hush: shrink and make more versatile error-reporting machinery

function                                             old     new   delta
syntax_error_unterm_ch                                 -      31     +31
syntax_error_unterm_str                                -      14     +14
parse_stream                                        2356    2361      +5
syntax_error_at                                       12      14      +2
syntax_error                                          25      27      +2
syntax_error_unterminated                             28       -     -28
expand_variables                                    2063    2031     -32
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 3/1 up/down: 54/-60)             Total: -6 bytes
   text    data     bss     dec     hex filename
  67278     197    3184   70659   11403 busybox_old
  67228     197    3184   70609   113d1 busybox_unstripped

1 files changed, 46 insertions, 39 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 41d65ff69..d6f765d6b 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -663,23 +663,25 @@ static void xxfree(void *ptr)
  * HUSH_DEBUG >= 2 prints line number in this file where it was detected.
  */
 #if HUSH_DEBUG < 2
-# define die_if_script(lineno, fmt, msg)       die_if_script(fmt, msg)
-# define syntax_error(lineno, msg)             syntax_error(msg)
-# define syntax_error_at(lineno, msg)          syntax_error_at(msg)
-# define syntax_error_unterminated(lineno, ch) syntax_error_unterminated(ch)
+# define die_if_script(lineno, fmt...)      die_if_script(fmt)
+# define syntax_error(lineno, msg)          syntax_error(msg)
+# define syntax_error_at(lineno, msg)       syntax_error_at(msg)
+# define syntax_error_unterm_ch(lineno, ch) syntax_error_unterm_ch(ch)
+# define syntax_error_unterm_str(lineno, s) syntax_error_unterm_str(s)
 #endif
 
-static void die_if_script(unsigned lineno, const char *fmt, const char *msg)
+static void die_if_script(unsigned lineno, const char *fmt, ...)
 {
-        void FAST_FUNC (*fp)(const char *s, ...) = bb_error_msg_and_die;
-#if ENABLE_HUSH_INTERACTIVE
-        if (G_interactive_fd)
-                fp = bb_error_msg;
-#endif
+        va_list p;
+
 #if HUSH_DEBUG >= 2
         bb_error_msg("hush.c:%u", lineno);
 #endif
-        fp(fmt, msg);
+        va_start(p, fmt);
+        bb_verror_msg(fmt, p, NULL);
+        va_end(p);
+        if (!G_interactive_fd)
+                xfunc_die();
 }
 
 static void syntax_error(unsigned lineno, const char *msg)
@@ -695,7 +697,7 @@ static void syntax_error_at(unsigned lineno, const char *msg)
         die_if_script(lineno, "syntax error at '%s'", msg);
 }
 
-static void syntax_error_unterminated(unsigned lineno, char ch)
+static void syntax_error_unterm_ch(unsigned lineno, char ch)
 {
         char msg[2];
         msg[0] = ch;
@@ -703,16 +705,23 @@ static void syntax_error_unterminated(unsigned lineno, char ch)
         die_if_script(lineno, "syntax error: unterminated %s", msg);
 }
 
+static void syntax_error_unterm_str(unsigned lineno, const char *s)
+{
+        die_if_script(lineno, "syntax error: unterminated %s", s);
+}
+
 #if HUSH_DEBUG < 2
 # undef die_if_script
 # undef syntax_error
 # undef syntax_error_at
-# undef syntax_error_unterminated
+# undef syntax_error_unterm_ch
+# undef syntax_error_unterm_str
 #else
-# define die_if_script(fmt, msg)       die_if_script(__LINE__, fmt, msg)
-# define syntax_error(msg)             syntax_error(__LINE__, msg)
-# define syntax_error_at(msg)          syntax_error_at(__LINE__, msg)
-# define syntax_error_unterminated(ch) syntax_error_unterminated(__LINE__, ch)
+# define die_if_script(fmt...)      die_if_script(__LINE__, fmt)
+# define syntax_error(msg)          syntax_error(__LINE__, msg)
+# define syntax_error_at(msg)       syntax_error_at(__LINE__, msg)
+# define syntax_error_unterm_ch(ch) syntax_error_unterm_ch(__LINE__, ch)
+# define syntax_error_unterm_str(s) syntax_error_unterm_str(__LINE__, s)
 #endif
 
 
@@ -1957,7 +1966,7 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
                                         msg = "expression recursion loop detected";
                                         break;
                                 }
-                                die_if_script(msg, NULL);
+                                die_if_script(msg);
                         }
                         debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res);
                         sprintf(arith_buf, arith_t_fmt, res);
@@ -2036,20 +2045,18 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
                                         debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
                                                 exp_null ? "true" : "false", exp_test);
                                         if (exp_test) {
-                                                if (exp_op == '?')
-//TODO: what does interactive bash
+                                                if (exp_op == '?') {
+//TODO: how interactive bash aborts expansion mid-command?
                                                         /* ${var?[error_msg_if_unset]} */
                                                         /* ${var:?[error_msg_if_unset_or_null]} */
                                                         /* mimic bash message */
-                                                        if (*exp_word) {
-                                                                char *msg = xasprintf("%s: %s", var, exp_word);
-                                                                die_if_script("%s", msg);
-                                                                free(msg);
-                                                        } else {
-                                                                die_if_script("%s: parameter null or not set", var);
-                                                        }
-                                                else
+                                                        die_if_script("%s: %s",
+                                                                var,
+                                                                exp_word[0] ? exp_word : "parameter null or not set"
+                                                        );
+                                                } else {
                                                         val = exp_word;
+                                                }
 
                                                 if (exp_op == '=') {
                                                         /* ${var=[word]} or ${var:=[word]} */
@@ -4487,7 +4494,7 @@ static int add_till_single_quote(o_string *dest, struct in_str *input)
         while (1) {
                 int ch = i_getch(input);
                 if (ch == EOF) {
-                        syntax_error_unterminated('\'');
+                        syntax_error_unterm_ch('\'');
                         return 1;
                 }
                 if (ch == '\'')
@@ -4501,7 +4508,7 @@ static int add_till_double_quote(o_string *dest, struct in_str *input)
         while (1) {
                 int ch = i_getch(input);
                 if (ch == EOF) {
-                        syntax_error_unterminated('"');
+                        syntax_error_unterm_ch('"');
                         return 1;
                 }
                 if (ch == '"')
@@ -4539,7 +4546,7 @@ static int add_till_backquote(o_string *dest, struct in_str *input)
         while (1) {
                 int ch = i_getch(input);
                 if (ch == EOF) {
-                        syntax_error_unterminated('`');
+                        syntax_error_unterm_ch('`');
                         return 1;
                 }
                 if (ch == '`')
@@ -4548,7 +4555,7 @@ static int add_till_backquote(o_string *dest, struct in_str *input)
                         /* \x. Copy both chars unless it is \` */
                         int ch2 = i_getch(input);
                         if (ch2 == EOF) {
-                                syntax_error_unterminated('`');
+                                syntax_error_unterm_ch('`');
                                 return 1;
                         }
                         if (ch2 != '`' && ch2 != '$' && ch2 != '\\')
@@ -4576,7 +4583,7 @@ static int add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl
         while (1) {
                 int ch = i_getch(input);
                 if (ch == EOF) {
-                        syntax_error_unterminated(')');
+                        syntax_error_unterm_ch(')');
                         return 1;
                 }
                 if (ch == '(')
@@ -4608,7 +4615,7 @@ static int add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl
                         /* \x. Copy verbatim. Important for  \(, \) */
                         ch = i_getch(input);
                         if (ch == EOF) {
-                                syntax_error_unterminated(')');
+                                syntax_error_unterm_ch(')');
                                 return 1;
                         }
                         o_addchr(dest, ch);
@@ -4726,7 +4733,7 @@ static int handle_dollar(o_string *as_string,
                                         break;
                                 default:
                                 case_default:
-                                        syntax_error("unterminated ${name}");
+                                        syntax_error_unterm_str("${name}");
                                         debug_printf_parse("handle_dollar return 1: unterminated ${name}\n");
                                         return 1;
                                 }
@@ -4831,7 +4838,7 @@ static int parse_stream_dquoted(o_string *as_string,
         }
         /* note: can't move it above ch == dquote_end check! */
         if (ch == EOF) {
-                syntax_error_unterminated('"');
+                syntax_error_unterm_ch('"');
                 debug_printf_parse("parse_stream_dquoted return 1: unterminated \"\n");
                 return 1;
         }
@@ -4954,7 +4961,7 @@ static struct pipe *parse_stream(char **pstring,
                         struct pipe *pi;
 
                         if (heredoc_cnt) {
-                                syntax_error("unterminated here document");
+                                syntax_error_unterm_str("here document");
                                 goto parse_error;
                         }
                         if (done_word(&dest, &ctx)) {
@@ -5043,7 +5050,7 @@ static struct pipe *parse_stream(char **pstring,
                                  * We require heredoc to be in enclosing {}/(),
                                  * if any.
                                  */
-                                syntax_error("unterminated here document");
+                                syntax_error_unterm_str("here document");
                                 goto parse_error;
                         }
                         if (done_word(&dest, &ctx)) {
@@ -5123,7 +5130,7 @@ static struct pipe *parse_stream(char **pstring,
                         while (1) {
                                 ch = i_getch(input);
                                 if (ch == EOF) {
-                                        syntax_error_unterminated('\'');
+                                        syntax_error_unterm_ch('\'');
                                         goto parse_error;
                                 }
                                 nommu_addchr(&ctx.as_string, ch);