generate the password databases
pwd_mkdb utility creates
secure and insecure databases for the specified file. These databases are then
installed into /etc/spwd.db and
/etc/pwd.db respectively. The file is installed into
/etc/master.passwd. The file must be in the correct
It is important to note that the format used in this system is different from
the historic Version 7 style format.
The options are as follows:
- Check if the password file is in the correct format. Do not change, add,
or remove any files.
pwd_mkdb 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.
- Create a Version 7 style password file and install it into
- Ignore locking failure of the 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
-d option for
locking to be ignored. Other use of this option is strongly
- Store databases into specified destination directory instead of
- 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
- 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
pwd_mkdb in megabytes will be a
little bit more than twice the figure specified here. The default is 2
The two databases differ in that the secure version contains the
user's encrypted password and the insecure version has an asterisk
The databases are used by the C library password routines (see
pwd_mkdb utility exits zero on
success, non-zero on failure.
PW_SCAN_BIG_IDS environment variable is set,
pwd_mkdb 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.
Regenerate the password database after manually editing or replacing the
- The insecure password database file.
- A temporary file.
- The secure password database file.
- A temporary file.
- The current password file.
- A Version 7 format password file.
Previous versions of the system had a program similar to
/usr/sbin/pwd_mkdb -p /etc/master.passwd
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.
Because of the necessity for atomic update of the password files,
to install them. This, however, requires that the file specified on the
command line live on the same file system as the /etc
There are the obvious races with multiple people running
pwd_mkdb on different password files at the same
time. The front-ends to
handle the locking necessary to avoid this problem.