                  mq_mode;
  90         uid_t                   mq_euid;
  91         gid_t                   mq_egid;
  92         /*
  93          * Reference counter, heads of the message queue
  94          *
  95          * Every message queue has `MQ_PQSIZE' priority queues that guarantee
  96          * constant-time insertion of messages. If `mq_prio_max' is increased
  97          * via sysctl, then the reserved queue (MQ_PQRESQ) is used which
  98          * performs linear insertion.
  99          */
 100         u_int                   mq_refcnt;
 101         TAILQ_HEAD(, mq_msg)    mq_head[1 + MQ_PQSIZE];
 102         uint32_t                mq_bitmap;
 103         /* Entry of the global list */
 104         LIST_ENTRY(mqueue)      mq_list;
 105         struct timespec         mq_atime;
 106         struct timespec         mq_mtime;
 107         struct timespec         mq_btime;
 108 };
 109
 110 /* Structure of the message */
 111 struct mq_msg {
 112         TAILQ_ENTRY(mq_msg)     msg_queue;
 113         size_t                  msg_len;
 114         u_int                   msg_prio;
 115         int8_t                  msg_ptr[1];
 116 };
 117
 118 /* Prototypes */
 119 void    mqueue_sysinit(void);
 120 int     abstimeout2timo(struct timespec *, int *);
 121 int     mq_send1(struct lwp *, mqd_t, const char *, size_t, unsigned, struct timespec *);
 122 int     mq_receive1(struct lwp *, mqd_t, void *, size_t, unsigned *, struct timespec *,
 123     ssize_t *);
 124
 125 #endif  /* _KERNEL || _KERNEL_STRUCTURES */
 126
 127 #endif  /* _SYS_MQUEUE_H_ */
 128