Linux System Administration Recipes A Problem-Solution Approach

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CHAPTER 2 ■ CENTRALIZING YOUR NETWORK: KERBEROS, LDAP, AND NFS0708 die "Usage is adduser.pl [username] ["realname"]\n" if length(@ARGV) != 1;0910 my $username = $ARGV[0];11 my $realname = $ARGV[1];1213 # Plain LDAP version if you prefer this to the LDAPS version14 # my $ldap = Net::LDAP->new( 'ldapserver.example.com');15 my $ldap = Net::LDAPS->new( 'ldapserver.example.com',16 verify => 'optional',17 cafile => '/etc/ldap/cacert.pem' ) or die $@;18 my $mesg = $ldap->bind;1920 $mesg = $ldap->search( base => "ou=people,dc=example,dc=com",21 filter => "(uid=$username)",22 );23 $mesg->code && die $mesg->error;2425 my $searchResults = $mesg->count;26 die "Error! Username already exists!" unless $searchResults == 0;2728 $mesg = $ldap->search ( base => "ou=people,dc=example,dc=com",29 attrs => [ 'uidNumber' ],30 );31 my @entries = $mesg->sorted('uidNumber');32 my $entry = pop @entries;33 my $newuid = $entry->get_value( 'uidNumber' );34 $newuid++;3536 my $result = $ldap->add("uid=$username,ou=people,dc=example,dc=com",37 attr => [ 'cn' => $realname,38 'uid' => $userid,39 'uidNumber' => $newuid,40 'mail' => '$username@example.com',41 'homeDirectory' => '/home/$username',42 'objectclass' => [ 'person', 'inetOrgPerson',43 'posixAccount' ]44 ]45 );4647 $mesg = $ldap->unbind;If using ldaps:///, you will need the CA certificate for the CA that signed your server’s certificate.For a proper CA (as opposed to self-signed), you should be able to use the capath (rather than cafile)attribute to set the directory where CA certificates live rather than needing to give a specific file.Line 17 performs an anonymous bind. If you want to bind with a specific DN (for example, toauthenticate as your admin user, if you’re not using Kerberos), you can provide extra options:my $adminuser = "cn=root,dc=example,dc=com"my $password = "mypasswd";$mesg = $ldap->bind( $adminuser, password => $password );50Download at WoweBook.Com
CHAPTER 2 ■ CENTRALIZING YOUR NETWORK: KERBEROS, LDAP, AND NFSOr you can use an SASL mechanism by giving an Authen::SASL object as an argument:$mesg = $ldap->bind( "cn=root,dc=example,dc=com", sasl => $sasl );Lines 19–25 search the directory for an existing user with the given UID. Net::LDAP::Search acts as acontainer for the results of an LDAP search, and there is a Net::LDAP::Entry for each individual result.In this example, you’re checking to make sure that the username doesn’t already exist, so all youneed do is to find the number of entries returned. If it’s 0, the username is free. Line 24 handles this: thecount method gives the number of entries returned. $mesg here is a Net::LDAP::Search object.■ Note Numerous other methods are available for interacting with a Net::LDAP::Search object. You can retrievean entry by number from the Net::LDAP::Search container, sort the entries, pop off an entry at a time, or returnan array of all the Net::LDAP::Entry objects found by the search.The search method will accept attribute specifications, just as ldapsearch will (see recipe 2-7):$mesg = $ldap->search( filter => "(uid=jkemp)",base =>"ou=people,dc=example,dc=com",attrs => ['uid', 'cn', 'homeDirectory'] );This will return the uid, cn, and homeDirectory of the user jkemp.To look at the entries returned, you use the Net::LDAP::Entries methods. Lines 27–33 look for thenext free user ID to allocate to our user. All the users are returned, as a Net::LDAP::Search object (acontainer of Net::LDAP::Entries objects), and then are sorted by uidNumber and dumped into an array ofNet::LDAP::Entry objects (line 30). Line 31 pops the highest one off the stack. Our next free uidNumber isthe value for that entry, plus one.■ Note There are also methods to return the nth entry from a search; but in this case we don’t use them becausethe order of our results matters (we want to get the highest existing userID and then add one), so we have to sortthe results first.Line 35–44 use the $ldap->add method (the most straightforward option) to add an entry of a userwith attributes set in that hash. Attributes with multiple values (as with objectclass) use a list.Alternatively, you could use the Net::LDAP::Entry object to write directly to the LDAP directory:my $entry = Net::LDAP::Entry->new();# set DN$entry->dn("uid=$userid,ou=people,dc=example,dc=com");# You can add attributes all at once, or in as many operations as you like51Download at WoweBook.Com
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Contents■About the Author .......
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■ CONTENTS3-7. Writing a Nagios P
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■ CONTENTS■Chapter 8: Using the
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■ CONTENTSAbout the Author■Juli
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■ CONTENTSAcknowledgmentsMany tha
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■ CONTENTSIntroductionThis book i
Page 19 and 20: ■ INTRODUCTIONDownloading the Cod
Page 21 and 22: C H A P T E R 1■ ■ ■Saving Yo
Page 23 and 24: CHAPTER 1 ■ SAVING YOURSELF EFFOR
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C H A P T E R 5■ ■ ■Working w
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CHAPTER 5 ■ WORKING WITH FILESYST
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C H A P T E R 6■ ■ ■Securing
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CHAPTER 6 ■ SECURING YOUR SYSTEMS
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CHAPTER 7 ■ WORKING WITH APACHEOn
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CHAPTER 7 ■ WORKING WITH APACHE
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CHAPTER 7 ■ WORKING WITH APACHEAl
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CHAPTER 7 ■ WORKING WITH APACHE
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C H A P T E R 8■ ■ ■Making Be
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CHAPTER 8 ■ USING THE COMMAND LIN
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CHAPTER 9 ■ WORKING WITH TEXT IN
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C H A P T E R 10■ ■ ■Things G
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CHAPTER 10 ■ THINGS GO IN, THINGS
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C H A P T E R 11■ ■ ■Tracking
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CHAPTER 11 ■ TRACKING DOWN BUGSTh
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CHAPTER 11 ■ TRACKING DOWN BUGS01
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CHAPTER 11 ■ TRACKING DOWN BUGS
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CHAPTER 11 ■ TRACKING DOWN BUGS#
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C H A P T E R 12■ ■ ■Managing
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CHAPTER 12 ■ MANAGING TIME AND PE
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APPENDIX■ ■ ■Perl TipsSee rec
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APPENDIX ■ PERL TIPS• Date::Par
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APPENDIX ■ PERL TIPSPerl Syntax N
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■ ■ ■Index■Symbols$CDPATH,
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■ INDEXenscript option (printing)
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■ INDEX■NNagiosadding hosts to,
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■ INDEXsyslogcentralized logging
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Linux System Administration Recipes A Problem-Solution Approach

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