Fixed mount Resource for bind mounts is not idempotent.

Added a separate linux mount provider.
Define 'mounted?' method and used 'findmnt -rn' command to list mount points along with device.
Added linux_mount recipe to kitchen-tests.

Signed-off-by: antima-gupta <agupta@msystechnologies.com>

5 files changed, 167 insertions, 0 deletions

diff --git a/kitchen-tests/cookbooks/end_to_end/recipes/_linux_mount.rb b/kitchen-tests/cookbooks/end_to_end/recipes/_linux_mount.rb
new file mode 100644
index 0000000000..207ef9d1fb
--- /dev/null
+++ b/kitchen-tests/cookbooks/end_to_end/recipes/_linux_mount.rb
@@ -0,0 +1,20 @@
+mount "/proc" do
+  device "proc"
+  fstype "proc"
+  options %w{bind rw}
+  action %i{ mount enable }
+end
+
+mount "/mnt" do
+  device "/tmp"
+  fstype "ext4"
+  options %w{bind rw}
+  action %i{ mount enable }
+end
+
+mount "/mnt" do
+  device "/etc"
+  fstype "ext4"
+  options %w{bind rw}
+  action %i{ mount enable }
+end
\ No newline at end of file
diff --git a/kitchen-tests/cookbooks/end_to_end/recipes/linux.rb b/kitchen-tests/cookbooks/end_to_end/recipes/linux.rb
index 8fae36662c..bb94fb88d1 100644
--- a/kitchen-tests/cookbooks/end_to_end/recipes/linux.rb
+++ b/kitchen-tests/cookbooks/end_to_end/recipes/linux.rb
@@ -122,6 +122,7 @@ include_recipe "::_cron"
 include_recipe "::_ohai_hint"
 include_recipe "::_openssl"
 include_recipe "::_tests"
+include_recipe "::_linux_mount"
 
 # at the moment these do not run properly in docker
 # we need to investigate if this is a snap on docker issue or a chef issue
diff --git a/lib/chef/provider/mount/linux.rb b/lib/chef/provider/mount/linux.rb
new file mode 100644
index 0000000000..25a03c08be
--- /dev/null
+++ b/lib/chef/provider/mount/linux.rb
@@ -0,0 +1,58 @@
+#
+# Author:: Joshua Timberman (<joshua@chef.io>)
+# Copyright:: Copyright (c) Chef Software Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+require_relative "../mount"
+
+class Chef
+  class Provider
+    class Mount
+      class Linux < Chef::Provider::Mount::Mount
+
+        provides :mount, os: "linux"
+
+        def mounted?
+          mounted = false
+
+          # "mount" outputs the mount points as real paths. Convert
+          # the mount_point of the resource to a real path in case it
+          # contains symlinks in its parents dirs.
+          real_mount_point = if ::File.exists? @new_resource.mount_point
+                               ::File.realpath(@new_resource.mount_point)
+                             else
+                               @new_resource.mount_point
+                             end
+
+          shell_out!("findmnt -rn").stdout.each_line do |line|
+            case line
+            when /\A#{Regexp.escape(real_mount_point)}\s+#{device_mount_regex}\s/
+              mounted = true
+              logger.trace("Special device #{device_logstring} mounted as #{real_mount_point}")
+            when %r{\A#{Regexp.escape(real_mount_point)}\s+([/\w])+\s}
+              mounted = false
+              logger.trace("Special device #{$~[1]} mounted as #{real_mount_point}")
+            when %r{\A#{Regexp.escape(real_mount_point)}\s+([/\w])+\[#{device_mount_regex}\]\s}
+              mounted = true
+              logger.trace("Bind device #{device_logstring} mounted as #{real_mount_point}")
+            end
+          end
+          @current_resource.mounted(mounted)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/chef/providers.rb b/lib/chef/providers.rb
index d2e9f1991b..6b099fc2b7 100644
--- a/lib/chef/providers.rb
+++ b/lib/chef/providers.rb
@@ -119,6 +119,7 @@ require_relative "provider/mount/mount"
 require_relative "provider/mount/aix"
 require_relative "provider/mount/solaris"
 require_relative "provider/mount/windows"
+require_relative "provider/mount/linux"
 
 require_relative "provider/remote_file/ftp"
 require_relative "provider/remote_file/sftp"
diff --git a/spec/unit/provider/mount/linux_spec.rb b/spec/unit/provider/mount/linux_spec.rb
new file mode 100644
index 0000000000..feb8d97167
--- /dev/null
+++ b/spec/unit/provider/mount/linux_spec.rb
@@ -0,0 +1,87 @@
+require "spec_helper"
+require "ostruct"
+
+describe Chef::Provider::Mount::Linux do
+  before(:each) do
+    @node = Chef::Node.new
+    @events = Chef::EventDispatch::Dispatcher.new
+    @run_context = Chef::RunContext.new(@node, {}, @events)
+
+    @new_resource = Chef::Resource::Mount.new("/tmp/foo")
+    @new_resource.device      "/dev/sdz1"
+    @new_resource.device_type :device
+    @new_resource.fstype      "ext3"
+
+    @new_resource.supports remount: false
+
+    @provider = Chef::Provider::Mount::Linux.new(@new_resource, @run_context)
+
+    allow(::File).to receive(:exists?).with("/dev/sdz1").and_return true
+    allow(::File).to receive(:exists?).with("/tmp/foo").and_return true
+    allow(::File).to receive(:realpath).with("/dev/sdz1").and_return "/dev/sdz1"
+    allow(::File).to receive(:realpath).with("/tmp/foo").and_return "/tmp/foo"
+  end
+
+  it "should set mounted true if the mount point is found in the mounts list" do
+    allow(@provider).to receive(:shell_out!).and_return(OpenStruct.new(stdout: "/tmp/foo /dev/sdz1 type ext3 (rw)\n"))
+    @provider.load_current_resource
+    expect(@provider.current_resource.mounted).to be_truthy
+  end
+
+  it "should set mounted false if another mount point beginning with the same path is found in the mounts list" do
+    allow(@provider).to receive(:shell_out!).and_return(OpenStruct.new(stdout: "/tmp/foobar /dev/sdz1 type ext3 (rw)\n"))
+    @provider.load_current_resource
+    expect(@provider.current_resource.mounted).to be_falsey
+  end
+
+  it "should set mounted true if the symlink target of the device is found in the mounts list" do
+    # expand the target path to correct specs on Windows
+    target = ::File.expand_path("/dev/mapper/target")
+
+    allow(::File).to receive(:symlink?).with((@new_resource.device).to_s).and_return(true)
+    allow(::File).to receive(:readlink).with((@new_resource.device).to_s).and_return(target)
+
+    allow(@provider).to receive(:shell_out!).and_return(OpenStruct.new(stdout: "/tmp/foo #{target} type ext3 (rw)\n"))
+    @provider.load_current_resource
+    expect(@provider.current_resource.mounted).to be_truthy
+  end
+
+  it "should set mounted true if the symlink target of the device is relative and is found in the mounts list - CHEF-4957" do
+    target = "xsdz1"
+
+    # expand the target path to correct specs on Windows
+    absolute_target = ::File.expand_path("/dev/xsdz1")
+
+    allow(::File).to receive(:symlink?).with((@new_resource.device).to_s).and_return(true)
+    allow(::File).to receive(:readlink).with((@new_resource.device).to_s).and_return(target)
+
+    allow(@provider).to receive(:shell_out!).and_return(OpenStruct.new(stdout: "/tmp/foo #{absolute_target} type ext3 (rw)\n"))
+    @provider.load_current_resource
+    expect(@provider.current_resource.mounted).to be_truthy
+  end
+
+  it "should set mounted true if the mount point is found last in the mounts list" do
+    mount = "#{@new_resource.mount_point} /dev/sdy1 type ext3 (rw)\n"
+    mount << "#{@new_resource.mount_point} #{@new_resource.device} type ext3 (rw)\n"
+
+    allow(@provider).to receive(:shell_out!).and_return(OpenStruct.new(stdout: mount))
+    @provider.load_current_resource
+    expect(@provider.current_resource.mounted).to be_truthy
+  end
+
+  it "should set mounted false if the mount point is not last in the mounts list" do
+    mount = "#{@new_resource.device} on #{@new_resource.mount_point} type ext3 (rw)\n"
+    mount << "/dev/sdy1 on #{@new_resource.mount_point} type ext3 (rw)\n"
+
+    allow(@provider).to receive(:shell_out!).and_return(OpenStruct.new(stdout: mount))
+    @provider.load_current_resource
+    expect(@provider.current_resource.mounted).to be_falsey
+  end
+
+  it "mounted should be false if the mount point is not found in the mounts list" do
+    allow(@provider).to receive(:shell_out!).and_return(OpenStruct.new(stdout: "/dev/sdy1 on /tmp/foo type ext3 (rw)\n"))
+    @provider.load_current_resource
+    expect(@provider.current_resource.mounted).to be_falsey
+  end
+
+end
\ No newline at end of file