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Shadow Password module

Copyright (C) 1998-1999 Takaaki Tateishi <>
Modified at: <1999/8/19 06:47:14 by ttate>
License: Free for any use with your own risk!

1. What's this

This is the module which used when you access linux shadow password files.  

Recent versions work on both Linux and Solaris.

2. install

ruby extconf.rb
(make install)

* Note:
 Version 2 was developed to compile on Ruby 1.9.  1.8 compatibility should be
 still present, but no promises about earlier versions of Ruby.

3. Shadow::Passwd module's methods


* Note: sgetspent is not available under Solaris and some other operating
  systems.  In current versions, that method will be completely missing.

4. Structure

Shadow::Passwd::Entry (Struct::PasswdEntry)
       sp_namp - pointer to null-terminated user name.
       sp_pwdp - pointer to null-terminated password.
       sp_lstchg  -  days  since  Jan  1,  1970 password was last
       sp_min - days before which password may not be changed.
       sp_max - days after which password must be changed.
       sp_warn - days before password is to expire that  user  is
       warned of pending password expiration.
       sp_inact  -  days  after  password expires that account is
                    considered inactive and disabled.
       sp_expire - days since Jan 1, 1970 when  account  will  be

5. Description

getspent,  getspname,  fgetspent and sgetspent each return
a structure Shadow::Passwd::Entry.    getspent returns the
next entry from the file,   and fgetspent returns the next
entry from the given stream. sgetspent returns a structure
Shadow::Passwd::Entry using the provided string as input.
getspnam searches from the current position in the file for
an entry matching name.
if you get EOF from each operation, you will get nil.

setspent and endspent may be used to begin and end, respe-
ctively, access to the shadow password file.

lckpwdf(lock) and ulckpwdf(unlock) methods should be used
to insure exclusive access to the /etc/shadow file.
when either method fail, Exception Shadow::FileLock is raised.
if you use lock as the iterator, unlock is automatically called
when you exit the iterator block.

6. Reference

* man shadow
* /usr/include/shadow.h

Original Author:
  Takaaki Tateishi <>

This GitHub repository is maintained by Adam Palmblad <>.  I'll
do my best to keep the repository reasonably up-to-date if you care to send pull requests.
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