From 57dbc55cd3e239ab0ce5bdd62cf309e27fe52a1a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Mon, 5 Sep 2016 12:15:26 +0200
Subject: [PATCH] libxl: do not assume Dom0 backend while getting nic info
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Fill backend_domid field based on backend path.

[ Correspoding xen.git#master commit is 7539772a65b0 -iwj ]

Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
(cherry picked from commit 317eb71bc3b0830338601fb14d1f49546a1c1e35)
---
 tools/libxl/libxl.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 45d202a9c2..18e9d4d553 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -3485,6 +3485,18 @@ static int libxl__device_nic_from_xenstore(libxl__gc *gc,
     else
         nic->devid = 0;
 
+    rc = libxl__xs_read_checked(gc, XBT_NULL,
+                                GCSPRINTF("%s/backend", libxl_path), &tmp);
+    if (rc) goto out;
+
+    if (!tmp) {
+        LOG(ERROR, "nic %s does not exist (no backend path)", libxl_path);
+        rc = ERROR_FAIL;
+        goto out;
+    }
+    rc = libxl__backendpath_parse_domid(gc, tmp, &nic->backend_domid);
+    if (rc) goto out;
+
     /* nic->mtu = */
 
     tmp = READ_LIBXLDEV(gc, "mac");