hush: fix a=abc; c=c; echo ${a%${c}}

function                                             old     new   delta
expand_vars_to_list                                 2229    2302     +73
add_till_closing_paren                               286     313     +27
handle_dollar                                        623     574     -49
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 100/-49)            Total: 51 bytes

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

4 files changed, 75 insertions, 60 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 6d91a534a..a3df5edcd 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2638,11 +2638,21 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
                                                 if (exp_op == *exp_word)        /* ## or %% */
                                                         exp_word++;
                                                 val = to_be_freed = xstrdup(val);
-                                                loc = scan(to_be_freed, exp_word, match_at_left);
-                                                if (match_at_left) /* # or ## */
-                                                        val = loc;
-                                                else if (loc) /* % or %% and match was found */
-                                                        *loc = '\0';
+                                                {
+                                                        char *exp_exp_word = expand_pseudo_dquoted(exp_word);
+                                                        if (exp_exp_word)
+                                                                exp_word = exp_exp_word;
+                                                        loc = scan(to_be_freed, exp_word, match_at_left);
+                                                        //bb_error_msg("op:%c str:'%s' pat:'%s' res:'%s'",
+                                                        //              exp_op, to_be_freed, exp_word, loc);
+                                                        free(exp_exp_word);
+                                                }
+                                                if (loc) { /* match was found */
+                                                        if (match_at_left) /* # or ## */
+                                                                val = loc;
+                                                        else /* % or %% */
+                                                                *loc = '\0';
+                                                }
                                         }
                                 } else if (!strchr("%#:-=+?"+3, exp_op)) {
 #if ENABLE_HUSH_BASH_COMPAT
@@ -5876,20 +5886,28 @@ static void add_till_backquote(o_string *dest, struct in_str *input)
  * echo $(echo '(TEST)' BEST)           (TEST) BEST
  * echo $(echo 'TEST)' BEST)            TEST) BEST
  * echo $(echo \(\(TEST\) BEST)         ((TEST) BEST
+ *
+ * BUG: enter: echo $(( `printf '(\x28 1'` + `echo 2))` ))
+ * on the command line, press Enter. You get > prompt which is impossible
+ * to exit with ^C.
  */
-static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl)
+#define DOUBLE_CLOSE_CHAR_FLAG 0x80
+static void add_till_closing_paren(o_string *dest, struct in_str *input, char end_ch)
 {
         int count = 0;
+        char dbl = end_ch & DOUBLE_CLOSE_CHAR_FLAG;
+        end_ch &= (DOUBLE_CLOSE_CHAR_FLAG-1);
         while (1) {
                 int ch = i_getch(input);
                 if (ch == EOF) {
                         syntax_error_unterm_ch(')');
                         /*xfunc_die(); - redundant */
                 }
-                if (ch == '(')
+                if (ch == '(' || ch == '{')
                         count++;
-                if (ch == ')') {
-                        if (--count < 0) {
+                if (ch == ')' || ch == '}') {
+                        count--;
+                        if (count < 0 && ch == end_ch) {
                                 if (!dbl)
                                         break;
                                 if (i_peek(input) == ')') {
@@ -5969,62 +5987,52 @@ static int handle_dollar(o_string *as_string,
         case '@': /* args */
                 goto make_one_char_var;
         case '{': {
-                bool first_char, all_digits;
-                bool in_expansion_param;
+                o_addchr(dest, SPECIAL_VAR_SYMBOL);
 
-                ch = i_getch(input);
+                ch = i_getch(input); /* eat '{' */
                 nommu_addchr(as_string, ch);
-                o_addchr(dest, SPECIAL_VAR_SYMBOL);
 
-// TODO: need to handle "a=ab}; echo ${a%\}}"
-// and "a=abc; c=c; echo ${a%${c}}"
-                in_expansion_param = false;
-                first_char = true;
-                all_digits = false;
+                ch = i_getch(input); /* first char after '{' */
+                nommu_addchr(as_string, ch);
+                /* It should be ${?}, or ${#var},
+                 * or even ${?+subst} - operator acting on a special variable,
+                 * or the beginning of variable name.
+                 */
+                if (!strchr("$!?#*@_", ch) && !isalnum(ch)) { /* not one of those */
+ bad_dollar_syntax:
+                        syntax_error_unterm_str("${name}");
+                        debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
+                        return 1;
+                }
+                ch |= quote_mask;
+
+                /* It's possible to just call add_till_closing_paren() at this point.
+                 * However, this regresses some of our testsuite cases
+                 * which check invalid constructs like ${%}.
+                 * Oh well... let's check that the var name part is fine... */
+
                 while (1) {
+                        o_addchr(dest, ch);
+                        debug_printf_parse(": '%c'\n", ch);
+
                         ch = i_getch(input);
                         nommu_addchr(as_string, ch);
-                        if (ch == '}') {
+                        if (ch == '}')
                                 break;
-                        }
 
-                        if (first_char) {
-                                if (ch == '#') {
-                                        /* ${#var}: length of var contents */
-                                        goto char_ok;
-                                }
-                                if (isdigit(ch)) {
-                                        all_digits = true;
-                                        goto char_ok;
-                                }
-                                /* They're being verbose and doing ${?} */
-                                if (i_peek(input) == '}' && strchr("$!?#*@_", ch))
-                                        goto char_ok;
-                        }
-
-                        if (!in_expansion_param
-                         && (  (all_digits && !isdigit(ch)) /* met non-digit: 123w */
-                            || (!all_digits && !isalnum(ch) && ch != '_') /* met non-name char: abc% */
-                            )
-                        ) {
+                        if (!isalnum(ch) && ch != '_') {
                                 /* handle parameter expansions
                                  * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
                                  */
-                                if (first_char /* bad (empty var name): "${%..." */
-                                 || !strchr("%#:-=+?", ch) /* bad: "${var<bad_char>..." */
-                                ) {
-                                        syntax_error_unterm_str("${name}");
-                                        debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
-                                        return 1;
-                                }
-                                in_expansion_param = true;
+                                if (!strchr("%#:-=+?", ch)) /* ${var<bad_char>... */
+                                        goto bad_dollar_syntax;
+                                /* Eat everything until closing '}' */
+                                o_addchr(dest, ch);
+//TODO: add nommu_addchr hack here
+                                add_till_closing_paren(dest, input, '}');
+                                break;
                         }
- char_ok:
-                        debug_printf_parse(": '%c'\n", ch);
-                        o_addchr(dest, ch | quote_mask);
-                        quote_mask = 0;
-                        first_char = false;
-                } /* while (1) */
+                }
                 o_addchr(dest, SPECIAL_VAR_SYMBOL);
                 break;
         }
@@ -6044,7 +6052,7 @@ static int handle_dollar(o_string *as_string,
 #  if !BB_MMU
                         pos = dest->length;
 #  endif
-                        add_till_closing_paren(dest, input, true);
+                        add_till_closing_paren(dest, input, ')' | DOUBLE_CLOSE_CHAR_FLAG);
 #  if !BB_MMU
                         if (as_string) {
                                 o_addstr(as_string, dest->data + pos);
@@ -6062,7 +6070,7 @@ static int handle_dollar(o_string *as_string,
 #  if !BB_MMU
                 pos = dest->length;
 #  endif
-                add_till_closing_paren(dest, input, false);
+                add_till_closing_paren(dest, input, ')');
 #  if !BB_MMU
                 if (as_string) {
                         o_addstr(as_string, dest->data + pos);
diff --git a/shell/hush_test/hush-vars/var3.right b/shell/hush_test/hush-vars/var3.right
index 5e28d2fab..40e67fdf5 100644
--- a/shell/hush_test/hush-vars/var3.right
+++ b/shell/hush_test/hush-vars/var3.right
@@ -1,2 +1,2 @@
-hush: syntax error: unterminated ${name}
+hush: invalid number '1q'
 hush: syntax error: unterminated ${name}
diff --git a/shell/hush_test/hush-vars/var_posix1.right b/shell/hush_test/hush-vars/var_posix1.right
index e6cba2758..813437e2f 100644
--- a/shell/hush_test/hush-vars/var_posix1.right
+++ b/shell/hush_test/hush-vars/var_posix1.right
@@ -23,6 +23,7 @@ babcdcd
 ababcdcd
 Empty:
 ababcdcd}_tail
+ababcdcd_tail
 ababcd
 ababcd
 ababcd
@@ -32,5 +33,8 @@ ababcdc
 ababcdcd
 Empty:
 ababcdcd}_tail
+ababcdcd_tail
 ababcdcd
-end
+ab
+ab
+End
diff --git a/shell/hush_test/hush-vars/var_posix1.tests b/shell/hush_test/hush-vars/var_posix1.tests
index c1f64094d..e48fd98c7 100755
--- a/shell/hush_test/hush-vars/var_posix1.tests
+++ b/shell/hush_test/hush-vars/var_posix1.tests
@@ -31,7 +31,7 @@ echo ${var##?}
 echo ${var#*}
 echo Empty:${var##*}
 echo ${var#}}_tail
-# UNFIXED BUG: echo ${var#\}}_tail
+echo ${var#\}}_tail
 
 echo ${var%cd}
 echo ${var%%cd}
@@ -42,7 +42,10 @@ echo ${var%%?}
 echo ${var%*}
 echo Empty:${var%%*}
 echo ${var#}}_tail
-# UNFIXED BUG: echo ${var#\}}_tail
+echo ${var#\}}_tail
 echo ${var%\\*}
 
-echo end
+a=ab}; echo ${a%\}};
+a=abc; c=c; echo ${a%${c}}
+
+echo End