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>

diff --git a/shell/ash.c b/shell/ash.c
index 915e86167a9878b4d5bef256d06c616721c578d6..8bef78546bda573d5a9fc4fc88ef94790b2fb77f 100644 (file)
--- 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