1 files changed, 45 insertions, 3 deletions

diff --git a/source4/heimdal/lib/krb5/store_emem.c b/source4/heimdal/lib/krb5/store_emem.c
index 8a587600fd..4be89b6564 100644
--- a/source4/heimdal/lib/krb5/store_emem.c
+++ b/source4/heimdal/lib/krb5/store_emem.c
@@ -34,8 +34,6 @@
 #include "krb5_locl.h"
 #include "store-int.h"
 
-RCSID("$Id$");
-
 typedef struct emem_storage{
     unsigned char *base;
     size_t size;
@@ -67,7 +65,7 @@ emem_store(krb5_storage *sp, const void *data, size_t size)
 	    sz *= 2;
 	base = realloc(s->base, sz);
 	if(base == NULL)
-	    return 0;
+	    return -1;
 	s->size = sz;
 	s->base = base;
 	s->ptr = (unsigned char*)base + off;
@@ -104,6 +102,34 @@ emem_seek(krb5_storage *sp, off_t offset, int whence)
     return s->ptr - s->base;
 }
 
+static int
+emem_trunc(krb5_storage *sp, off_t offset)
+{
+    emem_storage *s = (emem_storage*)sp->data;
+    /*
+     * If offset is larget then current size, or current size is
+     * shrunk more then half of the current size, adjust buffer.
+     */
+    if (offset > s->size || (s->size / 2) > offset) {
+	void *base;
+	size_t off;
+	off = s->ptr - s->base;
+	base = realloc(s->base, offset);
+	if(base == NULL)
+	    return ENOMEM;
+	if (offset > s->size)
+	    memset((char *)base + s->size, 0, offset - s->size);
+	s->size = offset;
+	s->base = base;
+	s->ptr = (unsigned char *)base + off;
+    }
+    s->len = offset;
+    if ((s->ptr - s->base) > offset)
+	s->ptr = s->base + offset;
+    return 0;
+}
+
+
 static void
 emem_free(krb5_storage *sp)
 {
@@ -112,6 +138,21 @@ emem_free(krb5_storage *sp)
     free(s->base);
 }
 
+/**
+ * Create a elastic (allocating) memory storage backend. Memory is
+ * allocated on demand. Free returned krb5_storage with
+ * krb5_storage_free().
+ *
+ * @return A krb5_storage on success, or NULL on out of memory error.
+ *
+ * @ingroup krb5_storage
+ *
+ * @sa krb5_storage_from_mem()
+ * @sa krb5_storage_from_readonly_mem()
+ * @sa krb5_storage_from_fd()
+ * @sa krb5_storage_from_data()
+ */
+
 krb5_storage * KRB5_LIB_FUNCTION
 krb5_storage_emem(void)
 {
@@ -142,6 +183,7 @@ krb5_storage_emem(void)
     sp->fetch = emem_fetch;
     sp->store = emem_store;
     sp->seek = emem_seek;
+    sp->trunc = emem_trunc;
     sp->free = emem_free;
     return sp;
 }