Not using a temporary file when locking files for writing.

The temporary file was not actually useful, because we
could never really get atomic renames, for annoying,
complicated reasons.

This hopefully finally fixes #1812.

Signed-off-by: Luke Kanies <luke@madstop.com>

3 files changed, 15 insertions, 49 deletions

diff --git a/lib/puppet/util/file_locking.rb b/lib/puppet/util/file_locking.rb
index 80a0b2b0c..101ece308 100644
--- a/lib/puppet/util/file_locking.rb
+++ b/lib/puppet/util/file_locking.rb
@@ -21,6 +21,11 @@ module Puppet::Util::FileLocking
         tmpfile = file + ".tmp"
 
         unless mode
+            # It's far more likely that the file will be there than not, so it's
+            # better to stat once to check for existence and mode.
+            # If we can't stat, it's most likely because the file's not there,
+            # but could also be because the directory isn't readable, in which case
+            # we won't be able to write anyway.
             begin
                 mode = File.stat(file).mode
             rescue
@@ -31,15 +36,7 @@ module Puppet::Util::FileLocking
         Puppet::Util.sync(file).synchronize(Sync::EX) do
             File.open(file, "w", mode) do |rf|
                 rf.lock_exclusive do |lrf|
-                    File.open(tmpfile, "w", mode) do |tf|
-                        yield tf
-                    end
-                    begin
-                        File.rename(tmpfile, file)
-                    rescue => detail
-                        File.unlink(tmpfile) if File.exist?(tmpfile)
-                        raise Puppet::Error, "Could not rename %s to %s: %s; file %s was unchanged" % [file, tmpfile, Thread.current.object_id, detail, file]
-                    end
+                    yield lrf
                 end
             end
         end
diff --git a/spec/integration/util/file_locking.rb b/spec/integration/util/file_locking.rb
index f8e21ed6e..680b3d1ed 100755
--- a/spec/integration/util/file_locking.rb
+++ b/spec/integration/util/file_locking.rb
@@ -9,9 +9,9 @@ describe Puppet::Util::FileLocking do
         file = Tempfile.new("puppetspec")
         file.close!()
         file = file.path
-        File.open(file, "w") { |f| f.puts "starting" }
-
         data = {:a => :b, :c => "A string", :d => "another string", :e => %w{an array of strings}}
+        File.open(file, "w") { |f| f.puts YAML.dump(data) }
+
         threads = []
         sync = Sync.new
         9.times { |a|
@@ -19,7 +19,7 @@ describe Puppet::Util::FileLocking do
                 9.times { |b|
                     sync.synchronize(Sync::SH) {
                         Puppet::Util::FileLocking.readlock(file) { |f|
-                            YAML.load(f.read)
+                            YAML.load(f.read).should == data
                         }
                     }
                     sleep 0.01
diff --git a/spec/unit/util/file_locking.rb b/spec/unit/util/file_locking.rb
index a8b0c1840..70003faa1 100755
--- a/spec/unit/util/file_locking.rb
+++ b/spec/unit/util/file_locking.rb
@@ -98,49 +98,18 @@ describe Puppet::Util::FileLocking do
             Puppet::Util::FileLocking.writelock('/file')
         end
 
-        it "should write to a temporary file" do
+        it "should allow the caller to write to the locked file" do
             fh = mock 'fh'
             File.expects(:open).yields fh
 
             lfh = mock 'locked_filehandle'
-            fh.expects(:lock_exclusive).yields lfh
+            fh.expects(:lock_exclusive).yields(lfh)
 
-            tf = mock 'tmp_filehandle'
-            File.expects(:open).with { |path, *args| path == "/file.tmp" }.yields tf
+            lfh.expects(:print).with "foo"
 
-            result = nil
-            File.stubs(:rename)
-            Puppet::Util::FileLocking.writelock('/file') { |f| result = f }
-            result.should equal(tf)
-        end
-
-        it "should rename the temporary file to the normal file" do
-            fh = stub 'fh'
-            fh.stubs(:lock_exclusive).yields fh
-            File.stubs(:open).yields fh
-
-            File.expects(:rename).with("/file.tmp", "/file")
-            Puppet::Util::FileLocking.writelock('/file') { |f| }
-        end
-
-        it "should fail if it cannot rename the file" do
-            fh = stub 'fh'
-            fh.stubs(:lock_exclusive).yields fh
-            File.stubs(:open).yields fh
-
-            File.expects(:rename).with("/file.tmp", "/file").raises(RuntimeError)
-            lambda { Puppet::Util::FileLocking.writelock('/file') { |f| } }.should raise_error(Puppet::Error)
-        end
-
-        it "should remove the temporary file if the rename fails" do
-            fh = stub 'fh'
-            fh.stubs(:lock_exclusive).yields fh
-            File.stubs(:open).yields fh
-
-            File.expects(:rename).with("/file.tmp", "/file").raises(RuntimeError)
-            File.expects(:exist?).with("/file.tmp").returns true
-            File.expects(:unlink).with("/file.tmp")
-            lambda { Puppet::Util::FileLocking.writelock('/file') { |f| } }.should raise_error(Puppet::Error)
+            Puppet::Util::FileLocking.writelock('/file') do |f|
+                f.print "foo"
+            end
         end
     end
 end