[PATCH v6 17/21] fuzz: add support for qos-assisted fuzz targets

["Oleinik, Alexander" <alxndr@bu.edu>]

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
---
 tests/fuzz/qos_fuzz.c | 232 ++++++++++++++++++++++++++++++++++++++++++
 tests/fuzz/qos_fuzz.h |  33 ++++++
 2 files changed, 265 insertions(+)
 create mode 100644 tests/fuzz/qos_fuzz.c
 create mode 100644 tests/fuzz/qos_fuzz.h

diff --git a/tests/fuzz/qos_fuzz.c b/tests/fuzz/qos_fuzz.c
new file mode 100644
index 0000000000..da76e28ca3
--- /dev/null
+++ b/tests/fuzz/qos_fuzz.c
@@ -0,0 +1,232 @@
+/*
+ * QOS-assisted fuzzing helpers
+ *
+ * Copyright (c) 2018 Emanuele Giuseppe Esposito <e.emanuelegiuseppe@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2 as published by the Free Software Foundation.
+ *
+ * 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 "qemu/units.h"
+#include "qapi/error.h"
+#include "qemu-common.h"
+#include "exec/memory.h"
+#include "exec/address-spaces.h"
+#include "sysemu/sysemu.h"
+#include "qemu/main-loop.h"
+
+#include <wordexp.h>
+
+#include "libqos/malloc.h"
+#include "libqos/qgraph.h"
+#include "libqos/qgraph_internal.h"
+
+#include "fuzz.h"
+#include "qos_fuzz.h"
+#include "tests/libqos/qgraph.h"
+#include "tests/libqos/qos_external.h"
+#include "tests/libqtest.h"
+
+#include "qapi/qapi-commands-machine.h"
+#include "qapi/qapi-commands-qom.h"
+#include "qapi/qmp/qlist.h"
+
+
+void *fuzz_qos_obj;
+QGuestAllocator *fuzz_qos_alloc;
+
+static const char *fuzz_target_name;
+static char **fuzz_path_vec;
+
+/*
+ * Replaced the qmp commands with direct qmp_marshal calls.
+ * Probably there is a better way to do this
+ */
+static void qos_set_machines_devices_available(void)
+{
+    QDict *req = qdict_new();
+    QObject *response;
+    QDict *args = qdict_new();
+    QList *lst;
+    Error *err = NULL;
+
+    qmp_marshal_query_machines(NULL, &response, &err);
+    assert(!err);
+    lst = qobject_to(QList, response);
+    apply_to_qlist(lst, true);
+
+    qobject_unref(response);
+
+
+    qdict_put_str(req, "execute", "qom-list-types");
+    qdict_put_str(args, "implements", "device");
+    qdict_put_bool(args, "abstract", true);
+    qdict_put_obj(req, "arguments", (QObject *) args);
+
+    qmp_marshal_qom_list_types(args, &response, &err);
+    assert(!err);
+    lst = qobject_to(QList, response);
+    apply_to_qlist(lst, false);
+    qobject_unref(response);
+    qobject_unref(req);
+}
+
+static char **current_path;
+
+void *qos_allocate_objects(QTestState *qts, QGuestAllocator **p_alloc)
+{
+    return allocate_objects(qts, current_path + 1, p_alloc);
+}
+
+static const char *qos_build_main_args(void)
+{
+    char **path = fuzz_path_vec;
+    QOSGraphNode *test_node;
+    GString *cmd_line = g_string_new(path[0]);
+    void *test_arg;
+
+    /* Before test */
+    current_path = path;
+    test_node = qos_graph_get_node(path[(g_strv_length(path) - 1)]);
+    test_arg = test_node->u.test.arg;
+    if (test_node->u.test.before) {
+        test_arg = test_node->u.test.before(cmd_line, test_arg);
+    }
+    /* Prepend the arguments that we need */
+    g_string_prepend(cmd_line,
+            TARGET_NAME " -display none -machine accel=qtest -m 64 ");
+    return cmd_line->str;
+}
+
+/*
+ * This function is largely a copy of qos-test.c:walk_path. Since walk_path
+ * is itself a callback, its a little annoying to add another argument/layer of
+ * indirection
+ */
+static void walk_path(QOSGraphNode *orig_path, int len)
+{
+    QOSGraphNode *path;
+    QOSGraphEdge *edge;
+
+    /* etype set to QEDGE_CONSUMED_BY so that machine can add to the command line */
+    QOSEdgeType etype = QEDGE_CONSUMED_BY;
+
+    /* twice QOS_PATH_MAX_ELEMENT_SIZE since each edge can have its arg */
+    char **path_vec = g_new0(char *, (QOS_PATH_MAX_ELEMENT_SIZE * 2));
+    int path_vec_size = 0;
+
+    char *after_cmd, *before_cmd, *after_device;
+    GString *after_device_str = g_string_new("");
+    char *node_name = orig_path->name, *path_str;
+
+    GString *cmd_line = g_string_new("");
+    GString *cmd_line2 = g_string_new("");
+
+    path = qos_graph_get_node(node_name); /* root */
+    node_name = qos_graph_edge_get_dest(path->path_edge); /* machine name */
+
+    path_vec[path_vec_size++] = node_name;
+    path_vec[path_vec_size++] = qos_get_machine_type(node_name);
+
+    for (;;) {
+        path = qos_graph_get_node(node_name);
+        if (!path->path_edge) {
+            break;
+        }
+
+        node_name = qos_graph_edge_get_dest(path->path_edge);
+
+        /* append node command line + previous edge command line */
+        if (path->command_line && etype == QEDGE_CONSUMED_BY) {
+            g_string_append(cmd_line, path->command_line);
+            g_string_append(cmd_line, after_device_str->str);
+            g_string_truncate(after_device_str, 0);
+        }
+
+        path_vec[path_vec_size++] = qos_graph_edge_get_name(path->path_edge);
+        /* detect if edge has command line args */
+        after_cmd = qos_graph_edge_get_after_cmd_line(path->path_edge);
+        after_device = qos_graph_edge_get_extra_device_opts(path->path_edge);
+        before_cmd = qos_graph_edge_get_before_cmd_line(path->path_edge);
+        edge = qos_graph_get_edge(path->name, node_name);
+        etype = qos_graph_edge_get_type(edge);
+
+        if (before_cmd) {
+            g_string_append(cmd_line, before_cmd);
+        }
+        if (after_cmd) {
+            g_string_append(cmd_line2, after_cmd);
+        }
+        if (after_device) {
+            g_string_append(after_device_str, after_device);
+        }
+    }
+
+    path_vec[path_vec_size++] = NULL;
+    g_string_append(cmd_line, after_device_str->str);
+    g_string_free(after_device_str, true);
+
+    g_string_append(cmd_line, cmd_line2->str);
+    g_string_free(cmd_line2, true);
+
+    /*
+     * here position 0 has <arch>/<machine>, position 1 has <machine>.
+     * The path must not have the <arch>, qtest_add_data_func adds it.
+     */
+    path_str = g_strjoinv("/", path_vec + 1);
+
+    /* Check that this is the test we care about: */
+    char *test_name = strrchr(path_str, '/') + 1;
+    if (strcmp(test_name, fuzz_target_name) == 0) {
+        /*
+         * put arch/machine in position 1 so run_one_test can do its work
+         * and add the command line at position 0.
+         */
+        path_vec[1] = path_vec[0];
+        path_vec[0] = g_string_free(cmd_line, false);
+
+        fuzz_path_vec = path_vec;
+    } else {
+        g_free(path_vec);
+    }
+
+    g_free(path_str);
+}
+
+static const char *qos_get_cmdline(FuzzTarget *t)
+{
+    /*
+     * Set a global variable that we use to identify the qos_path for our
+     * fuzz_target
+     */
+    fuzz_target_name = t->name;
+    qos_set_machines_devices_available();
+    qos_graph_foreach_test_path(walk_path);
+    return qos_build_main_args();
+}
+
+void fuzz_add_qos_target(
+        FuzzTarget *fuzz_opts,
+        const char *interface,
+        QOSGraphTestOptions *opts
+        )
+{
+    qos_add_test(fuzz_opts->name, interface, NULL, opts);
+    fuzz_opts->get_init_cmdline = qos_get_cmdline;
+    fuzz_add_target(fuzz_opts);
+}
+
+void qos_init_path(QTestState *s)
+{
+    fuzz_qos_obj = qos_allocate_objects(s , &fuzz_qos_alloc);
+}
diff --git a/tests/fuzz/qos_fuzz.h b/tests/fuzz/qos_fuzz.h
new file mode 100644
index 0000000000..6c280f07c5
--- /dev/null
+++ b/tests/fuzz/qos_fuzz.h
@@ -0,0 +1,33 @@
+/*
+ * QOS-assisted fuzzing helpers
+ *
+ * Copyright Red Hat Inc., 2019
+ *
+ * Authors:
+ *  Alexander Bulekov   <alxndr@bu.edu>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef _QOS_FUZZ_H_
+#define _QOS_FUZZ_H_
+
+#include "tests/fuzz/fuzz.h"
+#include "tests/libqos/qgraph.h"
+
+int qos_fuzz(const unsigned char *Data, size_t Size);
+void qos_setup(void);
+
+extern void *fuzz_qos_obj;
+extern QGuestAllocator *fuzz_qos_alloc;
+
+void fuzz_add_qos_target(
+        FuzzTarget *fuzz_opts,
+        const char *interface,
+        QOSGraphTestOptions *opts
+        );
+
+void qos_init_path(QTestState *);
+
+#endif
-- 
2.23.0