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/* libnbd
* Copyright Red Hat
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/* Test the library can be loaded and unloaded using dlopen etc.
*
* We do this from a thread because of this problem identified in
* libvirt:
* https://lists.nongnu.org/archive/html/qemu-block/2021-04/msg00828.html
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <errno.h>
#include <dlfcn.h>
#include <pthread.h>
/* Define these so we don't have to include <libnbd.h>. */
struct nbd_handle;
typedef struct nbd_handle *(*nbd_create_t) (void);
typedef void (*nbd_close_t) (struct nbd_handle *h);
typedef const char *(*nbd_get_error_t) (void);
typedef char *(*nbd_get_handle_name_t) (struct nbd_handle *h);
typedef int64_t (*nbd_get_size_t) (struct nbd_handle *h);
#ifndef LIBRARY
#error "-DLIBRARY was not defined"
#endif
static const char *progname;
static void *thread_start (void *arg);
static void *read_symbol (void *lib, const char *symbol);
int
main (int argc, char *argv[])
{
pthread_t thread;
int r;
progname = argv[0];
if (access (LIBRARY, X_OK) == -1) {
fprintf (stderr, "%s: test skipped because %s cannot be accessed: %m\n",
progname, LIBRARY);
exit (77);
}
r = pthread_create (&thread, NULL, thread_start, NULL);
if (r != 0) {
errno = r;
fprintf (stderr, "%s: pthread_create failed: %m\n", progname);
exit (EXIT_FAILURE);
}
r = pthread_join (thread, NULL);
if (r != 0) {
errno = r;
fprintf (stderr, "%s: pthread_join failed: %m\n", progname);
exit (EXIT_FAILURE);
}
exit (EXIT_SUCCESS);
}
static void *
thread_start (void *arg)
{
void *lib;
nbd_create_t nbd_create;
nbd_close_t nbd_close;
nbd_get_error_t nbd_get_error;
nbd_get_handle_name_t nbd_get_handle_name;
nbd_get_size_t nbd_get_size;
struct nbd_handle *h;
char *name;
lib = dlopen (LIBRARY, RTLD_LAZY);
if (lib == NULL) {
fprintf (stderr, "%s: could not open %s: %s",
progname, LIBRARY, dlerror ());
exit (EXIT_FAILURE);
}
nbd_create = read_symbol (lib, "nbd_create");
nbd_close = read_symbol (lib, "nbd_close");
nbd_get_error = read_symbol (lib, "nbd_get_error");
nbd_get_handle_name = read_symbol (lib, "nbd_get_handle_name");
nbd_get_size = read_symbol (lib, "nbd_get_size");
/* Create a handle and try out some operations. */
h = nbd_create ();
if (h == NULL) {
fprintf (stderr, "%s: %s\n", progname, nbd_get_error ());
exit (EXIT_FAILURE);
}
name = nbd_get_handle_name (h);
printf ("handle name = \"%s\"\n", name);
free (name);
/* This deliberately is an error because I want to check that we
* don't try to free the thread-local error string by calling a
* function in the dlclosed (unmapped) library.
*/
if (nbd_get_size (h) != -1) {
fprintf (stderr, "%s: expected nbd_get_size to return an error\n",
progname);
exit (EXIT_FAILURE);
}
printf ("expected error string = \"%s\"\n", nbd_get_error ());
nbd_close (h);
if (dlclose (lib) != 0) {
fprintf (stderr, "%s: could not close %s: %s\n",
progname, LIBRARY, dlerror ());
exit (EXIT_FAILURE);
}
return NULL;
}
static void *
read_symbol (void *lib, const char *symbol)
{
void *symval;
const char *err;
dlerror (); /* Clear error indicator. */
symval = dlsym (lib, symbol);
if ((err = dlerror ()) != NULL) {
fprintf (stderr, "could not read symbol: %s: %s\n", symbol, err);
exit (EXIT_FAILURE);
}
return symval;
}
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