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/*
* virmodule.c: APIs for dlopen'ing extension modules
*
* Copyright (C) 2012-2018 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 "internal.h"
#include "virmodule.h"
#include "virerror.h"
#include "virfile.h"
#include "virlog.h"
#include "virutil.h"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("util.module");
#ifdef WITH_DLFCN_H
# include <dlfcn.h>
static void *
virModuleLoadFile(const char *file)
{
void *handle = NULL;
int flags = RTLD_NOW | RTLD_GLOBAL;
# ifdef RTLD_NODELETE
flags |= RTLD_NODELETE;
# endif
VIR_DEBUG("Load module file '%s'", file);
virUpdateSelfLastChanged(file);
if (!(handle = dlopen(file, flags))) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to load module '%s': %s"), file, dlerror());
return NULL;
}
return handle;
}
static void *
virModuleLoadFunc(void *handle,
const char *file,
const char *funcname)
{
void *regsym;
VIR_DEBUG("Lookup function '%s'", funcname);
if (!(regsym = dlsym(handle, funcname))) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to find symbol '%s' in module '%s': %s"),
funcname, file, dlerror());
return NULL;
}
return regsym;
}
/**
* virModuleLoad:
* @path: filename of module to load
* @regfunc: name of the function that registers the module
* @required: true if module must exist on disk, false to silently skip
*
* Loads a loadable module named @path and calls the
* registration function @regfunc. The module will never
* be unloaded because unloading is not safe in a multi-threaded
* application.
*
* 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
virModuleLoad(const char *path,
const char *regfunc,
bool required)
{
void *rethandle = NULL;
int (*regsym)(void);
int ret = -1;
if (!virFileExists(path)) {
if (required) {
virReportSystemError(errno,
_("Failed to find module '%s'"), path);
return -1;
} else {
VIR_INFO("Module '%s' does not exist", path);
return 1;
}
}
if (!(rethandle = virModuleLoadFile(path)))
goto cleanup;
if (!(regsym = virModuleLoadFunc(rethandle, path, regfunc)))
goto cleanup;
if ((*regsym)() < 0) {
/* regsym() should report an error itself, but lets
* just make sure */
if (virGetLastErrorCode() == VIR_ERR_OK) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to execute symbol '%s' in module '%s'"),
regfunc, path);
}
goto cleanup;
}
rethandle = NULL;
ret = 0;
cleanup:
if (rethandle)
dlclose(rethandle);
return ret;
}
#else /* ! WITH_DLFCN_H */
int
virModuleLoad(const char *path,
const char *regfunc G_GNUC_UNUSED,
bool required)
{
VIR_DEBUG("dlopen not available on this platform");
if (required) {
virReportSystemError(ENOSYS,
_("Failed to find module '%s'"), path);
return -1;
} else {
/* Since we have no dlopen(), but definition we have no
* loadable modules on disk, so we can reasonably
* return '1' instead of an error.
*/
return 1;
}
}
#endif /* ! WITH_DLFCN_H */
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