tools: ynl: replace print with NlError

Instead of dumping the error on the stdout, make the callee and
opportunity to decide what to do with it. This is mostly for the
ethtool testing.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/net/ynl/lib/ynl.py b/tools/net/ynl/lib/ynl.py
index 8778994d40c03a0be79556040a237dd28da6a79a..373c0edb5f83d994ee0056127e0e0df331d3adc5 100644 (file)
--- a/tools/net/ynl/lib/ynl.py
+++ b/tools/net/ynl/lib/ynl.py
@@ -67,6 +67,14 @@ class Netlink:
     NLMSGERR_ATTR_MISS_NEST = 6
 
 
+class NlError(Exception):
+  def __init__(self, nl_msg):
+    self.nl_msg = nl_msg
+
+  def __str__(self):
+    return f"Netlink error: {os.strerror(-self.nl_msg.error)}\n{self.nl_msg}"
+
+
 class NlAttr:
     type_formats = { 'u8' : ('B', 1), 's8' : ('b', 1),
                      'u16': ('H', 2), 's16': ('h', 2),
@@ -551,9 +559,7 @@ class YnlFamily(SpecFamily):
                     self._decode_extack(msg, op.attr_set, nl_msg.extack)
 
                 if nl_msg.error:
-                    print("Netlink error:", os.strerror(-nl_msg.error))
-                    print(nl_msg)
-                    return
+                    raise NlError(nl_msg)
                 if nl_msg.done:
                     if nl_msg.extack:
                         print("Netlink warning:")