New Formula: DenyHosts

DenyHosts is a tool that monitors system logs for unauthorized SSH access
attempts and bans offending IP addresses by adding them to /etc/hosts.deny. A
launchctl plist is provided that runs the tool as a cron job. DenyHosts does
have a "daemon mode" but it is designed for rc.d style scripts and doesn't fit
the idiom that launchctl expects (direct control of the daemon process).

Also see issue Homebrew/homebrew#2955.

Formula/denyhosts.rb

@@ -0,0 +1,181 @@
+require 'formula'
+
+class Denyhosts < Formula
+  url 'http://downloads.sourceforge.net/project/denyhosts/denyhosts/2.6/DenyHosts-2.6.tar.gz'
+  homepage 'http://denyhosts.sourceforge.net/'
+  md5 'fc2365305a9402886a2b0173d1beb7df'
+
+  def patches
+    # The original DenyHosts scripts will be installed to libexec with the
+    # `-dist` suffixes. The patchfile modifies the copies to set some defaults.
+    cp 'daemon-control-dist', 'daemon-control'
+    cp 'denyhosts.cfg-dist', 'denyhosts.cfg'
+    DATA
+  end
+
+  def install
+    # If the `libpath` is relative, instead of absolute, we can influence the
+    # 'data path' via command line arguments to `setup.py`.
+    inreplace 'setup.py' do |s|
+      s.change_make_var! 'libpath', "''"
+    end
+
+    # Make it so that all DenyHosts tools have a default path that points at
+    # our config file.
+    inreplace 'DenyHosts/constants.py' do |s|
+      s.change_make_var! 'CONFIG_FILE', etc + 'denyhosts.cfg'
+    end
+    # Install mostly into libexec (a la Duplicity)
+    system "python", "setup.py", "install",
+                     "--prefix=#{prefix}",
+                     "--install-lib=#{libexec}",
+                     "--install-scripts=#{libexec}",
+                     "--install-data=#{libexec}"
+    libexec.install 'daemon-control'
+
+    # Don't overwrite the config file if it exists---the user may have tweaked
+    # it.
+    etc.install 'denyhosts.cfg' unless (etc + 'denyhosts.cfg').exist?
+
+    sbin.mkpath
+    ln_s libexec + 'denyhosts.py', sbin + 'denyhosts'
+    ln_s libexec + 'daemon-control', sbin + 'daemon-control'
+
+    plist = prefix + 'org.denyhosts.cron.plist'
+    plist.write cron_plist
+    plist.chmod 0644
+  end
+
+  def cron_plist
+    <<-EOS.undent
+      <?xml version="1.0" encoding="UTF-8"?>
+      <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+      <plist version="1.0">
+      <dict>
+        <key>Label</key>
+        <string>org.denyhosts.cron</string>
+        <key>ProgramArguments</key>
+        <array>
+          <string>#{HOMEBREW_PREFIX}/sbin/denyhosts</string>
+        </array>
+        <key>RunAtLoad</key>
+        <true/>
+        <key>KeepAlive</key>
+        <false/>
+        <key>StartInterval</key>
+        <integer>600</integer>
+      </dict>
+      </plist>
+    EOS
+  end
+
+  def caveats
+    <<-EOS.undent
+      Unless it exists already, a denyhosts.cfg file has been written to:
+        #{etc}/denyhosts.cfg
+
+      All DenyHosts scripts will load this file by default unless told to use
+      a different one.
+
+      A launchctl plist has been created that will run DenyHosts to update
+      /etc/hosts.deny every 10 minutes. It will need to be run by the user that
+      owns /etc/hosts.deny, usually root, and can be set to load at startup
+      via:
+        sudo cp #{prefix}/org.denyhosts.cron.plist /Library/LaunchDaemons/
+
+    EOS
+  end
+end
+
+__END__
+
+Set DenyHosts defaults for OS X.
+
+See: http://trac.macports.org/browser/trunk/dports/security/denyhosts/files/patch-denyhosts.cfg-dist.diff
+
+
+diff --git a/daemon-control b/daemon-control
+index dd49315..b2bb838 100755
+--- a/daemon-control
++++ b/daemon-control
+@@ -11,9 +11,9 @@
+ #### Edit these to suit your configuration ####
+ ###############################################
+ 
+-DENYHOSTS_BIN   = "/usr/bin/denyhosts.py"
+-DENYHOSTS_LOCK  = "/var/lock/subsys/denyhosts"
+-DENYHOSTS_CFG   = "/usr/share/denyhosts/denyhosts.cfg"
++DENYHOSTS_BIN   = "HOMEBREW_PREFIX/sbin/denyhosts"
++DENYHOSTS_LOCK  = "HOMEBREW_PREFIX/var/run/denyhosts.pid"
++DENYHOSTS_CFG   = "HOMEBREW_PREFIX/etc/denyhosts.cfg"
+ 
+ PYTHON_BIN      = "/usr/bin/env python"
+ 
+diff --git a/denyhosts.cfg b/denyhosts.cfg
+index 6551b3f..c95fcb6 100644
+--- a/denyhosts.cfg
++++ b/denyhosts.cfg
+@@ -9,7 +9,7 @@
+ # argument
+ #
+ # Redhat or Fedora Core:
+-SECURE_LOG = /var/log/secure
++# SECURE_LOG = /var/log/secure
+ #
+ # Mandrake, FreeBSD or OpenBSD: 
+ #SECURE_LOG = /var/log/auth.log
+@@ -19,7 +19,7 @@ SECURE_LOG = /var/log/secure
+ #
+ # Mac OS X (v10.4 or greater - 
+ #   also refer to:   http://www.denyhosts.net/faq.html#macos
+-#SECURE_LOG = /private/var/log/asl.log
++SECURE_LOG = /private/var/log/secure.log
+ #
+ # Mac OS X (v10.3 or earlier):
+ #SECURE_LOG=/private/var/log/system.log
+@@ -88,9 +88,9 @@ PURGE_DENY =
+ # eg.   sshd: 127.0.0.1  # will block sshd logins from 127.0.0.1
+ #
+ # To block all services for the offending host:
+-#BLOCK_SERVICE = ALL
++BLOCK_SERVICE = ALL
+ # To block only sshd:
+-BLOCK_SERVICE  = sshd
++# BLOCK_SERVICE  = sshd
+ # To only record the offending host and nothing else (if using
+ # an auxilary file to list the hosts).  Refer to: 
+ # http://denyhosts.sourceforge.net/faq.html#aux
+@@ -150,7 +150,7 @@ DENY_THRESHOLD_RESTRICTED = 1
+ # Note: it is recommended that you use an absolute pathname
+ # for this value (eg. /home/foo/denyhosts/data)
+ #
+-WORK_DIR = /usr/share/denyhosts/data
++WORK_DIR = HOMEBREW_PREFIX/var/denyhosts
+ #
+ #######################################################################
+ 
+@@ -192,13 +192,13 @@ HOSTNAME_LOOKUP=YES
+ # running at a time.
+ #
+ # Redhat/Fedora:
+-LOCK_FILE = /var/lock/subsys/denyhosts
++#LOCK_FILE = /var/lock/subsys/denyhosts
+ #
+ # Debian
+ #LOCK_FILE = /var/run/denyhosts.pid
+ #
+ # Misc
+-#LOCK_FILE = /tmp/denyhosts.lock
++LOCK_FILE = HOMEBREW_PREFIX/var/run/denyhosts.pid
+ #
+ ######################################################################
+ 
+@@ -432,7 +432,7 @@ AGE_RESET_INVALID=10d
+ # this is the logfile that DenyHosts uses to report it's status.
+ # To disable logging, leave blank.  (default is: /var/log/denyhosts)
+ #
+-DAEMON_LOG = /var/log/denyhosts
++DAEMON_LOG = HOMEBREW_PREFIX/var/log/denyhosts.log
+ #
+ # disable logging:
+ #DAEMON_LOG =