Load initial config file with the default values

For a full description please read here
eclipse-bluechi#147.
For each of the node types [hirte, agent] hirte
will get the default config from the default
files located in /usr/shar/hirte/{hirte|agent}
into the hashmap and only after that it will
get the custome config that the usr changed

Fixes: eclipse-bluechi#147
Signed-off-by: Artiom Divak <adivak@redhat.com>

.github/workflows/e2e.yaml

@@ -28,8 +28,8 @@ jobs:
           podman run --rm --name hirte-builder \
           -v  ${PWD}:/hirte:Z -it \
           registry.gitlab.com/centos/automotive/sample-images/hirte/hirte-builder:1.0.0 \
-          /bin/bash -c "rm -rf builddir; meson setup builddir; \
-          meson install -C builddir"
+          /bin/bash -c "rm -rf builddir; meson setup builddir -Dapi_bus=user; \
+          meson install -C builddir --destdir bin"
           podman build -f tests/Containerfile -t hirte-image .
 
       - name: run hirte containers

src/libhirte/common/cfg.c

@@ -98,7 +98,7 @@ int cfg_load_complete_configuration(
                 const char *custom_config_file,
                 const char *custom_config_directory) {
         int result = 0;
-        
+
         if (default_config_file != NULL) {
                 result = cfg_load_from_file(config, default_config_file);
                 if (result != 0) {

src/libhirte/common/cfg.h

@@ -0,0 +1,178 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+#include <stdbool.h>
+
+
+/*
+ * Existing configuration file options
+ */
+#define CFG_LOG_LEVEL "LogLevel"
+#define CFG_LOG_TARGET "LogTarget"
+#define CFG_LOG_IS_QUIET "LogIsQuiet"
+#define CFG_MANAGER_HOST "ManagerHost"
+#define CFG_MANAGER_PORT "ManagerPort"
+#define CFG_NODE_NAME "NodeName"
+#define CFG_ALLOWED_NODE_NAMES "AllowedNodeNames"
+
+/*
+ * Global section - this is used, when configuration options are specified in the configuration file
+ * without any section
+ */
+#define CFG_SECT_GLOBAL ""
+
+/*
+ * Configuration section for hirte manager.
+ */
+#define CFG_SECT_HIRTE "hirte"
+
+/*
+ * Configuration section for hirte agent.
+ */
+#define CFG_SECT_AGENT "hirte-agent"
+
+/*
+ * Structure holding the configuration
+ */
+typedef struct config config;
+
+/* Standard configuration file locations
+ */
+#define CFG_ETC_HIRTE_CONF CONFIG_H_SYSCONFDIR "/hirte/hirte.conf"
+#define CFG_ETC_HIRTE_AGENT_CONF CONFIG_H_SYSCONFDIR "/hirte/agent.conf"
+#define CFG_AGENT_DEFAULT_CONFIG "/usr/share/hirte-agent/config/hirte-default.conf"
+#define CFG_HIRTE_DEFAULT_CONFIG "/usr/share/hirte/config/hirte-default.conf"
+
+/*
+ * An item in a configuration map
+ */
+struct config_option {
+        char *section;
+        char *name;
+        char *value;
+};
+
+/*
+ * Initialize the application configuration object.
+ *
+ * Returns 0 if successful, otherwise standard error code
+ */
+int cfg_initialize(struct config **config);
+
+/*
+ * Dispose the application configuration object
+ */
+void cfg_dispose(struct config *config);
+
+/*
+ * Load the application configuration using standardized flow:
+ *
+ *   1. Load default configuration file
+ *   2. Load custom application configuration file, for example /etc/<NAME>.conf
+ *   3. Load custom application configuration directory, for example /etc/<NAME>.conf.d
+ *   4. Load configuration from environment variables
+ *
+ * WARNING: this method should be invoked only once after execution of config_initialize() to ensure
+ * standardized configuration loading flow is used.
+ *
+ * Returns 0 if successful, otherwise standard error code.
+ */
+int cfg_load_complete_configuration(
+                struct config *config,
+                const char *default_config_file,
+                const char *custom_config_file,
+                const char *custom_config_directory);
+
+/*
+ * Load the application configuration from the specified file and override any existing options values.
+ *
+ * Returns 0 if successful, otherwise standard error code.
+ */
+int cfg_load_from_file(struct config *config, const char *config_file);
+
+/*
+ * Load the application configuration from the predefined environment variables and override any existing
+ * options values.
+ *
+ * Returns 0 if successful, otherwise standard error code.
+ */
+int cfg_load_from_env(struct config *config);
+
+/*
+ * Returns the default section.
+ *
+ * WARNING: the default section value is returned directly, DO NOT modify it!!!
+ */
+const char *cfg_get_default_section(struct config *config);
+
+/*
+ * Sets the default section, which will be used to set/get values without explicit section specification.
+ * If this method is not called, then empty string is used as the default section (empty string is used by
+ * inih parser for values which are specified without any section in configuration file).
+ *
+ * Returns 0 if successful, otherwise standard error code.
+ */
+int cfg_set_default_section(struct config *config, const char *section_name);
+
+/*
+ * Set the value of the specified configuration option in the default section.
+ *
+ * Returns 0 if successful, otherwise standard error code.
+ */
+int cfg_set_value(struct config *config, const char *option_name, const char *option_value);
+
+/*
+ * Set the value of the specified configuration option in the specified section.
+ *
+ * Returns 0 if successful, otherwise standard error code.
+ */
+int cfg_s_set_value(
+                struct config *config,
+                const char *section_name,
+                const char *option_name,
+                const char *option_value);
+
+/*
+ * Get value of the specified configuration option in the default section.
+ *
+ * Returns the value of the specified option or NULL if option doesn't exist or it doesn't have a value.
+ */
+const char *cfg_get_value(struct config *config, const char *option_name);
+
+/*
+ * Get value of the specified configuration option in the specified section.
+ *
+ * Returns the value of the specified option or NULL if option doesn't exist or it doesn't have a value.
+ */
+const char *cfg_s_get_value(struct config *config, const char *section, const char *option_name);
+
+/*
+ * Get value of the specific configuration option in the default section and convert it to bool type.
+ *
+ * Returns bool value after successful conversion from string or false, if there was an error during
+ * conversion or if the option doesn't exist or have a NULL value.
+ */
+bool cfg_get_bool_value(struct config *config, const char *option_name);
+
+/*
+ * Get value of the specific configuration option in the specified section and convert it to bool type.
+ *
+ * Returns bool value after successful conversion from string or false, if there was an error during
+ * conversion or if the option doesn't exist or have a NULL value.
+ */
+bool cfg_s_get_bool_value(struct config *config, const char *section, const char *option_name);
+
+/*
+ * Iterate over configuration and for each item execute the iter function.
+ * For example using following iterator method would print the whole configuration:
+ *
+ *     bool config_option_iterator(const void *item, void *udata) {
+ *         const struct config_option *option = item;
+ *         printf("%s = %s\n", option->name, option->value);
+ *         return true;
+ *     }
+ *
+ * WARNING: configuration items are accessed directly, DO NOT modify them during iteration!!!
+ */
+void cfg_iterate(struct config *config, bool (*iter)(const void *item, void *udata), void *udata);