basic/terminal-util: introduce SYSTEMD_COLORS environment variable

... to determine if color output should be enabled. If the variable is not set,
fall back to using on_tty(). Also, rewrite existing code to use
colors_enabled() where appropriate.

1 files changed, 13 insertions, 0 deletions

diff --git a/src/basic/terminal-util.c b/src/basic/terminal-util.c
index 7c9de72bb7..fedfc8a5df 100644
--- a/src/basic/terminal-util.c
+++ b/src/basic/terminal-util.c
@@ -1135,3 +1135,16 @@ int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
 
         return receive_one_fd(pair[0], 0);
 }
+
+bool colors_enabled(void) {
+        const char *colors;
+
+        colors = getenv("SYSTEMD_COLORS");
+        if (!colors) {
+                if (streq_ptr(getenv("TERM"), "dumb"))
+                        return false;
+                return on_tty();
+        }
+
+        return parse_boolean(colors) != 0;
+}