basic/terminal-util: cache value for colors_enabled

[thirdparty/systemd.git] / src / basic / terminal-util.c

diff --git a/src/basic/terminal-util.c b/src/basic/terminal-util.c
index fedfc8a5dfdb166068c1f89313ff5e9eee01b203..9521b79daa1530580980e4a5b6bdb6f06a13391f 100644 (file)
--- a/src/basic/terminal-util.c
+++ b/src/basic/terminal-util.c
@@ -726,9 +726,7 @@ bool tty_is_vc_resolve(const char *tty) {
 }
 
 const char *default_term_for_tty(const char *tty) {
-        assert(tty);
-
-        return tty_is_vc_resolve(tty) ? "TERM=linux" : "TERM=vt220";
+        return tty && tty_is_vc_resolve(tty) ? "TERM=linux" : "TERM=vt220";
 }
 
 int fd_columns(int fd) {
@@ -1137,14 +1135,19 @@ int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
 }
 
 bool colors_enabled(void) {
-        const char *colors;
+        static int enabled = -1;
 
-        colors = getenv("SYSTEMD_COLORS");
-        if (!colors) {
-                if (streq_ptr(getenv("TERM"), "dumb"))
-                        return false;
-                return on_tty();
+        if (_unlikely_(enabled < 0)) {
+                const char *colors;
+
+                colors = getenv("SYSTEMD_COLORS");
+                if (colors)
+                        enabled = parse_boolean(colors) != 0;
+                else if (streq_ptr(getenv("TERM"), "dumb"))
+                        enabled = false;
+                else
+                        enabled = on_tty();
         }
 
-        return parse_boolean(colors) != 0;
+        return enabled;
 }