discover: Add configuration events & DHCP handler

This change adds a new event type, EVENT_ACTION_CONF. These events
supply a new configuration URL that petitiboot should download and
parse.

With this in place, we can receive DHCP configuration events.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

5 files changed, 111 insertions, 2 deletions

diff --git a/discover/device-handler.c b/discover/device-handler.c
index 6ff70c1..594a7c3 100644
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -451,6 +451,61 @@ static int handle_remove_user_event(struct device_handler *handler,
 	return 0;
 }
 
+static enum conf_method parse_conf_method(const char *str)
+{
+
+	if (!strcasecmp(str, "dhcp")) {
+		return CONF_METHOD_DHCP;
+	}
+	return CONF_METHOD_UNKNOWN;
+}
+
+static int handle_conf_user_event(struct device_handler *handler,
+		struct event *event)
+{
+	struct discover_context *ctx;
+	struct discover_device *dev;
+	enum conf_method method;
+	const char *val;
+
+	ctx = talloc(handler, struct discover_context);
+	ctx->event = event;
+	list_init(&ctx->boot_options);
+
+	val = event_get_param(event, "url");
+	if (!val) {
+		talloc_free(ctx);
+		return 0;
+	}
+
+	ctx->conf_url = pb_url_parse(ctx, val);
+	if (!ctx->conf_url) {
+		talloc_free(ctx);
+		return 0;
+	}
+
+	val = event_get_param(event, "method");
+	if (!val) {
+		talloc_free(ctx);
+		return 0;
+	}
+
+	method = parse_conf_method(val);
+	if (method == CONF_METHOD_UNKNOWN) {
+		talloc_free(ctx);
+		return 0;
+	}
+
+	dev = discover_device_create(handler, ctx, event);
+	ctx->device = dev;
+
+	iterate_parsers(ctx, method);
+
+	context_commit(handler, ctx);
+
+	return 0;
+}
+
 typedef int (*event_handler)(struct device_handler *, struct event *);
 
 static event_handler handlers[EVENT_TYPE_MAX][EVENT_ACTION_MAX] = {
@@ -461,6 +516,7 @@ static event_handler handlers[EVENT_TYPE_MAX][EVENT_ACTION_MAX] = {
 	[EVENT_TYPE_USER] = {
 		[EVENT_ACTION_ADD]	= handle_add_user_event,
 		[EVENT_ACTION_REMOVE]	= handle_remove_user_event,
+		[EVENT_ACTION_CONF]	= handle_conf_user_event,
 	}
 };
 
diff --git a/discover/device-handler.h b/discover/device-handler.h
index ad9f50a..f4c911e 100644
--- a/discover/device-handler.h
+++ b/discover/device-handler.h
@@ -14,6 +14,10 @@ struct device;
 enum conf_method {
 	CONF_METHOD_LOCAL_FILE,	/* discover by looking at local files on this
 				   block device */
+
+	CONF_METHOD_DHCP,	/* configuration from a DHCP response */
+
+	CONF_METHOD_UNKNOWN = -1,
 };
 
 struct discover_device {
@@ -48,6 +52,7 @@ struct discover_context {
 	struct event		*event;
 	struct discover_device	*device;
 	struct list		boot_options;
+	struct pb_url		*conf_url;
 	enum conf_method	method;
 };
 
diff --git a/discover/event.c b/discover/event.c
index 1314561..a05ce27 100644
--- a/discover/event.c
+++ b/discover/event.c
@@ -42,6 +42,8 @@ static int event_parse_ad_header(char *buf, int len, enum event_action *action,
 		*action = EVENT_ACTION_ADD;
 	else if (streq(buf, "remove"))
 		*action = EVENT_ACTION_REMOVE;
+	else if (streq(buf, "conf"))
+		*action = EVENT_ACTION_CONF;
 	else {
 		pb_log("%s: unknown action: %s\n", __func__, buf);
 		return -1;
diff --git a/discover/event.h b/discover/event.h
index 900ced8..70cc8fc 100644
--- a/discover/event.h
+++ b/discover/event.h
@@ -10,6 +10,7 @@ enum event_type {
 enum event_action {
 	EVENT_ACTION_ADD = 20,
 	EVENT_ACTION_REMOVE,
+	EVENT_ACTION_CONF,
 	EVENT_ACTION_MAX,
 };
 
diff --git a/discover/parser.c b/discover/parser.c
index c04a0af..42ee2e5 100644
--- a/discover/parser.c
+++ b/discover/parser.c
@@ -73,6 +73,28 @@ static char *local_path(struct discover_context *ctx,
 	return join_paths(ctx, ctx->device->mount_path, filename);
 }
 
+static int download_config(struct discover_context *ctx, char **buf, int *len)
+{
+	unsigned tempfile;
+	const char *file;
+	int rc;
+
+	file = load_url(ctx, ctx->conf_url, &tempfile);
+	if (!file)
+		return -1;
+
+	rc = read_file(ctx, file, buf, len);
+	if (rc)
+		goto out_clean;
+
+	return 0;
+
+out_clean:
+	if (tempfile)
+		unlink(file);
+	return -1;
+}
+
 static void iterate_parser_files(struct discover_context *ctx,
 		const struct parser *parser)
 {
@@ -100,11 +122,13 @@ static void iterate_parser_files(struct discover_context *ctx,
 
 void iterate_parsers(struct discover_context *ctx, enum conf_method method)
 {
-	int i;
+	int rc, i, len;
+	char *buf;
 
 	pb_log("trying parsers for %s\n", ctx->device->device->id);
 
-	if (method == CONF_METHOD_LOCAL_FILE) {
+	switch (method) {
+	case CONF_METHOD_LOCAL_FILE:
 		for (i = 0; i < n_parsers; i++) {
 			if (parsers[i]->method != CONF_METHOD_LOCAL_FILE)
 				continue;
@@ -114,6 +138,27 @@ void iterate_parsers(struct discover_context *ctx, enum conf_method method)
 			iterate_parser_files(ctx, ctx->parser);
 		}
 		ctx->parser = NULL;
+		break;
+
+	case CONF_METHOD_DHCP:
+		rc = download_config(ctx, &buf, &len);
+		if (rc)
+			return;
+
+		for (i = 0; i < n_parsers; i++) {
+			if (parsers[i]->method != method)
+				continue;
+
+			pb_log("\ttrying parser '%s'\n", parsers[i]->name);
+			ctx->parser = parsers[i];
+			parsers[i]->parse(ctx, buf, len);
+		}
+
+		break;
+
+	case CONF_METHOD_UNKNOWN:
+		break;
+
 	}
 }