console: forbid ctrlc during startup

When global.autoboot_abort_key is set to ctrl-c then the user is
expected to press ctrl-c to get to the prompt. The user might press
ctrl-c before the init script runs the "timeout" command. In this
case the init script is aborted at arbitrary places which leads to
inconsistent results depending on the place it is aborted.

This patch introduces the global.console.ctrlc_allowed variable.
When this variable is set to false ctrl-c is ignored entirely.
The variable is set to false by default and changed to true in
the init script.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 24 insertions, 0 deletions

diff --git a/common/console.c b/common/console.c
index b6685ecf6a..406722a1da 100644
--- a/common/console.c
+++ b/common/console.c
@@ -575,6 +575,7 @@ void console_flush(void)
 EXPORT_SYMBOL(console_flush);
 
 static int ctrlc_abort;
+static int ctrlc_allowed;
 
 void ctrlc_handled(void)
 {
@@ -586,6 +587,9 @@ int ctrlc(void)
 {
 	int ret = 0;
 
+	if (!ctrlc_allowed)
+		return 0;
+
 	if (ctrlc_abort)
 		return 1;
 
@@ -605,5 +609,25 @@ int ctrlc(void)
 }
 EXPORT_SYMBOL(ctrlc);
 
+static int console_ctrlc_init(void)
+{
+	globalvar_add_simple_bool("console.ctrlc_allowed", &ctrlc_allowed);
+	return 0;
+}
+device_initcall(console_ctrlc_init);
+
+void console_ctrlc_allow(void)
+{
+	ctrlc_allowed = 1;
+}
+
+void console_ctrlc_forbid(void)
+{
+	ctrlc_allowed = 0;
+}
+
+BAREBOX_MAGICVAR_NAMED(global_console_ctrlc_allowed, global.console.ctrlc_allowed,
+		"If true, scripts can be aborted with ctrl-c");
+
 BAREBOX_MAGICVAR_NAMED(global_linux_bootargs_console, global.linux.bootargs.console,
 		"console= argument for Linux from the stdout-path property in /chosen node");