qemu/authz/listfile.c
Markus Armbruster d2623129a7 qom: Drop parameter @errp of object_property_add() & friends
The only way object_property_add() can fail is when a property with
the same name already exists.  Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.

Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent.  Parentage is
also under program control, so this is a programming error, too.

We have a bit over 500 callers.  Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.

The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.

Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.

When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.

Drop parameter @errp and assert the preconditions instead.

There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification".  Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]
2020-05-15 07:07:58 +02:00

283 lines
7.3 KiB
C

/*
* QEMU access control list file authorization driver
*
* Copyright (c) 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 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 "qemu/osdep.h"
#include "authz/listfile.h"
#include "trace.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"
#include "qemu/sockets.h"
#include "qemu/filemonitor.h"
#include "qom/object_interfaces.h"
#include "qapi/qapi-visit-authz.h"
#include "qapi/qmp/qjson.h"
#include "qapi/qmp/qobject.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qobject-input-visitor.h"
static bool
qauthz_list_file_is_allowed(QAuthZ *authz,
const char *identity,
Error **errp)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(authz);
if (fauthz->list) {
return qauthz_is_allowed(fauthz->list, identity, errp);
}
return false;
}
static QAuthZ *
qauthz_list_file_load(QAuthZListFile *fauthz, Error **errp)
{
GError *err = NULL;
gchar *content = NULL;
gsize len;
QObject *obj = NULL;
QDict *pdict;
Visitor *v = NULL;
QAuthZ *ret = NULL;
trace_qauthz_list_file_load(fauthz, fauthz->filename);
if (!g_file_get_contents(fauthz->filename, &content, &len, &err)) {
error_setg(errp, "Unable to read '%s': %s",
fauthz->filename, err->message);
goto cleanup;
}
obj = qobject_from_json(content, errp);
if (!obj) {
goto cleanup;
}
pdict = qobject_to(QDict, obj);
if (!pdict) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, "obj", "dict");
goto cleanup;
}
v = qobject_input_visitor_new(obj);
ret = (QAuthZ *)user_creatable_add_type(TYPE_QAUTHZ_LIST,
NULL, pdict, v, errp);
cleanup:
visit_free(v);
qobject_unref(obj);
if (err) {
g_error_free(err);
}
g_free(content);
return ret;
}
static void
qauthz_list_file_event(int64_t wd G_GNUC_UNUSED,
QFileMonitorEvent ev G_GNUC_UNUSED,
const char *name G_GNUC_UNUSED,
void *opaque)
{
QAuthZListFile *fauthz = opaque;
Error *err = NULL;
if (ev != QFILE_MONITOR_EVENT_MODIFIED &&
ev != QFILE_MONITOR_EVENT_CREATED) {
return;
}
object_unref(OBJECT(fauthz->list));
fauthz->list = qauthz_list_file_load(fauthz, &err);
trace_qauthz_list_file_refresh(fauthz,
fauthz->filename, fauthz->list ? 1 : 0);
if (!fauthz->list) {
error_report_err(err);
}
}
static void
qauthz_list_file_complete(UserCreatable *uc, Error **errp)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(uc);
gchar *dir = NULL, *file = NULL;
fauthz->list = qauthz_list_file_load(fauthz, errp);
if (!fauthz->refresh) {
return;
}
fauthz->file_monitor = qemu_file_monitor_new(errp);
if (!fauthz->file_monitor) {
return;
}
dir = g_path_get_dirname(fauthz->filename);
if (g_str_equal(dir, ".")) {
error_setg(errp, "Filename must be an absolute path");
goto cleanup;
}
file = g_path_get_basename(fauthz->filename);
if (g_str_equal(file, ".")) {
error_setg(errp, "Path has no trailing filename component");
goto cleanup;
}
fauthz->file_watch = qemu_file_monitor_add_watch(
fauthz->file_monitor, dir, file,
qauthz_list_file_event, fauthz, errp);
if (fauthz->file_watch < 0) {
goto cleanup;
}
cleanup:
g_free(file);
g_free(dir);
}
static void
qauthz_list_file_prop_set_filename(Object *obj,
const char *value,
Error **errp G_GNUC_UNUSED)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
g_free(fauthz->filename);
fauthz->filename = g_strdup(value);
}
static char *
qauthz_list_file_prop_get_filename(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
return g_strdup(fauthz->filename);
}
static void
qauthz_list_file_prop_set_refresh(Object *obj,
bool value,
Error **errp G_GNUC_UNUSED)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
fauthz->refresh = value;
}
static bool
qauthz_list_file_prop_get_refresh(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
return fauthz->refresh;
}
static void
qauthz_list_file_finalize(Object *obj)
{
QAuthZListFile *fauthz = QAUTHZ_LIST_FILE(obj);
object_unref(OBJECT(fauthz->list));
g_free(fauthz->filename);
qemu_file_monitor_free(fauthz->file_monitor);
}
static void
qauthz_list_file_class_init(ObjectClass *oc, void *data)
{
UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
QAuthZClass *authz = QAUTHZ_CLASS(oc);
ucc->complete = qauthz_list_file_complete;
object_class_property_add_str(oc, "filename",
qauthz_list_file_prop_get_filename,
qauthz_list_file_prop_set_filename);
object_class_property_add_bool(oc, "refresh",
qauthz_list_file_prop_get_refresh,
qauthz_list_file_prop_set_refresh);
authz->is_allowed = qauthz_list_file_is_allowed;
}
static void
qauthz_list_file_init(Object *obj)
{
QAuthZListFile *authz = QAUTHZ_LIST_FILE(obj);
authz->file_watch = -1;
#ifdef CONFIG_INOTIFY1
authz->refresh = true;
#endif
}
QAuthZListFile *qauthz_list_file_new(const char *id,
const char *filename,
bool refresh,
Error **errp)
{
return QAUTHZ_LIST_FILE(
object_new_with_props(TYPE_QAUTHZ_LIST_FILE,
object_get_objects_root(),
id, errp,
"filename", filename,
"refresh", refresh ? "yes" : "no",
NULL));
}
static const TypeInfo qauthz_list_file_info = {
.parent = TYPE_QAUTHZ,
.name = TYPE_QAUTHZ_LIST_FILE,
.instance_init = qauthz_list_file_init,
.instance_size = sizeof(QAuthZListFile),
.instance_finalize = qauthz_list_file_finalize,
.class_size = sizeof(QAuthZListFileClass),
.class_init = qauthz_list_file_class_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_USER_CREATABLE },
{ }
}
};
static void
qauthz_list_file_register_types(void)
{
type_register_static(&qauthz_list_file_info);
}
type_init(qauthz_list_file_register_types);