hush: handle ${var:NUM:} too

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

1 files changed, 8 insertions, 2 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 945077d87..6cf8899b0 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2649,12 +2649,17 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
                                                 beg = bb_strtou(exp_word, &end, 0);
                                         //bb_error_msg("beg:'%s'=%u end:'%s'", exp_word, beg, end);
                                         if (*end == ':') {
-                                                len = bb_strtou(end + 1, &end, 0);
+                                                if (end[1] != '\0') /* not ${var:NUM:} */
+                                                        len = bb_strtou(end + 1, &end, 0);
+                                                else {
+                                                        len = 0;
+                                                        end++;
+                                                }
                                                 //bb_error_msg("len:%u end:'%s'", len, end);
                                         }
                                         if (*end == '\0') {
                                                 //bb_error_msg("from val:'%s'", val);
-                                                if (!val || beg >= strlen(val))
+                                                if (len == 0 || !val || beg >= strlen(val))
                                                         val = "";
                                                 else
                                                         val = dyn_val = xstrndup(val + beg, len);
@@ -2663,6 +2668,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
 #endif
                                         {
                                                 die_if_script("malformed ${%s...}", var);
+                                                val = "";
                                         }
                                 } else { /* one of "-=+?" */
         /* Standard-mandated substitution ops: