--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -88,6 +88,7 @@ static char *event_source = NULL;
 static char *register_servicename = "PostgreSQL";		/* FIXME: + version ID? */
 static char *register_username = NULL;
 static char *register_password = NULL;
+static char *username = "";
 static char *argv0 = NULL;
 static bool allow_core_files = false;
 static time_t start_time;
@@ -1930,6 +1931,9 @@ do_help(void)
 #endif
 	printf(_("  -s, --silent           only print errors, no informational messages\n"));
 	printf(_("  -t, --timeout=SECS     seconds to wait when using -w option\n"));
+#if !defined(WIN32) && !defined(__CYGWIN__)
+	printf(_("  -U, --username=NAME    user name of account PostgreSQL server is running as\n"));
+#endif
 	printf(_("  -V, --version          output version information, then exit\n"));
 	printf(_("  -w                     wait until operation completes\n"));
 	printf(_("  -W                     do not wait until operation completes\n"));
@@ -2126,6 +2130,7 @@ main(int argc, char **argv)
 		{"pgdata", required_argument, NULL, 'D'},
 		{"silent", no_argument, NULL, 's'},
 		{"timeout", required_argument, NULL, 't'},
+		{"username", required_argument, NULL, 'U'},
 		{"core-files", no_argument, NULL, 'c'},
 		{NULL, 0, NULL, 0}
 	};
@@ -2166,20 +2171,6 @@ main(int argc, char **argv)
 		}
 	}
 
-	/*
-	 * Disallow running as root, to forestall any possible security holes.
-	 */
-#ifndef WIN32
-	if (geteuid() == 0)
-	{
-		write_stderr(_("%s: cannot be run as root\n"
-					   "Please log in (using, e.g., \"su\") as the "
-					   "(unprivileged) user that will\n"
-					   "own the server process.\n"),
-					 progname);
-		exit(1);
-	}
-#endif
 
 	env_wait = getenv("PGCTLTIMEOUT");
 	if (env_wait != NULL)
@@ -2265,11 +2256,15 @@ main(int argc, char **argv)
 					wait_seconds_arg = true;
 					break;
 				case 'U':
+#if defined(WIN32) || defined(__CYGWIN__)
 					if (strchr(optarg, '\\'))
 						register_username = pg_strdup(optarg);
 					else
 						/* Prepend .\ for local accounts */
 						register_username = psprintf(".\\%s", optarg);
+#else
+					username = pg_strdup(optarg);
+#endif
 					break;
 				case 'w':
 					do_wait = true;
@@ -2351,6 +2346,41 @@ main(int argc, char **argv)
 		exit(1);
 	}
 
+	/*
+	 * Disallow running as root, to forestall any possible security holes.
+	 */
+#if !defined(WIN32) && !defined(__CYGWIN__)
+	if (geteuid() == 0)
+	{
+		struct passwd *p;
+		if (!username || !strlen(username)) {
+			fprintf(stderr,
+					_("%s: when run as root, username needs to be provided\n"),
+					progname);
+			exit(1);
+		}
+		p = getpwnam(username);
+		if (!p) {
+			fprintf(stderr,
+					_("%s: invalid username: %s\n"),
+					progname, username);
+			exit(1);
+		}
+		if (!p->pw_uid) {
+			fprintf(stderr,
+					_("%s: user needs to be non-root\n"),
+					progname);
+			exit(1);
+		}
+		if (setgid(p->pw_gid) || setuid(p->pw_uid)) {
+			fprintf(stderr,
+					_("%s: failed to set user id %d: %d (%s)\n"),
+					progname, p->pw_uid, errno, strerror(errno));
+			exit(1);
+		}
+	}
+#endif
+
 	/* Note we put any -D switch into the env var above */
 	pg_config = getenv("PGDATA");
 	if (pg_config)