[v2,09/11] authz: add QAuthZListFile object type for a file access control list

diff --git a/authz/Makefile.objs b/authz/Makefile.objs
index 921fa624d7..8351bf181d 100644
--- a/authz/Makefile.objs
+++ b/authz/Makefile.objs
@@ -1,3 +1,4 @@ 
 authz-obj-y += base.o
 authz-obj-y += simple.o
 authz-obj-y += list.o
+authz-obj-y += listfile.o
diff --git a/authz/listfile.c b/authz/listfile.c
new file mode 100644
index 0000000000..5bd3e37f7e
--- /dev/null
+++ b/authz/listfile.c
@@ -0,0 +1,284 @@ 
+/*
+ * 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 "authz/trace.h"
+#include "qemu/error-report.h"
+#include "qemu/main-loop.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(int 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);
+
+    fauthz->list = qauthz_list_file_load(fauthz, errp);
+
+    if (fauthz->refresh) {
+        gchar *dir, *file;
+        fauthz->file_monitor = qemu_file_monitor_get_instance(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");
+            g_free(dir);
+            return;
+        }
+        file = g_path_get_basename(fauthz->filename);
+        if (g_str_equal(file, ".")) {
+            error_setg(errp, "Path has no trailing filename component");
+            g_free(file);
+            g_free(dir);
+            return;
+        }
+
+        fauthz->file_watch = qemu_file_monitor_add_watch(
+            fauthz->file_monitor, dir, file,
+            qauthz_list_file_event, fauthz, errp);
+        g_free(file);
+        g_free(dir);
+        if (fauthz->file_watch < 0) {
+            return;
+        }
+    }
+}
+
+
+static void
+qauthz_list_file_prop_set_filename(Object *obj,
+                                   const char *value,
+                                   Error **errp G_GNUC_UNUSED)
+{
+    QAuthZListFile *authz = QAUTHZ_LIST_FILE(obj);
+
+    authz->filename = g_strdup(value);
+}
+
+
+static char *
+qauthz_list_file_prop_get_filename(Object *obj,
+                                   Error **errp G_GNUC_UNUSED)
+{
+    QAuthZListFile *authz = QAUTHZ_LIST_FILE(obj);
+
+    return g_strdup(authz->filename);
+}
+
+
+static void
+qauthz_list_file_prop_set_refresh(Object *obj,
+                                  bool value,
+                                  Error **errp G_GNUC_UNUSED)
+{
+    QAuthZListFile *authz = QAUTHZ_LIST_FILE(obj);
+
+    authz->refresh = value;
+}
+
+
+static bool
+qauthz_list_file_prop_get_refresh(Object *obj,
+                                  Error **errp G_GNUC_UNUSED)
+{
+    QAuthZListFile *authz = QAUTHZ_LIST_FILE(obj);
+
+    return authz->refresh;
+}
+
+
+static void
+qauthz_list_file_finalize(Object *obj)
+{
+    QAuthZListFile *authz = QAUTHZ_LIST_FILE(obj);
+
+    if (authz->file_watch != -1 && authz->file_monitor) {
+        gchar *dir = g_path_get_dirname(authz->filename);
+        qemu_file_monitor_remove_watch(authz->file_monitor,
+                                       dir,
+                                       authz->file_watch);
+        g_free(dir);
+    }
+    object_unref(OBJECT(authz->list));
+    g_free(authz->filename);
+}
+
+
+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,
+                                  NULL);
+    object_class_property_add_bool(oc, "refresh",
+                                   qauthz_list_file_prop_get_refresh,
+                                   qauthz_list_file_prop_set_refresh,
+                                   NULL);
+
+    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,
+                                     Error **errp)
+{
+    return QAUTHZ_LIST_FILE(
+        object_new_with_props(TYPE_QAUTHZ_LIST_FILE,
+                              object_get_objects_root(),
+                              id, errp,
+                              "filename", filename,
+                              NULL));
+}
+
+
+static const TypeInfo qauthz_list_file_info = {
+    .parent = TYPE_QAUTHZ_LIST,
+    .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);
diff --git a/authz/trace-events b/authz/trace-events
index a896d876e8..fb65349a90 100644
--- a/authz/trace-events
+++ b/authz/trace-events
@@ -9,3 +9,7 @@  qauthz_simple_is_allowed(void *authz, const char *wantidentity, const char *goti
 # auth/list.c
 qauthz_list_check_rule(void *authz, const char *identity, const char *rule, int format, int policy) "AuthZ list %p check rule=%s identity=%s format=%d policy=%d"
 qauthz_list_default_policy(void *authz, const char *identity, int policy) "AuthZ list %p default identity=%s policy=%d"
+
+# auth/listfile.c
+qauthz_list_file_load(void *authz, const char *filename) "AuthZ file %p load filename=%s"
+qauthz_list_file_refresh(void *authz, const char *filename, int success) "AuthZ file %p load filename=%s success=%d"
diff --git a/include/authz/listfile.h b/include/authz/listfile.h
new file mode 100644
index 0000000000..f6ea0ddd27
--- /dev/null
+++ b/include/authz/listfile.h
@@ -0,0 +1,105 @@ 
+/*
+ * QEMU 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/>.
+ *
+ */
+
+#ifndef QAUTHZ_LIST_FILE_H__
+#define QAUTHZ_LIST_FILE_H__
+
+#include "authz/list.h"
+#include "qapi/qapi-types-authz.h"
+#include "qemu/filemonitor.h"
+
+#define TYPE_QAUTHZ_LIST_FILE "authz-list-file"
+
+#define QAUTHZ_LIST_FILE_CLASS(klass)                        \
+    OBJECT_CLASS_CHECK(QAuthZListFileClass, (klass),        \
+                       TYPE_QAUTHZ_LIST_FILE)
+#define QAUTHZ_LIST_FILE_GET_CLASS(obj)              \
+    OBJECT_GET_CLASS(QAuthZListFileClass, (obj),    \
+                      TYPE_QAUTHZ_LIST_FILE)
+#define QAUTHZ_LIST_FILE(obj) \
+    INTERFACE_CHECK(QAuthZListFile, (obj),          \
+                    TYPE_QAUTHZ_LIST_FILE)
+
+typedef struct QAuthZListFile QAuthZListFile;
+typedef struct QAuthZListFileClass QAuthZListFileClass;
+
+
+/**
+ * QAuthZListFile:
+ *
+ * This authorization driver provides a file mechanism
+ * for granting access by matching user names against a
+ * file of globs. Each match rule has an associated policy
+ * and a catch all policy applies if no rule matches
+ *
+ * To create an instance of this class via QMP:
+ *
+ *  {
+ *    "execute": "object-add",
+ *    "arguments": {
+ *      "qom-type": "authz-list-file",
+ *      "id": "authz0",
+ *      "parameters": {
+ *        "filename": "/etc/qemu/myvm-vnc.acl",
+ *        "refresh": "yes"
+ *      }
+ *    }
+ *  }
+ *
+ * If 'refresh' is 'yes', inotify is used to monitor for changes
+ * to the file and auto-reload the rules.
+ *
+ * The myvm-vnc.acl file should contain the parameters for
+ * the QAuthZList object in JSON format:
+ *
+ *      {
+ *        "rules": [
+ *           { "match": "fred", "policy": "allow", "format": "exact" },
+ *           { "match": "bob", "policy": "allow", "format": "exact" },
+ *           { "match": "danb", "policy": "deny", "format": "exact" },
+ *           { "match": "dan*", "policy": "allow", "format": "glob" }
+ *        ],
+ *        "policy": "deny"
+ *      }
+ *
+ */
+struct QAuthZListFile {
+    QAuthZ parent_obj;
+
+    QAuthZ *list;
+    char *filename;
+    bool refresh;
+    QFileMonitor *file_monitor;
+    int file_watch;
+};
+
+
+struct QAuthZListFileClass {
+    QAuthZClass parent_class;
+};
+
+
+QAuthZListFile *qauthz_list_file_new(const char *id,
+                                     const char *filename,
+                                     Error **errp);
+
+
+#endif /* QAUTHZ_LIST_FILE_H__ */
+