Merge pull request #8945 from briancain/4666/master/dupe-nfs-export-linux

Remove duplicate export folders before writing /etc/exports

lib/vagrant/errors.rb

@@ -468,6 +468,10 @@ module Vagrant
       error_key(:nfs_bad_exports)
     end
 
+    class NFSDupePerms < VagrantError
+      error_key(:nfs_dupe_permissions)
+    end
+
     class NFSExportsFailed < VagrantError
       error_key(:nfs_exports_failed)
     end

plugins/hosts/linux/cap/nfs.rb

@@ -29,6 +29,7 @@ module VagrantPlugins
           nfs_start_command = env.host.capability(:nfs_start_command)
 
           nfs_opts_setup(folders)
+          folders = folder_dupe_check(folders)
           output = Vagrant::Util::TemplateRenderer.render('nfs/exports_linux',
                                            uuid: id,
                                            ips: ips,
@@ -84,6 +85,37 @@ module VagrantPlugins
 
         protected
 
+        # Takes a hash of folders and removes any duplicate exports that
+        # share the same hostpath to avoid duplicate entries in /etc/exports
+        # ref: GH-4666
+        def self.folder_dupe_check(folders)
+          return_folders = {}
+          # Group by hostpath to see if there are multiple exports coming
+          # from the same folder
+          export_groups = folders.values.group_by { |h| h[:hostpath] }
+
+          # We need to check that each group key only has 1 value,
+          # and if not, check each nfs option. If all nfs options are the same
+          # we're good, otherwise throw an exception
+          export_groups.each do |path,group|
+            if group.size > 1
+              # if the linux nfs options aren't all the same throw an exception
+              group1_opts = group.first[:linux__nfs_options]
+
+              if !group.all? {|g| g[:linux__nfs_options] == group1_opts}
+                raise Vagrant::Errors::NFSDupePerms, hostpath: group.first[:hostpath]
+              else
+                # if they're the same just pick the first one
+                return_folders[path] = group.first
+              end
+            else
+              # just return folder, there are no duplicates
+              return_folders[path] = group.first
+            end
+          end
+          return_folders
+        end
+
         def self.nfs_cleanup(remove_ids)
           return if !File.exist?(NFS_EXPORTS_PATH)
 

templates/locales/en.yml

@@ -912,6 +912,9 @@ en:
         command: %{command}
         stdout: %{stdout}
         stderr: %{stderr}
+      nfs_dupe_permissions: |-
+        You have attempted to export the same nfs host path at %{hostpath} with
+        different nfs permissions. Please pick one permission and reload your guest.
       nfs_cant_read_exports: |-
         Vagrant can't read your current NFS exports! The exports file should be
         readable by any user. This is usually caused by invalid permissions

test/unit/plugins/hosts/linux/cap/nfs_test.rb

@@ -79,6 +79,42 @@ EOH
       expect(exports_content).to include("/tmp")
       expect(exports_content).not_to include("/var")
     end
+
+    it "throws an exception with at least 2 different nfs options" do
+      folders = {"/vagrant"=>
+                 {:hostpath=>"/home/vagrant",
+                  :linux__nfs_options=>["rw","all_squash"]},
+                 "/var/www/project"=>
+                 {:hostpath=>"/home/vagrant",
+                  :linux__nfs_options=>["rw","sync"]}}
+
+      expect { cap.nfs_export(env, ui, SecureRandom.uuid, ["127.0.0.1"], folders) }.
+        to raise_error Vagrant::Errors::NFSDupePerms
+    end
+
+    it "writes only 1 hostpath for multiple exports" do
+      folders = {"/vagrant"=>
+                 {:hostpath=>"/home/vagrant",
+                  :linux__nfs_options=>["rw","all_squash"]},
+                 "/var/www/otherproject"=>
+                 {:hostpath=>"/newhome/otherproject",
+                  :linux__nfs_options=>["rw","all_squash"]},
+                 "/var/www/project"=>
+                 {:hostpath=>"/home/vagrant",
+                  :linux__nfs_options=>["rw","all_squash"]}}
+      valid_id = SecureRandom.uuid
+      content =<<-EOH
+\n# VAGRANT-BEGIN: #{Process.uid} #{valid_id}
+"/home/vagrant" 127.0.0.1(rw,all_squash,anonuid=,anongid=,fsid=)
+"/newhome/otherproject" 127.0.0.1(rw,all_squash,anonuid=,anongid=,fsid=)
+# VAGRANT-END: #{Process.uid} #{valid_id}
+EOH
+
+      cap.nfs_export(env, ui, valid_id, ["127.0.0.1"], folders)
+      exports_content = File.read(exports_path)
+      expect(exports_content).to eq(content)
+    end
+
   end
 
   describe ".nfs_prune" do