Add a sysctl/tunable, "kern.always_console_output", that lets you set

output to permanently (not ephemerally) go to the console.  It is also
sent to any other console specified by TIOCCONS as normal.

While I'm here, document the kern.log_console_output sysctl.

1 files changed, 12 insertions, 3 deletions

diff --git a/sys/kern/subr_prf.c b/sys/kern/subr_prf.c
index 64e4eb1..9f4bedd 100644
--- a/sys/kern/subr_prf.c
+++ b/sys/kern/subr_prf.c
@@ -97,7 +97,12 @@ int msgbuftrigger;
 static int      log_console_output = 1;
 TUNABLE_INT("kern.log_console_output", &log_console_output);
 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
-    &log_console_output, 0, "");
+    &log_console_output, 0, "Duplicate console output to the syslog.");
+
+static int	always_console_output = 0;
+TUNABLE_INT("kern.always_console_output", &always_console_output);
+SYSCTL_INT(_kern, OID_AUTO, always_console_output, CTLFLAG_RW,
+    &always_console_output, 0, "Always output to console despite TIOCCONS.");
 
 /*
  * Warn that a system table is full.
@@ -345,8 +350,12 @@ putchar(int c, void *arg)
 	} else {
 		if ((flags & TOTTY) && tp != NULL)
 			tputchar(c, tp);
-		if ((flags & TOCONS) && constty != NULL)
-			msgbuf_addchar(&consmsgbuf, c);
+		if (flags & TOCONS) {
+			if (constty != NULL)
+				msgbuf_addchar(&consmsgbuf, c);
+			if (always_console_output && c != '\0')
+				cnputc(c);
+		}
 	}
 	if ((flags & TOLOG))
 		msglogchar(c, ap->pri);