hush: next small step towards functions

1 files changed, 53 insertions, 19 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 377f13aa4..6efc3073b 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -96,6 +96,12 @@
 #endif
 
 
+/* Keep unconditionally on for now */
+#define HUSH_DEBUG 1
+/* In progress... */
+#define ENABLE_HUSH_FUNCTIONS 0
+
+
 /* If you comment out one of these below, it will be #defined later
  * to perform debug printfs to stderr: */
 #define debug_printf(...)        do {} while (0)
@@ -218,8 +224,6 @@ void xxfree(void *ptr)
 #endif
 
 
-/* Keep unconditionally on for now */
-#define HUSH_DEBUG 1
 /* Do we support ANY keywords? */
 #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
 #define HAS_KEYWORDS 1
@@ -307,7 +311,7 @@ struct command {
         pid_t pid;                  /* 0 if exited */
         int assignment_cnt;         /* how many argv[i] are assignments? */
         smallint is_stopped;        /* is the command currently running? */
-        smallint subshell;          /* flag, non-zero if group must be forked */
+        smallint grp_type;
         struct pipe *group;         /* if non-NULL, this "prog" is {} group,
                                      * subshell, or a compound statement */
         char **argv;                /* command name and arguments */
@@ -319,6 +323,11 @@ struct command {
  * Example: argv[0]=='.^C*^C.' here: echo .$*.
  * References of the form ^C`cmd arg^C are `cmd arg` substitutions.
  */
+#define GRP_NORMAL   0
+#define GRP_SUBSHELL 1
+#if ENABLE_HUSH_FUNCTIONS
+#define GRP_FUNCTION 2
+#endif
 
 struct pipe {
         struct pipe *next;
@@ -1016,12 +1025,14 @@ static void o_addstr_duplicate_backslash(o_string *o, const char *str, int len)
 static void o_addqchr(o_string *o, int ch)
 {
         int sz = 1;
-        if (strchr("*?[\\", ch)) {
+        char *found = strchr("*?[\\", ch);
+        if (found)
                 sz++;
+        o_grow_by(o, sz);
+        if (found) {
                 o->data[o->length] = '\\';
                 o->length++;
         }
-        o_grow_by(o, sz);
         o->data[o->length] = ch;
         o->length++;
         o->data[o->length] = '\0';
@@ -1834,7 +1845,15 @@ static int run_pipe(struct pipe *pi)
          */
         command = &(pi->cmds[0]);
 
-        if (single_and_fg && command->group && command->subshell == 0) {
+#if ENABLE_HUSH_FUNCTIONS
+        if (single_and_fg && command->group && command->grp_type == GRP_FUNCTION) {
+                /* We "execute" function definition */
+                bb_error_msg("here we ought to remember function definition, and go on");
+                return EXIT_SUCCESS;
+        }
+#endif
+
+        if (single_and_fg && command->group && command->grp_type == GRP_NORMAL) {
                 debug_printf("non-subshell grouping\n");
                 setup_redirects(command, squirrel);
                 debug_printf_exec(": run_list\n");
@@ -2023,7 +2042,7 @@ static int run_pipe(struct pipe *pi)
 #ifndef debug_print_tree
 static void debug_print_tree(struct pipe *pi, int lvl)
 {
-        static const char *PIPE[] = {
+        static const char *const PIPE[] = {
                 [PIPE_SEQ] = "SEQ",
                 [PIPE_AND] = "AND",
                 [PIPE_OR ] = "OR" ,
@@ -2057,6 +2076,13 @@ static void debug_print_tree(struct pipe *pi, int lvl)
                 [RES_XXXX ] = "XXXX" ,
                 [RES_SNTX ] = "SNTX" ,
         };
+        static const char *const GRPTYPE[] = {
+                "()",
+                "{}",
+#if ENABLE_HUSH_FUNCTIONS
+                "func()",
+#endif
+        };
 
         int pin, prn;
 
@@ -2072,7 +2098,7 @@ static void debug_print_tree(struct pipe *pi, int lvl)
                         fprintf(stderr, "%*s prog %d assignment_cnt:%d", lvl*2, "", prn, command->assignment_cnt);
                         if (command->group) {
                                 fprintf(stderr, " group %s: (argv=%p)\n",
-                                                (command->subshell ? "()" : "{}"),
+                                                GRPTYPE[command->grp_type],
                                                 argv);
                                 debug_print_tree(command->group, lvl+1);
                                 prn++;
@@ -2443,7 +2469,7 @@ static int free_pipe(struct pipe *pi, int indent)
                         free_strings(command->argv);
                         command->argv = NULL;
                 } else if (command->group) {
-                        debug_printf_clean("%s   begin group (subshell:%d)\n", indenter(indent), command->subshell);
+                        debug_printf_clean("%s   begin group (grp_type:%d)\n", indenter(indent), command->grp_type);
                         ret_code = free_pipe_list(command->group, indent+3);
                         debug_printf_clean("%s   end group\n", indenter(indent));
                 } else {
@@ -2572,7 +2598,6 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
 #if ENABLE_HUSH_TICK
                 o_string subst_result = NULL_O_STRING;
 #endif
-
                 o_addstr(output, arg, p - arg);
                 debug_print_list("expand_vars_to_list[1]", output, n);
                 arg = ++p;
@@ -3100,7 +3125,7 @@ static int reserved_word(o_string *word, struct parse_context *ctx)
                 done_pipe(ctx, PIPE_SEQ);
                 old = ctx->stack;
                 old->command->group = ctx->list_head;
-                old->command->subshell = 0;
+                old->command->grp_type = GRP_NORMAL;
                 *ctx = *old;   /* physical copy */
                 free(old);
         }
@@ -3461,15 +3486,24 @@ static int process_command_subs(o_string *dest,
 static int parse_group(o_string *dest, struct parse_context *ctx,
         struct in_str *input, int ch)
 {
-        /* NB: parse_group may create and use its own o_string,
-         * without any code changes. It just so happens that code is smaller
-         * if we (ab)use caller's one. */
+        /* dest contains characters seen prior to ( or {.
+         * Typically it's empty, but for functions defs,
+         * it contains function name (without '()'). */
         int rcode;
         const char *endch = NULL;
         struct parse_context sub;
         struct command *command = ctx->command;
 
         debug_printf_parse("parse_group entered\n");
+#if ENABLE_HUSH_FUNCTIONS
+        if (ch == 'F') { /* function definition? */
+                bb_error_msg("aha '%s' is a function, parsing it...", dest->data);
+                //command->fname = dest->data;
+                command->grp_type = GRP_FUNCTION;
+//TODO: review every o_reset() location... do they handle all o_string fields correctly?
+                memset(dest, 0, sizeof(*dest));
+        }
+#endif
         if (command->argv /* word [word](... */
          || dest->length /* word(... */
          || dest->nonnull /* ""(... */
@@ -3482,11 +3516,8 @@ static int parse_group(o_string *dest, struct parse_context *ctx,
         endch = "}";
         if (ch == '(') {
                 endch = ")";
-                command->subshell = 1;
+                command->grp_type = GRP_SUBSHELL;
         }
-//TODO  if (ch == 'F') { /* function definition */
-//              command->subshell = 2;
-//      }
         rcode = parse_stream(dest, &sub, input, endch);
         if (rcode == 0) {
                 done_word(dest, &sub); /* finish off the final word in the subcontext */
@@ -3988,16 +4019,18 @@ static int parse_stream(o_string *dest, struct parse_context *ctx,
                                 continue;
                         }
 #endif
-#if 0 /* TODO: implement functions */
+#if ENABLE_HUSH_FUNCTIONS
                         if (dest->length != 0 /* not just () but word() */
                          && dest->nonnull == 0 /* not a"b"c() */
                          && ctx->command->argv == NULL /* it's the first word */
+//TODO: "func ( ) {...}" - note spaces - is valid format too in bash
                          && i_peek(input) == ')'
                          && !match_reserved_word(dest)
                         ) {
                                 bb_error_msg("seems like a function definition");
                                 i_getch(input);
                                 do {
+//TODO: do it properly.
                                         ch = i_getch(input);
                                 } while (ch == ' ' || ch == '\n');
                                 if (ch != '{') {
@@ -4005,6 +4038,7 @@ static int parse_stream(o_string *dest, struct parse_context *ctx,
                                         debug_printf_parse("parse_stream return 1\n");
                                         return 1;
                                 }
+                                ch = 'F'; /* magic value */
                         }
 #endif
                 case '{':