hush: handle expansions in ${var?expanded_word} constructs

function                                             old     new   delta
expand_vars_to_list                                 2209    2229     +20

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

1 files changed, 27 insertions, 15 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 1937d24e4..6d91a534a 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2403,6 +2403,23 @@ static char *expand_pseudo_dquoted(const char *str)
         return exp_str;
 }
 
+#if ENABLE_SH_MATH_SUPPORT
+static arith_t expand_and_evaluate_arith(const char *arg, int *errcode_p)
+{
+        arith_eval_hooks_t hooks;
+        arith_t res;
+        char *exp_str;
+
+        hooks.lookupvar = get_local_var_value;
+        hooks.setvar = set_local_var_from_halves;
+        hooks.endofname = endofname;
+        exp_str = expand_pseudo_dquoted(arg);
+        res = arith(exp_str ? exp_str : arg, errcode_p, &hooks);
+        free(exp_str);
+        return res;
+}
+#endif
+
 /* Expand all variable references in given string, adding words to list[]
  * at n, n+1,... positions. Return updated n (so that list[n] is next one
  * to be filled). This routine is extremely tricky: has to deal with
@@ -2427,7 +2444,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
         while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
                 char first_ch;
                 int i;
-                char *dyn_val = NULL;
+                char *to_be_freed = NULL;
                 const char *val = NULL;
 #if ENABLE_HUSH_TICK
                 o_string subst_result = NULL_O_STRING;
@@ -2528,21 +2545,13 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
 #endif
 #if ENABLE_SH_MATH_SUPPORT
                 case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
-                        arith_eval_hooks_t hooks;
                         arith_t res;
                         int errcode;
-                        char *exp_str;
 
                         arg++; /* skip '+' */
                         *p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
                         debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
-
-                        exp_str = expand_pseudo_dquoted(arg);
-                        hooks.lookupvar = get_local_var_value;
-                        hooks.setvar = set_local_var_from_halves;
-                        hooks.endofname = endofname;
-                        res = arith(exp_str ? exp_str : arg, &errcode, &hooks);
-                        free(exp_str);
+                        res = expand_and_evaluate_arith(arg, &errcode);
 
                         if (errcode < 0) {
                                 const char *msg = "error in arithmetic";
@@ -2628,8 +2637,8 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
                                                 scan_t scan = pick_scan(exp_op, *exp_word, &match_at_left);
                                                 if (exp_op == *exp_word)        /* ## or %% */
                                                         exp_word++;
-                                                val = dyn_val = xstrdup(val);
-                                                loc = scan(dyn_val, exp_word, match_at_left);
+                                                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 */
@@ -2662,7 +2671,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
                                                 if (len == 0 || !val || beg >= strlen(val))
                                                         val = "";
                                                 else
-                                                        val = dyn_val = xstrndup(val + beg, len);
+                                                        val = to_be_freed = xstrndup(val + beg, len);
                                                 //bb_error_msg("val:'%s'", val);
                                         } else
 #endif
@@ -2699,13 +2708,16 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
                                         debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
                                                 (exp_save == ':') ? "true" : "false", use_word);
                                         if (use_word) {
+                                                to_be_freed = expand_pseudo_dquoted(exp_word);
+                                                if (to_be_freed)
+                                                        exp_word = to_be_freed;
                                                 if (exp_op == '?') {
-//TODO: how interactive bash aborts expansion mid-command?
                                                         /* mimic bash message */
                                                         die_if_script("%s: %s",
                                                                 var,
                                                                 exp_word[0] ? exp_word : "parameter null or not set"
                                                         );
+//TODO: how interactive bash aborts expansion mid-command?
                                                 } else {
                                                         val = exp_word;
                                                 }
@@ -2750,7 +2762,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char
                 if (val) {
                         o_addQstr(output, val, strlen(val));
                 }
-                free(dyn_val);
+                free(to_be_freed);
                 /* Do the check to avoid writing to a const string */
                 if (*p != SPECIAL_VAR_SYMBOL)
                         *p = SPECIAL_VAR_SYMBOL;