conf_merge.c

void create_new_cofg(char *usr_conf, char *def_conf)
{
	int done = 0;
	FILE *usr_fp = NULL, *def_fp = NULL, *temp_fp = NULL;
	char buf[CONFIG_BUFFER] = {0};

	//get currect sep by config name
	char *fname = get_fname(usr_conf);
	char *sep = find_file_sep(fname);

	//save current setting in binary tree for searching
	void *conf_root = NULL;
	create_binary_tree(usr_conf, &conf_root);

	//prepare a temp file
	char temp_conf[NAME_MAX] = {0};
	snprintf(temp_conf, sizeof(temp_conf), "%s/merge.temp", dirname(strdupa(usr_conf)));
	fprintf(stderr, "temp_conf: %s\n", temp_conf);
	temp_fp = fopen(temp_conf, "w+");
	if(temp_fp == NULL) {
		fprintf(stderr, "Error: fail to create temp file: %s\n", temp_conf);
		goto error;
	}

	//prepare def_conf
	def_fp = fopen(def_conf, "r");
	if(def_fp == NULL) {
		fprintf(stderr, "Error: fail to open default config: %s\n", def_conf);
		goto error;
	}

	//prepare usr_conf
	usr_fp = fopen(usr_conf, "r");
	if(usr_fp == NULL) {
		fprintf(stderr, "Error: fail to open user config: %s\n", usr_conf);
		goto error;
	}

	//copy def_conf's version to temp
	while(fgets(buf, sizeof(buf), def_fp) != NULL) {
		if(strncmp(buf, VERSION_TAG, strlen(VERSION_TAG)) == 0) {
			del_str_brackets(buf);
			rm_blank(buf);
			fprintf(temp_fp, "%s\n", buf);
			break;
		}
	}

	//copy usr_conf to temp exclude version
	while(fgets(buf, sizeof(buf), usr_fp) != NULL) {
		if(strncmp(buf, VERSION_TAG, strlen(VERSION_TAG)) == 0) {
			continue; //skip version line
		}
		fprintf(temp_fp, "%s", buf);
	}

	//copy def_conf to temp exclude existing in binary tree
	while(fgets(buf, sizeof(buf), def_fp) != NULL) {
		if(strncmp(buf, VERSION_TAG, strlen(VERSION_TAG)) == 0) {
			continue; //skip version line
		}

		char pbuf[CONFIG_BUFFER] = {0};
		strcpy(pbuf, buf);
		del_str_comment_LF(pbuf);
		if(strlen(pbuf) < 1) {
			continue;
		}

		//prepare tree key
		CONF_NODE *newNode = read_key_value(pbuf, sep);
		if(newNode == NULL) {
			continue;
		}
		if(tfind(newNode, &conf_root, func_name_compare) == NULL) {
			//buf in not in tree, copy it into temp
			fprintf(temp_fp, "%s", buf);
		}
		free_conf_node(newNode);
	}
	done = 1;

error:
	if(usr_fp != NULL) {
		fclose(usr_fp);
	}
	if(def_fp != NULL) {
		fclose(def_fp);
	}
	if(temp_fp != NULL) {
		int temp_fd = fileno(temp_fp);
		if(temp_fd != -1) {
			fsync(temp_fd); //synchronize to storage device
		}
		fclose(temp_fp);
	}
	if(conf_root != NULL) {
		twalk(conf_root, free_tree);
	}

	if(done) {
		rename(temp_conf, usr_conf);
	}
}