makeuserdb(8)

NAME
makeuserdb - Create /etc/userdb.dat

SYNOPSIS
makeuserdb
pw2userdb
vchkpw2userdb [ --vpopmailhome=dir ] [ --todir=dir ]

DESCRIPTION

These commands are used to create the /etc/userdb.dat database. makeuserdb creates /etc/userdb.dat based on the contents of /etc/userdb. /etc/userdb.dat is used by maildrop, Courier, and other applications as a substitute/complement for your system password file. The usual purpose for /etc/userdb.dat is to specify "virtual" accounts - accounts that do not have an associated login. Typically all virtual accounts share the same system userid. /etc/userdb.dat can also be used as a replacement for your system password file. Because the system password file is a text file, when there's a large number of accounts it will be significantly faster to search a binary database, instead of a text file.

The makeuserdb command creates /etc/userdb.dat based on the contents of /etc/userdb. /etc/userdb is a plain text file, or a directory. If it is a directory, the contents of all files in the directory are simply concatenated together.

makeuserdb command can be safely executed during normal system activity.

Format of /etc/userdb
/etc/userdb is a plain text file that can be created using any text editor. Blank lines are ignored. Lines that start with the # character are comments, and are also ignored. Other lines define properties of a single account, one line per account. If /etc/userdb is a directory, each file in /etc/userdb is formatted the same way. Each line takes the following format:
name<TAB>field=value|field=value

name is the account name. If Courier is configured to treat lowercase and uppercase account names as identical, name MUST contain lowercase characters only. name is followed by exactly one tab character, then a list of field/value pairs separated by vertical slashes. field is the name of the field, value is the field value. The field value itself cannot contain slashes or control characters. Fields can be specified in any order. Here are all the currently defined fields. Note that not every field is used by every application that reads /etc/userdb.dat.

uid value specifies a (possibly) unique numerical user ID for this account.

gid value specifies a (possibly) unique numerical group ID for this account.

home
    value specifies the account's home directory.

shell
    value specifies the account's default shell.

systempw
    value specifies the account's system password. See userdbpw(8) for a way to set this field.

pop3pw, esmtppw, imappw...
    value specifies a separate password used only for authenticating access via some service, such as POP3, IMAP, or anything else. If not defined, systempw is always used. This allows you to define separate passwords for each service, or always use the same password for everything, your choice.

mail
    value specifies the location of the account's Maildir mailbox. If missing, the account's Maildir is expected to be present in the default location for system accounts.

quota
    value specifies the quota for the account's Maildir. See maildirquota(8) for more information.

The uid, gid, and home fields MUST be specified. The remaining fields are optional. If missing, system defaults will be used.
=uid<TAB>name

This entry is used to specify reverse mapping from userids to names. uid specifies the system userid, name specifies the system username. name must point to another record in userdb.

/etc/userdbshadow.dat

All fields whose name ends with 'pw' will NOT copied to /etc/userdb.dat. These fields will be copied to /etc/userdbshadow.dat. makeuserdb will turn off all group and world permissions on /etc/userdbshadow.dat. makeuserdb will also fail if /etc/userdb has any group or world permissions.

CONVERTING /etc/passwd and vpopmail to /etc/userdb format

The pw2userdb script reads /etc/passwd and /etc/shadow then converts all entries to the format used in /etc/userdb, printing the result on standard output. The output can be redirected to /etc/userdb, or to a file in this subdirectory. Linear searches of /etc/passwd can be very slow when you have tens of thousands of accounts. Programs like maildrop always look in /etc/userdb first, so by having the system password file in the /etc/userdb it is possible to significantly reduce the amount of time it takes to look it up.

After saving the output of pw2userdb, you must still run makeuserdb to create /etc/userdb.dat.

The vchkpw2userdb script is used to convert vpopmail-style directory hierarchy to the /etc/userdb format. vpopmail/vchkpw is often used to implement virtual mailboxes that share the same userid.

Generally, an account named 'vpopmail' is reserved for this purpose. In that account the file users/vpasswd has the same structure as /etc/passwd, and performs a similar function, except that all userid in users/vpasswd have the same userid. Additionally, the domains subdirectory is used to store virtual accounts for multiple domains. For example, domains/example.com/vpasswd contains the passwd file for domain example.com. Additionally, some systems implement a soft link, domains/default, that points to a domain that's considered a "default" domain.

The vchkpw2userdb script takes all of this, and attempts to convert it into the /etc/userdb format. The --vpopmailhost option specifies the top level directory, if it is not the home directory of the vpopmail account.

The vchkpw2userdb script prints the results on standard output. If specified, the --todir option, attempts to convert all vpasswd files one at a time, saving each one individually in dir. For example:

mkdir /etc/userdb
vchkpw2userdb --todir=/etc/userdb/vpopmail
makeuserdb

It is still necessary to run makeuserdb, of course, to create the binary database.

NOTE: You are still required to create the /etc/userdb entry which maps system userids back to accounts, "=uid<TAB>name", if that's applicable. vchkpw2userdb will not do it for you.

NOTE: makeuserdb may complain about duplicate entries, if your "default" entries in users/vpasswd or domains/default/vpasswd are the same as anything in any other /etc/userdb file. It is also likely that you'll end up with duplicate, but distinct, entries for every account in the default domain. For example, if your default domain is example.com, you'll end up with duplicate entries - you'll have entries for both user and user@example.com.

If you intend to maintain the master set of accounts using vchkpw/vpopmail, in order to avoid cleaning this up every time, you might want to consider doing the following: run vchkpw2userdb once, using the --todir option. Then, go into the resulting directory, and replace one of the redundant files with a soft link to /dev/null. This allows you to run vchkpw2userdb without having to go in and cleaning up again, afterwards.

FILES

/etc/userdb

/etc/userdb.dat

/etc/userdbshadow.dat

/etc/userdb.tmp
    temporary file

/etc/userdbshadow.tmp
    temporary file

BUGS

*pw must be encrypted via crypt.

makeuserdb is a Perl script, and uses Perl's portable locking. Perl's documentation notes that certain combinations of locking options may not work with some networks.

SEE ALSO

userdb(8), maildrop(1), courier(1), maildirquota(8)