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glibc/dlfcn/tst-rec-dlopen.c
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/* Test recursive dlopen using malloc hooks. | |
Copyright (C) 2015-2016 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 | |
<http://www.gnu.org/licenses/>. */ | |
#include <stdio.h> | |
#include <stdlib.h> | |
#include <malloc.h> | |
#include <dlfcn.h> | |
#define DSO "moddummy1.so" | |
#define FUNC "dummy1" | |
#define DSO1 "moddummy2.so" | |
#define FUNC1 "dummy2" | |
/* Result of the called function. */ | |
int func_result; | |
/* Prototype for my hook. */ | |
void *custom_malloc_hook (size_t, const void *); | |
/* Pointer to old malloc hooks. */ | |
void *(*old_malloc_hook) (size_t, const void *); | |
/* Call function func_name in DSO dso_name via dlopen. */ | |
void | |
call_func (const char *dso_name, const char *func_name) | |
{ | |
int ret; | |
void *dso; | |
int (*func) (void); | |
char *err; | |
/* Open the DSO. */ | |
dso = dlopen (dso_name, RTLD_NOW|RTLD_GLOBAL); | |
if (dso == NULL) | |
{ | |
err = dlerror (); | |
fprintf (stderr, "%s\n", err); | |
exit (1); | |
} | |
/* Clear any errors. */ | |
dlerror (); | |
/* Lookup func. */ | |
func = (int (*) (void)) dlsym (dso, func_name); | |
if (func == NULL) | |
{ | |
err = dlerror (); | |
if (err != NULL) | |
{ | |
fprintf (stderr, "%s\n", err); | |
exit (1); | |
} | |
} | |
/* Call func. */ | |
func_result = (*func) (); | |
/* Close the library and look for errors too. */ | |
ret = dlclose (dso); | |
if (ret != 0) | |
{ | |
err = dlerror (); | |
fprintf (stderr, "%s\n", err); | |
exit (1); | |
} | |
} | |
/* Empty hook that does nothing. */ | |
void * | |
custom_malloc_hook (size_t size, const void *caller) | |
{ | |
void *result; | |
/* Restore old hooks. */ | |
__malloc_hook = old_malloc_hook; | |
/* First call a function in another library via dlopen. */ | |
call_func (DSO1, FUNC1); | |
/* Called recursively. */ | |
result = malloc (size); | |
/* Restore new hooks. */ | |
__malloc_hook = custom_malloc_hook; | |
return result; | |
} | |
static int | |
do_test (void) | |
{ | |
/* Save old hook. */ | |
old_malloc_hook = __malloc_hook; | |
/* Install new hook. */ | |
__malloc_hook = custom_malloc_hook; | |
/* Bug 17702 fixes two things: | |
* A recursive dlopen unmapping the ld.so.cache. | |
* An assertion that _r_debug is RT_CONSISTENT at entry to dlopen. | |
We can only test the latter. Testing the former requires modifying | |
ld.so.conf to cache the dummy libraries, then running ldconfig, | |
then run the test. If you do all of that (and glibc's test | |
infrastructure doesn't support that yet) then the test will | |
SEGFAULT without the fix. If you don't do that, then the test | |
will abort because of the assert described in detail below. */ | |
call_func (DSO, FUNC); | |
/* Restore old hook. */ | |
__malloc_hook = old_malloc_hook; | |
/* The function dummy2() is called by the malloc hook. Check to | |
see that it was called. This ensures the second recursive | |
dlopen happened and we called the function in that library. | |
Before the fix you either get a SIGSEGV when accessing mmap'd | |
ld.so.cache data or an assertion failure about _r_debug not | |
beint RT_CONSISTENT. We don't test for the SIGSEGV since it | |
would require finding moddummy1 or moddummy2 in the cache and | |
we don't have any infrastructure to test that, but the _r_debug | |
assertion triggers. */ | |
printf ("Returned result is %d\n", func_result); | |
if (func_result <= 0) | |
{ | |
printf ("FAIL: Function call_func() not called.\n"); | |
exit (1); | |
} | |
printf ("PASS: Function call_func() called more than once.\n"); | |
return 0; | |
} | |
#define TEST_FUNCTION do_test () | |
#include "../test-skeleton.c" |