367 lines
13 KiB
Groff
367 lines
13 KiB
Groff
.\" Copyright (c) 1996 David Nugent <davidn@blaze.net.au>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, is permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice immediately at the beginning of the file, without modification,
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.\" this list of conditions, and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. This work was done expressly for inclusion into FreeBSD. Other use
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.\" is permitted provided this notation is included.
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.\" 4. Absolutely no warranty of function or purpose is made by the author
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.\" David Nugent.
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.\" 5. Modifications may be freely made to this file providing the above
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.\" conditions are met.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 22, 1996
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.Dt LOGIN.CONF 5
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.Os FreeBSD
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.Sh NAME
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.Nm login.conf
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.Nd login class capability database
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.Sh SYNOPSIS
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.Pa /etc/login.conf ,
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.Pa ~/.login_conf
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.Sh DESCRIPTION
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.Nm login.conf
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contains various attributes and capabilities of login classes.
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A login class (an optional annotation against each record in the user
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account database,
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.Pa /etc/master.passwd )
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determines session accounting, resource limits and user environment settings.
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It is used by various programs in the system to set up a user's login
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environment and to enforce policy, accounting and administrative restrictions.
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It also provides the means by which users are able to be
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authenticated to the system and the types of authentication available.
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.Pp
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A special record "default" in the system user class capability database
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.Pa /etc/login.conf
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is used automatically for any
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non-root user without a valid login class in
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.Pa /etc/master.passwd .
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A user with a uid of 0 without a valid login class will use the record
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"root" if it exists, or "default" if not.
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.Pp
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In FreeBSD, users may individually create a file called
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.Pa .login_conf
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in their home directory using the same format, consisting of a single
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entry with a record id of "me".
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If present, this file is used by
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.Xr login 1
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to set user-defined environment settings which override those specified
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in the system login capabilities database.
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Only a subset of login capabilities may be overridden, typically those
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which do not involve authentication, resource limits and accounting.
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.Pp
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Records in a class capabilities database consist of a number of
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colon-separated fields.
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The first entry for each record gives one or more names that a record is
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to be known by, each separated by a '|' character.
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The first name is the most common abbreviation.
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The last name given should be a long name that is more descriptive
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of the capability entry, and all others are synonyms.
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All names but the last should be in lower case and contain no blanks;
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the last name may contain upper case characters and blanks for
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readability.
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.Pp
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See
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.Xr getcap 3
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for a more in-depth description of the format of a capability database.
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.Sh CAPABILITIES
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Fields within each record in the database follow the
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.Xr getcap 3
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conventions for boolean, type string
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.Ql \&=
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and type numeric
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.Ql \&# ,
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although type numeric is depreciated in favour of the string format and
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either form is accepted for a numeric datum.
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Values fall into the following categories:
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.Bl -tag -width "program"
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.It file
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Path name to a data file
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.It program
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Path name to an executable file
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.It list
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A list of values (or pairs of values) separated by commas or spaces
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.It path
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A space or comma separated list of path names, following the usual csh
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conventions (leading tilde with and without username being expanded to
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home directories etc.)
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.It number
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A numeric value, either decimal (default), hexadecimal (with leading 0x),
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or octal (with a leading 0).
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With a numeric type, only one numeric value is allowed.
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Numeric types may also be specified in string format (ie. the capability
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tag being delimited from the value by '=' instead of '#').
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Whichever method is used, then all records in the database must use the
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same method to allow values to be correctly overridden in interpolated
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records.
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.It size
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A number which expresses a size.
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The default interpretation of a value is the number of bytes, but a
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suffix may specify alternate units:
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.Bl -tag -offset indent -compact -width xxxx
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.It b
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explicitly selects 512-byte blocks
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.It k
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selects kilobytes (1024 bytes)
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.It m
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specifies a multiplier of 1 megabyte (1048576 bytes),
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.It g
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specifies units of gigabytes, and
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.It t
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represents terabytes.
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.El
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A size value is a numeric quantity and case of the suffix is not significant.
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Concatenated values are added together.
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.It time
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A period of time, by default in seconds.
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A prefix may specify a different unit:
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.Bl -tag -offset indent -compact -width xxxx
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.It y
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indicates the number of 365 day years,
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.It w
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indicates the number of weeks,
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.It d
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the number of days,
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.It h
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the number of hours,
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.It m
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the number of minutes, and
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.It s
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the number of seconds.
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.El
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Concatenated values are added together.
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For example, 2 hours and 40 minutes may be written either as
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9600s, 160m or 2h40m.
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.El
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.Pp
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The usual convention to interpolate capability entries using the special
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.Em tc=value
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notation may be used.
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.Pp
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.Sh RESOURCE LIMITS
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.Bl -column coredumpsize indent indent
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.Sy Name Type Notes Description
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.It cputime time CPU usage limit.
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.It filesize size Maximum file size limit.
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.It datasize size Maximum data size limit.
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.It stacksize size Maximum stack size limit.
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.It coredumpsize size Maximum coredump size limit.
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.It memoryuse size Maximum of core memory use size limit.
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.It memorylocked size Maximum locked in core memory size limit.
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.It maxproc number Maximum number of processes.
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.It openfiles number Maximum number of open files per process.
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.El
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.Pp
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These resource limit entries actually specify both the maximum
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and current limits (see
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.Xr getrlimit 2 ).
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The current (soft) limit is the one normally used, although the user is permitted
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to increase the current limit to the maximum (hard) limit.
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The maximum and current limits may be specified individually by appending a
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-max or -cur to the capability name.
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.Pp
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.Sh ENVIRONMENT
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.Bl -column ignorenologin indent xbinxxusrxbin
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.Sy Name Type Notes Description
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.It charset string Set $MM_CHARSET environment variable to the specified
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value.
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.It hushlogin bool false Same as having a ~/.hushlogin file.
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.It ignorenologin bool false Login not prevented by nologin.
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.It lang string Set $LANG environment variable to the specified value.
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.It manpath path Default search path for manpages.
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.It nologin file If the file exists it will be displayed and
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the login session will be terminated.
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.It path path /bin /usr/bin Default search path.
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.It priority number Initial priority (nice) level.
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.It requirehome bool false Require a valid home directory to login.
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.It setenv list A comma-separated list of environment variables and
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values to which they are to be set.
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.It shell prog Session shell to execute rather than the
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shell specified in the passwd file. The SHELL environment variable will
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contain the shell specified in the password file.
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.It term string su Default terminal type if not able to determine from
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other means.
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.It timezone string Default value of $TZ environment variable.
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.It umask number 022 Initial umask. Should always have a leading 0 to
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ensure octal interpretation.
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.It welcome file /etc/motd File containing welcome message.
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.El
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.Pp
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.Sh AUTHENTICATION
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.Bl -column minpasswordlen indent indent
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.Sy Name Type Notes Description
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.It minpasswordlen number 6 The minimum length a local password may be.
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.\" .It approve program Program to approve login.
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.It copyright file File containing additional copyright information
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.\".It widepasswords bool false Use the wide password format. The wide password
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.\" format allows up to 128 significant characters in the password.
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.It host.allow list List of remote host wildcards from which users in
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the class may access.
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.It host.deny list List of remote host wildcards from which users in
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the class may not access.
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.It times.allow list List of time periods during which
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logins are allowed.
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.It times.deny list List of time periods during which logins are
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disallowed.
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.It ttys.allow list List of ttys and ttygroups which users
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in the class may use for access.
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.It ttys.deny list List of ttys and ttygroups which users
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in the class may not use for access.
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.El
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.Pp
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These fields are intended to be used by
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.Xr passwd 1
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and other programs in the login authentication system.
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.Pp
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Capabilities that set environment variables are scanned for both
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.Ql \&~
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and
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.Ql \&$
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characters, which are substituted for a user's home directory and name
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respectively.
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To pass these characters literally into the environment variable, escape
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the character by preceding it with a backslash '\\'.
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.Pp
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The
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.Em host.allow
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and
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.Em host.deny
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entries are comma separated lists used for checking remote access to the system,
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and consist of a list of hostnames and/or IP addresses against which remote
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network logins are checked.
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Items in these lists may contain wildcards in the form used by shell programs
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for wildcard matching (See
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.Xr fnmatch 3
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for details on the implementation).
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The check on hosts is made against both the remote system's Internet address
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and hostname (if available).
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If both lists are empty or not specified, then logins from any remote host
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are allowed.
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If host.allow contains one or more hosts, then only remote systems matching
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any of the items in that list are allowed to log in.
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If host.deny contains one or more hosts, then a login from any matching hosts
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will be disallowed.
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.Pp
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The
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.Em times.allow
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and
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.Em times.deny
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entries consist of a comma-separated list of time periods during which the users
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in a class are allowed to be logged in.
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These are expressed as one or more day codes followed by a start and end times
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expressed in 24 hour format, separated by a hyphen or dash.
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For example, MoThSa0200-1300 translates to Monday, Thursday and Saturday between
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the hours of 2 am and 1 p.m..
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If both of these time lists are empty, users in the class are allowed access at
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any time.
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If
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.Em times.allow
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is specified, then logins are only allowed during the periods given.
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If
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.Em times.deny
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is specified, then logins are denied during the periods given, regardless of whether
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one of the periods specified in
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.Em times.allow
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applies.
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.Pp
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Note that
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.Xr login 1
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enforces only that the actual login falls within periods allowed by these entries.
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Further enforcement over the life of a session requires a separate daemon to
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monitor transitions from an allowed period to a non-allowed one.
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.Pp
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The
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.Em ttys.allow
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and
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.Em ttys.deny
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entries contain a comma-separated list of tty devices (without the /dev/ prefix)
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that a user in a class may use to access the system, and/or a list of ttygroups
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(See
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.Xr getttyent 3
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and
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.Xr ttys 5
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for information on ttygroups).
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If neither entry exists, then the choice of login device used by the user is
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unrestricted.
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If only
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.Em ttys.allow
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is specified, then the user is restricted only to ttys in the given
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group or device list.
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If only
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.Em ttys.deny
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is specified, then the user is prevented from using the specified devices or
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devices in the group.
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If both lists are given and are non-empty, the user is restricted to those
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devices allowed by ttys.allow that are not available by ttys.deny.
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.Sh ACCOUNTING LIMITS
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.Bl -column host.accounted indent indent
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.Sy Name Type Notes Description
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.It accounted bool false Enable session time accounting for all users
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in this class.
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.It autodelete time Time after expiry when account is auto-deleted.
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.It bootfull bool false Enable 'boot only if ttygroup is full' strategy
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when terminating sessions.
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.It daytime time Maximum login time per day.
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.It expireperiod time Time for expiry allocation.
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.It graceexpire time Grace days for expired account.
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.It gracetime time Additional grace login time allowed.
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.It host.accounted list List of remote host wildcards from which
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login sessions will be accounted.
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.It host.exempt list List of remote host wildcards from which
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login session accounting is exempted.
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.It idletime time Maximum idle time before logout.
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.It monthtime time Maximum login time per month.
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.It passwordtime time Used by
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.Xr passwd 1
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to set next password expiry date.
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.It refreshtime time New time allowed on account refresh.
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.It refreshperiod str How often account time is refreshed.
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.It sessiontime time Maximum login time per session.
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.It sessionlimit number Maximum number of concurrent
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login sessions on ttys in any group.
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.It ttys.accounted list List of ttys and ttygroups for which
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login accounting is active.
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.It ttys.exempt list List of ttys and ttygroups for which login accounting
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is exempt.
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.It warnexpire time Advance notice for pending account expiry.
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.It warnpassword time Advance notice for pending password expiry.
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.It warntime time Advance notice for pending out-of-time.
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.It weektime time Maximum login time per week.
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.El
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.Pp
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These fields are used by the time accounting system, which regulates,
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controls and records user login access.
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.Pp
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The
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.Em ttys.accounted
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and
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.Em ttys.exempt
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fields operate in a similar manner to
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.Em ttys.allow
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and
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.Em ttys.deny
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as explained
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above.
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Similarly with the
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.Em host.accounted
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and
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.Em host.exempt
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lists.
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.Sh SEE ALSO
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.Xr login 1 ,
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.Xr getcap 3 ,
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.Xr getttyent 3 ,
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.Xr login_cap 3 ,
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.Xr login_class 3 ,
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.Xr passwd 5 ,
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.Xr ttys 5
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