NAME
pwd_mkdb —
generate the password
databases
SYNOPSIS
pwd_mkdb |
[-BLlpsvw]
[-c
cachesize]
[-d
directory]
[-u
username]
[-V
version] file |
DESCRIPTION
pwd_mkdb creates
db(3) style 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 format (see
passwd(5)). 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:
-
-
- -B
- Store data in big-endian format (see also
-L).
-
-
- -c
cachesize
- Specify the size of the memory cache in megabytes 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. If unspecified,
this value will be calculated based on the size of the input file up to a
maximum of 8 megabytes.
-
-
- -d
directory
- Change the root directory of the generated files from
“/” to directory.
-
-
- -L
- Store data in little-endian format (see also
-B).
-
-
- -l
- Use syslog(3)
to report errors.
-
-
- -p
- Create a Version 7 style password file and install it into
“/etc/passwd”.
-
-
- -s
- Update the secure database only. This is useful when only
encrypted passwords have changed. This option negates the effect of any
-p option.
-
-
- -u
name
- Don't re-build the database files, but instead modify or
add entries for the specified user only. This option may only be used when
the line number and user name in the password file have not changed, or
when adding a new user from the last line in the password file.
-
-
- -V
version
- Upgrade or downgrade databases to the numbered version.
Version
0
is the old format (up to and including
NetBSD 5.0) with the 4 byte time fields and
version 1
is the new format with the 8 byte time
fields (greater than NetBSD 5.0).
NetBSD 5.0 cannot read version
1
databases. All versions above
NetBSD 5.0 can read and write both version
0
and version 1
databases.
By default the databases stay in the version they were before the command
was run.
-
-
- -v
- Mention when a version change occurs.
-
-
- -w
- Print a warning if the system is using old style
databases.
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
getpwent(3)).
FILES
- /etc/master.passwd
- The current password file.
- /etc/passwd
- A Version 7 format password file.
- /etc/pwd.db
- The insecure password database file.
- /etc/pwd.db.tmp
- A temporary file.
- /etc/spwd.db
- The secure password database file.
- /etc/spwd.db.tmp
- A temporary file.
EXIT STATUS
pwd_mkdb exits zero on success, non-zero on failure.
COMPATIBILITY
Previous versions of the system had a program similar to
pwd_mkdb which built
dbm 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.
SEE ALSO
chpass(1),
passwd(1),
pwhash(1),
db(3),
getpwent(3),
pw_mkdb(3),
syslog(3),
passwd(5),
useradd(8),
userdel(8),
usermod(8),
vipw(8)
BUGS
Because of the necessity for atomic update of the password files,
pwd_mkdb uses
rename(2) to install them. This,
however, requires that the file specified on the command line live on the same
file system as the “
/etc” directory.
There are the obvious races with multiple people running
pwd_mkdb on different password files at the same time. The
front-ends to
chpass(1),
passwd(1),
useradd(8),
userdel(8),
usermod(8), and
vipw(8) handle the locking
necessary to avoid this problem.
The database files are copied when the
-u option is used. Real
locking would make this unnecessary.
Although the DB format is endian-transparent, the data stored in the DB is not.
Also, the format doesn't lend itself to insertion or removal of records from
arbitrary locations in the password file. This is difficult to fix without
breaking compatibility.
Using the
-u option on a system where multiple users share the
same UID can have unexpected results.