[VAR] Fix poplocalvar on abnormal exit from function

The new localvar code broke the abnormal exit from functions
and built-ins by not restoring the original localvar state.

This patch fixes this by storing the previous localvar state so
that we always unwind correctly in case of an abnormal exit.

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

3 files changed, 18 insertions, 6 deletions

diff --git a/src/eval.c b/src/eval.c
index a6981a9..2cd931b 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -681,6 +681,7 @@ evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
 evalcommand(union node *cmd, int flags)
 #endif
 {
+	struct localvar_list *localvar_stop;
 	struct stackmark smark;
 	union node *argp;
 	struct arglist arglist;
@@ -703,7 +704,7 @@ evalcommand(union node *cmd, int flags)
 	/* First expand the arguments. */
 	TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
 	setstackmark(&smark);
-	pushlocalvars();
+	localvar_stop = pushlocalvars();
 	back_exitstatus = 0;
 
 	cmdentry.cmdtype = CMDBUILTIN;
@@ -837,7 +838,6 @@ bail:
 			if (forkshell(jp, cmd, FORK_FG) != 0) {
 				exitstatus = waitforjob(jp);
 				INTON;
-				poplocalvars(0);
 				break;
 			}
 			FORCEINTON;
@@ -878,6 +878,7 @@ raise:
 
 out:
 	popredir(execcmd);
+	unwindlocalvars(localvar_stop);
 	if (lastarg)
 		/* dsl: I think this is intended to be used to support
 		 * '_' in 'vi' command mode during line editing...
diff --git a/src/var.c b/src/var.c
index 40bd3fd..f456fbd 100644
--- a/src/var.c
+++ b/src/var.c
@@ -144,8 +144,7 @@ INIT {
 }
 
 RESET {
-	while (localvar_stack)
-		poplocalvars(0);
+	unwindlocalvars(0);
 }
 #endif
 
@@ -570,7 +569,7 @@ poplocalvars(int keep)
 /*
  * Create a new localvar environment.
  */
-void pushlocalvars(void)
+struct localvar_list *pushlocalvars(void)
 {
 	struct localvar_list *ll;
 
@@ -580,6 +579,15 @@ void pushlocalvars(void)
 	ll->next = localvar_stack;
 	localvar_stack = ll;
 	INTON;
+
+	return ll->next;
+}
+
+
+void unwindlocalvars(struct localvar_list *stop)
+{
+	while (localvar_stack != stop)
+		poplocalvars(0);
 }
 
 
diff --git a/src/var.h b/src/var.h
index ef6d583..7e7e505 100644
--- a/src/var.h
+++ b/src/var.h
@@ -69,6 +69,8 @@ struct localvar {
 	const char *text;		/* saved text */
 };
 
+struct localvar_list;
+
 
 extern struct localvar *localvars;
 extern struct var varinit[];
@@ -139,8 +141,9 @@ int showvars(const char *, int, int);
 int exportcmd(int, char **);
 int localcmd(int, char **);
 void mklocal(char *);
-void pushlocalvars(void);
+struct localvar_list *pushlocalvars(void);
 void poplocalvars(int);
+void unwindlocalvars(struct localvar_list *stop);
 int unsetcmd(int, char **);
 void unsetvar(const char *);
 int varcmp(const char *, const char *);