Fix memory leaks in plugins (#13028)

* Fix leak in client_context_dump — free results array after
  iterating context names in CB_context_dump.

* Fix leak in s3_auth ConfigCache — add destructor to delete
  all cached S3Config pointers on shutdown.

* Fix leak in stale_response — free log_info.filename in
  ConfigInfo destructor when strdup()d.

Author: bryancall

example/plugins/c-api/client_context_dump/client_context_dump.cc

@@ -163,6 +163,7 @@ CB_context_dump(TSCont, TSEvent, void *edata)
       for (int i = 0; i < count; i += 2) {
         dump_context(results[i], results[i + 1]);
       }
+      free(results);
     }
   }
   TSTextLogObjectFlush(context_dump_log);

plugins/experimental/stale_response/stale_response.h

@@ -23,6 +23,8 @@
 
 #pragma once
 
+#include <cstdlib>
+
 #include "ts/apidefs.h"
 #include "ts_wrap.h"
 #include "ts/ts.h"
@@ -63,6 +65,9 @@ struct ConfigInfo {
     if (this->body_data_mutex) {
       TSMutexDestroy(this->body_data_mutex);
     }
+    if (this->log_info.filename != PLUGIN_TAG) {
+      free(const_cast<char *>(this->log_info.filename));
+    }
   }
   UintBodyMap *body_data = nullptr;
   TSMutex      body_data_mutex;

plugins/origin_server_auth/origin_server_auth.cc

@@ -154,6 +154,8 @@ class S3Config;
 class ConfigCache
 {
 public:
+  ~ConfigCache();
+
   S3Config *get(const char *fname);
 
 private:
@@ -601,6 +603,13 @@ class S3Config
   int       _invalid_file_count  = 0;
 };
 
+ConfigCache::~ConfigCache()
+{
+  for (auto &[key, data] : _cache) {
+    delete data.config.load();
+  }
+}
+
 bool
 S3Config::parse_config(const std::string &config_fname)
 {