mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-25 20:21:07 +00:00
83 lines
2.4 KiB
C
83 lines
2.4 KiB
C
/* Early memory allocation for the dynamic loader. Generic version.
|
|
Copyright (C) 2022-2023 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/>. */
|
|
|
|
/* Mark symbols hidden in static PIE for early self relocation to work. */
|
|
#if BUILD_PIE_DEFAULT
|
|
# pragma GCC visibility push(hidden)
|
|
#endif
|
|
#include <startup.h>
|
|
|
|
#include <ldsodefs.h>
|
|
#include <stddef.h>
|
|
#include <string.h>
|
|
#include <sysdep.h>
|
|
#include <unistd.h>
|
|
|
|
#include <brk_call.h>
|
|
#include <mmap_call.h>
|
|
|
|
/* Defined in brk.c. */
|
|
extern void *__curbrk;
|
|
|
|
void *
|
|
_dl_early_allocate (size_t size)
|
|
{
|
|
void *result;
|
|
|
|
if (__curbrk != NULL)
|
|
/* If the break has been initialized, brk must have run before,
|
|
so just call it once more. */
|
|
{
|
|
result = __sbrk (size);
|
|
if (result == (void *) -1)
|
|
result = NULL;
|
|
}
|
|
else
|
|
{
|
|
/* If brk has not been invoked, there is no need to update
|
|
__curbrk. The first call to brk will take care of that. */
|
|
void *previous = __brk_call (0);
|
|
result = __brk_call (previous + size);
|
|
if (result == previous)
|
|
result = NULL;
|
|
else
|
|
result = previous;
|
|
}
|
|
|
|
/* If brk fails, fall back to mmap. This can happen due to
|
|
unfortunate ASLR layout decisions and kernel bugs, particularly
|
|
for static PIE. */
|
|
if (result == NULL)
|
|
{
|
|
long int ret;
|
|
int prot = PROT_READ | PROT_WRITE;
|
|
int flags = MAP_PRIVATE | MAP_ANONYMOUS;
|
|
#ifdef __NR_mmap2
|
|
ret = MMAP_CALL_INTERNAL (mmap2, 0, size, prot, flags, -1, 0);
|
|
#else
|
|
ret = MMAP_CALL_INTERNAL (mmap, 0, size, prot, flags, -1, 0);
|
|
#endif
|
|
if (INTERNAL_SYSCALL_ERROR_P (ret))
|
|
result = NULL;
|
|
else
|
|
result = (void *) ret;
|
|
}
|
|
|
|
return result;
|
|
}
|