Make free functions behave more like free(3)

src/event.c

@@ -106,6 +106,10 @@ void event_init(pblog_Event *event) { memset(event, 0, sizeof(*event)); }
 
 void event_free(pblog_Event *event) {
   int i = 0;
+
+  if (event == NULL)
+    return;
+
   for (i = 0; i < event->data_count; ++i) {
     free(event->data[i].key.arg);
     event->data[i].key.arg = NULL;

src/nvram.c

@@ -80,6 +80,9 @@ static const struct nvram_entry *find_key(const struct nvram_entry *entries,
 }
 
 void nvram_entry_free(struct nvram_entry *entry) {
+  if (entry == NULL)
+    return;
+
   free(entry->key);
   free(entry->data);
 }
@@ -127,6 +130,10 @@ static int nvram_enumerate(struct nvram *nvram, struct nvram_entry **entries) {
 
 void nvram_list_free(struct nvram_entry **entries) {
   struct nvram_entry *entry;
+
+  if (*entries == NULL)
+    return;
+
   for (entry = *entries; entry && entry->key != NULL; entry++) {
     nvram_entry_free(entry);
   }

src/pblog.c

@@ -317,7 +317,12 @@ int pblog_init(struct pblog *pblog, int allow_clear_on_add,
 }
 
 void pblog_free(struct pblog *pblog) {
-  struct pblog_metadata *meta = pblog->priv;
+  struct pblog_metadata *meta;
+
+  if (pblog == NULL)
+    return;
+
+  meta = pblog->priv;
   record_intf_free(meta->mem_ri);
   free(meta->mem_ri);
   pblog_mem_ops.priv = NULL;

src/record.c

@@ -459,7 +459,12 @@ int record_intf_init(record_intf *ri, const struct record_region *regions,
 }
 
 void record_intf_free(record_intf *ri) {
-  struct log_metadata *meta = ri->priv;
+  struct log_metadata *meta;
+
+  if (ri == NULL)
+    return;
+
+  meta = ri->priv;
   free(meta->regions);
   free(meta);
 }