Fix nasa#2529, Adds snprintf check return value in EVS_SendViaPorts

modules/evs/fsw/src/cfe_evs_task.h

@@ -60,7 +60,7 @@
 #define CFE_EVS_MAX_FILTER_COUNT     65535
 #define CFE_EVS_MAX_SQUELCH_COUNT    255
 #define CFE_EVS_PIPE_NAME            "EVS_CMD_PIPE"
-#define CFE_EVS_MAX_PORT_MSG_LENGTH  (CFE_MISSION_EVS_MAX_MESSAGE_LENGTH + OS_MAX_API_NAME + 30)
+#define CFE_EVS_MAX_PORT_MSG_LENGTH  (CFE_MISSION_EVS_MAX_MESSAGE_LENGTH + OS_MAX_API_NAME + 19)
 
 /* Since CFE_EVS_MAX_PORT_MSG_LENGTH is the size of the buffer that is sent to
  * print out (using OS_printf), we need to check to make sure that the buffer
@@ -70,6 +70,13 @@
 #error CFE_EVS_MAX_PORT_MSG_LENGTH cannot be greater than OS_BUFFER_SIZE!
 #endif
 
+/* If CFE_EVS_MAX_PORT_MSG_LENGTH is greater than (CFE_MISSION_EVS_MAX_MESSAGE_LENGTH
+ * + OS_MAX_API_NAME + 19), it could result in the truncation of the new line
+ * character appended downstream. */
+#if CFE_EVS_MAX_PORT_MSG_LENGTH > (CFE_MISSION_EVS_MAX_MESSAGE_LENGTH + OS_MAX_API_NAME + 19)
+#error CFE_EVS_MAX_PORT_MSG_LENGTH exceeds the maximum allowable length to prevent truncation!
+#endif
+
 /************************  Internal Structure Definitions  *****************************/
 
 typedef struct