hush: enable NOMMU re-execution logic. Some testsuite entries

 fail on NOMMU. Before it was much worse.
 No regressions on MMU, size:

function                                             old     new   delta
handle_dollar                                        626     632      +6
run_list                                            2018    2022      +4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 10/0)               Total: 10 bytes

1 files changed, 91 insertions, 22 deletions

diff --git a/shell/hush.c b/shell/hush.c
index ac3480578..0313cfd78 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2329,6 +2329,16 @@ static void pseudo_exec_argv(nommu_save_t *nommu_save,
         _exit(EXIT_FAILURE);
 }
 
+static void re_execute_shell(const char *s) NORETURN;
+static void re_execute_shell(const char *s)
+{
+//TODO: pass non-exported variables, traps, and functions
+        debug_printf_exec("re_execute_shell pid:%d cmd:'%s'", getpid(), s);
+        execl(bb_busybox_exec_path, "hush", "-c", s, NULL);
+//TODO: fallback for init=/bin/hush?
+        _exit(127);
+}
+
 static int run_list(struct pipe *pi);
 
 /* Called after [v]fork() in run_pipe()
@@ -2360,8 +2370,7 @@ static void pseudo_exec(nommu_save_t *nommu_save,
                  * since this process is about to exit */
                 _exit(rcode);
 #else
-                bb_error_msg_and_die("NOMMU TODO: re-exec '%s'",
-                                command->group_as_string);
+                re_execute_shell(command->group_as_string);
 #endif
         }
 
@@ -3831,9 +3840,7 @@ static FILE *generate_stream_from_string(const char *s)
          * huge=`cat TESTFILE` # was blocking here forever
          * echo OK
          */
-//TODO: pass non-exported variables, traps, and functions
-                execl(bb_busybox_exec_path, "hush", "-c", s, NULL);
-                _exit(127);
+                re_execute_shell(s);
 #endif
         }
 
@@ -4071,7 +4078,13 @@ static void add_till_closing_paren(o_string *dest, struct in_str *input, bool db
 #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */
 
 /* Return code: 0 for OK, 1 for syntax error */
-static int handle_dollar(o_string *dest, struct in_str *input)
+#if BB_MMU
+#define handle_dollar(ctx, dest, input) \
+        handle_dollar(dest, input)
+#endif
+static int handle_dollar(struct parse_context *ctx,
+                o_string *dest,
+                struct in_str *input)
 {
         int expansion;
         int ch = i_peek(input);  /* first character after the $ */
@@ -4079,7 +4092,10 @@ static int handle_dollar(o_string *dest, struct in_str *input)
 
         debug_printf_parse("handle_dollar entered: ch='%c'\n", ch);
         if (isalpha(ch)) {
-                i_getch(input);
+                ch = i_getch(input);
+#if !BB_MMU
+                o_addchr(&ctx->as_string, ch);
+#endif
  make_var:
                 o_addchr(dest, SPECIAL_VAR_SYMBOL);
                 while (1) {
@@ -4089,12 +4105,18 @@ static int handle_dollar(o_string *dest, struct in_str *input)
                         ch = i_peek(input);
                         if (!isalnum(ch) && ch != '_')
                                 break;
-                        i_getch(input);
+                        ch = i_getch(input);
+#if !BB_MMU
+                        o_addchr(&ctx->as_string, ch);
+#endif
                 }
                 o_addchr(dest, SPECIAL_VAR_SYMBOL);
         } else if (isdigit(ch)) {
  make_one_char_var:
-                i_getch(input);
+                ch = i_getch(input);
+#if !BB_MMU
+                o_addchr(&ctx->as_string, ch);
+#endif
                 o_addchr(dest, SPECIAL_VAR_SYMBOL);
                 debug_printf_parse(": '%c'\n", ch);
                 o_addchr(dest, ch | quote_mask);
@@ -4111,13 +4133,19 @@ static int handle_dollar(o_string *dest, struct in_str *input)
                 bool first_char, all_digits;
 
                 o_addchr(dest, SPECIAL_VAR_SYMBOL);
-                i_getch(input);
+                ch = i_getch(input);
+#if !BB_MMU
+                o_addchr(&ctx->as_string, ch);
+#endif
                 /* XXX maybe someone will try to escape the '}' */
                 expansion = 0;
                 first_char = true;
                 all_digits = false;
                 while (1) {
                         ch = i_getch(input);
+#if !BB_MMU
+                        o_addchr(&ctx->as_string, ch);
+#endif
                         if (ch == '}')
                                 break;
 
@@ -4183,10 +4211,16 @@ static int handle_dollar(o_string *dest, struct in_str *input)
                 break;
         }
         case '(': {
-                i_getch(input);
+                ch = i_getch(input);
+#if !BB_MMU
+                o_addchr(&ctx->as_string, ch);
+#endif
 #if ENABLE_SH_MATH_SUPPORT
                 if (i_peek(input) == '(') {
-                        i_getch(input);
+                        ch = i_getch(input);
+#if !BB_MMU
+                        o_addchr(&ctx->as_string, ch);
+#endif
                         o_addchr(dest, SPECIAL_VAR_SYMBOL);
                         o_addchr(dest, /*quote_mask |*/ '+');
                         add_till_closing_paren(dest, input, true);
@@ -4205,7 +4239,10 @@ static int handle_dollar(o_string *dest, struct in_str *input)
                 break;
         }
         case '_':
-                i_getch(input);
+                ch = i_getch(input);
+#if !BB_MMU
+                o_addchr(&ctx->as_string, ch);
+#endif
                 ch = i_peek(input);
                 if (isalnum(ch)) { /* it's $_name or $_123 */
                         ch = '_';
@@ -4281,7 +4318,7 @@ static int parse_stream_dquoted(struct parse_context *ctx,
                 goto again;
         }
         if (ch == '$') {
-                if (handle_dollar(dest, input) != 0) {
+                if (handle_dollar(ctx, dest, input) != 0) {
                         debug_printf_parse("parse_stream_dquoted return 1: "
                                         "handle_dollar returned non-0\n");
                         return 1;
@@ -4477,7 +4514,12 @@ static struct pipe *parse_stream(char **pstring,
                                         if (ch == EOF || ch == '\n')
                                                 break;
                                         i_getch(input);
+                                        /* note: we do not add it to &ctx.as_string */
                                 }
+#if !BB_MMU
+//TODO: go back one char?
+                                o_addchr(&ctx.as_string, '\n');
+#endif
                         } else {
                                 o_addQchr(&dest, ch);
                         }
@@ -4488,10 +4530,15 @@ static struct pipe *parse_stream(char **pstring,
                                 goto parse_error;
                         }
                         o_addchr(&dest, '\\');
-                        o_addchr(&dest, i_getch(input));
+                        ch = i_getch(input);
+                        o_addchr(&dest, ch);
+#if !BB_MMU
+                        o_addchr(&ctx.as_string, ch);
+#endif
                         break;
                 case '$':
-                        if (handle_dollar(&dest, input) != 0) {
+//NOMMU TODO!
+                        if (handle_dollar(&ctx, &dest, input) != 0) {
                                 debug_printf_parse("parse_stream parse error: "
                                         "handle_dollar returned non-0\n");
                                 goto parse_error;
@@ -4505,6 +4552,9 @@ static struct pipe *parse_stream(char **pstring,
                                         syntax("unterminated '");
                                         goto parse_error;
                                 }
+#if !BB_MMU
+                                o_addchr(&ctx.as_string, ch);
+#endif
                                 if (ch == '\'')
                                         break;
                                 if (dest.o_assignment == NOT_ASSIGNMENT)
@@ -4538,7 +4588,10 @@ static struct pipe *parse_stream(char **pstring,
                         redir_style = REDIRECT_OVERWRITE;
                         if (next == '>') {
                                 redir_style = REDIRECT_APPEND;
-                                i_getch(input);
+                                ch = i_getch(input);
+#if !BB_MMU
+                                o_addchr(&ctx.as_string, ch);
+#endif
                         }
 #if 0
                         else if (next == '(') {
@@ -4556,10 +4609,16 @@ static struct pipe *parse_stream(char **pstring,
                         redir_style = REDIRECT_INPUT;
                         if (next == '<') {
                                 redir_style = REDIRECT_HEREIS;
-                                i_getch(input);
+                                ch = i_getch(input);
+#if !BB_MMU
+                                o_addchr(&ctx.as_string, ch);
+#endif
                         } else if (next == '>') {
                                 redir_style = REDIRECT_IO;
-                                i_getch(input);
+                                ch = i_getch(input);
+#if !BB_MMU
+                                o_addchr(&ctx.as_string, ch);
+#endif
                         }
 #if 0
                         else if (next == '(') {
@@ -4584,7 +4643,10 @@ static struct pipe *parse_stream(char **pstring,
                                 ch = i_peek(input);
                                 if (ch != ';')
                                         break;
-                                i_getch(input);
+                                ch = i_getch(input);
+#if !BB_MMU
+                                o_addchr(&ctx.as_string, ch);
+#endif
                                 if (ctx.ctx_res_w == RES_CASEI) {
                                         ctx.ctx_dsemicolon = 1;
                                         ctx.ctx_res_w = RES_MATCH;
@@ -4602,7 +4664,10 @@ static struct pipe *parse_stream(char **pstring,
                                 goto parse_error;
                         }
                         if (next == '&') {
-                                i_getch(input);
+                                ch = i_getch(input);
+#if !BB_MMU
+                                o_addchr(&ctx.as_string, ch);
+#endif
                                 done_pipe(&ctx, PIPE_AND);
                         } else {
                                 done_pipe(&ctx, PIPE_BG);
@@ -4617,7 +4682,10 @@ static struct pipe *parse_stream(char **pstring,
                                 break; /* we are in case's "word | word)" */
 #endif
                         if (next == '|') { /* || */
-                                i_getch(input);
+                                ch = i_getch(input);
+#if !BB_MMU
+                                o_addchr(&ctx.as_string, ch);
+#endif
                                 done_pipe(&ctx, PIPE_OR);
                         } else {
                                 /* we could pick up a file descriptor choice here
@@ -4647,6 +4715,7 @@ static struct pipe *parse_stream(char **pstring,
                         ) {
                                 bb_error_msg("seems like a function definition");
                                 i_getch(input);
+//if !BB_MMU o_addchr(&ctx.as_string...
                                 do {
 //TODO: do it properly.
                                         ch = i_getch(input);