Merge pull request #1745 from ElektraInitiative/kdb-mount

Kdb mount

doc/help/elektra-merge-strategy.md

@@ -40,7 +40,9 @@ Currently the following strategies exist:
  * cut:
    Removes existing keys below the resultpath and replaces them with the merged keyset.
 
- * import:
+ * unchanged: (EXPERIMENTAL, only for kdb-mount)
+   Do not fail if the operation does not change anything.
+
+ * import: (DEPRECATED, avoid using it)
    Preserves existing keys in the resultpath if they do not exist in the merged keyset.
    If the key does exist in the merged keyset, it will be overwritten.
-   (avoid using it)

doc/help/kdb-mount.md

@@ -74,6 +74,8 @@ Use `kdb file <path>` to determine where the file(s) are.
   Add a plugin configuration for all plugins.
 - `-W`, `--with-recommends`:
   Also add recommended plugins and warn if they are not available.
+- `-f`, `--force`:
+  Unmount before mounting: Does not fail on already existing mountpoints.
 
 
 

doc/news/_preparation_next_release.md

@@ -30,7 +30,7 @@ For more information, visit [https://libelektra.org](https://libelektra.org).
 - Fosdem Talk about Elektra
 - CC-licensed book about Elektra published
 - Maturing of plugins
-- Elektra with encryption:
+- Elektra with encryption
 - Preparation for switch to INI as default storage
 
 ### Fosdem Talk about Elektra in Main Track
@@ -85,7 +85,7 @@ While `crypto` encrypts individual values within configuration files, `fcrypt` e
 
 For this release Peter Nirschl prepared a demo showing Elektra's cryptographic abilities:
 
-![asciicast](https://asciinema.org/a/153014.png)](https://asciinema.org/a/153014)
+[![asciicast](https://asciinema.org/a/153014.png)](https://asciinema.org/a/153014)
 
 Thanks to Peter Nirschl for this great work!
 

src/libs/tools/src/backend.cpp

@@ -111,10 +111,10 @@ void Backend::setMountpoint (Key mountpoint, KeySet mountConf)
 			alreadyUsedMountpoints.push_back (Key ("user" + name, KEY_END).getName ());
 			alreadyUsedMountpoints.push_back (Key ("system" + name, KEY_END).getName ());
 		}
-		else
-		{
-			alreadyUsedMountpoints.push_back (name);
-		}
+
+		// always add name itself, too
+		alreadyUsedMountpoints.push_back (name);
+
 		namesAsString += name;
 		namesAsString += " ";
 	}
@@ -142,6 +142,11 @@ void Backend::setMountpoint (Key mountpoint, KeySet mountConf)
 	// STEP 3: check for name match
 	if (smp == "/")
 	{
+		if (std::find (alreadyUsedMountpoints.begin (), alreadyUsedMountpoints.end (), "/") != alreadyUsedMountpoints.end ())
+		{
+			throw MountpointAlreadyInUseException (
+				"Root mountpoint not possible, because the root mountpoint already exists.\n");
+		}
 		Key specmp ("spec", KEY_END);
 		if (std::find (alreadyUsedMountpoints.begin (), alreadyUsedMountpoints.end (), specmp.getName ()) !=
 		    alreadyUsedMountpoints.end ())
@@ -169,6 +174,11 @@ void Backend::setMountpoint (Key mountpoint, KeySet mountConf)
 	}
 	else if (smp.at (0) == '/')
 	{
+		if (std::find (alreadyUsedMountpoints.begin (), alreadyUsedMountpoints.end (), smp) != alreadyUsedMountpoints.end ())
+		{
+			throw MountpointAlreadyInUseException ("Cascading mountpoint " + smp +
+							       " not possible, because cascading mountpoint " + smp + " already exists.\n");
+		}
 		Key dkmp ("dir" + smp, KEY_END);
 		if (std::find (alreadyUsedMountpoints.begin (), alreadyUsedMountpoints.end (), dkmp.getName ()) !=
 		    alreadyUsedMountpoints.end ())

src/plugins/dini/dini.c

@@ -20,6 +20,7 @@ int elektraDiniOpen (Plugin * handle, Key * errorKey ELEKTRA_UNUSED)
 	dini->iniConfig = ksDup (elektraPluginGetConfig (handle));
 	dini->dump = elektraInvokeOpen ("dump", dini->dumpConfig);
 	dini->ini = elektraInvokeOpen ("ini", dini->iniConfig);
+	dini->bin = elektraInvokeOpen ("binary", dini->iniConfig);
 
 	dini->dumpErrors = keyNew ("", KEY_END);
 
@@ -32,6 +33,7 @@ int elektraDiniClose (Plugin * handle, Key * errorKey ELEKTRA_UNUSED)
 {
 	Dini * dini = elektraPluginGetData (handle);
 
+	elektraInvokeClose (dini->bin);
 	elektraInvokeClose (dini->ini);
 	elektraInvokeClose (dini->dump);
 
@@ -73,14 +75,26 @@ int elektraDiniGet (Plugin * handle, KeySet * returned, Key * parentKey)
 		return ELEKTRA_PLUGIN_STATUS_SUCCESS;
 	}
 
-	return elektraInvoke2Args (dini->ini, "get", returned, parentKey);
+	int ret = elektraInvoke2Args (dini->ini, "get", returned, parentKey);
+	if (dini->bin)
+	{
+		ret |= elektraInvoke2Args (dini->bin, "get", returned, parentKey); // postgetstorage
+	}
+	return ret;
 }
 
 int elektraDiniSet (Plugin * handle ELEKTRA_UNUSED, KeySet * returned ELEKTRA_UNUSED, Key * parentKey ELEKTRA_UNUSED)
 {
 	// set all keys
 	Dini * dini = elektraPluginGetData (handle);
-	return elektraInvoke2Args (dini->ini, "set", returned, parentKey);
+
+	int ret = 0;
+	if (dini->bin)
+	{
+		elektraInvoke2Args (dini->bin, "set", returned, parentKey); // presetstorage
+	}
+	ret |= elektraInvoke2Args (dini->ini, "set", returned, parentKey);
+	return ret;
 }
 
 Plugin * ELEKTRA_PLUGIN_EXPORT (dini)

src/plugins/dini/dini.h

@@ -26,6 +26,7 @@ typedef struct
 	KeySet * modules;
 	ElektraInvokeHandle * dump;
 	ElektraInvokeHandle * ini;
+	ElektraInvokeHandle * bin;
 	KeySet * dumpConfig;
 	KeySet * iniConfig;
 	Key * dumpErrors;

src/tools/kdb/mount.cpp

@@ -14,6 +14,8 @@
 #include <cmdline.hpp>
 #include <mount.hpp>
 
+#include <keysetio.hpp>
+
 #include <fstream>
 #include <iostream>
 #include <iterator>
@@ -101,6 +103,15 @@ void MountCommand::buildBackend (Cmdline const & cl)
 		throw invalid_argument (mp + " is not a valid mountpoint");
 	}
 
+	KeySet dupMountConf = mountConf.dup ();
+
+	if (cl.force || cl.strategy != "preserve")
+	{
+		Key cutKey (Backends::mountpointsPath, KEY_END);
+		cutKey.addBaseName (mpk.getName ());
+		mountConf.cut (cutKey);
+	}
+
 	backend.setMountpoint (mpk, mountConf);
 
 	backend.setBackendConfig (cl.getPluginsConfig ("system/"));
@@ -161,6 +172,29 @@ void MountCommand::buildBackend (Cmdline const & cl)
 	// Call it a day
 	outputMissingRecommends (backend.resolveNeeds (cl.withRecommends));
 	backend.serialize (mountConf);
+
+	if (cl.strategy == "unchanged" && cl.debug)
+	{
+		cout << "The new configuration is:" << endl;
+		std::cout << mountConf;
+		std::cout << "------------------------" << std::endl;
+		cout << "The configuration originally was:" << endl;
+		std::cout << dupMountConf;
+	}
+
+	if (!cl.force && (cl.strategy == "unchanged" && mountConf != dupMountConf))
+	{
+		// throw error because it is not unchanged
+		try
+		{
+			backend.setMountpoint (mpk, dupMountConf);
+		}
+		catch (MountpointAlreadyInUseException const & e)
+		{
+			throw MountpointAlreadyInUseException (
+				std::string ("Requested unchanged mountpoint but mount would lead to changes\n") + e.what ());
+		}
+	}
 }
 
 void MountCommand::readPluginConfig (KeySet & pluginConfig)

src/tools/kdb/mount.hpp

@@ -35,7 +35,7 @@ class MountCommand : public MountBaseCommand
 
 	virtual std::string getShortOptions () override
 	{
-		return "dqiR0123cW";
+		return "dfqisR0123cW";
 	}
 
 	virtual std::string getSynopsis () override

src/tools/kdb/mountbase.cpp

@@ -69,15 +69,7 @@ void MountBaseCommand::getMountpoint (Cmdline const & cl)
 	{
 		if (cur.getBaseName () == "mountpoint")
 		{
-			if (cur.getString ().at (0) == '/')
-			{
-				mountpoints.push_back (Key ("user" + cur.getString (), KEY_END).getName ());
-				mountpoints.push_back (Key ("system" + cur.getString (), KEY_END).getName ());
-			}
-			else
-			{
-				mountpoints.push_back (cur.getString ());
-			}
+			mountpoints.push_back (cur.getString ());
 		};
 	}