[libvirt] [PATCHv2 3/3] util: Produce friendlier error message to user

[Luyao Huang]

Commit 1c24cfe9 fix the problem in virNumaSetPagePoolSize,
this patch just like it and fix the issue in another function.

when user use freepages and specify a invalid node or page size,
will get error like this:

  # virsh freepages 0 1
  error: Failed to open file '/sys/devices/system/node/node0/hugepages/hugepages-1kB/free_hugepages':No such file or directory

Add two checks to catch this and therefore produce much more
friendlier error messages.

Signed-off-by: Luyao Huang <lhuang at redhat.com>
---
 src/util/virnuma.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/src/util/virnuma.c b/src/util/virnuma.c
index 815cbc1..cd000f9 100644
--- a/src/util/virnuma.c
+++ b/src/util/virnuma.c
@@ -553,6 +553,25 @@ virNumaGetHugePageInfo(int node,
                                        page_size, "nr_hugepages") < 0)
             goto cleanup;
 
+        if (!virFileExists(path)) {
+            if (node != -1) {
+                if (!virNumaNodeIsAvailable(node)) {
+                    virReportError(VIR_ERR_OPERATION_FAILED,
+                                   _("NUMA node %d is not available"),
+                                   node);
+                } else {
+                    virReportError(VIR_ERR_OPERATION_FAILED,
+                                   _("page size %u is not available on node %d"),
+                                   page_size, node);
+                }
+            } else {
+                virReportError(VIR_ERR_OPERATION_FAILED,
+                               _("page size %u is not available"),
+                               page_size);
+            }
+            goto cleanup;
+        }
+
         if (virFileReadAll(path, 1024, &buf) < 0)
             goto cleanup;
 
@@ -572,6 +591,25 @@ virNumaGetHugePageInfo(int node,
                                        page_size, "free_hugepages") < 0)
             goto cleanup;
 
+        if (!virFileExists(path)) {
+            if (node != -1) {
+                if (!virNumaNodeIsAvailable(node)) {
+                    virReportError(VIR_ERR_OPERATION_FAILED,
+                                   _("NUMA node %d is not available"),
+                                   node);
+                } else {
+                    virReportError(VIR_ERR_OPERATION_FAILED,
+                                   _("page size %u is not available on node %d"),
+                                   page_size, node);
+                }
+            } else {
+                virReportError(VIR_ERR_OPERATION_FAILED,
+                               _("page size %u is not available"),
+                               page_size);
+            }
+            goto cleanup;
+        }
+
         if (virFileReadAll(path, 1024, &buf) < 0)
             goto cleanup;
 
-- 
1.8.3.1