Merge pull request #78 from ifupdown-ng/feature/preferences

config file support

Makefile

@@ -10,6 +10,7 @@ PACKAGE_BUGREPORT := https://github.com/ifupdown-ng/ifupdown-ng/issues/new
 
 INTERFACES_FILE := /etc/network/interfaces
 STATE_FILE := /run/ifstate
+CONFIG_FILE := /etc/network/ifupdown-ng.conf
 EXECUTOR_PATH := /usr/libexec/ifupdown-ng
 
 CFLAGS ?= -ggdb3 -Os
@@ -18,6 +19,7 @@ CFLAGS += ${LIBBSD_CFLAGS}
 CPPFLAGS = -I.
 CPPFLAGS += -DINTERFACES_FILE=\"${INTERFACES_FILE}\"
 CPPFLAGS += -DSTATE_FILE=\"${STATE_FILE}\"
+CPPFLAGS += -DCONFIG_FILE=\"${CONFIG_FILE}\"
 CPPFLAGS += -DPACKAGE_NAME=\"${PACKAGE_NAME}\"
 CPPFLAGS += -DPACKAGE_VERSION=\"${PACKAGE_VERSION}\"
 CPPFLAGS += -DPACKAGE_BUGREPORT=\"${PACKAGE_BUGREPORT}\"
@@ -34,7 +36,9 @@ LIBIFUPDOWN_SRC = \
 	libifupdown/state.c \
 	libifupdown/environment.c \
 	libifupdown/execute.c \
-	libifupdown/lifecycle.c
+	libifupdown/lifecycle.c \
+	libifupdown/config-parser.c \
+	libifupdown/config-file.c
 
 LIBIFUPDOWN_OBJ = ${LIBIFUPDOWN_SRC:.c=.o}
 LIBIFUPDOWN_LIB = libifupdown.a
@@ -125,6 +129,7 @@ install: all
 	for i in ${EXECUTOR_SCRIPTS_STUB}; do \
 		install -D -m755 executor-scripts/stub/$$i ${DESTDIR}${EXECUTOR_PATH}/$$i; \
 	done
+	install -D -m644 dist/ifupdown-ng.conf.example ${DESTDIR}${CONFIG_FILE}.example
 
 .scd.1 .scd.2 .scd.3 .scd.4 .scd.5 .scd.6 .scd.7 .scd.8:
 	${SCDOC} < $< > $@

cmd/multicall.c

@@ -72,6 +72,8 @@ main(int argc, char *argv[])
 	argv0 = basename(argv[0]);
 	const struct if_applet **app;
 
+	lif_config_load(CONFIG_FILE);
+
 	app = bsearch(argv0, applet_table,
 		      ARRAY_SIZE(applet_table), sizeof(*applet_table),
 		      applet_cmp);

dist/ifupdown-ng.conf.example

@@ -0,0 +1,10 @@
+# This is an example configuration file for ifupdown-ng, which allows
+# the system administrator to configure the behaviour of ifupdown-ng.
+#
+# The settings specified here are the defaults of ifupdown-ng.
+
+# allow_addon_scripts:
+# Enable support for /etc/if-X.d addon scripts.  These are used for
+# compatibility with legacy setups, and may be disabled for performance
+# improvements in setups where only ifupdown-ng executors are used.
+allow_addon_scripts = 1

libifupdown/config-file.c

@@ -0,0 +1,63 @@
+/*
+ * libifupdown/config-file.c
+ * Purpose: config file loading
+ *
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include "libifupdown/libifupdown.h"
+
+struct lif_config_file lif_config = {
+	.allow_addon_scripts = true,
+};
+
+static bool
+set_bool_value(const char *key, const char *value, void *opaque)
+{
+	(void) key;
+
+	if (*value == '1' ||
+		*value == 'Y' || *value == 'y' || 
+		*value == 'T' || *value == 't')
+		*(bool *) opaque = true;
+	else if (*value == '0' ||
+		*value == 'N' || *value == 'n' ||
+		*value == 'F' || *value == 'f')
+		*(bool *) opaque = false;
+	else
+		return false;
+
+	return true;
+}
+
+static struct lif_config_handler handlers[] = {
+	{"allow_addon_scripts", set_bool_value, &lif_config.allow_addon_scripts},
+};
+
+bool
+lif_config_load(const char *filename)
+{
+	FILE *fd = fopen(filename, "r");
+
+	if (fd == NULL)
+	{
+#if 0
+		fprintf(stderr, "ifupdown-ng: cannot open config %s: %s\n",
+			filename, strerror(errno));
+#endif
+		return false;
+	}
+
+	return lif_config_parse_file(fd, filename, handlers, ARRAY_SIZE(handlers));
+}

libifupdown/config-file.h

@@ -0,0 +1,29 @@
+/*
+ * libifupdown/config-file.h
+ * Purpose: config file loading
+ *
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#ifndef LIBIFUPDOWN__CONFIG_FILE_H
+#define LIBIFUPDOWN__CONFIG_FILE_H
+
+#include <stdbool.h>
+
+struct lif_config_file {
+	bool allow_addon_scripts;
+};
+
+extern struct lif_config_file lif_config;
+
+extern bool lif_config_load(const char *filename);
+
+#endif

libifupdown/config-parser.c

@@ -0,0 +1,87 @@
+/*
+ * libifupdown/config-parser.c
+ * Purpose: config parsing
+ *
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "libifupdown/config-parser.h"
+#include "libifupdown/fgetline.h"
+#include "libifupdown/tokenize.h"
+
+static int
+handler_cmp(const void *a, const void *b)
+{
+	const char *key = a;
+	const struct lif_config_handler *hdl = b;
+
+	return strcmp(key, hdl->key);
+}
+
+bool
+lif_config_parse_file(FILE *fd, const char *filename, struct lif_config_handler *handlers, size_t handler_count)
+{
+	char linebuf[4096];
+	size_t lineno = 0;
+
+	while (lif_fgetline(linebuf, sizeof linebuf, fd))
+	{
+		char *bufp = linebuf;
+		char *key = lif_next_token_eq(&bufp);
+		char *value = lif_next_token_eq(&bufp);
+
+		lineno++;
+
+		if (!*key || !*value)
+			continue;
+
+		if (*key == '#')
+			continue;
+
+		struct lif_config_handler *hdl = bsearch(key, handlers, handler_count, sizeof(*handlers),
+			handler_cmp);
+
+		if (hdl == NULL)
+		{
+			fprintf(stderr, "ifupdown-ng: %s:%zu: warning: unknown config setting %s\n",
+				filename, lineno, key);
+			continue;
+		}
+
+		if (!hdl->handle(key, value, hdl->opaque))
+		{
+			fclose(fd);
+			return false;
+		}
+	}
+
+	fclose(fd);
+	return true;
+}
+
+bool
+lif_config_parse(const char *filename, struct lif_config_handler *handlers, size_t handler_count)
+{
+	FILE *f = fopen(filename, "r");
+
+	if (f == NULL)
+	{
+		fprintf(stderr, "ifupdown-ng: unable to parse %s: %s\n", filename, strerror(errno));
+		return false;
+	}
+
+	return lif_config_parse_file(f, filename, handlers, handler_count);
+}

libifupdown/config-parser.h

@@ -0,0 +1,32 @@
+/*
+ * libifupdown/config-parser.h
+ * Purpose: config parsing
+ *
+ * Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * This software is provided 'as is' and without any warranty, express or
+ * implied.  In no event shall the authors be liable for any damages arising
+ * from the use of this software.
+ */
+
+#ifndef LIBIFUPDOWN__CONFIG_PARSER_H
+#define LIBIFUPDOWN__CONFIG_PARSER_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+
+struct lif_config_handler {
+	const char *key;
+	bool (*handle)(const char *key, const char *value, void *opaque);
+	void *opaque;
+};
+
+extern bool lif_config_parse_file(FILE *f, const char *filename, struct lif_config_handler *handlers, size_t handler_count);
+extern bool lif_config_parse(const char *filename, struct lif_config_handler *handlers, size_t handler_count);
+
+#endif

libifupdown/libifupdown.h

@@ -27,6 +27,8 @@
 #include "libifupdown/execute.h"
 #include "libifupdown/lifecycle.h"
 #include "libifupdown/tokenize.h"
+#include "libifupdown/config-file.h"
+#include "libifupdown/config-parser.h"
 
 #ifndef ARRAY_SIZE
 # define ARRAY_SIZE(x)   (sizeof(x) / sizeof(*x))

libifupdown/lifecycle.c

@@ -25,6 +25,7 @@
 #include "libifupdown/lifecycle.h"
 #include "libifupdown/state.h"
 #include "libifupdown/tokenize.h"
+#include "libifupdown/config-file.h"
 
 static bool
 handle_commands_for_phase(const struct lif_execute_opts *opts, char *const envp[], const struct lif_interface *iface, const char *phase)
@@ -240,6 +241,10 @@ lif_lifecycle_run_phase(const struct lif_execute_opts *opts, struct lif_interfac
 	if (!handle_commands_for_phase(opts, envp, iface, phase))
 		goto handle_error;
 
+	/* if we don't need to support /etc/if-X.d we're done here */
+	if (!lif_config.allow_addon_scripts)
+		goto out_free;
+
 	/* Check if scripts dir for this phase is present and bail out if it isn't */
 	struct stat dir_stat;
 	char dir_path[4096];

libifupdown/tokenize.h

@@ -18,6 +18,24 @@
 
 #include <ctype.h>
 
+static inline char *
+lif_next_token_eq(char **buf)
+{
+	char *out = *buf;
+
+	while (*out && (isspace(*out) || *out == '='))
+		out++;
+
+	char *end = out;
+	while (*end && !isspace(*end) && *end != '=')
+		end++;
+
+	*end++ = '\0';
+	*buf = end;
+
+	return out;
+}
+
 static inline char *
 lif_next_token(char **buf)
 {