freebsd-nq/usr.sbin/pwd_mkdb/pwd_mkdb.8

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.\"	@(#)pwd_mkdb.8	8.1 (Berkeley) 6/6/93
.\" $FreeBSD$
.\"
.Dd April 30, 2018
.Dt PWD_MKDB 8
.Os
.Sh NAME
.Nm pwd_mkdb
.Nd "generate the password databases"
.Sh SYNOPSIS
.Nm
.Op Fl BCiLNp
.Op Fl d Ar directory
.Op Fl s Ar cachesize
.Op Fl u Ar username
.Ar file
.Sh DESCRIPTION
The
.Nm
utility creates
.Xr db 3
style secure and insecure databases for the specified file.
These databases are then installed into
.Pa /etc/spwd.db
and
.Pa /etc/pwd.db
respectively.
The file is installed into
.Pa /etc/master.passwd .
The file must be in the correct format (see
.Xr passwd 5 ) .
It is important to note that the format used in this system is
different from the historic Version 7 style format.
.Pp
The options are as follows:
.Bl -tag -width flag
.It Fl C
Check if the password file is in the correct format.
Do not
change, add, or remove any files.
.It Fl N
Tell
.Nm
to exit with an error if it cannot obtain a lock on the file.
By default,
we block waiting for a lock on the source file.
The lock is held through
the rebuilding of the database.
.It Fl p
Create a Version 7 style password file and install it into
.Pa /etc/passwd .
.It Fl i
Ignore locking failure of the
.Pa master.passwd
file.
This option is intended to be used to build password files in
the release process over NFS where no contention can happen.
A non-default directory must also be specified with the
.Fl d
option for locking to be ignored.
Other use of this option is strongly discouraged.
.It Fl d Ar directory
Store databases into specified destination directory instead of
.Pa /etc .
.It Fl u Ar username
Only update the record for the specified user.
Utilities that
operate on a single user can use this option to avoid the
overhead of rebuilding the entire database.
.It Fl s Ar cachesize
Specify in megabytes the size of the memory cache used by the
hashing library.
On systems with a large user base, a small cache
size can lead to prohibitively long database file rebuild times.
As a rough guide, the memory usage of
.Nm
in megabytes will be a little bit more than twice the figure
specified here.
The default is 2 megabytes.
.El
.Pp
The two databases differ in that the secure version contains the user's
encrypted password and the insecure version has an asterisk (``*'')
.Pp
The databases are used by the C library password routines (see
.Xr getpwent 3 ) .
.Pp
The following options affected the generation of legacy entries,
and are now deprecated.
.Bl -tag -width flag
.It Fl B
Store data in big-endian format.
.It Fl L
Store data in little-endian format.
.El
.Pp
The
.Nm
utility exits zero on success, non-zero on failure.
.Sh ENVIRONMENT
If the
.Ev PW_SCAN_BIG_IDS
environment variable is set,
.Nm
will suppress the warning messages that are
normally generated for large user and group IDs.
Such IDs can cause serious problems with software
that makes assumptions about the values of IDs.
.Sh FILES
.Bl -tag -width Pa -compact
.It Pa /etc/pwd.db
The insecure password database file.
.It Pa /etc/pwd.db.tmp
A temporary file.
.It Pa /etc/spwd.db
The secure password database file.
.It Pa /etc/spwd.db.tmp
A temporary file.
.It Pa /etc/master.passwd
The current password file.
.It Pa /etc/passwd
A Version 7 format password file.
.El
.Sh EXAMPLES
Regenerate the password database after manually editing or replacing
the password file:
.Bd -literal -offset -indent
/usr/sbin/pwd_mkdb -p /etc/master.passwd
.Ed
.Sh COMPATIBILITY
Previous versions of the system had a program similar to
.Nm ,
.Xr mkpasswd 8 ,
which built
.Xr dbm 3
style databases for the password file but depended on the calling programs
to install them.
The program was renamed in order that previous users of the program
not be surprised by the changes in functionality.
.Sh SEE ALSO
.Xr chpass 1 ,
.Xr passwd 1 ,
.Xr db 3 ,
.Xr getpwent 3 ,
.Xr passwd 5 ,
.Xr vipw 8
.Sh BUGS
Because of the necessity for atomic update of the password files,
.Nm
uses
.Xr rename 2
to install them.
This, however, requires that the file specified on the command line live
on the same file system as the
.Pa /etc
directory.
.Pp
There are the obvious races with multiple people running
.Nm
on different password files at the same time.
The front-ends to
.Nm ,
.Xr chpass 1 ,
.Xr passwd 1
and
.Xr vipw 8 ,
handle the locking necessary to avoid this problem.