services: herdd: implement scanning and parsing of runlevel and service config files

services/herdd/runlevel.c

@@ -0,0 +1,154 @@
+#include "runlevel.h"
+
+#include "log.h"
+#include "service.h"
+
+#include <errno.h>
+#include <fx/core/stringstream.h>
+#include <fx/ds/array.h>
+#include <fx/ds/dict.h>
+#include <fx/serial.h>
+#include <mango/log.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static struct queue runlevels = QUEUE_INIT;
+
+struct queue *global_runlevels(void)
+{
+	return &runlevels;
+}
+
+static int parse_runlevel_data(fx_object *in, struct runlevel *out)
+{
+	if (!fx_object_is_type(in, FX_TYPE_DICT)) {
+		return -1;
+	}
+
+	fx_dict *in_runlevel = fx_dict_at(in, "runlevel");
+	if (!in_runlevel || !fx_object_is_type(in_runlevel, FX_TYPE_DICT)) {
+		return -1;
+	}
+
+	fx_string *name = fx_dict_at(in_runlevel, "name");
+	if (!name || !fx_object_is_type(name, FX_TYPE_STRING)) {
+		return -1;
+	}
+
+	fx_string *description = fx_dict_at(in_runlevel, "description");
+	if (!description || !fx_object_is_type(description, FX_TYPE_STRING)) {
+		return -1;
+	}
+
+	fx_array *deps = fx_dict_at(in_runlevel, "requires");
+	if (deps && !fx_object_is_type(deps, FX_TYPE_ARRAY)) {
+		return -1;
+	}
+
+	int ret = 0;
+	size_t dep_count = fx_array_size(deps);
+	fx_iterator *it = fx_iterator_begin(deps);
+	fx_foreach_ptr(fx_string, dep, it)
+	{
+		if (!fx_object_is_type(dep, FX_TYPE_STRING)) {
+			ret = -1;
+			break;
+		}
+	}
+	fx_iterator_unref(it);
+
+	if (ret != 0) {
+		return ret;
+	}
+
+	out->rl_requires_count = dep_count;
+	out->rl_requires = calloc(dep_count, sizeof(char *));
+	it = fx_iterator_begin(deps);
+	size_t i = 0;
+	fx_foreach_ptr(fx_string, dep, it)
+	{
+		out->rl_requires[i++] = fx_string_steal(dep);
+	}
+	fx_iterator_unref(it);
+
+	out->rl_name = fx_string_steal(name);
+	out->rl_description = fx_string_steal(description);
+
+	return 0;
+}
+
+int runlevel_load(const char *path, struct runlevel **out)
+{
+	struct runlevel *rl = malloc(sizeof *rl);
+	if (!rl) {
+		errno = ENOMEM;
+		return -1;
+	}
+
+	FILE *fp = fopen(path, "r");
+	if (!fp) {
+		free(rl);
+		return -1;
+	}
+
+	fx_stream *in = fx_stream_open_fp(fp);
+	fx_serial_ctx *ctx = fx_toml_serial_ctx_create();
+	fx_object *data;
+	fx_status status = fx_serial_ctx_deserialise(ctx, in, &data, 0);
+	if (!FX_OK(status)) {
+		free(rl);
+		errno = EFTYPE;
+		return -1;
+	}
+
+	if (parse_runlevel_data(data, rl) != 0) {
+		free(rl);
+		errno = EFTYPE;
+		return -1;
+	}
+
+	fx_stream_unref(in);
+	fx_object_unref(data);
+
+	fclose(fp);
+
+	*out = rl;
+	return 0;
+}
+
+struct runlevel *runlevel_find(const char *name)
+{
+	struct queue_entry *cur = queue_first(&runlevels);
+	while (cur) {
+		struct runlevel *rl
+			= QUEUE_CONTAINER(struct runlevel, rl_entry, cur);
+		if (!strcmp(rl->rl_name, name)) {
+			return rl;
+		}
+
+		cur = queue_next(cur);
+	}
+
+	return NULL;
+}
+
+int runlevel_activate(struct runlevel *rl)
+{
+	for (size_t i = 0; i < rl->rl_requires_count; i++) {
+		const char *svc_name = rl->rl_requires[i];
+		struct service *svc = service_find(svc_name);
+		if (!svc) {
+			log_fail("Cannot find service %s.", svc_name);
+			return -1;
+		}
+
+		int ret = service_start(svc);
+		if (ret != 0) {
+			return ret;
+		}
+	}
+
+	log_ok("Reached runlevel %s.", rl->rl_description);
+	return 0;
+}