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/*
* Copyright (C) 2011, 2013 Red Hat, Inc.
*
* This 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.
*
* This 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 this library. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
/*
* When libvirt initializes, it creates a thread local for storing
* the last virErrorPtr instance. It also registers a cleanup
* callback for the thread local that will be invoked whenever
* a thread exits.
*
* If the libvirt.so library was dlopen()'d and is dlclose()'d
* while there is still a thread present, then when that thread
* later exits, the libvirt cleanup callback will be invoked.
* Unfortunately libvirt.so will no longer be in memory so the
* callback SEGVs (if you're lucky), or invokes unlreated
* code at the same address as the old callback (if you're
* unlucky).
*
* To fix the problem libvirt is linked '-z nodelete' which
* prevents the code being removed from memory at dlclose().
*
* This test case demonstrates this SEGV scenario. If this
* test does not SEGV, then the '-z nodelete' fix is working
*/
#include <config.h>
#define VIR_NO_GLIB_STDIO /* This file intentionally does not link to libvirt/glib */
#include "testutils.h"
#ifdef linux
# include <dlfcn.h>
# include <pthread.h>
# include <unistd.h>
# include <signal.h>
# include "internal.h"
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
bool running = false;
bool failstart = false;
bool quit = false;
static void *threadMain(void *arg)
{
int (*startup)(void) = arg;
if (startup() < 0) {
pthread_mutex_lock(&lock);
failstart = true;
pthread_cond_signal(&cond);
} else {
pthread_mutex_lock(&lock);
running = true;
pthread_cond_signal(&cond);
}
while (!quit)
pthread_cond_wait(&cond, &lock);
pthread_mutex_unlock(&lock);
return NULL;
}
static void sigHandler(int sig)
{
ignore_value(write(STDERR_FILENO, "FAIL\n", 5)); /* sc_avoid_write */
signal(sig, SIG_DFL);
raise(sig);
}
/* We're not using the testutils.c main() wrapper because
* we don't want 'shunloadtest' itself to link against
* libvirt.so. We need to test dlopen()'ing of libvirt.so
*/
int main(int argc G_GNUC_UNUSED, char **argv)
{
void (*startup)(void);
pthread_t t;
void *lib;
char *theprogname;
theprogname = argv[0];
if (STRPREFIX(theprogname, "./"))
theprogname += 2;
fprintf(stderr, "TEST: %s\n", theprogname);
fprintf(stderr, " .%*s 1 ", 39, "");
signal(SIGSEGV, sigHandler);
if (!(lib = dlopen(abs_builddir "/libshunload.so", RTLD_LAZY))) {
fprintf(stderr, "Cannot load ./libshunload.so %s\n", dlerror());
return 1;
}
if (!(startup = dlsym(lib, "shunloadStart"))) {
fprintf(stderr, "Cannot find shunloadStart %s\n", dlerror());
dlclose(lib);
return 1;
}
/*
* Create a thread which is going to initialize libvirt
* and raise an error
*/
pthread_create(&t, NULL, threadMain, startup);
/* Wait for the thread to start and call libvirt */
pthread_mutex_lock(&lock);
while (!running && !failstart)
pthread_cond_wait(&cond, &lock);
/* Close the shared library (and thus make libvirt.so
* non-resident */
dlclose(lib);
/* Tell the thread to quit */
quit = true;
pthread_cond_signal(&cond);
pthread_mutex_unlock(&lock);
pthread_join(t, NULL);
/* If we got to here the thread successfully exited without
* causing a SEGV !
*/
if (failstart)
fprintf(stderr, "FAIL to initialize libvirt\n");
else
fprintf(stderr, "OK\n");
return 0;
}
#else
int main(void)
{
return EXIT_AM_SKIP;
}
#endif
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