libvirt/src/util/virmodule.c
ramyelkest 2b6667abbf all: Replace virGetLastError with virGetLastErrorCode where we can
Replace instances where we previously called virGetLastError just to
either get the code or to check if an error exists with
virGetLastErrorCode to avoid a validity pre-check.

Signed-off-by: Ramy Elkest <ramyelkest@gmail.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2018-06-05 18:44:05 +02:00

163 lines
4.2 KiB
C

/*
* 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"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("util.module");
#ifdef HAVE_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 /* ! HAVE_DLFCN_H */
int
virModuleLoad(const char *path ATTRIBUTE_UNUSED,
const char *regfunc ATTRIBUTE_UNUSED,
bool required)
{
VIR_DEBUG("dlopen not available on this platform");
if (required) {
virReportSystemError(ENOSYS,
_("Failed to find module '%s': %s"), path);
return -1;
} else {
/* Since we have no dlopen(), but definition we have no
* loadable modules on disk, so we can resaonably
* return '1' instead of an error.
*/
return 1;
}
}
#endif /* ! HAVE_DLFCN_H */