* nscd/mem.c (gc): Avoid stack overflow when allocating move list.cvs/fedora-glibc-20080518T1017

2 files changed, 18 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index e17090f990..d053ed080a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2008-05-17  Ulrich Drepper  <drepper@redhat.com>
 
+	* nscd/mem.c (gc): Avoid stack overflow when allocating move list.
+
 	* nscd/mem.c (gc): Correctly determine highest used array element
 	in mark.
 
diff --git a/nscd/mem.c b/nscd/mem.c
index bf3777d119..96ff03f0df 100644
--- a/nscd/mem.c
+++ b/nscd/mem.c
@@ -24,6 +24,7 @@
 #include <inttypes.h>
 #include <libintl.h>
 #include <limits.h>
+#include <obstack.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -157,6 +158,7 @@ gc (struct database_dyn *db)
       he = alloca (db->head->nentries * sizeof (struct hashentry *));
       he_data = alloca (db->head->nentries * sizeof (struct hashentry *));
       he_use_malloc = false;
+      stack_used += memory_needed;
     }
   else
     {
@@ -305,6 +307,10 @@ gc (struct database_dyn *db)
     size_t size;
     struct moveinfo *next;
   } *moves = NULL;
+#define obstack_chunk_alloc xmalloc
+#define obstack_chunk_free free
+  struct obstack ob;
+  obstack_init (&ob);
 
   while (byte < high)
     {
@@ -365,8 +371,14 @@ gc (struct database_dyn *db)
 	 displacement.  */
       ref_t disp = off_alloc - off_free;
 
-      struct moveinfo *new_move
-	= (struct moveinfo *) alloca (sizeof (*new_move));
+      struct moveinfo *new_move;
+      if (stack_used + sizeof (*new_move) <= MAX_STACK_USE)
+	{
+	  new_move = alloca (sizeof (*new_move));
+	  stack_used += sizeof (*new_move);
+	}
+      else
+	new_move = obstack_alloc (&ob, sizeof (*new_move));
       new_move->from = db->data + off_alloc;
       new_move->to = db->data + off_free;
       new_move->size = off_allocend - off_alloc;
@@ -526,6 +538,8 @@ gc (struct database_dyn *db)
     free (he);
   if (mark_use_malloc)
     free (mark);
+
+  obstack_free (&ob, NULL);
 }