cb5f7ee837
- Exit with an error if no path is specified. - Man page typo. - Error message typo. Reviewed by: kib Sponsored by: Juniper Networks, Inc. Sponsored by: Klara, Inc. MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D26376
155 lines
4.2 KiB
Groff
155 lines
4.2 KiB
Groff
.\" Copyright (c) 2019 The FreeBSD Foundation, Inc.
|
|
.\"
|
|
.\" This documentation was written by
|
|
.\" Konstantin Belousov <kib@FreeBSD.org> under sponsorship
|
|
.\" from the FreeBSD Foundation.
|
|
.\"
|
|
.\" 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.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``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 AUTHORS OR CONTRIBUTORS 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.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd March 18, 2020
|
|
.Dt POSIXSHMCONTROL 1
|
|
.Os
|
|
.Sh NAME
|
|
.Nm posixshmcontrol
|
|
.Nd Control POSIX shared memory segments
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Ar create
|
|
.Op Fl m Ar mode
|
|
.Op Pa path \&...
|
|
.Nm
|
|
.Ar rm
|
|
.Op Pa path \&...
|
|
.Nm
|
|
.Ar ls
|
|
.Op Fl h
|
|
.Op Fl n
|
|
.Nm
|
|
.Ar dump
|
|
.Op Pa path \&...
|
|
.Nm
|
|
.Ar stat
|
|
.Op Fl h
|
|
.Op Fl n
|
|
.Op Pa path \&...
|
|
.Nm
|
|
.Ar truncate
|
|
.Op Fl s Ar length
|
|
.Op Pa path \&...
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
command manipulates the named POSIX shared memory segments.
|
|
It allows inspecting existing segments, dumping their metadata or contents,
|
|
and unlinking them.
|
|
.Pp
|
|
Unlinking removes the name from the system and, when the last process
|
|
unmaps the segment and closes file descriptor pointing to the segment,
|
|
frees underlying memory.
|
|
.Pp
|
|
The number of hard links as displayed by the
|
|
.Ic stat
|
|
subcommand, is equal to the number of references to the underlying VM
|
|
object.
|
|
It is almost always equal to the number of mappings +1, except
|
|
for transient references.
|
|
.Pp
|
|
The following subcommands are provided:
|
|
.Bl -tag -width truncate
|
|
.It Ic create
|
|
Create segments with the specified paths, if not exist.
|
|
The
|
|
.Ar mode
|
|
optional numerical argument specifies initial access mode.
|
|
.It Ic rm
|
|
Unlink the paths specified.
|
|
.It Ic ls
|
|
List all linked named shared memory segments visible to the caller.
|
|
For each segment, the user and group owner, size, and path are displayed.
|
|
.It Ic dump
|
|
Output raw bytes values from the segment to standard output.
|
|
.It Ic stat
|
|
Print metadata for the specified path, in the format similar to the
|
|
.Xr stat 1
|
|
utility.
|
|
.It Ic truncate
|
|
Change the length of the segments.
|
|
Argument to the
|
|
.Fl s
|
|
option specifies new length.
|
|
The human-friendly 'k', 'm', 'g' suffixes can be used, see
|
|
.Xr expand_number 3 .
|
|
If the option is not specified, assumed length is zero.
|
|
.El
|
|
.Pp
|
|
For some commands, the following options may be provided:
|
|
.Bl -tag -width XXX
|
|
.It Fl h
|
|
If specified, requests human-readable display of size, see
|
|
.Xr humanize_number 3 .
|
|
.It Fl n
|
|
Prevent translation of owner and group into symbolic names
|
|
using name-switch services, instead the raw numeric values are printed.
|
|
.El
|
|
.Sh EXIT STATUS
|
|
.Ex -std
|
|
.Sh EXAMPLES
|
|
.Bl -bullet
|
|
.It
|
|
To show content of the shared memory segment with the path
|
|
.Pa /1 ,
|
|
use the command
|
|
.Dl "posixshmcontrol dump /1 | hexdump -C"
|
|
.It
|
|
To create a segment with the path
|
|
.Pa /2
|
|
and then enlarge it to 1M, use the sequence of commands
|
|
.Dl "posixshmcontrol create /2"
|
|
.Dl "posixshmcontrol truncate -s 1m /2"
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr hexdump 1 ,
|
|
.Xr stat 1 ,
|
|
.Xr ftruncate 2 ,
|
|
.Xr read 2 ,
|
|
.Xr shm_open 2 ,
|
|
.Xr shm_unlink 2 ,
|
|
.Xr stat 2 ,
|
|
.Xr expand_number 3 ,
|
|
.Xr humanize_number 3 ,
|
|
.Xr sysctl 3
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
command appeared in
|
|
.Fx 12.1 .
|
|
.Sh AUTHORS
|
|
The
|
|
.Nm
|
|
command and this manual page were written by
|
|
.An Konstantin Belousov Aq Mt kib@freebsd.org
|
|
under sponsorship from The
|
|
.Fx
|
|
Foundation.
|