glibc/include/rtld-malloc.h

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/* Redirection of malloc inside the dynamic linker.
Copyright (C) 2020 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/>. */
/* The dynamic linker needs to use its own minimal malloc before libc
has been relocated, and the libc malloc afterwards. The active
malloc implementation is reached via the __rtld_* function pointers
declared below. They are initialized to the minimal malloc by
__rtld_malloc_init_stubs, and set to the final implementation by
__rtld_malloc_init_real. */
#ifndef _RTLD_MALLOC_H
#define _RTLD_MALLOC_H
#if IS_IN (rtld)
extern __typeof (calloc) *__rtld_calloc attribute_hidden;
extern __typeof (free) *__rtld_free attribute_hidden;
extern __typeof (malloc) *__rtld_malloc attribute_hidden;
extern __typeof (realloc) *__rtld_realloc attribute_hidden;
/* Wrapper functions which call through the function pointers above.
Note that it is not supported to take the address of those
functions. Instead the function pointers must be used
directly. */
__extern_inline void *
calloc (size_t a, size_t b)
{
return __rtld_calloc (a, b);
}
__extern_inline void
free (void *ptr)
{
__rtld_free (ptr);
}
__extern_inline void *
malloc (size_t size)
{
return __rtld_malloc (size);
}
__extern_inline void *
realloc (void *ptr, size_t size)
{
return __rtld_realloc (ptr, size);
}
/* Called after the first self-relocation to activate the minimal malloc
implementation. */
void __rtld_malloc_init_stubs (void) attribute_hidden;
/* Called shortly before the final self-relocation (when RELRO
variables are still writable) to activate the real malloc
implementation. MAIN_MAP is the link map of the executable. */
struct link_map;
void __rtld_malloc_init_real (struct link_map *main_map) attribute_hidden;
#else /* !IS_IN (rtld) */
/* This allows static/non-rtld builds to get a pointer to the
functions, in the same way that is required inside rtld. */
# define __rtld_calloc (&calloc)
# define __rtld_free (&free)
# define __rtld_malloc (&malloc)
# define __rtld_realloc (&realloc)
#endif /* !IS_IN (rtld) */
#endif /* _RTLD_MALLOC_H */