Fix confusing error message when dynamic security config file was a d…

…irectory.

Closes #2520. Thanks to sezanzeb

ChangeLog.txt

@@ -20,6 +20,8 @@ Broker:
  taken over. Closes #2607.
 - Fix confusing "out of memory" error when a client is kicked in the dynamic
  security plugin. Closes #2525.
+- Fix confusing error message when dynamic security config file was a
+ directory. Closes #2520.
 
 Client library:
 - Fix threads library detection on Windows under cmake. Bumps the minimum

plugins/dynamic-security/plugin.c

@@ -361,15 +361,21 @@ static int dynsec__config_load(void)
  fptr = fopen(config_file, "rb");
  if(fptr == NULL){
  mosquitto_log_printf(MOSQ_LOG_ERR, "Error loading Dynamic security plugin config: File is not readable - check permissions.\n");
- return 1;
+ return MOSQ_ERR_ERRNO;
+ }
+#ifndef WIN32
+ if(errno == ENOTDIR || errno == EISDIR){
+ mosquitto_log_printf(MOSQ_LOG_ERR, "Error loading Dynamic security plugin config: Config is not a file.\n");
+ return MOSQ_ERR_ERRNO;
  }
+#endif
 
  fseek(fptr, 0, SEEK_END);
  flen_l = ftell(fptr);
  if(flen_l < 0){
  mosquitto_log_printf(MOSQ_LOG_ERR, "Error loading Dynamic security plugin config: %s\n", strerror(errno));
  fclose(fptr);
- return 1;
+ return MOSQ_ERR_ERRNO;
  }else if(flen_l == 0){
  fclose(fptr);
  return 0;
@@ -380,21 +386,21 @@ static int dynsec__config_load(void)
  if(json_str == NULL){
  mosquitto_log_printf(MOSQ_LOG_ERR, "Error: Out of memory.");
  fclose(fptr);
- return 1;
+ return MOSQ_ERR_NOMEM;
  }
  if(fread(json_str, 1, flen, fptr) != flen){
  mosquitto_log_printf(MOSQ_LOG_WARNING, "Error loading Dynamic security plugin config: Unable to read file contents.\n");
  mosquitto_free(json_str);
  fclose(fptr);
- return 1;
+ return MOSQ_ERR_ERRNO;
  }
  fclose(fptr);
 
  tree = cJSON_Parse(json_str);
  mosquitto_free(json_str);
  if(tree == NULL){
  mosquitto_log_printf(MOSQ_LOG_ERR, "Error loading Dynamic security plugin config: File is not valid JSON.\n");
- return 1;
+ return MOSQ_ERR_INVAL;
  }
 
  if(dynsec__general_config_load(tree)
@@ -404,7 +410,7 @@ static int dynsec__config_load(void)
  ){
 
  cJSON_Delete(tree);
- return 1;
+ return MOSQ_ERR_NOMEM;
  }
 
  cJSON_Delete(tree);