visibility.h: add #pragma GCC poison getenv setenv putenv

Just to make sure that it will never be used on NuttX. This is not an
architectural limitation, just a memory optimization, since we call
clearenv() on NuttX.

src/include/visibility.h

@@ -39,8 +39,7 @@
  * This file is normally included automatically by the build system.
  */
 
-#ifndef __SYSTEMLIB_VISIBILITY_H
-#define __SYSTEMLIB_VISIBILITY_H
+#pragma once
 
 #ifdef __EXPORT
 #  undef __EXPORT
@@ -59,4 +58,15 @@
 #  define __BEGIN_DECLS
 #  define __END_DECLS
 #endif
-#endif
+
+
+#ifdef __PX4_NUTTX
+/* On NuttX we call clearenv() so we cannot use getenv() and others (see px4_task_spawn_cmd() in px4_nuttx_tasks.c).
+ * We need to include the headers declaring getenv() before the pragma, otherwise it will trigger a poison error.
+ */
+#include <stdlib.h>
+#ifdef __cplusplus
+#include <cstdlib>
+#endif
+#pragma GCC poison getenv setenv putenv
+#endif /* __PX4_NUTTX */

src/modules/logger/logger.cpp

@@ -370,6 +370,7 @@ void Logger::run_trampoline(int argc, char *argv[])
 		PX4_ERR("alloc failed");
 
 	} else {
+#ifndef __PX4_NUTTX
 		//check for replay mode
 		const char *logfile = getenv(px4::replay::ENV_FILENAME);
 
@@ -377,6 +378,8 @@ void Logger::run_trampoline(int argc, char *argv[])
 			logger_ptr->setReplayFile(logfile);
 		}
 
+#endif /* __PX4_NUTTX */
+
 		logger_ptr->run();
 	}
 

src/modules/replay/definitions.hpp

@@ -38,7 +38,7 @@ namespace px4
 namespace replay
 {
 
-static const char *ENV_FILENAME = "replay"; ///< name for getenv()
+static const char __attribute__((unused)) *ENV_FILENAME = "replay"; ///< name for getenv()
 static const char __attribute__((unused)) *ENV_MODE = "replay_mode";  ///< name for getenv()