logger: logdir path setting via Env variable 'TCMU_LOGDIR'

$ export TCMU_LOGDIR="/var/log/mylogdir/"
$ ./tcmu-runner

or

one can pass 'TCMU_LOGDIR' to list of systemd Env variables and
be able to run via systemd unit

Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>

libtcmu_config.c

@@ -156,8 +156,9 @@ static void tcmu_conf_set_options(struct tcmu_config *cfg, bool reloading)
 		/*
 		 * The priority of the logdir setting is:
 		 * 1, --tcmu_log_dir/-l LOG_DIR_PATH
-		 * 2, tcmu.conf
-		 * 3, default /var/log/
+		 * 2, export TCMU_LOGDIR="/var/log/mychoice/"
+		 * 3, tcmu.conf
+		 * 4, default /var/log/
 		 */
 		if (!tcmu_get_logdir())
 			tcmu_logdir_create(cfg->log_dir_path);

libtcmu_log.c

@@ -88,6 +88,23 @@ unsigned int tcmu_get_log_level(void)
 	return tcmu_log_level;
 }
 
+bool tcmu_logdir_getenv(void)
+{
+	char *log_path;
+
+	if (tcmu_get_logdir())
+		return true;
+
+	log_path = getenv("TCMU_LOGDIR");
+	if (!log_path)
+		return true;
+
+	if (!tcmu_logdir_create(log_path))
+		return false;
+
+	return true;
+}
+
 void tcmu_set_log_level(int level)
 {
 	/* set the default log level to info */

libtcmu_log.h

@@ -63,6 +63,7 @@ void tcmu_dbg_scsi_cmd_message(struct tcmu_device *dev, const char *funcname, in
 
 char *tcmu_get_logdir(void);
 void tcmu_logdir_destroy(void);
+bool tcmu_logdir_getenv(void);
 bool tcmu_logdir_create(const char *path);
 int tcmu_make_absolute_logfile(char *path, const char *filename);
 

main.c

@@ -955,6 +955,9 @@ int main(int argc, char **argv)
 		}
 	}
 
+	if (!tcmu_logdir_getenv())
+		goto free_opt;
+
 	/*
 	 * The order of setting up config and logger is important, because
 	 * the log directory may be configured via the system config file