hush: fix negative_arith.tests: glob-protect dash in "$((arith))"

function                                             old     new   delta
expand_vars_to_list                                 1026    1082     +56
parse_dollar                                         810     811      +1
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 57/0)               Total: 57 bytes

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

1 files changed, 19 insertions, 5 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 357a354e2..0a92f5da7 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -3007,7 +3007,10 @@ static void x_mode_flush(void)
 static void o_addqchr(o_string *o, int ch)
 {
         int sz = 1;
-        char *found = strchr("*?[\\" MAYBE_BRACES, ch);
+        /* '-' is included because of this case:
+         * >filename0 >filename1 >filename9; v='-'; echo filename[0"$v"9]
+         */
+        char *found = strchr("*?[-\\" MAYBE_BRACES, ch);
         if (found)
                 sz++;
         o_grow_by(o, sz);
@@ -3024,7 +3027,7 @@ static void o_addQchr(o_string *o, int ch)
 {
         int sz = 1;
         if ((o->o_expflags & EXP_FLAG_ESC_GLOB_CHARS)
-         && strchr("*?[\\" MAYBE_BRACES, ch)
+         && strchr("*?[-\\" MAYBE_BRACES, ch)
         ) {
                 sz++;
                 o->data[o->length] = '\\';
@@ -3041,7 +3044,7 @@ static void o_addqblock(o_string *o, const char *str, int len)
         while (len) {
                 char ch;
                 int sz;
-                int ordinary_cnt = strcspn(str, "*?[\\" MAYBE_BRACES);
+                int ordinary_cnt = strcspn(str, "*?[-\\" MAYBE_BRACES);
                 if (ordinary_cnt > len) /* paranoia */
                         ordinary_cnt = len;
                 o_addblock(o, str, ordinary_cnt);
@@ -3052,7 +3055,7 @@ static void o_addqblock(o_string *o, const char *str, int len)
 
                 ch = *str++;
                 sz = 1;
-                if (ch) { /* it is necessarily one of "*?[\\" MAYBE_BRACES */
+                if (ch) { /* it is necessarily one of "*?[-\\" MAYBE_BRACES */
                         sz++;
                         o->data[o->length] = '\\';
                         o->length++;
@@ -5049,7 +5052,7 @@ static int parse_dollar(o_string *as_string,
                         ch = i_getch(input);
                         nommu_addchr(as_string, ch);
                         o_addchr(dest, SPECIAL_VAR_SYMBOL);
-                        o_addchr(dest, /*quote_mask |*/ '+');
+                        o_addchr(dest, quote_mask | '+');
                         if (!BB_MMU)
                                 pos = dest->length;
                         if (!add_till_closing_bracket(dest, input, ')' | DOUBLE_CLOSE_CHAR_FLAG))
@@ -6851,6 +6854,17 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
                         res = expand_and_evaluate_arith(arg, NULL);
                         debug_printf_subst("ARITH RES '"ARITH_FMT"'\n", res);
                         sprintf(arith_buf, ARITH_FMT, res);
+                        if (res < 0
+                         && first_ch == (char)('+'|0x80)
+                        /* && (output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS) */
+                        ) {
+                                /* Quoted negative ariths, like filename[0"$((-9))"],
+                                 * should not be interpreted as glob ranges.
+                                 * Convert leading '-' to '\-':
+                                 */
+                                o_grow_by(output, 1);
+                                output->data[output->length++] = '\\';
+                        }
                         o_addstr(output, arith_buf);
                         break;
                 }