driver: make NULL as valid parent ID

Signed-off-by: NLiFeng <lifeng68@huawei.com>

src/image/oci/storage/layer_store/graphdriver/devmapper/driver_devmapper.c

@@ -48,7 +48,7 @@ static int do_create(const char *id, const char *parent, const struct driver_cre
 int devmapper_create_rw(const char *id, const char *parent, const struct graphdriver *driver,
                         const struct driver_create_opts *create_opts)
 {
-    if (id == NULL || parent == NULL || driver == NULL || create_opts == NULL) {
+    if (id == NULL || driver == NULL || create_opts == NULL) {
         return -1;
     }
 
@@ -59,7 +59,7 @@ int devmapper_create_rw(const char *id, const char *parent, const struct graphdr
 int devmapper_create_ro(const char *id, const char *parent, const struct graphdriver *driver,
                         const struct driver_create_opts *create_opts)
 {
-    if (id == NULL || parent == NULL || driver == NULL || create_opts == NULL) {
+    if (id == NULL || driver == NULL || create_opts == NULL) {
         return -1;
     }
 

src/image/oci/storage/layer_store/graphdriver/driver.c

@@ -110,7 +110,7 @@ int graphdriver_create_rw(const char *id, const char *parent, struct driver_crea
         return -1;
     }
 
-    if (id == NULL || parent == NULL || create_opts == NULL) {
+    if (id == NULL || create_opts == NULL) {
         ERROR("Invalid input arguments for driver create");
         return -1;
     }
@@ -125,7 +125,7 @@ int graphdriver_create_ro(const char *id, const char *parent, const struct drive
         return -1;
     }
 
-    if (id == NULL || parent == NULL || create_opts == NULL) {
+    if (id == NULL || create_opts == NULL) {
         ERROR("Invalid input arguments for driver create");
         return -1;
     }
@@ -296,7 +296,7 @@ int graphdriver_try_repair_lowers(const char *id, const char *parent)
         return -1;
     }
 
-    if (id == NULL || parent == NULL) {
+    if (id == NULL) {
         ERROR("Invalid input arguments for driver repair lower");
         return -1;
     }

src/image/oci/storage/layer_store/graphdriver/overlay2/driver_overlay2.c

@@ -339,7 +339,7 @@ static int check_parent_valid(const char *parent, const struct graphdriver *driv
     int ret = 0;
     char *parent_dir = NULL;
 
-    if (strcmp(parent, "") != 0) {
+    if (parent != NULL) {
         parent_dir = util_path_join(driver->home, parent);
         if (parent_dir == NULL) {
             ERROR("Failed to join layer dir:%s", parent);
@@ -677,7 +677,7 @@ static int mk_sub_directorys(const char *id, const char *parent, const char *lay
         goto out;
     }
 
-    if (strcmp(parent, "") == 0) {
+    if (parent == NULL) {
         if (mk_empty_directory(layer_dir) != 0) {
             ret = -1;
             goto out;
@@ -822,7 +822,7 @@ int overlay2_create_rw(const char *id, const char *parent, const struct graphdri
 {
     int ret = 0;
 
-    if (id == NULL || parent == NULL || driver == NULL || create_opts == NULL) {
+    if (id == NULL || driver == NULL || create_opts == NULL) {
         return -1;
     }
 
@@ -848,7 +848,7 @@ int overlay2_create_ro(const char *id, const char *parent, const struct graphdri
 {
     int ret = 0;
 
-    if (id == NULL || parent == NULL || driver == NULL || create_opts == NULL) {
+    if (id == NULL || driver == NULL || create_opts == NULL) {
         return -1;
     }
 
@@ -1783,7 +1783,7 @@ int overlay2_repair_lowers(const char *id, const char *parent, const struct grap
     char **lowers_arr = NULL;
     size_t lowers_size = 0;
 
-    if (id == NULL || driver == NULL || parent == NULL) {
+    if (id == NULL || driver == NULL) {
         return -1;
     }
 
@@ -1810,7 +1810,7 @@ int overlay2_repair_lowers(const char *id, const char *parent, const struct grap
         }
     }
 
-    if (strcmp(parent, "") == 0) {
+    if (parent == NULL) {
         if (mk_empty_directory(layer_dir) != 0) {
             ret = -1;
             goto out;

src/image/oci/storage/storage.c

@@ -96,7 +96,7 @@ int storage_layer_create(const char *layer_id, const char *parent_id, bool write
     struct io_read_wrapper reader = { 0 };
     struct layer_opts *opts = NULL;
 
-    if (layer_id == NULL || parent_id == NULL || layer_data_path == NULL) {
+    if (layer_id == NULL || layer_data_path == NULL) {
         ERROR("Invalid arguments for put ro layer");
         ret = -1;
         goto out;
@@ -197,7 +197,7 @@ int storage_img_create(const char *id, const char *parent_id, const char *metada
     int ret = 0;
     char *image_id = NULL;
 
-    if (id == NULL || parent_id == NULL || metadata == NULL || opts == NULL) {
+    if (id == NULL || metadata == NULL || opts == NULL) {
         ERROR("Invalid arguments for image create");
         ret = -1;
         goto out;