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

@@ -172,7 +172,8 @@ class Vfs::Rump_file_system : public File_system
 		 ** File_system interface **
 		 ***************************/
 
-		static char const *name() { return "rump"; }
+		static char const *name()   { return "rump"; }
+		char const *type() override { return "rump"; }
 
 
 		/*********************************

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

@@ -65,7 +65,8 @@ class Jitterentropy_file_system : public Vfs::Single_file_system
 				jent_entropy_collector_free(_ec_stir);
 		}
 
-		static char const *name() { return "jitterentropy"; }
+		static char const *name()   { return "jitterentropy"; }
+		char const *type() override { return "jitterentropy"; }
 
 
 		/********************************

repos/os/include/vfs/dir_file_system.h

@@ -562,7 +562,8 @@ class Vfs::Dir_file_system : public File_system
 		 ** File_system interface **
 		 ***************************/
 
-		char const *name() const { return "dir"; }
+		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

@@ -148,8 +148,8 @@ class Vfs::Block_file_system : public Single_file_system
 			destroy(_alloc, _block_buffer);
 		}
 
-		static char const *name() { return "block"; }
+		static char const *name()   { return "block"; }
-
+		char const *type() override { return "block"; }
 
 		/*********************************
 		 ** Directory service interface **

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

@@ -581,7 +581,8 @@ class Vfs::Fs_file_system : public File_system
 		 ** File_system interface **
 		 ***************************/
 
-		static char const *name() { return "fs"; }
+		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

@@ -41,8 +41,8 @@ class Vfs::Inline_file_system : public Single_file_system
 			_size(config.content_size())
 		{ }
 
-		static char const *name() { return "inline"; }
+		static char const *name()   { return "inline"; }
-
+		char const *type() override { return "inline"; }
 
 		/********************************
 		 ** Directory service interface **

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

@@ -58,8 +58,8 @@ class Vfs::Log_file_system : public Single_file_system
 			_log(_log_session(env))
 		{ }
 
-		static const char *name() { return "log"; }
+		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

@@ -30,8 +30,8 @@ struct Vfs::Null_file_system : Single_file_system
 		Single_file_system(NODE_TYPE_CHAR_DEVICE, name(), config)
 	{ }
 
-	static char const *name() { return "null"; }
+	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

@@ -786,7 +786,8 @@ class Vfs::Ram_file_system : public Vfs::File_system
 		 ** File_system interface **
 		 ***************************/
 
-		static char const *name() { return "ram"; }
+		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

@@ -58,8 +58,8 @@ class Vfs::Rom_file_system : public Single_file_system
 			_rom(env, _label.string)
 		{ }
 
-		static char const *name() { return "rom"; }
+		static char const *name()   { return "rom"; }
-
+		char const *type() override { return "rom"; }
 
 		/*********************************
 		 ** Directory-service interface **

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

@@ -39,8 +39,8 @@ class Vfs::Rtc_file_system : public Single_file_system
 			_rtc(env)
 		{ }
 
-		static char const *name() { return "rtc"; }
+		static char const *name()   { return "rtc"; }
-
+		char const *type() override { return "rtc"; }
 
 		/*********************************
 		 ** Directory-service interface **

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

@@ -40,8 +40,8 @@ class Vfs::Symlink_file_system : public Single_file_system
 			_target(config.attribute_value("target", Target()))
 		{ }
 
-		static char const *name() { return "symlink"; }
+		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 **
 		 *********************************/
@@ -574,7 +573,8 @@ class Vfs::Tar_file_system : public File_system
 		 ** File_system interface **
 		 ***************************/
 
-		static char const *name() { return "tar"; }
+		static char const *name()   { return "tar"; }
+		char const *type() override { return "tar"; }
 
 
 		/********************************

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

@@ -67,8 +67,8 @@ class Vfs::Terminal_file_system : public Single_file_system
 			_terminal.read_avail_sigh(_read_avail_handler);
 		}
 
-		static const char *name() { return "terminal"; }
+		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

@@ -30,8 +30,8 @@ struct Vfs::Zero_file_system : Single_file_system
 		Single_file_system(NODE_TYPE_CHAR_DEVICE, name(), config)
 	{ }
 
-	static char const *name() { return "zero"; }
+	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));
 		}
 };