Fixed handling of getenv results

src/tests/cli.cpp

@@ -838,7 +838,13 @@ TEST_F(rnp_tests, test_cli_dump)
 
 TEST_F(rnp_tests, test_cli_logname)
 {
+// !!!!!
+// getenv function is not required to be thread-safe.
+// Another call to getenv, as well as a call to the POSIX functions setenv(), unsetenv(), and putenv()
+// may invalidate the pointer returned by a previous call or modify the string obtained from a previous call.
     char *      logname = getenv("LOGNAME");
+    std::string safe_logname(logname ? logname : "");
+
     char *      user = getenv("USER");
     std::string testname(user ? user : "user");
     testname.append("-test-user");
@@ -851,7 +857,7 @@ TEST_F(rnp_tests, test_cli_logname)
     }
 
     if (logname) {
-        setenv("LOGNAME", logname, 1);
+        setenv("LOGNAME", safe_logname.c_str(), 1);
     } else {
         unsetenv("LOGNAME");
     }