hush: fix "unset PS1/PS2", and put them into initial variable set

"unset PS1/PS2" causes prompts to be empty strings

function                                             old     new   delta
hush_main                                           1031    1089     +58
goto_new_line                                         27      33      +6
fgetc_interactive                                    244     245      +1
unset_local_var                                      155     149      -6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/1 up/down: 65/-6)              Total: 59 bytes

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

1 files changed, 35 insertions, 29 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 971a16aff..34d905397 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -828,7 +828,7 @@ struct globals {
          * _AND_ if we decided to act interactively */
         int interactive_fd;
         const char *PS1;
-        const char *PS2;
+        IF_FEATURE_EDITING_FANCY_PROMPT(const char *PS2;)
 # define G_interactive_fd (G.interactive_fd)
 #else
 # define G_interactive_fd 0
@@ -1394,7 +1394,7 @@ static void syntax_error_unexpected_ch(unsigned lineno UNUSED_PARAM, int ch)
 #endif
 
 
-#if ENABLE_HUSH_INTERACTIVE
+#if ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT
 static void cmdedit_update_prompt(void);
 #else
 # define cmdedit_update_prompt() ((void)0)
@@ -2125,7 +2125,9 @@ static const char* FAST_FUNC get_local_var_value(const char *name)
 
 static void handle_changed_special_names(const char *name, unsigned name_len)
 {
-        if (name_len == 3 && name[0] == 'P' && name[1] == 'S') {
+        if (ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT
+         && name_len == 3 && name[0] == 'P' && name[1] == 'S'
+        ) {
                 cmdedit_update_prompt();
                 return;
         }
@@ -2305,9 +2307,6 @@ static int unset_local_var_len(const char *name, int name_len)
         struct variable *cur;
         struct variable **cur_pp;
 
-        if (!name)
-                return EXIT_SUCCESS;
-
         cur_pp = &G.top_var;
         while ((cur = *cur_pp) != NULL) {
                 if (strncmp(cur->varstr, name, name_len) == 0
@@ -2321,17 +2320,18 @@ static int unset_local_var_len(const char *name, int name_len)
                         *cur_pp = cur->next;
                         debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
                         bb_unsetenv(cur->varstr);
-
-                        handle_changed_special_names(name, name_len);
-
                         if (!cur->max_len)
                                 free(cur->varstr);
                         free(cur);
 
-                        return EXIT_SUCCESS;
+                        break;
                 }
                 cur_pp = &cur->next;
         }
+
+        /* Handle "unset PS1" et al even if did not find the variable to unset */
+        handle_changed_special_names(name, name_len);
+
         return EXIT_SUCCESS;
 }
 
@@ -2459,36 +2459,36 @@ static void reinit_unicode_for_hush(void)
  *      \
  * It exercises a lot of corner cases.
  */
+# if ENABLE_FEATURE_EDITING_FANCY_PROMPT
 static void cmdedit_update_prompt(void)
 {
-        if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
-                G.PS1 = get_local_var_value("PS1");
-                if (G.PS1 == NULL)
-                        G.PS1 = "\\w \\$ ";
-                G.PS2 = get_local_var_value("PS2");
-        } else {
-                G.PS1 = NULL;
-        }
+        G.PS1 = get_local_var_value("PS1");
+        if (G.PS1 == NULL)
+                G.PS1 = "";
+        G.PS2 = get_local_var_value("PS2");
         if (G.PS2 == NULL)
-                G.PS2 = "> ";
+                G.PS2 = "";
 }
+# endif
 static const char *setup_prompt_string(int promptmode)
 {
         const char *prompt_str;
+
         debug_printf("setup_prompt_string %d ", promptmode);
-        if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
-                /* Set up the prompt */
-                if (promptmode == 0) { /* PS1 */
+
+        IF_FEATURE_EDITING_FANCY_PROMPT(    prompt_str = G.PS2;)
+        IF_NOT_FEATURE_EDITING_FANCY_PROMPT(prompt_str = "> ";)
+        if (promptmode == 0) { /* PS1 */
+                if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
+                        /* No fancy prompts supported, (re)generate "CURDIR $ " by hand */
                         free((char*)G.PS1);
                         /* bash uses $PWD value, even if it is set by user.
                          * It uses current dir only if PWD is unset.
                          * We always use current dir. */
                         G.PS1 = xasprintf("%s %c ", get_cwd(0), (geteuid() != 0) ? '$' : '#');
-                        prompt_str = G.PS1;
-                } else
-                        prompt_str = G.PS2;
-        } else
-                prompt_str = (promptmode == 0) ? G.PS1 : G.PS2;
+                }
+                prompt_str = G.PS1;
+        }
         debug_printf("prompt_str '%s'\n", prompt_str);
         return prompt_str;
 }
@@ -9207,6 +9207,14 @@ int hush_main(int argc, char **argv)
         /* Export PWD */
         set_pwd_var(SETFLAG_EXPORT);
 
+#if ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT
+        /* Set (but not export) PS1/2 unless already set */
+        if (!get_local_var_value("PS1"))
+                set_local_var_from_halves("PS1", "\\w \\$ ");
+        if (!get_local_var_value("PS2"))
+                set_local_var_from_halves("PS2", "> ");
+#endif
+
 #if BASH_HOSTNAME_VAR
         /* Set (but not export) HOSTNAME unless already set */
         if (!get_local_var_value("HOSTNAME")) {
@@ -9245,8 +9253,6 @@ int hush_main(int argc, char **argv)
          * OPTERR=1
          * OPTIND=1
          * IFS=$' \t\n'
-         * PS1='\s-\v\$ '
-         * PS2='> '
          * PS4='+ '
          */
 #endif