--- /dev/null
+.\" $NetBSD: msgctl.2,v 1.1 1995/10/16 23:49:15 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt MSGCTL 2
+.Os NetBSD
+.Sh NAME
+.Nm msgctl
+.Nd message control operations
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/msg.h>
+.Ft int
+.Fn msgctl "int msqid" "int cmd" "struct msqid_ds *buf"
+.Sh DESCRIPTION
+The
+.Fn msgctl
+system call performs some control operations on the message queue specified
+by
+.Fa msqid .
+
+Each message queue has a data structure associated with it, parts of which
+may be altered by
+.Fn msgctl
+and parts of which determine the actions of
+.Fn msgctl .
+The data structure is defined in
+.Aq Pa sys/msg.h
+and contains (amongst others) the following members:
+.Bd -literal
+struct msqid_ds {
+ struct ipc_perm msg_perm; /* msg queue permission bits */
+ u_long msg_cbytes; /* # of bytes in use on the queue */
+ u_long msg_qnum; /* # of msgs in the queue */
+ u_long msg_qbytes; /* max # of bytes on the queue */
+ pid_t msg_lspid; /* pid of last msgsnd() */
+ pid_t msg_lrpid; /* pid of last msgrcv() */
+ time_t msg_stime; /* time of last msgsnd() */
+ time_t msg_rtime; /* time of last msgrcv() */
+ time_t msg_ctime; /* time of last msgctl() */
+};
+.Ed
+
+The
+.Bf -literal
+ipc_perm
+.Ef
+structure used inside the
+.Bf -literal
+shmid_ds
+.Ef
+structure is defined in
+.Aq Pa sys/ipc.h
+and looks like this:
+.Bd -literal
+struct ipc_perm {
+ ushort cuid; /* creator user id */
+ ushort cgid; /* creator group id */
+ ushort uid; /* user id */
+ ushort gid; /* group id */
+ ushort mode; /* permission (9 bits, see chmod(2)) */
+ ushort seq; /* sequence # (to generate unique id) */
+ key_t key; /* user specified msg/sem/shm key */
+};
+.Ed
+
+The operation to be performed by
+.Fn msgctl
+is specified in
+.Fa cmd
+and is one of:
+.Bl -tag -width IPC_RMIDX
+.It Dv IPC_STAT
+Gather information about the message queue and place it in the
+structure pointed to by
+.Fa buf .
+.It Dv IPC_SET
+Set the value of the
+.Va msg_perm.uid ,
+.Va msg_perm.gid ,
+.Va msg_perm.mode
+and
+.Va msg_qbytes
+fields in the structure associated with
+.Fa msqid .
+The values are taken from the corresponding fields in the structure
+pointed to by
+.Fa buf .
+This operation can only be executed by the super-user, or a process that
+has an effective user id equal to either
+.Va msg_perm.cuid
+or
+.Va msg_perm.uid
+in the data structure associated with the message queue.
+The value of
+.Va msg_qbytes
+can only be increased by the super-user. Values for
+.Va msg_qbytes
+that exceed the system limit (MSGMNB from
+.Aq Pa sys/msg.h )
+are silently truncated to that limit.
+
+.It Dv IPC_RMID
+Remove the message queue specified by
+.Fa msqid
+and destroy the data associated with it. Only the super-user or a process
+with an effective uid equal to the
+.Va msg_perm.cuid
+or
+.Va msg_perm.uid
+values in the data structure associated with the queue can do this.
+.El
+
+The permission to read from or write to a message queue (see
+.Xr msgsnd 2
+and
+.Xr msgrcv 2 )
+is determined by the
+.Va msg_perm.mode
+field in the same way as is
+done with files (see
+.Xr chmod 2 ),
+but the effective uid can match either the
+.Va msg_perm.cuid
+field or the
+.Va msg_perm.uid
+field, and the
+effective gid can match either
+.Va msg_perm.cgid
+or
+.Va msg_perm.gid .
+.Sh RETURN VALUES
+Upon successful completion, a value of 0 is returned. Otherwise, -1 is
+returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Fn msgctl
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EPERM
+.Fa cmd
+is equal to IPC_SET or IPC_RMID and the caller is not the super-user, nor does
+the effective uid match either the
+.Va msg_perm.uid
+or
+.Va msg_perm.cuid
+fields of the data structure associated with the message queue.
+
+An attempt is made to increase the value of
+.Va msg_qbytes
+through IPC_SET
+but the caller is not the super-user.
+.It Bq Er EACCESS
+The command is IPC_STAT
+and the caller has no read permission for this message queue.
+.It Bq Er EINVAL
+.Fa msqid
+is not a valid message queue identifier.
+
+.Va cmd
+is not a valid command.
+.It Bq Er EFAULT
+.Fa buf
+specifies an invalid address.
+.El
+.Sh SEE ALSO
+.Xr msgsnd 2 ,
+.Xr msgrcv 2 ,
+.Xr msgget 2
+.Sh HISTORY
+Message queues appeared in the first release of AT&T Unix System V.
--- /dev/null
+.\" $NetBSD: msgget.2,v 1.1 1995/10/16 23:49:19 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt MSGGET 2
+.Os NetBSD
+.Sh NAME
+.Nm msgget
+.Nd get message queue
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/msg.h>
+.Ft int
+.Fn msgget "key_t key" "int msgflg"
+.Sh DESCRIPTION
+.Fn msgget
+returns the message queue identifier associated with
+.Fa key .
+A message queue identifier is a unique integer greater than zero.
+
+A message queue is created if either
+.Fa key
+is equal to IPC_PRIVATE, or
+.Fa key
+does not have a message queue identifier associated with it, and the IPC_CREAT
+bit is set in
+.Fa msgflg.
+
+If a new message queue is created, the data structure associated with it (the
+.Va msqid_ds
+structure, see
+.Xr msgctl 2 )
+is initialized as follows:
+.Bl -bullet
+.It
+.Va msg_perm.cuid
+and
+.Va msg_perm.uid
+are set to the effective uid of the calling process.
+.It
+.Va msg_perm.gid
+and
+.Va msg_perm.cgid
+are set to the effective gid of the calling process.
+.It
+.Va msg_perm.mode
+is set to the lower 9 bits of
+.Fa msgflg .
+.It
+.Va msg_cbytes ,
+.Va msg_qnum ,
+.Va msg_lspid ,
+.Va msg_lrpid ,
+.Va msg_rtime ,
+and
+.Va msg_stime
+are set to 0
+.It
+.Va msg_qbytes
+is set to the system wide maximum value for the number of bytes in a queue
+(MSGMNB).
+.It
+.Va msg_ctime
+is set to the current time.
+.El
+.Sh RETURN VALUES
+Upon successful completion a positive message queue identifier is returned.
+Otherwise, -1 is returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er EACESS
+A message queue is already associated with
+.Fa key
+and the caller has no permission to access it.
+.It Bq Er EEXIST
+Both IPC_CREAT and IPC_EXCL are set in
+.Fa msgflg ,
+and a message queue is already associated with
+.Fa key .
+.It Bq Er ENOSPC
+A new message queue could not be created because the system limit for
+the number of message queues has been reached.
+.It Bq Er ENOENT
+IPC_CREAT was not set in
+.Fa msgflg
+and no message queue associated with
+.Fa key
+was found.
+.El
+.Sh SEE ALSO
+.Xr msgctl 2 ,
+.Xr msgrcv 2 ,
+.Xr msgsnd 2
+.Sh HISTORY
+Message queues appeared in the first release of AT&T Unix System V.
--- /dev/null
+.\" $NetBSD: msgrcv.2,v 1.1 1995/10/16 23:49:20 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt MSGRCV 2
+.Os NetBSD
+.Sh NAME
+.Nm msgrcv
+.Nd receive a message from a message queue
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/msg.h>
+.Ft int
+.Fn msgrcv "int msqid" "void *msgp" "size_t msgsz" "long msgtyp" "int msgflg"
+.Sh DESCRIPTION
+The
+.Fn msgrcv
+function receives a message from the message queue specified in
+.Fa msqid ,
+and places it into the structure pointed to by
+.Fa msgp .
+This structure should consist of the following members:
+.Bd -literal
+ long mtype; /* message type */
+ char mtext[1]; /* body of message */
+.Ed
+
+.Va mtype
+is an integer greater than 0 that can be used for selecting messages,
+.Va mtext
+is an array of bytes, with a size up to that of the system limit (MSGMAX).
+
+The value of
+.Fa msgtyp
+has one of the following meanings:
+.Bl -bullet
+.It
+.Fa msgtyp
+is greater than 0. The first message of type
+.Fa msgtyp
+will be received.
+.It
+.Fa msgtyp
+is equal to 0. The first message on the queue will be received.
+.It
+.Fa msgtyp
+is less than 0. The first message of the lowest message type that is
+less than or equal to the absolute value of
+.Fa msgtyp
+will be received.
+.El
+
+.Fa msgsz
+specifies the maximum length of the requested message. If the received
+message has a length greater than
+.Fa msgsz
+it will be silently truncated if the MSG_NOERROR flag is set in
+.Fa msgflg ,
+otherwise an error will be returned.
+
+If no matching message is present on the message queue specified by
+.Fa msqid ,
+the behaviour of
+.Fn msgrcv
+depends on whether the IPC_NOWAIT flag is set in
+.Fa msgflg
+or not. If IPC_NOWAIT is set,
+.Fn msgrcv
+will immediately return a value of -1, and set
+.Va errno
+to EAGAIN. If IPC_NOWAIT is not set, the calling process will be blocked
+until:
+.Bl -bullet
+.It
+A message of the requested type becomes available on the message queue.
+.It
+The message queue is removed, in which case -1 will be returned, and
+.Va errno
+set to EINVAL.
+.It
+A signal is received and caught. -1 is returned, and
+.Va errno
+set to EINTR.
+.El
+
+If a message is successfully received, the data structure associated with
+.Fa msqid
+is updated as follows:
+.Bl -bullet
+.It
+.Va msg_cbytes
+is decremented by the size of the message.
+.It
+.Va msg_lrpid
+is set to the pid of the caller.
+.It
+.Va msg_lrtime
+is set to the current time.
+.It
+.Va msg_qnum
+is decremented by 1.
+.Sh RETURN VALUES
+Upon successful completion,
+.Fn msgrcv
+returns the number of bytes received into the
+.Va mtext
+field of the structure pointed to by
+.Fa msgp .
+Otherwise, -1 is returned, and
+.Va errno
+set to indicate the error.
+.Sh ERRORS
+.Fn msgrcv
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+.Fa msqid
+is not a valid message queue identifier
+
+The message queue was removed while
+.Fn msgrcv
+was waiting for a message of the requested type to become available on it.
+
+.Fa msgsz
+is less than 0.
+.It Bq Er E2BIG
+A matching message was received, but its size was greater than
+.Fa msgsz
+and the MSG_NOERROR flag was not set in
+.Fa msgflg .
+.It Bq Er EACCESS
+The calling process does not have read access to the message queue.
+.It Bq Er EFAULT
+.Fa msgp
+points to an invalid address.
+.It Bq Er EINTR
+The system call was interrupted by the delivery of a signal.
+.It Bq Er EAGAIN
+There is no message of the requested type available on the message queue,
+and IPC_NOWAIT is set in
+.Fa msgflg .
+.Sh SEE ALSO
+.Xr msgsnd 2 ,
+.Xr msgctl 2 ,
+.Xr msgget 2
+.Sh BUGS
+NetBSD does not define the EIDRM error value, which should be used in
+the case of a removed message queue, nor the ENOMSG value, which
+should be used when no suitable message is available and IPC_NOWAIT
+is set.
+.Sh HISTORY
+Message queues appeared in the first release of AT&T Unix System V.
--- /dev/null
+.\" $NetBSD: msgsnd.2,v 1.1 1995/10/16 23:49:24 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt MSGSND 2
+.Os NetBSD
+.Sh NAME
+.Nm msgsnd
+.Nd send a message to a message queue
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/msg.h>
+.Ft int
+.Fn msgsnd "int msqid" "void *msgp" "size_t msgsz" "int msgflg"
+.Sh DESCRIPTION
+The
+.Fn msgsnd
+function sends a message from the message queue specified in
+.Fa msqid .
+.Fa msgp
+points to a structuer containing the message. This structure should
+consist of the following members:
+.Bd -literal
+ long mtype; /* message type */
+ char mtext[1]; /* body of message */
+.Ed
+
+.Va mtype
+is an integer greater than 0 that can be used for selecting messages (see
+.Xr msgrcv 2 ) ,
+.Va mtext
+is an array of bytes, with a size up to that of the system limit (MSGMAX).
+
+If the number of bytes already on the message queue plus
+.Fa msgsz
+is bigger than the maximum number of bytes on the message queue (
+.Va msg_qbytes ,
+see
+.Xr msgctl 2 ) ,
+or the number of messages on all queues system-wide is already equal to
+the system limit,
+.Fa msgflg
+determines the action of
+.Fn msgsnd .
+If
+.Fa msgflg
+has IPC_NOWAIT mask set in it, the call will return immediately. If
+.Fa msgflg
+does not have IPC_NOWAIT set in it, the call will block until:
+.Bl -bullet
+.It
+The condition which caused the call to block does no longer exist.
+The message will be sent.
+.It
+The messag queue is removed, in which case -1 will be returned, and
+.Va errno
+is set to EINVAL.
+.It
+The caller catches a signal. The call returns with
+.Va errno
+set to EINTR.
+.El
+
+After a successful call, the data structure associated with the message
+queue is updated in the following way:
+.Bl -bullet
+.It
+.Va msg_cbytes
+is incremented by the size of the message.
+.It
+.Va msg_qnum
+is incremented by 1.
+.It
+.Va msg_lspid
+is set to the pid of the calling process.
+.It
+.Va msg_stime
+is set to the current time.
+.El
+.Sh RETURN VALUES
+Upon successful completion, 0 is returned. Otherwise, -1 is returned and
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Fn msgsnd
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+.Fa msqid
+is not a valid message queue identifier
+
+The message queue was removed while
+.Fn msgsnd
+was waiting for a resource to become available in order to deliver the
+message.
+
+.Fa msgsz
+is less than 0, or greater than
+.Va msg_qbytes .
+.It Bq Er EACCESS
+The calling process does not have write access to the message queue.
+.It Bq Er EAGAIN
+There was no space for this message either on the queue, or in the whole
+system, and IPC_NOWAIT was set in
+.Fa msgflg .
+.It Bq Er EFAULT
+.Fa msgp
+points to an invalid address.
+.It Bq Er EINTR
+The system call was interrupted by the delivery of a signal.
+.El
+.Sh BUGS
+NetBSD does not define the EIDRM error value, which should be used
+in the case of a removed message queue.
+.Sh HISTORY
+Message queues appeared in the first release of AT&T Unix System V.
--- /dev/null
+.\" $NetBSD: semctl.2,v 1.1 1995/10/16 23:49:26 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt SEMCTL 2
+.Os NetBSD
+.Sh NAME
+.Nm semctl
+.Nd semaphore control operations
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/sem.h>
+.Ft int
+.Fn semctl "int semid" "int semnum" "int cmd" "union semun arg"
+.Sh DESCRIPTION
+The
+.Fn semctl
+system call provides a number of control operations on the semaphore specified
+by
+.Fa semnum
+and
+.Fa semid .
+The operation to be performed is specified in
+.Fa cmd
+(see below).
+.Fa arg
+is a union of the following fields:
+.Bd -literal
+ int val; /* value for SETVAL */
+ struct semid_ds *buf; /* buffer for IPC_{STAT,SET} */
+ u_short *array; /* array for GETALL & SETALL */
+.Ed
+
+The
+.Bf -literal
+semid_ds
+.Ef
+structure used in the IPC_SET and IPC_STAT commands is defined
+as follows in
+.Aq Pa sys/sem.h :
+.Bd -literal
+struct semid_ds {
+ struct ipc_perm sem_perm; /* operation permissions */
+ struct sem *sem_base; /* semaphore set */
+ u_short sem_nsems; /* number of sems in set */
+ time_t sem_otime; /* last operation time */
+ time_t sem_ctime; /* last change time */
+};
+.Ed
+
+The
+.Bf -literal
+ipc_perm
+.Ef
+structure used inside the
+.Bf -literal
+semid_ds
+.Ef
+structure is defined in
+.Aq Pa sys/ipc.h
+and looks like this:
+.Bd -literal
+struct ipc_perm {
+ ushort cuid; /* creator user id */
+ ushort cgid; /* creator group id */
+ ushort uid; /* user id */
+ ushort gid; /* group id */
+ ushort mode; /* r/w permission (see chmod(2)) */
+ ushort seq; /* sequence # (to generate unique msg/sem/shm id) */
+ key_t key; /* user specified msg/sem/shm key */
+};
+.Ed
+
+.Fn semctl
+provides the following operations:
+.Bl -tag -width IPC_RMIDX
+.It Dv GETVAL
+Return the value of the semaphore.
+.It Dv SETVAL
+Set the value of the semaphore to
+.Va arg.val .
+.It Dv GETPID
+Return the pid of the last process that did an operation on this semaphore.
+.It Dv GETNCNT
+Return the number of processes waiting to acquire the semaphore.
+.It Dv GETZCNT
+Return the number of processes waiting for the value of the semaphore to
+reach 0.
+.It Dv GETALL
+Return the values for all the semaphores associated with
+.Fa semid .
+.It Dv SETALL
+Set the values for all the semaphores that are associated with the semaphore
+identifier
+.Fa semid
+to the corresponding values in
+.Va arg.array .
+.It Dv IPC_STAT
+Gather statistics about a semaphore and place the information in the
+.Bf -literal
+semid_ds
+.Ef
+structure pointed to by
+.Fa arg.buf
+(see above).
+.It Dv IPC_SET
+Set the value of the
+.Va sem_perm.uid ,
+.Va sem_perm.gid
+and
+.Va sem_perm.mode
+fields in the structure associated with the semaphore.
+The values are taken from the corresponding fields in the structure
+pointed to by
+.Fa arg.buf .
+This operation can only be executed by the super-user, or a process that
+has an effective user id equal to either
+.Va sem_perm.cuid
+or
+.Va sem_perm.uid
+in the data structure associated with the message queue.
+.It Dv IPC_RMID
+Remove the semaphores associated with
+.Fa semid
+from the system and destroy the data structures associated with it. Only the
+super-user or a process with an effective uid equal to the
+.Va sem_perm.cuid
+or
+.Va sem_perm.uid
+values in the data structure associated with the semaphore can do this.
+.El
+
+The permission to read or change a message queue (see
+.Xr semop 2 )
+is determined by the
+.Va sem_perm.mode
+field in the same way as is
+done with files (see
+.Xr chmod 2 ),
+but the effective uid can match either the
+.Va sem_perm.cuid
+field or the
+.Va sem_perm.uid
+field, and the
+effective gid can match either
+.Va sem_perm.cgid
+or
+.Va sem_perm.gid .
+.Sh RETURN VALUES
+For the GETVAL, GETPID, GETNCNT and GETZCNT operations,
+.Fn semctl
+returns one of the values described above if successful. All other operations
+will make
+.Fn semctl
+return 0 if no errors occur. Otherwise -1 is returned and
+.Va errno
+set to reflect the error.
+.Sh ERRORS
+.Fn semctl
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EPERM
+.Fa cmd
+is equal to IPC_SET or IPC_RMID and the caller is not the super-user, nor does
+the effective uid match either the
+.Va sem_perm.uid
+or
+.Va sem_perm.cuid
+fields of the data structure associated with the message queue.
+.It Bq Er EACCESS
+The caller has no operation permission for this semaphore.
+.It Bq Er EINVAL
+.Fa semid
+is not a valid message semaphore identifier.
+
+.Va cmd
+is not a valid command.
+.It Bq Er EFAULT
+.Fa arg.buf
+specifies an invalid address.
+.El
+.Sh SEE ALSO
+.Xr semop 2
+.Xr semget 2
--- /dev/null
+.\" $NetBSD: semget.2,v 1.1 1995/10/16 23:49:27 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt SEMGET 2
+.Os NetBSD
+.Sh NAME
+.Nm semget
+.Nd get semaphore set
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/sem.h>
+.Ft int
+.Fn semget "key_t key" "int nsems" "int semflg"
+.Sh DESCRIPTION
+The
+.Fn semget
+system call returns the semaphore identifier associated with
+.Fa key .
+
+A new set containing
+.Fa nsems
+semaphores is created if either
+.Fa key
+is equal to IPC_PRIVATE, or
+.Fa key
+does not have a semaphore set associated with it, and the IPC_CREAT bit is
+set in
+.Fa msgflg.
+
+If a new set of semaphores is created, the data structure associated with it
+(the
+.Va semid_ds
+structure, see
+.Xr semctl 2 )
+is intialized as follows:
+.Bl -bullet
+.It
+.Va sem_perm.cuid
+and
+.Va sem_perm.uid
+are set to the effective uid of the calling process.
+.It
+.Va sem_perm.gid
+and
+.Va sem_perm.cgid
+are set to the effective gid of the calling process.
+.It
+.Va sem_perm.mode
+is set to the lower 9 bits of
+.Fa msgflg .
+.It
+.Va sem_nsems
+is set to the value of
+.Fa nsems
+.It
+.Va sem_ctime
+is set to the current time
+.It
+.Va sem_otime
+is set to 0
+.El
+.Sh RETURN VALUES
+.Fn semget
+returns a non-negative semaphore identifier if successful. Otherwise, -1
+is returned and
+.Va errno
+is set to reflect the error.
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er EACCESS
+The caller has no permission to access a semaphore set already associated with
+.Fa key.
+.It Bq Er EEXIST
+Both IPC_CREAT and IPC_EXCL are set in
+.Fa msgflg ,
+and a semaphore set is already associated with
+.Fa key .
+.It Bq Er EINVAL
+.Va nsems
+is less than 0 or greater than the system limit for the number in a semaphore
+set.
+
+A semaphore set associated with
+.Fa key
+exists, but has fewer semaphores than the number specified in
+.Fa nsems .
+.It Bq Er ENOSPC
+A new set of semaphores could not be created because the system limit
+for the number of semaphores or the number of semaphore sets has been
+reached.
+.It Bq Er ENOENT
+IPC_CREAT was not set in
+.Fa msgflg
+and no semaphore set associated with
+.Fa key
+was found.
+.El
+.Sh SEE ALSO
+.Xr semop 2
+.Xr semctl 2
--- /dev/null
+.\" $NetBSD: semop.2,v 1.1 1995/10/16 23:49:28 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt SEMOP 2
+.Os NetBSD
+.Sh NAME
+.Nm semop
+.Nd semaphore operations
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/sem.h>
+.Ft int
+.Fn semop "int semid" "struct sembuf *sops" "int nsops"
+.Sh DESCRIPTION
+.Fn semop
+provides a number of atomic operations on a set of semaphores. The semaphore
+set is specified by
+.Fa semid .
+.Fa sops
+is an array of semaphore operations,
+.Fa nsops
+is the number of operations in this array. The
+.Va sembuf
+structures in the array contain the following members:
+.Bd -literal
+ u_short sem_num; /* semaphore # */
+ short sem_op; /* semaphore operation */
+ short sem_flg; /* operation flags */
+.Ed
+
+Each operation (specified in
+.Va sem_op )
+is applied to semaphore number
+.Va sem_num
+in the set of semaphores specified by
+.Fa semid .
+The value of
+.Va sem_op
+determines the action taken in the following way:
+.Bl -bullet
+.It
+.Va sem_op
+is less than 0. The current process is blocked until the value of the
+semaphore is greater than or equal to the absolute value of
+.Va sem_op .
+The absolute value of
+.Va sem_op
+is then subtracted from the value of the semaphore, and the calling
+process continues. Negative values of
+.Va sem_op
+are thus used to enter critical regions.
+.It
+.Va sem_op
+is greater than 0. Its value is added to the value of the specified
+semaphore. This is used to leave critical regions.
+.It
+.Va sem_op
+is equal to 0. The calling process is blocked until the value of the
+specified semaphore reaches 0.
+.El
+
+The behaviour of each operation is influenced by the flags set in
+.Va sem_flg
+in the following way:
+.Bl -tag -width IPC_NOWAITX
+.It IPC_NOWAIT
+In the case where the calling process would normally block, waiting
+for a semaphore to reach a certain value, IPC_NOWAIT makes the
+call return immediately, returning a value of -1 and setting
+.Va errno
+to EAGAIN.
+.It SEM_UNDO
+Keep track of the changes that this call makes to the value of a semaphore,
+so that they can be undone when the calling process terminates. This is
+useful to prevent other processes waiting on a semaphore to block forever,
+should the process that has the semaphore locked terminate in a critical
+section.
+.El
+.Sh RETURN VALUES
+Upon successful completion, a value of 0 is returned. Otherwise, -1 is
+returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Fn semop
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+There is no semaphore associated with
+.Fa semid .
+
+The semaphore set was removed while the process was waiting for one of
+its semaphores to reach a certain value.
+
+.It Bq Er EACCESS
+The calling process has no permission to access the specified semaphore set.
+.It Bq Er E2BIG
+The value of
+.Fa nsops
+is too big. The maximum is specified in MAX_SOPS in <sys/sem.h>
+.It Bq Er EFBIG
+.Va sem_num
+in one of the sem_buf structures is less than 0, or greater than the actual
+number of semaphores in the set specified by
+.Fa semid .
+.It Bq Er ENOSPC
+SEM_UNDO was requested, and there is not enough space left in the kernel to
+store the unfo information.
+.It Bq Er EAGAIN
+The requested operation can not immediately be performed, and IPC_NOWAIT
+was set in
+.Va sem_flg .
+.It Bq Er EFAULT
+.Fa sops
+points to an illegal address.
+.Sh SEE ALSO
+.Xr semctl 2 ,
+.Xr semget 2
+.Sh BUGS
+In case of a removed semaphore identifier,
+.Va errno
+should be set to EIDRM, but NetBSD does not define this error.
--- /dev/null
+.\" $NetBSD: shmat.2,v 1.1 1995/10/16 23:49:29 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt SHMAT 2
+.Os NetBSD
+.Sh NAME
+.Nm shmat ,
+.Nm shmdt
+.Nd map/unmap shared memory
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/shm.h>
+.Ft void *
+.Fn shmat "int shmid" "void *shmaddr" "int shmflg"
+.Ft int
+.Fn shmdt "void *shmaddr"
+.Sh DESCRIPTION
+.Fn shmat
+maps the shared memory segment associated with the shared memory identifier
+.Fa shmid
+into the address space of the calling process. The address at which the
+segment is mapped is determined by the
+.Fa shmaddr
+parameter. If it is equal to 0, the system will pick an address itself.
+Otherwise, an attempt is made to map the shared memory segment at the
+address
+.Fa shmaddr
+specifies. If SHM_RND is set in
+.Fa shmflg ,
+the system will round the address down to a multiple of SHMLBA bytes
+(SHMLBA is defined in
+.Aq Pa sys/shm.h
+).
+
+A shared memory segment can be mapped read-only by specifying the
+SHM_RDONLY flag in
+.Fa shmflg .
+
+.Fn shmdt
+unmaps the shared memory segment that is currently mapped at
+.Fa shmaddr
+from the calling process' address space.
+.Fa shmaddr
+must be a value returned by a prior
+.Fn shmat
+call. A shared memory segment will remain existant until it is removed by
+a call to
+.Xr shmctl 2
+with the IPC_RMID command.
+.Sh RETURN VALUES
+.Fn shmat
+returns the address at which the shared memory segment has been mapped into
+the calling process' address space when successful,
+.Fn shmdt
+returns 0 on successful completion. Otherwise, a value of -1 is returned,
+and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Fn shmat
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EACCESS
+The calling process has no permission to access this shared memory segment.
+.It Bq Er ENOMEM
+There is not enough available data space for the calling process to
+map the shared memory segment.
+.It Bq Er EINVAL
+.Fa shmid
+is not a valid shared memory identifier.
+
+.Fa shmaddr
+specifies an illegal address.
+.It Bq Er EMFILE
+The number of shared memory segments has reached the system-wide limit.
+.El
+
+.Fn shmdt
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+.Fa shmaddr
+is not the start address of a mapped shared memory segment.
+.Sh SEE ALSO
+.Xr shmctl 2 ,
+.Xr shmget 2 ,
+.Xr mmap 2
--- /dev/null
+.\" $NetBSD: shmctl.2,v 1.1 1995/10/16 23:49:30 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt SHMCTL 2
+.Os NetBSD
+.Sh NAME
+.Nm shmctl
+.Nd shared memory control operations
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/msg.h>
+.Ft int
+.Fn shmctl "int shmid" "int cmd" "struct shmid_ds *buf"
+.Sh DESCRIPTION
+The
+.Fn shmctl
+system call performs some control operations on the shared memory area
+specified by
+.Fa shmid .
+
+Each shared memory segment has a data structure associated with it,
+parts of which may be altered by
+.Fn shmctl
+and parts of which determine the actions of
+.Fn shmctl .
+
+This structure is defined as follows in
+.Aq Pa sys/shm.h :
+.Bd -literal
+struct shmid_ds {
+ struct ipc_perm shm_perm; /* operation permissions */
+ int shm_segsz; /* size of segment in bytes */
+ pid_t shm_lpid; /* pid of last shm op */
+ pid_t shm_cpid; /* pid of creator */
+ short shm_nattch; /* # of current attaches */
+ time_t shm_atime; /* last shmat() time*/
+ time_t shm_dtime; /* last shmdt() time */
+ time_t shm_ctime; /* last change by shmctl() */
+ void *shm_internal; /* sysv stupidity */
+};
+.Ed
+The
+.Bf -literal
+ipc_perm
+.Ef
+structure used inside the
+.Bf -literal
+shmid_ds
+.Ef
+structure is defined in
+.Aq Pa sys/ipc.h
+and looks like this:
+.Bd -literal
+struct ipc_perm {
+ ushort cuid; /* creator user id */
+ ushort cgid; /* creator group id */
+ ushort uid; /* user id */
+ ushort gid; /* group id */
+ ushort mode; /* r/w permission (see chmod(2)) */
+ ushort seq; /* sequence # (to generate unique msg/sem/shm id) */
+ key_t key; /* user specified msg/sem/shm key */
+};
+.Ed
+
+The operation to be performed by
+.Fn shmctl
+is specified in
+.Fa cmd
+and is one of:
+.Bl -tag -width IPC_RMIDX
+.It Dv IPC_STAT
+Gather information about the shared memory segment and place it in the
+structure pointed to by
+.Fa buf .
+.It Dv IPC_SET
+Set the value of the
+.Va shm_perm.uid ,
+.Va shm_perm.gid
+and
+.Va shm_perm.mode
+fields in the structure associated with
+.Fa shmid .
+The values are taken from the corresponding fields in the structure
+pointed to by
+.Fa buf .
+This operation can only be executed by the super-user, or a process that
+has an effective user id equal to either
+.Va shm_perm.cuid
+or
+.Va shm_perm.uid
+in the data structure associated with the shared memory segment.
+
+.It Dv IPC_RMID
+Remove the shared memory segment specified by
+.Fa shmid
+and destroy the data associated with it. Only the super-user or a process
+with an effective uid equal to the
+.Va shm_perm.cuid
+or
+.Va shm_perm.uid
+values in the data structure associated with the queue can do this.
+.El
+
+The read and write permissions on a shared memory identifier
+are determined by the
+.Va shm_perm.mode
+field in the same way as is
+done with files (see
+.Xr chmod 2 ),
+but the effective uid can match either the
+.Va shm_perm.cuid
+field or the
+.Va shm_perm.uid
+field, and the
+effective gid can match either
+.Va shm_perm.cgid
+or
+.Va shm_perm.gid .
+.Sh RETURN VALUES
+Upon successful completion, a value of 0 is returned. Otherwise, -1 is
+returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Fn shmctl
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EPERM
+.Fa cmd
+is equal to IPC_SET or IPC_RMID and the caller is not the super-user, nor does
+the effective uid match either the
+.Va shm_perm.uid
+or
+.Va shm_perm.cuid
+fields of the data structure associated with the shared memory segment.
+
+An attempt is made to increase the value of
+.Va shm_qbytes
+through IPC_SET
+but the caller is not the super-user.
+.It Bq Er EACCESS
+The command is IPC_STAT
+and the caller has no read permission for this shared memory segment.
+.It Bq Er EINVAL
+.Fa shmid
+is not a valid shared memory segment identifier.
+
+.Va cmd
+is not a valid command.
+.It Bq Er EFAULT
+.Fa buf
+specifies an invalid address.
+.El
+.Sh SEE ALSO
+.Xr shmat 2 ,
+.Xr shmdt 2 ,
+.Xr shmget 2
--- /dev/null
+.\" $NetBSD: shmget.2,v 1.1 1995/10/16 23:49:32 jtc Exp $
+.\"
+.\" Copyright (c) 1995 Frank van der Linden
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed for the NetBSD Project
+.\" by Frank van der Linden
+.\" 4. The name of the author may not be used to endorse or promote products
+.\" derived from this software without specific prior written permission
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"/
+.Dd August 17, 1995
+.Dt SHMGET 2
+.Os NetBSD
+.Sh NAME
+.Nm shmget
+.Nd get shared memory area identifier
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/ipc.h>
+.Fd #include <sys/shm.h>
+.Ft int
+.Fn shmget "key_t key" "int size" "int shmflg"
+.Sh DESCRIPTION
+.Fn shmget
+returns the shared memory identifier associated with the key
+.Fa key .
+
+A shared memory segment is created if either
+.Fa key
+is equal to IPC_PRIVATE, or
+.Fa key
+does not have a shared memory segment identifier associated with it, and the IPC_CREAT
+bit is set in
+.Fa shmflg.
+
+If a new shared memory segment is created, the data structure associated with it (the
+.Va shmid_ds
+structure, see
+.Xr shmctl 2 )
+is initialized as follows:
+.Bl -bullet
+.It
+.Va shm_perm.cuid
+and
+.Va shm_perm.uid
+are set to the effective uid of the calling process.
+.It
+.Va shm_perm.gid
+and
+.Va shm_perm.cgid
+are set to the effective gid of the calling process.
+.It
+.Va shm_perm.mode
+is set to the lower 9 bits of
+.Fa shmflg .
+.It
+.Va shm_lpid ,
+.Va shm_nattch ,
+.Va shm_atime ,
+and
+.Va shm_dtime
+are set to 0
+.It
+.Va shm_ctime
+is set to the current time.
+.It
+.Va shm_segsz
+is set to the value of
+.Fa size .
+.El
+.Sh RETURN VALUES
+Upon successful completion a positive shared memory segment identifier is returned.
+Otherwise, -1 is returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er EACESS
+A shared memory segment is already associated with
+.Fa key
+and the caller has no permission to access it.
+.It Bq Er EEXIST
+Both IPC_CREAT and IPC_EXCL are set in
+.Fa shmflg ,
+and a shared memory segment is already associated with
+.Fa key .
+.It Bq Er ENOSPC
+A new shared memory indentifier could not be created because the system limit
+for the number of shared memory identifiers has been reached.
+.It Bq Er ENOENT
+IPC_CREAT was not set in
+.Fa shmflg
+and no shared memory segment associated with
+.Fa key
+was found.
+.It Bq Er ENOMEM
+There is not enough memory left to created a shared memory segment of the
+requested size.
+.El
+.Sh SEE ALSO
+.Xr shmctl 2 ,
+.Xr shmat 2 ,
+.Xr shmdt 2
projects / openbsd / commitdiff