esx: Use MD5 sum of mount path as storage pool UUID

With the previous storage pool UUID source not all storage pools
had a proper UUID, especially GSX storage pools. The mount path
is unique per host and cannot change during the lifetime of the
datastore. Therefore, it's MD5 sum can be used as UUID.

Use gnulib's crypto/md5 module to generate the MD5 sum.

diff --git a/bootstrap.conf b/bootstrap.conf
index 5af77a74887d42405555951ca37a44dbf6d094b5..ca31a6e26739781d84f4f81a76dd13951d5d7d23 100644 (file)
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -26,6 +26,7 @@ canonicalize-lgpl
 close
 connect
 count-one-bits
+crypto/md5
 dirname-lgpl
 fcntl-h
 getaddrinfo

diff --git a/src/esx/esx_storage_driver.c b/src/esx/esx_storage_driver.c
index 4fcc4af745c379c35ea81bc8dce6dcdae30aa763..26747bbfd2452c5b57474ede29d2dfb3b6e42337 100644 (file)
--- a/src/esx/esx_storage_driver.c
+++ b/src/esx/esx_storage_driver.c
@@ -24,6 +24,8 @@
 
 #include <config.h>
 
+#include "md5.h"
+#include "verify.h"
 #include "internal.h"
 #include "util.h"
 #include "memory.h"
@@ -38,6 +40,12 @@
 
 #define VIR_FROM_THIS VIR_FROM_ESX
 
+/*
+ * The UUID of a storage pool is the MD5 sum of it's mount path. Therefore,
+ * verify that UUID and MD5 sum match in size, because we rely on that.
+ */
+verify(MD5_DIGEST_SIZE == VIR_UUID_BUFLEN);
+
 
 
 static virDrvOpenStatus
@@ -196,10 +204,7 @@ esxStoragePoolLookupByName(virConnectPtr conn, const char *name)
     esxPrivate *priv = conn->storagePrivateData;
     esxVI_ObjectContent *datastore = NULL;
     esxVI_DatastoreHostMount *hostMount = NULL;
-    char *suffix = NULL;
-    int suffixLength;
-    char uuid_string[VIR_UUID_STRING_BUFLEN] = "00000000-00000000-0000-000000000000";
-    unsigned char uuid[VIR_UUID_BUFLEN];
+    unsigned char md5[MD5_DIGEST_SIZE]; /* MD5_DIGEST_SIZE = VIR_UUID_BUFLEN = 16 */
     virStoragePoolPtr pool = NULL;
 
     if (esxVI_EnsureSession(priv->primary) < 0) {
@@ -212,53 +217,22 @@ esxStoragePoolLookupByName(virConnectPtr conn, const char *name)
     }
 
     /*
-     * Datastores don't have a UUID. We can use the 'host.mountInfo.path'
-     * property as source for a "UUID" on ESX, because the property value has
-     * this format:
-     *
-     *   host.mountInfo.path = /vmfs/volumes/4b0beca7-7fd401f3-1d7f-000ae484a6a3
-     *   host.mountInfo.path = /vmfs/volumes/b24b7a78-9d82b4f5    (short format)
-     *
-     * The 'host.mountInfo.path' property comes in two forms, with a complete
-     * "UUID" and a short "UUID".
+     * Datastores don't have a UUID, but we can use the 'host.mountInfo.path'
+     * property as source for a UUID. The mount path is unique per host and
+     * cannot change during the lifetime of the datastore.
      *
-     * But this trailing "UUID" is not guaranteed to be there. On the other
-     * hand we already rely on another implementation detail of the ESX server:
-     * The object name of virtual machine contains an integer, we use that as
-     * domain ID.
+     * The MD5 sum of the mount path can be used as UUID, assuming MD5 is
+     * considered to be collision-free enough for this use case.
      */
     if (esxVI_LookupDatastoreHostMount(priv->primary, datastore->obj,
                                        &hostMount) < 0) {
         goto cleanup;
     }
 
-    if ((suffix = STRSKIP(hostMount->mountInfo->path, "/vmfs/volumes/")) != NULL) {
-        suffixLength = strlen(suffix);
-
-        if ((suffixLength == 35 && /* = strlen("4b0beca7-7fd401f3-1d7f-000ae484a6a3") */
-             suffix[8] == '-' && suffix[17] == '-' && suffix[22] == '-') ||
-            (suffixLength == 17 && /* = strlen("b24b7a78-9d82b4f5") */
-             suffix[8] == '-')) {
-            /*
-             * Intentionally use memcpy here, because we want to be able to
-             * replace a prefix of the initial Zero-UUID. virStrncpy would
-             * null-terminate the string in an unwanted place.
-             */
-            memcpy(uuid_string, suffix, suffixLength);
-        } else {
-            VIR_WARN("Datastore host mount path suffix '%s' has unexpected "
-                     "format, cannot deduce a UUID from it", suffix);
-        }
-    }
-
-    if (virUUIDParse(uuid_string, uuid) < 0) {
-        ESX_ERROR(VIR_ERR_INTERNAL_ERROR,
-                  _("Could not parse UUID from string '%s'"),
-                  uuid_string);
-        goto cleanup;
-    }
+    md5_buffer(hostMount->mountInfo->path,
+               strlen(hostMount->mountInfo->path), md5);
 
-    pool = virGetStoragePool(conn, name, uuid);
+    pool = virGetStoragePool(conn, name, md5);
 
   cleanup:
     esxVI_ObjectContent_Free(&datastore);
@@ -274,9 +248,11 @@ esxStoragePoolLookupByUUID(virConnectPtr conn, const unsigned char *uuid)
 {
     esxPrivate *priv = conn->storagePrivateData;
     esxVI_String *propertyNameList = NULL;
+    esxVI_ObjectContent *datastoreList = NULL;
     esxVI_ObjectContent *datastore = NULL;
+    esxVI_DatastoreHostMount *hostMount = NULL;
+    unsigned char md5[MD5_DIGEST_SIZE]; /* MD5_DIGEST_SIZE = VIR_UUID_BUFLEN = 16 */
     char uuid_string[VIR_UUID_STRING_BUFLEN] = "";
-    char *absolutePath = NULL;
     char *name = NULL;
     virStoragePoolPtr pool = NULL;
 
@@ -284,48 +260,26 @@ esxStoragePoolLookupByUUID(virConnectPtr conn, const unsigned char *uuid)
         return NULL;
     }
 
-    /*
-     * Convert UUID to 'host.mountInfo.path' form by stripping the second '-':
-     *
-     * <---- 14 ----><-------- 22 -------->    <---- 13 ---><-------- 22 -------->
-     * 4b0beca7-7fd4-01f3-1d7f-000ae484a6a3 -> 4b0beca7-7fd401f3-1d7f-000ae484a6a3
-     */
-    virUUIDFormat(uuid, uuid_string);
-    memmove(uuid_string + 13, uuid_string + 14, 22 + 1);
-
-    if (virAsprintf(&absolutePath, "/vmfs/volumes/%s", uuid_string) < 0) {
-        virReportOOMError();
-        goto cleanup;
-    }
-
     if (esxVI_String_AppendValueToList(&propertyNameList, "summary.name") < 0 ||
-        esxVI_LookupDatastoreByAbsolutePath(priv->primary, absolutePath,
-                                            propertyNameList, &datastore,
-                                            esxVI_Occurrence_OptionalItem) < 0) {
+        esxVI_LookupDatastoreList(priv->primary, propertyNameList,
+                                  &datastoreList) < 0) {
         goto cleanup;
     }
 
-    /*
-     * If the first try didn't succeed and the trailing 16 digits are zero then
-     * the "UUID" could be a short one. Strip the 16 zeros and try again:
-     *
-     * <------ 17 ----->                      <------ 17 ----->
-     * b24b7a78-9d82b4f5-0000-000000000000 -> b24b7a78-9d82b4f5
-     */
-    if (datastore == NULL && STREQ(uuid_string + 17, "-0000-000000000000")) {
-        uuid_string[17] = '\0';
-
-        VIR_FREE(absolutePath);
+    for (datastore = datastoreList; datastore != NULL;
+         datastore = datastore->_next) {
+        esxVI_DatastoreHostMount_Free(&hostMount);
 
-        if (virAsprintf(&absolutePath, "/vmfs/volumes/%s", uuid_string) < 0) {
-            virReportOOMError();
+        if (esxVI_LookupDatastoreHostMount(priv->primary, datastore->obj,
+                                           &hostMount) < 0) {
             goto cleanup;
         }
 
-        if (esxVI_LookupDatastoreByAbsolutePath(priv->primary, absolutePath,
-                                                propertyNameList, &datastore,
-                                                esxVI_Occurrence_RequiredItem) < 0) {
-            goto cleanup;
+        md5_buffer(hostMount->mountInfo->path,
+                   strlen(hostMount->mountInfo->path), md5);
+
+        if (memcmp(uuid, md5, VIR_UUID_BUFLEN) == 0) {
+            break;
         }
     }
 
@@ -347,9 +301,9 @@ esxStoragePoolLookupByUUID(virConnectPtr conn, const unsigned char *uuid)
     pool = virGetStoragePool(conn, name, uuid);
 
   cleanup:
-    VIR_FREE(absolutePath);
     esxVI_String_Free(&propertyNameList);
-    esxVI_ObjectContent_Free(&datastore);
+    esxVI_ObjectContent_Free(&datastoreList);
+    esxVI_DatastoreHostMount_Free(&hostMount);
 
     return pool;
 }