1 files changed, 92 insertions, 0 deletions
diff --git a/dlfcn/dlerror.h b/dlfcn/dlerror.h
new file mode 100644
index 0000000000..cb9a9cea4c
--- /dev/null
+++ b/dlfcn/dlerror.h
@@ -0,0 +1,92 @@
+/* Memory management for dlerror messages.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _DLERROR_H
+#define _DLERROR_H
+
+#include <dlfcn.h>
+#include <ldsodefs.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+/* Source of the errstring member in struct dl_action_result, for
+   finding the right deallocation routine.  */
+enum dl_action_result_errstring_source
+  {
+   dl_action_result_errstring_constant, /* String literal, no deallocation.  */
+   dl_action_result_errstring_rtld, /* libc in the primary namespace.  */
+   dl_action_result_errstring_local, /* libc in the current namespace.  */
+  };
+
+struct dl_action_result
+{
+  int errcode;
+  char errstring_source;
+  bool returned;
+  const char *objname;
+  char *errstring;
+};
+
+/* Used to free the errstring member of struct dl_action_result in the
+   dl_action_result_errstring_rtld case.  */
+static inline void
+dl_error_free (void *ptr)
+{
+#ifdef SHARED
+  /* In the shared case, ld.so may use a different malloc than this
+     namespace.  */
+  GLRO (dl_error_free (ptr));
+#else
+  /* Call the implementation directly.  It still has to check for
+     pointers which cannot be freed, so do not call free directly
+     here.  */
+  _dl_error_free (ptr);
+#endif
+}
+
+/* Deallocate RESULT->errstring, leaving *RESULT itself allocated.  */
+static inline void
+dl_action_result_errstring_free (struct dl_action_result *result)
+{
+  switch (result->errstring_source)
+    {
+    case dl_action_result_errstring_constant:
+      break;
+    case dl_action_result_errstring_rtld:
+      dl_error_free (result->errstring);
+      break;
+    case dl_action_result_errstring_local:
+      free (result->errstring);
+      break;
+    }
+}
+
+/* Stand-in for an error result object whose allocation failed.  No
+   precise message can be reported for this, but an error must still
+   be signaled.  */
+static struct dl_action_result *const dl_action_result_malloc_failed
+  __attribute__ ((unused)) = (struct dl_action_result *) (intptr_t) -1;
+
+/* Thread-local variable for storing dlfcn failures for subsequent
+   reporting via dlerror.  */
+extern __thread struct dl_action_result *__libc_dlerror_result
+  attribute_tls_model_ie;
+void __libc_dlerror_result_free (void) attribute_hidden;
+
+#endif /* _DLERROR_H */