hush: make expand_vars_to_list() a bit more sane

function                                             old     new   delta
append_str_maybe_ifs_split                             -      64     +64
expand_vars_to_list                                 1167    1139     -28
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/1 up/down: 64/-28)             Total: 36 bytes

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

1 files changed, 32 insertions, 28 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 92c79b8b6..b738d2fd8 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -5955,6 +5955,24 @@ static char *replace_pattern(char *val, const char *pattern, const char *repl, c
 }
 #endif /* BASH_PATTERN_SUBST */
 
+static int append_str_maybe_ifs_split(o_string *output, int *ended_in_ifs, int n,
+        int first_ch, const char *val)
+{
+        if (!(first_ch & 0x80)) { /* unquoted $VAR */
+                debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val,
+                                !!(output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
+                if (val && val[0])
+                        n = expand_on_ifs(ended_in_ifs, output, n, val);
+        } else { /* quoted "$VAR" */
+                output->has_quoted_part = 1;
+                debug_printf_expand("quoted '%s', output->o_escape:%d\n", val,
+                                !!(output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
+                if (val && val[0])
+                        o_addQstr(output, val);
+        }
+        return n;
+}
+
 /* Helper:
  * Handles <SPECIAL_VAR_SYMBOL>varname...<SPECIAL_VAR_SYMBOL> construct.
  */
@@ -6290,11 +6308,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
 
         while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
                 char first_ch;
-                char *to_be_freed = NULL;
                 const char *val = NULL;
-#if ENABLE_HUSH_TICK
-                o_string subst_result = NULL_O_STRING;
-#endif
 #if ENABLE_FEATURE_SH_MATH
                 char arith_buf[sizeof(arith_t)*3 + 2];
 #endif
@@ -6382,7 +6396,9 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
                         val = SPECIAL_VAR_SYMBOL_STR;
                         break;
 #if ENABLE_HUSH_TICK
-                case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
+                case '`': { /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
+                        o_string subst_result = NULL_O_STRING;
+
                         *p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
                         arg++;
                         /* Can't just stuff it into output o_string,
@@ -6392,8 +6408,10 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
                         G.last_exitcode = process_command_subs(&subst_result, arg);
                         G.expand_exitcode = G.last_exitcode;
                         debug_printf_subst("SUBST RES:%d '%s'\n", G.last_exitcode, subst_result.data);
-                        val = subst_result.data;
-                        goto store_val;
+                        n = append_str_maybe_ifs_split(output, &ended_in_ifs, n, first_ch, subst_result.data);
+                        o_free_unsafe(&subst_result);
+                        goto restore;
+                }
 #endif
 #if ENABLE_FEATURE_SH_MATH
                 case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
@@ -6409,37 +6427,23 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
                         break;
                 }
 #endif
-                default:
+                default: {
+                        char *to_be_freed;
                         val = expand_one_var(&to_be_freed, arg, &p);
- IF_HUSH_TICK(store_val:)
-                        if (!(first_ch & 0x80)) { /* unquoted $VAR */
-                                debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val,
-                                                !!(output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
-                                if (val && val[0]) {
-                                        n = expand_on_ifs(&ended_in_ifs, output, n, val);
-                                        val = NULL;
-                                }
-                        } else { /* quoted $VAR, val will be appended below */
-                                output->has_quoted_part = 1;
-                                debug_printf_expand("quoted '%s', output->o_escape:%d\n", val,
-                                                !!(output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
-                        }
-                        break;
+                        n = append_str_maybe_ifs_split(output, &ended_in_ifs, n, first_ch, val);
+                        free(to_be_freed);
+                        goto restore;
+                } /* default: */
                 } /* switch (char after <SPECIAL_VAR_SYMBOL>) */
 
                 if (val && val[0]) {
                         o_addQstr(output, val);
                 }
-                free(to_be_freed);
-
+ restore:
                 /* Restore NULL'ed SPECIAL_VAR_SYMBOL.
                  * Do the check to avoid writing to a const string. */
                 if (*p != SPECIAL_VAR_SYMBOL)
                         *p = SPECIAL_VAR_SYMBOL;
-
-#if ENABLE_HUSH_TICK
-                o_free(&subst_result);
-#endif
                 arg = ++p;
         } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */