glibc/dlfcn/dlerror.h

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/* 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 */