Fix error detection in virStorageBackendISCSIGetHostNumber

In the unlikely case the iSCSI session path exists, but does not
contain an entry starting with "target", we would silently use
an initialized value.

Rewrite the function to correctly report errors.

src/storage/storage_backend_iscsi.c

@@ -91,7 +91,7 @@ static int
 virStorageBackendISCSIGetHostNumber(const char *sysfs_path,
                                     uint32_t *host)
 {
-    int retval = 0;
+    int ret = -1;
     DIR *sysdir = NULL;
     struct dirent *dirent = NULL;
     int direrr;
@@ -100,27 +100,32 @@ virStorageBackendISCSIGetHostNumber(const char *sysfs_path,
 
     virFileWaitForDevices();
 
-    if (virDirOpen(&sysdir, sysfs_path) < 0) {
-        retval = -1;
-        goto out;
-    }
+    if (virDirOpen(&sysdir, sysfs_path) < 0)
+        goto cleanup;
 
     while ((direrr = virDirRead(sysdir, &dirent, sysfs_path)) > 0) {
         if (STRPREFIX(dirent->d_name, "target")) {
-            if (sscanf(dirent->d_name,
-                       "target%u:", host) != 1) {
-                VIR_DEBUG("Failed to parse target '%s'", dirent->d_name);
-                retval = -1;
-                break;
+            if (sscanf(dirent->d_name, "target%u:", host) == 1) {
+                ret = 0;
+                goto cleanup;
+            } else {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               _("Failed to parse target '%s'"), dirent->d_name);
+                goto cleanup;
             }
         }
     }
-    if (direrr < 0)
-        retval = -1;
 
+    if (direrr == 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Failed to get host number for iSCSI session "
+                         "with path '%s'"), sysfs_path);
+        goto cleanup;
+    }
+
+ cleanup:
     VIR_DIR_CLOSE(sysdir);
- out:
-    return retval;
+    return ret;
 }
 
 static int
@@ -135,13 +140,8 @@ virStorageBackendISCSIFindLUs(virStoragePoolObjPtr pool,
                     "/sys/class/iscsi_session/session%s/device", session) < 0)
         goto cleanup;
 
-    if (virStorageBackendISCSIGetHostNumber(sysfs_path, &host) < 0) {
-        virReportSystemError(errno,
-                             _("Failed to get host number for iSCSI session "
-                               "with path '%s'"),
-                             sysfs_path);
+    if (virStorageBackendISCSIGetHostNumber(sysfs_path, &host) < 0)
         goto cleanup;
-    }
 
     if (virStorageBackendSCSIFindLUs(pool, host) < 0)
         goto cleanup;