vfs: dynamic configuration support

repos/dde_linux/run/lxip_http_srv.run

@@ -97,7 +97,7 @@ install_config $config
 # generic modules
 set boot_modules {
 	core ld.lib.so init timer
-	libc.lib.so lxip.lib.so test-lxip_http_srv libc_resolv.lib.so
+	libc.lib.so libm.lib.so lxip.lib.so test-lxip_http_srv libc_resolv.lib.so
 }
 
 # platform-specific modules

repos/dde_rump/src/lib/vfs/rump/vfs_rump.cc

@@ -173,6 +173,7 @@ class Vfs::Rump_file_system : public File_system
 		 ***************************/
 
 		static char const *name()   { return "rump"; }
+		char const *type() override { return "rump"; }
 
 
 		/*********************************

repos/libports/src/lib/vfs/jitterentropy/vfs_jitterentropy.h

@@ -66,6 +66,7 @@ class Jitterentropy_file_system : public Vfs::Single_file_system
 		}
 
 		static char const *name()   { return "jitterentropy"; }
+		char const *type() override { return "jitterentropy"; }
 
 
 		/********************************

repos/os/include/vfs/dir_file_system.h

@@ -563,6 +563,7 @@ class Vfs::Dir_file_system : public File_system
 		 ***************************/
 
 		char const *name() const    { return "dir"; }
+		char const *type() override { return "dir"; }
 
 		/**
 		 * Synchronize all file systems
@@ -583,6 +584,25 @@ class Vfs::Dir_file_system : public File_system
 				fs->sync(path);
 		}
 
+		void apply_config(Genode::Xml_node const &node) override
+		{
+			using namespace Genode;
+
+			File_system *curr = _first_file_system;
+			for (unsigned i = 0; i < node.num_sub_nodes(); i++, curr = curr->next) {
+				Xml_node const &sub_node = node.sub_node(i);
+
+				/* check if type of XML node matches current file-system type */
+				if (sub_node.has_type(curr->type()) == false) {
+					Genode::error("VFS config update failed (node type '",
+					               sub_node.type(), "' != fs type '", curr->type(),"')");
+					return;
+				}
+
+				curr->apply_config(node.sub_node(i));
+			}
+		}
+
 
 		/********************************
 		 ** File I/O service interface **

repos/os/include/vfs/file_system.h

@@ -35,6 +35,16 @@ struct Vfs::File_system : Directory_service, File_io_service
 	 * This method flushes any delayed operations from the file system.
 	 */
 	virtual void sync(char const *path) { }
+
+	/**
+	 * Adjust to configuration changes
+	 */
+	virtual void apply_config(Genode::Xml_node const &node) { }
+
+	/**
+	 * Return the file-system type
+	 */
+	virtual char const *type() = 0;
 };
 
 #endif /* _INCLUDE__VFS__FILE_SYSTEM_H_ */

repos/os/src/lib/vfs/block_file_system.h

@@ -149,7 +149,7 @@ class Vfs::Block_file_system : public Single_file_system
 		}
 
 		static char const *name()   { return "block"; }
-
+		char const *type() override { return "block"; }
 
 		/*********************************
 		 ** Directory service interface **

repos/os/src/lib/vfs/fs_file_system.h

@@ -582,6 +582,7 @@ class Vfs::Fs_file_system : public File_system
 		 ***************************/
 
 		static char const *name()   { return "fs"; }
+		char const *type() override { return "fs"; }
 
 		void sync(char const *path) override
 		{

repos/os/src/lib/vfs/inline_file_system.h

@@ -42,7 +42,7 @@ class Vfs::Inline_file_system : public Single_file_system
 		{ }
 
 		static char const *name()   { return "inline"; }
-
+		char const *type() override { return "inline"; }
 
 		/********************************
 		 ** Directory service interface **

repos/os/src/lib/vfs/log_file_system.h

@@ -59,7 +59,7 @@ class Vfs::Log_file_system : public Single_file_system
 		{ }
 
 		static const char *name()   { return "log"; }
-
+		char const *type() override { return "log"; }
 
 		/********************************
 		 ** File I/O service interface **

repos/os/src/lib/vfs/null_file_system.h

@@ -31,7 +31,7 @@ struct Vfs::Null_file_system : Single_file_system
 	{ }
 
 	static char const *name()   { return "null"; }
-
+	char const *type() override { return "null"; }
 
 	/********************************
 	 ** File I/O service interface **

repos/os/src/lib/vfs/ram_file_system.h

@@ -787,6 +787,7 @@ class Vfs::Ram_file_system : public Vfs::File_system
 		 ***************************/
 
 		static char const *name()   { return "ram"; }
+		char const *type() override { return "ram"; }
 };
 
 #endif /* _INCLUDE__VFS__RAM_FILE_SYSTEM_H_ */

repos/os/src/lib/vfs/rom_file_system.h

@@ -59,7 +59,7 @@ class Vfs::Rom_file_system : public Single_file_system
 		{ }
 
 		static char const *name()   { return "rom"; }
-
+		char const *type() override { return "rom"; }
 
 		/*********************************
 		 ** Directory-service interface **

repos/os/src/lib/vfs/rtc_file_system.h

@@ -40,7 +40,7 @@ class Vfs::Rtc_file_system : public Single_file_system
 		{ }
 
 		static char const *name()   { return "rtc"; }
-
+		char const *type() override { return "rtc"; }
 
 		/*********************************
 		 ** Directory-service interface **

repos/os/src/lib/vfs/symlink_file_system.h

@@ -41,7 +41,7 @@ class Vfs::Symlink_file_system : public Single_file_system
 		{ }
 
 		static char const *name()   { return "symlink"; }
-
+		char const *type() override { return "symlink"; }
 
 		/*********************************
 		 ** Directory-service interface **

repos/os/src/lib/vfs/tar_file_system.h

@@ -358,7 +358,6 @@ class Vfs::Tar_file_system : public File_system
 			_for_each_tar_record_do(Add_node_action(_alloc, _root_node));
 		}
 
-
 		/*********************************
 		 ** Directory-service interface **
 		 *********************************/
@@ -575,6 +574,7 @@ class Vfs::Tar_file_system : public File_system
 		 ***************************/
 
 		static char const *name()   { return "tar"; }
+		char const *type() override { return "tar"; }
 
 
 		/********************************

repos/os/src/lib/vfs/terminal_file_system.h

@@ -68,7 +68,7 @@ class Vfs::Terminal_file_system : public Single_file_system
 		}
 
 		static const char *name()   { return "terminal"; }
-
+		char const *type() override { return "terminal"; }
 
 		/********************************
 		 ** File I/O service interface **

repos/os/src/lib/vfs/zero_file_system.h

@@ -31,7 +31,7 @@ struct Vfs::Zero_file_system : Single_file_system
 	{ }
 
 	static char const *name()   { return "zero"; }
-
+	char const *type() override { return "zero"; }
 
 	/********************************
 	 ** File I/O service interface **

repos/os/src/server/vfs/main.cc

@@ -500,6 +500,15 @@ class Vfs_server::Root :
 			_env, _heap, vfs_config(), _io_response_handler,
 			Vfs::global_file_system_factory() };
 
+		Genode::Signal_handler<Root> _config_dispatcher {
+			_env.ep(), *this, &Root::_config_update };
+
+		void _config_update()
+		{
+			_config_rom.update();
+			_vfs.apply_config(vfs_config());
+		}
+
 	protected:
 
 		Session_component *_create_session(const char *args) override
@@ -603,6 +612,7 @@ class Vfs_server::Root :
 			Root_component<Session_component>(&env.ep().rpc_ep(), &md_alloc),
 			_env(env)
 		{
+			_config_rom.sigh(_config_dispatcher);
 			env.parent().announce(env.ep().manage(*this));
 		}
 };