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/* Check that _dl_find_object behavior matches up with gaps.
Copyright (C) 2025 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/>. */
#include <dlfcn.h>
#include <gnu/lib-names.h>
#include <link.h>
#include <stdbool.h>
#include <stdio.h>
#include <support/check.h>
#include <support/xdlfcn.h>
#include <support/xunistd.h>
#include <sys/mman.h>
#include <unistd.h>
static int
do_test (void)
{
struct link_map *l = xdlopen (LD_SO, RTLD_NOW);
if (!l->l_contiguous)
{
puts ("info: ld.so link map is not contiguous");
/* Try to find holes by probing with mmap. */
int pagesize = getpagesize ();
bool gap_found = false;
ElfW(Addr) addr = l->l_map_start;
TEST_COMPARE (addr % pagesize, 0);
while (addr < l->l_map_end)
{
void *expected = (void *) addr;
void *ptr = xmmap (expected, 1, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1);
struct dl_find_object dlfo;
int dlfo_ret = _dl_find_object (expected, &dlfo);
if (ptr == expected)
{
if (dlfo_ret < 0)
{
TEST_COMPARE (dlfo_ret, -1);
printf ("info: hole without mapping data found at %p\n", ptr);
}
else
FAIL ("object \"%s\" found in gap at %p",
dlfo.dlfo_link_map->l_name, ptr);
gap_found = true;
}
else if (dlfo_ret == 0)
{
if ((void *) dlfo.dlfo_link_map != (void *) l)
{
printf ("info: object \"%s\" found at %p\n",
dlfo.dlfo_link_map->l_name, ptr);
gap_found = true;
}
}
else
TEST_COMPARE (dlfo_ret, -1);
xmunmap (ptr, 1);
addr += pagesize;
}
if (!gap_found)
FAIL ("no ld.so gap found");
}
else
{
puts ("info: ld.so link map is contiguous");
/* Assert that ld.so is truly contiguous in memory. */
volatile long int *p = (volatile long int *) l->l_map_start;
volatile long int *end = (volatile long int *) l->l_map_end;
while (p < end)
{
*p;
++p;
}
}
xdlclose (l);
return 0;
}
#include <support/test-driver.c>
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