ash: [VAR] Add localvars nesting

Upstream commit:

    Date: Mon, 24 May 2010 15:31:27 +0800
    [VAR] Add localvars nesting

    This patch adds localvars nesting infrastructure so we can reuse
    the localvars mechanism for command evaluation.

    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

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

1 files changed, 44 insertions, 13 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 915e86167..8bef78546 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9167,7 +9167,12 @@ optschanged(void)
 #endif
 }
 
-static struct localvar *localvars;
+struct localvar_list {
+        struct localvar_list *next;
+        struct localvar *lv;
+};
+
+static struct localvar_list *localvar_stack;
 
 /*
  * Called after a function returns.
@@ -9176,11 +9181,19 @@ static struct localvar *localvars;
 static void
 poplocalvars(void)
 {
-        struct localvar *lvp;
+        struct localvar_list *ll;
+        struct localvar *lvp, *next;
         struct var *vp;
 
-        while ((lvp = localvars) != NULL) {
-                localvars = lvp->next;
+        INT_OFF;
+        ll = localvar_stack;
+        localvar_stack = ll->next;
+
+        next = ll->lv;
+        free(ll);
+
+        while ((lvp = next) != NULL) {
+                next = lvp->next;
                 vp = lvp->vp;
                 TRACE(("poplocalvar %s\n", vp ? vp->var_text : "-"));
                 if (vp == NULL) {       /* $- saved */
@@ -9199,19 +9212,34 @@ poplocalvars(void)
                 }
                 free(lvp);
         }
+        INT_ON;
+}
+
+/*
+ * Create a new localvar environment.
+ */
+static void
+pushlocalvars(void)
+{
+        struct localvar_list *ll;
+
+        INT_OFF;
+        ll = ckzalloc(sizeof(*ll));
+        /*ll->lv = NULL; - zalloc did it */
+        ll->next = localvar_stack;
+        localvar_stack = ll;
+        INT_ON;
 }
 
 static int
 evalfun(struct funcnode *func, int argc, char **argv, int flags)
 {
         volatile struct shparam saveparam;
-        struct localvar *volatile savelocalvars;
         struct jmploc *volatile savehandler;
         struct jmploc jmploc;
         int e;
 
         saveparam = shellparam;
-        savelocalvars = localvars;
         savehandler = exception_handler;
         e = setjmp(jmploc.loc);
         if (e) {
@@ -9219,7 +9247,6 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
         }
         INT_OFF;
         exception_handler = &jmploc;
-        localvars = NULL;
         shellparam.malloced = 0;
         func->count++;
         funcnest++;
@@ -9230,13 +9257,13 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
         shellparam.optind = 1;
         shellparam.optoff = -1;
 #endif
+        pushlocalvars();
         evaltree(func->n.narg.next, flags & EV_TESTED);
+        poplocalvars();
  funcdone:
         INT_OFF;
         funcnest--;
         freefunc(func);
-        poplocalvars();
-        localvars = savelocalvars;
         freeparam(&shellparam);
         shellparam = saveparam;
         exception_handler = savehandler;
@@ -9265,7 +9292,7 @@ mklocal(char *name)
          * x=0; f() { local x=1; echo $x; local x; echo $x; }; f; echo $x
          * x=0; f() { local x=1; echo $x; local x=2; echo $x; }; f; echo $x
          */
-        lvp = localvars;
+        lvp = localvar_stack->lv;
         while (lvp) {
                 if (lvp->vp && varcmp(lvp->vp->var_text, name) == 0) {
                         if (eq)
@@ -9310,8 +9337,8 @@ mklocal(char *name)
                 }
         }
         lvp->vp = vp;
-        lvp->next = localvars;
-        localvars = lvp;
+        lvp->next = localvar_stack->lv;
+        localvar_stack->lv = lvp;
  ret:
         INT_ON;
 }
@@ -9324,7 +9351,7 @@ localcmd(int argc UNUSED_PARAM, char **argv)
 {
         char *name;
 
-        if (!funcnest)
+        if (!localvar_stack)
                 ash_msg_and_raise_error("not in a function");
 
         argv = argptr;
@@ -13570,6 +13597,10 @@ reset(void)
         /* from redir.c: */
         while (redirlist)
                 popredir(/*drop:*/ 0, /*restore:*/ 0);
+
+        /* from var.c: */
+        while (localvar_stack)
+                poplocalvars();
 }
 
 #if PROFILE