[vty] Allow to create a buffer in a given context.

Stop using the global vty context for all allocations
and allow to embed the buffer into a given context, and
allocate sub buffers with the context of its parent.

openbsc/include/vty/buffer.h

@@ -28,7 +28,7 @@
 /* Create a new buffer.  Memory will be allocated in chunks of the given
    size.  If the argument is 0, the library will supply a reasonable
    default size suitable for buffering socket I/O. */
-struct buffer *buffer_new(size_t);
+struct buffer *buffer_new(void *ctx, size_t);
 
 /* Free all data in the buffer. */
 void buffer_reset(struct buffer *);

openbsc/src/vty/buffer.c

@@ -65,11 +65,11 @@ struct buffer_data {
 #define BUFFER_DATA_FREE(D) talloc_free((D))
 
 /* Make new buffer. */
-struct buffer *buffer_new(size_t size)
+struct buffer *buffer_new(void *ctx, size_t size)
 {
 	struct buffer *b;
 
-	b = talloc_zero(tall_vty_ctx, struct buffer);
+	b = talloc_zero(ctx, struct buffer);
 
 	if (size)
 		b->size = size;
@@ -138,7 +138,7 @@ static struct buffer_data *buffer_add(struct buffer *b)
 {
 	struct buffer_data *d;
 
-	d = _talloc_zero(tall_vty_ctx,
+	d = _talloc_zero(b,
 			 offsetof(struct buffer_data, data[b->size]),
 			 "buffer_add");
 	if (!d)

openbsc/src/vty/vty.c

@@ -51,7 +51,7 @@ struct vty *vty_new()
 	if (!new)
 		goto out;
 
-	new->obuf = buffer_new(0);	/* Use default buffer size. */
+	new->obuf = buffer_new(new, 0);	/* Use default buffer size. */
 	if (!new->obuf)
 		goto out_new;
 	new->buf = _talloc_zero(new, VTY_BUFSIZ, "vty_new->buf");

openbsc/src/vty_interface_layer3.c

@@ -58,7 +58,7 @@ static int dummy_config_write(struct vty *v)
 
 static struct buffer *argv_to_buffer(int argc, const char *argv[], int base)
 {
-	struct buffer *b = buffer_new(1024);
+	struct buffer *b = buffer_new(NULL, 1024);
 	int i;
 
 	if (!b)