[Libvirt-cim] [PATCH V3 06/11] DevicePool, reimplement get_diskpool_config with libvirt

[Wenchao Xia]

  Original implemetion may return pools with NULL name if
some pool disappear between two libvirt pool API call. And
caller of this function consider number = 0 as error only
but it original return negative value when error before.
This patch fix it.

V2:
  Use for instead of while in clean up.
  Treat zero pool returned from libvirt as normal instead of error.
  Rebased.

v3:
  fix wrong i++ in for while.

Signed-off-by: Wenchao Xia <xiawenc at linux.vnet.ibm.com>
---
 src/Virt_DevicePool.c |   39 +++++++++++++++++++++++++++++----------
 1 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/src/Virt_DevicePool.c b/src/Virt_DevicePool.c
index 79dc108..769de63 100644
--- a/src/Virt_DevicePool.c
+++ b/src/Virt_DevicePool.c
@@ -117,52 +117,71 @@ int get_disk_pool(virStoragePoolPtr poolptr, struct virt_pool **pool)
         return ret;
 }
 
+/* This function returns the real number of pools, no negative value should be
+   returned, if error happens it returns zero, otherwise return at least 1. */
 static int get_diskpool_config(virConnectPtr conn,
                                struct tmp_disk_pool **_pools)
 {
-        int count = 0;
+        int count = 0, realcount = 0;
         int i;
         char ** names = NULL;
         struct tmp_disk_pool *pools = NULL;
+        int have_err = 0;
 
         count = virConnectNumOfStoragePools(conn);
-        if (count <= 0)
+        if (count < 0) {
+                have_err = 1;
                 goto out;
+        } else if (count == 0) {
+                goto out;
+        }
 
         names = calloc(count, sizeof(char *));
         if (names == NULL) {
                 CU_DEBUG("Failed to alloc space for %i pool names", count);
                 count = 0;
+                have_err = 1;
                 goto out;
         }
 
-        if (virConnectListStoragePools(conn, names, count) == -1) {
+        realcount = virConnectListStoragePools(conn, names, count);
+        if (realcount == -1) {
                 CU_DEBUG("Failed to get storage pools");
-                count = 0;
+                realcount = 0;
+                have_err = 1;
+                goto out;
+        }
+        if (realcount == 0) {
+                CU_DEBUG("zero pools got, but prelist is %d.", count);
                 goto out;
         }
 
-        pools = calloc(count, sizeof(*pools));
+        pools = calloc(realcount, sizeof(*pools));
         if (pools == NULL) {
-                CU_DEBUG("Failed to alloc space for %i pool structs", count);
+                CU_DEBUG("Failed to alloc space for %i pool structs", realcount);
+                realcount = 0;
+                have_err = 1;
                 goto out;
         }
 
-        for (i = 0; i < count; i++) {
+        for (i = 0; i < realcount; i++) {
                 pools[i].tag = strdup(names[i]);
                 pools[i].primordial = false;
         }
 
  out:
-        for (i = 0; i < count; i++)
+        for (i = 0; i < count; i++) {
                 free(names[i]);
+        }
         free(names);
 
-        get_disk_parent(&pools, &count);
+        if (have_err == 0) {
+                get_disk_parent(&pools, &realcount);
+        }
 
         *_pools = pools;
 
-        return count;
+        return realcount;
 }
 
 static bool diskpool_set_capacity(virConnectPtr conn,
-- 
1.7.1