hush: Print error messages on shift -1

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

4 files changed, 33 insertions, 2 deletions

diff --git a/shell/ash_test/ash-misc/shift1.tests b/shell/ash_test/ash-misc/shift1.tests
index 0992d9b1b..2774b35ea 100755
--- a/shell/ash_test/ash-misc/shift1.tests
+++ b/shell/ash_test/ash-misc/shift1.tests
@@ -1,5 +1,5 @@
 $THIS_SH -c 'shift;    echo "$@"' 0 1 2 3 4
-#We do abort on -1, but then we abort. bash executes echo.
+# We do complain on -1, but then we abort. bash executes echo.
 $THIS_SH -c 'shift -1; echo "$@"' 0 1 2 3 4
 $THIS_SH -c 'shift  0; echo "$@"' 0 1 2 3 4
 $THIS_SH -c 'shift  1; echo "$@"' 0 1 2 3 4
diff --git a/shell/hush.c b/shell/hush.c
index f6b50dec6..0ade2ccca 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -9377,7 +9377,18 @@ static int FAST_FUNC builtin_shift(char **argv)
 	int n = 1;
 	argv = skip_dash_dash(argv);
 	if (argv[0]) {
-		n = atoi(argv[0]);
+		n = bb_strtou(argv[0], NULL, 10);
+		if (errno || n < 0) {
+			/* shared string with ash.c */
+			bb_error_msg("Illegal number: %s", argv[0]);
+			/*
+			 * ash aborts in this case.
+			 * bash prints error message and set $? to 1.
+			 * Interestingly, for "shift 99999" bash does not
+			 * print error message, but does set $? to 1
+			 * (and does no shifting at all).
+			 */
+		}
 	}
 	if (n >= 0 && n < G.global_argc) {
 		if (G_global_args_malloced) {
diff --git a/shell/hush_test/hush-misc/shift1.right b/shell/hush_test/hush-misc/shift1.right
new file mode 100644
index 000000000..e3ab61392
--- /dev/null
+++ b/shell/hush_test/hush-misc/shift1.right
@@ -0,0 +1,10 @@
+2 3 4
+hush: Illegal number: -1
+1 2 3 4
+1 2 3 4
+2 3 4
+3 4
+4
+
+1 2 3 4
+1 2 3 4
diff --git a/shell/hush_test/hush-misc/shift1.tests b/shell/hush_test/hush-misc/shift1.tests
new file mode 100755
index 000000000..f2a264751
--- /dev/null
+++ b/shell/hush_test/hush-misc/shift1.tests
@@ -0,0 +1,10 @@
+$THIS_SH -c 'shift;    echo "$@"' 0 1 2 3 4
+#We complain on -1 and continue.
+$THIS_SH -c 'shift -1; echo "$@"' 0 1 2 3 4
+$THIS_SH -c 'shift  0; echo "$@"' 0 1 2 3 4
+$THIS_SH -c 'shift  1; echo "$@"' 0 1 2 3 4
+$THIS_SH -c 'shift  2; echo "$@"' 0 1 2 3 4
+$THIS_SH -c 'shift  3; echo "$@"' 0 1 2 3 4
+$THIS_SH -c 'shift  4; echo "$@"' 0 1 2 3 4
+$THIS_SH -c 'shift  5; echo "$@"' 0 1 2 3 4
+$THIS_SH -c 'shift  6; echo "$@"' 0 1 2 3 4