3 files changed, 40 insertions, 32 deletions

diff --git a/shell/hush.c b/shell/hush.c
index b3ae73b9b..b612c80da 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2248,9 +2248,12 @@ static const char* FAST_FUNC get_local_var_value(const char *name)
         return NULL;
 }
 
+#if (ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT) \
+ || (ENABLE_HUSH_LINENO_VAR || ENABLE_HUSH_GETOPTS)
 static void handle_changed_special_names(const char *name, unsigned name_len)
 {
         if (ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT
+         && G_interactive_fd
          && name_len == 3 && name[0] == 'P' && name[1] == 'S'
         ) {
                 cmdedit_update_prompt();
@@ -2274,6 +2277,10 @@ static void handle_changed_special_names(const char *name, unsigned name_len)
 #endif
         }
 }
+#else
+/* Do not even bother evaluating arguments */
+# define handle_changed_special_names(...) ((void)0)
+#endif
 
 /* str holds "NAME=VAL" and is expected to be malloced.
  * We take ownership of it.
@@ -2289,6 +2296,7 @@ static int set_local_var(char *str, unsigned flags)
         char *free_me = NULL;
         char *eq_sign;
         int name_len;
+        int retval;
         unsigned local_lvl = (flags >> SETFLAG_VARLVL_SHIFT);
 
         eq_sign = strchr(str, '=');
@@ -2402,24 +2410,24 @@ static int set_local_var(char *str, unsigned flags)
 #endif
         if (flags & SETFLAG_EXPORT)
                 cur->flg_export = 1;
+        retval = 0;
         if (cur->flg_export) {
                 if (flags & SETFLAG_UNEXPORT) {
                         cur->flg_export = 0;
                         /* unsetenv was already done */
                 } else {
-                        int i;
                         debug_printf_env("%s: putenv '%s'/%u\n", __func__, cur->varstr, cur->var_nest_level);
-                        i = putenv(cur->varstr);
-                        /* only now we can free old exported malloced string */
-                        free(free_me);
-                        return i;
+                        retval = putenv(cur->varstr);
+                        /* fall through to "free(free_me)" -
+                         * only now we can free old exported malloced string
+                         */
                 }
         }
         free(free_me);
 
         handle_changed_special_names(cur->varstr, name_len - 1);
 
-        return 0;
+        return retval;
 }
 
 static void FAST_FUNC set_local_var_from_halves(const char *name, const char *val)
@@ -2492,6 +2500,11 @@ static void add_vars(struct variable *var)
                 } else {
                         debug_printf_env("%s: restoring variable '%s'/%u\n", __func__, var->varstr, var->var_nest_level);
                 }
+                /* Testcase (interactive):
+                 * f() { local PS1='\w \$ '; }; f
+                 * the below call is needed to notice restored PS1 when f returns.
+                 */
+                handle_changed_special_names(var->varstr, endofname(var->varstr) - var->varstr);
                 var = next;
         }
 }
@@ -4198,7 +4211,7 @@ static int done_word(struct parse_context *ctx)
 #if ENABLE_HUSH_LOOPS
         if (ctx->ctx_res_w == RES_FOR) {
                 if (ctx->word.has_quoted_part
-                 || !is_well_formed_var_name(command->argv[0], '\0')
+                 || endofname(command->argv[0])[0] != '\0'
                 ) {
                         /* bash says just "not a valid identifier" */
                         syntax_error("not a valid identifier in for");
@@ -5372,7 +5385,7 @@ static struct pipe *parse_stream(char **pstring,
                         if ((ctx.is_assignment == MAYBE_ASSIGNMENT
                             || ctx.is_assignment == WORD_IS_KEYWORD)
                          && ch == '='
-                         && is_well_formed_var_name(ctx.word.data, '=')
+                         && endofname(ctx.word.data)[0] == '='
                         ) {
                                 ctx.is_assignment = DEFINITELY_ASSIGNMENT;
                                 debug_printf_parse("ctx.is_assignment='%s'\n", assignment_flag[ctx.is_assignment]);
@@ -7598,10 +7611,10 @@ static int save_fd_on_redirect(int fd, int avoid_fd, struct squirrel **sqp)
                 avoid_fd = 9;
 
 #if ENABLE_HUSH_INTERACTIVE
-        if (fd == G.interactive_fd) {
+        if (fd == G_interactive_fd) {
                 /* Testcase: "ls -l /proc/$$/fd 255>&-" should work */
-                G.interactive_fd = xdup_CLOEXEC_and_close(G.interactive_fd, avoid_fd);
-                debug_printf_redir("redirect_fd %d: matches interactive_fd, moving it to %d\n", fd, G.interactive_fd);
+                G_interactive_fd = xdup_CLOEXEC_and_close(G_interactive_fd, avoid_fd);
+                debug_printf_redir("redirect_fd %d: matches interactive_fd, moving it to %d\n", fd, G_interactive_fd);
                 return 1; /* "we closed fd" */
         }
 #endif
@@ -7677,7 +7690,7 @@ static void restore_redirects(struct squirrel *sq)
                 free(sq);
         }
 
-        /* If moved, G.interactive_fd stays on new fd, not restoring it */
+        /* If moved, G_interactive_fd stays on new fd, not restoring it */
 }
 
 #if ENABLE_FEATURE_SH_STANDALONE && BB_MMU
@@ -7694,7 +7707,7 @@ static int internally_opened_fd(int fd, struct squirrel *sq)
         int i;
 
 #if ENABLE_HUSH_INTERACTIVE
-        if (fd == G.interactive_fd)
+        if (fd == G_interactive_fd)
                 return 1;
 #endif
         /* If this one of script's fds? */
@@ -7885,6 +7898,11 @@ static void remove_nested_vars(void)
                 *cur_pp = cur->next;
                 /* Free */
                 if (!cur->max_len) {
+                        /* Testcase (interactive):
+                         * f() { local PS1='\w \$ '; }; f
+                         * we should forget local PS1:
+                         */
+                        handle_changed_special_names(cur->varstr, endofname(cur->varstr) - cur->varstr);
                         debug_printf_env("freeing nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
                         free(cur->varstr);
                 }
@@ -10687,9 +10705,7 @@ static int helper_export_local(char **argv, unsigned flags)
 {
         do {
                 char *name = *argv;
-                char *name_end = strchrnul(name, '=');
-
-                /* So far we do not check that name is valid (TODO?) */
+                const char *name_end = endofname(name);
 
                 if (*name_end == '\0') {
                         struct variable *var, **vpp;
@@ -10747,8 +10763,15 @@ static int helper_export_local(char **argv, unsigned flags)
                          */
                         name = xasprintf("%s=", name);
                 } else {
+                        if (*name_end != '=') {
+                                bb_error_msg("'%s': bad variable name", name);
+                                /* do not parse following argv[]s: */
+                                return 1;
+                        }
                         /* (Un)exporting/making local NAME=VALUE */
                         name = xstrdup(name);
+                        /* Testcase: export PS1='\w \$ ' */
+                        unbackslash(name);
                 }
                 debug_printf_env("%s: set_local_var('%s')\n", __func__, name);
                 if (set_local_var(name, flags))
diff --git a/shell/shell_common.c b/shell/shell_common.c
index da3165329..e0582adfb 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -22,19 +22,6 @@
 const char defifsvar[] ALIGN1 = "IFS= \t\n";
 const char defoptindvar[] ALIGN1 = "OPTIND=1";
 
-
-int FAST_FUNC is_well_formed_var_name(const char *s, char terminator)
-{
-        if (!s || !(isalpha(*s) || *s == '_'))
-                return 0;
-
-        do
-                s++;
-        while (isalnum(*s) || *s == '_');
-
-        return *s == terminator;
-}
-
 /* read builtin */
 
 /* Needs to be interruptible: shell must handle traps and shell-special signals
@@ -70,7 +57,7 @@ shell_builtin_read(struct builtin_read_params *params)
         argv = params->argv;
         pp = argv;
         while (*pp) {
-                if (!is_well_formed_var_name(*pp, '\0')) {
+                if (endofname(*pp)[0] != '\0') {
                         /* Mimic bash message */
                         bb_error_msg("read: '%s': not a valid identifier", *pp);
                         return (const char *)(uintptr_t)1;
diff --git a/shell/shell_common.h b/shell/shell_common.h
index a1323021d..7b478f1df 100644
--- a/shell/shell_common.h
+++ b/shell/shell_common.h
@@ -26,8 +26,6 @@ extern const char defifsvar[] ALIGN1; /* "IFS= \t\n" */
 
 extern const char defoptindvar[] ALIGN1; /* "OPTIND=1" */
 
-int FAST_FUNC is_well_formed_var_name(const char *s, char terminator);
-
 /* Builtins */
 
 struct builtin_read_params {