config: add the logdir option dynamic reloading support

NOTE: for now this couldn't support the glfs's logging setting, and
the glfs will use the old path.

Signed-off-by: Xiubo Li <xiubli@redhat.com>

libtcmu_config.c

@@ -132,15 +132,17 @@ do { \
 
 static void tcmu_conf_set_options(struct tcmu_config *cfg, bool reloading)
 {
+	int ret;
+
 	/* set log_level option */
 	TCMU_PARSE_CFG_INT(cfg, log_level);
 	if (cfg->log_level) {
 		tcmu_set_log_level(cfg->log_level);
 	}
 
+	/* set log_dir path option */
+	TCMU_PARSE_CFG_STR(cfg, log_dir_path);
 	if (!reloading) {
-		/* set log_dir path option */
-		TCMU_PARSE_CFG_STR(cfg, log_dir_path);
 		/*
 		 * The priority of the logdir setting is:
 		 * 1, --tcmu_log_dir/-l LOG_DIR_PATH
@@ -149,11 +151,19 @@ static void tcmu_conf_set_options(struct tcmu_config *cfg, bool reloading)
 		 * 4, default /var/log/
 		 */
 		if (!tcmu_get_logdir())
-			tcmu_logdir_create(cfg->log_dir_path);
+			tcmu_logdir_create(cfg->log_dir_path, false);
 		else
 			tcmu_warn("The logdir option from the tcmu.conf will be ignored\n");
 	} else {
-		tcmu_warn("The logdir option is not supported by dynamic reloading for now!\n");
+		/*
+		 * Here we asume that users want to change the
+		 * log_dir_path without considering the priority
+		 * mentioned above.
+		 */
+		tcmu_logdir_create(cfg->log_dir_path, true);
+		ret = tcmu_create_file_output(tcmu_get_log_level(), TCMU_LOG_FILENAME, true);
+		if (ret < 0)
+			tcmu_err("create file output error \n");
 	}
 
 	/* add your new config options */

libtcmu_log.c

@@ -59,6 +59,7 @@ struct log_output {
 	char *name;
 	void *data;
 	tcmu_log_destination dest;
+	bool enabled;
 };
 
 static int tcmu_log_level = TCMU_LOG_INFO;
@@ -100,7 +101,7 @@ bool tcmu_logdir_getenv(void)
 	if (!log_path)
 		return true;
 
-	if (!tcmu_logdir_create(log_path))
+	if (!tcmu_logdir_create(log_path, false))
 		return false;
 
 	return true;
@@ -275,12 +276,26 @@ static int append_output(log_output_fn_t output_fn, log_close_fn_t close_fn, voi
 	output.priority = pri;
 	output.dest = dest;
 	output.name = ndup;
+	output.enabled = true;
 
 	darray_append(logbuf->outputs, output);
 
 	return 0;
 }
 
+static void log_output_disable(const tcmu_log_destination dest)
+{
+	struct log_output *output;
+
+	/* This will just find the first one and disable it. */
+	darray_foreach(output, logbuf->outputs) {
+		if (output->dest == dest) {
+			output->enabled = false;
+			break;
+		}
+	}
+}
+
 static int output_to_syslog(int pri, const char *timestamp,
                             const char *str, void *data)
 {
@@ -383,7 +398,7 @@ static int create_stdout_output(int pri)
 	return 0;
 }
 
-static int create_file_output(int pri, const char *filename)
+int tcmu_create_file_output(int pri, const char *filename, bool reloading)
 {
 	char log_file_path[PATH_MAX];
 	int fd, ret;
@@ -408,6 +423,10 @@ static int create_file_output(int pri, const char *filename)
 		return ret;
 	}
 
+	/* Disable the old entries */
+	if (reloading)
+		log_output_disable(TCMU_LOG_TO_FILE);
+
         return 0;
 }
 
@@ -416,15 +435,30 @@ static void log_output(int pri, const char *msg)
 	struct log_output *output;
 	char timestamp[TCMU_TIME_STRING_BUFLEN] = {0, };
 	int ret;
+	int i = 0;
 
 	ret = time_string_now(timestamp);
 	if (ret < 0)
 		return;
 
 	darray_foreach (output, logbuf->outputs) {
-		if (pri <= output->priority) {
-			output->output_fn(pri, timestamp, msg, output->data);
+		if (output->enabled) {
+			if (pri <= output->priority)
+				output->output_fn(pri, timestamp, msg, output->data);
+		} else {
+			/*
+			 * We just close and free the resource here to make
+			 * sure no outputing operation is in process.
+			 */
+			if (output->close_fn != NULL)
+				output->close_fn(output->data);
+			if (output->name != NULL)
+				free(output->name);
+
+			darray_remove(logbuf->outputs, i);
+			continue;
 		}
+		i++;
 	}
 }
 
@@ -533,7 +567,7 @@ char *tcmu_get_logdir(void)
 	return tcmu_log_dir;
 }
 
-static char *tcmu_alloc_and_set_log_dir(const char *log_dir)
+static char *tcmu_alloc_and_set_log_dir(const char *log_dir, bool reloading)
 {
 	/*
 	 * Do nothing here and will use the /var/log/
@@ -542,6 +576,9 @@ static char *tcmu_alloc_and_set_log_dir(const char *log_dir)
 	if (!log_dir)
 		return NULL;
 
+	if (reloading && tcmu_log_dir)
+		free(tcmu_log_dir);
+
 	tcmu_log_dir = strdup(log_dir);
 	if (!tcmu_log_dir)
 		tcmu_err("Failed to copy log dir: %s\n", log_dir);
@@ -601,15 +638,15 @@ static int tcmu_mkdirs(const char *pathname)
 	return tcmu_mkdir(path);
 }
 
-bool tcmu_logdir_create(const char *path)
+bool tcmu_logdir_create(const char *path, bool reloading)
 {
 	if (!tcmu_logdir_check(path))
 		return false;
 
 	if (!tcmu_mkdirs(path))
 		return false;
 
-	return !!tcmu_alloc_and_set_log_dir(path);
+	return !!tcmu_alloc_and_set_log_dir(path, reloading);
 }
 
 int tcmu_make_absolute_logfile(char *path, const char *filename)
@@ -646,7 +683,7 @@ int tcmu_setup_log(void)
 	if (ret < 0)
 		tcmu_err("create stdout output error \n");
 
-	ret = create_file_output(TCMU_LOG_DEBUG, TCMU_LOG_FILENAME);
+	ret = tcmu_create_file_output(TCMU_LOG_DEBUG, TCMU_LOG_FILENAME, false);
 	if (ret < 0)
 		tcmu_err("create file output error \n");
 

libtcmu_log.h

@@ -64,8 +64,9 @@ 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);
+bool tcmu_logdir_create(const char *path, bool reloading);
 int tcmu_make_absolute_logfile(char *path, const char *filename);
+int tcmu_create_file_output(int pri, const char *filename, bool reloading);
 
 
 #define tcmu_dev_err(dev, ...)  {tcmu_err_message(dev, __func__, __LINE__, __VA_ARGS__);}

main.c

@@ -1009,7 +1009,7 @@ int main(int argc, char **argv)
 			}
 			break;
 		case 'l':
-			if (!tcmu_logdir_create(optarg))
+			if (!tcmu_logdir_create(optarg, false))
 				goto free_opt;
 			break;
 		case 'f':