1 files changed, 68 insertions, 0 deletions
diff --git a/lib/byteback/util.rb b/lib/byteback/util.rb
new file mode 100755
index 0000000..f9f6c62
--- /dev/null
+++ b/lib/byteback/util.rb
@@ -0,0 +1,68 @@
+require 'tempfile'
+
+module Byteback
+	module Util
+		@@lockfile = "/var/run/byteback/byteback.lock"
+
+		def remove_lockfile!
+		  begin
+		    File.unlink(@@lockfile)
+		  rescue Errno::ENOENT
+		  end
+		end
+
+		def claim_lockfile!
+			# Check the lockfile first
+			if File.directory?(File.dirname(@@lockfile))
+			  if File.exists? @@lockfile
+			    # check the lockfile is sane
+			    exist_pid = File.read(@@lockfile).to_i
+			    if exist_pid > 1 and exist_pid < (File.read("/proc/sys/kernel/pid_max").to_i)
+			      begin
+			        Process.getpgid(exist_pid)
+			        # if no exception, process is running, abort
+			        fatal("Process is running (#{exist_pid} from #{@@lockfile})")
+			      rescue Errno::ESRCH
+			        # no process running with that pid, pidfile is stale
+			        remove_lockfile!
+			      end
+			    else
+			      # lockfile isn't sane, remove it and continue
+			      remove_lockfile!
+			    end
+			  end
+			else
+			  Dir.mkdir(File.dirname(@@lockfile))
+			  # lockfile didn't exist so just carry on
+			end
+
+			# Own the pidfile ourselves
+			File.open(@@lockfile, "w") do |lockfile|
+			  lockfile.puts Process::pid
+			end
+		end
+
+		def lock_out_other_processes(name)
+			@@lockfile = "/var/run/byteback/#{name}.lock"
+			claim_lockfile!
+			at_exit { remove_lockfile! }
+		end
+
+		def log_system(*args)
+			debug("system: " + args.map { |a| / /.match(a) ? "\"#{a}\"" : a }.join(" "))
+			rd, wr = IO.pipe
+			pid = fork
+			if pid.nil? # child
+				rd.close
+				STDOUT.reopen(wr)
+				STDERR.reopen(wr)
+				# any cleanup actually necessary here?
+				exec(*args)
+			end
+			wr.close
+			rd.each_line { |line| debug(line.chomp) }
+			pid2, status = Process.waitpid2(pid, 0)
+			status.exitstatus
+		end
+	end
+end