Add dixCreatePrivateKey API

Keys need to persist through server reset so that the private system
can be cleaned up in dixResetPrivates. In particular, this means that
keys cannot live in objects freed at reset time. This API provides
suitable object lifetime by having the privates code free the key in
the reset path.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jamey Sharp <jamey@minilop.net>

dix/privates.c

@@ -229,12 +229,37 @@ dixRegisterPrivateKey(DevPrivateKey key, DevPrivateType type, unsigned size)
     key->size = size;
     key->initialized = TRUE;
     key->type = type;
+    key->allocated = FALSE;
     key->next = keys[type].key;
     keys[type].key = key;
 
     return TRUE;
 }
 
+/*
+ * Allocate a new private key.
+ *
+ * This manages the storage of the key object itself, freeing it when the
+ * privates system is restarted at server reset time. All other keys
+ * are expected to be statically allocated as the privates must be
+ * reset after all objects have been freed
+ */
+DevPrivateKey
+dixCreatePrivateKey(DevPrivateType type, unsigned size)
+{
+    DevPrivateKey	key;
+
+    key = calloc(sizeof (DevPrivateKeyRec), 1);
+    if (!key)
+	return NULL;
+    if (!dixRegisterPrivateKey(key, type, size)) {
+	free(key);
+	return NULL;
+    }
+    key->allocated = TRUE;
+    return key;
+}
+
 /*
  * Initialize privates by zeroing them
  */
@@ -444,13 +469,16 @@ dixResetPrivates(void)
     DevPrivateType	t;
 
     for (t = PRIVATE_XSELINUX; t < PRIVATE_LAST; t++) {
-	DevPrivateKey	key;
+	DevPrivateKey	key, next;
 
-	for (key = keys[t].key; key; key = key->next) {
+	for (key = keys[t].key; key; key = next) {
+	    next = key->next;
 	    key->offset = 0;
 	    key->initialized = FALSE;
 	    key->size = 0;
 	    key->type = 0;
+	    if (key->allocated)
+		free(key);
 	}
 	if (keys[t].created) {
 	    ErrorF("%d %ss still allocated at reset\n",

include/privates.h

@@ -60,6 +60,7 @@ typedef struct _DevPrivateKeyRec {
     int			offset;
     int			size;
     Bool		initialized;
+    Bool		allocated;
     DevPrivateType	type;
     struct _DevPrivateKeyRec	*next;
 } DevPrivateKeyRec, *DevPrivateKey;
@@ -98,6 +99,17 @@ dixPrivateKeyRegistered(DevPrivateKey key)
     return key->initialized;
 }
 
+/*
+ * Allocate a new private key.
+ *
+ * This manages the storage of the key object itself, freeing it when the
+ * privates system is restarted at server reset time. All other keys
+ * are expected to be statically allocated as the privates must be
+ * reset after all objects have been freed
+ */
+extern _X_EXPORT DevPrivateKey
+dixCreatePrivateKey(DevPrivateType type, unsigned size);
+
 /*
  * Get the address of the private storage.
  *