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Diffstat (limited to 'lib/libc/gen/msgctl.3')
| -rw-r--r-- | lib/libc/gen/msgctl.3 | 209 |
1 files changed, 0 insertions, 209 deletions
diff --git a/lib/libc/gen/msgctl.3 b/lib/libc/gen/msgctl.3 deleted file mode 100644 index 130b1f2..0000000 --- a/lib/libc/gen/msgctl.3 +++ /dev/null @@ -1,209 +0,0 @@ -.\" $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. -.\" -.\" $Id$ -.\"/ -.Dd November 24, 1997 -.Dt MSGCTL 3 -.Os FreeBSD -.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 */ - struct msg *msg_first; /* first message in the queue */ - struct msg *msg_last; /* last message in the queue */ - u_long msg_cbytes; /* number of bytes in use on the queue */ - u_long msg_qnum; /* number 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() */ - long msg_pad1; - time_t msg_rtime; /* time of last msgrcv() */ - long msg_pad2; - time_t msg_ctime; /* time of last msgctl() */ - long msg_pad3; - long msg_pad4[4]; -}; -.Ed -.Pp -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 */ - ushort seq; /* sequence # (to generate unique msg/sem/shm id) */ - key_t key; /* user specified msg/sem/shm key */ -}; -.Ed -.Pp -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 3 -and -.Xr msgrcv 3 ) -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 EACCES -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 msgget 3 , -.Xr msgrcv 3 , -.Xr msgsnd 3 -.Sh HISTORY -Message queues appeared in the first release of AT&T Unix System V. |
