Plugins configuration files

etc/Makefile.am

@@ -6,6 +6,7 @@ EXTRA_DIST = mptcpd.conf.in
 
 pkgsysconf_DATA = mptcpd.conf
 pkgsysconfdir = $(sysconfdir)/@PACKAGE@
+pluginsconfdir = $(pkgsysconfdir)/plugins.conf.d
 
 ## The configure script won't fully expand $pkglibdir so leverage
 ## `make' based variable expansion instead.
@@ -27,8 +28,11 @@ CLEANFILES = mptcpd.conf
 # writable.
 install-data-hook: installcheck-local
 	chmod o-w $(DESTDIR)$(pkgsysconfdir)
+	mkdir -p $(DESTDIR)$(pluginsconfdir)
+	chmod o-w $(DESTDIR)$(pluginsconfdir)
 
 installcheck-local:
-	$(top_srcdir)/scripts/check-permissions \
-		$(DESTDIR)$(pkgsysconfdir) \
-		$(DESTDIR)$(pkgsysconfdir)/mptcpd.conf
+	$(top_srcdir)/scripts/check-permissions 	\
+		$(DESTDIR)$(pkgsysconfdir) 		\
+		$(DESTDIR)$(pkgsysconfdir)/mptcpd.conf  \
+		$(DESTDIR)$(pluginsconfdir)

include/mptcpd/plugin.h

@@ -345,6 +345,10 @@ MPTCPD_API bool mptcpd_plugin_register_ops(
         char const *name,
         struct mptcpd_plugin_ops const *ops);
 
+MPTCPD_API bool mptcpd_plugin_read_config(char const *filename,
+                                          mptcpd_parse_func_t fun,
+                                          void *user_data);
+
 #ifdef __cplusplus
 }
 #endif

include/mptcpd/private/configuration.h

@@ -10,6 +10,8 @@
 #ifndef MPTCPD_CONFIGURATION_H
 #define MPTCPD_CONFIGURATION_H
 
+#include <mptcpd/export.h>
+#include <mptcpd/types.h>
 
 /**
  * Function pointer corresponding to the ELL functions that set the
@@ -66,6 +68,9 @@ struct mptcpd_config
 
         /// A list of plugins to load.
         struct l_queue *plugins_to_load;
+
+        /// Location of mptcpd plugins configuration files
+        char *plugins_conf_dir;
 };
 
 /**
@@ -87,6 +92,10 @@ struct mptcpd_config *mptcpd_config_create(int argc, char *argv[]);
  */
 void mptcpd_config_destroy(struct mptcpd_config *config);
 
+MPTCPD_API bool mptcpd_config_read(char const *filename,
+                                   mptcpd_parse_func_t fun,
+                                   void *user_data);
+
 #endif  // MPTCPD_CONFIGURATION_H
 
 /*

include/mptcpd/private/plugin.h

@@ -42,6 +42,7 @@ struct mptcpd_interface;
  */
 MPTCPD_API bool mptcpd_plugin_load(char const *dir,
                                    char const *default_name,
+                                   char const *plugins_conf_dir,
                                    struct l_queue const *plugins_to_load,
                                    struct mptcpd_pm *pm);
 

include/mptcpd/types.h

@@ -12,6 +12,7 @@
 
 #include <stddef.h>
 #include <inttypes.h>
+#include <ell/settings.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -162,6 +163,10 @@ typedef void (*mptcpd_pm_get_limits_cb)(
         size_t len,
         void *callback_data);
 
+typedef void (*mptcpd_parse_func_t) (
+        struct l_settings *const settings,
+        void *user_data);
+
 #ifdef __cplusplus
 }
 #endif

lib/Makefile.am

@@ -20,6 +20,7 @@ libmptcpd_la_LDFLAGS = 	\
 
 libmptcpd_la_SOURCES =		\
 	addr_info.c		\
+	configuration.c		\
 	id_manager.c		\
 	network_monitor.c	\
 	path_manager.c		\

lib/configuration.c

@@ -0,0 +1,84 @@
+#include <stdlib.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <assert.h>
+#include <sys/stat.h>
+#include <errno.h>
+
+#include <ell/log.h>
+#include <ell/util.h>
+#include <ell/settings.h>
+
+#include <mptcpd/types.h>
+
+#include <mptcpd/private/configuration.h>
+
+/**
+ * @brief Verify file permissions are secure.
+ *
+ * Mptcpd requires that its files are only writable by the owner and
+ * group.  Verify that the "other" write mode, @c S_IWOTH, isn't set.
+ *
+ * @param[in] f Name of file to check for expected permissions.
+ *
+ * @note There is a TOCTOU race condition between this file
+ *       permissions check and subsequent calls to functions that
+ *       access the given file @a f, such as the call to
+ *       @c l_settings_load_from_file().  There is currently no way
+ *       to avoid that with the existing ELL API.
+ */
+static bool check_file_perms(char const *f)
+{
+        struct stat sb;
+        bool perms_ok = false;
+
+        if (stat(f, &sb) == 0) {
+                perms_ok = S_ISREG(sb.st_mode)
+                           && (sb.st_mode & S_IWOTH) == 0;
+
+                if (!perms_ok)
+                        l_error("\"%s\" should be a file that is not "
+                                "world writable.",
+                                f);
+        } else if (errno == ENOENT) {
+                perms_ok = true;
+
+                l_debug("File \"%s\" does not exist.", f);
+        } else {
+                l_debug("Unexpected error during file "
+                        "permissions check.");
+        }
+
+        return perms_ok;
+}
+
+bool mptcpd_config_read(char const *filename,
+                        mptcpd_parse_func_t fun,
+                        void *user_data)
+{
+        assert(filename != NULL);
+        assert(fun != NULL);
+
+        if (!check_file_perms(filename))
+                return false;
+
+        struct l_settings *const settings = l_settings_new();
+        if (settings == NULL) {
+                l_error("Unable to create mptcpd settings.");
+
+                return false;
+        }
+
+        bool success = l_settings_load_from_file(settings, filename);
+
+        if (success)
+                fun(settings, user_data);
+        else
+                l_debug("Unable to load mptcpd settings from file '%s'",
+                        filename);
+
+        l_settings_free(settings);
+
+        return success;
+}
+

lib/plugin.c

@@ -39,6 +39,7 @@
 # define MPTCP_PM_NAME_LEN GENL_NAMSIZ
 #endif
 
+#include <mptcpd/private/configuration.h>
 #include <mptcpd/private/plugin.h>
 #include <mptcpd/plugin.h>
 
@@ -86,6 +87,8 @@ static char _default_name[MPTCP_PM_NAME_LEN + 1];
  */
 static struct mptcpd_plugin_ops const *_default_ops;
 
+static char *_conf_dir;
+
 // ----------------------------------------------------------------
 //                      Implementation Details
 // ----------------------------------------------------------------
@@ -432,6 +435,7 @@ static void unload_plugins(struct mptcpd_pm *pm)
 
 bool mptcpd_plugin_load(char const *dir,
                         char const *default_name,
+                        char const *plugins_conf_dir,
                         struct l_queue const *plugins_to_load,
                         struct mptcpd_pm *pm)
 {
@@ -440,6 +444,14 @@ bool mptcpd_plugin_load(char const *dir,
                 return false;
         }
 
+        if (plugins_conf_dir == NULL) {
+                l_error("No plugins configuration directory specified.");
+                return false;
+        }
+
+        if (_conf_dir == NULL)
+                _conf_dir = l_strdup(plugins_conf_dir);
+
         if (_plugin_infos == NULL)
                 _plugin_infos = l_queue_new();
 
@@ -569,6 +581,25 @@ bool mptcpd_plugin_register_ops(char const *name,
         return registered;
 }
 
+bool mptcpd_plugin_read_config(char const *filename,
+                               mptcpd_parse_func_t fun,
+                               void *user_data)
+{
+        assert(filename != NULL);
+        assert(fun != NULL);
+
+        char *const path = l_strdup_printf("%s/%s.conf",
+                                           _conf_dir,
+                                           filename);
+
+        bool success = mptcpd_config_read(path, fun, user_data);
+
+        l_free(path);
+
+        return success;
+}
+
+
 // ----------------------------------------------------------------
 //               Plugin Operation Callback Invocation
 // ----------------------------------------------------------------

src/Makefile.am

@@ -32,10 +32,12 @@ libpath_manager_la_LIBADD =			\
 	$(top_builddir)/lib/libmptcpd.la	\
 	$(ELL_LIBS) $(CODE_COVERAGE_LIBS)
 
-libpath_manager_la_CPPFLAGS =	\
-	$(AM_CPPFLAGS)		\
+libpath_manager_la_CPPFLAGS =						\
+	$(AM_CPPFLAGS)							\
 	-DMPTCPD_CONFIG_FILE='"$(sysconfdir)/@PACKAGE@/@[email protected]"' \
-	-DMPTCPD_DEFAULT_PLUGINDIR='"$(libdir)/@PACKAGE@"'
+	-DMPTCPD_DEFAULT_PLUGINDIR='"$(libdir)/@PACKAGE@"' 		\
+	-DMPTCPD_DEFAULT_PLUGINSCONFDIR='"$(sysconfdir)/@PACKAGE@/$\
+					 plugins.conf.d/"'
 
 EXTRA_DIST = mptcp.service.in