[libvirt] [PATCH] virsh: Report errors if arguments of the schedinfo command are incorrect

[Peter Krempa]

Libvirt's helper API's when called directly don't raise the error so
that virsh remembers it. Subsequent calls to libvirt API's might reset
the error.

In case of schedinfo virDomainFree() in the cleanup section resets the
error when virTypedParameterAssignFromStr() fails.

This patch adds function vshSaveLibvirtError() that can be called after
calling libvirt helper APIs to ensure the error is remembered.
---
 tools/virsh-domain.c | 8 ++++++--
 tools/virsh.c        | 9 +++++++++
 tools/virsh.h        | 1 +
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index 73ebba9..1f7aff7 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -3512,8 +3512,10 @@ cmdSchedInfoUpdate(vshControl *ctl, const vshCmd *cmd,
             if (virTypedParameterAssign(&(params[nparams++]),
                                         param->field,
                                         param->type,
-                                        val) < 0)
+                                        val) < 0) {
+                vshSaveLibvirtError();
                 goto cleanup;
+            }

             continue;
         }
@@ -3523,8 +3525,10 @@ cmdSchedInfoUpdate(vshControl *ctl, const vshCmd *cmd,
             if (virTypedParameterAssignFromStr(&(params[nparams++]),
                                                param->field,
                                                param->type,
-                                               set_val) < 0)
+                                               set_val) < 0) {
+                vshSaveLibvirtError();
                 goto cleanup;
+            }

             continue;
         }
diff --git a/tools/virsh.c b/tools/virsh.c
index dea3f82..322f778 100644
--- a/tools/virsh.c
+++ b/tools/virsh.c
@@ -240,6 +240,15 @@ virshErrorHandler(void *unused ATTRIBUTE_UNUSED, virErrorPtr error)
         virDefaultErrorFunc(error);
 }

+/* Store a libvirt error that is from a helper API that doesn't raise errors
+ * so it doesn't get overwritten */
+void
+vshSaveLibvirtError(void)
+{
+    virFreeError(last_error);
+    last_error = virSaveLastError();
+}
+
 /*
  * Reset libvirt error on graceful fallback paths
  */
diff --git a/tools/virsh.h b/tools/virsh.h
index ba44f42..6913ed1 100644
--- a/tools/virsh.h
+++ b/tools/virsh.h
@@ -346,6 +346,7 @@ struct _vshCtrlData {
 extern virErrorPtr last_error;
 void vshReportError(vshControl *ctl);
 void vshResetLibvirtError(void);
+void vshSaveLibvirtError(void);

 /* allocation wrappers */
 void *_vshMalloc(vshControl *ctl, size_t sz, const char *filename, int line);
-- 
1.8.0