libvirt/src/driver.c
Peter Krempa 633b7592d6 daemon: Refactor connection driver module loading
Pass the registration function name to virDriverLoadModule so that we
can later call specific functions if necessary (e.g. for testing
purposes). This gets rid of the rather ugly automatic name generator and
unifies the code to load/initialize the modules.

It's also clear which registration function gets called.
2017-02-21 09:24:33 +01:00

160 lines
3.8 KiB
C

/*
* driver.c: Helpers for loading drivers
*
* Copyright (C) 2006-2011 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/>.
*
*/
#include <config.h>
#include <unistd.h>
#include "driver.h"
#include "viralloc.h"
#include "virfile.h"
#include "virlog.h"
#include "configmake.h"
VIR_LOG_INIT("driver");
#ifdef WITH_DRIVER_MODULES
/* XXX re-implement this for other OS, or use libtools helper lib ? */
# include <dlfcn.h>
# define DEFAULT_DRIVER_DIR LIBDIR "/libvirt/connection-driver"
static void *
virDriverLoadModuleFile(const char *file)
{
void *handle = NULL;
VIR_DEBUG("Load module file '%s'", file);
if (access(file, R_OK) < 0) {
VIR_INFO("Module %s not accessible", file);
return NULL;
}
virUpdateSelfLastChanged(file);
if (!(handle = dlopen(file, RTLD_NOW | RTLD_GLOBAL)))
VIR_ERROR(_("failed to load module %s %s"), file, dlerror());
return handle;
}
static void *
virDriverLoadModuleFunc(void *handle,
const char *funcname)
{
void *regsym;
VIR_DEBUG("Lookup function '%s'", funcname);
if (!(regsym = dlsym(handle, funcname)))
VIR_ERROR(_("Missing module registration symbol %s"), funcname);
return regsym;
}
/**
* virDriverLoadModuleFull:
* @path: filename of module to load
* @regfunc: name of the function that registers the module
* @handle: Returns handle of the loaded library if not NULL
*
* Loads a loadable module named @path and calls the
* registration function @regfunc. If @handle is not NULL the handle is returned
* in the variable. Otherwise the handle is leaked so that the module stays
* loaded forever.
*
* The module is automatically looked up in the appropriate place (git or
* installed directory).
*
* Returns 0 on success, 1 if the module was not found and -1 on any error.
*/
int
virDriverLoadModuleFull(const char *path,
const char *regfunc,
void **handle)
{
void *rethandle = NULL;
int (*regsym)(void);
int ret = -1;
if (!(rethandle = virDriverLoadModuleFile(path))) {
ret = 1;
goto cleanup;
}
if (!(regsym = virDriverLoadModuleFunc(rethandle, regfunc)))
goto cleanup;
if ((*regsym)() < 0) {
VIR_ERROR(_("Failed module registration %s"), regfunc);
goto cleanup;
}
if (handle)
VIR_STEAL_PTR(*handle, rethandle);
else
rethandle = NULL;
ret = 0;
cleanup:
if (rethandle)
dlclose(rethandle);
return ret;
}
int
virDriverLoadModule(const char *name,
const char *regfunc)
{
char *modfile = NULL;
int ret;
VIR_DEBUG("Module load %s", name);
if (!(modfile = virFileFindResourceFull(name,
"libvirt_driver_",
".so",
abs_topbuilddir "/src/.libs",
DEFAULT_DRIVER_DIR,
"LIBVIRT_DRIVER_DIR")))
return 1;
ret = virDriverLoadModuleFull(modfile, regfunc, NULL);
VIR_FREE(modfile);
return ret;
}
/* XXX unload modules, but we can't until we can unregister libvirt drivers */
#endif