From 56ee5d3aac2d73dbe1e699000cb83eea18278e68 Mon Sep 17 00:00:00 2001
From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Date: Tue, 17 Sep 2013 09:50:04 +0200
Subject: [PATCH] process_escape_sequence: add support to \$?

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 common/hush.c                 |  6 ++++++
 common/parser.c               |  9 +++++++++
 include/shell.h               | 12 ++++++++++++
 lib/process_escape_sequence.c |  7 +++++++
 4 files changed, 34 insertions(+)
 create mode 100644 include/shell.h

diff --git a/common/hush.c b/common/hush.c
index a3235ba19..bf1d9e6fd 100644
--- a/common/hush.c
+++ b/common/hush.c
@@ -123,6 +123,7 @@
 #include <linux/list.h>
 #include <binfmt.h>
 #include <init.h>
+#include <shell.h>
 
 /*cmd_boot.c*/
 extern int do_bootd(int flag, int argc, char *argv[]);      /* do_bootd */
@@ -226,6 +227,11 @@ static char console_buffer[CONFIG_CBSIZE];		/* console I/O buffer	*/
  * the first three support $?, $#, and $1 */
 static unsigned int last_return_code;
 
+int shell_get_last_return_code(void)
+{
+	return last_return_code;
+}
+
 /* "globals" within this file */
 static uchar *ifs;
 static char map[256];
diff --git a/common/parser.c b/common/parser.c
index 4d993dfd3..d390fb6af 100644
--- a/common/parser.c
+++ b/common/parser.c
@@ -1,6 +1,15 @@
 #include <common.h>
 #include <command.h>
 #include <environment.h>
+#include <shell.h>
+
+/*
+ * not yet supported
+ */
+int shell_get_last_return_code(void)
+{
+	return 0;
+}
 
 static int parse_line (char *line, char *argv[])
 {
diff --git a/include/shell.h b/include/shell.h
new file mode 100644
index 000000000..b98cac3dc
--- /dev/null
+++ b/include/shell.h
@@ -0,0 +1,12 @@
+/*
+ * (C) Copyright 2013 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * Under GPLv2 only
+ */
+
+#ifndef __SHELL_H__
+#define __SHELL_H__
+
+int shell_get_last_return_code(void);
+
+#endif /* __SHELL_H__ */
diff --git a/lib/process_escape_sequence.c b/lib/process_escape_sequence.c
index be7779278..47a7e5cd9 100644
--- a/lib/process_escape_sequence.c
+++ b/lib/process_escape_sequence.c
@@ -19,6 +19,7 @@
 #include <common.h>
 #include <fs.h>
 #include <libbb.h>
+#include <shell.h>
 
 int process_escape_sequence(const char *source, char *dest, int destlen)
 {
@@ -59,6 +60,12 @@ int process_escape_sequence(const char *source, char *dest, int destlen)
 			case 'w':
 				i += snprintf(dest + i, destlen - i, "%s", getcwd());
 				break;
+			case '$':
+				if (*(source + 2) == '?') {
+					i += snprintf(dest + i, destlen - i, "%d", shell_get_last_return_code());
+					source++;
+					break;
+				}
 			default:
 				dest[i++] = '\\';
 				dest[i++] = *(source + 1);