Shell: Handle aborting loops better

It's easy to get stuck in an infinite loop in the hush shell:

while true; do sleep 1; done

The 'sleep' command will check for ctrl-c with the ctrlc() function. This
will abort the sleep command. Hush then checks for ctrl-c again in the
loop. The ctrl-c in the buffer has already been eaten by the sleep
command, so the loop will continue.

With this patch we remember the presence of a ctrl-c character in a
variable instead of checking for a new character each time. The
variable must be resetted explicitly by calling ctrlc_handled() which
will be called by the shell in the outer loop.

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

1 files changed, 23 insertions, 5 deletions

diff --git a/common/console.c b/common/console.c
index 47ccf2e54d..b6685ecf6a 100644
--- a/common/console.c
+++ b/common/console.c
@@ -574,18 +574,36 @@ void console_flush(void)
 }
 EXPORT_SYMBOL(console_flush);
 
-#ifndef ARCH_HAS_CTRLC
+static int ctrlc_abort;
+
+void ctrlc_handled(void)
+{
+	ctrlc_abort = 0;
+}
+
 /* test if ctrl-c was pressed */
-int ctrlc (void)
+int ctrlc(void)
 {
+	int ret = 0;
+
+	if (ctrlc_abort)
+		return 1;
+
 	poller_call();
 
+#ifdef ARCH_HAS_CTRLC
+	ret = arch_ctrlc();
+#else
 	if (tstc() && getchar() == 3)
-		return 1;
-	return 0;
+		ret = 1;
+#endif
+
+	if (ret)
+		ctrlc_abort = 1;
+
+	return ret;
 }
 EXPORT_SYMBOL(ctrlc);
-#endif /* ARCH_HAS_CTRC */
 
 BAREBOX_MAGICVAR_NAMED(global_linux_bootargs_console, global.linux.bootargs.console,
 		"console= argument for Linux from the stdout-path property in /chosen node");