ifparse: add skeleton

Makefile

@@ -74,6 +74,13 @@ MULTICALL_${CONFIG_IFCTRSTAT}_OBJ += ${IFCTRSTAT_SRC:.c=.o}
 CMDS_${CONFIG_IFCTRSTAT} += ifctrstat
 CPPFLAGS_${CONFIG_IFCTRSTAT} += -DCONFIG_IFCTRSTAT
 
+# enable ifparse applet (+1 KB)
+CONFIG_IFPARSE ?= Y
+IFPARSE_SRC = cmd/ifparse.c
+MULTICALL_${CONFIG_IFPARSE}_OBJ += ${IFPARSE_SRC:.c=.o}
+CMDS_${CONFIG_IFPARSE} += ifparse
+CPPFLAGS_${CONFIG_IFPARSE} += -DCONFIG_IFPARSE
+
 MULTICALL_OBJ += ${MULTICALL_Y_OBJ}
 CMDS += ${CMDS_Y}
 CPPFLAGS += ${CPPFLAGS_Y}

cmd/ifparse.c

@@ -0,0 +1,138 @@
+/*
+ * cmd/ifparse.c
+ * Purpose: Redisplay /e/n/i in alternative formats.
+ *
+ * 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.
+ */
+
+#define _GNU_SOURCE
+#include <fnmatch.h>
+#include <stdio.h>
+#include <string.h>
+#include <getopt.h>
+#include "libifupdown/libifupdown.h"
+#include "cmd/multicall.h"
+#include "cmd/pretty-print-iface.h"
+
+static bool show_all = false;
+static bool allow_undefined = false;
+
+static void
+set_show_all(const char *arg)
+{
+	(void) arg;
+
+	show_all = true;
+}
+
+static void
+set_allow_undefined(const char *arg)
+{
+	(void) arg;
+
+	allow_undefined = true;
+}
+
+static struct if_option local_options[] = {
+	{'A', "all", NULL, "show all interfaces", false, set_show_all},
+	{'U', "allow-undefined", NULL, "allow querying undefined (virtual) interfaces", false, set_allow_undefined},
+};
+
+static struct if_option_group local_option_group = {
+	.desc = "Program-specific options",
+	.group_size = ARRAY_SIZE(local_options),
+	.group = local_options
+};
+
+int
+ifparse_main(int argc, char *argv[])
+{
+	struct lif_dict state = {};
+	struct lif_dict collection = {};
+	struct lif_interface_file_parse_state parse_state = {
+		.collection = &collection,
+	};
+
+	lif_interface_collection_init(&collection);
+
+	if (!lif_state_read_path(&state, exec_opts.state_file))
+	{
+		fprintf(stderr, "%s: could not parse %s\n", argv0, exec_opts.state_file);
+		return EXIT_FAILURE;
+	}
+
+	if (!lif_interface_file_parse(&parse_state, exec_opts.interfaces_file))
+	{
+		fprintf(stderr, "%s: could not parse %s\n", argv0, exec_opts.interfaces_file);
+		return EXIT_FAILURE;
+	}
+
+	if (match_opts.property == NULL && lif_lifecycle_count_rdepends(&exec_opts, &collection) == -1)
+	{
+		fprintf(stderr, "%s: could not validate dependency tree\n", argv0);
+		return EXIT_FAILURE;
+	}
+
+	if (!lif_compat_apply(&collection))
+	{
+		fprintf(stderr, "%s: failed to apply compatibility glue\n", argv0);
+		return EXIT_FAILURE;
+	}
+
+	if (show_all)
+	{
+		struct lif_node *n;
+
+		LIF_DICT_FOREACH(n, &collection)
+		{
+			struct lif_dict_entry *entry = n->data;
+
+			prettyprint_interface_eni(entry->data);
+		}
+
+		return EXIT_SUCCESS;
+	}
+
+	if (optind >= argc)
+		generic_usage(self_applet, EXIT_FAILURE);
+
+	int idx = optind;
+	for (; idx < argc; idx++)
+	{
+		struct lif_dict_entry *entry = lif_dict_find(&collection, argv[idx]);
+		struct lif_interface *iface = NULL;
+
+		if (entry != NULL)
+			iface = entry->data;
+
+		if (entry == NULL && allow_undefined)
+			iface = lif_interface_collection_find(&collection, argv[idx]);
+
+		if (iface == NULL)
+		{
+			fprintf(stderr, "%s: unknown interface %s\n", argv0, argv[idx]);
+			return EXIT_FAILURE;
+		}
+
+		prettyprint_interface_eni(iface);
+	}
+
+	return EXIT_SUCCESS;
+}
+
+struct if_applet ifparse_applet = {
+	.name = "ifparse",
+	.desc = "redisplay interface configuration",
+	.main = ifparse_main,
+	.usage = "ifparse [options] <interfaces>\n  ifquery [options] --all",
+	.manpage = "8 ifparse",
+	.groups = { &global_option_group, &match_option_group, &exec_option_group, &local_option_group },
+};

cmd/multicall.c

@@ -36,6 +36,10 @@ extern struct if_applet ifdown_applet;
 extern struct if_applet ifctrstat_applet;
 #endif
 
+#ifdef CONFIG_IFPARSE
+extern struct if_applet ifparse_applet;
+#endif
+
 struct if_applet ifupdown_applet;
 const struct if_applet *self_applet = NULL;
 
@@ -46,6 +50,9 @@ struct if_applet *applet_table[] = {
 #ifdef CONFIG_IFUPDOWN
 	&ifdown_applet,
 #endif
+#ifdef CONFIG_IFPARSE
+	&ifparse_applet,
+#endif
 #ifdef CONFIG_IFQUERY
 	&ifquery_applet,
 #endif