Fixed passed ot open() for O_CREAT

In nuttx the mode parameter to open is not required but in Linux,
and per the POSIX spec, mode is required if the O_CREAT flag is
passed.

The mode flags are different for NuttX and Linux so a new set of
PX4 defines was added:

PX4_O_MODE_777 - read, write, execute for user, group and other
PX4_O_MODE_666 - read, and write for user, group and other
PX4_O_MODE_600 - read, and write for user

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/modules/dataman/dataman.c

@@ -672,12 +672,7 @@ task_main(int argc, char *argv[])
 	}
 
 	/* Open or create the data manager file */
-	g_task_fd = open(k_data_manager_device_path, O_RDWR | O_CREAT | O_BINARY
-#ifdef __PX4_LINUX
-			// Open with read/write permission for user
-			, S_IRUSR | S_IWUSR
-#endif
-			);
+	g_task_fd = open(k_data_manager_device_path, O_RDWR | O_CREAT | O_BINARY, PX4_O_MODE_666);
 
 	if (g_task_fd < 0) {
 		warnx("Could not open data manager file %s", k_data_manager_device_path);

src/modules/mavlink/mavlink_ftp.cpp

@@ -455,7 +455,8 @@ MavlinkFTP::_workOpen(PayloadHeader* payload, int oflag)
 	}
 	fileSize = st.st_size;
 
-	int fd = ::open(filename, oflag);
+	// Set mode to 666 incase oflag has O_CREAT
+	int fd = ::open(filename, oflag, PX4_O_MODE_666);
 	if (fd < 0) {
 		return kErrFailErrno;
 	}

src/modules/sdlog2/sdlog2.c

@@ -505,7 +505,7 @@ int open_log_file()
 		}
 	}
 
-	int fd = open(log_file_path, O_CREAT | O_WRONLY | O_DSYNC, 0x0777);
+	int fd = open(log_file_path, O_CREAT | O_WRONLY | O_DSYNC, PX4_O_MODE_666);
 
 	if (fd < 0) {
 		mavlink_and_console_log_critical(mavlink_fd, "[sdlog2] failed opening: %s", log_file_name);

src/modules/systemlib/param/param.c

@@ -728,7 +728,7 @@ param_save_default(void)
 	const char *filename = param_get_default_file();
 
 	/* write parameters to temp file */
-	fd = PARAM_OPEN(filename, O_WRONLY | O_CREAT, 0x777);
+	fd = PARAM_OPEN(filename, O_WRONLY | O_CREAT, PX4_O_MODE_666);
 
 	if (fd < 0) {
 		warn("failed to open param file: %s", filename);